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\begin{document}

\bibliographystyle{ieeetr}

\title{Internet Information Discovery and Retrieval Tools -\\
Cost Effective Building Blocks for Asset Libraries}

\author{Timothy Stockwell\\
\\
The MITRE Corporation\\
MS-Z381\\
7525 Colshire Drive\\
McLean, VA 22102-3481\\
Tel: (703) 883-6695\\
Email: tim@mitre.org\\
\\
Mark Krause\\
\\
The MITRE Corporation\\
MS-W273\\
7525 Colshire Drive\\
McLean, VA 22102-3481\\
Tel: (703) 883-7642\\
Email: mkrause@mitre.org\\
}
\date{}

\maketitle

\begin{abstract}
The MITRE Corporation's Center for Advanced Aviation System Development
(CAASD) is addressing the issue of institutionalizing reuse within the
corporation.
Implementation of a distributed, heterogeneous asset library has been
recognized as a critical step in achieving the vision of
institutionalized information reuse.
Recent advances in the field of network information discovery and retrieval
technology have led to the CAASD development of
a reuse library mechanism, at minimal cost,
using widely available Internet resources.  This position
paper supports the use of Internet resource discovery tools as
cost-effective building blocks for implementing distributed, heterogeneous asset
libraries.

\vspace{0.2in}
\noindent
{\bf Keywords:} library, architecture, interoperability, standards, full-text
indexing, network information discovery and retrieval, Internet Gopher, WAIS

\vspace{0.2in}
\noindent
{\bf Workshop Goals:} learning; sharing CAASD reuse initiative results; advocating
the importance of standards for implementing interoperable libraries.

\vspace{0.2in}
\noindent
{\bf Working Groups:} tools and environments, education, reuse management,
organization and economics.

\end{abstract}

\newpage

\section{Background}

In November 1992 CAASD started an initiative to support and promote software
and information reuse within the center.
The CAASD Resource Discovery System is a network information discovery and
retrieval system built from Internet resource discovery tools and implemented
as a client-server computing model.  The system supports an asset library that
is implemented across distributed, heterogeneous computer platforms.
Client software is available on
a wide variety of computer platforms, including VT220s,
IBM PCs, Macintoshes, NeXT workstations, UNIX workstations, and X Window
terminals.  Server software is available for UNIX platforms.  Client-server
communication occurs over a network using TCP/IP.  The major Internet
resource discovery tools used in implementing the CAASD Resource Discovery
System are the Internet Gopher and Wide Area Information Servers (WAIS).
Descriptions of these tools and how they are used within 
the CAASD Resource Discovery System are
presented below.  The CAASD Resource
Discovery System has been available for on-line access since January 1993,
and has since received wide support at all levels in the corporation.

\section{Position}

Implementation
of an on-line asset library was viewed as a crucial step in
institutionalizing reuse within CAASD.  The
library mechanism had to be low cost, easy to set up and maintain, accessible
from the wide variety of computer platforms used by CAASD staff, and it had to meet the
requirements for an asset library mechanism.  Specifically, the asset library
had to allow for the automated search and retrieval of on-line information
in the form of text documents, images,
software, and pointers to sources of more information (meta-assets)
with minimal barriers between CAASD staff and the desired information.

The CAASD Reuse Team informally reviewed a number of asset library mechanisms.
None fit the set of candidate requirements.
The search was expanded.  The two main tools that were
evaluated and eventually used to build the CAASD asset library were the Internet
Gopher and Wide Area Information Servers (WAIS).
Given the recent advances in network information
discovery and retrieval technology, this class of tools seemed to lend
themselves to the solution of the problem.  

The Internet Gopher client/server provides a distributed information delivery
system around which a campus-wide information system (CWIS) can be readily
constructed.  While providing a delivery vehicle for local information,
Gopher also facilitates access to other Gopher and information servers throughout the
world.  \cite{ugt93}

WAIS is a networked information retrieval system that uses TCP/IP to connect
client applications to information servers.  Client 
applications request documents using user-supplied keywords and are able to
retrieve text or multimedia documents stored on the servers.  Servers search the full text
index for the documents and return a list of documents containing the keywords.
The client may then request the server to send a copy of any of the documents
found.  \cite{edguer92}

Gopher allows a user to browse for assets using a menu structure.  If a user wants to
access an item, Gopher will ``go fer'' it and, if possible, ``show'' it to the user.
Different Gopher clients have varying levels of capability with respect to 
``showing'' assets to the user.  All clients can display ASCII text documents.
Other document types which the Gopher protocol defines, and which may or may not be
supported by the specific client software for a computer platform, are sounds,
bit-mapped images, and multimedia documents.  If desired, the user may save the
document on the local disk drive, print the document on a local printer, or mail the
document to an email address.  Gopher can connect to other asset library systems
via the Gopher protocol, TELNET protocol (VT100 or TN3270 emulation), or
anonymous ftp.  Gopher also has interfaces to several information servers,
including Archie servers, CSO name servers (a class of electronic phone books),
and WAIS servers.  Archie is a system which allows searching indexes of
files available on anonymous ftp servers on the Internet \cite{krol92}.
CSO name servers allow users to access certain electronic phone books.  The
Gopher-WAIS interface allows the user to specify keywords to be used for a WAIS
search.  The results of the WAIS search are presented to the Gopher user as a
custom directory.  Items in the directory are assets which match the search
criteria.  In addition, WAIS uses a complex scoring algorithm for the assets
and presents the assets in sorted order, based upon the score of each asset.
This feature saves the user effort by automating the process of determining
which assets are most relevant, based on the user's search criteria.

