A real time, system independent, secure, Internet based auctioning system.

Thesis (M.Sc.)-University of Natal,Durban, 2000.This thesis outlines the creation of a secure, real time, system independent, Internet based auctioning application. The system has been developed to meet the needs of today's stringent reqUirements on secure Internet based applications. To attain this goal, the latest cryptographic algorithms and development platforms have been used. The result is a JAVA based server and client auctioning application. The client application is designed to run In any common web browser, and the server to execute on any JAVA enabled operating system with a web server and Internet connection. The real time system uses a relatively secure hybrid cryptosystem for communication. This involves the use of RSA for secure key exchange, and RC6 and MARS for secure communication

Extracting proofs from documents

Often, theorem checkers like PVS are used to check an existing proof, which is part of some document. Since there is a large difference between the notations used in the documents and the notations used in the theorem checkers, it is usually a laborious task to convert an existing proof into a format which can be checked by a machine. In the system that we propose, the author is assisted in the process of converting an existing proof into the PVS language and having it checked by PVS. 1 Introduction The now-classic ALGOL 60 report [5] recognized three different levels of language: a reference language, a publication language and several hardware representations, whereby the publication language was intended to admit variations on the reference language and was to be used for stating and communicating processes. The importance of publication language ---often referred to nowadays as "pseudo-code"--- is difficult to exaggerate since a publication language is the most effective way..

Diagnosing runtime violations of security and dependability properties

Monitoring the preservation of security and dependability (S&D) properties of complex software systems is widely accepted as a necessity. Basic monitoring can detect violations but does not always provide sufficient information for deciding what the appropriate response to a violation is. Such decisions often require additional diagnostic information that explains why a violation has occurred and can, therefore, indicate what would be an appropriate response action to it. In this thesis, we describe a diagnostic procedure for generating explanations of violations of S&D properties developed as extension of a runtime monitoring framewoek, called EVEREST. The procedure is based on a combination of abductive and evidential reasoning about violations of S&D properties which are expressed in Event Calculus

Database-driven hydraulic simulation of canal irrigation networks using object-oriented high-resolution methods

Canal hydraulic models can be used to understand the hydraulic behaviour of large and complex irrigation networks at low cost. A number of computational hydraulic models were developed and tested in the early 1970s and late 80s. Most were developed using finite difference schemes and procedural programming languages. In spite of the importance of these models, little progress was made on improving the numerical algorithms behind them. Software development efforts were focused more on developing the user interface rather than the core algorithm. This research develops a database-driven, object-oriented hydraulic simulation model for canal irrigation networks using modern high-resolution shock capturing techniques that are capable of handling variety of flow situations which includes trans-critical flow, shock propagation, flows through gated structures and channel networks. The technology platforms were carefully selected by taking into account a multi-user support and possible migration of the new software to a web-based one which integrates a Java-based object-oriented model with a relational database management system that is used to store network configuration and simulation parameters. The developed software is tested using a benchmark test suite formulated jointly by the Department for Environment, Food and Rural Affairs (DEFRA) and the Environment Agency (EA). A total of eight tests (seven of them adapted from the DEFRAjEA benchmark suite) were run and results compiled. The developed software has outperformed ISIS, REC-RAS and MIKE 11 in three of the benchmark tests and equally well for the other four. The outcome of this research is therefore a new category in hydraulic simulation software that uses modern shock-capturing methods fully integrated with a configurational relational database that has been fully evaluated and tested.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

On the definition of non-player character behaviour for real-time simulated virtual environments.

Computer games with complex virtual worlds, which are populated by artificial characters and creatures, are the most visible application of artificial intelligence techniques. In recent years game development has been fuelled by dramatic advances in computer graphics hardware which have led to a rise in the quality of real-time computer graphics and increased realism in computer games. As a result of these developments video games are gaining acceptance and cultural significance as a form of art and popular culture. An important factor for the attainment of realism in games is the artificially intelligent behaviour displayed by the virtual entities that populate the games' virtual worlds. It is our firm belief that to further improve the behaviour of virtual entities, game AI development will have to mirror the advances achieved in game graphics. A major contributing factor for these advancements has been the advent of programmable shaders for real-time graphics, which in turn has been significantly simplified by the introduction of higher level programming languages for the creation of shaders. This has demonstrated that a good system can be vastly improved by the addition of a programming language. This thesis presents a similar (syntactic) approach to the definition of the behaviour of virtual entities in computer games. We introduce the term behaviour definition language (BDL), describing a programming language for the definition of game entity behaviour. We specify the requirements for this type of programming language, which are applied to the development and implementation of several behaviour definition languages, culminating in the design of a new game-genre independent behaviour definition (scripting) language. This extension programming language includes several game AI techniques within a single unified system, allowing the use of different methods of behaviour definition. A subset of the language (itself a BDL) was implemented as a proof of concept of this design, providing a framework for the syntactic definition of the behaviour of virtual entities in computer games