1994 Working Papers
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Item Proceedings of the First New Zealand Formal Program Development Colloquium(Working Paper, 1994-11) Reeves, SteveThis volume gathers together papers presented at the first in what is planned to be a series of annual meetings which aim to bring together people within New Zealand who have an interest in the use of formal ideas to enhance program development. Throughout the World work is going on under the headings of "formal methods", "programming foundations", "formal software engineering". All these names are meant to suggest the use of soundly-based, broadly mathematical ideas for improving the current methods used to develop software. There is every reason for New Zealand to be engaged in this sort of research and, of growing importance, its application. Formal methods have had a large, and growing, influence on the software industry in Europe, and lately in the U.S.A. it is being seen as important. An article in September's "Scientific American" (leading with the Denver Airport debacle) gives an excellent overview of the way in which these ideas are seen as necessary for the future of the industry. Nearer to home and more immediate are current speculations about problems with the software running New Zealand's telephone system. The papers in this collection give some idea of the sorts of areas which people are working on in the expectation that other people will be encouraged to start work or continue current work in this area. We also want the fact that this works is going on to be made known to the New Zealand computer science community at large.Item Providing integrated support for multiple development notations(Working Paper, 1994-11) Grundy, John C.; Venable, John R.A new method for providing integrated support for multiple development notations (including analysis, design, and implementation) within Information Systems Engineering Environments (ISEEs) is described. This method supports both static integration of multiple notations and the implementation of dynamic support for them within an integrated ISEE. First, conceptual data models of different analysis and design notations are identified and modelled, which are then merged into an integrated conceptual data model. Second, mappings are derived from the integrated conceptual data model, which translate data changes in one notation to appropriate data changes in the other notations. Third, individual ISEEs for each notation are developed. Finally, the individual ISEEs are integrated via an integrated data dictionary based on the integrated conceptual data model and mappings. An environment supporting integrated tools for Object-Oriented Analysis and Extended Entity-Relationship diagrams is described, which has been built using this technique.Item The architecture of an optimistic CPU: the WarpEngine(Working Paper, 1994-09) Cleary, John G.; Pearson, Murray W.; Kinawi, HusamThe architecture for a shared memory CPU is described. The CPU allows for parallelism down to the level of single instructions and is tolerant of memory latency. All executable instructions and memory accesses are time stamped. The TimeWarp algorithm is used for managing synchronisation. This algorithm is optimistic and requires that all computations can be rolled back. The basic functions required for implementing the control and memory system used by TimeWarp are described. The memory model presented to the programmer is a single linear address space modified by a single thread of control. Thus, at the software level there is no need for explicit synchronising actions when accessing memory. The physical implementation, however, is multiple CPUs with their own caches and local memory with each CPU simultaneously executing multiple threads of control.Item Data transformation: a semantically-based approach to function discovery(Working Paper, 1994-08) Phan, Thong H.; Witten, Ian H.This paper presents the method of data transformation for discovering numeric functions from their examples. Based on the idea of transformations between functions, this method can be viewed as a semantic counterpart to the more common approach of formula construction used in most previous discovery systems. Advantages of the new method include a flexible implementation through the design of transformation rules, and a sound basis for rigorous mathematical analysis to characterize what can be discovered. The method has been implemented in a discovery system called "LINUS," which can identify a wide range of functions: rational functions, quadratic relations, and many transcendental functions, as well as those that can be transformed to rational functions by combinations of differentiation, logarithm and function inverse operations.Item Survival of the species vs survival of the individual(Working Paper, 1994-08) Barbour, Robert H.; Hopper, KeithThis paper examines the relationships between human and computing entities. It develops the biological ethical imperative towards survival into a study of the forms inherent in human beings and implied in computer systems. The theory of paradoxes is used to show that a computer system cannot in general make a self-referential decision. Based upon this philosophical analysis it is argued that human and machine forms of survival are fundamentally different. Further research into the consequences of this fundamental difference is needed to ensure the diversity necessary for human survival.