Computer Science

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Vector graphics to improve BLAST graphic representations
(2007) Jimenez, Rafael.
BLAST reports can be complicated. Viewing them graphically helps to understand them better, especially when the reports are long. At present "Web BLAST" and the stand-alone "wwwBLAST" versions, distributed by the NCBI, include graph- ical viewers for BLAST results. An alternative approach is "BLAST Graphic Viewer" developed by GMOD as part of the BioPerl library. It provides a more aesthetically pleasing and informative graphical visualization to represent BLAST results. All the strategies mentioned above are based on the use of bitmap graph- ics and dependent on JavaScript code embedded in HTML. We present Vector Graphic BLAST (VEGRA) a Python object orientated library based on BioPy- thon to yield graphical visualization of results from BLAST utilizing vector graph- ics. Graphics produced by VEGRA are better than bitmaps for illustration, more exible because they can be resized and stretched, require less memory, and their interactivity is more e ective as it is independent of tertiary technologies due to its integration into the graphic. In addition, the library facilitates a de nition of any layout for the di erent components of the graphic, as well as adjustment of size and colour properties. This dissertation studies previous alternatives and improves them by making use of vector graphics and thus allowing more e ective presentation of results. VEGRA is not just an improvement for BLAST visualiza- tion but a model that illustrates how other visualization tools could make use of vector graphics. VEGRA currently works with BLAST, nevertheless the library has been written to be extended to other visualization problems.
Component-based face recognition.
(2008) Dombeu, Jean Vincent Fonou.; Tapamo, Jules-Raymond.
Component-based automatic face recognition has been of interest to a growing number of researchers in the past fifteen years. However, the main challenge remains the automatic extraction of facial components for recognition in different face orientations without any human intervention; or any assumption on the location of these components. In this work, we investigate a solution to this problem. Facial components: eyes, nose, and mouth are firstly detected in different orientations of face. To ensure that the components detected are appropriate for recognition, the Support Vector Machine (SVM) classifer is applied to identify facial components that have been accurately detected. Thereafter, features are extracted from the correctly detected components by Gabor Filters and Zernike Moments combined. Gabor Filters are used to extract the texture characteristics of the eyes and Zernike Moments are applied to compute the shape characteristics of the nose and the mouth. The texture and the shape features are concatenated and normalized to build the final feature vector of the input face image. Experiments show that our feature extraction strategy is robust, it also provides a more compact representation of face images and achieves an average recognition rate of 95% in different face orientations.
Investigation of techniques for automatic polyphonic music transcription using wavelets.
(2009) McGuiness, John C.; Murrell, Hugh Crozier.
It has been said (although sadly I have no source) that music is one of the most useful yet useless phenomena known to mankind. Useless in that it has, apparently, no tangible or immediately practical function in our lives, but extremely useful in that it is a truly universal language between human beings, which transcends boundaries and allows us to express ourselves and experience emotions in rather profound ways. For the majority of us, music exists to be listened to, appreciated, admired (sometimes reviled) but generally as some sort of stimulus for our auditory senses. Some of us feel the need to produce music, perhaps simply for our own creative enjoyment, or maybe because we crave the power it lends us to be able to inspire feelings in others. For those of us who love to know “the reason why” or “how things work” and wish to discover the secrets of music, arguably the greatest of all the arts, there can surely be no doubt that a fascinating world of mathematics, harmony and beauty awaits us. Perhaps the reason why music is able to convey such strong emotions in us is because we are (for whatever strange evolutionary reason or purpose) designed to be innately pattern pursuing, sequence searching and harmony hungry creatures. Music, as we shall discover in this research, is chock-a-block full of the most incredible patterns, which are just waiting to be deciphered.
Computer assisted education : design, development and evaluation.
(2001) Murrell, Katherine Ann.; Meyerowitz, Jane Julia.
