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Thesis (MScEng) -- Stellenbosch University, 2003. / INTRODUCTION: The Medical Radiation department at iThemba LABS provides proton beam therapy facilities for irradiation of intracranial, head and neck lesions. Proton radiation treatment offers a number of advantages over alternative radiation therapy modal- ities. The most significant advantage is the ability to localize the dose to the lesion or target volume [16]. Lesions are located by means of medical imaging processes, such as Computer Tomography (CT) or Magnetic Resonance Imaging (MRI) scans. Patient treatment commences at the existing treatment facility of iThemba LABS. The patient positioning system that is currently in use at this facility was designed for only one horizontal beam delivery system and a limited number of treatment positions. The possibility of acquiring an additional beam delivery system and im- proving the utilization of the system resulted in plans to expand the current proton therapy capabilities. These plans resulted in the development of a new treatment vault, complete with a new patient positioning system. The new vault will cater for two beam delivery systems and expand current treatment positions.

Thesis (MSc)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: The recognition and description of relief features from their contour patterns is recognized as the main challenge in topographic map education. Conducting field exercises can solve this problem, but can be very time consuming. Modern technology, however, provides an alternative teaching technique by creating depictions of terrain. Important issues raised by this new approach include questions such as what these depictions should look like and how it should be presented to the user. Research presented here aims to address these issues by constructing design guidelines for terrain depiction. These design guidelines were derived from previous research and case studies. The guidelines focussed on research about how people perceive different representations of terrain and how these representations should optimally be presented. The design guidelines were constructed from research done in diverse fields such as cognitive psychology, cartography and engineering. Results of this research revealed that in order to develop an effective terrain visualization tool, it is crucial to incorporate different fields of expertise. The design guidelines were implemented with ArcView GIS and its 3D Analyst extension, which has the ability to display spatial data in three dimensions. The final product is called Terrain Visualization Tool 1.1 (TVT) and was created by customizing an ArcView GIS project (TV BUILDER) and constructing a Website (TV VIEWER). TV BUILDER creates the visualization data in the form of 20 web pages per topographic area and links them to TV VIEWER that serves as a platform to view the data. The design guidelines were implemented successfully and show the advantages of using Geographical Information Systems (GIS) in related research. / AFRIKAANSE OPSOMMING: Die identifisering en beskrywing van landskapelemente vanaf hul kontoere is geidentifiseer as die primere uitdaging in topografiese kaartonderrig. Hierdie probleem kan oorkom word deur kaartleesoefeninge in die veld te onderneem, maar dit neem baie tyd in beslag. Modeme tegnologie maak ‘n alternatiewe onderrigmedium moontlik deur die skep van verskillende landskapsuitbeeldings. Hierdie alternatief laat die vraag ontstaan hoe die uitbeeldings moet lyk en hoe dit aan die gebruiker aangebied moet word. Die doel van hierdie navorsing spreek hierdie vrae aan deur ontwerpriglyne vir landskap uitbeelding daar te stel. Die ontwerpriglyne is saamgestel deur bestudering van vorige navorsing en studies wat op hierdie gebied gedoen is. Die riglyne fokus veral op navorsing wat mense se reaksie op verskillende landskapuitbeeldings ondersoek. Die ontwerpriglyne is egter saamgestel deur navorsing wat gedoen is in velde soos kognitiewe sielkunde, kartografie en ingenieurswese. Hierdie navorsing het bewys dat inkorporasie van verskillende studievelde in die ontwikkeling van terrein visualiseringstoepassings essensieel is. Die riglyne is geimplementeer deur gebruik te maak van ArcView GIS en die 3D Analyst uitbreiding wat die vermoe het om data in drie dimensies uit te beeld. Die finale produk genaamd Terrain Visualization Tool 1.1 (TVT) bestaan uit twee komponente, naamlik ‘n aangepaste ArcView GIS projek (TV BUILDER) en ‘n webwerf (TV VIEWER). TV BUILDER skep die landskapsuitbeeldings van een topografiese area in die vorm van 20 web bladsye en verbind dit met TV VIEWER, wat as ‘n platform dien om die landskap uitbeeldings te beskou. Die ontwerpriglyne is suksesvol geimplementeer, wat die voordele van Geografiese Inligtingstelsels (GIS) in hierdie en soortgelyke toekomstige navorsing demonstreer.

