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\title{Methodology Fusion: The Next Step}
 
\author{Donald J. Reifer\\
\\
Reifer Consultants, Inc.\\
P.O. Box 4046\\
Torrance, CA 90510\\
Tel:  (310) 373-8728\\
Email:  reiferd@source.asset.com\\
Fax:  (310) 375-9845\\
}
\date{}
\maketitle
\begin{abstract}

This paper discusses the need to consider solution space objects as we
model the problem space and develop our requirements models.  Several major
efforts are currently underway to develop domain and information engineering
methodologies which used different representations to model the problem space.

Most of these methods are being developed independent of one another.  As a
result, the impact of one on the other is not being addressed.  In addition,
their is a movement afoot to standardize data and exploit the use of reusable
software assets.  However, problem space modeling methods specifically avoid
being constrained by such solution space objects.

The author proposes a three step process for resolving the problem.
First, a high level domain and data model is developed independent of solution
space constrains for a product-line.  Next, the resulting models are used to
evaluate tradeoffs as product or project-related functional, performance,
interface and quality requirements are developed at a more detailed level.
Finally, solution space objects are considered as design requirements as the
requirements unfold and are specified.  The overall method fuses or integrates
several methods into one single overall solution approach.  It makes sure
solution space objects are considered as problem space specifications are
formulated at the individual project or product level.

To be successful, the process proposed must represent its underlying models 
using a consistent representation.  In addition, the criteria and rules which 
govern the acceptability of the interim products that result at each step of 
the process need to be made explicit along with the major tradeoffs that need
to be considered.  Finally, the methodology must be adapted to be compatible
with an object, functional or hybrid model and the translation from one to
another.
 
\vspace{0.2in}
\noindent
{\bf Keywords:} modeling, methodology integration, methodology fusion, 
standard data, reusable software assets, domain engineering, information 
engineering
 
\vspace{0.2in}
\noindent
{\bf Workshop Goals:} Broaden viewpoints, stimulate discussion and generate a 
few good ideas on how to deal with the challenge.
 
\vspace{0.2in}
\noindent
{\bf Working Groups:} Domain analysis/engineering; Reuse and OO methods, Method
fusion/integration
 
\end{abstract}
 

\newpage
\section{Background}

Mr. Reifer currently serves as Chief Architect for the DISA/CIM Software Reuse 
Program.  As part of his tasking, he is leading a joint Air Force, DARPA and 
DISA effort to provide DoD users with seamless access to a variety of reusable 
software assets via an interoperable network of heterogeneous reuse libraries.
He is also helping to develop strategy and is providing technical leadership 
for other aspects of the DISA/CIM Software Engineering and Reuse programs.

Mr. Reifer is also serving as the Reuse Advocate to CAE-Link Corporation on the
Space Station Simulator Project.  This project is building a facility to train 
Shuttle astronauts and mission controllers in Station operations.   His primary
focus on this project is on ensuring that reuse opportunities identified are 
fully exploited.
 

\section{Position - Fusion Method Needed}

Reuse is a hot topic in the worldwide software engineering community.  Many 
efforts are under way to improve both the state-of-the-art and 
state-of-the-practice because of the potential benefits.  Many of these efforts
are focused on exploiting domain specific architectures where the knowledge 
base of experience in the applications domain is used to create an
architectural framework for building systems~\cite{Braun92,Mettala92}.
However, the methods being used for domain engineering activities are not being
integrated with those being used to perform other critical engineering tasks 
pertinent to the architecture.  An integrated or combined methodology is needed
to provide those developing systems with guidance on what activities to do when
and how to know when they are done.

A method is defined in this context as consisting of~\cite{Kronlof93}:
\begin{itemize}\itemsep -3pt
  \item An underlying model - those classes of objects represented, manipulated
        and analyzed by the method.
  \item A consistent notation - the means used to represent the products of 
        the method.
  \item A process or ordered set of steps - the set of activities performed by
        the user of the methodology and their products.
  \item Guidance for applying the method - examples of products and the rules
        or criteria used to evaluate whether or not they are any good.
\end{itemize}

The purpose of this paper is to discuss a proposed integration or fusion
method from these four points of view.  This will be accomplished in the next
Section.  The concepts in this paper are still in the formative stages.  Plans
to take these concepts and refine them will be discussed in Section III.