Educational institutions throughout the world are increasingly facing classes of educationally, culturally and linguistically diverse student groups. At the same time economic constraints require these institutions to expand their student base and they are therefore looking to distance education and continuing education modules to meet these challenges. Simultaneously rapid advances in desktop computing capabilities and Internet delivered information have revived interest in Computer Assisted Education (CAE). The University of Natal is no exception to these trends; schools, departments and individual members of staff are increasingly exploring the possibility of using the University's computer infrastructure to assist in delivering quality education, maintaining current standards, and addressing the multiple needs of the students. To investigate these issues a CAE program was developed for use in the Nelson R. Mandela School of Medicine to investigate how students would make use 'of the technology, and to report on the development and evaluation processes of such a development. In doing so various lessons could be learnt which could inform the further development of such software at the University. In order to support the development of the CAE program an extensive literature survey into current educational theory was conducted. Its objectives were to explore and understand all the factors affecting the development and use of computer based systems as an educational tool. Particular aspects considered were • the debate between constructivist and instructivist theory in their applicability to both the medium and the subject material. • instructional styles, and with them the learning styles, that could be used to support the educational goals of the diverse student population. • instructional design methodologies that are currently used as well as media production methodologies. The goal of this aspect of the research was to advise both the development of the case study and to gain a broader understanding of the methodology that could be used for other developments. Included in this phase of the research are methods and criteria for selection of authoring systems and interface design issues in a multi-cultural multi-lingual environment. • the review of different evaluation strategies in order to incorporate appropriate evaluation in the CAE case study. • the investigation of broader sociological and historical factors that may influence the way in which CAE can be used effectively in a South African context. The presumption was that students from historically disadvantaged backgrounds and those with English as a second language would be less willing to use technological interventions than those who were more likely to have had access to computers earlier in their education. The case study set out to investigate if this presumption was valid, and if so what elements of design and delivery could facilitate these students' usage of such systems. However, these presumptions were not validated by the case study, showing the exact opposite of expectations, with more historically disadvantaged students showing a willingness to use the module.
An investigation into the use of genetic programming for the induction of novice procedural programming solution algorithms in intelligent programming tutors.
(2004) Pillay, Nelishia.; Sartori-Angus, Alan G.
Intelligent programming tutors have proven to be an economically viable and effective means of assisting novice programmers overcome learning difficulties. However, the large-scale use of intelligent programming tutors has been impeded by the high developmental costs associated with building intelligent programming tutors. The research presented in this thesis forms part of a larger initiative aimed at reducing these costs by building a generic architecture for the development of intelligent programming tutors. One of the facilities that must be provided by the generic architecture is the automatic generation of solutions to programming problems. The study presented in the thesis examines the use of genetic programming as means of inducing solution algorithms to novice programming problems. The scope of the thesis is limited to novice procedural programming paradigm problems requiring the use of arithmetic, string manipulation, conditional, iterative and recursive programming structures. The methodology employed in the study is proof-by-demonstration. A genetic programming system for the induction of novice procedural solution algorithms was implemented and tested on randomly chosen novice procedural programming problems. The study has identified the standard and advanced genetic programming features needed for the successful generation of novice procedural solution algorithms. The outcomes of this study include the derivation of an internal representation language for representing procedural solution algorithms and a high-level programming problem specification format for describing procedural problems, in the generic architecture. One of the limitations of genetic programming is its susceptibility to converge prematurely to local optima and not find a solution in some cases. The study has identified fitness function biases against certain structural components that are needed to find a solution, as an additional cause of premature convergence in this domain. It presents an iterative structure-based algorithm as a solution to this problem. This thesis has contributed to both the fields of genetic programming and intelligent programming tutors. While genetic programming has been successfully implemented in various domains, it is usually applied to a single problem within that domain. In this study the genetic programming system must be capable of solving a number of different programming problems in different application domains. In addition to this, the study has also identified a means of overcoming premature convergence caused by fitness function biases in a genetic programming system for the induction of novice procedural programming algorithms. Furthermore, although a number of studies have addressed the student modelling and pedagogical aspects of intelligent programming tutors, none have examined the automatic generation of problem solutions as a means of reducing developmental costs. Finally, this study has contributed to the ongoing research being conducted by the artificial intelligence in education community, to test the effectiveness of using machine learning techniques in the development of different aspects of intelligent tutoring systems.
