ftp.cs.arizona.edu/ftp.cs.arizona.edu.tar/ftp.cs.arizona.edu/bib/incomplete.bib

Text File | 1996-01-25 | 267KB | 7,365 lines

@Comment(BIBTEMPLATE .)
@Comment(BIBREFERENCES stdalphabetic)
@Comment{BIBSEPARATORS ",;"}


@unpublished    ( ABHYANKAR87,
key    =    "Abhyankar \& Kashyap" ,
author    =    "Abhyankar, R. B. and Kashyap, R. L." ,
title    =    "Incomplete Information and the Relational Model of
Data" ,
note    =    "Submitted to SIGMOD 87" ,
)

@inproceedings    ( ABITEBOUL85A,
key    =    "Abiteboul" ,
author    =    "Abiteboul, S. and Grahne, G." ,
title    =    "Update semantics for incomplete databases" ,
booktitle=    "vldb" ,
address    =    "Stockholm, Sweden" ,
month    =    "aug" ,
year    =    "1985" ,
pages    =    "1--12" ,
abstract=    "A database containing some incomplete information
is viewed as a set of possible states of the real world. The semantics
of updates is given based on simple set operations on the set of
states. Some basic results concerning the capabilities of known models
of incomplete databases to handle updates are exhibited." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( ABITEBOUL87A,
key    =    "Abiteboul et al." ,
author    =    "Abiteboul, S. and Kanellakis, P. and Grahne, G." ,
title    =    "On the Representation and Querying of Sets of
Possible Worlds" ,
booktitle=    "sigmod" ,
organization=    "acm" ,
publisher=    "ACM Press" ,
address    =    "San Francisco, CA" ,
editor    =    "Dayal, U. and Traiger, I." ,
month    =    "may" ,
year    =    "1987" ,
pages    =    "34--48" ,
abstract=    "We represent a set of possible worlds using an
incomplete information database. The representation techniques that we
study form a hierarchy, which generalizes relations of constants. This
hierarchy ranges from the very simple Codd-table, (i.e., a relation of
constants and distinct variables called nulls, which stand for values
present but unknown), to much more complex mechanisms involving views
on conditioned-tables, (i.e., queries on Codd-tables together with
conditions.) The views we consider are the queries that have
polynomial data-complexity on complete information databases. Our
conditions are conjunctions of equalities and inequalities. (1) We
provide matching upper and lower bounds on the data-complexity of
testing containment, membership, and uniqueness for sets of possible
worlds and we fully classify these problems with respect to our
representation hierarchy. The most surprising result in this
classification is that: it is complete in $\{Pi_2}^{p}$, whether a set
of possible worlds represented by a Codd-table with one conjunction of
inequalities. (2) We investigate the data-complexity of querying
incomplete information databases. We examine both asking for certain
facts and for possible facts. Our approach is algebraic but our bounds
also apply to logical databases. We show that asking for a certain
fact is coNP-complete, even for a fixed first order query on a
Codd-table. We thus strengthen a lower bound of [16], who showed that
this holds for a Codd-table with a conjunction of inequalities. For
each fixed positive existential query we present a polynomial
algorithm solving the bounded possible fact problem of this query on
conditioned-tables. We show that our approach is, in a sense, the best
possible, by deriving two NP-completeness lower bounds for the bounded
possible fact problem: when the fixed query contains either negation
or recursion." ,
bibdate    =    "Fri Jul 24 14:17:36 1987" ,
owner    =    "manning" ,
)

@article    ( ABITEBOUL91,
key    =    "Abiteboul et al." ,
author    =    "Abiteboul, S. and Kanellakis, P. and Grahne, G." ,
title    =    "On the Representation and Querying of Sets of
Possible Worlds" ,
journal    =    "Theoretical Computer Science" ,
volume    =    "78" ,
number    =    "1" ,
month    =    "jan" ,
year    =    "1991" ,
pages    =    "159--187" ,
abstract=    "We represent a set of possible worlds using an
incomplete information database. The representation techniques that we
study ranges from the very simple Codd-table, (i.e., a relation of
constants and uniquely occurring variables called nulls), to much more
complex mechanisms involving views on conditioned-tables (programs
applied to Codd-tables augmented by equality and inequality
conditions). (1) We provide matching upper and lower bounds on the
data-complexity of testing containment, membership, and uniqueness for
sets of possible worlds. We fully classify these problems with respect
to our representations. (2) We investigate the data-complexity of
querying incomplete information databases for both possible and
certain facts. For each fixed positive existential query on
conditioned-tables we present a polynomial time algorithm solving the
possible fact problem. We match this upper bound by two
NP-completeness lower bounds, when the fixed query contains either
negation or recursion and is applied to Codd-tables. We show that
asking for a certain fact is coNP-complete, even for a fixed first
order query applied to a Codd-table." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( ANFINDSEN92,
key    =    "Anfindsen" ,
author    =    "Anfindsen, O. J." ,
title    =    "Multivalued Logic and Database Systems" ,
type    =    "TR" ,
number    =    "R 41/92" ,
institution=    "Norwegian Telecom Research" ,
year    =    "1992" ,
month    =    "oct" ,
abstract=    "to enter" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( ANVARI84,
key    =    "Anvari \& Rose" ,
author    =    "Anvari, M. and Rose, G. F." ,
title    =    "Fuzzy Relational Databases" ,
booktitle=    "Proceedings of the 1st International Conference on
Fuzzy Information Processing" ,
address    =    "Kuaui, HI" ,
year    =    "1984" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@incollection    ( ANVARI87,
key    =    "Anvari \& Rose" ,
author    =    "Anvari, M. and Rose, G. F." ,
title    =    "Fuzzy Relational Databases" ,
booktitle=    "Analysis of Fuzzy Information" ,
pages    =    "203--212" ,
volume    =    "2" ,
year    =    "1987" ,
abstract=    "do not have article " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( ANWAR92B,
key    =    "Anwar et al." ,
author    =    "Anwar, T. M. and Beck, H. W. and Navathe, S. B." ,
title    =    "Knowledge Mining by Imprecise Querying: A
Classification-based System" ,
booktitle=    "Proceedings of the International Conference on
Data Engineering" ,
address    =    "Tempe, AZ" ,
month    =    "feb" ,
year    =    "1992" ,
pages    =    "622--630" ,
abstract=    "Knowledge mining is the process of discovering new
knowledge that is hitherto unknown. Users with a lack of knowledge of
database schemas engage in the process of knowledge mining by posing
imprecise queries. An approach to knowledge mining by imprecise
querying is presented that utilizes conceptual clustering techniques.
In contrast to numeric or fuzzy set approaches which ultimately rely
on some distance metric and threshold to processing such queries,
conceptual clustering retrieves instances which are structurally,
semantically, and pragmatically similar to the query even though they
may not match the requirements exactly. The query processor has both a
deductive and inductive component. The deductive component finds
precise matches in the traditional sense, and the inductive component
identifies ways in which imprecise matches may be considered similar.
Ranking on similarity is done using the database taxonomy, by which
similar instances become members of the same class. Relative
similarity is determined by depth in the taxonomy. The conceptual
clustering algorithm, its use in query processing and an example are
presented." ,
bibdate    =    "Fri Sep  4 22:04:09 1992" ,
owner    =    "leoso" ,
)

@article    ( ARRAZOLA89,
key    =    "Arrazola et al." ,
author    =    "Arrazola, I. and Plainfosse, A. and Prade, H. and
Testemale, C." ,
title    =    "Extrapolation of fuzzy values from incomplete data
bases" ,
journal    =    "Information Sciences" ,
volume    =    "14" ,
number    =    "6" ,
pages    =    "???--???" ,
year    =    "1989" ,
abstract=    " This paper presents different approaches which
enable a data base management system to obtain a plausible fuzzy
estimate for an attribute value of an item for which the information
is not explicity stored in the data base. This can be made either by a
kind of analogical reasoning from information about particular items
or by means of expert rules which specify the (fuzzy) sets of possible
values of the attribute under consideration, for various classes of
items. Another kind of expert rules enables the system to computer an
estimate from the attribute value of another item provided that, in
other respects, this latter item sufficiently resembles the item, the
value of which we are interested in; then these expert rules are used
either for controlling the analogical reasoning process or for
enlarging the scope of application of the first kind of expert rules.
The different approaches are discussed in the framework of possibility
theory. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( ATZENI87,
key    =    "Atzeni \& DeBernardis" ,
author    =    "Atzeni, P. and DeBernardis, M. C." ,
title    =    "A new basis for the weak instance model" ,
booktitle=    "pods" ,
year    =    "1987" ,
pages    =    "79--86" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( ATZENI89,
key    =    "Atzeni \& Torlone" ,
author    =    "Atzeni, P. and Torlone, R." ,
title    =    "Approaches to Updates over Weak Instances" ,
year    =    "1989" ,
booktitle=    "Proc. First Symposium on Mathematical Fundamentals
of Database Systems" ,
address    =    "Visegrad, Hungary" ,
pages    =    "12--23" ,
month    =    "jun" ,
)

@article    ( ATZENI90,
key    =    "Atzeni \& DeBernardis" ,
author    =    "Atzeni, P. and DeBernardis, M. C." ,
title    =    "New Interpretation for Null Values in the Weak
Instance Model" ,
journal    =    "Journal of Computer and System Sciences" ,
volume    =    "41" ,
number    =    "1" ,
month    =    "aug" ,
year    =    "1990" ,
pages    =    "25--43" ,
abstract=    " A new definition of the weak instance model for
relational databases is presented, which does not consider the missing
values as existent though unknown, but just assumes that no
information is available about them. It is possible to associate with
the new definition logical theories that do not contain existentially
quantified variables. The new model enjoys various desirable
properties of the classic weak instance model, with respect to
dependency satisfaction, query answering, and associated logical
theories. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inbook        ( ATZENI93,
key    =    "Atzeni \& Antonellis" ,
author    =    "Atzeni, P. and De Antonellis, V." ,
title    =    "The Theory of Null Values" ,
booktitle=    "Relational Database Theory" ,
chapter    =    "6" ,
abstract=    "none" ,
publisher=    "The Benjamin/Cummings Publishing Company, Inc." ,
year    =    "1993" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( BABAD84,
key    =    "Babad \& Hoffer" ,
author    =    "Babad, Y. M. and Hoffer, J. A." ,
title    =    "Even no data has a value" ,
year    =    "1984" ,
journal    =    "cacm" ,
volume    =    "27" ,
pages    =    "748--756" ,
number    =    "8" ,
)

@article    ( BALDWIN84,
key    =    "Baldwin \& Zhou" ,
author    =    "Baldwin, J. F. and Zhou, S. Q." ,
title    =    "A Fuzzy Relational Inference Language" ,
journal    =    "Fuzzy Sets \& Systems" ,
volume    =    "14" ,
year    =    "1984" ,
pages    =    "155--174" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( BARBARA89,
key    =    "Barbar\'{a} et al." ,
author    =    "Barbar\'{a}, D. and Garc\'{\i}a--Molina, H. and
Porter, D." ,
title    =    "A Probabilistic Relational Data Model" ,
type    =    "TR" ,
number    =    "215--89" ,
institution=    "Princeton University" ,
year    =    "1989" ,
month    =    "jan" ,
abstract=    "It is often desirable to represent in a database
entities whose properties cannot be deterministically classified. We
develop a new data model that includes probabilities associated with
the values of the attributes. The notion of missing probabilities is
introduced for partially specified probability distributions. This new
model offers a richer descriptive language allowing the database to
more accurately reflect the uncertain real world. Probabilistic
analogs to the basic relational operators are defined and their
correctness is studied." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( BARBARA90,
key    =    "Barbar\'{a} et al." ,
author    =    "Barbar\'{a}, D. and Garc\'{\i}a--Molina, H. and
Porter, D." ,
title    =    "A Probabilistic Relational Data Model" ,
booktitle=    "Proceedings of the International Conference on
Extending Database Technology: Advances in Database Technology ---
EDBT '90" ,
address    =    "Venice, Italy" ,
month    =    "mar" ,
year    =    "1990" ,
pages    =    "60--74" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( BARBARA92,
key    =    "Barbar\'{a} et al." ,
author    =    "Barbar\'{a}, D. and Garc\'{\i}a--Molina, H. and
Porter, D." ,
title    =    "The Management of Probabilistic Data" ,
journal    =    "tkde" ,
volume    =    "4" ,
number    =    "5" ,
month    =    "oct" ,
year    =    "1992" ,
pages    =    "487--502" ,
abstract=    " " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@book        ( BEZDEK87,
key    =    "Bezdek" ,
author    =    "Bezdek" ,
title    =    "Analysis of Fuzzy Information (3-volume set)" ,
publisher=    "CRC Press" ,
year    =    "1987" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( BISKUP79,
key    =    "Biskup" ,
author    =    "Biskup, J." ,
title    =    "A formal approach to null values in database
relations" ,
booktitle=    "Workshop: Formal Bases for Databases" ,
editor    =    "H. Gallaire and J.M. Nicolas" ,
address    =    "Toulouse, France" ,
month    =    "dec" ,
year    =    "1979" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@incollection    ( BISKUP81,
key    =    "Biskup" ,
author    =    "Biskup, J." ,
title    =    "A Formal Approach to Null Values in Database
Relations" ,
booktitle=    "Advances in Data Base Theory" ,
editor    =    "H. Gallaire and J. Minker and J. Nicolas" ,
publisher=    "Plenum Press" ,
address    =    "New York" ,
year    =    "1981" ,
volume    =    "1" ,
pages    =    "299--341" ,
abstract=    "We study the problem of null values. By this we
mean that an attribute is applicable but its value at present is
unknown and also that an attribute is applicable but its value is
arbitrary. We adopt the view that tuples denote statements of
predicate logic about database relations. Then, a null value of the
first kind, respectively second kind,, corresponds to an existentially
quantified variable, respectively universally quantified variable. For
instance if $r$ is a database relation without null values and $X$ is
a range declaration for $r$ then the tuple
$(a,\forall,b,\exists)\ismember R$ is intended to mean ``there exists
an $x\ismember X$ such that for all $y\ismember X: (a,y,b,x)\ismember
r$''. We extend basic operations of the well-known relational algebra
to relations with null values. Using formal notions of correctness and
completeness (adapted from predicate logic) we show that our
extensions are meaningful and natural. Furthermore we reexamine the
generalized join within our framework. Finally we investigate the
algebraic structure of the class of relations with null values under a
partial ordering which can be interpreted as a kind of logical
implication." ,
bibdate    =    "Wed Jul 31 21:42:40 1991" ,
owner    =    "curtis" ,
)

@article    ( BISKUP83,
key    =    "Biskup" ,
author    =    "Biskup, J." ,
title    =    "A Foundation Of Codd's Relational Maybe-Operations" ,
journal    =    "tods" ,
volume    =    "8" ,
number    =    "4" ,
month    =    "dec" ,
year    =    "1983" ,
pages    =    "608--636" ,
keywords=    "Relational database; null value; maybe-tuple,
closed world assumption; open world assumption; representation;
information content; redundancy; relational algebra; negative
information" ,
abstract=    "Database relations which possibly contain
maybe-tuples and null values are formally interpreted by our notion of
representation, which uses classical notions of predicate logic,
elaborates Codd's proposal of maybe-tuples, and adopts Reiter's
concept of a closed world. Precise notions of information content and
redundancy, associated with our notion of representation, are
investigated. Extensions of the relational algebra to relations with
maybe-tuples and null values are proposed. Our extensions are
essentially Codd's, with some modifications. It is proved that these
extensions have natural properties which are formally stated as being
adequate and restricted. By the treatment of difference and division,
our formal framework can be used even for operations that require
``negative information.'' Finally, extensions of update operations are
discussed." ,
annote    =    "Biskup summarizes Lipski's work as observing that
besides the two extreme cases in which we know either everything or
nothing about a value, there is also the general case in which we have
partial information on a value-more precisely, in which we know that
the value is an element of some set. Vassiliou also treats another
null value, meaning ``attribute not applicable'' or ``inconsistent''.
Both approaches are seen too impractical due to the high computational
complexity of the query evaluation algorithms. Codd's proposal can be
implemented within the framework of a common relational database
system, without substantially increasing the complexity of the basic
algorithms." ,
bibdate    =    "Fri Feb  8 16:18:31 1985" ,
)

@article    ( BISKUP84,
key    =    "Biskup" ,
author    =    "Biskup, J." ,
title    =    "Extending the relational algebra for relations
with maybe tuples and existential and universal null values" ,
journal    =    "Fundamenta Informatic\ae" ,
volume    =    "VII" ,
number    =    "1" ,
year    =    "1984" ,
pages    =    "129--150" ,
keywords=    "do not have article " ,
abstract=    "do not have article " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( BOLLOJU90,
key    =    "Bolloju" ,
author    =    "Bolloju, N" ,
title    =    "Modelling of Imprecise and Uncertain Information" ,
booktitle=    "Proc. Conf. on Management of Data (COMAN '90)" ,
address    =    "New Delhi, India" ,
month    =    "dec" ,
year    =    "1990" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( BORGIDA85A,
key    =    "Borgida" ,
author    =    "Borgida, A." ,
title    =    "Language features for flexible handling of
exceptions in information systems" ,
year    =    "1985" ,
journal    =    "tods" ,
volume    =    "10" ,
pages    =    "565--603" ,
number    =    "4" ,
)

@inproceedings    ( BORGIDA85B,
key    =    "Borgida \& Williamson" ,
author    =    "Borgida, A. and Williamson, K. E." ,
title    =    "Accommodating exceptions in databases, and
refining the schema by learning from them" ,
year    =    "1985" ,
booktitle=    "vldb" ,
address    =    "Stockholm" ,
)

@inproceedings    ( BORGIDA89,
key    =    "Borgida \& Etherington" ,
author    =    "Borgida, A. and Etherington, D." ,
title    =    "Hierarchical Knowledge Bases and Efficient
Disjunctive Reasoning" ,
year    =    "1989" ,
pages    =    "33--43" ,
booktitle=    "Proc. First International Conference on Principles
of Knowledge Representation and Reasoning" ,
address    =    "Toronto" ,
month    =    "may" ,
)

@article    ( BOSC88,
key    =    "Bosc et al." ,
author    =    "Bosc, P. and Galibourg, M. and Hamon, G." ,
title    =    "Fuzzy Querying with SQL: Extensions and
Implementation Aspects" ,
journal    =    "Fuzzy Sets \& Systems" ,
volume    =    "28" ,
year    =    "1988" ,
pages    =    "333--349" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( BOSC89,
key    =    "Bosc \& Galibourg" ,
author    =    "Bosc, P. and Galibourg, M." ,
title    =    "Indexing principles for a fuzzy data base" ,
journal    =    "Information Sciences" ,
volume    =    "14" ,
number    =    "6" ,
pages    =    "493--???" ,
year    =    "1989" ,
abstract=    " Up to now, many theoretical works about fuzzy
databases have been defined by designing some extension of the
relational model. Our purpose is to discuss some implementation
aspects related to these databases. This point of view does not seem
to be a usual concern of such systems, whereas it is of prime
importance with respect to their future performances. We focus on the
evaluation of a class of queries, called mono-attribute restrictions.
We show how some basic principles can be applied to improve such a
'fuzzy associative' retrieval, by means of an indexing-like access
method. Lastly, some implementation solutions are presented. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( BOSC90,
key    =    "Bosc \& Pivert" ,
author    =    "Bosc, P. and Pivert, O." ,
title    =    "Some Algorithms for Evaluating Fuzzy Relational
Queries" ,
booktitle=    "Int. Conf. on Information Processing and
Management of Uncertainty in Knowledge-Based Systems" ,
year    =    "1990" ,
pages    =    "431--442" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( BOSC91,
key    =    "Bosc \& Pivert" ,
author    =    "Bosc, P. and Pivert, O." ,
title    =    "About Equivalences in SQLf, a Relational Language
Supporting Imprecise Querying" ,
booktitle=    "Proc. International Fuzzy Engineering Symposium" ,
address    =    "Yokohama, Japan" ,
year    =    "1991" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( BOSC92A,
key    =    "Bosc \& Pivert" ,
author    =    "Bosc, P. and Pivert, O." ,
title    =    "Some Properties of Alpha-Cuts of Fuzzy Predicates" ,
booktitle=    "Proc 11th European Meeting on Cybernetics and
Systems Research" ,
address    =    "Vienna, Austria" ,
year    =    "1992" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( BOSC92B,
key    =    "Bosc \& Pivert" ,
author    =    "Bosc, P. and Pivert, O." ,
title    =    "On the Evaluation of Fuzzy Quantified Queries in a
Database Management System" ,
booktitle=    "Proceedings of the North American Fuzzy
Information Society" ,
year    =    "1992" ,
month    =    "dec" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( BOWERS84,
key    =    "Bowers" ,
author    =    "Bowers, D. S." ,
title    =    "A database architecture for aggregate-incomplete
data" ,
year    =    "1984" ,
journal    =    "The Computer Journal" ,
volume    =    "27" ,
number    =    "4" ,
pages    =    "294--300" ,
)

@inproceedings    ( BREWKA90,
key    =    "Brewka" ,
author    =    "Brewka, G." ,
title    =    "Handling Incomplete Knowledge in Artificial
Intelligence" ,
booktitle=    "Information Systems and Artificial Intelligence:
Integration Aspects" ,
address    =    "Berlin" ,
editor    =    "Kargiannis, D." ,
month    =    "Mar" ,
year    =    "1990" ,
pages    =    "11--29" ,
abstract=    "In this paper we first discuss the important role
of nonmonotonic reasoning for Artificial Intelligence. After
presenting some simple forms of nonmonotonicity as they arise in
various well-known AI systems we present in Section 2 some of the most
important existing nonmonotonic logics: McCarthy's circumscription,
Moore's autoepistemic logic, and Reiter's default logic. Section 3
examines an approach in which default reasoning is reduced to
reasoning in the presence of inconsistent information. The approach is
based on the notion of preferred maximal consistent subsets. It is
shown that these preferred subsets can be defined in such a way that
it is possibly (sic) to represent priorities between defaults
adequately. Section 4 briefly discusses the problem of implementing
nonmonotonic systems." ,
bibdate    =    "Sun Apr  7 17:11:20 1991" ,
owner    =    "curtis" ,
)

@techreport    ( BROWN90,
key    =    "Brown \& Markert" ,
author    =    "Brown, D. E. and Markert, W. J." ,
title    =    "Uncertainty Management with Imprecise Knowledge
with Application to Design" ,
type    =    "IPC-TR-" ,
number    =    "90-001" ,
institution=    "University of Virginia" ,
year    =    "1990" ,
month    =    "jan" ,
abstract=    "Uncertainty management is critical to the
effective use of knowledge-based systems in a wide variety of domains.
Design is typical of these domains in that the implementation of a
design in an artifact, the future environment for the artifact, and
the component characteristics of the artifact are all uncertain.
Existing probabilistic schemes to address the inherent uncertainty in
areas like design assume precise knowledge of the probabilities of
relevant events. This paper defines a probabilistic method for
uncertainty management with imprecise inputs. The approach combines
Bayesian inference networks and information theoretic inference
procedures. The resulting scheme manages both imprecision and
uncertainty in the problem domain. An application of the approach to
material design is described." ,
bibdate    =    "Wed Apr  1 15:20:41 1992" ,
owner    =    "curtis" ,
)

@article    ( BRUDNO88,
key    =    "Brudno" ,
author    =    "Brudno, V. A." ,
title    =    "Estimating the unknown values in a database with
incomplete information" ,
journal    =    "Automation and Remote Control" ,
volume    =    "49" ,
number    =    "1" ,
month    =    "jan" ,
year    =    "1988" ,
pages    =    "114--119" ,
abstract=    "do not have article TJ 212 A73" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( BRUDNO89,
key    =    "Brudno" ,
author    =    "Brudno, V. A." ,
title    =    "Valuations in Incomplete Information Databases" ,
journal    =    "Information Sciences" ,
volume    =    "47" ,
year    =    "1989" ,
pages    =    "389--398" ,
abstract=    "Two types of valuations for a query expression in
a relational database with incomplete tuples (values of some
attributes missing) are presented. Valuations are computed at the
intentional level as consequences of given integrity constraints." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( BUCKLES82,
key    =    "Buckles \& Petry" ,
author    =    "Buckles, B. P. and Petry, F. E." ,
title    =    "A fuzzy representation of data for relational
databases" ,
journal    =    "Fuzzy Sets and Systems" ,
volume    =    "7" ,
number    =    "3" ,
month    =    "may" ,
year    =    "1982" ,
pages    =    "213--226" ,
keywords=    "do not have article " ,
abstract=    "do not have article " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@incollection    ( BUCKLES82A,
key    =    "Buckles \& Petry" ,
author    =    "Buckles, B. P. and Petry, F. E." ,
title    =    "Fuzzy databases and their applications" ,
booktitle=    "Fuzzy Information and Decision Processes" ,
editor    =    "M.M. Gupta and E. Sanchez" ,
publisher=    "North-Holland" ,
address    =    "Amsterdam" ,
year    =    "1982" ,
pages    =    "361--371" ,
abstract=    "do not have article " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( BUCKLES82B,
key    =    "Buckles \& Petry" ,
author    =    "Buckles, B. P. and Petry, F. E." ,
title    =    "Security and Fuzzy Databases" ,
booktitle=    "IEEE 1982 Proc. of the Int. Conf. on Cybernetics
and Society" ,
year    =    "1982" ,
pages    =    "213--226" ,
abstract=    "do not have " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( BUCKLES83,
key    =    "Buckles \& Petry" ,
author    =    "Buckles, B. P. and Petry, F. E." ,
title    =    "Information Theoretical Characterization of Fuzzy
Relational Databases" ,
journal    =    "IEEE Transactions on Systems, Man and Cybernetics" ,
volume    =    "SMC-13" ,
number    =    "1" ,
year    =    "1983" ,
pages    =    "74--77" ,
abstract=    "A fuzzy relational database is a medium capable of
representing information that is inherently imprecise or is the
aggregation of the subjective opinions of a number of individuals.
Measuring the degree of precision or lack thereof is important for two
reasons. First, if the measures themselves achieve extrema when
conditions match what is intuitively recognized as maximum and minimum
fuzziness, then confidence in the medium to faithfully represent the
intervening range of precision is increased. Second, querying fuzzy
information may result in ambiguous replies and measures of
preciseness may fathom how well the query discriminated among the
possible replies. Entropy measures based on the fuzzy and
probabilistic attributes of databases are devloped as applied to the
two ends mentioned above." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( BUCKLES83A,
key    =    "Buckles \& Petry" ,
author    =    "Buckles, B. P. and Petry, F. E." ,
title    =    "Extension of the fuzzy database with fuzzy
arithmetic" ,
booktitle=    "Proceedings of the IFAC Symposium, Fuzzy
Information, Knowledge Representation and Decision Processes" ,
address    =    "Marseille, France" ,
month    =    "jul" ,
year    =    "1983" ,
pages    =    "409--414" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( BUCKLES83B,
key    =    "Buckles \& Petry" ,
author    =    "Buckles, B. P. and Petry, F. E." ,
title    =    "Query Languages for Fuzzy Databases" ,
booktitle=    "Management Decision Support Systems" ,
year    =    "1983" ,
pages    =    "241--252" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( BUCKLES84,
key    =    "Buckles \& Petry" ,
author    =    "Buckles, B. P. and Petry, F. E." ,
title    =    "Extending the fuzzy database with fuzzy numbers" ,
journal    =    "Information Science" ,
number    =    "34" ,
year    =    "1984" ,
pages    =    "145--155" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( BUCKLES85,
key    =    "Buckles \& Petry" ,
author    =    "Buckles, B. P. and Petry, F. E." ,
title    =    "Uncertainty Models in Information and Database
Systems" ,
journal    =    "Information Sciences" ,
volume    =    "11" ,
year    =    "1985" ,
pages    =    "77--87" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( BUCKLES86,
key    =    "Buckles et al." ,
author    =    "Buckles, B. P. and Petry, F. E. and Sachar, H." ,
title    =    "Retrieval and Design Concepts for Similarity-based
(Fuzzy) Relational Databases" ,
booktitle=    "Robotics and Expert Systems - 1986, Proceedings of
ROBEXS'86: The Second Annual Workshop on Robotics and Expert Systems" ,
address    =    "Houston, TX" ,
month    =    "jun" ,
year    =    "1986" ,
pages    =    "335--343" ,
abstract=    "The central idea of similarity-based databases is
that equivalence or identity relationships among attribute values are
replaced with a measure of ``nearness'', the similarity relationship.
Because separate attribute values are thus not semantically distinct
entities, the functional dependencies between attributes must reflect
the similarity between key attributes values. Matching operations
between query terms and attribute values is inexact. The truth value
of a match also uses the similarity relationship as a basis." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@incollection    ( BUCKLES87,
key    =    "Buckles \& Petry" ,
author    =    "Buckles, B. P. and Petry, F. E." ,
title    =    "Generalized Database and Information Systems" ,
booktitle=    "Analysis of Fuzzy Information" ,
year    =    "1987" ,
pages    =    "177--201" ,
volume    =    "2" ,
abstract=    "do not have article " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( BUCKLES91,
key    =    "Buckles \& Petry" ,
author    =    "Buckles, B. P. and Petry, F. E." ,
title    =    "Towards a Fuzzy Object-Oriented Data Model" ,
booktitle=    "Proceedings of NAFIPS, the North American Fuzzy
Info. Proc. Society `91" ,
month    =    "may" ,
year    =    "1991" ,
pages    =    "73--77" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( BUNEMAN87,
key    =    "Buneman et al." ,
author    =    "Buneman, P. and Davidson, S. B. and Watters, A." ,
title    =    "Querying Independent Databases" ,
journal    =    "Information Sciences" ,
volume    =    "43" ,
number    =    "1" ,
month    =    "aug" ,
year    =    "1987" ,
pages    =    "170--218" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( BUNEMAN88,
key    =    "Buneman et al." ,
author    =    "Buneman, P. and Davidson, S. B. and Watters, A." ,
title    =    "A Semantics for Complex Objects and Approximate
Queries" ,
booktitle=    "pods" ,
address    =    "Austin, TX" ,
month    =    "March" ,
year    =    "1988" ,
pages    =    "305--314" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( BUNEMAN90,
key    =    "Buneman et al." ,
author    =    "Buneman, P. and Davidson, S. B. and Watters, A." ,
title    =    "A Semantics for Complex Objects and Approximate
Answers" ,
journal    =    "Journal of Computer and System Sciences" ,
month    =    "aug" ,
year    =    "1990" ,
pages    =    "170--218" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( CASEAU91,
key    =    "Caseau" ,
author    =    "Caseau, Y." ,
title    =    "Constraints in an Object-Oriented Deductive
Database" ,
booktitle=    "Proc. of the Int. Conf. on Deductive and
Object-Oriented Databases (DOOD'91)" ,
address    =    "Munich, Germany" ,
month    =    "dec" ,
year    =    "1991" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( CAVALLO87,
key    =    "Cavallo \& Pittarelli" ,
author    =    "Cavallo, R. and Pittarelli, M." ,
title    =    "The Theory of Probabilistic Databases" ,
booktitle=    "vldb" ,
address    =    "Brighton, England" ,
editor    =    "Hammersley, P." ,
month    =    "sep" ,
year    =    "1987" ,
pages    =    "71--81" ,
abstract=    "A theory of probabilistic databases is outlined.
This theory is one component of an integrated approach to
data-modelling that accommodates both probabilistic and relational
data. In fact, many of the results presented here were developed in
the context of a framework for structural modelling of systems. Much
that is fundamental to relational database theory was also developed
in this context, and previous to the introduction by Codd of the
relational model of data. Probabilistic databases can store types of
information that cannot be represented using the relational model.
Probabilistic databases may also be viewed as generalizations of
relational databases; any relational database can be represented
without loss of information by a probabilistic database. A number of
relational database concepts are shown to have probabilistic
counterparts. In many cases, it is preferable to deal with the
probabilistic formulation of a concept even when applying it to a
relational database. For example, we define a new project-join mapping
for relational databases that is based on transforming a relational to
a probabilistic database. This mapping is shown to have more fixed
points than the standard one." ,
bibdate    =    "Sun Apr  7 17:11:20 1991" ,
owner    =    "curtis" ,
)

