Abstracts

Information Conundrum: Semantics... with a Payoff!

Jacek Kryt
Retired from Ryerson Polytechnic University. Toronto, Canada. res.: address: 21 Heathcote Avenue, Willowdale ON, M2L 1Y6, Canada;
jkryt@acs.ryerson.ca

The sorry state of business information systems is no longer a secret. Since 1968 we have had a computer science curriculum which is supposed to provide us with properly trained graduates to handle the problems related to this new technology. But there is criticism of those graduates voiced from various quarters. They have been very helpful developing this new technology, but they have failed to satisfy the needs of those who in search for information expected to benefit from the flow of data facilitated by computers. This prompts the question: what is this information anyway? Computer scientists assert that information is just data processed by computers. I will show that this view is unacceptable as it causes considerable harm to information systems now, and is likely to have a negative impact on the information society. We need a clear understanding of the term "information" the most fundamental term for the Information Age.(pp. 305-319)

Keywords: computer science, curriculum, data, end user, information, information highway, information systems, requirements, systems failures

Margot Postema, and Heinz W. Schmidt
School of Computer Science & Software Engineering, Monash University, 900 Dandenong Road, Caulfield East, VIC 3145, Australia;
margot@csse.monash.edu.au hws@csse.monash.edu.au

Extremely large software systems which have been developed and maintained by many different people are termed legacy systems. These legacy systems were traditionally developed using methods such as structured analysis and design, or even individual programming techniques and styles. Over time, maintenance has changed the original program structure and specifications. However, usually the specifications have not been maintained, and the current design and program understanding is lost. Maintenance of these systems becomes so costly, that they become candidate for reengineering. Reverse engineering of legacy systems aims at discovering design and specification of existing software program s. The recovered designs are then forward engineered to improved systems. This difficult task can be assisted by CASE tools, but still requires human expertise and domain knowledge. With a technology shift from structured to object-oriented software construction, an additional problem arises i.e. transforming the structured legacy system to an object-oriented system. We outline the current state of CASE tools, followed by research directions. Further, we indicate that a two staged approach may be advantageous, where self-contained subsystems can be abstracted for design recovery and object discovery.

Keywords:reverse engineering, legacy systems, transformation, abstraction

Floating-Point Arithmetic And The IEEE-754 Standard, I: Number-System Design

Amos R. Omondi
School of Informatics and Engineering, Flinders University, Bedford Park, SA 5042, Australia;

For many years almost every computer manufacturer had its own system for floating-point  computation, a situation that made software portability a difficult task with different machine architectures and implementations.  Moreover, not all of these systems were devised to facilitate error diagnosis or arithmetic with minimal errors.  The situation changed considerably with IEEE's introduction of a standard system (IEEE-754) that has now been adopted by almost all computer manufacturers and which solves most of the problem associated with previous floating-point systems.  Nevertheless, the rationale for the decisions made in formulation of the standard are not always well-understood. The objective of this paper is to discuss the issues involved in the design of a floating-point system and, in particular,  to explain and justify those made in the IEEE standard.  A companion paper deals with implementation issues. (pp. 413-429)

Keywords:computer arithmetic, floating-point, IEEE-754 standard

Prithwish Kangsabanik, R. Mall and A.K. Majumdar
Dept. of Computer Science and Engg. I.I.T Kharagpur, India;
prith@cse.iitkgp.ernet.in rajib@cse.iitkgp.ernet.in, akmj@cse.iitkgp.ernet.in

In this paper, we survey some of the recent developments in application modeling and concurrency control in Active DBMS (ADBMS). We first review the evolution of Active DBMS and different application areas of ADBMSs. Application modeling techniques for ADBMS applications have been surveyed after that. Then we discuss about the execution modeling and concurrency control in active DBMS -- which is one of the most challenging areas in active database research. Several important active database research projects are also reviewed with mention of their contributions and current research directions pointed out by these projects.

Keywords:  Active database, Concurrency control, Object oriented systems