The application of the unified modelling language and soft systems metholdology for modelling the production process in an aluminium plant.
(2003) Sewchurran, Kosheek.; Warren, Peter R.
This research explores the combined use of soft systems methodology (SSM) and UML based business process modelling (BPM) techniques. These two techniques are integrated to provide a framework for the analysis and definition of suitable business process models. Such integration better supports developers following objectoriented (00) approaches than traditional business process modelling. The thesis describes the importance and difficulties in getting development proj ects aimed at the correct needs. We provide an overview of current business process modelling practices. From this it is argued that current practices show two major weaknesses. Firstly, the modelling language that is used is not a current standard amongst developers who now expect 00 and UML based approaches. Secondly, the techniques used do not emphasise analysis, often resulting in a lack of appreciation of the problem. In order to deal with these inadequacies, the thesis critically examines suitable techniques that can be used to analyse and model business processes to support the developer's requirements. The examination of SSM reveals that the technique does deal with the analysis limitations of current business process modelling techniques. SSM has been linked to information systems provision by previous researchers. Unfortunately the examination ofthese research attempts shows that the linking is conducted in an ad-hoc manner with no underlying theoretical basis or emphasis on business process modelling. We show how soft systems methodology techniques can be married with Eriksson and Penker (2000) UML business process modelling techniques following Mingers (2001) multi-methodology framework in a way that can over come these difficulties. This combined business analysis and modelling technique is applied to the production process in an aluminium rolling plant. Based on the experiences at one site, the integrated approach is able to deal with the complexities caused by multiple stakeholders, and is able to provide a UML representation of the required business process to guide developers.
Executive information systems usage : the impact of web-based technologies.
(2002) Averweg, Udo Richard Franz.; Petkov, Don.
Executive Information Systems (EIS) grew out ofthe information needs of top executives. The recent literature reports that EIS usage has spread throughout organisations. Web-based technologies are causing a revisit of existing IT implementation models, including those for EIS. These technologies include: Intranet, Internet, Extranet, e-Commerce: Business-to-Business (B2B), e-Comrnerce: Business-to-Consumer (B2C), Wireless Application Protocol (WAP) and other mobile technologies. The author conducts a field study of 31 well-established organisations in KwaZulu/Natal, South Africa, which have EIS experience. A validated survey instrument is administered to an EIS stakeholder in each organisation surveyed. This dissertation reports on (1) an investigation into previous research on IT adoption; (2) that there is little evidence to support that the theoretical usage aspects of the Technology Acceptance Model (TAM) are echoed in EIS implementations in KwaZulu/Natal; and (3) identifies and ranks Web-based technologies in order of their perceived impact on EIS currently and in the future. There is a positive impact level trend for all Web-based technologies on future EIS implementations. The results from this field study could be useful in formulating a set of management perspectives for organisations in South Africa wishing to embark on EIS implementation programs.
An interpretive study of software risk management perspectives.
(2002) Padayachee, Keshnee.; Petkov, Doncho.
This dissertation addresses risk management in the software development context. The discussion commences with the risks in software development and the necessity for a software risk management process. The emergent discourse is based on the shortfalls in current risk management practices, elaborated in the software risk management literature. This research proposes a framework for a field investigation of risk management in the context of a particular software development organization. It was experimentally tested within several companies. This framework was designed to provide an understanding of the software development risk phenomena from a project manager's perspective and to understand how this perspective affects their perception. This was done with respect to the consideration of the advantages and disadvantages of software risk management as regards its applicability or inapplicability, respectively. This study can be used as a precursor to improving research into the creation of new software risk management frameworks.
The applicability of case-based reasoning to software cost estimation.
(2002) Lokotsch, Anton.; Petkov, Don.