@article    ( CHAN93,
key    =    "Chan" ,
author    =    "Chan, E." ,
title    =    "A Possible World Semantics for Disjunctive
Databases" ,
journal    =    "tkde" ,
volume    =    "5" ,
number    =    "2" ,
month    =    "apr" ,
year    =    "1993" ,
pages    =    "282--292" ,
abstract=    "We investigate the fundamental problem of when a
ground atom in a disjunctive database is assumed false. There are
basically two different approaches for inferring negative information
for disjunctive databases; they are Minker's Generalized Closed World
Assumption (GCWA) and Ross and Topor's Disjunctive Database Rule
(DDR). A problem with the GCWA is that disjunctive clauses are
sometimes interpreted exclusively, even when they are intended for
inclusive interpretation. On the other hand, the DDR always interprets
disjunctive clauses inclusively. We argue that neither approach is
satisfactory. Whether a disjunctive clause is interpreted exclusively
or inclusively should be specified explicitly. Negative information
should then be inferred according to the stated intent of the
disjunctive clauses. A database semantics called PWS is proposed to
solve the aforementioned problem. We also show that for propositional
databases with no negative clauses, the problem of determining if a
negative ground literal is inferred under the GCWA is co-NP-hard,
while the same problem can be solved efficiently under the DDR and
PWS. However, in the general case, the problem becomes co-NP-complete
for the DDR and PWS. Relationships among GCWA, DDR, and PWS are
highlighted. In general, disjunctive clauses are interpreted
inclusively under the DDR and unpredictably under the GCWA. We also
characterize when the GCWA interprets disjunctive clauses exclusively.
Throughout this paper, we assume that both the head and the body of a
clause consists of atoms only." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( CHANDRASEKARAN82,
key    =    "Chandrasekaran et al." ,
author    =    "Chandrasekaran, B. and Mittal, S. and Smith, J. W." ,
title    =    "Reasoning with Uncertain Knowledge: The MDX
Approach" ,
booktitle=    "AMIA Congress 82" ,
publisher=    "Masson Publishing" ,
address    =    "NY" ,
editor    =    "Lindberg, D.A.B. et al." ,
year    =    "1982" ,
pages    =    "335--339" ,
abstract=    "Traditional approaches to handling uncertainty
inherent in medical knowledge and data have tried to reduce all kinds
of uncertainty to a single scale, manipulated by global rules of
combination. This paper presents an alternate scheme, as implemented
in the MDX diagnosis system. This scheme is based on two key ideas. 1)
Uncertainty in medical data is handled by a database system with
strategies that can be specialized for this purpose. 2) In the
diagnostic structure, each hypothesis is assigned one of a small
number of states of uncertainty, which is computed by a multilayered
abstraction hierarchy. Each layer of the hierarchy combines the
constituent pieces of evidence to form a symbolic uncertainty measure
for the next higher level." ,
bibdate    =    "Thu Jan 15 15:37:14 1987" ,
owner    =    "manning" ,
)

@article    ( CHANG78,
key    =    "Chang \& Ke" ,
author    =    "Chang, S. K. and Ke, J. S." ,
title    =    "Database Skeleton and its Application to Fuzzy
Query Translation" ,
journal    =    "tse" ,
volume    =    "SE-4" ,
year    =    "1978" ,
pages    =    "31--43" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( CHANG79,
key    =    "Chang \& Ke" ,
author    =    "Chang, S. K. and Ke, J. S." ,
title    =    "Translation of fuzzy queries for relational
database systems" ,
journal    =    "IEEE Transactions on Pattern Analysis and Machine
Intelligence (PAMI-1)" ,
year    =    "1979" ,
pages    =    "281--294" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( CHISHOLM87,
key    =    "Chisholm et al." ,
author    =    "Chisholm, P. and Chen, G. and Ferbrache, D. and
Thanisch, P. and Williams, M. H." ,
title    =    "Coping with indefinite and negative data in
deductive databases: A survey" ,
journal    =    "Data \& Knowledge Engineering" ,
volume    =    "2" ,
year    =    "1987" ,
pages    =    "259--284" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( CHUNG90,
key    =    "Chung et al." ,
author    =    "Chung, Jen-Yao and Jane W. S. Liu and Kwei-Jay Lin" ,
title    =    "Scheduling Periodic Jobs That Allow Imprecise
Results" ,
journal    =    "IEEE Transactions on Computers" ,
volume    =    "39" ,
number    =    "9" ,
month    =    "sep" ,
year    =    "1990" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( CIACCIA89,
key    =    "Ciaccia \& Scalas" ,
author    =    "Ciaccia, P. and Scalas, M." ,
title    =    "Optimization Strategies for Relational Disjunctive
Queries" ,
journal    =    "tse" ,
volume    =    "15" ,
number    =    "10" ,
month    =    "oct" ,
year    =    "1989" ,
pages    =    "1217--1235" ,
keywords=    "disjunctive expressions; join algorithms; query
models; query optimization; relational databases" ,
abstract=    "The main purpose of this work is to extend the
processing capabilities of the optimizer of a relational DBMS in order
to effectively include the treatment of disjunctive queries. To this
aim two new strategies are presented, whose main features are based on
the application of splitting techniques during the execution of the
join operations. Their effectiveness is first shown by means of an
example; then some comparisons with standard procedures are made,
showing promising results. The inclusion of these techniques in the
relational query processing environment requires a broader view of the
evaluation phase, where more than one expression can now be present. A
heuristic algorithm for the reduction of the number of candidate
relational expressions is also proposed." ,
bibdate    =    "Fri Oct  6 11:10:31 1989" ,
owner    =    "robyn" ,
)

@article    ( CODD79A,
key    =    "Codd" ,
author    =    "Codd, E. F." ,
title    =    "Extending the Database Relational Model to Capture
More Meaning" ,
journal    =    "tods" ,
month    =    "dec" ,
year    =    "1979" ,
pages    =    "397--434" ,
volume    =    "4" ,
number    =    "4" ,
bibdate    =    "Wed Dec 29 16:55:51 1982" ,
keywords=    "relation, relational database, relational model,
relational schema, database, data model, database schema, data
semantics, semantic model, knowledge representation, knowledge base,
conceptual model, conceptual schema, entity model" ,
abstract=    "During the last three or four years several
investigators have been exploring 'semantic models' for formatted
databases. The intent is to capture (in a more or less formal way)
more of the meaning of the data so that database design can become
more systematic and the database system itself can behave more
intelligently. Two major thrusts are clear: (1) the search for
meaningful units that are as small as possible - atomic semantics; (2)
the search for meaningful units that are larger than the usual n-ary
relation - molecular semantics. In this paper we propose extensions to
the relational model to support certain atomic and molecular
semantics. These extensions represent a synthesis of many ideas from
the published work in semantic modeling plus the introduction of new
rules for insertion, update, and deletion, as well as new algebraic
operators." ,
)

@article    ( CODD86B,
key    =    "Codd" ,
author    =    "Codd, E. F." ,
title    =    "Missing Information (Applicable and Inapplicable)
in Relational Databases" ,
journal    =    "sigmod" ,
publisher=    "ACM" ,
volume    =    "15" ,
number    =    "4" ,
month    =    "dec" ,
year    =    "1986" ,
pages    =    "53--78" ,
abstract=    "There has been some technical and justified
criticism of the treatment of missing information in the data
sublanguage SQL and in IBM's Database 2 system (a relational database
management system). Some of this criticism has been directed (by
mistake) at the relational model. The purpose of this paper is to
clarify and extend the treatment of missing information by the
relational model. The clarification places heavy emphasis on the
semantic aspects of missing information. The extension, which is
relatively minor, provides a systematic approach (independent of data
type) to dealing with the inapplicability of certain properties to
some objects. This This extension does not invalidate any part of the
present version of the relational model." ,
bibdate    =    "Tue Jan  6 17:24:31 1987" ,
owner    =    "manning" ,
)

@article    ( CODD87,
key    =    "Codd" ,
author    =    "Codd, E. F." ,
title    =    "More Commentary on Missing Information in
Relational Databases (Applicable and Inapplicable Information)" ,
journal    =    "sigmod" ,
publisher=    "acm" ,
volume    =    "16" ,
number    =    "1" ,
month    =    "mar" ,
year    =    "1987" ,
pages    =    "42--50" ,
abstract=    "My earlier paper TRI/EFC-4 from The Relational
Institute on this subject was published in ACM SIGMOD Record,
December, 1986. As a result, I have received several comments and
proposed changes. The purpose of this paper is to respond to these
items, while continuing to place heavy emphasis on the semantic
aspects of missing information. The response is principally further
explanation, but a few changes of a quite minor character are
proposed. In this paper, the reader is assumed to have read TRI/EFC-4." ,
bibdate    =    "Wed May  6 17:58:23 1987" ,
owner    =    "manning" ,
)

@inbook        ( CODD90A,
key    =    "Codd" ,
author    =    "Codd, E. F." ,
title    =    "Missing Information" ,
booktitle=    "The Relational Model for Database Management:
Version 2" ,
chapter    =    "8--9" ,
abstract=    "do not have article" ,
publisher=    "Addison-Wesley Publishing Company, Inc." ,
year    =    "1990" ,
)

@inproceedings    ( CROSS91,
key    =    "Cross \& Sudkamp" ,
author    =    "Cross, V. and Sudkamp, T." ,
title    =    "Representation and support generation in fuzzy
relational databases" ,
booktitle=    "Proceedings of the IEEE 1991 National Aerospace
and Electronics Conference - NAECON 1991" ,
address    =    "Dayton, OH" ,
month    =    "may" ,
year    =    "1991" ,
pages    =    "1136--1143" ,
abstract=    " It is pointed out that standard relational
database management systems are incapable of representing and
manipulating the imprecise, incomplete, and vague information that is
typically encountered in complex problem domains. Fuzzy relational
databases have been developed to increase the flexibility in the
representation of domain information. The different models of fuzzy
relations and their roles in the framework of fuzzy relational
database management systems are reviewed. The applicability of fuzzy
relational database techniques as a methodology for approximate
reasoning is examined. Many similarities exist in the processes that
are used for fuzzy relational operations and those of approximate
reasoning; however, the goals are often different. In fuzzy relational
database theory, the objective is measuring similarity. For
approximate reasoning, the objective is determining maximal
compatibility. Several classes of similarity measures are examined to
determine their appropriateness as compatibility measures in
approximate reasoning. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( DANFORTH92A,
key    =    "Danforth \& Valduriez" ,
author    =    "Danforth, S. and Valduriez, P." ,
title    =    "The data model of FAD: a database programming
language" ,
journal    =    "Information Sciences" ,
volume    =    "60" ,
number    =    "1992" ,
pages    =    "51--75" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( DATE82,
key    =    "Date" ,
author    =    "Date, C. J." ,
title    =    "Null Values in Database Management" ,
booktitle=    "Proceedings of the 2nd British National Conference
on Databases" ,
address    =    "Bristol, England" ,
month    =    "jul" ,
year    =    "1982" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inbook        ( DATE86D,
key    =    "Date" ,
author    =    "Date, C. J." ,
title    =    "Null Values in Database Management" ,
booktitle=    "Relational Database: Selected Writings" ,
publisher=    "Addison-Wesley" ,
address    =    "Reading, MA" ,
year    =    "1986" ,
chapter    =    "15" ,
pages    =    "313--334" ,
abstract=    "We examine the question of null values in a
database system. We begin by defining the term ``null value'' and
outlining the problems that null values are intended to solve. We go
on to discuss the properties of null values in detail, and describe
some extensions to the relational model for dealing with such values.
We then discuss some of the difficulties that occur in connexion with
the null value concept. It is our opinion that the problem is
generally not well understood, and that any attempt to incorporate
support for null values into an implemented system should be
considered premature at this time. We sketch an alternative approach
based on the concept of default values." ,
bibdate    =    "Thu Sep  3 10:03:47 1987" ,
owner    =    "manning" ,
)

@inbook        ( DATE86K,
key    =    "Date" ,
author    =    "Date, C. J." ,
title    =    "NOT is Not `Not'! (notes on three-valued logic and
related matters)" ,
booktitle=    "Relational Database Writings 1985 - 1989" ,
publisher=    "Addison-Wesley" ,
address    =    "Reading, MA" ,
year    =    "1989" ,
chapter    =    "8" ,
pages    =    "217--248" ,
abstract=    "do not have" ,
bibdate    =    "Thu Sep  3 10:03:47 1987" ,
owner    =    "curtis" ,
)

@inbook        ( DATE86L,
key    =    "Date" ,
author    =    "Date, C. J." ,
title    =    "EXISTS is Not `Exists'! (some logical flaws in
SQL)" ,
booktitle=    "Relational Database Writings 1985 - 1989" ,
publisher=    "Addison-Wesley" ,
address    =    "Reading, MA" ,
year    =    "1989" ,
chapter    =    "13" ,
pages    =    "339--356" ,
abstract=    "do not have" ,
bibdate    =    "Thu Sep  3 10:03:47 1987" ,
owner    =    "curtis" ,
)

@article    ( DATRI89,
key    =    "D'Atri \& Tarantino" ,
author    =    "D'Atri, A. and Tarantino, L." ,
title    =    "From Browsing to Querying" ,
journal    =    "IEEE Database Engineering Bulletin - Special Issue
on Imprecision in Databases" ,
volume    =    "12" ,
number    =    "2" ,
month    =    "jun" ,
year    =    "1989" ,
pages    =    "46--53" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( DAYON90,
key    =    "Dayon" ,
author    =    "Dayon, B." ,
title    =    "Reliability of Answers to an SQL Query" ,
type    =    "TR" ,
institution=    "Department of Computer Sciences, Concordia
University" ,
year    =    "1990" ,
month    =    "may" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( DEAN88A,
key    =    "Dean \& Boddy" ,
author    =    "Dean, T. and Boddy, M." ,
title    =    "Reasoning About Partially Ordered Events" ,
journal    =    "Artificial Intelligence" ,
volume    =    "36" ,
number    =    "3" ,
month    =    "oct" ,
year    =    "1988" ,
pages    =    "375--399" ,
abstract=    " This paper describes a class of temporal
reasoning problems involving events whose order is not completely
known. We examine the complexity of such problems and show that for
all but trivial cases these problems are likely to be intractable. As
an alternative to a complete, but potentially exponential-time
decision procedure, we provide a partial decision procedure that
reports useful results and runs in polynomial time. (Author abstract).
" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( DEMICHIEL89,
key    =    "Demichiel" ,
author    =    "Demichiel, L. G." ,
title    =    "Resolving Database Incompatibility: An Approach to
Performing Relational Operations over Mismatched Domains" ,
journal    =    "tkde" ,
volume    =    "1" ,
number    =    "4" ,
month    =    "dec" ,
year    =    "1989" ,
pages    =    "485--493" ,
abstract=    "We present a solution to the problem of supporting
relational database operations despite domain mismatch. Mismatched
domains occur when information must be obtained from databases that
were developed independently. We resolve domain differences by mapping
conflicting attributes to common domains by means of a mechanism of
virtual attributes and then apply a set of extended relational
operations to the resulting values. When one-one mappings cannot be
established between domains, the values that result from attribute
mappings may be partial. We define a set of extended relational
operators that formalize operations over partial values and thus
manipulate the incomplete information that results from resolving
domain mismatch." ,
bibdate    =    "Mon Feb 25 08:50:27 1991" ,
owner    =    "robyn" ,
)

@phdthesis    ( DEMICHIEL89A,
key    =    "Demichiel" ,
author    =    "Demichiel, L. G." ,
title    =    "Performing Database Operations over Mismatched
Domains" ,
year    =    "1989" ,
school    =    "Department of Computer Sciences, Stanford
University" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( DEMOLOMBE85,
key    =    "Demolombe \& Fari\~{n}as" ,
author    =    "Demolombe, R. and Fari\~{n}as del Cerro, L." ,
title    =    "Efficient Representation of Incomplete Information
About Structured Objects" ,
booktitle=    "Proc. of the Workshop on Knowledge Base Management
Systems " ,
address    =    "Crete" ,
month    =    "jun" ,
year    =    "1985" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( DEMOLOMBE88,
key    =    "Demolombe \& Fari\~{n}as" ,
author    =    "Demolombe, R. and Fari\~{n}as del Cerro, L." ,
title    =    "An Algebraic Evaluation Method for Deduction in
Incomplete Databases" ,
journal    =    "The Journal of Logic Programming" ,
volume    =    "5" ,
number    =    "3" ,
month    =    "sep" ,
year    =    "1988" ,
pages    =    "183--205" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( DEMOLOMBE91,
key    =    "Demolombe" ,
author    =    "Demolombe, R." ,
title    =    "An Efficient Strategy for non-{H}orn Deductive
Databases" ,
year    =    "1991" ,
journal    =    "Theoretical Computer Sciences" ,
volume    =    "78" ,
pages    =    "245--259" ,
number    =    "1" ,
month    =    "jan" ,
)

@techreport    ( DESHPANDE87,
key    =    "Deshpande \& Larson" ,
author    =    "Deshpande and Larson" ,
title    =    "An Algebra for Nested Relations with support for
nulls and aggregates" ,
type    =    "Research Report" ,
number    =    "CS-91-16" ,
institution=    "University of Waterloo, Canada" ,
year    =    "1987" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( DICESARE90,
key    =    "DiCesare \& Sahnoun" ,
author    =    "DiCesare, F. and Sahnoun, Z." ,
title    =    "Linguistic Summarization of Fuzzy Data" ,
journal    =    "Information Services" ,
volume    =    "52" ,
year    =    "1990" ,
pages    =    "141--152" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( DIGNUM92,
key    =    "Dignum \& Riet" ,
author    =    "Dignum, F. and van de Riet, R. P." ,
title    =    "Addition and removal of information for a
knowledge base with incomplete information" ,
journal    =    "Data \& Knowledge Engineering" ,
volume    =    "8" ,
year    =    "1992" ,
pages    =    "293--307" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( DOCKERY89,
key    =    "Dockery \& Murray" ,
author    =    "Dockery, J. T. and Murray, E." ,
title    =    "Fuzzy linguistic data bases. An application." ,
journal    =    "Information Sciences" ,
volume    =    "14" ,
number    =    "6" ,
pages    =    "???--???" ,
year    =    "1989" ,
abstract=    " This paper discusses the empirical development
and use of a fuzzy linguistic data base which is relational in
character. Unlike conventional fuzzy searches for crisp data, we
search a data base for fuzzy information. The data base supports
another code which does fuzzy aggregation of data. It has been applied
to support decision making connected with the construction of military
budgets for command, control and communications (C3). " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@phdthesis    ( DREIZEN83,
key    =    "Dreizen" ,
author    =    "Dreizen, H. M." ,
title    =    "Imprecise Database: Representation of Imprecise
and Exceptional Conditions via Embedded Relations" ,
school    =    "University of Illinois" ,
address    =    "Chicago, IL" ,
year    =    "1983" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( DREIZEN85,
key    =    "Dreizen \& Chang" ,
author    =    "Dreizen, H. M. and Chang, S. K." ,
title    =    "Imprecise Database: Imprecise Queries and View
Navigation" ,
journal    =    "Inf. Sci. Eng. 1" ,
volume    =    "1" ,
month    =    "jan" ,
year    =    "1985" ,
pages    =    "12--43" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( DREIZEN89,
key    =    "Dreizen \& Chang" ,
author    =    "Dreizen, H. M. and Chang, S. K." ,
title    =    "Imprecise Schema: A Rationale for Relations with
Embedded Subrelations" ,
journal    =    "tods" ,
volume    =    "14" ,
number    =    "4" ,
month    =    "dec" ,
year    =    "1989" ,
pages    =    "447--479" ,
keywords=    "embedded subrelations; exceptional conditions;
imprecise schema; non-1NF; null values" ,
abstract=    "Exceptional conditions are anomalous data which
meet the intent of a schema but not the schema definition, represent a
small proportion of the database extension, and may become known only
after the schema is in use. Admission of exceptional conditions is
argued to suggest a representation that locally stretches the schema
definition by use of relations with embedded subrelations. Attempted
normalization of these relations to 1NF does not yield the static
schema typically associated with such transformations. A class of
relations, termed Exceptional Condition Nested Form (ECNF), is defined
which allows the necessary representation of exceptional conditions
while containing sufficient restrictions to prevent arbitrary and
chaotic inclusion of embedded subrelations. Queries on a subset of
exceptional conditions, the exceptional constraints, are provided an
interpretation via an algorithm that transforms ECNF relations into
1NF relations containing two types of null values. Extensions of
relational algebraic operators, suitable for interactive query
navigation, are defined for use with ECNF relations containing all
forms of exceptional conditions." ,
bibdate    =    "Thu Feb  1 14:11:40 1990" ,
owner    =    "robyn" ,
)

@book        ( DUBOIS80,
key    =    "Dubois \& Prade" ,
author    =    "Dubois, D. and Prade, H." ,
title    =    "Fuzzy Sets and Systems: Theory and Applications" ,
publisher=    "Academic Press" ,
address    =    "New York, NY" ,
year    =    "1980" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inbook        ( DUBOIS88,
key    =    "Dubois et al." ,
author    =    "Dubois, D. and Prade, H. and Testamale, C." ,
title    =    "Handling Incomplete or Uncertain Data and Vague
Queries in Database Applications" ,
booktitle=    "Possibility Theory: An Approach to Computerized
Processing of Uncertainty" ,
publisher=    "Plenum Press" ,
address    =    "New York and London" ,
year    =    "1988" ,
chapter    =    "6" ,
pages    =    "217--257" ,
abstract=    "We examine the question of null values in a
database system. We begin by defining the term ``null value'' and
outlining the problems that null values are intended to solve. We go
on to discuss the properties of null values in detail, and describe
some extensions to the relational model for dealing with such values.
We then discuss some of the difficulties that occur in connexion with
the null value concept. It is our opinion that the problem is
generally not well understood, and that any attempt to incorporate
support for null values into an implemented system should be
considered premature at this time. We sketch an alternative approach
based on the concept of default values." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( DUBOIS88A,
key    =    "Dubois \& Prade" ,
author    =    "Dubois, D. and Prade, H." ,
title    =    "Incomplete conjunctive information" ,
journal    =    "Computers \& Mathematics with Applications" ,
volume    =    "15" ,
number    =    "10" ,
year    =    "1988" ,
pages    =    "797--810" ,
abstract=    "do not have article QA 76 C5364" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( DUBOIS89,
key    =    "Dubois \& Prade" ,
author    =    "Dubois, D. and Prade, H." ,
title    =    "Processing Fuzzy Temporal Knowledge" ,
journal    =    "IEEE Transactions of Systems, Man and Cybernetics" ,
volume    =    "19" ,
number    =    "4" ,
year    =    "1989" ,
pages    =    "729--744" ,
abstract=    "TA 168 I216 BOON" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( DUBOIS90,
key    =    "Dubois \& Prade" ,
author    =    "Dubois, D. and Prade, H." ,
title    =    "Measuring properties of fuzzy sets: a general
technique and its use in fuzzy query evaluation." ,
journal    =    "Fuzzy Sets and Systems" ,
volume    =    "38" ,
number    =    "2" ,
year    =    "1990" ,
pages    =    "137--152" ,
abstract=    " Summary: A fuzzy set can be viewed as a
weighted-max combination or as a convex combination of a family of
nested ordinary sets. The latter point of view allows the
interpretation of a fuzzy set as a consonant random set. Then any
numerical set function applied to a fuzzy set leads to a result which
is a random number. The expectation attached to this random number
provides a scalar evaluation of the fuzzy set with respect to the
considered set function. This approach is very general and can be used
for various kinds of measurements: cardinality, confidence measures
attached to the occurrence of events, diameter or perimeter of a fuzzy
region, distance between two sets, etc. Also the fuzziness of the set
to be evaluated naturally induces a fuzzy set of possible evaluations,
and expected values of the lower and upper bounds of this fuzzy set of
numbers can be computed. The weighted max-combination view, which
leads to another type of scalar evaluation, is also briefly discussed.
In this paper the approach above is more particularly applied to the
treatment of queries asking for some global evaluation of a set of
items specified by means of a fuzzy property. This kind of query can
be managed by languages SQL in the case of a crisp set of items. When
this set is fuzzily specified, a scalar answer can still be provided
as well as a fuzzy-valued or interval-valued one if we want to keep
track of the effect of the fuzziness of the query. The case where the
data base contains precise information is considered, as well as the
more general case of fuzzy information data bases. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( DUTTA88A,
key    =    "Dutta" ,
author    =    "Dutta, S." ,
title    =    "Approximate spatial reasoning" ,
booktitle=    "Fourth Conference on Artificial Intelligence for
Space Applications" ,
address    =    "Huntsville, AL" ,
month    =    "nov" ,
year    =    "1988" ,
pages    =    "95--106" ,
abstract=    " We present a model for approximate spatial
reasoning using fuzzy logic to represent the imprecision in the
environment. We develop algorithms to reason from approximate spatial
information such as: A is about 5 miles away and is coming towards me
quite fast. B is quite near C, but is far north of D. B is moving much
faster than C. The kind of spatial information dealt with has two
notable characteristics: it is approximate and may be incomplete. We
present algorithms for determining approximate relative positions of
objects, in both static and dynamic domains. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( DUTTA88B,
key    =    "Dutta" ,
author    =    "Dutta, S." ,
title    =    "An Event-based Fuzzy Temporal Logic" ,
booktitle=    "Proc. 18th IEEE Intl. Symp. on Multiple-Valued
Logic" ,
address    =    "Palma de Mallorca, Spain" ,
year    =    "1988" ,
pages    =    "64--71" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( DUTTA89,
key    =    "Dutta" ,
author    =    "Dutta, S." ,
title    =    "Generalized Events in Temporal Databases" ,
booktitle=    "Proceedings of the Fifth International Conference
on Data Engineering" ,
address    =    "Los Angeles, CA" ,
month    =    "feb" ,
year    =    "1989" ,
pages    =    "118--126" ,
abstract=    "The concept of time plays a central role in our
lives. Thus it comes as no surprise that the effective representation
and manipulation of temporal data is currently an active area of
research in databases. In this paper, we distinguish between the
concepts of temporal entities and temporal events and extend the
conventional crisp notion of events to define generalized events. We
also note that there are two broad categories of temporal operators,
those which operate on temporal entities and those which operate on
temporal events. We provide new definitions for temporal operators
used for generalized events. We choose a temporal data model which is
independent of conventional data models, but is similar to temporal
data models proposed by other researchers and is sufficiently general
to be applied to suitable extensions of conventional data models. We
show how to combine different generalized events and apply temporal
operators to such compound events. An outline of a possible
implementation of our ideas in the relational data model is also
provided." ,
bibdate    =    "Fri Jan 12 09:59:23 1990" ,
owner    =    "robyn" ,
)

@phdthesis    ( DUTTA90,
key    =    "Dutta" ,
author    =    "Dutta, S." ,
title    =    "Approximate Reasoning with Temporal and Spatial
Concepts" ,
school    =    "University of California, Berkeley" ,
address    =    "Berkeley, CA" ,
month    =    "may" ,
year    =    "1990" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( DYRESON91A,
key    =    "Dyreson \& Snodgrass" ,
author    =    "Dyreson, C. E. and Snodgrass, R. T." ,
title    =    "Temporal Indeterminacy" ,
type    =    "Technical Report" ,
number    =    "TR 91-30" ,
institution=    "uazcsd" ,
year    =    "1991" ,
month    =    "Dec." ,
pages    =    "31" ,
abstract=    "In temporal indeterminacy, it is known that an
event stored in a temporal database did in fact occur, but it is not
known exactly when the event occurred. We present the possible tuples
data model, in which each indeterminate event is represented with an
interval that delimits when the event might have occurred, and a
probability distribution over that interval. We extend the TQuel query
language with constructs that specify the user's confidence in the
underlying temporal data and in the relationships among that data. We
provide a formal tuple calculus semantics, and show that this
semantics reduces to the determinate semantics. We outline an
efficient representation of temporal indeterminacy, and efficient
query processing algorithms, demonstrating the practicality of our
proposed approach." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( DYRESON92A,
key    =    "Dyreson et al." ,
author    =    "Dyreson, C. E. and Snodgrass, R. T. and Jensen, C.
S." ,
title    =    "A Taxonomy of Incomplete Information in Databases" ,
type    =    "unpublished" ,
number    =    "" ,
institution=    "uazcsd" ,
year    =    "1992" ,
month    =    "jun" ,
abstract=    "none yet" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( DYRESON92B,
key    =    "Dyreson \& Snodgrass" ,
author    =    "Dyreson, C. E. and Snodgrass, R. T." ,
title    =    "Historical Indeterminacy" ,
type    =    "Technical Report" ,
number    =    "TR 91-30a" ,
institution=    "uazcsd" ,
year    =    "1992" ,
month    =    "Revised Feb." ,
pages    =    "31" ,
abstract=    "In temporal indeterminacy, it is known that an
event stored in a temporal database did in fact occur, but it is not
known exactly when the event occurred. We present the possible tuples
data model, in which each indeterminate event is represented with an
interval that delimits when the event might have occurred, and a
probability distribution over that interval. We extend the TQuel query
language with constructs that specify the user's confidence in the
underlying temporal data and in the relationships among that data. We
provide a formal tuple calculus semantics, and show that this
semantics reduces to the determinate semantics. We outline an
efficient representation of temporal indeterminacy, and efficient
query processing algorithms, demonstrating the practicality of our
proposed approach." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( DYRESON93A,
key    =    "Dyreson \& Snodgrass" ,
author    =    "Dyreson, C. E. and Snodgrass, R. T." ,
title    =    "Valid-Time Indeterminacy" ,
booktitle=    "Proceedings of the International Conference on
Data Engineering" ,
address    =    "Vienna, Austria" ,
month    =    "apr" ,
pages    =    "335--343" ,
year    =    "1993" ,
bibdate    =    "Thu Oct 22 10:29:43 1992" ,
owner    =    "rts" ,
)