The work presented in this thesis centres on the development of a work-flow in which coarse-grained molecular dynamics (MD) simulations of a planar phospholipid bilayer, containing membrane proteins, is used to parameterize a larger-scale simplified bilayer model. Using this work-flow, repeat simulations and simulations of larger systems are possible, better enabling the calculation of bulk statistics for the system. The larger-scale simulations can be run on commercial hardware, once the initial parameterization has been performed. In the simplified representation, each protein was initially only represented by the position of its centre of mass and later with the inclusion of its orientation. The membrane protein used throughout most of this work was the bacterial outer membrane protein NanC, a member of the KdgM family of proteins. To parameterize the motion and interaction of proteins using MD, the potential of mean force (PMF) for the pairwise association of two proteins in a bilayer was calculated for a variety of orientational combinations, using a modified umbrella sampling procedure. The relative orientations chosen represented extreme examples of the contact regimes between the two proteins: they approximately corresponded to maxima and minima of the solvent inaccessible surface area, calculated when the proteins were in contact. These PMFs showed that there was a correlation between the buried surface area and the depth of the potential well in the PMF; this is something that, to date, has only been observed in these relatively-'featureless' membrane proteins (but is seen in globular proteins), where the effect of the interactions with lipids in the bilayer plays a larger role. Features in the PMF were observed that resulted from the preferential organization of lipids in the region between the two proteins. These features were small wells in the PMF, which occurred at protein separations that corresponded to the intervening lipids being optimally packed between the proteins. This result further highlighted the role that the lipids in the bilayer played in the interaction between the NanC proteins. The simplified bilayer model was parameterized using the PMFs and the relationship between buried surface area and potential well depth. The initial model included only the proteins' positions. A series of Monte Carlo simulations were performed in order to compare the system behaviour to that of an equivalent MD simulation. Initially, the MD simulation and our parameterized model did not show a good agreement, so a Monte Carlo scheme that incorporated cluster-based movements was implemented. The agreement between the MD simulation and the simulations of our model using the cluster-based scheme, when comparing diffusive and clustering behaviour, was good. Including the orientation-dependent features of the parameterization resulted in the emergence of behaviour that was not clearly detectable in the MD simulation. Finally, attempts were made to parameterize the model using PMFs for the association of rhodopsin from the literature. Rhodopsin was a much more complicated protein to represent: there was not a clear correlation between surface area and the features of the PMF, and the geometry of the interaction between two rhodopsins was more complicated. Simulations of the 'rows-of-dimers' system of rhodopsin, observed in disc membranes, was not entirely well represented by the model; for such a closely packed system, where the number of lipids is much closer to the number of proteins, the use of an implicit-lipid model meant that the effect of the reduced lipid mobility was not adequately captured. However, the model accurately captures the orientational composition of the system. Future work should be focussed on incorporating explicit representations of the lipid in the system so that the behaviour of close-packed systems are better represented.

This study investigated the predictive value of time on-task and error scores on tests administered through Control Data Corporation PLATO interactive computer graphics simulation as predictors of errors and time on-task for inertial navigation system equipment operation. In addition, the correlation between simulated pass/fail error and time on-task scores, and subsequent pass/fail criteria using actual equipment was investigated.

D.Ing. / A simulation system of an industrial robot, within a manufacturing environment for its intelligent interaction within the cell as well as its control via the Internet is presented. The simulation verification in an experimental cell in which an ABB lRB 2400 robot operates is discussed. Sensors employed throughout the cell to supply the input for robot action through an expert system are described. The robot interacts with several task groups of the cell, production equipment, materials handling and assembly. The cell use of a PC, directly linked to the robot and other equipment and sensors for, cell control is explained. The PC has full on-line control of all equipment while the simulation runs simultaneously with the experimental set-up. The system incorporates robot and cell control via the Internet. To add additional intelligence to the cell a transponder system, tagging each part in the robotic cell, is also implemented. This enables each part to be identified by the robot, as well as for the robot to interact with each transponder.

South Africa endorsed a world trade accord ratified in Geneva on December 13, 1993. To promote world economic growth, the General Agreement on Tariffs and Trade (GATT) aimed to slash duties on 8000 categories of manufactured goods. Tariff barriers have declined significantly and are now approaching trivial levels (Hill, 1999, p163). Unfortunately, South Africa is ranked near the bottom of the World Competitiveness Report (Cheales, 1995, p8). Increased foreign competition has caused many South African companies to search for techniques that will improve their overall performance. Unless these techniques can be identified and implemented timeously, some companies may fail to remain competitive. This research addresses the lack of awareness in the Eastern Cape (SA) and utilisation of two techniques used successfully in the USA (and elsewhere in developed countries) namely, Constraint Management and simulation. The overall objective was to develop a method of convincing industry management of the benefits of the two techniques. The approach adopted was to use simulation to prove Constraint Management. To achieve this objective a comprehensive literature survey was performed to determine the logic of each technique and the associated benefits. The next step was to determine the levels of awareness among industry practitioners and managers. Managers, engineers and academics were requested to complete questionnaires in order to determine awareness and utilisation of each technique as well as factors that prevented the application of both. The simulation modeling process was examined in order to verify the logic of simulation and a model of a manufacturing system was developed. Constraint Management principles were then applied to the model in a series of experiments. This process was then developed into a manual that could be used to address the lack of awareness and utilisation of both Constraint Management and simulation. The manual was tested on a group of BTech students and industry practitioners in order to establish whether its use would be effective in raising awareness, understanding and utilisation. The outcome was positive and it was established that this technique was effective.

Thesis (M. Ed.) -- University of Limpopo, 2017. / One of the effective ways of teaching science is by developing the thinking abilities of individuals by allowing them to engage in enquiry-based learning. Computer simulation (CS) can help improve understanding of scientific concepts and enhance conceptual development and performance. This study focused on exploring learners’ conceptual development using CS in Grade 10 science class. A pre- and post-test research designs were used. 105 Grade 10 learners participated: 53 from one whole class were assigned to an Experimental Group (EG) and 52 from another class to a Control Group (CG). The EG was taught using CS while the CG was taught using the traditional approach. Data on learners’ performance were collected using a performance test and interviews were employed to collect data on learners’ attitudes towards science. The results revealed that the EG performed better than the CG (t-test, p < 0.05), (ANCOVA, p < 0.01). Girls in the EG performed better than girls from the CG (t-test, p < 0.05), and independent sample t-test revealed that girls in the EG were in the same range with boys after intervention suggesting that CS did not discriminate against gender in this study. Furthermore, the results from interviews indicate that learners from EG exhibited positive attitudes towards science, unlike their counterparts from the CG. This suggests that learners from the EG may have been excited to observe phenomena on the screen of a computer that they would otherwise not do due to lack of laboratory equipment in their school.

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