Thesis (M. Tech.: Information Technology)-Dept. of Information Technology, Durban Institute of Technology, 2005 xiv, 170, [20] leaves / This study examines the efficiency, ease of use and ease of understanding of user interface designs implemented in current e-commerce websites. Four South African based e-commerce websites formed the test cases of this study. Selection of the test cases was based on the results and conclusions of previous surveys conducted by an independent research institution. The outcome of that survey identified the most popular e-commerce websites among South African internet users.

Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Embedded computer systems form part of larger systems such as aircraft or chemical processing facilities. Although testing and debugging of such systems are difficult, reliability is often essential. Development of embedded software can be simplified by an environment that limits opportunities for making errors and provides facilities for detection of errors. We implemented a language and compiler that can serve as basis for such an experimental environment. Both are designed to make verification of implementations feasible. Correctness and safety were given highest priority, but without sacrificing efficiency wherever possible. The language is concurrent and includes measures for protecting the address spaces of concurrently running processes. This eliminates the need for expensive run-time memory protection and will benefit resource-strapped embedded systems. The target hardware is assumed to provide no special support for concurrency. The language is designed to be small, simple and intuitive, and to promote compile-time detection of errors. Facilities for abstraction, such as modules and abstract data types support implementation and testing of bigger systems. We have opted for model checking as verification technique, so our implementation language is similar in design to a modelling language for a widely used model checker. Because of this, the implementation code can be used as input for a model checker. However, since the compiler can still contain errors, there might be discrepancies between the implementation code written in our language and the executable code produced by the compiler. Therefore we are attempting to make verification of executable code feasible. To achieve this, our compiler generates code in a special format, comprising a transition system of uninterruptible actions. The actions limit the scheduling points present in processes and reduce the different interleavings of process code possible in a concurrent system. Requirements that conventional hardware places on this form of code are discussed, as well as how the format influences efficiency and responsiveness. / AFRIKAANSE OPSOMMING: Ingebedde rekenaarstelsels maak deel uit van groter stelsels soos vliegtuie of chemiese prosesseerfasiliteite. Hoewel toetsing en ontfouting van sulke stelsels moeilik is, is betroubaarheid dikwels onontbeerlik. Ontwikkeling van ingebedde sagteware kan makliker gemaak word met 'n ontwikkelingsomgewing wat geleenthede vir foutmaak beperk en fasiliteite vir foutbespeuring verskaf. Ons het 'n programmeertaal en vertaler geïmplementeer wat as basis kan dien vir so 'n eksperimentele omgewing. Beide is ontwerp om verifikasie van implementasies haalbaar te maak. Korrektheid en veiligheid het die hoogste prioriteit geniet, maar sonder om effektiwiteit prys te gee, waar moontlik. Die taal is gelyklopend en bevat maatreëls om die adresruimtes van gelyklopende prosesse te beskerm. Dit maak duur looptyd-geheuebeskerming onnodig, tot voordeel van ingebedde stelsels met 'n tekort aan hulpbronne. Daar word aangeneem dat die teikenhardeware geen spesiale ondersteuning vir gelyklopendheid bevat nie. Die programmeertaal is ontwerp om klein, eenvoudig en intuïtief te wees, en om vertaaltyd-opsporing van foute te bevorder. Fasiliteite vir abstraksie, byvoorbeeld modules en abstrakte datatipes, ondersteun implementering en toetsing van groter stelsels. Ons het modeltoetsing as verifikasietegniek gekies, dus is die ontwerp van ons programmeertaal soortgelyk aan dié van 'n modelleertaal vir 'n modeltoetser wat algemeen gebruik word. As gevolg hiervan kan die implementasiekode as toevoer vir 'n modeltoetser gebruik word. Omdat die vertaler egter steeds foute kan bevat, mag daar teenstrydighede bestaan tussen die implementasie geskryf in ons implementasietaal, en die uitvoerbare masjienkode wat deur die vertaler gelewer word. Daarom poog ons om verifikasie van die uitvoerbare masjienkode haalbaar te maak. Om hierdie doelwit te bereik, is ons vertaler ontwerp om 'n spesiale formaat masjienkode te genereer bestaande uit 'n oorgangstelsel wat ononderbreekbare (atomiese) aksies bevat. Die aksies beperk die skeduleerpunte in prosesse en verminder sodoende die aantal interpaginasies van proseskode wat moontlik is in 'n gelyklopende stelsel. Die vereistes wat konvensionele hardeware aan dié spesifieke formaat kode stel, word bespreek, asook hoe die formaat effektiwiteit en reageerbaarheid van die stelsel beïnvloed.