@techreport    ( DYRESON93K,
key    =    "Dyreson \& Snodgrass" ,
author    =    "Dyreson, C. E. and Snodgrass, R. T." ,
title    =    "Supporting Valid-time Indeterminacy" ,
type    =    "Technical Report" ,
number    =    "TR 93-30" ,
institution=    "uazcsd" ,
year    =    "1993" ,
month    =    "Nov." ,
pages    =    "52" ,
abstract=    "" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( DYRESON93Z,
key    =    "Dyreson" ,
author    =    "Dyreson, C." ,
title    =    "A Bibliography on Uncertainty Management in
Information Systems" ,
booktitle=    "Proceedings of the Workshop on Uncertainty
Management in Information Systems: From Needs to Solutions" ,
address    =    "Avalon, Santa Catalina, California" ,
month    =    "apr" ,
year    =    "1993" ,
pages    =    "187--220" ,
abstract=    "" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( EASTMAN87,
key    =    "Eastman" ,
author    =    "Eastman, C. M." ,
title    =    "Approaches to Approximate Retrieval in Database
Management Systems" ,
booktitle=    "NAFIPS 87: Proceedings of the North American Fuzzy
Information Processing Society Workshop" ,
month    =    "may" ,
year    =    "1987" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( EASTMAN89,
key    =    "Eastman" ,
author    =    "Eastman, C. M." ,
title    =    "Approximate Retrieval: A Comparison of Information
Retrieval and Database Management Systems" ,
journal    =    "IEEE Database Engineering Bulletin - Special Issue
on Imprecision in Databases" ,
volume    =    "12" ,
number    =    "2" ,
month    =    "jun" ,
year    =    "1989" ,
pages    =    "41--45" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( ESCULIER90,
key    =    "Esculier" ,
author    =    "Esculier, C." ,
title    =    "Non-Monotonic Knowledge Evolution in VLKDBs" ,
booktitle=    "Proc. of the 16th Conf. on Very Large Databases
(VLDB'90)" ,
address    =    "Brisbane, Australia" ,
year    =    "1990" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@book        ( FLEISCHMAN91,
key    =    "Fleischman" ,
author    =    "Fleischman, R. M." ,
title    =    "Supporting Fuzzy Logic Selection Predicates on a
High Throughput Database System" ,
publisher=    "MIT Library" ,
address    =    "Boston, MA" ,
year    =    "1991" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( FUHR90,
key    =    "Fuhr" ,
author    =    "Fuhr, N." ,
title    =    "A Probabilistic Framework for Vague Queries and
Imprecise Information in Databases" ,
booktitle=    "vldb" ,
address    =    "Brisbane, Australia" ,
year    =    "1990" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( GADIA91A,
key    =    "Gadia et al." ,
author    =    "Gadia, S. K. and Nair, S. and Poon, Y.-C." ,
title    =    "Incomplete Information in Relational Temporal
Databases" ,
number    =    "Technical Report" ,
institution=    "Department of Computer Science, Iowa State
University" ,
address    =    "Ames, IA" ,
year    =    "1991" ,
month    =    "dec" ,
abstract=    "We present a model and an algebra for incomplete
information in temporal databases. The model generalizes our previous
model for a temporal database for complete information. It is shown
that our relational operators produce results that are reliable. We
also show, with some minor exceptions, that if the definitions of the
operators were strengthened to give more information, we may obtain
results that are not reliable. These results and exceptions parallel
Biskup`s findings for relational databases with incomplete
information." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( GADIA92A,
key    =    "Gadia et al." ,
author    =    "Gadia, S. K. and Nair, S. and Poon, Y.-C." ,
title    =    "Incomplete Information in Relational Temporal
Databases" ,
booktitle=    "vldb" ,
address    =    "Vancouver, Canada" ,
month    =    "aug" ,
year    =    "1992" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( GALA91,
key    =    "Gala et al." ,
author    =    "Gala, S. and Chawala, D. and Eastman, C." ,
title    =    "Combining Fuzzy and Nonfuzzy Approximate Retrieval
in a Database Management System" ,
booktitle=    "NAFIPS 91 Proceedings of the North American Fuzzy
Information Processing Society Workshop" ,
month    =    "may" ,
year    =    "1991" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( GALLAIRE84,
key    =    "Gallaire et al." ,
author    =    "Gallaire, H. and Minker, J. and Nicolas, J. M." ,
title    =    "Logic and databases: A deductive approach" ,
journal    =    "ACM Computing Surveys" ,
volume    =    "16" ,
number    =    "2" ,
month    =    "jun" ,
year    =    "1984" ,
pages    =    "153--185" ,
keywords=    "Deductive Databases, Indefinite Data, Logic and
Databases, Null Values, Relational Databases" ,
abstract=    "The purpose of this paper is to show that logic
provides a convenient formalism for studying classical database
problems. There are two main parts to the paper, devoted respectively
to conventional databases and deductive databases. In the first part,
we focus on query languages, integrity modeling and maintenance, query
optimization, and data dependencies. The second part deals mainly with
the representation and manipulation of deduced facts and incomplete
information." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( GARCIA-MOLINA88,
key    =    "Garcia-Molina \& Porter" ,
author    =    "Garcia--Molina, H. and Porter, D." ,
title    =    "Supporting Probabilistic Data in a Relational
System" ,
type    =    "TR" ,
number    =    "147--88" ,
institution=    "Princeton University" ,
year    =    "1988" ,
month    =    "feb" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( GELENBE83A,
key    =    "Gelenbe" ,
author    =    "Gelenbe, E." ,
title    =    "Incomplete representations of information in data
bases" ,
type    =    "Research Report" ,
number    =    "No 9" ,
institution=    "ISEM, Univ. Paris-Sud" ,
year    =    "1983" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( GELENBE83B,
key    =    "Gelenbe" ,
author    =    "Gelenbe, E." ,
title    =    "Incomplete Representation of Information in
Databases" ,
booktitle=    "ICOD-2 Proceedings of the Second International
Conference on Databases" ,
address    =    "Cambridge, England" ,
month    =    "aug" ,
year    =    "1983" ,
pages    =    "246--258" ,
abstract=    "do not have article QA76.9.D3 I25 1983" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( GELENBE86,
key    =    "Gelenbe \& Hebrail" ,
author    =    "Gelenbe, E. and Hebrail, G." ,
title    =    "A Probability Model of Uncertainty in Data Bases" ,
booktitle=    "Proceedings of the International Conference on
Data Engineering" ,
organization=    "IEEE Computer Society" ,
publisher=    "IEEE Computer Society Press" ,
address    =    "Los Angeles, CA" ,
volume    =    "IEEE Computer Society Order Number 655" ,
month    =    "feb" ,
year    =    "1986" ,
pages    =    "328--333" ,
abstract=    "Uncertainty in the contents of a data base can be
due to several reasons: errors in the data which is entered, changes
in the real data which have not been introduced into the data base in
the form of updates, errors in the data collection process, unreliable
operation of the computer system, don't care conditions which are
purposely left open by the data base designer, etc. The purpose of
this paper is to present a formal model of uncertainty in terms of a
probabilistic representation of the data base, and to evaluate the
effect of this uncertainty on query processing and on the aggregate or
summary information which may suffice in many applications. Our model
leads to precise quantifiable engineering estimates and to theorems on
the robustness of answers to queries as a function of the uncertainty
in the data." ,
bibdate    =    "Wed Jul 16 15:24:20 1986" ,
owner    =    "manning" ,
)

@inproceedings    ( GELFOND91,
key    =    "Gelfond et al." ,
author    =    "Gelfond, M. and Lifschitz, V. and Przymusi\'{n}ka,
H. and Truszczy\'{n}ski, M." ,
title    =    "Disjunctive Defaults" ,
booktitle=    "Proc. of 2nd Int. Conf. Principles of Knowledge
Representation and Reasoning KR'91" ,
address    =    "Cambridge, MA" ,
month    =    "apr" ,
year    =    "1991" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( GEORGE92,
key    =    "George et al." ,
author    =    "George, R. and Yazici, A. and Petry, F. E. and
Buckles, B. P." ,
title    =    "Uncertainty Modeling in Object-Oriented
Geographical Information Systems" ,
booktitle=    "Proc. Int. Conf. on Database and Expert Systems
Applications (DEXA'92)" ,
address    =    "Valencia, Spain" ,
year    =    "1992" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( GESSERT90,
key    =    "Gessert" ,
author    =    "Gessert, G. H." ,
title    =    "Four Value Logic for Relational Database Systems" ,
journal    =    "sigmod" ,
volume    =    "19" ,
number    =    "1" ,
year    =    "1990" ,
pages    =    "29--35" ,
bibdate    =    "Sun Apr  7 17:11:20 1991" ,
owner    =    "curtis" ,
abstract=    "This paper proposes a specific four-valued logic
(4VL) as a means of handling missing data in Relational Data Base
Management systems. The proposed 4VL is a minor variant of the
standard 4VL in which the ``least true'' condition is interpreted as
``inapplicable'' rather that ``false''. The use of this 4VL is
defended on the grounds that by defining several additional unary
operators, the 4VL can be rendered intuitively manageable. The
proposed unary operators contribute to the conceptual utility of the
4VL by providing an explicit way for users to relate familiar results
of two-valued logic to analogous results in 4VL." ,
)

@article    ( GESSERT91,
key    =    "Gessert" ,
author    =    "Gessert, G. H." ,
title    =    "Handling Missing Data by Using Stored Truth Values" ,
journal    =    "sigmod" ,
publisher=    "ACM" ,
volume    =    "20" ,
number    =    "3" ,
month    =    "sep" ,
year    =    "1991" ,
pages    =    "30--42" ,
abstract=    "This paper proposes a method for handling
inapplicable and unknown missing data. The method is based on: (1)
storing default values (instead of null values) in place of missing
data, (2) storing truth values that describe the logical status of the
default values in corresponding fields of corresponding tables. For
valued logic is used so that the logical status of the default data
values can be described as, not just true or false, but also as
inapplicable or unknown. This method, in contrast to the ``hidden
byte'' approach, has two important advantages: (1) Because the logical
status of all data is represented explicitly in tables, all 4-valued
operations can be handled via a 2-valued data manipulation language,
such as SQL. Language extensions for handling missing data (e.g., ``Is
NULL'') are not necessary. (2) Because data fields always contain a
default value (as opposed to a null value or mark), it is possible to
do arithmetic across missing data and to interpret the logical status
of the result by means of logical operations on the corresponding
stored truth values." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( GOLDSTEIN81,
key    =    "Goldstein" ,
author    =    "Goldstein, B." ,
title    =    "Constraints on Null Values in Relational Databases" ,
booktitle=    "vldb" ,
address    =    "Cannes, France" ,
month    =    "sep" ,
year    =    "1981" ,
pages    =    "101--110" ,
abstract=    "If null values are allowed in a database, the
database designer may want to restrict where they occur. Two
constructs are presented for specifying where null values may occur in
a relational database. Several examples demonstrate the use of these
two techniques. The two constructs are shown to be almost equivalent;
a criterion for exact equivalence is given. Under the same criterion,
interesting special cases of both constructs are also shown to be
equivalent." ,
bibdate    =    "Sun Apr  7 17:11:20 1991" ,
owner    =    "curtis" ,
)

@article    ( GOLSHANI85,
key    =    "Golshani" ,
author    =    "Golshani, F." ,
title    =    "Growing Certainty With Null Values" ,
journal    =    "Information Systems" ,
volume    =    "10" ,
number    =    "2" ,
year    =    "1985" ,
pages    =    "289--297" ,
keywords=    "database query language; incomplete information;
many-sorted algebra; many-valued logic; approximation" ,
abstract=    "Non-availability of part of the data is a problem
common to many database systems. We study here some aspects relating
to incomplete information. Obviously, when the information in a
database is not complete the answer to any query is only an
approximation to the true result. The aim is to get a precise
approximation. We regard databases as many-sorted algebras. Based on
the concept of extended algebra we define what it means for an algebra
to approximate another algebra. We then give the following simple
principle for extending query languages to handle missing data:
``Whenever information is added to an incomplete database subsequent
answers to queries must not be contradictory or less informative than
previously.'' We then apply this principle to extend the functional
query language Varqa. Finally, we compare the previously proposed
many-valued logic systems with the system devised based on our
principles." ,
bibdate    =    "Mon Oct 14 11:53:04 1985" ,
)

@book        ( GOODMAN85,
key    =    "Goodman \& Nguyen" ,
author    =    "Goodman, I. R. and Nguyen, H. T." ,
title    =    "Uncertainty Models for Knowledge-Based Systems" ,
publisher=    "North-Holland" ,
address    =    "Amsterdam" ,
year    =    "1985" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( GOTTLOB88,
key    =    "Gottlob \& Zicari" ,
author    =    "Gottlob, G. and Zicari, R." ,
title    =    "Closed World Databases Opened Through Null Values" ,
booktitle=    "vldb" ,
address    =    "Los Angeles, CA" ,
year    =    "1988" ,
pages    =    "50--61" ,
abstract=    "We propose a new approach to the treatment of
null-valued attributes in the relational model. The approach is based
on the new concept of locally-controlled open world database. A
locally-controlled open world database permits the definition of
portions of a traditional closed world database as open-world.
Attributes, part of a relation, or entire relations can be explicitly
defined as ``open'' through the insertion of null-values. Under this
assumption, we consider three different types of null values: the
standard {\em unknown}, {\em does not exist}, and the new one, called
{\em open}. We give a complete formal specification of the semantics
of these null values. We extend the arithmetic and logical operators
to cover nulls and outline how relational operators can be extended
accordingly. This paper describes ongoing work. We state some open
problems to be solved in order to render our approach more
operational." ,
bibdate    =    "Wed Jul 31 21:42:40 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( GRAHNE84,
key    =    "Grahne" ,
author    =    "Grahne, G." ,
title    =    "Dependency Satisfaction in Databases with
Incomplete Information" ,
booktitle=    "vldb" ,
address    =    "Singapore" ,
month    =    "aug" ,
year    =    "1984" ,
pages    =    "37--45" ,
abstract=    "Two of the major problems raised by information
incompleteness in databases are how to evaluate queries and how to
take data dependencies into account. We give a unified solution of
these two intermingled problems for the relational model. Formal
criteria for the correctness of the relational algebra and dependency
satisfaction are presented. We give a correct definition of the
complete relational algebra and present a method, called a chase, for
enforcing a set of functional and full join dependencies on a relation
with null-values of type ``value exists, but is presently unknown''.
This novel chase can also be regarded as a generalization of
previously known chase methods. The title of the paper reflects the
emphasis of its contribution." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( GRAHNE89A,
key    =    "Grahne" ,
author    =    "Grahne, G." ,
title    =    "Horn tables - an efficient tool for handling
incomplete information in databases" ,
booktitle=    "sigmod" ,
address    =    "Philadelphia, PA" ,
month    =    "mar" ,
year    =    "1989" ,
pages    =    "75--82" ,
abstract=    "The basic semantic assumption is that an
incomplete information database is a set of possible worlds (i.e. a
set of complete databases). The main issue is then the problem of
representing the set of possible worlds in a fashion that is suitable
for storing and processing the database. We have complemented the
representation hierachy with a construct called Horn tables. The class
of Horn tables is algebraically closed under any set of total
dependencies, and it is the only class in the hierarchy with this
property (apart from the top elements in the hierachy, which is of
theoretical interest only). All sets of dependencies consisting of
equality generating dependencies and one join dependency can be
efficiently incorporated into a Horn table. The certain answer to any
datalog query can be evaluated in polynomial time in the size of the
Horn table. The same is true for the possible answer to any positive
existential query. If one is concerned only with certain answers to
datalog queries, any set of dependencies can be efficiently
incorporated into a Horn table so that no corruption of the
information occurs w.r.t. the answers. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@phdthesis    ( GRAHNE89B,
key    =    "Grahne" ,
author    =    "Grahne, G." ,
title    =    "The Problem of Incomplete Information in
Relational Databases" ,
year    =    "1989" ,
month    =    "mar" ,
school    =    "University of Helsinki, Finland" ,
)

@article    ( GRANT77,
key    =    "Grant" ,
author    =    "Grant, J." ,
title    =    "Null Values in a Relational Data Base" ,
journal    =    "Information Processing Letters" ,
volume    =    "6" ,
number    =    "5" ,
month    =    "Oct" ,
year    =    "1977" ,
pages    =    "156--157" ,
keywords=    "Information systems, relational data base" ,
abstract=    "none" ,
bibdate    =    "Wed Jul 31 21:42:40 1991" ,
owner    =    "curtis" ,
)

@article    ( GRANT79,
key    =    "Grant" ,
author    =    "Grant, J." ,
title    =    "Partial Values in a Tabular Database Model" ,
journal    =    "Information Processing Letters" ,
volume    =    "9" ,
number    =    "2" ,
month    =    "Aug" ,
year    =    "1979" ,
pages    =    "97--99" ,
keywords=    "Partial values, relational database" ,
abstract=    "none" ,
bibdate    =    "Wed Jul 31 21:42:40 1991" ,
owner    =    "curtis" ,
)

@article    ( GRANT80A,
key    =    "Grant" ,
author    =    "Grant, J." ,
title    =    "Incomplete Information in a Relational Database" ,
journal    =    "Fundamenta Informatic\ae" ,
volume    =    "III" ,
number    =    "3" ,
year    =    "1980" ,
pages    =    "363--378" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@incollection    ( GRANT86,
key    =    "Grant \& Minker" ,
author    =    "Grant, J. and Minker, J." ,
title    =    "Answering queries in indefinite databases and the
null value problem" ,
booktitle=    "Advances in Computing Research" ,
editor    =    "P. Kanellakis" ,
publisher=    "JAI Press" ,
address    =    "London" ,
year    =    "1986" ,
volume    =    "3" ,
pages    =    "247--267" ,
abstract=    "We investigate the notion of answering queries for
databases that may contain indefinite data. Such indefinite data is
represented as a disjunctive formula in first-order logic. We work
within a framework of database theories which contains the domain
closure axiom, the unique name axioms, and the equality axioms. In
addition, for negative information we use a Generalized Closed World
Assumption. Queries are also formulas in first-order logic, while
possible answers are disjunctions of tuples. We give an algorithm to
check if a candidate answer is in fact an answer. We also develop an
algorithm to find all minimal answers to a query. We show how the
problem of null values can be investigated as a special case of
incomplete information." ,
bibdate    =    "Wed Jul 31 21:42:40 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( GUNTZER91,
key    =    (G\"{u}ntzer et al.) ,
author    =    (G\"{u}ntzer, U. and Kiessling, W. and Th\"{o}ne,
H.) ,
title    =    "New Directions for Uncertainty Reasoning in
Deductive Databases" ,
booktitle=    "sigmod" ,
address    =    "Denver, CO" ,
month    =    "may" ,
year    =    "1991" ,
pages    =    "178--187" ,
abstract=    "This paper contributes a novel approach to
nonmontonic uncertainty reasoning, which is ubiquitous in many
real-life applications. Founded on the paradigm of conditional
probabilities we develop a rule-based calculus and prove that it is
sound, even in the presence of incomplete information. Thus the merits
of doing consistent judgements in uncertain domains and the advantages
of modularity and incrementality of rule-based application development
come together. We also can offer mechanisms to trace down collections
of uncertain rules. As next-generation applications will have to
handle vast amounts of uncertain data, an integration into databases
is mandatory. We give a direct implementation of our calculus on top
of a database system with a DATALOG-interface. In this way we extend
current database technology towards providing new applications with
new suitable primitives and with a database platform for coping with
uncertainty." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( HAAR77,
key    =    "Haar" ,
author    =    "Haar, R. L." ,
title    =    "A fuzzy relational data base system" ,
number    =    "TR-586" ,
institution=    "University of Maryland, Computer Center" ,
year    =    "1977" ,
month    =    "sep" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( HAVRANEK80,
key    =    "Havr\'{a}nek" ,
author    =    "Havr\'{a}nek, T." ,
title    =    "An Alternative Approach to Missing Information in
the GUHA Method" ,
journal    =    "Kybernetika (Prague)" ,
volume    =    "16" ,
number    =    "22" ,
year    =    "1980" ,
pages    =    "145--155" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( HAWKES90,
key    =    "Hawkes et al." ,
author    =    "Hawkes, L. W. and Derry, S. J. and Rundensteiner,
E. A." ,
title    =    "Individualized tutoring using an intelligent fuzzy
temporal relational database" ,
journal    =    "International Journal on Man-Machine Studies" ,
volume    =    "33" ,
number    =    "4" ,
year    =    "1990" ,
pages    =    "409--429" ,
abstract=    "The student record (SR) is a major source of input
for any decision making done by an Intelligent Tutoring System (ITS)
and is a basis of the individualization in such systems. However, most
ITSs still have ``generalized'' student models which represent a type
of student rather than a particular one. Until the SR becomes truly
representative of each individual student, the goal of providing
individualized tutoring cannot be attained. In this paper we describe
an Intelligent Fuzzy Temporal Relational Database (IFTReD), an
intelligent system-independent SR which allows for almost any degree
of individualization the designer wishes to incorporate. It is
anticipated that this IFTReD will provide a significant improvement
over standard AI storage techniques for the SR. These improvements
will be realized in terms of: (1) intelligence; (2) greater storage
efficiency; (3) greater speed in retrieval and query; (4) ability to
handle linguistic codes, ranges, fuzzy possibilities, and incomplete
data in student models; (5) friendliness of query language; (6)
availability of temporal knowledge to give a history of past
performance; and (7) a more holistic view of the student permitting
greater individualization of the tutor." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( HEGNER87,
key    =    "Hegner" ,
author    =    "Hegner, S." ,
title    =    "Specification and implementation of programs for
updating incomplete information databases" ,
booktitle=    "pods" ,
address    =    "San Diego, CA" ,
month    =    "mar" ,
year    =    "1987" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( HENRION93,
key    =    "Henrion \& Suermondt" ,
author    =    "Henrion, M. and Suermondt, J." ,
title    =    "Probabilistic and Bayesian Representations of
Uncertainty and Information Systems: A Pragmatic Introduction" ,
booktitle=    "Proceedings of the Workshop on Uncertainty
Management in Information Systems: From Needs to Solutions" ,
address    =    "Avalon, Santa Catalina, California" ,
month    =    "apr" ,
year    =    "1993" ,
pages    =    "71--90" ,
abstract=    "" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@incollection    ( HENSCHEN86,
key    =    "Henschen \& Park" ,
author    =    "Henschen, L. J. and Park, H. S." ,
title    =    "Compiling the GCWA in indefinite deductive
databases" ,
booktitle=    "Foundations of Deductive Databases and Logic
Programming" ,
editor    =    "J. Minker" ,
publisher=    "M. Kaufmann" ,
address    =    "Los Altos, CA" ,
year    =    "1986" ,
pages    =    "395--438" ,
abstract=    "This paper presents several fundamental results on
compiling the GCWA (Generalized Closed World Assumption) in IDDB
(Indefinite Deductive Databases). We do not allow function symbols,
but we do allow non-Horn clauses. Further, although the GCWA is used
to derive negative assumptions, we do allow also negative clauses to
occur explicitly. We show a fundamental relationship between
indefiniteness and GCWA inference. We consider three representation
alternatives to separate the CDB (Clausal DB) from the RDB (Relational
DB). We present the basic ideas and some effective ways for compiling
GCWA inference on the CDB and evaluating it though the RDB in a
non-recursive IDDB. We also present a basic idea on compiling the GCWA
in a recursive IDDB by a pattern generation method. Finally, we
introduce decomposition and evaluation theorems to evaluate
disjunctive and conjunctive ground queries." ,
bibdate    =    "Wed Jul 31 21:42:40 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( HENSCHEN86A,
key    =    "Henschen \& Park" ,
author    =    "Henschen, L. J. and Park, H. S." ,
title    =    "Indefinite and GCWA Inference in Indefinite
Deductive Databases" ,
year    =    "1986" ,
pages    =    "191--197" ,
booktitle=    "Proc. AAAI-86" ,
)

@article    ( HOMENDA91,
key    =    "Homenda" ,
author    =    "Homenda, W." ,
title    =    "Databases with Alternative Information" ,
journal    =    "tkde" ,
publisher=    "IEEE" ,
volume    =    "3" ,
number    =    "3" ,
month    =    "sep" ,
year    =    "1991" ,
pages    =    "384--386" ,
abstract=    "A special kind of information-alternative
information-is considered in this work. Two different pieces of
information: I1 AND/OR I2 and EITHER I1 OR I2 are examples of
alternative information. Applicable models of data do not distinguish
information of this kind, but such a distinction, however, is
important in many circumstances. An attempt to distinguish and process
alternative information is made in this work." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( HULIN88C,
key    =    "Hulin" ,
author    =    "Hulin, G." ,
title    =    "A Proof-theoretic Perspective of Deductive
Databases with Marked Null Values" ,
year    =    "1988" ,
number    =    "M273" ,
institution=    "Phillips Research Laboratory, Brussels" ,
month    =    "dec" ,
type    =    "Manuscript" ,
)

@techreport    ( HULIN90B,
key    =    "Hulin" ,
author    =    "Hulin, G." ,
title    =    "Relational Databases with Marked Null Values: A
New Approach" ,
year    =    "1990" ,
number    =    "M333" ,
institution=    "Phillips Research Laboratory, Brussels" ,
month    =    "jan" ,
type    =    "Manuscript" ,
)

@techreport    ( HULL84,
key    =    "Hull" ,
author    =    "Hull, R." ,
title    =    "Relative Information Capacity of Simple Relational
Database Schemata" ,
type    =    "TR" ,
number    =    "84-300" ,
institution=    "Computer Science Department, The University of
Southern California" ,
year    =    "1984" ,
month    =    "jan" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( HURSON87,
key    =    "Hurson \& Miller" ,
author    =    "Hurson, A. and Miller, L." ,
title    =    "Database Machine Architecture for Supporting
Incomplete Information" ,
journal    =    "Computer Systems Science and Engineering" ,
volume    =    "2" ,
number    =    "3" ,
month    =    "jul" ,
year    =    "1987" ,
pages    =    "107--116" ,
abstract=    " A growing number of users require information
from the database that cannot be obtained through the operators found
in traditional query languages. Such needs have increased the
expectation that a system will be able to assist the user in gathering
and interpreting the appropriate data. This paper examines the
inclusion of maybe-algebra operators in a database machine. In
addition, modifications designed to increase the time and space
efficiency of the operators as well as the quality of the results are
discussed. Finally, a revised set of maybe-algebra operators offering
improved performance is introduced." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( ICHIKAWA86,
key    =    "Ichikawa \& Hirakawa" ,
author    =    "Ichikawa, T. and Hirakawa, M." ,
title    =    "ARES: a relational database with the capability of
performing flexible interpretation of queries" ,
journal    =    "tse" ,
volume    =    "12" ,
number    =    "5" ,
month    =    "may" ,
year    =    "1986" ,
pages    =    "624--634" ,
keywords=    "Data similarity, query
representation/transformation, relational algebra, relational
database, similarity graph, similarity relation" ,
abstract=    "As the social demand on database utilization
expands, database systems are being directly handled more and more by
nonprofessionals. In this field, it is important that friendly
user-interfaces are provided. It has been found that nonprocedural
ways of describing queries such as QBE are preferred. A further step
toward attaining a higher degree of user-friendliness would be the
development of a way of enabling the system to perform a flexible
interpretation of queries usually specified definitely by the user. A
flexible interpretation is necessary so that data items which are
semantically close to an exact match with the query conditions can be
obtained. This paper presents a relational database system, ARES,
which has the capability of performing a flexible interpretation of
queries. In ARES, relational operations have been functionally
augmented with an additional comparison operator which implies
''approximately equal to'' or ``similar to'' for cases in which the
user expects the system to perform a flexible interpretation of the
query conditions. The functional augmentation is simply achieved by a
combination of conventional relational operations. ARES is now in
actual operation in a research environment, and will contribute to the
next step of our research toward implementation of highly intelligent
data processing facilities beyond the present scope of database
technology." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( IMIELINSKI81,
key    =    "Imieli\'{n}ski \& Lipski" ,
author    =    "Imieli\'{n}ski, T. and Lipski, W., Jr." ,
title    =    "On Representing Incomplete Information in a
Relational Database" ,
booktitle=    "vldb" ,
address    =    "Cannes, France" ,
month    =    "sep" ,
year    =    "1981" ,
pages    =    "388--397" ,
abstract=    "Precise conditions are formulated which should be
satisfied in a semantically meaningful extension of the usual
relational operators of projection, selection, union, and join, from
operators on relations to operators on tables with ``null values'' of
various kinds allowed. These conditions require that our system be
safe in the sense that no incorrect conclusion is derivable by using a
specified subset $\Omega$ of the relational operators; and that it be
complete in the sense that all valid conclusions expressible by
relational expressions using operators in $\Omega$ are in fact
derivable in our system. Examples of three such systems are studied in
more detail. The effect of dependencies of various kinds is briefly
discussed." ,
bibdate    =    "Sun Apr  7 17:11:20 1991" ,
owner    =    "curtis" ,
)

@phdthesis    ( IMIELINSKI81A,
key    =    "Imieli\'{n}ski" ,
author    =    "Imieli\'{n}ski, T." ,
title    =    "Problems of representing information in relational
databases (in Polish)" ,
school    =    "Institute of Computer Science, Polish Academy of
Sciences" ,
year    =    "1981" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( IMIELINSKI83,
key    =    "Imieli\'{n}ski \& Lipski" ,
author    =    "Imieli\'{n}ski, T. and Lipski, W., Jr." ,
title    =    "Incomplete Information and Dependencies in
Relational Databases" ,
booktitle=    "sigmod" ,
address    =    "Orlando, FL" ,
month    =    "jun" ,
year    =    "1983" ,
pages    =    "178--184" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( IMIELINSKI84,
key    =    "Imieli\'{n}ski \& Lipski" ,
author    =    "Imieli\'{n}ski, T. and Lipski, W., Jr." ,
title    =    "Incomplete Information in Relational Databases" ,
journal    =    "jacm" ,
volume    =    "31" ,
number    =    "4" ,
year    =    "1984" ,
pages    =    "761--791" ,
keywords=    "Relational database, incomplete information, null
values, marked nulls, relational algebra, query language semantics,
query processing" ,
abstract=    "This paper concerns the semantics of Codd's
relational model of data. Formulated are precise conditions that
should be satisfied in a semantically meaningful extension of the
usual relational operators, such as projection, selection, union, and
join, from operators on tables with ``null values'' of various kinds
allowed. These conditions require that the system be safe in the sense
that no incorrect conclusion is derivable by using a specified subset
$\Omega$ of the relational operators; and that it be complete in the
sense that all conclusions expressible by relational expressions using
operators in $\Omega$ are in fact derivable in this system. Two such
systems of practical interest are shown. The first, based on the usual
Codd's null values, supports projection and selection. The second,
based on many different (``marked'') null values or variables allowed
to appear in a table, is shown to correctly support projection,
positive selection (with no negation occurring in the selection
condition), union, and renaming of attributes, which allows for
processing arbitrary conjunctive queries. A very desirable property
enjoyed by this system is that all relational operators on tables are
performed in exactly the same way as in the case of the usual
relations. A third system, mainly of theoretical interest, supporting
projection, selection, union, join, and renaming, is also discussed.
Under a so-called closed world assumption, it can also handle the
operator of difference. It is based on a device called a conditional
table and is crucial to the proof of the correctness of the second
system. All systems considered allow for relational expressions
containing arbitrarily many different relation symbols, and no form of
the universal relation assumption is required." ,
bibdate    =    "Mon Apr  1 15:18:35 1991" ,
owner    =    "curtis" ,
)