The nature and competitiveness of the modern software development industry demands that software engineers be able to make accurate and consistent software cost estimates. Traditionally software cost estimates have been derived with algorithmic cost estimation models such as COCOMO and Function Point Analysis. However, researchers have shown that existing software cost estimation techniques fail to produce accurate and consistent software cost estimates. Improving the reliability of software cost estimates would facilitate cost savings, improved delivery time and better quality software developments. To this end, considerable research has been conducted into finding alternative software cost estimation models that are able produce better quality software cost estimates. Researchers have suggested a number of alternative models to this problem area. One of the most promising alternatives is Case-Based Reasoning (CBR), which is a machine learning paradigm that makes use of past experiences to solve new problems. CBR has been proposed as a solution since it is highly suited to weak theory domains, where the relationships between cause and effect are not well understood. The aim of this research was to determine the applicability of CBR to software cost estimation. This was accomplished in part through the thorough investigation of the theoretical and practical background to CBR, software cost estimation and current research on CBR applied to software cost estimation. This provided a foundation for the development of experimental CBR software cost estimation models with which an empirical evaluation of this technology applied to software cost estimation was performed. In addition, several regression models were developed, against which the effectiveness of the CBR system could be evaluated. The architecture of the CBR models developed, facilitated the investigation of the effects of case granularity on the quality of the results obtained from them. Traditionally researchers into this field have made use of poorly populated datasets, which did not accurately reflect the true nature of the software development industry. However, for the purposes of this research an extensive database of 300 software development projects was obtained on which these experiments were performed. The results obtained through experimentation indicated that the CBR models that were developed, performed similarly and in some cases better than those developed by other researchers. In terms of the quality of the results produced, the best CBR model was able to significantly outperform the estimates produced by the best regression model. Also, the effects of increased case granularity was shown to result in better quality predictions made by the CBR models. These promising results experimentally validated CBR as an applicable software cost estimation technique. In addition, it was shown that CBR has a number of methodological advantages over traditional cost estimation techniques.
The application of computer technology in South African distance education.
(1996) Owusu-Sekyere, Charles.; Meyerowitz, Jane Julia.
The advent of on-line Computer-Assisted Instruction and Computer Mediated Communication may improve instruction and communication in distance education in South African universities. On-line Computer-Assisted Instruction in distance education makes the reinforcement of knowledge both systematic and immediate. With instructional media such printed text, audio-cassettes, radio and television broadcasts the student at a distance is an isolated and passive recipient of knowledge. On-line Computer-Assisted Instruction supported by Computer Mediated Communication for interaction and feedback could close the gaps in time and distance between the teacher and the student in distance education. The current network capabilities of the computer makes it possible for such a student to interact with peers and lecturers before, during and after instructional episodes. Computer Mediated Communication can facilitate the use of electronic messaging such as Electronic Mail, Internet Relay Chat, List Servers, Multi-User Domains and Bulletin Board Services for interactions and feedback. This thesis investigates whether instruction and communication in South African universities with a distance education option can be improved using on-line Computer-Assisted Instruction and Computer Mediated Communication respectively. The thesis also makes proposals for their implementation in South Africa by analysing the applications of computer technology in degree awarding distance education institutions in some developed and developing countries that use on-line Computer-Assisted Instruction and Computer Mediated Communication.
Evaluation of a new online learning resource : the human computer interface design.
(2003) Gachie, Emily Wanjiru.; Amory, Alan M.
