Future Directions in CASE Repositories

Today, components and Component Based Development (CBD) is seen as one of the important events in the evolution of information technology. Components and CBD offer the promise of a software marketplace where components may be built, bought, or sold in a manner similar to components in other industries. In the light of the ongoing developments, in the manner and art of developing software systems, it is important to consider how the Computer Aided Systems Engineering (CASE) environment that supports building these systems can be produced on a CBD approach. In spite of the fact that CASE environments have been around since the ’70s, there are still many problems with these environments. Among the problems of CASE environments are the lack of conceptual models to help understand the technology, the poor state of user requirements specification, inflexible method, support and complicated integration facilities, which contribute to the dissatisfaction in CASE users. During the ’90s there has been a growing need to provide a more formal basis to the art of software development and maintenance through standardized process and product models. The importance of CAME (Computer Aided Method Engineering) in CASE led to the development of CASE shells, MetaCASE tools, or customizable CASE environments that were intended to overcome the inflexibility of method support. The declining cost of computing technology and its increasing functionality, specifically in graphic user interfaces, has contributed to the present re-invention of CASE environments. CASE research in the last decade has addressed issues such as method integration, multiple user support, multiple representation paradigms, method modifiability and evolution, and information retrieval and computation facilities. Considerable progress has been made by isolating particular issues and providing a comprehensive solution with certain trade-off on limited flexibility. The requirement of a fully Component Based architecture for CASE environments has been not examined properly. The combination of requirements of flexibility in terms of support for arbitrary modeling techniques, and evolution of the development environment to ever-changing functionality and applications never the less needs a flexible environment architectures. Therefore, the theory formulation and development of a prototype for designing a next generation of CASE environments is addressed in this book. A CAME environment is considered as a component of a CASE environment. A comprehensive solution is sought to the environment problem by paying attention to a conceptual model of such an environment that has been designed to avoid the confusion around integration issues, and to meet the specification of user requirements concerning a component-based architecture. A CAME environment provides a fully flexible environment for method specification and integration, and can be used for information systems design activities. A large part of this book reports how this theory leads to the designing of the architecture of such an environment. This final chapter contains a review of the theory and an assessment of the extent to which its applicability is upheld.

Information Systems Development and the Need for Computer Aided Method Engineering

The business issues of today are global in nature, for instance, organizational objectives may be as varied as increasing profits, obtaining faster product life cycles, or increasing the competition at a global level. To get more value out of a business, people tend to re-engineer the business process. Development of information systems today is mostly the process of bringing improvements to the existing system, as part of a large business change initiative, and systems development efforts that do not address these problems tend to be incomplete or inefficient. As a result, the introduction of various applications and architectures is becoming increasingly common. New and different technologies such as telecommunication, artificial intelligence, image processing, multimedia, object orientation, as well as various applications such as batch or on-line transaction processing, process control, decision support, and work flow support are increasingly being introduced to improve the performance of business processes. Information systems development is changing, and the types of systems being built are much more varied and complex.

Computer Aided Method Engineering

The relationship between information systems development methods, organizational information systems engineering requirements, and the advantage of flexible automated support environments is presented. CASE technology is presented as a possible solution to provide flexible automated support. In this chapter the major topic is a conceptual model to specify the functionality of a support environment. First a review of a number of basic concepts and approaches for deriving models for CASE environments are given. An informal description of service component concepts used to derive a generic framework is presented. Further, a configuration of service components, to support Computer Aided Method Engineering (CAME), is outlined.

Supporting Dynamic Essential Modeling of Organizations

Today’s information systems design and development activities demand flexibility from supporting arbitrary modeling approaches. Improvements to the business process as a result of the introduction of new technologies and applications requires the adaptation of modeling approaches to accommodate the changing demands of analysis and design. Therefore, this chapter focuses on supporting the new and changing demands in analysis and design of information systems. An understanding of the business process is important in order to design a proper information architecture for the problem at hand, therefore, the modeling of the business process of an organization is the focus of this chapter, to improve the understanding of the problem situation before designing and developing an information system. The problem of analyzing a hotel reservation and reception activities according to the DEMO modeling approach (Dietz, 1996) is presented in this chapter.

Supporting Object Oriented Modeling Techniques

This chapter focuses on exploring the capability of the CAME environment, to support a problem area that requires a design approach that uses the modeling techniques of an object oriented method. The problem presented lies in the design and development of a computerized automobile map system using the modeling techniques prescribed by the OMT method (Rumbaugh et al., 1990). As this problem area requires an object modeling technique, the need to advocate UML was not necessary. The case study is concerned with the introduction of computerized display systems in automobiles, and one of the potential applications for these systems is automated map display. The map system should provide access to a collection of maps for a region. Within this region, the maps should show cities, towns, and the routes between them. The maps should also display restaurants, hotels, and other points of interest to travelers. Within large cities, enough roads will be shown to give an efficient route between any two points. The system should automate as much of the access and displaying of the maps as possible. Simple function buttons will be provided to allow the user to zoom in or out, or pan across the map in any direction. The system should control display clutter automatically by showing only the most important features at the selected zoom level. In the default mode, a region surrounding the cars’ current position will be shown, and the display should scroll automatically to reveal new map features as the car moves. The automobile’s position will be determined using a global positioning device that computes position based on satellite signals. The above outlines the functionality required from a computerized automobile map system.