Thesis (MSc) -- University of Stellenbosch, 2003. / ENGLISH ABSTRACT: A need for intelligent robotic machines is identified. Research and experiments have focussed on stable, or relatively stable, dynamic simulated systems to demonstrate the feasibility of embedding advanced AI into dynamic physical systems. This thesis presents an attempt to scale the techniques to a dynamically highly unstable system - the coordination of movements in a humanoid model. Environmental simulation, articulated systems and artificial intelligence methods are identified as three essential layers for a complete and unified approach to embedding AI into robotic machinery. The history of the physics subsystem for this project is discussed, leading to the adoption of the Open Dynamics Engine as the physics simulator of choice. An approach to articulated systems is presented along with the EBNF of a hierarchical articulated system that was used to describe the model. A revised form of evolution is presented and justified. An AI model that makes use of this new evolutionary paradigm is introduced. A variety of AI variants are defined and simulated. The results of these simulations are presented and analysed. Based on these results recommendations for future work are made. / AFRIKAANSE OPSOMMING: Die beheer van dinamiese masjiene, soos intelligente robotte, is tans beperk tot fisies stabilie - of relatief stabiele - sisteme. In hierdie tesis word die tegnieke van kunsmatige intelligensie (KI) toegepas op die kontrole en beheer van 'n dinamies hoogs onstabiele sisteem: 'n Humanoïede model. Fisiese simulasie, geartikuleerde sisteme en kunmatige intelligensie metodes word geïdentifiseer as drie noodsaaklike vereistes vir 'n volledige en eenvormige benadering tot KI beheer in robotte. Die implementasie van 'n fisiese simulator word beskryf, en 'n motivering vir die gebruik van die sogenaamde "Open Dynamics Engine" as fisiese simulator word gegee. 'n Benadering tot geartikuleerde sisteme word beskryf, tesame met die EBNF van 'n hierargiese geartikuleerde sisteem wat gebruik is om die model te beskryf. 'n Nuwe interpretasie vir evolusie word voorgestel, wat die basis vorm van 'n KI model wat in die tesis gebruik word. 'n Verskeidenheid van KI variasies word gedefineer en gesimuleer, en die resultate word beskryf en ontleed. Voorstelle vir verdere navorsing word gemaak.

The rise of business-oriented and commercial applications for Grid computing environments has recently gathered pace. Grid computing traditionally has been linked with scientific environments, where heterogeneous resources provided by Grid systems and infrastructures were employed for carrying out computationally-intensive and data-intensive scientific experiments or applications that may have not been possible before. The natural progression is that business-oriented applications will look to build on this success and utilise the large number of heterogeneous Grid resources including computational resources such as CPUs and memory and storage resources such as disk space, potentially available. The success of introducing these applications into the mainstream is directly related to whether service providers can deliver a level of Quality of Service (QoS) to a consumer and the ability of the consumer to request high-level QoS such as the numbers of CPUs required or the RAM required. QoS refers to the guidelines and requirements requested by a user/consumer from the service providers and resources. The communication and agreement establishment processes between user and provider must be defined clearly to accommodate a new type of user where knowledge of the underlying infrastructure cannot be assumed. QoS parameters have generally been defined at the Grid resource level using low level definitions. This tailors to specific applications and models related to scientific domains where brokering, scheduling and QoS delivery is designed for specific applications within specific domains. This thesis presents a flexible model for high-level QoS requests. Business Grid Quality of Service (BGQoS) is introduced for business-oriented and commercial Grid applications which may wish to make use of the resources made available by Grid system environments. BGQoS allows GRCs (Grid Resource Consumers) to specify varying types of high-level QoS requirements which are delivered via querying up-to-date resource information, matchmaking and monitoring operations. Moreover, we present dynamically calculated metrics for measuring QoS such as reliability, increasing the accuracy of meeting the GRC’s requirements. On the other hand GRPs (Grid Resource Provider) are also capable of advertising their resources, their capabilities, their usage policies and availability both locally and globally. This leads to a flexible model that could be carried across domains without altering the core operations and which could easily be expanded in order to accommodate different types of GRC, resources and applications.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2007. / In this thesis we present a human-computer interface (HCI) system for disabled persons using only a basic web camera. Mouse movements are simulated by small movements of the head, while clicks are simulated by eye blinks. In this study, a system capable of face tracking, eye detection (including iris detection), blink detection and finally skin detection and face recognition has been developed. A detection method based on Haar-like features are used to detect the face and eyes. Once the eyes have been detected, a support vector machines classifier is used to detect whether the eye is open or closed (for use in blink detection). Skin detection is done using K-means clustering, while Eigenfaces is used for face recognition. It is concluded that using a web camera as a human-computer interface can be a viable input method for the severely disabled.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2007. / Next-generation nanosatellites are becoming a very cost effective solution to gain access to space. Modern manufacturing technology together with low power low cost devices makes the development of nanosatellites, using standard industrial components, very attractive. A typical nanosatellite will have only one microprocessor, capable of performing all the computing tasks onboard the satellite - housekeeping, AODC (Attitude and Orbit Control) and instructing the different payloads aboard the satellite. One of the major requirements was to choose a processor from a dominant manufacturer in the market that will still be available for future satellite missions. Just as the 8051 dominated the 8-bit market, the ARM7 processor is fast becoming a market leader in the segment for 16-bit applications. ARM processors has also been used much in handheld devices in recent years - which emphasize the low power requirements and stability of these processors in embedded applications. This thesis investigates the different processors that are currently available. A complete system design is done, taking into account all the different modules needed onboard a very small Low Earth Orbit (LEO) satellite. Finally, some test results are given showing how this system can be reliably used onboard a nanosatellite in future.