With the increasing demand for online learning, well-designed computer online learning resources are indispensable. User interfaces evaluation has become a critical quality attribute of interactive software intended to meet the requirements of the user groups. It is this aspect of adaptations that make them critical for the study of evaluation of user interfaces. This study describes a preliminary evaluation of the user interface design of a new online learning resource (Open Learning System). The main objectives of the study are to investigate the effect of the interaction on the user (usability, efficiency, effectiveness and satisfaction), to assess the extent of the system (resource) functionality and to identify specific problems in the design (aspects of design that cause unexpected results or confusion). This will form part of iterative design and testing process of the new interface, which seeks to evaluate the success of the interface within the framework of the fundamental HCI principles under guidelines of the constructivists learning approach. The Open Learning System (OLS) is grounded on the constructivist-based learning approach. The underlying philosophy of the system assumes when learners are engaged in a social learning context, they actively construct knowledge, therefore the resource is considered as a tool to support learning and not an end in itself. By so doing it is geared to provide greater access to information, support Computer-Mediated Communication (CMC) using tools such as e-mail, chat and discussion foruI? and creating context for learners' work and peer review. A theoretical framework for evaluating the OLS was developed and proposed which comprised of the constructivist epistemology, Rich Environment for Active Learning (REAL), the User Centred Design (UCD) approach and the Human Computer Interface (HCI) design principles. This integrated theoretical framework has been referred to as 'Designing-by-Constructivism' model. The study investigates the use of the OLS by two sets of users: staff members (module creators) and learners (module consumers). In view of the fact that the data collected is qualitative, the approach assumes the use of semi-structured questionnaires, evaluation matrix and interviews. The information/feedback gathered will assist the developers to do preliminary reviews. The study will also be useful to academics pursuing more HCI issues or those with an interest in developing learning resources. The main elements of the 'Designing-by-Constructivism' model were present in the resource. The results analysis indicates that the resource supports collaborative learning and the use of authentic activities in learning. This serves as an intrinsic motivation to most of the users. The results also show a high degree of user satisfaction and appreciation of OLS resource. Largely, the participants are satisfied that the overall OLS design met their needs. The major contribution being, "OLS is interactive and user friendly". However, some users have expressed the desire to have more tools incorporated into the resource, while others have expressed concern about difficulties in logging into the system.
Devising a common vocabulary for a knowledge management university intranet.
(2003) Mahomva, Sarudzai.; Amory, Alan M.
For the past few years, the University of Natal has been using an HTML-driven InnerWeb as its intranet system. The advantages of database driven intranet technologies over static HTML pages are now well established. It was felt that the University should change to a database driven intranet system which would better serve the needs of the University community. The first part of this study was conducted to establish user perceptions and requirements of such an intranet. Results from this study suggested that the functionalities and needs expressed by participants are synonymous with functionalities offered by database driven intranets. The second part of this study was therefore to follow up and prioritise the identified requirements for the main intranet interface to establish a controlled vocabulary and investigate current debate on the possibilities and limitations of intranets as a knowledge management tool. Part of the study took cognisance of Stoke's use inspired research premise by adapting constructivist research philosophy as well as Van den Akker's development research strategy to guide the study. Eclectic mixed methodology as suggested by Reeves guided the research design for this study. Thus data gathering methods which included group and on-line card sorting, semi-structured interviews, category membership expectation tests and prototype validation were used to validate each stage of the development process. Data analysis procedures included using Microsoft Excel to calculate the total score assigned to each item for possible inclusion on the intranet, cluster analysis using IBM EZSort software, analysing interview transcripts using QSR NVlvo software as well as simple eye balling of the category membership expectation data. The initial 93 items for possible inclusion, which were identified at the first part of the study were reduced to 60 items. Some distinct themes, which were identified, include research activities, library, social notices, corporate notices, learning activities, University Policies and Procedures, student activities, staff activities and on-line collaboration . The results of this study suggest that it is challenging to establish vocabulary which is common to the majority of prospective users. Thus, some of the suggested vocabulary for category labels did not have majority consensus. This study also suggests that participants expect a process driven intranet, which offers multidimensional access points and multiple ways to navigate. This implies analysing same data from different viewpoints. Participants want more from an intranet than simple document publishing though a few can not see the intranet beyond a document retrieval tool. The study suggests that users have different needs which could be better addressed by offering customisation and personalisation functionalities to suit users' individual needs. Participants expect to use the intranet as a reliable institutional memory which offers seamless remote access to synchronous and asynchronous communicating tools, access to various forms of digital media, interactive on-line administration functionalities as well as access to on-line academic related activities.