The Formalization of CAME Architecture

An informal description of a CAME framework based on the service object concept is presented in Chapter 3. Now the focus will be on the representational formalism of a CAME environment that can be used to implement a CAME environment to provide flexible modeling support for information systems design activities. A conceptual framework for a CAME environment using building blocks specification or a meta-meta model will be the main concentration in this chapter. The modeling techniques that are used to design information architectures of modeling techniques are popularly known as meta modeling techniques. To formalize the informal architectural building blocks of a CAME environment given in Chapter 3, one needs a uniform meta modeling technique capable of specifying the CAME service object primitives. Many examples of such techniques can be found in the literature; therefore, first the arguments for using PSM, task structure and LISA-D (Hofstede, 1993) base modeling technique as the meta modeling technique are stated. The architectural building blocks of the meta-meta model, which represent the service object based theory for CAME environments that can be used to provide a flexible modeling support for information systems design activities are presented in the remainder of the chapter. In this meta meta model the transaction service is not formally specified in order to keep the presentation limited to the method engineering needs. A formal and descriptive specifications of all these basic CAME services are available in Dahanayake (1997). The notational convention of PSM modeling technique is given in Appendix A.

The CAME Environment's Basic Component Services

In Chapter 2 an object model-based concept, the service object for the specification of basic services of a CAME environment, is given. The focus of this chapter is to identify the composition of such an environment. The basic service objects and relevant service object primitives of a service-based model of a CAME environment is presented in this chapter by mapping the services and primitives to an example problem domain. This example problem is used to formulate a generic architectural representation for a CAME service description of an information modeling support environment. Such a representation should be capable of providing a flexible and extendable mechanism for information systems design processes. An informal description of the basic CAME service framework is presented in the remainder of the chapter.

Architecture and Implementation Issues

Historically the focus is on the theory of how problem-specific systems design tools can be supported by a Computer Aided Method Engineering (CAME) environment based on service object representation. To arrive at an implementation model, the conceptual model of the service object representation must be formalized. This theory is feasible when there is adequate computer support. Many researchers have emphasized strongly that requirement specification languages should have a rigorous formal basis; however, this need for formality has not been generally acknowledged in the field of information systems development. Most organizations and research groups tend to define their own methods using techniques advocated within such methods that often have no formal foundation. Discussions of modeling techniques are based on numerous examples, mostly using diagrams and notational conventions, to provide a popular style for the definition of new concepts and their behavior. In a CAME environment however, which gives the freedom to specify a modeling technique from scratch, it is difficult to avoid deficiencies such as inconsistency, lack of structure, over specification, incompleteness, ambiguity, and redundancy without using a formal approach. In automated support a formal model is used to provide stable specifications for implementation. In fact, an implementation can be seen as another, enormously detailed formal description, usually in an imperative programming language. To implement this sophisticated automated support, formal specifications of the CAME service description with adequate formal reasoning were derived earlier.

Supporting Modeling Structured Analysis and Design

The first case study focuses on evaluating the capability of the CAME environment of supporting a problem area that requires a structured analysis and design method. The specific problem lies in the financial and administration sector of the example problem, Dutch flower auction (see Chapter 3). Financial administration is an activity that is required frequently within organizations, and the analysis, design, and development of such an information system are normally supported by a structured analysis and design method. This case investigates the modeling process and techniques required for a popular structured analysis and design method known as the YOURDON method. The financial and administration sector’s problem is used as the problem area of this case study based on the following considerations: a problem preferably of a general nature, meaning that development of similar information systems is common, is the object of investigation. The Dutch flower auction’s financial and administration sector’s problem is one of a typical data processing nature, and this is clearly a frequently occurring problem area in information systems development. The problem area has to be such that a structured analysis and design method would be adopted during information systems analysis and design. Otherwise it could not be considered to be information systems modeling support according to a structured analysis and design method. The YOURDON method (Yourdon, 1989) is particularly well known for its support of the problem area of data processing and real-time systems analysis and design. This means all clones of the YOURDON method described in literature include the real-time analysis and design. The selection of the YOURDON method to investigate this particular problem is based on the preference of students who worked with this particular example problem based on the course “Information Systems Analysis and Design Methodologies” at Delft University of Technology. The various versions of the YOURDON method give varying interpretations of its modeling techniques Data Flow Diagram (DFD), Entity Relationship Diagram (ERD), and State Transition Diagram (STD). The automated support must provide not only the required modeling techniques, but also the different variations of these techniques as required to deal with the problem area.