Doris L. Carver

Identification of data cohesive subsystems using data mining techniques

The activity of reengineering and maintaining large legacy systems involves the use of design recovery techniques to produce abstractions that facilitate the understanding of the system. We present an approach to design recovery based on data mining. This approach derives from the observation that data mining can discover unsuspected non-trivial relationships among elements in large databases. This observation suggests that data mining can be used to elicit new knowledge about the design of a subject system and that it can be applied to large legacy systems. We describe the ISA methodology which uses data mining to identify data cohesive subsystems. We were able to decompose COBOL systems into subsystems by using this approach. Our experience shows that data mining can identify data cohesive subsystems without any previous knowledge of the subject system. Furthermore, data mining can produce meaningful results regardless of system size making this approach especially appropriate to the analysis of large undocumented systems.

Analyzing the impact of changing requirements

Determining the impact of requirement changes on software development is critical to project management. We present an impact analysis method to evaluate requirement changes for software development projects that is based on requirements traceability. By using attributes of the work products and traces, we create classes of requirement changes prioritized according to the potential impact. We present a case study that shows a favorable comparison between the actual impact and the predicted impact. Finally, we discuss the expansion of the method.

Shortchanging the future of information technology: the untapped resource

Building on ideas from a virtual workshop and additional input from the scientific community, the CISE Directorate at the National Science Foundation established the Information Technology Workforce Program (ITWF) in March 2000 to support a broad set of scientific research studies focused on the under-representation of women and minorities in the information technology workforce. In this paper, we explore various approaches that the funded researchers are taking to address the problem of women in information technology. We begin with a brief history of the ITWF, and then focus on some of the research projects in terms of their goals, approaches, and expected outcomes.

A visual representation model for software subsystem decomposition

Decomposing a software system into subsystems is an important activity in the reverse engineering and maintenance domains. One approach to subsystem decomposition is based on data mining techniques. The ISA (Identification of Subsystems based on Associations) methodology decomposes a software system into subsystems by mining association rules from a database representation of the target system. This paper defines a visual representation model (RM) to graphically present the information produced by ISA. RM provides a graphical view of the recovered subsystem decomposition, the subsystems components, and the relationships among the subsystems. RM includes notation to represent hierarchies of file implications and hierarchies of subsystems. Results of applying RM to represent the subsystem decomposition of a COBOL system are discussed.

Reengineering legacy systems for distributed environments

In the last decade, we have seen an increasing use of both the object-oriented paradigm and distributed systems. As a result, there is increasing interest in migrating and reengineering legacy systems to these new hardware technologies and software development paradigms. We define a reengineering environment that assists with the migration of legacy systems to distributed object environments. The reengineering environment includes the methodology and an integrated set of tools that support the implementation of the methodology. The methodology consists of multiple phases. First, we use reverse engineering techniques for program comprehension and design recovery. We then decompose the system into a hierarchy of subsystems by defining relationships between the entities of the underlying paradigm of the legacy system. The decomposition is driven by data mining, software metrics, and clustering techniques. Next, if the underlying paradigm of the legacy system is not object-based, we perform object-based adaptations on the subsystems. We then create components by wrapping objects and defining an interface. Finally, we allocate components to different sites by specifying the requirements of the system and characteristics of the network as an integer-programming model that minimizes the remote communication. We use middleware technologies for the implementation of the distributed object system.

A graph-based object identification process for procedural programs

We describe a reengineering process for transforming procedural systems into object-oriented systems. The method is based on the program representation model, which is restructured by merging together cohesive components of the system. We present the model restructuring technique and discuss how the restructured model can be used for object identification.

Creating object-oriented designs from legacy FORTRAN code

The majority of scientific and engineering software systems currently in use are on average 10 to 15 years old. They have undergone extensive maintenance and, therefore, suffer from such problems as inaccurate or missing documentation, poorly structured code, and low modular cohesion. Moreover, the mere age of such systems has prohibited their realization of such recent innovations as object orientation. This paper addresses these concerns in the context of reverse engineering. It discusses the development of a method to identify objects in legacy systems, specifically those coded in the imperative language, FORTRAN-77. Algorithms that use a greedy approach to object extraction are presented. Viewing the subroutine as the unit of functionality, the attributes of candidate objects are extracted from two areas: parameters and global variables. Because FORTRAN-77 uses the COMMON block as the mechanism for realizing global variables, additional algorithms are presented to handle the resulting concerns. Using a modification of the program slicing concept introduced by Weiser in 1984, methods are defined for each set of attributes. The combination of the extracted attributes and methods forms the set of candidate objects. Throughout the paper, an example is used to illustrate the methodology.

Evolutionary migration of legacy systems to an object-based distributed environment

There is an increasing interest in migrating legacy systems to new hardware platforms and to new software development paradigms. High maintenance costs and lack of documentation are among the challenges facing software engineers who wish to migrate such systems. The increasing emphasis on distributed systems and on the object-oriented paradigm suggests that object-oriented, component-based, distributed systems will represent a significant portion of the next generation of software systems. We present a semiautomatic, evolutionary migration methodology for legacy systems which produces an object-based distributed system. We use ISA which is a design recovery and subsystem classification technique that produces a data-cohesive hierarchical subsystem decomposition of the subject system. We adapt the subsystems to the object-oriented paradigm. We wrap and define interfaces of the subsystems in order to define components. Components are allocated to multiple sites. Finally, middleware technologies for distributed systems are used to implement the communication between components. The approach is suitable for the evolutionary migration of legacy systems since each component can be reengineered separately.

Experiences in translating Z designs to Haskell implementations

Z is a widely used, model‐oriented specification language. Haskell is a programming language that was recently developed to serve as a standard for non‐strict, purely functional languages. Although functional languages have proved to be excellent prototyping tools, Haskell was designed as a general purpose language which could be used when building large software systems.

Weaving ontologies to support digital forensic analysis

Numerous challenges currently face digital forensic analysis. Although a variety of techniques and tools exist to assist with the analysis of digital evidence, they inadequately address key problems. We consider the applicability and usefulness of weaving ontologies to address some of these problems. We introduce an ontological approach leading to future development of an automated digital forensic analysis tool.