Analysis of cultural and ideological values transmitted by university websites.
(2003) Ramakatane, Mamosa Grace.; Clarke, Patricia Ann.
With the advent of globalisation and new communication technologies, it was inevitable that educational institutions would follow the advertising trend of establishing websites to market their services. This paper analyses the cultural and ideological values transmitted by such university websites. Particular focus is on issues around gender, sexual orientation, race, religion and socioeconomic status. The aim is to analyse consumer reaction to Internet messages conveyed in websites from different cultures, compare them with the intentions of producers and to relate all these back to ideological factors. This study deconstructs content and messages conveyed by University websites to assess the extent to which they might subscribe to particular ideologies (whether overt or covert). The argument that there are hidden ideologies in Web design does not imply that designers or producers intended any conspiracy or deception. Rather, the study compares the organisation's intended image/ethos with that which consumers perceive through their exposure to the website. The methodology was purposive sampling of participants consulted through personal (face-to-face) and interviews conducted online, as well as email-distributed questionnaires.This study uses websites of two universities in the KwaZulu-Natal region of South Africa.
The design and simulation of routing protocols for mobile ad hoc networks.
(2000) Kabeto, Mieso Denko.; Goddard, Wayne.
This thesis addresses a novel type of network known as a mobile ad hoc network. A mobile ad hoc network is a collection of entirely mobile nodes that can establish communication in the absence of any fixed infrastructure. Envisioned applications of these networks include virtual classrooms, emergency relief operations, military tactical communications, sensor networks and community networking. Mobile ad hoc networking poses several new challenges in the design of network protocols. This thesis focuses on the routing problem. The main challenges in the design of a routing protocol for mobile ad hoc networks result from them having limited resources and there being frequent topological changes that occur unpredictably. Moreover, there is no fixed infrastructure that supports routing. The conventional routing protocols are not generally suitable for mobile ad hoc networks, as they cannot react quickly to the changing network topology, cause excessive communication and computation, or converge very slowly creating routing loops. In this thesis we propose two classes of routing schemes for mobile ad hoc networks. The first class is known as Limited Flooding Protocol. The protocol is fully reactive and does not require the computation of routing tables. It uses some basic principles of flooding, but reduces the communication overhead by restricting packet propagation through the network. Several variations of limited flooding are considered including deterministic, randomised and priority-based mechanisms. The main advantage of this protocol is that it can be used in networks with unpredictable topological changes and highly mobile nodes, since maintaining routing table at the intermediate nodes is not required. The second class of routing protocols is based on hierarchical clustering architecture and is intended for use in a relatively low mobility environment. The basic idea of this protocol is to partition the entire network into smaller units known as clusters and define routing mechanisms both within and between clusters using a hierarchical architecture. The main advantage of this architecture is reduction of storage requirements of routing information, communication overhead and computational overhead at each node. Discrete-event simulation is used for modelling and performance evaluation. Various options and variations of the protocols are examined in the…[Page 2 of abstract is missing.]
Spectral techniques for roughness estimation.
(2001) Lewis, Mark.
Roughness is a relatively untouched field considering its significance to natural scientists. In this thesis mathematical techniques for measuring the roughness of signals are constructed and investigated. Both one dimensional and two dimensional signals are tackled. Applications include geological profiles and biological surfaces. Mathematical techniques include Fourier and Wavelet Transforms.
Computer simulation of the two body abrasive wear process.
(2002) Naicker, Theo.; Murrell, Hugh Crozier.
New computer technologies are applied to the classical material engineering two-body abrasive wear process. The computer simulation provides an interactive and visual representation of the wear process. The influence of grit size, grit tip radius and load (at constant workpiece hardness and tool path) on the wear rate, wear coefficient and wear surface topography is predicted. The simulation implements microcutting and microploughing with material displacement to the sides of the groove. The validation of the simulation is demonstrated by comparing with the previous modelling literature and with experiments.