The implementation of the CAASD Resource Discovery System consists of an
Internet Gopher server and a WAIS server running on a UNIX workstation.  Gopher
client software is available for UNIX workstations (X Window and character
based), Macintoshes, IBM PCs (DOS, Windows, and OS/2), and NeXT workstations.
Dumb terminals (for example, VT220s) may access the system by logging into a
special account and running a ``secure mode'', character-based Gopher client.
The CAASD Resource Discovery System has links to other Internet Gopher servers
maintained within MITRE, telnet links to the MITRE
on-line library catalogs, and links to anonymous ftp sites within MITRE.

The CAASD Resource Discovery System acts as a library mechanism for many
different types of assets
available for reuse by CAASD staff.  Asset types include technical reports,
letters, memos, briefings, meeting minutes, numerous databases, and software.
All of these asset types are searched, browsed, and retrieved using the common
mechanisms provided by the CAASD Resource Discovery System.  

A number of tasks have been accomplished to assist CAASD staff to utilize the
CAASD Resource Discovery System for the purpose of software reuse.  Software
description templates have been designed and distributed to CAASD staff.
These templates are used to capture information about software developed within
MITRE as well as information about software that was developed externally from
MITRE, but used within MITRE.  When the templates are filled in, these software
descriptions are collected, indexed, and made available through the CAASD
Resource Discovery System.  In addition, catalogs and information about
external software repositories, such as ASSET, AdaNET, and the NETLIB server
at research.att.com, have been reformatted, indexed, and made available through
the CAASD Resource Discovery System.  Both of these efforts provide a means for
searching through collections of descriptions of software assets available for
reuse to CAASD staff.  The software descriptions also provide information on
how to retrieve the software assets.  Finally, using the anonymous ftp facility
available within the CAASD Resource Discovery System, a large number of
software assets have been made available for direct retrieval by CAASD staff.

The CAASD Reuse Team is currently evaluating the use of enhancements to both
Gopher and WAIS as well as the use of World-Wide Web (WWW) technology.  Gopher
enhancements include serving documents in multiple types (for example, 
Microsoft Word, PostScript, and ASCII text).  WAIS enhancements include
the use of boolean operators, partial keywords, and literal phrases in
WAIS index searches.  WWW technology merges hypertext and network
information discovery and retrieval technologies in a very powerful paradigm.

All of the technology and software used to build the CAASD Resource Discovery
System is freely available from the Internet community.  Many information
resources related to these technologies are also available in the form of
network news groups and mailing lists.  For more information, please
consult the following sources.

\begin{description}
\item[{\bf The Internet Gopher.}]
Software is available via anonymous ftp to {\em boombox.micro.umn.edu} in
directory {\em /pub/gopher}.

Network news is discussed in {\em comp.infosystems.gopher}.

\item[{\bf WAIS.}]
Software is available via anonymous ftp to {\em ftp.cnidr.org} in
directory {\em /pub/NIDR.tools}.

Network news is discussed in {\em comp.infosystems.wais}.

\item[{\bf WWW.}]
Software is available via anonymous ftp to {\em ftp.ncsa.uiuc.edu} in
directory {\em /Mosaic}.

Network news is discussed in {\em comp.infosystems.www}.

\end{description}

\section{Comparison}

An asset library mechanism must make available a set of services for both the
library staff and the users of the library.  Both the North Atlantic
Treaty Organization (NATO) and the United States (U.S.) Department of Defense (DoD)
have put together documents specifying the recommended services to be provided
by asset library mechanisms.  This section presents the recommended services
and discusses how the CAASD Resource Discovery System performs these services.

\subsection{NATO}

NATO has issued a three volume set of standards to address the issue of
software reuse.

{\em Volume 1 - The Standard for the Development of Reusable Software
Components} is designed to provide guidance in the creation of software
products with maximum potential for software reuse.

{\em Volume 2 - The Standard for Management of a Reusable Software Component
(RSC) Library} provides guidance in the establishment and operation of a
NATO-controlled resource to support the reuse of software life-cycle products
in NATO contracts.  This volume also includes a section on library tool
management that discusses tool requirements of both the library staff and the
library user.  \cite{nato}

{\em Volume 3 - The Standard for Software Reuse Procedures} is designed to
provide guidance for software project teams who wish to practice reuse by
making significant use of reusable software components available in the NATO
Reuse Library.

\subsubsection{Library Staff Tool Requirements}

\begin{description}

\item[{\bf Support the cataloguing of RSCs.}]  WAIS provides a mechanism to
perform full-text indexing on asset descriptions and keyword searching on these
asset descriptions.  Each asset description exists as an individual file, and
these files may be bulk-loaded into the library system.  Gopher provides a
mechanism to allow a hierarchy of libraries to be created so that
domain-specific assets may be classified as such.