A proposed methodology fusion concept which addresses the problem noted
above is shown in Figure 1. Problem space modeling techniques are ordered and 
put together using the process shown in Figure 2.  The approach taken is to 
consider solution space constrains as problem space objects are identified, 
fused together and evaluated using an iterative refinement process.  The 
ultimate product of this method is a set of requirements for a project or 
product which is bounded within a domain by a number of constraints.


\begin{figure}[ht]
\centering
\leavevmode\hbox{ \epsfbox{reifer-fig1.ps}}
\caption{Methodology Fusion Concept}
\label{f:overview}
\end{figure}


The object model seems suitable to serve as the underlying model for the 
proposed method because it permits classes to be specified and analyzed in a 
manner consistent with most of the popular domain and information engineering 
approaches.  An object model is powerful enough to permit the constraints being
placed on problem space representations by solution space objects to be traded
off and fully addressed.

A hybrid object-oriented notation seems appropriate because none of those 
analyzed seem to have the power to express the structure, associations and 
behavior of systems modeled using the fusion of techniques.  Most of the 
weaknesses observed to date have been in the area of performance.  To solve 
this problem, elements of Rumbaugh~\cite{Rumbaugh91} and Booch~\cite{Booch91}
could be coupled with specialized notations based upon my experience on the 
Space Station Simulator project~\cite{Wessale92}.

As illustrated in Figure 2, the process advanced is one of constrained 
optimization.  First, a problem space model is developed free of constrains.  
Then, constrains are systematically added in step by step so that tradeoffs 
can be made and the resulting model optimized.  The key concept to realize is 
that problem space models cannot be unconstrained when reusable assets and 
domain-specific architectures are being considered.  Design requirements need 
to be specified to bound the problem space so that it can be easily mapped
to solution space realizations.


\begin{figure} [ht]
\centering
\leavevmode\hbox{ \epsfbox{reifer-fig2.ps}}
\caption{Modified Analysis Process}
\label{f:process}
\end{figure}


Pilot programs will be used once the fusion method is specified to provide 
examples and develop the rules which will govern what to do when.  This 
``do-a-little, learn-a-lot'' philosophy has been used very effectively by  
many research programs to provide practical guidance to those actually trying 
to do the work.

Most of what has been proposed is nothing more than a paper tiger.  The problem
has been identified and an approach advanced to attack it.  Within the next few
months, we will mount a coordinated effort to put the method on paper.

Once specified, we will try it on one or more pilots to refine it based upon
operational feedback.  Examples will be developed along with rules.  Assuming
things work out, a fusion method handbook and training courses will be produced
and the methodology will be transitioned into use via a defined and disciplined
technology transfer process.

My purpose for discussing the proposed fusion method at the workshop is to get 
feedback.  I am particularly interested in related work.


\section{Comparison}

No similar work other than that referenced is known when dealing with fusion 
of the techniques shown in Figure 1. 


\bibliography{reifer}


\section{Biography}
 
{\bf Mr. Donald J. Reifer} is an internationally recognized expert in the 
fields of software engineering and management, with over twenty-five years of
progressive experience in both industry and government.  He has successfully
managed major projects, served on source selections, wrote winning proposals 
and led project recovery teams.  While affiliated with TRW, Mr. Reifer was the
Deputy Program Manager for Global Positioning Satellite (GPS) verification and
validation projects.  As a Software Director with the Aerospace Corporation,  
Mr. Reifer managed over \$800 million in software contracts for the Space
Transportation System (Space Shuttle) Directorate.  As a Project Leader at
Hughes Aircraft, Mr. Reifer managed several major weapons system developments.
Currently as President of RCI, a software consulting firm, Mr. Reifer directs
efforts aimed at helping Fortune 500 firms (CAE-Link, Rockwell, Shell, TI,
Westinghouse, etc.) and government agencies (DISA, NASA, etc.) to effectively
manage large software projects, organizations and technology introduction. His
current focus is on introducing software engineering and reuse technology.

Mr. Reifer is author of over 100 papers and several books on software 
engineering and management topics.  He is also the author of the popular  
ASSET-R size and SoftCost-Ada cost estimation models.  Mr. Reifer holds a 
B.S. in Electrical Engineering from Newark College of Engineering (NCE), an 
M.S. in Operations Research from the University of Southern California (USC) 
and the Certificate in Business Management from the University of California 
at Los Angeles (UCLA).  He is an ACM national lecturer and a past member of the
Board of Directors of the Ada Software Alliance.  His many honors include being
listed in Who's Who in the West, the NASA Distinguished Service Medal and the 
Hughes Aircraft Company Masters Fellowship.
 
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