Neural network assisted software engineered refractive fringe diagnostic of spherical shocks.
(1996) Kistan, Trevor.; Sartori-Angus, Alan G.
A shock is essentially a propagating variation in the pressure or density of a medium. If the medium is transparent, such as air, and the shock radially symmetric, the refractive fringe diagnostic can be used to examine its general features. A laser beam probes the shock, the central part of the beam, refracted to different degrees by the different density features within the shock, interferes with itself and with the outer unrefracted part creating a series of coarse and fine fringes. By examining this interference pattern one can gain insight into the density profile underlying the shock. A series of such experiments was conducted by the Plasma Physics Research Institute at the University of Natal in 1990. To model the situation computationally, they developed a ray-tracer which produced interference patterns for modified theoretical density profiles based on those predicted by Sedov. After numerous trials, an intensity pattern was produced which agreed approximately with experimental observations. Thus encouraged, the institute then sought to determine density profiles directly from the interference patterns, but a true mathematical deconvolution proved non-trivial and is still awaited. The work presented in this thesis reconstructs the ray-tracer using software engineering techniques and achieves the desired deconvolution by training a neural network of the back-propagation type to behave as an inverse ray-tracer. The ray-tracer is first used to generate numerous density profile - interference pattern pairs. The neural network is trained with this theoretical data to provide a density profile when presented with an interference pattern. The trained network is then tested with experimental interference patterns extracted from captured images. The density profiles predicted by the neural network are then fed back to the ray-tracer and the resultant theoretically determined interference patterns compared to those obtained experimentally. The shock is examined at various times after the initial explosion allowing its propagation to be tracked by its evolving density profile and interference pattern. The results obtained prove superior to those first published by the institute and confirm the neural network's promise as a research tool. Instead of lengthy trial and error sessions with the unaided ray-tracer, experimental interference patterns can be fed directly to an appropriately trained neural network to yield an initial density profile. The network, not the researcher, does the pattern association.
Using mobile agents to solve the distributed buying problem.
(2002) Reddy, Kamil.; Goddard, Wayne.
This study deals with the Distributed Buying Problem, that is, the problem faced by geographically distributed businesses when it comes to optimising buyer time and global businesses resources. It adopts a software agent-based approach to the problem. A literature survey was carried out to review the relatively new field of software agents and mobile agents in particular. The role of agents in electronic commerce was also studied. A mobile agent system was then designed and implemented to serve as a proof-ofconcept system for an agent-based solution to the problem. The design and implementation are then discussed.
Modelling with mathematica.
(1994) Murrell, Hugh Crozier.; Sartori-Angus, Alan G.
In this thesis a number of mathematical models are investigated with the aid of the modelling package Mathematica. Some of the models are of a mechanical nature and some of the models are laboratories that have been constructed for the purpose of assisting researchers in a particular field. In the early sections of the thesis mechanical models are investigated. After the equations of motion for the model have been presented, Mathematica is employed to generate solutions which are then used to drive animations of the model. The frames of the animations are graphical snapshots of the model in motion. Mathematica proves to be an ideal tool for this type of modelling since it combines algebraic, numeric and graphics capabilities on one platform. In the later sections of this thesis, Mathematica laboratories are created for investigating models in two different fields. The first laboratory is a collection of routines for performing Phase-Plane analysis of planar autonomous systems of ordinary differential equations. A model of a mathematical concept called a bifurcation is investigated and an animation of this mathematical event is produced. The second laboratory is intended to help researchers in the tomography field. A standard filtered back-projection algorithm for reconstructing images from their projections is implemented. In the final section of the thesis an indication of how the tomography laboratory could be used is presented. Wavelet theory is used to construct a new filter that could be used in filtered back-projection tomography.
A real time, system independent, secure, Internet based auctioning system.
(2000) Brown, Cuan.; Murrell, Hugh Crozier.; Swart, Hendrika Cornelia Scott.
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.

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