A Graphical Environment Supporting the Algebraic Specification of Abstract Data Types

Abstract Data Types (ADTs) are a powerful conceptual and practical device for building high-quality software because of the way they can describe objects whilst hiding the details of how they are represented within a computer. In order to implement ADTs correctly, it is first necessary to precisely describe their properties and behaviour, typically within a mathematical framework such as algebraic specification. These techniques are no longer merely research topics but are now tools used by software practitioners. Unfortunately, the high level of mathematical sophistication required to exploit these methods has made them unattractive to a large portion of their intended audience. This thesis investigates the use of computer graphics as a way of making the formal specification of ADTs more palatable. Computer graphics technology has recently been explored as a way of making computer programs more understandable by revealing aspects of their structure and run-time behaviour that are usually hidden in textual representations. These graphical techniques can also be used to create and edit programs. Although such visualisation techniques have been incorporated into tools supporting several phases of software development, a survey presented in this thesis of existing systems reveals that their application to supporting the formal specification of ADTs has so far been ignored. This thesis describes the development of a prototype tool (called VISAGE) for visualising and visually programming formally-specified ADTs. VISAGE uses a synchronised combination of textual and graphical views to illustrate the various facets of an ADT's structure and behaviour. The graphical views use both static and dynamic representations developed specifically for this domain. VISAGE's visual programming facility has powerful mechanisms for creating and manipulating entire structures (as well as their components) that make it at least comparable with textual methods. In recognition of the importance of examples as a way of illustrating abstract concepts, VISAGE provides a dedicated tool (called the PLAYPEN) that allows the creation of example data by the user. These data can then be transformed by the operations belonging to the ADT with the result shown by means of a dynamic, graphical display. An evaluation of VISAGE was conducted in order to detect any improvement in subjects' performance, confidence and understanding of ADT specifications. The subjects were asked to perform a set of simple specification tasks with some using VISAGE and the others using manual techniques to act as a control. An analysis of the results shows a distinct positive reaction from the VISAGE group that was completely absent in the control group thereby supporting the thesis that the algebraic specification of ADTs can be made more accessible and palatable though the use of computer graphic techniques

A structured approach to physically-based modeling for computer graphics

This thesis presents a framework for the design of physically-based computer graphics models. The framework includes a paradigm for the structure of physically-based models, techniques for "structured" mathematical modeling, and a specification of a computer program structure in which to implement the models. The framework is based on known principles and methodologies of structured programming and mathematical modeling. Because the framework emphasizes the structure and organization of models, we refer to it as "Structured Modeling." The Structured Modeling framework focuses on clarity and "correctness" of models, emphasizing explicit statement of assumptions, goals, and techniques. In particular, we partition physically-based models, separating them into conceptual and mathematical models, and posed problems. We control complexity of models by designing in a modular manner, piecing models together from smaller components. The framework places a particular emphasis on defining a complete formal statement of a model's mathematical equations, before attempting to simulate the model. To manage the complexity of these equations, we define a collection of mathematical constructs, notation, and terminology, that allow mathematical models to be created in a structured and modular manner. We construct a computer programming environment that directly supports the implementation of models designed using the above techniques. The environment is geared to a tool-oriented approach, in which models are built from an extensible collection of software objects, that correspond to elements and tasks of a "blackboard" design of models. A substantial portion of this thesis is devoted to developing a library of physically-based model "modules," including rigid-body kinematics, rigid-body dynamics, and dynamic constraints, all built with the Structured Modeling framework. These modules are intended to serve both as examples of the framework, and as potentially useful tools for the computer graphics community. Each module includes statements of goals and assumptions, explicit mathematical models and problem statements, and descriptions of software objects that support them. We illustrate the use of the library to build some sample models, and include discussion of various possible additions and extensions to the library. Structured Modeling is an experiment in modeling: an exploration of designing via strict adherence to a dogma of structure, modularity, and mathematical formality. It does not stress issues such as particular numerical simulation techniques or efficiency of computer execution time or memory usage, all of which are important practical considerations in modeling. However, at least so far as the work carried on in this thesis, Structured Modeling has proven to be a useful aid in the design and understanding of complex physically based models.</p

Playing Smart - Artificial Intelligence in Computer Games

Abstract: With this document we will present an overview of artificial intelligence in general and artificial intelligence in the context of its use in modern computer games in particular. To this end we will firstly provide an introduction to the terminology of artificial intelligence, followed by a brief history of this field of computer science and finally we will discuss the impact which this science has had on the development of computer games. This will be further illustrated by a number of case studies, looking at how artificially intelligent behaviour has been achieved in selected games

Multi-cultural visualization : how functional programming can enrich visualization (and vice versa)

The past two decades have seen visualization flourish as a research field in its own right, with advances on the computational challenges of faster algorithms, new techniques for datasets too large for in-core processing, and advances in understanding the perceptual and cognitive processes recruited by visualization systems, and through this, how to improve the representation of data. However, progress within visualization has sometimes proceeded in parallel with that in other branches of computer science, and there is a danger that when novel solutions ossify into `accepted practice' the field can easily overlook significant advances elsewhere in the community. In this paper we describe recent advances in the design and implementation of pure functional programming languages that, significantly, contain important insights into questions raised by the recent NIH/NSF report on Visualization Challenges. We argue and demonstrate that modern functional languages combine high-level mathematically-based specifications of visualization techniques, concise implementation of algorithms through fine-grained composition, support for writing correct programs through strong type checking, and a different kind of modularity inherent in the abstractive power of these languages. And to cap it off, we have initial evidence that in some cases functional implementations are faster than their imperative counterparts

On the Provision of a Comprehensive Computer Graphics Education in the Context of Computer Games

Position paper for the ACM SIGGRAPH/Eurographics Computer Graphics Education Workshop 200

Tools for modelling support and construction of optimization applications

We argue the case for an open systems approach towards modelling and application support. We discuss how the 'usability' and 'skills' analysis naturally leads to a viable strategy for integrating application construction with modelling tools and optimizers. The role of the implementation environment is also seen to be critical in that it is retained as a building block within the resulting system