@incollection    ( IMIELINSKI84A,
key    =    "Imieli\'{n}ski" ,
author    =    "Imieli\'{n}ski, T." ,
title    =    "On Algebraic Query Processing in Logical Databases" ,
booktitle=    "Advances in Data Base Theory" ,
editor    =    "H. Gallaire and J. Minker and J.M. Nicolas" ,
publisher=    "Plenum Press" ,
address    =    "New York" ,
year    =    "1984" ,
volume    =    "2" ,
pages    =    "285--318" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( IMIELINSKI86A,
key    =    "Imieli\'{n}ski" ,
author    =    "Imieli\'{n}ski, T." ,
title    =    "Query Processing in Deductive Databases with
Incomplete Information" ,
type    =    "TR" ,
number    =    "177" ,
institution=    "Rutgers University" ,
year    =    "1986" ,
month    =    "mar" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( IMIELINSKI86B,
key    =    "Imieli\'{n}ski" ,
author    =    "Imieli\'{n}ski, T." ,
title    =    "Automated Deduction in Databases with Incomplete
Information" ,
type    =    "TR" ,
number    =    "181" ,
institution=    "Rutgers University" ,
year    =    "1986" ,
month    =    "mar" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( IMIELINSKI86C,
key    =    "Imieli\'{n}ski" ,
author    =    "Imieli\'{n}ski, T." ,
title    =    "Query Processing in Deductive Databases with
Incomplete Information" ,
booktitle=    "sigmod" ,
year    =    "1986" ,
pages    =    "268--280" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( IMIELINSKI86D,
key    =    "Imieli\'{n}ski" ,
author    =    "Imieli\'{n}ski, T." ,
title    =    "Automated Deduction in Databases with Incomplete
Information" ,
booktitle=    "Preprints of Workshop: Foundations of Deductive
Databases and Logic Programming" ,
year    =    "1986" ,
pages    =    "242--283" ,
address    =    "Washington, D.C." ,
month    =    "aug" ,
)

@inproceedings    ( IMIELINSKI89,
key    =    "Imieli\'{n}ski \& Vadaparty" ,
author    =    "Imieli\'{n}ski, T. and Vadaparty, K." ,
title    =    "Complexity of query processing in databases with
or-objects" ,
booktitle=    "pods" ,
year    =    "1989" ,
pages    =    "51--65" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( IMIELINSKI89A,
key    =    "Imieli\'{n}ski" ,
author    =    "Imieli\'{n}ski, T." ,
title    =    "Incomplete Information in Logical Databases" ,
journal    =    "IEEE Database Engineering Bulletin - Special Issue
on Imprecision in Databases" ,
volume    =    "12" ,
number    =    "2" ,
month    =    "jun" ,
year    =    "1989" ,
pages    =    "29--40" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@incollection    ( IMIELINSKI89B,
key    =    "Imieli\'{n}ski \& Lipski" ,
author    =    "Imieli\'{n}ski, T. and Lipski, W., Jr." ,
title    =    "Epilogue to `Incomplete Information in a
Relational Database'" ,
booktitle=    "Readings in Artificial Intelligence and Databases" ,
editor    =    "M.L. Brodie and J. Mylopoulos" ,
publisher=    "Springer-Verlag" ,
address    =    "Berlin and New York" ,
year    =    "1989" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( IMIELINSKI91,
key    =    "Imieli\'{n}ski et al." ,
author    =    "Imieli\'{n}ski, T. and Naqvi, S. and Vadaparty, K." ,
title    =    "Incomplete Objects---A Data Model for Design and
Planning Applications" ,
booktitle=    "sigmod" ,
address    =    "Denver, CO" ,
month    =    "may" ,
year    =    "1991" ,
pages    =    "288--297" ,
abstract=    "We are motivated by applications within design,
planning and scheduling areas, where current research appears to be
focused on syntactic issues of performance and volume. We take a more
semantic view of applications within these areas and discover several
useful functionalities that are poorly supported. For example,
facilities for handling incomplete specifications are quite
inadequate. We introduce a notion of OR-objects and show that it
captures incomplete specifications naturally. In particular a database
with OR-objects represents a set of possible worlds, e.g., a world for
each design or schedule, and queries can either be evaluated in the
``interpretations'' of the database, or in the database itself. We
formalize these notions of interpretations and hypothetical queries in
an object-oriented setting, and provide a complexity characterization
for our queries." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( IMIELINSKI91A,
key    =    "Imieli\'{n}ski et al." ,
author    =    "Imieli\'{n}ski, T. and Naqvi, S. and Vadaparty, K." ,
title    =    "Querying Design and Planning Databases" ,
booktitle=    "Proc. of the Int. Conf. on Deductive and
Object-Oriented Databases (DOOD'91)" ,
address    =    "Munich, Germany" ,
month    =    "dec" ,
year    =    "1991" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( JAEGERMANN78,
key    =    "Jaegermann" ,
author    =    "Jaegermann, M." ,
title    =    "Information storage and retrieval systems with
incomplete information" ,
journal    =    "Fundamenta Informatic\ae" ,
volume    =    "II" ,
year    =    "1978" ,
pages    =    "17--41" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( JIA92,
key    =    "Jia et al." ,
author    =    "Jia, Y. and Feng, Z. and Miller, M." ,
title    =    "A Multivalued Approach to Handle Nulls in RDB" ,
booktitle=    "Future Database'92, Proceedings of the Second
Far-East Workshop on Future Database Systems" ,
address    =    "Kyoto, Japan" ,
month    =    "apr" ,
year    =    "1992" ,
pages    =    "71--76" ,
abstract=    " To handle incomplete data in Database and
Information systems is a nontrivial problem. There is no fully
satisfactory design theory incorporating null values in Relational
Database systems. In this paper we present our multivalued logical
proposal to deal with null values in Relational Datanases. This method
is different from classifying nulls into multi categories, such as
Codd's four valued logic which classified nulls into applicable and
inapplica ble nulls, respectively. We believe that four valued logic
cannot cover all possible nulls, and neither can n+1 valued logic. Our
multivalued logical approach is based on traditional three valued
logic, which gives each null value a possible truth degree. The result
of a query will depend on truth degrees of the nulls involved, giving
a 'probabilistic' response to the query. To deal with null values of
various truth degrees we introduce an augmented set of relational and
logical operations. An arithematic operation approach for nulls is
introduced, which we believe can be extended for traditional
relational algebra. To simplify the handling of nulls by a RDBMS, a
measurement of null truth level is proposed. According to the truth
level of a null, RDBMS can decide whether to use it in calculation or
ignore it. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( JICHAO87,
key    =    "Jichao" ,
author    =    "Jichao, H." ,
title    =    "Extending relational model to deal with null value
(in Chinese)" ,
journal    =    "Chinese Journal of Computation" ,
volume    =    "10" ,
number    =    "8" ,
year    =    "1987" ,
pages    =    "449--459" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( JOHNSON91,
key    =    "Johnson" ,
author    =    "Johnson, C. A." ,
title    =    "Handling indefinite and negative data in a
deductive database" ,
journal    =    "Data \& Knowledge Engineering" ,
volume    =    "6" ,
number    =    "4" ,
month    =    "jul" ,
year    =    "1991" ,
pages    =    "333--348" ,
keywords=    "Deductive databases; indefinite data; negative
data; closed world metarules;; Bibel's connection method" ,
abstract=    "We introduce the notion of a minimal
interpretation of an indefinite deductive database and present a
closed world metarule based on this notion with which negative data
may be inferred from the database. We also investigate a possible
implementation of our metarule using a path checking algorithm adapted
from Bibel`s connection method." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( KACPRZYK86,
key    =    "Kacprzyk \& Ziolkowski" ,
author    =    "Kacprzyk, J. and Ziolkowski, A." ,
title    =    "Database queries with fuzzy linguistic quantifiers" ,
journal    =    "IEEE Trans. Syst. Man Cybern. SMC-16" ,
volume    =    "3" ,
month    =    "May/June" ,
year    =    "1989" ,
pages    =    "474--479" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( KACPRZYK89,
key    =    "Kacprzyk et al." ,
author    =    "Kacprzyk, J. and Zadrozny, S. and Ziolkowski, A." ,
title    =    "FQUERY III plus. A 'human-consistent' database
querying system based on fuzzy logic with linguistic quantifiers" ,
journal    =    "Information Sciences" ,
volume    =    "14" ,
number    =    "6" ,
pages    =    "???--???" ,
year    =    "1989" ,
abstract=    " Using a fuzzy-logic-based calculus of
linguistically quantified propositions we present FQUERY III plus , a
new, more 'human-friendly' and easier-to-use implementation of a
querying scheme proposed originally by J. Kacprzyk and A. Ziolkowski
to handle imprecise queries including a linguistic quantifier as, e.g.
'find all records in which most (almost all, much more than 75%,...or
any other linguistic quantifier) of the important attributes (out of a
specified set) are as desired (e.g. equal to five, more than 10,
large, more or less equal to 15, etc.) FQUERY III plus is an 'add-on'
to Ashton- Tate's dBase III Plus. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( KAMEL88,
key    =    "Kamel et al." ,
author    =    "Kamel, M. S. and Loo, W. S. and Wong, A. K. C." ,
title    =    "Intelligent database query translation" ,
booktitle=    "Proceedings of the 1988 IEEE International
Conference on Systems, Man, and Cybernetics" ,
address    =    "Beijing/Shenyang, China" ,
month    =    "aug" ,
year    =    "1988" ,
pages    =    "665--669" ,
abstract=    " The authors discuss techniques for processing
database queries that are not required to be formulated based on
complete and precise knowledge of the query specification as defined
in the database management system. Specific attention is given to
processing queries that are ill-defined, not complete, and fuzzy. The
authors propose a query translator that tries to bridge the gap
between the user's semantically stated query and its full
specification as required by the database. The translator utilizes a
graph-based structure to represent queries and relations in the
database. The translator transforms a logical query graph, modeling a
user's query (which may be ill-defined), into a complete query graph
which provides the detailed description of the query, allowing
corrective responses. An intermediate query language (IQL) has been
developed to serve as input to the translator. The translator has been
implemented using Interlisp-D, and its performance has been
demonstrated. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( KAMEL90,
key    =    "Kamel et al." ,
author    =    "Kamel, M. S. and Hadfield, B. and Ismail, M." ,
title    =    "Fuzzy Query Processing using Clustering Techniques" ,
journal    =    "Information Processing \& Management" ,
volume    =    "26" ,
number    =    "2" ,
year    =    "1990" ,
pages    =    "279--293" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( KAO87,
key    =    "Kao et al." ,
author    =    "Kao, M. and Cercone, N. and Luk, W." ,
title    =    "What do you mean ``Null''? Turning Null Responses
into Quality Responses" ,
booktitle=    "Proceedings of the Third International Conference
on Data Engineering" ,
year    =    "1987" ,
pages    =    "356--364" ,
abstract=    "When natural language {\em front-ends} are
introduced to database management systems, generation of quality
responses have proven problematical in situations when null values
arise. In our work, in which we assume the database query language is
SQL, we present methods for responding with appropriate answers to
null value responses. To do so we use a knowledge base based on RM/T,
an extended relational model proposed by E. F. Codd. The advantages of
this approach are described. To demonstrate the utility of the
knowledge base, a simple knowledge base is constructed. A detailed
algorithm is given to provide additional information when a null
answer is returned." ,
bibdate    =    "Wed Jul 31 09:59:23 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( KELLER84B,
key    =    "Keller \& Wilkins" ,
author    =    "Keller, A. M. and Wilkins, M. W." ,
title    =    "Approaches for Updating Databases With Incomplete
Information and Nulls" ,
booktitle=    "Proceedings of the International Conference on
Data Engineering" ,
organization=    "IEEE Computer Society" ,
publisher=    "IEEE Computer Society Press" ,
address    =    "Los Angeles, CA" ,
month    =    "apr" ,
year    =    "1984" ,
pages    =    "332--340" ,
keywords=    "null values, incomplete information, updates,
databases, relational databases" ,
abstract=    "In this paper we consider approaches to updating
databases containing null values and incomplete information. Our
approach distinguishes between modeling incompletely known worlds and
modeling changes in these worlds. As an alternative to the open and
closed world assumptions, we propose the modified closed world
assumption. Along with the discussion of updating, we address some
issues of refining incompletely specified information." ,
bibdate    =    "Wed Sep  2 14:16:04 1987" ,
owner    =    "mckenzie" ,
)

@article    ( KELLER85C,
key    =    "Keller \& Wilkins" ,
author    =    "Keller, A. M. and Wilkins, M. W." ,
title    =    "On the Use of an Extended Relational Model to
Handle Changing Incomplete Information" ,
journal    =    "tse" ,
publisher=    "IEEE" ,
volume    =    "SE-11" ,
number    =    "7" ,
month    =    "jul" ,
year    =    "1985" ,
pages    =    "620--633" ,
keywords=    "Databases; incomplete information; null values;
relational databases; updates" ,
abstract=    "In this paper we consider approaches to updating
databases containing null values and incomplete information. Our
approach distinguishes between modeling incompletely known worlds and
modeling changes in these worlds. As an alternative to the open and
closed world assumptions, we propose the expanded closed world
assumption. Under this assumption, we discuss how to perform updates
on databases containing set nulls, marked nulls, and simple
conditional tuples, and address some issues of refining incompletely
specified information." ,
bibdate    =    "Tue Jan 20 12:22:53 1987" ,
owner    =    "manning" ,
)

@article    ( KELLER86A,
key    =    "Keller" ,
author    =    "Keller, A. M." ,
title    =    "Set-theoretic Problems of Null Completion in
Relational Databases" ,
journal    =    "Information Processing Letters" ,
volume    =    "22" ,
number    =    "5" ,
month    =    "April" ,
year    =    "1986" ,
pages    =    "261--265" ,
keywords=    "relational databases, null values, set theory,
incomplete information, x-relation" ,
abstract=    "When considering using databases to represent
information, the relationship between two facts where one may imply
the other needs to be addressed. In relational databases, this
question becomes whether null completion is assumed. That is, does a
(possibly partially-defined) tuple imply the existence of tuples that
are ``less informative'' than the original tuple. We show that no
relational algebra, that assumes equivalence under null completion,
can include set-theoretic operators that are compatible with ordinary
set theory. Thus, the approach of x-relations is incompatible with the
axioms of a boolean algebra." ,
bibdate    =    "Wed Aug 19 21:42:40 1987" ,
owner    =    "mckenzie" ,
)

@article    ( KENT91,
key    =    "Kent" ,
author    =    "Kent, W." ,
title    =    "The Breakdown of the Information Model in
Multi-Database Systems" ,
journal    =    "sigmod" ,
volume    =    "20" ,
number    =    "4" ,
year    =    "1991" ,
pages    =    "10--15" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( KENT91A,
key    =    "Kent" ,
author    =    "Kent, W." ,
title    =    "Solving Domain Mismatch and Schema Mismatch
Problems with an Object-Oriented Database Programming Language" ,
booktitle=    "vldb" ,
address    =    "Barcelona, Spain" ,
year    =    "1991" ,
pages    =    "147--160" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( KIESSLING92,
author    =    (Kiessling, W. and Th\"{o}ne, H. and G\"{u}ntzer,
U.) ,
title    =    "Database Support for Problematic Knowledge" ,
year    =    "1992" ,
booktitle=    "Proc. EDBT92 International Conference on Extending
Database Technology" ,
address    =    "Vienna, Austria" ,
)

@inproceedings    ( KIFER88,
key    =    "Kifer \& Li" ,
author    =    "Kifer, M. and Li, A." ,
title    =    "On the Semantics of Rule-Based Expert Systems with
Uncertainty" ,
booktitle=    "Proceedings of the International Conference on
Database Theory" ,
publisher=    "Springer-Verlag" ,
year    =    "1988" ,
pages    =    "102--117" ,
abstract=    "We present a formal semantics for rule-based
systems with uncertainty (this field has also become known as
``quantitative logic programming''). Unlike previous works, our
framework is general enough to accommodate most of the known schemes
of reasoning with uncertainty found in the existing expert systems. We
provide a rigorous treatment of the issue of evidential independence,
and study its impact on the semantics. To the best of our knowledge,
this issue has not been addressed before in the literature on
quantitative logic programming. In expert systems evidential
independence received only an ad hoc treatment, while the approaches
found in the theory of evidential reasoning are feasible only in small
scale systems. We discuss the problem of query optimization and, as a
first-step, present a quantitative semi-naive query evaluation
algorithm -- generalization of a method well-known in deductive
databases. Treatment of negation and conflicting evidence based on, so
called, support logic is given in the last part of the paper, where we
extend the semantics of stratified programs to deal with uncertainty." ,
bibdate    =    "Wed Jul 31 14:17:36 1991" ,
owner    =    "curtis" ,
)

@article    ( KING91,
key    =    "King \& Small" ,
author    =    "King, P. and Small, C." ,
title    =    "Default Databases and Incomplete Information" ,
journal    =    "Computer Journal" ,
volume    =    "34" ,
number    =    "3" ,
month    =    "jun" ,
year    =    "1991" ,
pages    =    "239--244" ,
abstract=    " We present the concept of a default database
which comprises a set of facts, a set of deduction rules, and a set of
defaults. Defaults define assumptions to be made about information not
derivable from the rules and facts. Defaults, by augmenting the
information which is a consequence solely of the rules and facts,
enable definite responses to queries on the basis of 'common sense'
assumptions rather than responses of the form 'unknown'. The augmented
information is termed an extension. Although such an extension is
self- consistent, in general two or more mutually inconsistent
extensions can arise. We characterise the rules and defaults of a
database as safe if only one extension can arise for any given set of
facts. We give conditions which are necessary and sufficient to ensure
safety." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@book        ( KLIR88,
key    =    "Klir \& Folger" ,
author    =    "Klir, G. J. and Folger, T. A." ,
title    =    "Fuzzy Sets, Uncertainty and Information" ,
publisher=    "Prentice-Hall" ,
address    =    "Englewood Cliffs, NJ" ,
year    =    "1988" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( KOCHAREKAR89,
key    =    "Kocharekar" ,
author    =    "Kocharekar, R." ,
title    =    "Nulls in Relational Databases: Revisited" ,
journal    =    "sigmod" ,
volume    =    "18" ,
number    =    "1" ,
month    =    "mar" ,
year    =    "1989" ,
pages    =    "68--73" ,
abstract=    "This paper discusses the semantic issues related
to null values problem in relational databases. We argue that the
proposed set of maybe operations with the three valued logic is still
not adequate and needs further enhancements." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( KORNATZKY93,
key    =    "Kornatzky \& Shimony" ,
author    =    "Kornatzky, Y. and Shimony, S." ,
title    =    "A Probabilistic Spatial Data Model" ,
booktitle=    "DEXA'93" ,
address    =    "Prague, Czech Republic" ,
month    =    "sep" ,
year    =    "1993" ,
abstract=    "Spatial information in autonomous robot tasks is
uncertain due to measurement errors, the dyntamic nature of the world,
and an incompletely known environment. We present a probabilistic
spatial data model capable of describing relevant spatial data, such
as object location, shape, composition, and other parameters, in the
presence of uncertainty. Uncertain spatial information is modeled
through continuous probability distributions on values of attributes.
The data model is designed to support our visual tracking and
navigation prototype." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( KORNATZKY93A,
key    =    "Kornatzky \& Shimony" ,
author    =    "Kornatzky, Y. and Shimony, S." ,
title    =    "A Probabilistic Object-Oriented Data Model" ,
type    =    "TR" ,
number    =    "FC 93-04" ,
institution=    "Ben-Gurion University" ,
year    =    "1993" ,
month    =    "may" ,
abstract=    "Intelligent systems such as autonomous robots
interacting with the real world encounter uncertainty in their
knowledge about the world, due to incomplete information, data
acquisition errors, and uncertainty about cause and effect. To operate
in such an environment, uncertain information needs to be represented
explicitly in their world model (database). We present an
object-oriented data model that describes uncertainty through the use
of probabilities. The model represents uncertainty with respect to
values of attributes, and with respect to class hierarchy." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( KOUBARAKIS93,
key    =    "Koubarakis" ,
author    =    "Koubarakis, M." ,
title    =    "Representation and Querying in Temporal Databases:
the Power of Temporal Constraints" ,
booktitle=    "Proceedings of the International Conference on
Data Engineering" ,
address    =    "Vienna, Austria" ,
month    =    "apr" ,
pages    =    "327--334" ,
year    =    "1993" ,
abstract=    "We propose a temporal database model capable of
representing absolute, relative, imprecise and indefinite temporal
data. Our model is based on temporal tables i.e., relation-like
representations which can contain variables constrained by the
formulas of a temporal theory. We define an algebraic query language
for temporal tables and discuss some problems related to query
answering." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( KOURAMAJIAN92,
key    =    "Kouramajian \& Elmasri" ,
author    =    "Kouramajian, V. and Elmasri, R." ,
title    =    "A Generalized Temporal Model" ,
type    =    "Tech. Report" ,
institution=    "University of Texas at Arlington" ,
year    =    "1992" ,
month    =    "feb" ,
abstract=    " " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( KRATZER85,
key    =    "Kratzer and Schreier" ,
author    =    "Kratzer, K. and Schreier, U" ,
title    =    "Behandlung von Ausnahmesituationen mit einer
Metadatenbank" ,
booktitle=    (Proc. GI-Fachtagung, Datenbank-Systeme f\"ur
B\"uro, Technik und Wissenschaft, Germany) ,
address    =    "Karlsruhe, Germany" ,
year    =    "1985" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( KURUTACH93,
key    =    "Kurutach \& Franklin" ,
author    =    "Kurutach, W. and Franklin, J." ,
title    =    "On Temporal-fuzziness in Temporal Fuzzy Databases" ,
booktitle=    "DEXA'93" ,
address    =    "Prague, Czech Republic" ,
month    =    "sep" ,
year    =    "1993" ,
pages    =    "154--165" ,
abstract=    "We propose a framework for a database model
unifying both imprecision and time aspects of data. Particularly, we
emphasize that the fuzzy meanings of linguistic data can change with
time; we call this property temporal-fuzziness. The major problems
arising from the lack of the ability to handle this property have been
studied, i.e. users and databases misinterpret the meaning of data.
Thus, it is essential to treat temporal-fuzziness within an
appropriate framework like ours. In our work, we employ concepts based
on fuzzy set theory - possibility theory and linguistic variables -
for modeling and evaluating uncertain/imprecise data from three domain
types, i.e.. quantitative, qualitative, and multivalued logic data
domains. To model past data, the tuple time stamping method and the
discrete time conceptual model are utilized. We introduce three kinds
of measures for each domain type to evaluate data. They can provide
upper bounded, lower bounded, and approximate answers to queries.
Then, Temporal Fuzzy Data Model and a metadatabase are proposed. The
condept of metadatabase allows the time-variant property of fyzzy
meanings to be modeled. Since based on the relational model, our model
has a uniform and simple structure." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( LACROIX76,
key    =    "Lacroix \& Pirotte" ,
author    =    "Lacroix, M. and Pirotte, A." ,
title    =    "Generalized Joins" ,
journal    =    "sigmod" ,
volume    =    "8" ,
number    =    "3" ,
year    =    "1976" ,
pages    =    "14--15" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( LAKSHMANAN88,
key    =    "Lakshmanan" ,
author    =    "Lakshmanan, V. S." ,
title    =    "Query Evaluation with Null Values: Completeness
and Complexity" ,
year    =    "1988" ,
pages    =    "218--227" ,
booktitle=    "Office and Data Base Systems Research" ,
address    =    "Computer Systems Research Institute, University of
Toronto, Toronto, Canada, M5S 1A1" ,
month    =    "sep" ,
)

@inproceedings    ( LAKSHMANAN89,
key    =    "Lakshmanan" ,
author    =    "Lakshmanan, V. S." ,
title    =    "Query Evaluation with Null Values: How Complex is
Completeness?" ,
booktitle=    "Proceeding of the Ninth Conference on Foundations
of Software Technology and Theoretical Computer Science" ,
address    =    "Bangalore, India" ,
month    =    "dec" ,
year    =    "1989" ,
pages    =    "204--222" ,
abstract=    "do not have article " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( LAURENT88,
key    =    "Laurent \& Spyratos" ,
author    =    "Laurent, D. and Spyratos, N." ,
title    =    "Partition Semantics for Incomplete Information in
Relational Databases" ,
booktitle=    "sigmod" ,
organization=    "acm" ,
publisher=    "ACM Press" ,
year    =    "1988" ,
pages    =    "66--73" ,
abstract=    "We define partition semantics for databases with
incomplete information and we present an algorithm for query
processing in the presence of incomplete information and functional
dependencies. We show that Lipski's model for databases with
incomplete information can be seen as a special case of our model." ,
bibdate    =    "Wed Jul 31 14:17:36 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( LEE92,
key    =    "Lee" ,
author    =    "Lee, S. K." ,
title    =    " An Extended Relational Database Model for
Uncertain and Imprecise Information" ,
booktitle=    "vldb" ,
address    =    "Vancouver, Canada" ,
month    =    "aug" ,
year    =    "1992" ,
bibdate    =    "Wed Apr  1 15:20:41 1992" ,
owner    =    "curtis" ,
)

@inproceedings    ( LEE92B,
key    =    "Lee" ,
author    =    "Lee, S. K." ,
title    =    "Imprecise and Uncertain Information in Databases:
An Evidential Approach" ,
booktitle=    "Proceedings of the International Conference on
Data Engineering" ,
organization=    "ieee" ,
publisher=    "IEEE Computer Society Press" ,
address    =    "Los Alamitos, CA" ,
editor    =    "Golshani, F." ,
volume    =    "8" ,
month    =    "feb" ,
year    =    "1992" ,
pages    =    "614--621" ,
abstract=    "A new approach of representing imprecise and
uncertain data and evaluating queries in the framework of an extended
relational database model based on the Dempster-Shafer theory of
evidence is proposed. Because of the ability of combining evidences
from different sources, the semantics of the update operation of
imprecise or uncertain data is reconsidered. By including an undefined
value in a domain, three different cases of a null value is presented:
unknown, inapplicable, and unknown or inapplicable. In this model, two
levels of uncertainty in the database are supported: one is for the
attribute value level, the other is for the tuple level." ,
bibdate    =    "Fri Sep  4 22:01:47 1992" ,
owner    =    "leoso" ,
)

@inproceedings    ( LEFONS83,
key    =    "Lefons et al." ,
author    =    "Lefons, E. and Silvestri, A. and Tangorra, F." ,
title    =    "An Analystic Approach to Statistical Databases" ,
booktitle=    "vldb" ,
address    =    "Florence, Italy" ,
month    =    "oct" ,
year    =    "1983" ,
pages    =    "260--274" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( LEIKAUF89,
key    =    "Leikauf" ,
author    =    "Leikauf, P." ,
title    =    "Konsistenzsicherung durch Verwaltung von
Konsistenzverletzungen" ,
booktitle=    (Proc. GI-Fachtagung, Datenbank-Systeme f\"ur
B\"uro, Technik und Wissenschaft, Germany) ,
address    =    (Z\"urich, Switzerland) ,
year    =    "1989" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( LENZERINI91,
key    =    "Lenzerini" ,
author    =    "Lenzerini, M." ,
title    =    "Type Data Bases with Incomplete Information" ,
journal    =    "Information Sciences" ,
volume    =    "53" ,
year    =    "1991" ,
pages    =    "61--87" ,
abstract=    "The type data base is the part of the data base in
which all the information about classes, membership relationships
between objects and classes, and interdependencies among classes are
collected. We study specific type data bases, which allow for
representing different kinds of incomplete information, such as
existential and disjunctive assertions. In particular, we address the
problems of consistency checking and query answering, proposing
efficient solutions for both of them. Our analysis is carried out in
the context of the logical approach to data bases and knowledge
representation, which provides a suitable formal basis for the
treatment of incomplete information." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( LERAT86A,
key    =    "Lerat" ,
author    =    "Lerat, N." ,
title    =    "Query Processing in Incomplete Logical Databases" ,
booktitle=    "Proceedings of the International Conference on
Database Theory" ,
publisher=    "Springer-Verlag" ,
address    =    "Rome, Italy" ,
editor    =    "Ausiello, G. and Atzeni, P." ,
month    =    "sep" ,
year    =    "1986" ,
pages    =    "260--277" ,
abstract=    "An incomplete database $T$ combines two types of
information about the real world modeled by the database: (a) the
relational database with null values (``value not known'') represented
by axioms of First Order Theory $T_0$ and (b) the data dependencies
that are known to be satisfied in the real world. For a given set of
dependencies (functional and inclusion dependencies), a chase process
transforms in two steps (``forward'' and ``backward'' chase) type (b)
information into an equivalent type (a) form. This yields a new first
order theory $T_1$; for a class $\Gamma$ of queries (subclass of
monotone queries) the evaluation on $T$ and on $T_1$ are equivalent. A
technique involving both algebraic and theorem-proving methods
provides for a sound and complete evaluation of the query." ,
bibdate    =    "Wed Jul 31 14:17:36 1991" ,
owner    =    "curtis" ,
)

@article    ( LERAT86B,
key    =    "Lerat \& Lipski" ,
author    =    "Lerat, N. and Lipski, W., Jr." ,
title    =    "Nonapplicable Nulls" ,
journal    =    "Theoretical Computer Science" ,
publisher=    "North-Holland" ,
volume    =    "46" ,
year    =    "1986" ,
pages    =    "67--82" ,
abstract=    "A nonapplicable null appears in a relation
whenever the value of the corresponding attribute does not exist. In
order to evaluate a query on a relation {\em r} involving such null
values, the information contained in {\em r} is represented by a set
of {\em null-free} instances, then the query on {\em r}--expressed in
a {\em user-friendly} query language ({\em Generalized Relational
Calculus})--is translated into a set of queries on the null-free
instances. Conversely, we define the operations on relations with
nulls ({\em Generalized Relational Algebra}) and we proved an
extension of Codd's completeness theorem." ,
bibdate    =    "Wed Jul 31 14:17:36 1991" ,
owner    =    "curtis" ,
)