published_or_final_version / Education / Master / Master of Science in Information Technology in Education

published_or_final_version / Computer Science / Master / Master of Philosophy

This dissertation describes research in the application and evaluation of a Kohonen Self-Organizing Map (SOM) to the problem of classification of Electronic Brainstorming output. Electronic Brainstorming is one of the most productive tools in the Electronic Meeting System called GroupSystems. A major step in group problem solving involves the classification of Electronic Brainstorming output into a manageable list of concepts, topics, or issues that can be further evaluated by the group. This step is problematic due to the information overload and cognitive load of the large quantity of data. This research builds upon previous work in automating the classification process using a Hopfield Neural Network. Evaluation of the Kohonen output in comparison with the Hopfield and human expert output over the same set of data found that the Kohonen SOM performed as well as a human expert in the recollection of associated term pairs and outperformed the Hopfield Neural Network algorithm. Using information retrieval measures, recall of concepts using the Kohonen algorithm was equivalent to the human expert. However, precision was poor. The graphical representation of textual data produced by the Kohonen SOM suggests many opportunities for improving information management of textual electronic information. Increasing uses of electronic mail, computer-based bulletin board systems, and world-wide web textual data suggest an overwhelming amount of textual information to manage. This research suggests that the Kohonen SOM may be used to automatically create "a picture that can represent a thousand (or more) words."

Internet of things (IoT) generates massive amount of heterogeneous data, which should be efficiently utilized to support services in different domains. Specifically, data need to be supplied to services by understanding the needs of services and by understanding the environment changes, so that necessary data can be provided efficiently but without overfeeding. However, it is still very difficult for IoT to fulfill such data supply with only the existing supports of communication, network, and infrastructure; while the most essential issues are still unaddressed, namely the heterogeneity issue, the recourse coordination issue, and the environments’ dynamicity issue. Thus, this necessitates to specifically study on those issues and to propose a method to utilize the massive amount of heterogeneous data to support services in different domains. This dissertation presents a novel method, called the data-centric network of things (DNT), which handles heterogeneity, coordinates resources, and understands the changing IoT entity relations in dynamic environments to supply data in support of services. As results, various services based on IoT (e.g., smart cities, smart transport, smart healthcare, smart homes, etc.) are supported by receiving enough necessary data without overfeeding. The contributions of the DNT to IoT and big data research are: firstly the DNT enables IoT to perceive data, resources, and the relations among IoT entities in dynamic environments. This perceptibility enhances IoT to handle the heterogeneity in different levels. Secondly, the DNT coordinates IoT edge resources to process and disseminate data based on the perceived results. This releases the big data pressure caused by centralized analytics to certain degrees. Thirdly, the DNT manages entity relations for data supply by handling the environment dynamicity. Finally, the DNT supply necessary data to satisfy different service needs, by avoiding either data-hungry or data-overfed status.