\item[{\bf Support the maintenance of the classification mechanism.}]  A
classification system is not formally used.  Instead, the full-text searching
mechanism of WAIS is utilized.

\item[{\bf Generate transaction and status reports.}]  Both Gopher and WAIS
maintain logs of accesses and queries.  These logs may be processed to
determine asset and user statistics.

\item[{\bf Support configuration management of the RSCs and of the classification vocabulary.}]
Gopher and WAIS do not directly address the issue of configuration management.
The Gopher server administrator is responsible for configuration management
of the RSCs.

\item[{\bf Support problem-report tracking.}]  Gopher and WAIS do not directly
address the issue of problem-report tracking.  Problem reports are tracked by
library staff.

\item[{\bf Support user and project tracking.}]  Gopher and WAIS do not
directly address the issue of user and project tracking, except by the logging
mechanism.  Tracking of users and projects is performed by library staff.

\item[{\bf Include adequate tool documentation.}]  Gopher allows for the
inclusion of help files that a user may browse in the same directory as the
search items and other tools.

\end{description}

\subsubsection{Library User Tool Requirements}

\begin{description}

\item[{\bf Provide reusers an effective RSC search and retrieval system.}]
Gopher and WAIS provide an excellent search and retrieval system accessible
from a wide variety of computer platforms.  The response to a keyword search
will be a custom directory showing asset titles which match the search
parameters.  If a title is selected, the full text of the asset description
will be made available to the user.

\item[{\bf Furnish documentation explaining the features and use of the tools.}]
As mentioned above, Gopher allows documentation to be provided on-line in help
files, where desired.  The library staff also provide paper copies of 
documentation to users.

\end{description}

\subsection{U.S. DoD}

Another document which identifies and categorizes a set of asset library
services is the {\em Asset Library Open Architecture Framework (ALOAF) -
Version 1.2}, developed under the Software Technology for Adaptable,
Reliable Systems (STARS) program \cite{aloaf92}.  Sponsored by the U.S.
Defense Advanced Research Projects Agency (DARPA), the STARS program is
supported by the military services, SEI, and MITRE, with the U.S. Air
Force as the executive contracting agent.  The STARS Asset Library
Framework (ALF) Service Model defines the categories of services that
individual library frameworks make available.

The ALF service categories and how each is addressed by the tools used in 
the CAASD Resource Discovery System are discussed below.

\begin{description}
\item[{\bf Session Services.}]  The Gopher protocol manages connections to the
asset library, provides other connection services through FTP and TELNET
protocols, and logs accesses to the asset library.

\item[{\bf Library Management Services.}]  Gopher provides services for
managing and manipulating an asset library.  The asset library maps into a
UNIX file hierarchy, with provisions for providing symbolic names to the files.

\item[{\bf Data Model Services.}]  Gopher and WAIS do not directly address data
model services.  Data models are managed and maintained by library staff.

\item[{\bf Asset description services.}]  Asset descriptions are managed and
manipulated outside of the Gopher and WAIS tools.

\item[{\bf Query Services.}]  Gopher and WAIS provide a keyword query service
on the full text of asset descriptions.  Results are returned and are sorted by asset
relevance as determined by the WAIS scoring algorithms.

\item[{\bf Asset Processing Services.}]  Asset processing varies on a 
case-by-case basis.  Some assets may be available through the anonymous ftp
mechanism available through Gopher.  Other assets may require contacting
the internal point of contact mentioned in the asset description.

\item[{\bf Metrics Services.}]  Gopher and WAIS provide logging mechanisms to
allow asset library administrators to collect statistics on library usage and
asset usage, as well as unsuccessful library queries.

\item[{\bf Access Control Services.}]  Gopher and WAIS provide access control
on a machine-by-machine basis.  User level authentication has been prototyped
but is not a part of the standard Gopher software distribution.
Currently, sensitive information is not made available through the CAASD
Resource Discovery System.

\end{description}

\bibliography{stockwell2}

\section{Biographies}

{\bf Timothy Stockwell} is a Member of the Technical Staff at The MITRE
Corporation, McLean, Virginia.  He is a lead researcher on information asset
reuse within the Center for Advanced Aviation System Development (CAASD) and
is also working with MITRE Corporate Informations Systems in exploring the use
of network information discovery and retrieval tools for searching and
accessing corporate databases.  Mr. Stockwell was previously involved with the design and
implementation of oceanic air traffic control prototypes and simulation models.
He received a B.S. in Computer and Systems Engineering from Rensselaer
Polytechnic Institute in 1988.

{\bf Mark Krause} is a Member of the Technical Staff at The MITRE Corporation,
McLean, Virginia.  Mr. Krause is a lead researcher specializing in network information
discovery and retrieval technologies and software and information reuse in support
of the CAASD Reuse Initiative and is also providing input at the corporate
level on information infrastructure re-engineering.  He was previously involved
in the design and implementation of en-route air traffic control systems.
Mr. Krause received a B.S. in Computer Science from George Mason University in 1990.

\end{document}