@article    ( LEVENE91,
key    =    "Levene \& Loizou" ,
author    =    "Levene, M. and Loizou, G." ,
title    =    "Correction to Null Values in Nested Relational
Databases by M. A. Roth, H. F. Korth, and A. Silberschatz" ,
journal    =    "Acta Informatica" ,
volume    =    "28" ,
year    =    "1991" ,
pages    =    "603--605" ,
abstract=    "We show that the extended projection of a nested
relation in Partitioned Normal Form (PNF) is not a precise
generalization of standard projection with respect to unnesting and
PNF possibility function POSS*." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@book        ( LEVENE92,
key    =    "Levene" ,
author    =    "Levene, M." ,
title    =    "The Nested Universal Relation Database Model" ,
year    =    "1992" ,
publisher=    "Springer-Verlag" ,
series    =    "Lecture Notes in Computer Science 595" ,
)

@inproceedings    ( LEVESQUE80,
key    =    "Levesque" ,
author    =    "Levesque, H. J." ,
title    =    "Incompleteness in Knowledge Bases" ,
booktitle=    "Proc. of the Workshop on Data Abstraction,
Databases and Conceptual Modeling" ,
address    =    "Pingree Park, CO" ,
month    =    "jun" ,
year    =    "1980" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( LEVESQUE81,
key    =    "Levesque" ,
author    =    "Levesque, H. J." ,
title    =    "The interaction with incomplete knowledge bases: a
formal treatment" ,
booktitle=    "ijcai" ,
address    =    "Vancouver, B.C." ,
month    =    "aug" ,
year    =    "1981" ,
pages    =    "240--245" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@phdthesis    ( LEVESQUE82A,
key    =    "Levesque" ,
author    =    "Levesque, H. J." ,
title    =    "A Formal Treatment of Incomplete Knowledge Bases" ,
school    =    "University of Toronto" ,
address    =    "Toronto, Canada" ,
month    =    "feb" ,
year    =    "1982" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( LEVESQUE82B,
key    =    "Levesque" ,
author    =    "Levesque, H. J." ,
title    =    "A Formal Treatment of Incomplete Knowledge Bases" ,
type    =    "FLAIR Technical Report" ,
number    =    "3" ,
institution=    "Fairchild Laboratory for Artificial Intelligence
Research, Palo Alto, CA" ,
year    =    "1982" ,
month    =    "feb" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@incollection    ( LEVESQUE84,
key    =    "Levesque" ,
author    =    "Levesque, H. J." ,
title    =    "The Logic of Incomplete Databases" ,
booktitle=    "On Conceptual Modeling: Perspectives from
Artificial Intelligence Databases and Programming Languages" ,
editor    =    "M. Brodie, J. Mylopoulos, and J.W. Schmidt" ,
publisher=    "Springer-Verlag" ,
address    =    "Berlin and New York" ,
year    =    "1984" ,
pages    =    "165--186" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( LIEN79,
key    =    "Lien" ,
author    =    "Lien, Y." ,
title    =    "Multivalued Dependencies with Null Values in
Relational Data Bases" ,
booktitle=    "vldb" ,
year    =    "1979" ,
pages    =    "61--66" ,
abstract=    "The role of null values in a relational data base
is considered within the framework of multivalued dependencies. When a
relation contains null values, a different treatment of data
dependencies and different relational operations such as projection
and join, are necessary, This paper develops a complete axiomatization
for the revised multivalued dependencies. In particular,
complementation, reflexivity, augmentation, and union are shown to be
a complete set of inference rules. In contrast with the conventional
multivalued dependencies, the transitivity rule cannot be used. These
results provide a framework for the use of the revised multivalued
dependencies in choosing relations and their attributes for a feasible
data-base design." ,
bibdate    =    "Wed Jul 31 14:17:36 1991" ,
owner    =    "curtis" ,
)

@article    ( LINN87,
key    =    "Linn" ,
author    =    "Linn, F." ,
title    =    "Missing and Inapplicable Values" ,
journal    =    "sigmod" ,
publisher=    "acm" ,
volume    =    "16" ,
number    =    "2" ,
month    =    "sep" ,
year    =    "1987" ,
pages    =    "18--19" ,
abstract=    "None given." ,
bibdate    =    "Wed Jul 31 17:58:23 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( LIPSKI76,
key    =    "Lipski" ,
author    =    "Lipski, W., Jr." ,
title    =    "Informational Systems with Incomplete Information" ,
booktitle=    "Proceedings of the 3rd International Colloquium on
Automata, Languages and Programming" ,
address    =    "Edinburgh, Scotland" ,
month    =    "jul" ,
year    =    "1976" ,
pages    =    "120--130" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( LIPSKI77,
key    =    "Lipski" ,
author    =    "Lipski, W., Jr." ,
title    =    "On the logic of incomplete information" ,
booktitle=    "Proceedings of the 6th International Symposium on
the Mathematical Foundations of Computer Science" ,
address    =    "Tatransk\'{a} Lomnica, Czechoslovakia" ,
month    =    "sep" ,
year    =    "1977" ,
pages    =    "374--381" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( LIPSKI77A,
key    =    "Lipski" ,
author    =    "Lipski, W., Jr." ,
title    =    "On Semantic Issues Connected with Incomplete Data
Bases (extended abstract)" ,
booktitle=    "vldb" ,
month    =    "oct" ,
address    =    "Florence, Italy" ,
year    =    "1977" ,
pages    =    "491" ,
abstract=    "do not have article QA 76.9 area" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( LIPSKI79B,
key    =    "Lipski" ,
author    =    "Lipski, W., Jr." ,
title    =    "On Semantic Issues Connected with Incomplete
Information Databases" ,
journal    =    "tods" ,
publisher=    "ACM" ,
volume    =    "4" ,
number    =    "3" ,
month    =    "sep" ,
year    =    "1979" ,
pages    =    "262--296" ,
bibdate    =    "Sun Nov  6 10:30:39 1988" ,
owner    =    "" ,
abstract=    "Various approaches to interpreting queries in a
database with incomplete information are discussed. A simple model of
a database is described, based on attributes which can take values in
specific attribute domains. Information incompleteness means that
instead of having a single value of an attribute, we have a subset of
the attribute domain, which represents our knowledge that the actual
value, though unknown, is one of the values in this subset. This
extends the idea of Codd's null value corresponding to the case when
this subset is the whole attribute domain. A simple query language to
communicate with such a system is described and its various semantics
are precisely defined. We emphasize the distinction between two
different interpretations of the query language -- the external one,
which refers the queries directly to the real world modeled in an
incomplete way by the system, and the internal one, under which the
queries refer to the system's information about this world rather than
to the world itself. Both external and internal interpretations are
provided with the corresponding sets of axioms which serve as a basis
for equivalent transformations of queries. The technique of equivalent
transformations of queries is then extensively exploited for
evaluating the interpretation of (i.e. the response to) a query" ,
)

@article    ( LIPSKI81,
key    =    "Lipski" ,
author    =    "Lipski, W., Jr." ,
title    =    "On Databases with Incomplete Information" ,
journal    =    "jacm" ,
volume    =    "28" ,
number    =    "1" ,
year    =    "1981" ,
pages    =    "41--70" ,
keywords=    "database, incomplete information, query language
semantics, implicit information, modal logic, relational model, null
values" ,
abstract=    "Semantic and logical problems arising in an
incomplete information database are investigated. A simple query
language is described, and its semantics, which refers the queries to
the information about reality contained in a database, rather than to
reality itself, is defined. This approach, called the internal
interpretation, is shown to lead in a natural way to the notions of a
topological Boolean algebra and a model logic related to S4 in the
same way as referring queries directly to reality (external
interpretation) leads to Boolean algebras and classical logic. An
axiom system is given for equivalent (with respect to the internal
interpretation) transformation of queries, which is then exploited as
a basic tool in a method for computing the internal interpretation for
a broad class of queries. An interesting special case of the problem
of determining the internal interpretation amounts to deciding whether
an assertion about reality (a ``yes-no'' query) is consistent with the
incomplete information about reality contained in a database. A
solution to this problem, which relies on the classical combinatorial
problem of distinct representatives of subset, is given." ,
bibdate    =    "Mon Apr  1 15:18:35 1991" ,
owner    =    "curtis" ,
)

@techreport    ( LIPSKI83,
key    =    "Lipski" ,
author    =    "Lipski, W., Jr." ,
title    =    "Logical Problems Related to Incomplete Information
in Databases" ,
type    =    "Technical Report" ,
number    =    "138" ,
institution=    "Laboratoire de Recherche en Informatique,
Universit\'{e} de Paris-Sud, Centre d'Orsay" ,
year    =    "1983" ,
month    =    "sep" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( LIPSKI84,
key    =    "Lipski" ,
author    =    "Lipski, W., Jr." ,
title    =    "On Relational Algebra with Marked Nulls" ,
booktitle=    "pods" ,
address    =    "Waterloo, Ontario, Canada" ,
month    =    "apr" ,
year    =    "1984" ,
pages    =    "201--203" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( LIU87,
key    =    "Liu \& Sunderraman" ,
author    =    "Liu, K. C. and Sunderraman, R." ,
title    =    "Applying an Extended Relational Model to
Indefinite Deductive Databases" ,
booktitle=    "Proceedings of the 2nd International Symposium on
Methodologies for Intelligent Systems" ,
address    =    "Charlotte, NC" ,
month    =    "oct" ,
year    =    "1987" ,
pages    =    "175--184" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( LIU88,
key    =    "Liu \& Sunderraman" ,
author    =    "Liu, K. C. and Sunderraman, R." ,
title    =    "On representing indefinite and maybe information
in relational databases" ,
booktitle=    "International Conference on Data Engineering" ,
address    =    "Los Angeles, CA" ,
month    =    "feb" ,
year    =    "1988" ,
pages    =    "250--257" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( LIU90A,
key    =    "Liu \& Sunderraman" ,
author    =    "Liu, K. C. and Sunderraman, R." ,
title    =    "Indefinite and Maybe Information in Relational
Databases" ,
journal    =    "tods" ,
volume    =    "15" ,
number    =    "1" ,
month    =    "mar" ,
year    =    "1990" ,
pages    =    "1--39" ,
keywords=    "first-order logic; incomplete information;
indefinite databases; indefinite/disjunctive information; maybe
information; query; relational algebra; relational database" ,
abstract=    "This paper extends the relational model to
represent indefinite and maybe kinds of incomplete information. A data
structure, called I-table, which is capable of representing indefinite
and maybe facts is introduced. The information content of I-tables is
precisely defined, and an operator to remove redundant facts is
presented. The relational algebra is then extended in a semantically
correct way to operate on I-tables. Queries are posed in the same way
as in conventional relational algebra; however, the user may now
expect indefinite as well as maybe answers." ,
bibdate    =    "Tue Apr 10 13:33:56 1990" ,
owner    =    "robyn" ,
)

@inproceedings    ( LIU90B,
key    =    "Liu \& Sunderraman" ,
author    =    "Liu, K. C. and Sunderraman, R." ,
title    =    "On Representing Indefinite and Maybe Information
in Relational Databases: a Generalization" ,
booktitle=    "Proceedings of the Sixth International Conference
on Data Engineering" ,
year    =    "1990" ,
pages    =    "495--502" ,
abstract=    "This paper generalizes the relational model to
rep- resent indefinite and maybe kinds of incomplete information. A
data structure, called {\em M-table}, is introduced which is capable
of representing disjunctive/indefinite and maybe facts. The notion of
redundancy in the context of indefinite and maybe information is
studied. The information content of an M-table is precisely defined.
The relational algebra is then generalized in a semantically correct
manner to operate on M-tables. Queries are posed in the same manner as
in the conventional relational algebra, however the user may now
expect indefinite as well as maybe answers." ,
bibdate    =    "Wed Jul 31 09:59:23 1991" ,
owner    =    "curtis" ,
)

@article    ( LIU91A,
key    =    "Liu \& Sunderraman" ,
author    =    "Liu, K. C. and Sunderraman, R." ,
title    =    "A Generalized Relational Model for Indefinite and
Maybe Information" ,
journal    =    "tkde" ,
volume    =    "3" ,
number    =    "1" ,
year    =    "1991" ,
pages    =    "65--76" ,
keywords=    "database, incomplete information, indefinite
database, maybe information, query, relational algebra, relational
model" ,
abstract=    "This paper generalizes the relational model to
represent indefinite and maybe kinds of incomplete information. A data
structure, called {\em M-table}, is introduced which is capable of
representing disjunctive/indefinite and maybe facts. The notion of
redundancy in the context of indefinite and maybe information is
studied. The information content of an {\em M-table} is precisely
defined. The relational algebra is then generalized in a semantically
correct manner to operate on {\em M-tables}. Two additional operators
{\em R-projection} and {\em merge}, are introduced. Queries are posed
in the same manner as in the conventional relational algebra, however
the user may now expect indefinite as well as maybe answers." ,
bibdate    =    "Sun Apr  7 17:11:20 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( LIU91B,
key    =    "Liu \& Sunderraman" ,
author    =    "Liu, K. C. and Sunderraman, R." ,
title    =    "Natural Joins in Relational Databases with
Indefinite and Maybe Information" ,
booktitle=    "Proceedings of the Seventh International
Conference on Data Engineering" ,
year    =    "1991" ,
pages    =    "132--194" ,
abstract=    "Natural joins are defined, in a semantically
correct way, on I-tables of an extended relational database model with
indefinite and maybe information. Rudimentary or naive algorithms for
computing natural joins on I-tables require an exponential number of
pair-up operations and block access proportional to the size of
I-tables. This is due to the combinatorial nature of natural joins on
I-tables. Thus, the problem becomes intractable for large I-tables. In
this paper, we propose an algorithm for computing natural joins under
the extended model which reduces the number of pair-up operations and
block accesses to a linear order of complexity with respect to the
size of I-tables." ,
bibdate    =    "Wed Jul 31 09:59:23 1991" ,
owner    =    "curtis" ,
)

@article    ( LOPEZPERMOUTH90,
key    =    "Lopez-Permouth" ,
author    =    "Lopez-Permouth, S. R." ,
title    =    "On Categories of Fuzzy Models" ,
journal    =    "Information Services" ,
volume    =    "53" ,
year    =    "1990" ,
pages    =    "211--220" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( LOZINSKII88,
key    =    "Lozinskii" ,
author    =    "Lozinskii, E." ,
title    =    "Computing Facts in Non-{H}orn Deductive Systems" ,
year    =    "1988" ,
pages    =    "273--279" ,
booktitle=    "vldb" ,
month    =    "aug" ,
)

@inproceedings    ( LOZINSKII89,
key    =    "Lozinskii" ,
author    =    "Lozinskii, E." ,
title    =    "Plausible World Assumption" ,
year    =    "1989" ,
pages    =    "266--275" ,
booktitle=    "Proceedings of the First International Conference
on Principles of Knowledge Representation and Reasoning" ,
month    =    "may" ,
)

@article    ( LOZINSKII89A,
key    =    "Lozinskii" ,
author    =    "Lozinskii, E. L." ,
title    =    "Answering atomic queries in indefinite deductive
databases" ,
journal    =    "International Journal of Intelligent Systems" ,
volume    =    "4" ,
number    =    "4" ,
month    =    "Winter" ,
year    =    "1989" ,
pages    =    "403--429" ,
abstract=    " Answering queries in indefinite systems is a
difficult problem both computationally, since it involves non-Horn
clauses and factoring, and conceptually, concerning producting beliefs
for formulas not derivable from the system. To provide a basis for
reasonable beliefs, we propose new criteria as an alternative to the
Full Information Principle. Then an approach to producing stable
beliefs, called Plausible World Assumption (PWA), is introduced. It is
shown how a set of non-Horn clauses can be transformed into a set of
so called singleton-head-rules such that evaluation of a given query
is reduced to processing of a set of Horn clauses relevant to the
query. Finally, algorithms are presented for computing facts and
beliefs for atomic queries in accord with the PWA. This method is
shown to be more efficient than the known techniques for query
evaluation in indefinite systems. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inbook        ( MAIER83A,
key    =    "Maier" ,
author    =    "Maier, D." ,
title    =    "Null Values, Partial Information, and Database
Semantics" ,
booktitle=    "The Theory of Relational Databases" ,
publisher=    "Computer Science Press" ,
address    =    "Rockville, MD" ,
year    =    "1983" ,
chapter    =    "12" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( MANSFIELD92,
key    =    "Mansfield \& Fleischman" ,
author    =    "Mansfield, W. H. and Fleischman, R. M." ,
title    =    "A High Performance, Ad-Hoc, Fuzzy Query Processing
System for Relational Databases" ,
booktitle=    "Proceedings of the North American Fuzzy
Information Processing Society" ,
month    =    "dec" ,
year    =    "1992" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( MATYUTA89,
key    =    "Matyuta et al." ,
author    =    "Matyuta, T. A. and Pasichnik, V. V. and Stogniy,
A. A." ,
title    =    "Means for Management of Relational Fuzzy Databases
- Way to Merging of Systems of Data Bases and Knowledge Bases" ,
year    =    "1989" ,
pages    =    "337--346" ,
booktitle=    "Proc. First Symposium on Mathematical Fundamentals
of Database Systems" ,
address    =    "Visegrad, Hungary" ,
month    =    "jun" ,
)

@article    ( MENDELSON86,
key    =    "Mendelson \& Saharia" ,
author    =    "Mendelson, H. and Saharia, A." ,
title    =    "Incomplete Information Costs and Database Design" ,
journal    =    "tods" ,
volume    =    "11" ,
number    =    "2" ,
year    =    "1986" ,
pages    =    "159--185" ,
abstract=    "This paper presents a methodology for trading-off
the cost of incomplete information against the data-related costs in
the design of database systems. It investigates how the usage patterns
of the database, defined by the characteristics of information
requests presented to it, affect its conceptual design. The
construction of minimum-cost answers to information requests for a
variety of query types and cost structures is also studied. The
resulting costs of incomplete database information are balanced
against the data-related costs in the derivation of the optimal
design." ,
bibdate    =    "Mon Apr  1 15:18:35 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( MEYDEN90,
key    =    "van der Meyden" ,
author    =    "van der Meyden, R." ,
title    =    "Recursively Indefinite Databases (Extended
Abstract)" ,
booktitle=    "International Conference on Database Theory" ,
year    =    "1990" ,
pages    =    "364--378" ,
abstract=    "We define recursively indefinite databases, a new
type of logical database in which indefinite information arises from
partial knowledge of the fixpoint of a datalog program. Although, in
general, query answering is undecidable, there exists a broad class of
queries for which it is decidable, a result we establish by making
connections with the theory of hypergraph edge replacement graph
grammars. We analyze the complexity of query answering for this class
of queries under various constraints and demonstrate a class of
databases which generalizes disjunctive databases, but without
increasing data complexity." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( MICHALEWICZ87,
key    =    "Michalewicz \& Yeo" ,
author    =    "Michalewicz, Z. and Yeo, A." ,
title    =    "Sets in Relational Databases" ,
year    =    "1987" ,
pages    =    "237--245" ,
booktitle=    "Proc. of the Canadian Information Processing
Society" ,
address    =    "Edmonton, Canada" ,
month    =    "nov" ,
)

@inproceedings    ( MICHALEWICZ88,
key    =    "Michalewicz \& Groves" ,
author    =    "Michalewicz, Z. and Groves, L. J." ,
title    =    "Sets and Uncertainty in Relational Databases" ,
year    =    "1988" ,
pages    =    "127--137" ,
booktitle=    "Uncertainty and Intelligent Systems, IPMU'88" ,
address    =    "Urbino, Italy" ,
month    =    "jul" ,
)

@incollection    ( MICHALEWICZ88A,
key    =    "Michalewicz \& Groves" ,
author    =    "Michalewicz, Z. and Groves, L. J." ,
title    =    "Sets and uncertainty in relational databases" ,
booktitle=    "Uncertainty and Intelligent Systems" ,
editor    =    "Bouchon, B. and Saitta, L and Yager, R. R." ,
publisher=    "Springer Verlag" ,
address    =    "Berlin-New York" ,
year    =    "1988" ,
pages    =    "127--137" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( MICHALEWICZ89,
key    =    "Michalewicz \& Chen" ,
author    =    "Michalewicz, Z. and Chen, K." ,
title    =    "Uncertain information in relational databases" ,
journal    =    "International Journal of Policy and Information
(Taiwan)" ,
volume    =    "13" ,
number    =    "2" ,
month    =    "dec" ,
year    =    "1989" ,
pages    =    "187--202" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( MILLER89A,
key    =    "Miller \& Hurson" ,
author    =    "Miller, L. L. and Hurson, A. R." ,
title    =    "Interpretation of null values in database machine
architecture" ,
journal    =    "Microprocessing and Microprogramming" ,
volume    =    "26" ,
number    =    "4" ,
month    =    "dec" ,
year    =    "1989" ,
pages    =    "289--300" ,
abstract=    " Missing or incomplete data continue to be a
common problem in the data processing environment. Hardware solutions
to the database problem, namely the database machines must be able to
provide an adequate solution to handling missing data in order to
compete with current software solutions. We examine the optimal level
of interpreting missing data values in the database machine - the
Associative Search Language Machine (ASLM). Two approaches are
identified and an analytical evaluation of the two methods is given. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inbook        ( MINKER82,
key    =    "Minker" ,
author    =    "Minker, J." ,
title    =    "On Indefinite Databases and the Closed World
Assumption" ,
booktitle=    "6th Conference on Automated Deduction" ,
publisher=    "Springer-Verlag" ,
year    =    "1982" ,
series    =    "Lecture Notes in Computer Science" ,
volume    =    "138" ,
pages    =    "292--308" ,
abstract=    "A database is said to be indefinite if there is an
answer to a query of the form $P(a) \Or P(b)$ where neither $P(a)$ nor
$P(b)$ can be derived from the database. Indefinite databases arise
where, in general, the data consists of non-Horn clauses. A clause is
non-Horn if it is a disjunction of literals in which more than one
literal in the clause is positive. Horn databases, which comprise most
databases in existence, do not admit answers of the form $P(a) \Or
P(b)$ where neither $P(a)$ nor $P(b)$ are derivable from the database.
It has been shown by Reiter that in such databases one can make an
assumption, termed the Closed World Assumption (CWA), that to prove
that $\not P(a)$ is true, one can try to prove $P(a)$, and if the
proof for $P(a)$ fails, one can assume $\not P(a)$ is true. When a
database consists of Horn and non-Horn clauses, Reiter has shown that
it is not possible to make the CWA. In this paper we investigate
databases that consist of Horn and non-Horn clauses. We extend the
definition of CWA to apply to such databases. The assumption needed
for such databases is termed the Generalized Closed World Assumption
(GCWA). Syntactic and semantic definitions of generalized closed
worlds are given. It is shown that the two definitions are equivalent.
In addition, given a class of null values it is shown that the GCWA
gives a correct interpretation for null values." ,
bibdate    =    "Mon Apr  1 15:18:35 1991" ,
owner    =    "curtis" ,
)

@techreport    ( MINKER83,
key    =    "Minker" ,
author    =    "Minker, J." ,
title    =    "On theories of definite and indefinite databases" ,
type    =    "TR" ,
number    =    "1250" ,
institution=    "Department of Computer Science, University of
Maryland" ,
year    =    "1983" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( MONTGOMERY81,
key    =    "Montgomery \& Ruspini" ,
author    =    "Montgomery, C. A. and Ruspini, E. H." ,
title    =    "The Active Information System: A Data-Driven
System for the Analysis of Imprecise Data" ,
booktitle=    "vldb" ,
publisher=    "IEEE Computer Press" ,
year    =    "1981" ,
pages    =    "376--384" ,
abstract=    "The concept of Active Information System is
introduced. Active Information Systems are collections of autonomous,
data-driven tools operating in a data base environment and seeking to
produce results that enhance the understandability of the contents of
the data base. The activities of the corresponding multiple concurrent
processes are coordinated by control mechanisms that perform in a goal
oriented manner. The data models supported by Active Systems are
characterized by the existence of numerous data elements that are
known only in imprecise or uncertain terms. The different types of
components of Active Systems are identified and their organization
into a prototypical architecture is described. Emphasis is placed on
algorithms that assist users in hypothesis generation and verification
tasks. These algorithms are based on concepts from data base
technology, knowledge based systems, system science and multivalued
logic. The technological approaches utilized in the development of an
Active System testbed to treat problems of natural language
understanding and uncertainty representation are discussed in detail." ,
bibdate    =    "Mon Jul 22 14:20:59 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( MORRISSEY87,
key    =    "Morrissey \& van Rijsbergen" ,
author    =    "Morrissey, J. M. and van Rijsbergen, C." ,
title    =    "A Formal Treatment of Missing \& Imprecise
Information" ,
booktitle=    "Proceedings of the Tenth Annual ACM SIGIR
Conference on Research and Development in Information Retrieval" ,
year    =    "1987" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( MORRISSEY90,
key    =    "Morrissey" ,
author    =    "Morrissey, J. M." ,
title    =    "Imprecise Information and Uncertainty in
Information Systems" ,
journal    =    "ACM Transactions on Office Information Systems" ,
volume    =    "8" ,
number    =    "2" ,
month    =    "apr" ,
year    =    "1990" ,
pages    =    "159--180" ,
abstract=    "Information systems exist to model, store, and
retrieve all types of data. Problems arise when some of the data are
missing or imprecisely known or when an attribute is not applicable to
a particular object. A consistent and useful treatment of such
exceptions is necessary. The approach taken here is to allow any
attribute value to be a regular precise value, a string denoting that
the value is missing, a string denoting that the attribute is not
applicable, or an imprecise value. The imprecise values introduce
uncertainty into query evaluation, since it is no longer obvious which
objects should be retrieved. To handle the uncertainty, two set of
objects are retrieved in response to every query: the set of objects
that are known to satisfy with complete certainty and the set that
possibly satisfies the query with various degrees of uncertainty. Two
methods of estimating this uncertainty, based on information theory,
are proposed. The measure of uncertainty is used to rank objects for
presentation to a user." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( MOTRO88A,
key    =    "Motro" ,
author    =    "Motro, A." ,
title    =    "VAGUE: a user interface to relational databases
that permits vague queries" ,
journal    =    "ACM Transactions on Office Information Systems" ,
volume    =    "6" ,
number    =    "3" ,
month    =    "jul" ,
year    =    "1988" ,
pages    =    "187--214" ,
abstract=    " A specific query establishes a rigid
qualification and is concerned only with data that match it precisely.
A vague query establishes a target qualification and is concerned also
with data that are close to this target. This article describes a
system called VAGUE that can handle vague queries directly. The
principal concept behind VAGUE is its extension to the relational data
model with data metrics, which are definitions of distances between
values of the same domain. A problem with implementing data distances
is that different users may have different interpretations for the
notion of distance. VAGUE incorporates several features that enable it
to adapt itself to the individual views and priorities of its users. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( MOTRO89,
key    =    "Motro" ,
author    =    "Motro, A." ,
title    =    "Integrity = Validity + Completeness" ,
journal    =    "tods" ,
volume    =    "14" ,
number    =    "4" ,
month    =    "dec" ,
year    =    "1989" ,
pages    =    "480--502" ,
keywords=    "closed world assumption; completeness; integrity;
integrity constraints; metarelation; relational algebra; relational
database; relational view; validity" ,
abstract=    "Database integrity has two complementary
components: validity, which guarantees that all false information is
excluded from the database, and completeness, which guarantees that
all true information is included in the database. This article
describes a uniform model of integrity for relational databases, that
considers both validity and completeness. To a large degree, this
model subsumes the prevailing model of integrity (i.e., integrity
constraints). One of the features of the new model is the
determination of the integrity of answers issued by the database
system in response to user queries. To users, answers that are
accompanied with such detailed certifications of their integrity are
more meaningful. First, the model is defined and discussed. Then, a
specific mechanism is described that implements this model. With this
mechanism, the determination of the integrity of an answer is a
process analogous to the determination of the answer itself." ,
bibdate    =    "Thu Feb  1 14:33:51 1990" ,
owner    =    "robyn" ,
)

@article    ( MOTRO89A,
key    =    "Motro" ,
author    =    "Motro, A." ,
title    =    "A Trio of Database User Interfaces for Handline
Vague Retrieval Requests" ,
journal    =    "IEEE Database Engineering Bulletin - Special Issue
on Imprecision in Databases" ,
volume    =    "12" ,
number    =    "2" ,
month    =    "jun" ,
year    =    "1989" ,
pages    =    "54--63" ,
abstract=    "We discuss three user interfaces for situations
that involve vague retrieval requests: (1) BAROQUE, a browser for
relational databases; (2) VAGUE, a query interpreter for relational
databases that can handle neighborhood queries (formal queries with
similar-to comparators); and (3) FLEX, and adaptive interface to
relational databases that can service satisfactorily users with
different levels of expertise (users who submit queries of different
levels of correctness and well-formedness)." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( MOTRO90A,
key    =    "Motro" ,
author    =    "Motro, A." ,
title    =    "Accommodating imprecision in database systems:
issues and solutions" ,
journal    =    "sigmod" ,
volume    =    "19" ,
number    =    "4" ,
month    =    "dec" ,
year    =    "1990" ,
pages    =    "69--74" ,
abstract=    " Most database systems are designed under
assumptions of precision of both the data stored in their databases,
and the requests to retrieve data. In reality, however, these
assumptions are often invalid, and in recent years considerable
attention has been given to issues of imprecision in database systems.
In this paper we review the major solutions for accommodating
imprecision, and we describe issues that have yet to addressed,
offering possible research directions. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( MOTRO90B,
key    =    "Motro" ,
author    =    "Motro, A." ,
title    =    "Imprecision and incompleteness in relational
databases: survey" ,
journal    =    "Information and Software Technology" ,
volume    =    "32" ,
number    =    "9" ,
month    =    "nov" ,
year    =    "1990" ,
pages    =    "579--588" ,
keywords=    "databases, relational databases, fuzzy sets,
imprecision, incompleteness, modelling" ,
abstract=    "Most database systems are designed under
assumptions of precision and completeness of both the data they store
and the requests to retrieve data, even though in reality these
assumptions are often false. In recent years, considerable attention
has been given to issues of imprecision and incompleteness in
databases. The article surveys and compares the basis approaches that
address these issues in relational databases." ,
bibdate    =    "Mon Jul 22 14:20:59 1991" ,
owner    =    "curtis" ,
)

@article    ( MOTRO92,
key    =    "Motro" ,
author    =    "Motro, A." ,
title    =    "Annotating Answers with Their Properties" ,
journal    =    "sigmod" ,
volume    =    "21" ,
number    =    "1" ,
month    =    "mar" ,
year    =    "1991" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( MURTHY90,
key    =    "Murthy \& Kandel" ,
author    =    "Murthy, S. V. and Kandel, A." ,
title    =    "Fuzzy Sets and Typicality Theory" ,
journal    =    "Information Sciences" ,
volume    =    "51" ,
pages    =    "61--93" ,
year    =    "1990" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( NAQVI89,
key    =    "Naqvi, S. \& Rossi, F." ,
author    =    "Naqvi, S. and Rossi, F." ,
title    =    "Reasoning in Inconsistent Databases" ,
year    =    "1989" ,
number    =    "ACT-ST-269-89" ,
institution=    "MCC" ,
month    =    "jun" ,
)

@inproceedings    ( NAU89,
key    =    "Nau \& Wedekind" ,
author    =    "Nau, H. W. and Wedekind, H." ,
title    =    (Die Spezifikation von Nullwerten als Problem einer
wissensbasierten B\"uroautomatisierung) ,
booktitle=    (Proc. GI-Fachtagung, Datenbank-Systeme f\"ur
B\"uro, Technik und Wissenschaft, Germany) ,
address    =    (Z\"urich, Switzerland) ,
year    =    "1989" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( OLA89,
key    =    (Ola \& \"{O}zsoyo\v{g}lu) ,
author    =    (Ola, A. and \"{O}zsoyo\v{g}lu, G.) ,
title    =    "A Family of Incomplete Relational Database Models" ,
booktitle=    "vldb" ,
year    =    "1989" ,
pages    =    "23--31" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( OLA91,
key    =    "Ola" ,
author    =    "Ola, A." ,
title    =    "Modeling of Relational Databases with Exclusive
Disjunctions" ,
type    =    "Tech. Report" ,
institution=    "North Carolina State University" ,
year    =    "1991" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( OLA92,
key    =    "Ola" ,
author    =    "Ola, A." ,
title    =    "Relational Databases with Exclusive Disjunctions" ,
booktitle=    "Proceedings of the Eighth International Conference
on Data Engineering" ,
address    =    "Tempe, AZ" ,
month    =    "feb" ,
year    =    "1992" ,
pages    =    "328--336" ,
abstract=    "Disjunctive information in relational databases
are more likely to be of the exclusive OR variety than the inclusive
kind because of tuple uniqueness assumption in relations. There are
earlier works that deal with inclusive disjunction. In this paper, we
present a mechanism for representing exclusive disjunctive information
in database tables using various tuple types and a range for the count
of the number of tuples in the unknown relation denoted by a table.
The relational algebra operators are extended to take the new tables
as operands. Query evaluation in the extended model is sound (i.e., no
incorrect facts are derivable) and complete (i.e., all valid
conclusions are derivable) for relational algebra expressions
consisting of Projection, Difference, Cartesian Product or Selection
operators. We also give possible storage structures for storing the
base tables, and algorithms for inserting tuples into a table." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( OLA93,
key    =    "Ola \& Ozsoyoglu" ,
author    =    "Ola, A. and Ozsoyoglu, G." ,
title    =    "Incomplete Realational Database Models Based on
Intervals" ,
journal    =    "tkde" ,
volume    =    "5" ,
number    =    "2" ,
month    =    "apr" ,
year    =    "1993" ,
pages    =    "293--308" ,
abstract=    "In this paper, we utilize intervals for unknown
values in incomplete relational databases. We use tables to represent
unknown relations. First, we define three partial tuple types in a
table to specify incompleteness relationships among tuples of the same
table. For tuples of different tables, we distinguish between the
cases where incompleteness is introduced at the relation level, tuple
level, or attribute value level. Also, based on these relationships
among tuples in different tables, we present a family of incomplete
relational database models. For each of the models, we show that query
evaluation is sound (i.e., no incorrect results are derivable) in the
Imielinski-Lipski sense. None of the models is complete (i.e., all
valid conclusions are derivable) in the Imielinski-Lipski sense. We
briefy compare two of the models in the family with other approaches.
Considering each table tuple as a set of d-dimensional cubes, each
model in the family of models presented in this paper can be
considered and implemented as a geometric database model. We briefly
summarize the geometric operations and the primitive update semantics
that need to be utilized in such an implementation." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( ORLI90,
key    =    "Orli" ,
author    =    "Orli, R." ,
title    =    "Modeling Data For the Summary Database" ,
journal    =    "DATA BASE" ,
year    =    "1990" ,
pages    =    "11--19" ,
abstract=    "Summarization abstracts information and so reduces
flexibility. The challenge of summary database design is providing
adequately flexible information to meet the needs of the business
process it serves. This article addresses this challenge by examining
the basic forms of summarization as a set of model record forms, each
with advantages and disadvantages. The function of information implied
by these forms is described in terms of the business process model.
This model is the basis of a proposed data scheme that organizes
information ``top-down'' into the core of a flexible, effective,
summary database design." ,
bibdate    =    "Sun Apr  7 17:11:20 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( ORLOWSKA87,
key    =    "Orlowska" ,
author    =    "Orlowska, M. E." ,
title    =    "On Syntax and Semantics Related to Incomplete
Information Databases" ,
booktitle=    "Proceedings of the 4th South African Computer
Symposium" ,
address    =    "Pretoria, South Africa" ,
month    =    "jul" ,
year    =    "1987" ,
pages    =    "109--129" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( ORLOWSKA88,
key    =    "Orlowska" ,
author    =    "Orlowska, M. E." ,
title    =    "Two Interpretations of Queries to Incomplete
Information Databases" ,
journal    =    "South African Journal of Philosophy " ,
volume    =    "7" ,
number    =    "2" ,
year    =    "1988" ,
pages    =    "126--132" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( ORLOWSKA88A,
key    =    "Orlowska" ,
author    =    "Orlowska, M. E." ,
title    =    "On Incomplete Information Databases" ,
booktitle=    "Proceedings of the 4th International Conference on
Systems Research, Informatics and Cybernetics" ,
address    =    "Baden-Baden W.Germany" ,
year    =    "1988" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( OSBORN81,
key    =    "Osborn" ,
author    =    "Osborn, S." ,
title    =    "Insertions in a Multi-relation Database with Nulls" ,
booktitle=    "Proc. of COMPSAC81: IEEE Computer Society's Fifth
Int. Computer Software and applications Conference" ,
address    =    "Chicago, IL" ,
month    =    "nov" ,
year    =    "1981" ,
pages    =    "75--80" ,
abstract=    "In a relational database where functional
dependencies are to be maintained, insertions should be rejected if
they contradict functions embodied in the stored data. This paper
presents algorithms which perform such insertions, when acceptable,
for databases with no nulls, marked nulls, or unmarked nulls. In the
latter two cases, a three-phase algorithm is required. Factors
affecting the runtime of the algorithms are also considered." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( OSTERMANN87,
key    =    "Ostermann" ,
author    =    "Ostermann, P." ,
title    =    "Modal Logic and Incomplete Information" ,
year    =    "1987" ,
pages    =    "181--196" ,
booktitle=    "Proc. First Symposium on Mathematical Fundamentals
of Database Systems" ,
address    =    "Dresden, GDR" ,
month    =    "January" ,
)

@inproceedings    ( OSTERMANN87B,
key    =    "Ostermann" ,
author    =    "Ostermann, P." ,
title    =    "Interpr\'etation de l'information incompl\`ete en
logique modale" ,
booktitle=    "4\`eme conf\'erence Bases de Donn\'ees Avanc\'ees" ,
year    =    "1987" ,
pages    =    "279--296" ,
address    =    "Benodet, France" ,
)

@phdthesis    ( OSTERMANN88,
key    =    "Ostermann" ,
author    =    "Ostermann, P." ,
title    =    "Logiques Modales et Informations Incompl\`etes" ,
year    =    "1988" ,
month    =    "September" ,
school    =    "Toulouse" ,
)

@inproceedings    ( OZSOYOGLU87A,
key    =    (\"{O}zsoyo\v{g}lu) ,
author    =    (\"{O}zsoyo\v{g}lu, G.) ,
title    =    "Synthetic Query Response Construction in
Scientific Databases with Time Constraints and Incomplete Information" ,
booktitle=    "Proceedings of the International Conference on
Data Engineering" ,
organization=    "IEEE Computer Society" ,
publisher=    "IEEE Computer Society Press" ,
address    =    "Los Angeles, CA" ,
month    =    "feb" ,
year    =    "1987" ,
pages    =    "282" ,
abstract=    "Summary form only given. For some statistical and
scientific database applications, data-gathering and analysis
capabilities could be greatly enhanced if there were real-time/online
querying capabilities that return approximate responses to check the
quality of the generated data. In some experiments and applications,
the data gathered is so large that arguments have been raised for
processing the data on-the-fly during the execution of an experiment
or an application. Processing the data on-the-fly puts a time
constraint on query evaluation, i.e., queries must be processed in
fixed time-units and, for some experiments, in real-time. The efforts
at Case Western Reserve Univ. to build a methodology for synthetic
(approximate) query response construction (a) under real-time/online
time constraints, and (b) with real-time/online incomplete data
handling techniques that utilize statistical approximation are
considered." ,
bibdate    =    "Fri Oct  2 13:13:27 1987" ,
owner    =    "mckenzie" ,
)

@article    ( PEDRYCZ90,
key    =    "Pedrycz" ,
author    =    "Pedrycz, W." ,
title    =    "Relevancy of Fuzzy Models" ,
journal    =    "Information Services" ,
volume    =    "52" ,
pages    =    "285--302" ,
year    =    "1990" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( PIROTTE92,
key    =    "Pirotte \& Zim\'anyi" ,
author    =    "Pirotte, A. and Zim\'anyi, E." ,
title    =    "Imperfect Knowledge in Databases" ,
type    =    "RR" ,
number    =    "92-36" ,
institution=    "Unit\'e d'Informatique, Universit\'e de Louvain,
Belgium" ,
year    =    "1992" ,
month    =    "oct" ,
abstract=    "The field of imperfect knowledge (i.e., uncertain,
imprecise, incomplete) is characterized by: (1) an active research
area largely within relational theory; (2) a great variety of
approaches that are not easily comparable, and (3) few practically
usable results because of the inherent complexity of representing and
manipulating imperfect knowledge. This paper draws together and
analyzes a number of proposals from the literature, and it identifies
several research issues. Our aim was to give a unifying overview by
formulating the database semantics both with a model-theoretic flavor
(sets of possible worlds) and with a proof-theoretic flavor (sets of
first-order formulas). Besides the relational model, we briefly
describe some works on non-first normal form relations and the
universal relation model." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( PRADE82A,
key    =    "Prade" ,
author    =    "Prade, H." ,
title    =    "The connection between Lipski's approach to
incomplete information data bases and Zadeh's possibility theory" ,
booktitle=    "Proceedings of the International Conference on
Systems Methodology" ,
address    =    "Washington, D.C." ,
month    =    "jan" ,
year    =    "1982" ,
pages    =    "402--408" ,
abstract=    "do not have article " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( PRADE84,
key    =    "Prade \& Testemale" ,
author    =    "Prade, H. and Testemale, C." ,
title    =    "Generalizing database relational algebra for the
treatment of incomplete or uncertain information and vague queries" ,
journal    =    "Information Sciences" ,
volume    =    "34" ,
year    =    "1984" ,
pages    =    "115--143" ,
abstract=    "do not have article " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( PRADE85,
key    =    "Prade" ,
author    =    "Prade, H." ,
title    =    "Lipski's approach to Incomplete Information Data
Bases restated and generalized in the setting of Zadeh's Possibility
Theory" ,
journal    =    "Information Systems" ,
volume    =    "9" ,
number    =    "1" ,
year    =    "1985" ,
pages    =    "27--42" ,
bibdate    =    "Mon Apr  1 15:18:35 1991" ,
owner    =    "curtis" ,
abstract=    "The main purpose of this paper is to make clear
the connection between Lipski's approach to incomplete information
databases and Zadeh's possibility theory which both appeared recently,
quite simultaneously, but in different contexts. Lipski's approach is
extended by introducing [0,1]-valed levels of possibility in order to
take into account the fact that our incomplete knowledge about
properties of objects in databases may be based on soft (non-binary)
information or on statistical-like data. Moreover, possibility theory,
enlarged by the introduction of the concept of necessity, seems easier
to manipulate that the semantics of usual modal logic used by Lipski.
The problems of dependencies, of ``yes--no'' queries or of queries
involving the cardinalities of specified sets when available
information is incomplete are considered. Two illustrative examples
are dealt with." ,
)

@incollection    ( PRADE87,
key    =    "Prade \& Testemale" ,
author    =    "Prade, H. and Testemale, C." ,
title    =    "Representation of Soft Constraints and Fuzzy
Attribute Values by Means of Possibility Distributions in Databases" ,
booktitle=    "The Analysis of Fuzzy Information" ,
editor    =    "J. Bezdek" ,
publisher=    "CRC Press" ,
address    =    "Boca Raton, FL" ,
year    =    "1987" ,
volume    =    "2" ,
pages    =    "213--229" ,
abstract=    "do not have article " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( PRADE87A,
key    =    "Prade \& Testemale" ,
author    =    "Prade, H. and Testemale, C." ,
title    =    "Fuzzy Relational Databases: Representational
Issues and Reduction using Similarity Measures" ,
journal    =    "Journal of the American Society for Information
Science" ,
volume    =    "38" ,
number    =    "2" ,
month    =    "mar" ,
year    =    "1987" ,
pages    =    "118--126" ,
abstract=    "The proposed similarity measure, based on a fuzzy
Hausdorff distance, estimates the mismatch between two possibility
distributions. When several items have sufficiently similar values for
each attribute in a relation, the reduction is performed by taking for
each attribute the union of these similar values. The consequences of
the reduction process on query evaluation are studied." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( PRADE89,
key    =    "Prade \& Testemale" ,
author    =    "Prade, H. and Testemale, C." ,
title    =    "The Possible Approach to Handling of Imprecision
in Database Systems" ,
journal    =    "IEEE Database Engineering Bulletin - Special Issue
on Imprecision in Databases" ,
volume    =    "12" ,
number    =    "2" ,
month    =    "jun" ,
year    =    "1989" ,
pages    =    "4--10" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( PRADE93A,
key    =    "Prade" ,
author    =    "Prade, H." ,
title    =    "Annotated Bibliography on Fuzzy Information
Processing" ,
booktitle=    "Readings on Fuzzy Sets in Intelligent Systems" ,
editor    =    "Dubois, D., Prade, H., and Yager, R." ,
publisher=    "Morgan \& Kaufmann" ,
year    =    "1993" ,
abstract=    "none" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( RABITTI90,
key    =    "Rabitti \& Savino" ,
author    =    "Rabitti, F. and Savino, P." ,
title    =    "Retrieval of Multimedia Documents by Imprecise
Query Specification" ,
booktitle=    "Proceedings of the International Conference on
Extending Database Technology" ,
address    =    "Venice, Italy" ,
year    =    "1990" ,
pages    =    "203--218" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( RAJU86,
key    =    "Raju \& Majumdar" ,
author    =    "Raju, K. V. S. V. N. and Majumdar, A." ,
title    =    "Fuzzy Functional Dependencies in Fuzzy Relations" ,
booktitle=    "International Conference on Data Engineering" ,
address    =    "Los Angeles, CA" ,
month    =    "feb" ,
year    =    "1986" ,
pages    =    "312--319" ,
abstract=    "do not have article " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( RAJU87,
key    =    "Raju \& Majumdar" ,
author    =    "Raju, K. V. S. V. N. and Majumdar, A." ,
title    =    "The Study of Joins in Fuzzy Relational Databases" ,
journal    =    "Fuzzy Sets and Systems" ,
volume    =    "21" ,
number    =    "1" ,
year    =    "1987" ,
pages    =    "19--34" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@unpublished    ( RAJU87A,
key    =    "Raju \& Majumdar" ,
author    =    "Raju, K. V. S. V. N. and Majumdar, A." ,
title    =    "Design and implementation of a fuzzy relational
database system" ,
year    =    "1987" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( RAJU88,
key    =    "Raju \& Majumdar" ,
author    =    "Raju, K. V. S. V. N. and Majumdar, A." ,
title    =    "Fuzzy Functional Dependencies and Lossless Join
Decomposition of Fuzzy Relational Database Systems" ,
journal    =    "tods" ,
volume    =    "13" ,
number    =    "2" ,
year    =    "1988" ,
pages    =    "129--166" ,
keywords=    "functional dependency, fuzzy functional
dependency, fuzzy logic, fuzzy measure, fuzzy relation, inference
axiom, lossless join, membership function, relational database" ,
abstract=    "This paper deals with the application of fuzzy
logic in a relational database environment with the objective of
capturing more meaning of the data. It is shown that with suitable
interpretations for the fuzzy membership functions, a fuzzy relational
data model can be used to represent ambiguities in data values as well
as impreciseness in the association among them. Relational operators
for fuzzy relations have been studied, and applicability of fuzzy
logic in capturing integrity constraints has been investigated. By
introducing a fuzzy resemblance measure EQUAL for comparing domain
values, the definition of classical functional dependency has been
generalized to fuzzy functional dependency ({\bf ff}d. The implication
problem of {\em ff}ds has been examined and a set of sound and
complete inference axioms has been proposed. Next, the problem of
lossless join decomposition of fuzzy relations for a given set of
fuzzy functional dependencies is investigated. It is proved that with
a suitable restriction on EQUAL, the design theory of a classical
relational database with functional dependencies can be extended to
fuzzy relations satisfying fuzzy functional dependencies." ,
bibdate    =    "Mon Apr  1 15:18:35 1991" ,
owner    =    "curtis" ,
)

@article    ( RAMIREZ90,
key    =    "Ramirez et al." ,
author    =    "Ramirez, R. G. and Dattero, R. and Choobineh, J." ,
title    =    "Extension of Relational Views to derived relations
with Exceptions" ,
year    =    "1990" ,
journal    =    "Information Systems" ,
volume    =    "15" ,
pages    =    "321--333" ,
number    =    "3" ,
)

@inproceedings    ( READ92,
key    =    "Read" ,
author    =    "Read, R." ,
title    =    "A Multi-Resolution Relational Data Model" ,
booktitle=    "vldb" ,
address    =    "Vancouver, Canada" ,
year    =    "1992" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( REITER83,
key    =    "Reiter" ,
author    =    "Reiter, R." ,
title    =    "A Sound and Sometimes Complete Query Evaluation
Algorithm for Relational Databases with Null Values" ,
type    =    "Technical Report" ,
institution=    "Department of Computer Science, University of
British Columbia" ,
year    =    "1983" ,
month    =    "jun" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@incollection    ( REITER84,
key    =    "Reiter" ,
author    =    "Reiter, R." ,
title    =    "Towards a Logical Reconstruction of Relational
Database Theory" ,
booktitle=    "On Conceptual Modeling: Perspectives from
Artificial Intelligence Databases and Programming Languages" ,
editor    =    "M. Brodie, J. Mylopoulos, and J.W. Schmidt" ,
publisher=    "Springer-Verlag" ,
address    =    "Berlin and New York" ,
year    =    "1984" ,
pages    =    "191--238" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( REITER86,
key    =    "Reiter" ,
author    =    "Reiter, R." ,
title    =    "A Sound and Sometimes Complete Query Evaluation
Algorithm for Relational Databases with Null Values" ,
journal    =    "jacm" ,
volume    =    "33" ,
number    =    "2" ,
year    =    "1986" ,
pages    =    "349--370" ,
keywords=    "completeness proofs, first-order logic, integrity
constraints, null values, query evaluation, relational algebra,
relational databases, soundness proofs" ,
abstract=    "A sound and, in certain cases, complete method is
described for evaluating queries in relational databases with null
values where these nulls represent existing but unknown individuals.
The soundness and completeness results are proved relative to a
formalization of such databases as suitable theories of first-order
logic. Because the algorithm conforms to the relational algebra, it
may easily be incorporated into existing relational systems." ,
bibdate    =    "Mon Apr  1 15:18:35 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( REITER90,
key    =    "Reiter" ,
author    =    "Reiter, R." ,
title    =    "What should a database know?" ,
year    =    "1990" ,
pages    =    "96--113" ,
booktitle=    "Proceedings of the Symposium on Computational
Logic" ,
address    =    "Brussels" ,
)

@article    ( ROSS88,
key    =    "Ross \& Topor" ,
author    =    "Ross, K. A. and Topor, R. W." ,
title    =    "Inferring negative information from disjunctive
databases" ,
journal    =    "Journal of Automated Reasoning" ,
volume    =    "4" ,
number    =    "4" ,
month    =    "dec" ,
year    =    "1988" ,
pages    =    "397--424" ,
abstract=    "We propose criteria that any rule for inferring
negative information from disjunctive databases should satisfy, and
examine existing rules from this viewpoint. We present a new inference
rule, the 'disjunctive database rule' (DDR), and compare it to
existing rules with respect to the criteria. In particular, the DDR is
equivalent to the CWA for definite databases, it infers no more
negative information than the GCWA, and it interprets disjunction
inclusively rather than exclusively. We generalize the DDR to a class
of layered databases, describe an implementation of the DDR, 'negation
as positive failure', and study its soundness and completeness
properties." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( ROTH85,
key    =    "Roth et al." ,
author    =    "Roth, M. A. and Korth, H. F. and Silberschatz, A." ,
title    =    "Null Values in Non-1NF Relational Databases" ,
type    =    "Technical Report" ,
number    =    "TR-85-32" ,
institution=    "University of Texas at Austin" ,
year    =    "1985" ,
month    =    "dec" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( ROTH89,
key    =    "Roth et al." ,
author    =    "Roth, M. A. and Korth, H. F. and Silberschatz, A." ,
title    =    "Null Values in Nested Databases" ,
journal    =    "Acta Informatica" ,
volume    =    "26" ,
year    =    "1989" ,
pages    =    "615--642" ,
abstract=    "The desire to extend the applicability of the
relational model beyond traditional data-processing applications has
stimulated interest in nested or non-first normal form relations in
which the attributes of a relation can take on values which are sets
or even relations themselves. In this paper, we study the role of null
values in the nested relational model using an open world assumption.
We extend the traditional theory and study the properties of extended
operators for nested relations containing nulls. The no-information,
unknown, and non-existent interpretation of nulls are discussed and
the meaning of ``empty set'' is clarified. Finally, contrary to
several previous results, we determine that the traditional
axiomatization of functional and multivalued dependencies is valid in
the presence of nulls." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( ROTH91,
key    =    "Roth et al." ,
author    =    "Roth, M. A. and Korth, H. F. and Silberschatz, A." ,
title    =    "Addendum to Null Values in Nested Relational
Databases" ,
journal    =    "Acta Informatica" ,
volume    =    "28" ,
year    =    "1991" ,
pages    =    "607--610" ,
abstract=    "We define a new operator, decomposition
projection, and show that extended projection is a precise
generalization of decomposition projection with respect to unnesting,
and that null-extended projection is a precise generalization of
decomposition projection with respect to unnesting and PNF possibility
function POSS*." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( ROYER91,
key    =    "Royer" ,
author    =    "Royer, V." ,
title    =    "The Semantics of Incomplete Databases as an
Expression of Preferences" ,
journal    =    "Theoretical Computer Science" ,
volume    =    "78" ,
number    =    "1" ,
month    =    "jan" ,
year    =    "1991" ,
pages    =    "113--136" ,
abstract=    "We address the problem of incomplete information
in deductive databases from a semantic point of view. We want to treat
the problem in a homogeneous way, using a formalism which can handle
different types of incompleteness. We argue that it is convenient to
define an incomplete database as a double entity; an underlying
incomplete database together with selection criteria, formally some
preference relation on the set of models of the underlying database,
intended to reduce the incompleteness. Such an idea has been already
exploited in the Perfect Model semantics of Negation as Failure in the
stratified databases. We propose another notion of preference which
induces a stronger selection of models and captures an intuitive
process of ``making choices'' in disjunctive databases. We study both
the declarative and the operational semantics for this notion of
preference." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( RUNDENSTEINER87,
key    =    "Rundensteiner et al." ,
author    =    "Rundensteiner, E. A. and Hawkes, L. W. and
Bandler, W." ,
title    =    "Set-valued Temporal Knowledge Representation for
Fuzzy Temporal Retrieval in ICAI" ,
booktitle=    "Proceedings of NAFIPS, the North American Fuzzy
Info. Proc. Society`87" ,
month    =    "may" ,
year    =    "1987" ,
abstract=    "The goal of this paper is to develop some general
concepts of relevance to the Student Record Component of an
Intelligent Computer-Assisted Instruction system (ICAI). The Student
Record (SR) is an essential part of any ICAI system, since its task is
to capture the system's knowledge about the student in general, and
his abilities in the domain to be taught and his development over time
during the whole sequence of sessions in particular. This paper
proposes a relational representation as an underlying model for a
Student Record and then extends this by allowing a set-valued
extension of the representation and by finally also adding temporal
aspects to this relational representation. The impact of these two
enhancements of the relational data model on the representation and on
the manipulation is analyzed; and then the relational algebra, a query
language for the relational data model, is extended to cope with these
aspects. The result is a fuzzy temporal retrieval. An essential
feature of this approach is that the operations of this query language
default to their crisp non-temporal counterparts if no fuzzy or
temporal extensions are specified in them. Altogether, a set-valued
temporal relational representation schema with a fuzzy temporal
retrieval is presented, which is claimed to be of use as a knowledge
representation schema for other Artificial Intelligence (AI)
applications. It is assumed that the reader has a basic understanding
of fuzzy set and relational database theory." ,
bibdate    =    "Wed Apr  1 15:20:41 1992" ,
owner    =    "curtis" ,
)

@inproceedings    ( RUNDENSTEINER89A,
key    =    "Rundensteiner \& Bic" ,
author    =    "Rundensteiner, E. A. and Bic, L." ,
title    =    "Towards Modeling Imprecision in Semantic Data
Models" ,
booktitle=    "Proceedings of the Third International Fuzzy Sys.
Ass. World Congress" ,
month    =    "aug" ,
year    =    "1989" ,
abstract=    "Semantic database systems model the environment
more accurately than the traditional models by providing powerful
modeling constructs. A logical next step in the development of these
expressive data models is to incorporate the capability to handle
imprecision inherent in real world data. Fuzzy set theory presents one
such framework for managing imprecision. This paper combines semantic
data models with fuzzy set theory by identifying various levels within
the data model at which imprecision can be introduced." ,
bibdate    =    "Wed Apr  1 15:20:41 1992" ,
owner    =    "curtis" ,
)

@article    ( RUNDENSTEINER89B,
key    =    "Rundensteiner et al." ,
author    =    "Rundensteiner, E. A. and Hawkes, L. W. and
Bandler, W." ,
title    =    "On Nearness Measures in Fuzzy Relational Data
Models" ,
journal    =    "International Journal of Approximate Reasoning" ,
volume    =    "3" ,
number    =    "3" ,
month    =    "jul" ,
year    =    "1989" ,
pages    =    "267--298" ,
keywords=    "fuzzy relational data model, fuzzy relations,
nearness measure, tolerance relation, resemblance relation" ,
abstract=    "It has been widely recognized that the imprecision
and incompleteness inherent in real-world data suggests a fuzzy
extension for information management systems. Various attempts to
enhance these systems by fuzzy extensions can be found in the
literature. Varying approaches concerning the fuzzification of the
concept of a relation are possible, two of which are referred to in
this article as the generalized fuzzy approach and the fuzzy-set
relational approach. In these enhanced models, items can no longer be
retrieved by merely using equality-check operations between constants;
instead, operations based on some kind of nearness measures to be
established for each domain for the evaluation of queries made upon
them. An investigation of proposed nearness measures, often fuzzy
equivalences, is conducted. The unnaturalness and impracticality of
these measures leads to the development of a new measure: the
resemblance relation, which is defined to be a fuzzified version of a
tolerance relation. Various aspects of this relation are analyzed and
discussed. It is also shown how the resemblance relation can be used
to reduce redundancy in fuzzy relational database systems." ,
bibdate    =    "Wed Apr  1 15:20:41 1992" ,
owner    =    "curtis" ,
)

@inproceedings    ( RUNDENSTEINER89C,
key    =    "Rundensteiner \& Bic" ,
author    =    "Rundensteiner, E. A. and Bic, L." ,
title    =    "Aggregates in Possibilistic Databases" ,
booktitle=    "vldb" ,
year    =    "1989" ,
abstract=    "Fuzzy set theory represents a uniform framework
for extending the relational database model to handle imprecision of
information found in the real world. None of the existing proposals
for data models handling imprecision has dealt with queries involving
aggregate operators. This paper presents a framework for handling
aggregates in the context of imprecise information. Two kinds of
aggregates, namely, scalar aggregates and aggregate functions, are
being supported. We consider three cases: aggregates within
approximate queries on precise data, aggregates within precisely
specified queries on possibilistic data, and aggregates within vague
queries on imprecise data. These extensions are based on fuzzy
set-theoretical concepts such as the extension principle and the
possibilistic expected value." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( RUNDENSTEINER89D,
key    =    "Rundensteiner \& Bic" ,
author    =    "Rundensteiner, E. A. and Bic, L." ,
title    =    "Semantic Database Models and Their Potential for
Capturing Imprecision" ,
booktitle=    "Proc. Int. Conf. of Management of Data (COMAD 89)" ,
address    =    "Hyderabad, India" ,
month    =    "nov" ,
year    =    "1989" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( RUNDENSTEINER92A,
key    =    "Rundensteiner \& Bic" ,
author    =    "Rundensteiner, E. A. and Bic, L." ,
title    =    "Evaluating aggregates in possibilistic relational
databases" ,
journal    =    "Data \& Knowledge Engineering" ,
volume    =    "7" ,
year    =    "1992" ,
pages    =    "239--267" ,
keywords=    "Scalar aggregates; aggregate functions;
partitioning function; relational database model; possibilistic
relational model; possibility theory; fuzzy set theory" ,
abstract=    "The need for extending information management
systems to handle the imprecision of information found in the real
world has been recognized. Fuzzy set theory together with possibility
theory represent a uniform framework for extending the relational
database model with these features. However, none of the existing
proposals for handling imprecision in the literature had dealt with
queries involving a functional evaluation of a set of items,
traditionally refered [sic] to as aggregation. Two kinds of aggregate
operators, namely, scalar aggregates and aggregate functions, exists.
Both are important for most real-world applications, and thus this
paper presents a framework for handling these two types of aggregates
in the context of imprecise information. We consider three cases,
specifically, aggregates within vague queries on precise data,
aggregates within precisely specified queries on possibilistic data,
and aggregates within vague queries on imprecise data. The consistency
of the proposed operations is shown. An extended operator is defined
to be consistent if it defaults to its classical counterpart when
evaluated on crisp data." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@incollection    ( RUSPINI82A,
key    =    "Ruspini" ,
author    =    "Ruspini, E." ,
title    =    "Possibilistic data structures for the
representation of uncertainty" ,
booktitle=    "Approximate Reasoning in Decision Analysis" ,
editor    =    "M.M. Gupta and E. Sanchez" ,
publisher=    "North-Holland" ,
address    =    "Amsterdam" ,
year    =    "1982" ,
pages    =    "411--415" ,
abstract=    "do not have article " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( RUSPINI82B,
key    =    "Ruspini" ,
author    =    "Ruspini, E. H." ,
title    =    "Possibility Theory Approaches for Advanced
Information Systems" ,
journal    =    "Computer" ,
publisher=    "IEEE" ,
volume    =    "9" ,
number    =    "2" ,
month    =    "sep" ,
year    =    "1982" ,
pages    =    "83--89" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( RUSPINI91,
key    =    "Ruspini" ,
author    =    "Ruspini, E. H." ,
title    =    "Approximate Reasoning: Past, Present, Future" ,
journal    =    "Information Sciences" ,
volume    =    "57--58" ,
year    =    "1991" ,
pages    =    "297--317" ,
abstract=    "This paper presents a personal view of the state
of the art in the representation and manipulation of imprecise and
uncertain information by automated processing systems. To contrast
their objectives and characteristics with the sound deductive
procedures of classical logic, methodologies developed for that
purpose are usually described as relying on approximate reasoning.
Using a unified descriptive framework, we will argue that, far from
being mere approximations of logically correct procedures, approximate
reasoning methods are also sound techniques that describe the
properties of a set of conceivable states of a real-world system. This
framework, which is bases on the logical notion of possible worlds,
permits the description of various approximate reasoning methods and
techniques and simplifies their comparison. More importantly, our
descriptive model facilitates the understanding of the fundamental
conceptual characteristics of the major methodologies. We examine
first the development of approximate reasoning methods from early
advances to the present state of the art, commenting also on the
technical motivation for the introduction of certain controversial
approaches. Our unifying semantic model is then introduced to explain
the formal concepts and structures of the major approximate reasoning
methodologies: classical probability calculus, the Dempster-Shafer
calculus of evidence, and fuzzy (possibilistic) logic. In particular,
we discuss the basic conceptual differences between probabilistic and
possibilistic approaches. Finally, we take a critical look at the
controversy about the need and utility for diverse methodologies, and
asses requirements for future research and development." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( SADRI91,
key    =    "Sadri" ,
author    =    "Sadri, F." ,
title    =    "Modeling Uncertainty in Databases" ,
booktitle=    "Proceedings of the International Conference on
Data Engineering" ,
organization=    "IEEE Computer Society" ,
publisher=    "IEEE Computer Society Press" ,
address    =    "Los Angeles, CA" ,
year    =    "1991" ,
pages    =    "122--131" ,
abstract=    "The problem of representing and manipulating
inaccurate data was recently studied. The approach was to record the
information sources confirming a piece of data along with that data,
and to manipulate this information when processing queries. Relational
algebra operations were extended to produce, together with answers to
queries, information regarding sources that contributed to the
answers. In this paper we present a semantic interpretation for the
extended relational model, and justify the previous results. We show
that extended relational algebra operations are {\em precise}, that
is, they produce exactly the same answers that we expect under the
semantic interpretation. We also review algorithms for computing the
reliability of answer to a query, and prove their correctness under
our semantic interpretation." ,
bibdate    =    "Wed Jul 31 13:13:27 1991" ,
owner    =    "curtis" ,
)

@incollection    ( SAGE87,
key    =    "Sage" ,
author    =    "Sage, A. P." ,
title    =    "On the management of information imperfection in
knowledge based systems" ,
booktitle=    "Information Processing and Management of
Uncertainty" ,
editor    =    "B. Bouchon and R. Yager" ,
publisher=    "Springer-Verlag" ,
address    =    "New York" ,
year    =    "1987" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( SAGIV81,
key    =    "Sagiv" ,
author    =    "Sagiv, Y." ,
title    =    "Can we use the universal instance assumption
without using nulls?" ,
booktitle=    "sigmod" ,
organization=    "acm" ,
publisher=    "ACM Press" ,
address    =    "Ann Arbor, Michigan" ,
year    =    "1981" ,
pages    =    "108--120" ,
abstract=    "We claim that the {\em representative instance} of
[Ho1,Va3] is a correct representation of the data stored in a database
even when the relations of the database are not the projections of a
single universal instance. If no constraint (other than functional and
join dependencies) is imposed on the data, then projections of the
representative instance cannot always be computed by lossless joins.
We show that if the database satisfies a modified foreign-key
constraint, then projections of the representative instance can be
computed by performing the union of several lossless joins. A class of
relations schemes for which no constraint is necessary is
characterized, and we show how to compute projections of the
representative instance for databases that belong to this class." ,
bibdate    =    "Wed Jul 31 14:17:36 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( SAKAMA90,
key    =    "Sakama" ,
author    =    "Sakama, C." ,
title    =    "Possible Model Semantics for Disjunctive Databases" ,
booktitle=    "Proc. of the Int. Conf. on Deductive and
Object-Oriented Databases (DOOD'90)" ,
address    =    "Kyoto, Japan" ,
month    =    "dec" ,
year    =    "1989" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( SANCHEZ89,
key    =    "Sanchez" ,
author    =    "Sanchez, E." ,
title    =    "Importance in knowledge systems" ,
journal    =    "Information Systems" ,
volume    =    "14" ,
number    =    "6" ,
year    =    "1989" ,
pages    =    "455--464" ,
abstract=    "In knowledge systems, pieces of information
(evidence, hypotheses, attributes, terms, documents, rules) are
usually assumed to carry equal importance and to be independent of
each other, although it might not actually be the case. Issues for a
logic of weighted queries, with possibility of also weighting
documents and logical connectors (in terms of intelligent retrieval,
for example) are presented here, using 'min' or t-norms, and soft
operators involving p-norms. This logic cannot be a conventional one
for, when introducing relative importance between concepts,
definitions are different for ANDed and ORed weighted queries. A
concept of `nought', a limit case of no-importance queries, and its
behaviour with fuzzy sets operations is developed, in particular the
notion of an extended membership is introduced. Finally it is shown,
with a biomedical example, how to combine importance with soft
matching in rule-based systems. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( SCHIEL87,
key    =    "Schiel" ,
author    =    "Schiel, U." ,
title    =    "Representation and Retrieval of Incomplete and
Temporal Information" ,
type    =    "TR" ,
number    =    "DSC-02/87" ,
institution=    "Universidade Federal Da Paraiba" ,
year    =    "1987" ,
month    =    "may" ,
abstract=    "The concept of incomplete information is analysed
in the context of information systems with time dimension. This leads
to the inclusion of imprecise temporal assertions. We distinguish
between negative, unknown, and imprecise information. A tabular
structure is proposed and two types of queries are considered: boolean
queries, retrieval queries." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( SCHONING91,
key    =    (Sch\"oning) ,
author    =    (Sch\"oning, H.) ,
title    =    (Praktische Behandlung von Nullwerten --
Realisierung im Molek\"ul-Atom-Datenmodell) ,
booktitle=    (Proc. GI-Fachtagung, Datenbank-Systeme f\"ur
B\"uro, Technik und Wissenschaft, Germany) ,
address    =    "Kaiserslautern, Germany" ,
year    =    "1991" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( SCIORE79,
key    =    "Sciore" ,
author    =    "Sciore, E." ,
title    =    "Null Values, Updates, and Normalizations in
Relational Databases" ,
type    =    "Technical Report" ,
institution=    "Department of Electrical Engineering and Computer
Science, Princeton University" ,
year    =    "1979" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@phdthesis    ( SHENG84,
key    =    "Sheng" ,
author    =    "Sheng, R. L." ,
title    =    "A Linguistic Approach to Temporal Information
Analysis" ,
school    =    "University of California, Berkeley" ,
address    =    "Berkeley, California" ,
month    =    "may" ,
year    =    "1984" ,
abstract=    "This dissertation presents a linguistic approach,
based on test-score semantics and fuzzy logic, to the problem of fuzzy
temporal inference in question answering systems. While several models
have been proposed for the analysis of historical information, little
research has been done satisfactorily on the manipulation of fuzzy
temporal quantifiers such as 'a few days ago,' which refers to
absolute count, and 'often,' which refers to relative count. In this
dissertation, the theory of possibility is taken as an appropriate
framework for dealing with such a problem. The first step of the
approach for statements with absolute-count temporal quantifiers only,
is to translate these statements into their corresponding possibility
assignment equations using test-score semantics. Time information
among events can then be inferred from these equations by deriving its
possibility distribution. The compositional rule of inference plays
the central role in solving the equations. The algorithm for computing
the compositional rule can be transformed into one similar to Gaussian
elimination for the solution of linear equations. This method is
straightforward but inefficient. An improved technique is proposed
which represents all quantifiers by fuzzy numbers and replaces the
rule of composition with fuzzy addition. With this technique the
desired possibility distribution can be obtained by applying a
generalized Warshall's algorithm on the Time-Relation-Matrix, which is
a representation for given information. As for quantifiers which refer
to relative count, such as 'often,' fuzzy multiplication will play the
primary role. Finally, all mechanisms amount to a fuzzy temporal
logic, which serves as an inference tool for temporal information
analysis. This computational approach to fuzzy temporal quantifiers
has the following advantages. 1) It subsumes those approaches based on
two valued logic as limiting cases. 2) It deals uniformly with the
relative and absolute time relations. 3) It is easy to implement. 4)
It can be generalized to apply to other quantifiers used in different
concepts such as temperature and distance." ,
bibdate    =    "Fri Dec 22 14:03:10 1989" ,
owner    =    "robyn" ,
)

@article    ( SHENOI89,
key    =    "Shenoi \& Melton" ,
author    =    "Shenoi, S. and Melton, A." ,
title    =    "Proximity Relations in the Fuzzy Relational
Database Model" ,
journal    =    "Fuzzy Sets and Systems" ,
volume    =    "31" ,
year    =    "1989" ,
pages    =    "285--296" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( SHENOI90,
key    =    "Shenoi et al." ,
author    =    "Shenoi, S. and Melton, A. and Fan, L. T." ,
title    =    "An Equivalence classes model of fuzzy relational
databases" ,
journal    =    "Fuzzy Sets and Systems" ,
volume    =    "38" ,
number    =    "2" ,
month    =    "nov" ,
year    =    "1990" ,
pages    =    "153--170" ,
abstract=    "Buckles and Petry have demonstrated that the
classical properties of uniqueness of tuple interpretations and
well-definedness of the relational algebra can be retained in the
fuzzy relational database model. The key to the preservation of these
properties is the fact that scalar domains with similarity relations
and the fuzzy number domains can be partitioned into equivalence
classes. The present authors show that the important properties of
classical relational databases (and of fuzzy relational databases) are
preserved in a generalized model built on equivalence relations on
finite database domains. Further, they generalize the notion of a
functional dependency to the fuzzy relational model." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( SHENOI90A,
key    =    "Shenoi \& Melton" ,
author    =    "Shenoi, S. and Melton, A." ,
title    =    "An Extended Version of the Fuzzy Relational
Database Model" ,
journal    =    "Information Sciences" ,
volume    =    "52" ,
number    =    "1" ,
year    =    "1990" ,
pages    =    "35--52" ,
abstract=    " The fuzzy relational database model proposed B.P.
Buckles and F.E. Petry is a formal method for organizing and using
fuzzy information in relational databases. The model possesses two key
properties that hold for classical relational databases: no two tuples
have identical interpretations, and each relational algebra operation
has a unique result. The orginal fuzzy relational database model was
based on similarity relations which were defined on finite scalar
domains. Buckles and Petry later extended the model to incorporate
fuzzy number domains; this extension was done without loss of
consistency with the representation or the relational algebra. In a
recent paper we have extended the original model to proximity
relations which generalize similarity relations; the key properties of
Buckles and Petry's model are preserved in the extension. In this work
we demonstrate that the existence of partitions on finite scalar
domains in the fuzzy relational model is the key to preserving the
important properties of the classical relational model. We explain how
proximity relations defined on finite scalar domains are used to
partition the domains. Further, we show that normal fuzzy sets can be
employed as domain values. These fuzzy sets become members of finite
scalar domains, and their characteristic functions are employed in
generating the proximity relations of the fuzzy relational database
model." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( SHIN88,
key    =    "Shin" ,
author    =    "Shin, D." ,
title    =    "Semantics for Handling Queries with Missing
Information" ,
booktitle=    "Proc. of the 9th Annual Int'l Conf. on Information
Systems" ,
address    =    "Minneapolis, MN" ,
month    =    "dec" ,
year    =    "1988" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( SHUM88,
key    =    "Shum \& Muntz" ,
author    =    "Shum, C. and Muntz, R." ,
title    =    "Implicit representation for extensional answers" ,
booktitle=    "Proceedings of the Second International Conference
on Expert Database Systems" ,
month    =    "apr" ,
year    =    "1988" ,
pages    =    "257--273" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( SIKLOSSY81,
key    =    "Sikl\'{o}ssy" ,
author    =    "Sikl\'{o}ssy, L." ,
title    =    "Efficient Query Evaluation in Relational Databases
with Missing Values" ,
journal    =    "Information Processing Letters" ,
volume    =    "13" ,
number    =    "4--5" ,
year    =    "1981" ,
pages    =    "160--163" ,
abstract=    "do not have article QA 76 I47 " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( SLOWINSKI89,
key    =    "Slowinski \& Stefanowski" ,
author    =    "Slowinski, R. and Stefanowski, J." ,
title    =    "Rough Classification in Incomplete Information
Systems" ,
journal    =    "Mathematical and Computer Modelling (Oxford)" ,
volume    =    "12" ,
number    =    "10--11" ,
year    =    "1989" ,
pages    =    "1347--1357" ,
abstract=    " The paper is concerned with the problems of rough
sets theory and rough classification of objects. It is a new approach
to problems from the field of decision-making, data analysis,
knowledge representation, expert systems etc. Several applications
(particularly in medical diagnosis and engineering control) confirm
the usefulness of the rough sets idea. Rough classification concerns
objects described by multiple attributes in a so-called information
system. Traditionally, the information system is assumed to be
complete, i.e. the descriptors are not missing and are supposed to be
precise. In this paper we investigate the case of incomplete
information systems, and present a generalization of the rough sets
approach which deals with missing and imprecise descriptors. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@incollection    ( SPIES88,
key    =    "Spies" ,
author    =    "Spies, M." ,
title    =    "A model for the management of imprecise queries in
relational databases" ,
booktitle=    "Uncertainty and Intelligent Systems" ,
editor    =    "Bouchon, B. and Saitta, L and Yager, R. R." ,
publisher=    "Springer Verlag" ,
address    =    "Berlin-New York" ,
year    =    "1988" ,
pages    =    "146--153" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( STEPHANOU87,
key    =    "Stephanou \& Sage" ,
author    =    "Stephanou, H. E. and Sage, A. P." ,
title    =    "Perspectives on imperfect information processing" ,
journal    =    "IEEE Transactions on Systems, Man and Cybernetics" ,
volume    =    "17" ,
number    =    "5" ,
year    =    "1987" ,
pages    =    "780--798" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( SUBRAHMANIAN90,
key    =    "Subrahmanian" ,
author    =    "Subrahmanian, V. S." ,
title    =    "Paraconsistent Disjunctive Deductive Databases" ,
booktitle=    "Proceedings of the 20th International Symposium on
Multiple-Valued Logic" ,
address    =    "Charlotte, NC" ,
month    =    "may" ,
year    =    "1990" ,
pages    =    "339--346" ,
abstract=    " The author develops a theory of distinctive logic
programming, with negations allowed to appear both in the head of a
clause and in the body. As such programs can easily contain
inconsistent information (with respect to the intuitions of two-valued
logic), this means that the formalism allows reasoning about systems
that are intuitively inconsistent but yet have models (in nonclassical
model theory). Such an ability is important because inconsistencies
may occur very easily during the design and development of deductive
databases and/or expert systems. The author also develops a theory of
disjunctive deductive databases that (perhaps) contain inconsistent
information. The author shows how to associate, with any such
database, an operator that maps MV-model states to MV-model states. It
is shown that this operator has a least fixed point which is identical
to the set of all variable- free disjunctions that are provable from
the database under consideration. A procedure to answer queries to
such databases is devised. Soundness and completeness results are
proved. The techniques introduced are fairly general. However, the
results are applicable to databases that are quantitative in nature. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( SUCHENEK89,
key    =    "Suchenek" ,
author    =    "Suchenek, M. A." ,
title    =    "Two applications of model-theoretic forcing to
Lipski's data bases with incomplete information" ,
journal    =    "Fundamenta Informatic\ae" ,
volume    =    "12" ,
number    =    "3" ,
month    =    "sep" ,
year    =    "1989" ,
pages    =    "269--287" ,
abstract=    " This paper concerns two aspects of incomplete
information in data bases: computations of answers to queries which
are externally interpreted in some incomplete first-order structures
with dependencies, and the proper treatment of modal operators in such
structures. We introduce the notion of an incomplete first-order
structure with dependencies which seems to be an adequate model of
data bases with incomplete information. We show that the widely
accepted implicit assumption that first-order models (of a data base)
have a unique domain, has no first-order consequences if the set of
premises (represented in the data base) contains only a finite amount
of information explicitly involving the elements of this domain. This
observation allows us to evaluate the degree of unsolvability of the
problem of answering externally interpreted queries in the incomplete
first-order structures. Moreover, we propose a forcing-based
definition of the internal interpretation of modal queries in such
structures, and investigate some of the properties of this
interpretation. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( TAHANI77,
key    =    "Tahani" ,
author    =    "Tahani, V." ,
title    =    "A Conceptual Framework for Fuzzy Query Processing
- A Step toward very Intelligent Database Systems" ,
journal    =    "Information Processing \& Management" ,
volume    =    "13" ,
year    =    "1977" ,
pages    =    "289--303" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( TAKAHASHI91,
key    =    "Takahashi" ,
author    =    "Takahashi, Y." ,
title    =    "A fuzzy query language for relational databases" ,
journal    =    "IEEE Transactions on Systems, Man and Cybernetics" ,
volume    =    "21" ,
number    =    "6" ,
month    =    "Nov-Dec" ,
year    =    "1991" ,
pages    =    "1576--1579" ,
abstract=    " A fuzzy query language (FQL) for relational
databases is proposed. FQL, constructed as an enhancement of the
relational domain calculus, has sufficient capability to represent all
four types of the fuzzy statements distinguished by the work of L. A.
Zadeh (1978). The idea for constructing FQL is in the formulation of
the fuzzy matching degrees that assigns the appropriate values in the
interval to any combination of fuzzy queries and tuples in relational
databases. FQL helps to provide a human-oriented interface to
relational databases that store a vast amount of information.
Furthermore, fuzzy expert systems are expected to be provided with the
facility to make use of fact data in relational databases through FQL.
In addition, FQL is a theoretical basis for systematically developing
a higher human-oriented interface with relational databases. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( TANAKA89,
key    =    "Tanaka et al." ,
author    =    "Tanaka, K. and Yoshikawa, M. and Ishihara, K." ,
title    =    "Schema design, views and incomplete information in
object-oriented databases" ,
journal    =    "Journal of Information Processing" ,
volume    =    "12" ,
number    =    "3" ,
year    =    "1989" ,
pages    =    "239--250" ,
abstract=    " 'Object-oriented computing' is one of the most
active research fields in computer science, and this notion has become
an important paradigm in the areas of programming languages,
artificial intelligence and databases. In the area of databases,
although the relational approach achieved a great success, the
weakness of this model has been also pointed out as the database
application area extends to CAD/CAM application and software version
control etc. As an alternative candidate of the relational approach,
much attention has been focussed on 'object-oriented database
(abbreviated by OODB)', and the OODBs have been investigated by
several researchers. However, the study of the OODB has just begun,
and there are few investigations about the database schema design in
the OODB. In this paper, we show fundamental ideas and methods to
achieve schema design, update propagation, view implementation and the
treatment of incomplete information in the OODB. Especially, we show
some methods written in Smalltalk-80 to perform these and also discuss
the weakness of Smalltalk-80 from the viewpoint of the OODB." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@phdthesis    ( TESTEMALE84,
key    =    "Testemale" ,
author    =    "Testemale, C." ,
title    =    "Un syst\`eme de traitement d'informations
incompl\`etes ou incertaines dans une base de donn\'ees relationnelle" ,
year    =    "1984" ,
school    =    "Universit\'e Paul Sabatier, Toulouse" ,
)

@article    ( TRIPATHY90,
key    =    "Tripathy \& Sexena" ,
author    =    "Tripathy, R. C. and Sexena, P. C." ,
title    =    "Multivalued dependencies in fuzzy relational
databases" ,
journal    =    "Fuzzy Sets and Systems" ,
volume    =    "38" ,
number    =    "3" ,
month    =    "dec" ,
year    =    "1990" ,
pages    =    "267--279" ,
abstract=    " We show that by using the theory of possibility
distribution, multivalued dependencies in fuzzy relations can be
expressed in the frame work of particularization. Another definition
of functional dependencies in a fuzzy relation is given in terms of
fuzzy Hamming weight. We have also discussed the validity of inference
rules for multivalued dependencies in fuzzy relations. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( TRVIELI89,
key    =    "Trvieli" ,
author    =    "Trvieli, A." ,
title    =    "Representation and Access of Uncertain Relational
Data" ,
journal    =    "IEEE Database Engineering Bulletin - Special Issue
on Imprecision in Databases" ,
volume    =    "12" ,
number    =    "2" ,
month    =    "jun" ,
year    =    "1989" ,
pages    =    "21--28" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( TSENG92,
key    =    "Tseng et al." ,
author    =    "Tseng, F. S.-C. and Chen, A. L. P. and Yang, W. P." ,
title    =    "Generalizing the Division Operation on Indefinite
Databases" ,
booktitle=    "Future Database'92, Proceedings of the Second
Far-East Workshop on Future Database Systems" ,
address    =    "Kyoto, Japan" ,
month    =    "apr" ,
year    =    "1992" ,
pages    =    "347--354" ,
abstract=    " Uncertain data in databases were originally
denoted as null values, which represent the meaning of ``values
unknown at present''. Grant generalized null values into partial
values to provide a more powerful notion. In this paper, an important
operation - division, is fully studied to handle partial values. Due
to the uncertainties of partial values, the extended divisions may
produce maybe tuples. To process this extended division, we decompose
a relation consisting of partial values into a set of relations
containing only definite values by employing the concepts of
interpretation. Bipartite graph matching techniques are then applied
to develop efficient algorithms for the extended division that handles
partial values. A refinement on the maybe result tuples of an extended
division is also discussed." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@incollection    ( UMANO82,
key    =    "Umano" ,
author    =    "Umano, M." ,
title    =    "FREEDOM-O: A fuzzy database system" ,
booktitle=    "Fuzzy Information and Decision Processes" ,
editor    =    "M.M. Gupta and E. Sanchez" ,
publisher=    "North-Holland" ,
address    =    "Amsterdam" ,
year    =    "1982" ,
pages    =    "339--349" ,
abstract=    "do not have article " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( UMANO83,
key    =    "Umano" ,
author    =    "Umano, M." ,
title    =    "Retrieval from fuzzy data base by fuzzy relational
algebra" ,
booktitle=    "Proc. IFAC Symposium, Fuzzy Information, Knowledge
Representation and Decision Processes" ,
address    =    "Marseille" ,
month    =    "jul" ,
year    =    "1983" ,
pages    =    "1--6" ,
abstract=    "do not have article " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( VANBEEK91,
key    =    "van Beek" ,
author    =    "van Beek, P." ,
title    =    "Temporal query processing with indefinite
information" ,
journal    =    "Artificial Intelligence in Medicine" ,
volume    =    "3" ,
number    =    "6" ,
month    =    "dec" ,
year    =    "1991" ,
pages    =    "325--339" ,
abstract=    " Time is an important aspect of information in
medical domains. In this paper, we adopt Allen's influential interval
algebra framework for representing temporal information. The interval
algebra allows the representation of indefinite and incomplete
information which is necessary in many applications. However,
answering interesting queries in this framework has been shown to be
almost assuredly intractable. We show that when the representation
language is sufficiently restricted we can develop efficient
algorithms for answering interesting classes of queries including: (i)
determining whether a formula involving temporal relations between
events is possibly true and necessarily true; and (ii) answering
aggregation questions where the set of all events that satisfy a
formula are retrieved. We also show, by examining applications of the
interval algebra discussed in the literature, that our restriction on
the representation language often is not overly restrictive in
practice. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( VANDENBERGHE89,
key    =    "Vandenberghe et al." ,
author    =    "Vandenberghe, R. and Van Schooten, A. and De
Caluwe, R. and Kerre, E. E." ,
title    =    "Some practical aspects of fuzzy database
techniques. An example." ,
booktitle=    "Fuzzy Databases - Second International Fuzzy
Systems Association Congress" ,
address    =    "Tokyo, Japan" ,
month    =    "jul" ,
year    =    "1989" ,
pages    =    "465--472" ,
abstract=    " Basically there are two approaches for dealing
with incomplete or imprecise information in the framework of
(relational) databases. B. Buckles and F. Petry introduced fuzzy
similarity relations in order to estimate to what extent possible
values of an attribute can be regarded as interchangeable. In the
approach of D. Dubois, H. Prade and C. Testemale possibility
distributions were used to represent all possible kinds of
incompletely or fuzzily known values. This paper describes the
application of a combination of both techniques. We focus on the very
specific domain of criminal investigation, especially on criminal
identification by means of a personal description. However, the
developed method can be applied to a lot of other domains, where a
similar sort of fuzziness and uncertainty shows up. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( VARDI86,
key    =    "Vardi" ,
author    =    "Vardi, M. Y." ,
title    =    "On the integrity of databases with incomplete
information" ,
booktitle=    "pods" ,
year    =    "1986" ,
pages    =    "252--266" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( VARDI86A,
key    =    "Vardi" ,
author    =    "Vardi, M. Y." ,
title    =    "Querying logical databases" ,
journal    =    "Journal of Computer and System Sciences" ,
volume    =    "33" ,
year    =    "1986" ,
pages    =    "142--160" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( VASSILIOU79,
key    =    "Vassiliou" ,
author    =    "Vassiliou, Y." ,
title    =    "Null values in database management--a denotational
semantics approach" ,
booktitle=    "sigmod" ,
organization=    "acm" ,
publisher=    "ACM Press" ,
address    =    "New York" ,
month    =    "May" ,
year    =    "1979" ,
pages    =    "162--169" ,
abstract=    "We start with a very brief description of the
many-valued logic approach to the formal treatment of null values in
data bases and show some problems that are encountered. In the second
part of the paper we present our approach, based on the Denotational
Semantics Theory. An informal introduction to the theory is given and
then the relational model is described in terms of the theory. Query
evaluations are defined as continuous functions and several examples
are presented. The formalization in the framework of Denotational
Semantics allows for a better understanding of the semantic problems
with null values. It also gives flexibility for alternatives in
acceptable semantic interpretations. We conclude with a presentation
of an algorithm for the evaluation of simple queries. This algorithm
users symbolic manipulations and it is more economical than the strict
application of the definition of query evaluations." ,
bibdate    =    "Wed Jul 31 14:17:36 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( VASSILIOU80,
key    =    "Vassiliou" ,
author    =    "Vassiliou, Y." ,
title    =    "Functional Dependencies and Incomplete Information" ,
booktitle=    "vldb" ,
month    =    "oct" ,
year    =    "1980" ,
pages    =    "260--269" ,
abstract=    "Functional dependencies play an important role in
relational database design. They are defined in the context of a
single relation which at all times must contain tuples with non-null
entries. In this paper we examine an extension of the functional
dependency interpretation to handle {\em null} values, that is,
entries in tuples that represent incomplete information in a
relational database. A complete axiomatization of inference rules for
extended functional dependencies is also presented. Only after having
such results is it possible to talk about decompositions and
normalization theory in a context of incomplete information. Finally,
we show that there are several practical advantages in using nulls and
a weaker notion of constraint satisfiability." ,
bibdate    =    "Wed Jul 31 14:17:36 1991" ,
owner    =    "curtis" ,
)

@techreport    ( VASSILIOU80A,
key    =    "Vassiliou" ,
author    =    "Vassiliou, Y." ,
title    =    "A Formal Treatment of Imperfect Information in
Database Management" ,
type    =    "Technical Report" ,
number    =    "CSRG-123" ,
institution=    "University of Toronto" ,
year    =    "1980" ,
month    =    "nov" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@phdthesis    ( VASSILIOU80B,
key    =    "Vassiliou" ,
author    =    "Vassiliou, Y." ,
title    =    "A Formal Treatment of Imperfection in Database
Management" ,
school    =    "University of Toronto" ,
address    =    "Toronto, Canada" ,
year    =    "1980" ,
bibdate    =    "Fri Dec 22 14:03:10 1989" ,
owner    =    "curtis" ,
)

@inproceedings    ( VITEK83,
key    =    "Vitek" ,
author    =    "Vitek, M." ,
title    =    "Fuzzy information and fuzzy time" ,
booktitle=    "Proc. IFAC Symp. Fuzzy Information, Knowledge
Representation and Decision Analysis" ,
address    =    "Marseille, France" ,
year    =    "1983" ,
pages    =    "159--162" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( VOUNG87,
key    =    "Voung \& Thuan" ,
author    =    "Voung, L. T. and Thuan, H." ,
title    =    "Retrieval from Fuzzy Database by Fuzzy Relational
Algebra" ,
journal    =    "MTA Sztaki Kozlmemenyek" ,
volume    =    "37" ,
year    =    "1987" ,
pages    =    "223--248" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( VOUNG89,
key    =    "Voung \& Thuan" ,
author    =    "Voung, L. T. and Thuan, H." ,
title    =    "Relational database extended by application of
fuzzy set theory and linguistic variables" ,
journal    =    "Computers and Artificial Intelligence" ,
volume    =    "8" ,
number    =    "2" ,
year    =    "1989" ,
pages    =    "153--168" ,
abstract=    " This paper introduces a relational model of fuzzy
databases, an extended version of Codd's relational model by applying
the fuzzy set theory and the linguistic variables. The interpretation
of the data and the evaluation of a query in this model are based on
the concept of the possibility distribution function proposed by L. A.
Zadeh and the concept of multivalued logic. The data dependencies in
this extended database are also studied. The concept of
n-decomposition of an extended relation is introduced. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( VRBSKY91,
key    =    "Vrbsky \& Liu" ,
author    =    "Vrbsky, S. V. and Liu, Jane W. S." ,
title    =    "An Object-oriented Query Processor that Produces
Monotonically Improving Approximate Answers" ,
booktitle=    "Proceedings of the International Conference on
Data Engineering" ,
address    =    "Kobe, Japan" ,
year    =    "1991" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( VRBSKY93,
key    =    "Vrbsky \& Liu" ,
author    =    "Vrbsky, S. V. and Liu, J. W. S." ,
title    =    "APPROXIMATE: A Query Processor that Produces
Monotonically Improving Approximate Answers" ,
journal    =    "tkde" ,
volume    =    "5" ,
number    =    "6" ,
month    =    "dec" ,
year    =    "1993" ,
pages    =    "1056--1068" ,
abstract=    "This paper describes APPROXIMATE, a query
processor that makes approximate answers available if part of the
database is unavailable or if there is not enough time to produce an
exact answer. The processor implements approximate query
processing--the accuracy of the approximate result produced improves
monotonically with the amount of data retrieved to produce the result.
The monotone query processing algorithm of APPROXIMATE works within a
standard relational algebra framework. APPROXIMATE maintains semantic
information for approximate query processing on an underlying level
and can be implemented on a relational architecture. We show how
APPROXIMATE is implemented to make effective use of the semantic
support and describe the additional overhead required by APPROXIMATE." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( WANG90,
key    =    "Wang et al." ,
author    =    "Wang, F. and Hall, G. B. and Subaryono" ,
title    =    "Fuzzy information representation and processing in
conventional GIS software: database design and application" ,
journal    =    "International Journal of Geographical Information
Systems" ,
volume    =    "4" ,
number    =    "3" ,
year    =    "1990" ,
pages    =    "261--283" ,
abstract=    "Currently used methods for representing
geographical information are inadequate because they do not tolerate
imprecision. This leads to information loss and inaccuracy in
analysis. Such expressive inadequacy is largely due to the underlying
membership concept of classical set theory. To improve information
processing in GIS research and application, an alternative membership
concept is required. In this paper, we explore the inadequacy imposed
upon geographical information representation by classical set theory
and address the problems of information loss. A fuzzy relational data
model is defined which is more representative for geographical
information. A GIS database for agricultural land resource management
is created by using the data model and a new technique for assessing
land suitability is developed. The fuzzy representation largely
facilitates data analysis in this GIS. The methods are tested with
data from North Java, Indonesia using a vector-based GIS software
package, Arc Info, and the analysis results are presented." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( WARDEN90,
key    =    "Warden" ,
author    =    "Warden, A." ,
title    =    "Into the unknown [database languages]" ,
journal    =    "Relational Journal (UK)" ,
number    =    "9" ,
month    =    "mar" ,
year    =    "1990" ,
pages    =    "7--12" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( WEDEKIND88,
key    =    "Wedekind" ,
author    =    "Wedekind, H." ,
title    =    "Null Values in DBS (in german)" ,
journal    =    "Informatik Spektrum" ,
volume    =    "11" ,
year    =    "1988" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( WEIYI89,
key    =    "Weiyi" ,
author    =    "Weiyi, L." ,
title    =    "The determining method about the conflict between
null constraints and the set of functional dependencies" ,
journal    =    "Journal of Computer Science \& Technology (Eng.
Lang. Ed.) (China)" ,
volume    =    "4" ,
number    =    "2" ,
month    =    "apr" ,
year    =    "1989" ,
pages    =    "116--125" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( WILLIAMS88,
key    =    "Williams et al." ,
author    =    "Williams, M. H. and Kong, Q. and Chen, G." ,
title    =    "Handling Incomplete Information in a Logic
Database" ,
booktitle=    "UK IT 88 Conference Publication" ,
address    =    "Swansea, United Kingdom" ,
month    =    "jul" ,
year    =    "1988" ,
pages    =    "224--227" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( WILLIAMS88A,
key    =    "Williams \& Kong" ,
author    =    "Williams, M. H. and Kong, Q." ,
title    =    "Incomplete Information in a Deductive Database" ,
journal    =    "Data \& Knowledge Engineering" ,
volume    =    "3" ,
number    =    "3" ,
month    =    "nov" ,
year    =    "1988" ,
pages    =    "197--220" ,
abstract=    " The problem of handling incomplete information
efficiently has been studied in the context of relational databases by
various workers. However, dealing with incomplete information in a
deductive database is a more difficult problem. This paper discusses
the problem of interpretation of incomplete information in a deductive
database and puts forward a model to assist in understanding the
different interpretations and their effect on the evaluation of
queries. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( WILLIAMS88B,
key    =    "Williams \& Nicholson" ,
author    =    "Williams, M. H. and Nicholson, K. A." ,
title    =    "An Approach to Handling Incomplete Information in
Databases" ,
year    =    "1988" ,
journal    =    "The Computer Journal" ,
volume    =    "31" ,
pages    =    "133--140" ,
number    =    "2" ,
)

@inproceedings    ( WILLIS86,
key    =    "Willis et al." ,
author    =    "Willis, H. L. and Northcote-Green, J. E. D. and
Tram, H. N." ,
title    =    "Computerized Distribution Planning: Data Needs and
Results with Incomplete Data" ,
booktitle=    "IEEE/PES 1986 Transmission and Distribution
Conference" ,
address    =    "Anaheim, CA" ,
month    =    "sep" ,
year    =    "1986" ,
abstract=    " Computerized distribution planning can contribute
to the design of efficient, low cost power systems. In some cases,
however, data or information required by computer programs may not be
available, may be too expensive to collect, or may be of suspect
quality. In such cases, the whole issue of computer application is
called into question. The authors investigate the performance of
several popular computerized distribution planning methods when
applied to incomplete data bases or data bases with large amounts of
error. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( WINSLETT86A,
key    =    "Winslett" ,
author    =    "Winslett, M." ,
title    =    "Updating Logical Databases Containing Null Values" ,
booktitle=    "Proceedings of the International Conference on
Database Theory" ,
publisher=    "Springer-Verlag" ,
address    =    "Rome, Italy" ,
editor    =    "Ausiello, G. and Atzeni, P." ,
month    =    "sep" ,
year    =    "1986" ,
pages    =    "421--435" ,
abstract=    "We show that it is natural to extend the concept
of database updates to encompass databases with incomplete information
in the form of null values, or tuple attribute values that are known
to exist but whose exact value is not known. Our approach embeds the
incomplete database and the updates in the language of mathematical
logic, which we believe has strong advantages over relational tables
and traditional data manipulation languages in the incomplete
information situation. We present semantics for our update operators,
and provide an algorithm to perform the operations. The computational
complexity of the algorithm is examined, and a lazy evaluation scheme
coupled with simple user-supplied cost limits is recommended to avoid
undesirable expense during execution. This paper extends results
presented elsewhere." ,
bibdate    =    "Wed Sep  2 15:26:11 1987" ,
owner    =    "mckenzie" ,
)

@phdthesis    ( WINSLETT87,
key    =    "Winslett" ,
author    =    "Winslett, M." ,
title    =    "Updating databases with incomplete information" ,
school    =    "Stanford University" ,
address    =    "Stanford, California" ,
month    =    "jan" ,
year    =    "1987" ,
bibdate    =    "Fri Dec 22 14:03:10 1989" ,
owner    =    "curtis" ,
)

@article    ( WINSLETT88,
key    =    "Winslett" ,
author    =    "Winslett, M." ,
title    =    "A Model-Based Approach to Updating Databases with
Incomplete Information" ,
journal    =    "tods" ,
volume    =    "13" ,
number    =    "2" ,
year    =    "1988" ,
pages    =    "167--196" ,
keywords=    "fuzzy and probabilistic reasoning, incomplete
information, uncertainty, updates" ,
abstract=    "Suppose one wishes to construct, use, and maintain
a database of facts about the real world, even though the state of
that world is only partially known. In the artificial intelligence
domain, this problem arises when an agent has a base set of beliefs
that reflect partial knowledge about the world, and then tries to
incorporate new, possibly contradictory knowledge into this set of
beliefs. In the database domain, one facet of this situation is the
well-known null values problem. We choose to represent such a database
as a logical theory, and view the models of the theory as representing
possible states of the world that are consistent with all known
information. How can new information be incorporated into the
database? For example, given the new information that ``{\em b} or
{\em c} is true,'' how can one get rid of all outdated information
about {\em b} and {\em c}, add the new information, and yet in the
process not disturb any other information in the database? In
current-day database management systems, the difficult and tedious
burden of determining exactly what to add and remove from the database
is placed on the user. The goal of our research was to relieve users
of that burden, by equipping the database management system with
update algorithms that can automatically determine what to add and
remove from the database. Under our approach, new information about
the state of the world is input to the database management system as a
well-formed formula that the state of the world is now known to
satisfy. We have constructed database update algorithms to interpret
this update formula and incorporate the new information represented by
the formula into the database without further assistance from the
user. In this paper we show how to embed the incomplete database and
the incoming information in the language of mathematical logic,
explain the semantics of our update operators, and discuss the
algorithms that implement these operators." ,
bibdate    =    "Sun Apr  7 17:11:20 1991" ,
owner    =    "curtis" ,
)

@unpublished    ( WINSLETT90A,
key    =    "Winslett-Wilkins" ,
author    =    "Winslett-Wilkins, M." ,
title    =    "An Approach to Representing and Updating Partial
Information" ,
note    =    "Stanford University, Computer Science Department" ,
)

@techreport    ( WONG80A,
key    =    "Wong" ,
author    =    "Wong, E." ,
title    =    "A Statistical Approach to Incomplete Information" ,
type    =    "Technical Report" ,
number    =    "CCA-80-01" ,
institution=    "Computer Corporation of America" ,
year    =    "1980" ,
month    =    "may" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( WONG82,
key    =    "Wong" ,
author    =    "Wong, E." ,
title    =    "A Statistical Approach to Incomplete Information
in Database Systems" ,
journal    =    "tods" ,
volume    =    "7" ,
number    =    "3" ,
month    =    "sep" ,
year    =    "1982" ,
pages    =    "470--488" ,
keywords=    "theory; incomplete information; missing values;
null values" ,
abstract=    "There are numerous situations in which a database
cannot provide a precise answer to some of the questions that are
posed. Sources of imprecision vary and include examples such as
recording errors, incompatible scaling, and obsolete data. In many
such situations, considerable prior information concerning the
imprecision exists and can be exploited to provide valuable
information for queries to which no exact answer can be given. The
objective of this paper is to provide a framework for doing so." ,
bibdate    =    "Mon May 20 16:00:37 1985" ,
)

@article    ( WONG90,
key    =    "Wong \& Leung" ,
author    =    "Wong, M. H. and Leung, K. S." ,
title    =    "A Fuzzy Database-Query Language" ,
journal    =    "Information Systems" ,
volume    =    "15" ,
number    =    "5" ,
year    =    "1990" ,
pages    =    "583--590" ,
keywords=    "Fuzzy query language, multicriteria decision
making, conflict resolution" ,
abstract=    "Selection conditions for conventional
database-query languages are not natural enough to express criteria
with fuzzy concepts. To choose some alternatives from a database
requires the techniques of multicriteria decision making or conflict
resolution. However, some traditional techniques in this area still
have some drawbacks, such as inefficiency and independency of
criteria. In this paper a fuzzy database-query language is presented
and its position in the area of multicriteria decisions making in
database applications is discussed and identified. The selection
constraints of this query language can accept both crispy and fuzzy
conditions." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( WONG91,
key    =    "Wong \& Yao" ,
author    =    "Wong, S. K. M. and Yao, Y. Y." ,
title    =    "A Probabilistic Inference Model for Information
Retrieval" ,
journal    =    "Information Systems" ,
volume    =    "16" ,
number    =    "3" ,
year    =    "1991" ,
pages    =    "301--321" ,
keywords=    "Information retrieval, inference, vector space
model, probabilistic model, relevance feedback, indexing, query
formulation" ,
abstract=    "Based on the epistemological view of probability,
a probabilistic inference model is proposed in this paper. It is
argued that some of the problems presented in the conventional
probabilistic models may be resolved if one takes the epistemological
view instead of the aleatory view of probability. The new model also
recognizes the close connections between probabilistic and
vector-based approaches. It is explicitly shown that both the standard
and generalized vector space models are special cases of the proposed
probabilistic inference model. Our method is applicable to any basic
concepts from an indexing scheme. Furthermore, it provides a
theoretical basis for the vector-based relevance feedback models, and
has the additional advantage that no ad hoc parameters are needed. The
new approach gives a plausible explanation for adopting a linear
measure (discriminant function) for decision making in general,
although our discussion is mainly focussed on information retrieval." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( YAGER82,
key    =    "Yager" ,
author    =    "Yager, R. R." ,
title    =    "A new approach to the summarization of data" ,
journal    =    "Information Sciences" ,
volume    =    "28" ,
number    =    "1" ,
month    =    "oct" ,
year    =    "1982" ,
pages    =    "69--86" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( YAGER86,
key    =    "Yager" ,
author    =    "Yager, R. R." ,
title    =    "On Incomplete and Uncertain Knowledge Bases" ,
booktitle=    "Expert Systems in Government Symposium" ,
address    =    "McLean, VA" ,
month    =    "oct" ,
year    =    "1986" ,
pages    =    "96--100" ,
abstract=    "A central function of the knowledge base of an
expert system is to represent the associations between variables
relevant to the domain of the system. The author suggests that an
experts' lack of complete knowledge of the underlying domain requires
the use of more sophisticated methods to represent these associations
than used in the past. He discusses the appropriateness of using the
theory of approximate reasoning for representing knowledge in expert
systems." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( YAGER87,
key    =    "Yager" ,
author    =    "Yager, R. R." ,
title    =    "Set-Based Representations of Conjunctive and
Disjunctive Knowledge" ,
journal    =    "Information Sciences" ,
volume    =    "41" ,
year    =    "1987" ,
pages    =    "1--22" ,
abstract=    "We look at the use of sets as a method of
representing information. We study the use of different set operators
to implement differenct semantic operations. Careful distinction is
made between conjunctive and disjunctive type information." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( YAGER91,
key    =    "Yager" ,
author    =    "Yager, R. R." ,
title    =    "Fuzzy Quotient Operators for Fuzzy Relational
Databases" ,
booktitle=    "Proc. International Fuzzy Engineering Symposium" ,
address    =    "Yokohama, Japan" ,
year    =    "1991" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( YAHYA85,
key    =    "Yahya \& Henschen" ,
author    =    "Yahya, A. and Henschen, L. J." ,
title    =    "Deduction in Non-{H}orn Databases" ,
year    =    "1985" ,
journal    =    "JAR" ,
volume    =    "1" ,
pages    =    "141--160" ,
)

@article    ( YAN88,
key    =    "Yan \& Jichao" ,
author    =    "Yan, Z. and Jichao, H." ,
title    =    "Data dependencies in database with incomplete
information" ,
journal    =    "Journal of Computer Science \& Technology (Eng.
Lang. Ed.) (China)" ,
volume    =    "3" ,
number    =    "2" ,
month    =    "apr" ,
year    =    "1988" ,
pages    =    "131--138" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( YANG91,
key    =    "Yang \& Lee" ,
author    =    "Yang, J. D. and Lee, Y. J." ,
title    =    "Characterization of unknown values with implicit
predicate" ,
journal    =    "Decision Support Systems" ,
volume    =    "7" ,
number    =    "2" ,
month    =    "may" ,
year    =    "1991" ,
pages    =    "133--144" ,
abstract=    " In general, null values are interpreted as
unknown value or inapplicable value. This paper proposes a new
approach for solving the unknown value problems with Implicit
Predicate (IP). The IP serves as a descriptor corresponding to a set
of the unknown values, thereby expressing the semantics of them. In
this paper, we demonstrate that the IP is capable of (1) enhancing the
semantic expressiveness of the unknown values. (2) entering incomplete
information into database and (3) exploiting the information and a
variety of inference rules in database to reduce the uncertainties of
the unknown values. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( YANG91A,
key    =    "Yang \& Lee" ,
author    =    "Yang, J. D. and Lee, Y. J." ,
title    =    "A sound and complete query evaluation for Implicit
Predicate which is a semantic descriptor of unknown values" ,
journal    =    "Information Processing Letters" ,
volume    =    "39" ,
month    =    "sep" ,
year    =    "1991" ,
pages    =    "283--289" ,
keywords=    "Information retrieval, unknown values, deductive
database" ,
abstract=    "none given" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( YAZICI90,
key    =    "Yazici" ,
author    =    "Yazici, A." ,
title    =    "Representing Imprecise Information in NF**2
Relations" ,
booktitle=    "IEEE Proceedings of Southeastcon '90 -
Technologies Today and Tomorrow" ,
address    =    "New Orleans, LA" ,
month    =    "apr" ,
year    =    "1990" ,
pages    =    "1026--1030" ,
abstract=    " A model which can represent imprecise information
and store it as an extension of normal-form (NF**2) relations with one
level of nesting is proposed. It is shown by example that the model is
more general than the ordinary NF**2 relational model. This generality
is accomplished by an operator that can manipulate imprecise data and
precise data and can have the same properties as the nest and the pack
operators defined for NF**2 relations. This operator, called the merge
operator, is defined. A representation framework for representing
incomplete data, including range values and various null values, is
also proposed. " ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@mastersthesis    ( YEO87,
key    =    "Yeo" ,
author    =    "Yeo, A." ,
title    =    "Sets in Relational Databases" ,
year    =    "1987" ,
address    =    "Department of Computer Science" ,
school    =    "Victoria University, Wellington, New Zealand" ,
)

@inproceedings    ( YIA92,
key    =    "Yia et al." ,
author    =    "Yia, Y. and Feng, Z. and Miller, M." ,
title    =    "A Multivalued Approach to handle nulls in RDB" ,
booktitle=    "Proc. 2nd Far-East Workshop on Future Database
Systems" ,
address    =    "Kyoto, Japan" ,
month    =    "apr" ,
year    =    "1992" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( YUAN88,
key    =    "Yuan \& Chiang" ,
author    =    "Yuan, L. Y. and Chiang, D." ,
title    =    "A Sound and Complete Query Evaluation Algorithm
for Relational Databases with Null Values" ,
booktitle=    "sigmod" ,
organization=    "acm" ,
publisher=    "ACM Press" ,
month    =    "may" ,
year    =    "1988" ,
pages    =    "74--81" ,
abstract=    "Reiter has proposed extended relational theory to
formulate relational databases with null values and presented a query
evaluation algorithm for such databases. However, due to indefinite
information brought by null values, Reiter's algorithm is sound but
not complete. In this paper, we first propose an extended relation to
represent indefinite information in relational databases. Then we
define an extended relational algebra for extended relations. Based on
Reiter's extended relational theory, and our extended relations and
the extended relational algebra, we present a sound and complete query
evaluation algorithm for relational databases with null values." ,
bibdate    =    "Sun Apr  7 17:11:20 1991" ,
owner    =    "curtis" ,
)

@article    ( YUE91,
key    =    "Yue" ,
author    =    "Yue, K." ,
title    =    "A More General Model For Handling Missing
Information In Relational DataBases Using A 3-Valued Logic" ,
journal    =    "sigmod" ,
publisher=    "ACM" ,
volume    =    "20" ,
number    =    "3" ,
month    =    "sep" ,
year    =    "1991" ,
pages    =    "43--49" ,
abstract=    "Codd proposed the use of two interpretations of
nulls to handle missing information in relational databases that may
lead to a 4-valued logic [Codd86, Codd87]. In a more general model,
three interpretations of nulls are necessary [Roth, Zani]. Without
simplification, this may lead to a 7-valued logic, which is too
complicated to be adopted in relational databases. For such a model,
there is no satisfactory simplification to a 4-valued logic. However,
by making a straightforward simplification and using some proposed
logical functions, a 3-valued logic can handle all three
interpretations." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( ZADEH89,
key    =    "Zadeh" ,
author    =    "Zadeh, L." ,
title    =    "Knowledge Representation in Fuzzy Logic" ,
journal    =    "tkde" ,
volume    =    "1" ,
number    =    "1" ,
year    =    "1989" ,
pages    =    "89--100" ,
abstract=    "The conventional approaches to knowledge
representation, e.g., semantic networks, frames, predicate calculus,
and Prolog, are based on bivalent logic. A serious shortcoming of such
approaches is their inability to come to grips with the issue of
uncertainty and imprecision. As a consequence, the conventional
approaches do not provide an adequate model for modes of reasoning
which are approximate rather than exact. Most modes of human reasoning
and all of common sense reasoning fall into this category. Fuzzy
Logic, which may be viewed as an extension of classical logical
systems, provides an effective conceptual framework for dealing with
the problem of knowledge representation in an environment of
uncertainty and imprecision. Meaning representation in fuzzy logic is
based on test-score semantics. In this semantics, a proposition is
interpreted as a system of elastic constraints, and reasoning is
viewed as elastic constraint propagation. Our paper presents a summary
of the basic concepts and techniques underlying the application of
fuzzy logic to knowledge representation and describes a number of
examples relating to its use as a computational system for dealing
with uncertainty and imprecision in the context of knowledge, meaning,
and inference." ,
bibdate    =    "Sun Apr  7 17:11:20 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( ZANIOLO82,
key    =    "Zaniolo" ,
author    =    "Zaniolo, C." ,
title    =    "Database Relations with Null Values (Extended
Abstract)" ,
booktitle=    "pods" ,
organization=    "acm" ,
address    =    "Los Angeles, CA" ,
month    =    "mar" ,
year    =    "1982" ,
pages    =    "27--33" ,
abstract=    "none given" ,
bibdate    =    "Sat Jan 21 12:31:24 1984" ,
)

@techreport    ( ZANIOLO83A,
key    =    "Zaniolo" ,
author    =    "Zaniolo, C." ,
title    =    "A Formal Treatment of Nonexistent Values in
Database Relations" ,
type    =    "Technical Report" ,
institution=    "bell" ,
year    =    "1983" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( ZANIOLO84,
key    =    "Zaniolo" ,
author    =    "Zaniolo, C." ,
title    =    "Database Relations with Null Values" ,
journal    =    "Journal of Computer and System Sciences" ,
volume    =    "28" ,
year    =    "1984" ,
pages    =    "142--166" ,
abstract=    "A new formal approach is proposed for modeling
incomplete database information by means of null values. The basis of
our approach is an interpretation of nulls which obviates the need for
more than one type of null. The conceptual soundness of this approach
is demonstrated by generalizing the formal framework of the relational
data model to include null values. In particular, the set-theoretical
properties of relations with nulls are studied and the definitions of
set inclusion, set union, and set difference are generalized. A simple
and efficient strategy for evaluating queries in the presence of nulls
is provided. The operators of relational algebra are then generalized
accordingly. Finally, the deep-rooted logical and computational
problems of previous approaches are reviewed to emphasize the superior
practicability of the solution." ,
bibdate    =    "Sun Apr  7 17:11:20 1991" ,
owner    =    "curtis" ,
)

@book        ( ZEMANKOVA-LEECH84,
key    =    "Zemankova-Leech \& Kandel" ,
author    =    "Zemankova-Leech, M. and Kandel, A." ,
title    =    "Fuzzy Relational Data Bases --- a Key to Expert
Systems" ,
publisher=    (T\"{U}V Rheinland) ,
series    =    "Interdisciplinary Systems Research Series" ,
address    =    (K\"{o}ln) ,
year    =    "1984" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( ZEMANKOVA85,
key    =    "Zemankova \& Kandel" ,
author    =    "Zemankova, M. and Kandel, A." ,
title    =    "Implementing Imprecision in Information Systems" ,
journal    =    "Information Sciences" ,
volume    =    "37" ,
year    =    "1985" ,
pages    =    "107--141" ,
abstract=    "The aim of data base management system designers
is to provide the user with the ability to store data that can be used
in deriving information satisfying the user's information needs.
Information provided by data bases is frequently used as an input in
decision making and problem solving in uncertain environments. Human
beings deal with uncertainty by applying approximate reasoning which
enables them to deal with uncertainty and imprecise, incomplete, or
vague information. Therefore, there is a need for information systems
and expert systems that allow representation and manipulation of
imprecise information in order to model human reasoning. Furthermore,
it is desirable that such systems provide means for
``individualization'' to reflect the user's perception of data and the
information requirements. The fuzzy relational data base (FRDB) model
presented in this paper is based on research in the fields of
relational data bases and theories of fuzzy sets and possibility. It
is designed to satisfy the need for individualization and imprecise
information processing. After introduction to the underlying theory,
the FRDB model architecture and query language are presented. Finally,
the possible applications of the FRDB in imprecise information
processing are discussed." ,
bibdate    =    "Sun Apr  7 17:11:20 1991" ,
owner    =    "curtis" ,
)

@article    ( ZEMANKOVA89,
author    =    "Zemankova, M." ,
title    =    "FIIS: A Fuzzy Intelligent Information System" ,
journal    =    "IEEE Database Engineering Bulletin - Special Issue
on Imprecision in Databases" ,
volume    =    "12" ,
number    =    "2" ,
month    =    "jun" ,
year    =    "1989" ,
pages    =    "11--20" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( ZEMANKOVA89A,
key    =    "Zemankova" ,
author    =    "Zemankova, M." ,
title    =    "FILIP. A fuzzy intelligent information system with
learning capabilities" ,
journal    =    "Information Systems" ,
volume    =    "14" ,
number    =    "6" ,
year    =    "1989" ,
pages    =    "473--486" ,
abstract=    " FILIP (fuzzy intelligent learning information
processing) system is designed with the goal to model human
information processing. The issues addressed are uncertain knowledge
representation and approximate reasoning based on fuzzy set theory,
and knowledge acquisition by 'being told' or by 'learning from
examples'. Concepts that can be 'learned' by the system can be
imprecise (fuzzy), or the knowledge can be incomplete. In the latter
case, FILIP uses the concept of similarity to extrapolate the
knowledge to cases that were not covered by examples provided by the
user. Concepts are stored in the knowledge base and employed in
intelligent query processing, based on flexible inference that
supports approximate matches between the data in the database and the
query. The architecture of FILIP is discussed, the learning algorithm
is described, and examples of the system's performance in the
knowledge acquisition and querying modes, together with its
explanatory capabilities are shown." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( ZHOU91,
key    =    "Zhou" ,
author    =    "Zhou, N." ,
title    =    "Representation and Processing of Uncertain
Information in Relational Databases" ,
booktitle=    "The 10th International Conference on the Entity
Relationship Approach" ,
address    =    "San Francisco, CA" ,
month    =    "oct" ,
year    =    "1991" ,
abstract=    "do not have article" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@article    ( ZICARI90,
key    =    "Zicari" ,
author    =    "Zicari, R." ,
title    =    "Incomplete Information in Object-Oriented
Databases" ,
journal    =    "sigmod" ,
volume    =    "19" ,
number    =    "3" ,
month    =    "sep" ,
year    =    "1990" ,
pages    =    "5--16" ,
abstract=    "We present a way to handle incomplete information
both at schema and object instance level in an object-oriented
database. Incremental schema design becomes possible with the
introduction of generic classes. Incomplete data in an object instance
is handled with the introduction of explicit null values in a similar
way as in the relational and nested relations data models." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( ZICARI92,
key    =    "Zicari" ,
author    =    "Zicari, R." ,
title    =    "Databases and Incomplete Information" ,
booktitle=    "Proc. Workshop on Uncertainty Management" ,
address    =    "Palma de Majorca, Spain" ,
month    =    "sep" ,
year    =    "1992" ,
abstract=    "do not have" ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@phdthesis    ( ZIMANYI92,
key    =    "Zim\'anyi" ,
author    =    "Zim\'anyi, E." ,
title    =    "Incomplete and Uncertain Information in Relational
Databases" ,
school    =    "Universit\'e Libre de Bruxelles" ,
address    =    "Brussells, Belgium" ,
month    =    "jul" ,
year    =    "1992" ,
abstract=    "In real life it is very often the case that the
available knowledge is {\it imperfect} in the sense that it represents
multiple possible states of the external world, yet it is unknown
which state corresponds to the actual situation of the world.
Imperfect knowledge can be of two different categories. Knowledge is
{\it incomplete} if it represents different states, one of which is
true in the external world. On the contrary, knowledge is {\it
uncertain} if it represents different states which may be satisfied or
are likely to be true in the external world. Imperfect knowledge can
be considered under two different perspectives: using either an {\it
algebraic} or a {\it logical} approach. We present both approaches in
relation with the standard relational model, providing the necessary
background for the subsequent development. The study of imperfect
knowledge has been an active area of research, in particular in the
context of relational databases. However, due to the complexity of
manipulating imperfect knowledge, little practical results have been
obtained so far. In this thesis we provide a survey of the field of
incompleteness and uncertainty in relational databases; it can be used
also as an introductory tutorial for understanding the intuitive
semantics and the problems encountered when representing and
manipulating such imperfect knowledge. The survey concentrates in
giving an unifying presentation of the different approaches and
results found in the literature, thus providing a state of the art in
the field. The rest of the thesis studies in detail the manipulation
of one type of incomplete knowledge, namely {\it disjunctive
information}, and one type of uncertain knowledge, namely {\it
probabilistic information}. We study both types of imperfect knowledge
using similar approaches, that is through an algebraic and a logical
framework. The relational algebra operators are generalized for
disjunctive and probabilistic relations, and we prove the correctness
of these generalizations. In addition, disjunctive and probabilistic
databases are formalized using appropriate logical theories and we
give sound and complete query evaluation algorithms. A major
implication of these studies is the conviction that viewing
incompleteness and uncertainty as different facets of the same problem
would allow to achieve a deeper understanding of imperfect knowledge,
which is absolutely necessary for building information systems capable
of modeling complex real-life situations." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( ZIMANYI92A,
key    =    "Zim\'anyi" ,
author    =    "Zim\'anyi, E." ,
title    =    "Query Evaluation in Probabilistic Databases" ,
type    =    "RR" ,
number    =    "92-01" ,
institution=    "INFODOC, Universit\'e Libre de Bruxelles, Belgium" ,
year    =    "1992" ,
month    =    "sep" ,
abstract=    "This paper describes a generalization of the
relational model in order to capture and manipulate a particular type
of probabilistic information. Probabilistic databases are formalized
by means of probabilistic logic theories based on a probabilistic
first-order language proposed by Halpern. A sound a complete method is
described for evaluating queries in probabilistic theories. The
generalization proposed can be incorporated into existing relational
systems with the addition of a component for the manipulation of
propositional formulas." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@techreport    ( ZIMANYI92B,
key    =    "Zim\'anyi" ,
author    =    "Zim\'anyi, E." ,
title    =    "Probabilistic Relational Databases" ,
type    =    "RR" ,
number    =    "92-02" ,
institution=    "INFODOC, Universit\'e Libre de Bruxelles, Belgium" ,
year    =    "1992" ,
month    =    "oct" ,
abstract=    "This paper describes a generalization of the
relational model in order to capture and manipulate a particular type
of probabilistic information. We define probabilistic relations and
define their semantics. However, it is not possible to define
relational operators over probabilistic relations which yield
semantically correct results for arbitrary relational expressions. For
this reason, we define another kind of relations called {\it trace
relations} or, briefly, {\it t-relations}. Once the semantics of these
relations is defined, we prove that a relational algebra over
t-relations can be correctly defined. Thus, manipulating probabilistic
databases implies translating the database into t-relations, applying
relational operators over the t-relations, and translating the results
obtained into a probabilistic relation. The generalization proposed
can be incorporated into existing relational systems with the addition
of a component for manipulating propositional formulas." ,
bibdate    =    "Mon Apr  1 15:20:41 1991" ,
owner    =    "curtis" ,
)

@inproceedings    ( ZVIELI86,
key    =    "Zvieli \& Chen" ,
author    =    "Zvieli, A. and Chen, P." ,
title    =    "Entity-Relationship Modeling and Fuzzy Databases" ,
booktitle=    "Proceedings of the Second International Conference
on Data Engineering" ,
year    =    "1986" ,
pages    =    "320--327" ,
abstract=    "This work describes an integration of an
entity/relationship model an fuzzy databases. It outlines a formal
model for representing fuzziness in the ER model, and sketchs a
version of the ER algebra, adapted to manipulating fuzzy databases." ,
bibdate    =    "Wed Jul 31 09:59:23 1991" ,
owner    =    "curtis" ,
)

@Comment (BIBSETS
)