This thesis deals with the analysis of a Wired High Speed Serial Data Link (PAM2) which is commonly used throughout the data-communications and tele-communications industry. The goal of this study is to build a scalable simulation tool using Matlab that ultimately uses Receiver Bit Error Ratio (BER) as the metric for data link health. This study is also designed to aid in link specification development. The Matlab and theoretical development is broken up into three sections being Transmitter (TX), Channel (Hs) and Receiver (RX). Realistic noise impairments can be added to each section along the signal path creating signal stresses commonly seen in data center applications. The TX function is designed to create random and periodic timing jitter, voltage noise and deterministic pre-distortion filtering effects. For the channel response s-parameters are used as the model result for many commonly seen channel loss and reflection scenarios. The RX model uses signal to noise ratio and vertical eye margin to determine the equalized link BER. The study results show many tradeoffs between noises, RX Equalizer, RX gain and RX BER. The simulation results also reveal that there is no closed form solution for converging the modern closed-eye PAM2 detector.

Design guidelines are used in interaction design (IxD) for physical design and for evaluating the usability of designs and interactive products. Guidelines are widely used for physical design and evaluation, but have a number of problems. IxD patterns have been proposed as an alternative to guidelines, as they are claimed to have several advantages over guidelines. A small number of empirical studies provide evidence that patterns are beneficial when used in IxD. Additional research on the usefulness of IxD patterns is required. The primary research question investigated in this thesis was thus: How useful are IxD patterns as physical design and evaluation aids in IxD, as compared to design guidelines? The role of guidelines and patterns as design and evaluation aids in IxD was investigated and a comparison of guidelines and patterns, based on a set of guideline and pattern properties, was conducted. The concept of pattern and guideline usefulness was explored and a research agenda for guidelines and patterns was identified, together with a set of research questions for an empirical study. The empirical study of the use of patterns for evaluation, redesign and new design, as compared to guidelines, was conducted at the Nelson Mandela Metropolitan University in 2004. The participants were a purposive sample of post-graduate Computing students, who were regarded as novice interaction designers. Two equivalent groups were formed, one that used patterns and one that used guidelines. Patterns were found to be as useful as guidelines when used as evaluation aids. Guidelines and patterns were identified as effective tools for identifying and explaining usability issues and design features. Best-effort matched sets of guidelines and patterns produced substantially different result sets when used to identify issues and features, with fairly low overlap. A substantial evaluator effect was observed for the use of guidelines and patterns for evaluation, and the results obtained were similar to those obtained by Molich et al. in their Comparative Usability Evaluation (CUE) studies. There was no statistically significant difference between the effectiveness of guidelines and patterns for evaluation. There was also no statistically significant difference between the perceived efficiency, effectiveness and satisfaction in use of guidelines and patterns for evaluation. Guidelines and patterns were found to be used in similar ways for evaluation. Patterns were found to be more effective than guidelines for redesign. Patterns were found to be as useful as guidelines when used for new design. There was no statistically significant difference between the effectiveness of guidelines and patterns for new design. There was also no statistically significant difference between the perceived efficiency, effectiveness and satisfaction in use of guidelines and patterns for redesign and new design. Guidelines and patterns were found to be used in similar ways for design. There was no statistically significant difference between the perceived usefulness of the format, content, ease of learning, and usefulness as personal and shared design languages, of guidelines and patterns. Both participant groups were equally agreeable to using guidelines and patterns in the future. The perceived usefulness of pattern collections was found to depend on the usability of the collection interface and the content quality of the patterns. The results of the empirical study thus provided empirical evidence that patterns were as useful as guidelines for evaluation and new design, and were perceived as positively as guidelines were. Patterns were found to be superior to guidelines for redesign. Patterns can therefore be used with a measure of confidence as early stage design aids for physical design and evaluation in the future. In addition to these findings, a number of opportunities for further research were identified.

Mobile devices today frequently serve as platforms for the visualisation of map-based data. Despite the obvious advantages, mobile map-based visualisation (MMV) systems are often difficult to design and use. Limited screen space, resource constraints and awkward interaction mechanisms are among the many problems with which designers and users have to contend. Adaptive user interfaces (AUIs), which adapt to the individual user, represent a possible means of addressing the problems of MMV. Adaptive MMV systems are, however, generally designed in an ad-hoc fashion, making the benefits achieved difficult to replicate. In addition, existing models for adaptive MMV systems are either conceptual in nature or only address a subset of the possible input variables and adaptation effects. The primary objective of this research was to develop and evaluate an adaptive MMV system using a model-based approach. The Proteus Model was proposed to support the design of MMV systems which adapt in terms of information, visualisation and user interface in response to the user‟s behaviour, tasks and context. The Proteus Model describes the architectural, interface, data and algorithm design of an adaptive MMV system. A prototype adaptive MMV system, called MediaMaps, was designed and implemented based on the Proteus Model. MediaMaps allows users to capture, location-tag, organise and visualise multimedia on their mobile phones. Information adaptation is performed through the use of an algorithm to assist users in sorting media items into collections based on time and location. Visualisation adaptation is performed by adapting various parameters of the map-based visualisations according to user preferences. Interface adaptation is performed through the use of adaptive lists. An international field study of MediaMaps was conducted in which participants were required to use MediaMaps on their personal mobile phones for a period of three weeks. The results of the field study showed that high levels of accuracy were achieved by both the information and interface adaptations. High levels of user satisfaction were reported, with participants rating all three forms of adaptation as highly useful. The successful implementation of MediaMaps provides practical evidence that the model-based design of adaptive MMV systems is feasible. The positive results of the field study clearly show that the adaptations implemented were highly accurate and that participants found these adaptations to be useful, usable and easy to understand. This research thus provides empirical evidence that the use of AUIs can provide significant benefits for the visualisation of map-based information on mobile devices.

This study describes first and second year university physics students' understanding and reasoning of the concepts, angular speed and angular acceleration. The analysis was based on student responses to various tasks presented to them during one hour long interviews. These responses were characterized from a phenomeno graphic research perspective developed by Marton (1981) and his colleagues at Gothenburg University in Sweden. The findings of the study are described by categories of description and by categories of reasoning. Categories of description characterize; students' conceptualizations of angular speed from different frames of reference, and the ways in which students make comparisons of the angular speeds of two objects. Categories of reasoning characterize the ways in which students were thought to reason about the concepts of angular speed and angular acceleration in several task settings. Interpretation of these findings are discussed with reference to the role a typical introductory physics textbook may have had in shaping the way in which students think about these angular kinematic concepts. Finally, instructional implications and directions for future research are given. / Education, Faculty of / Curriculum and Pedagogy (EDCP), Department of / Graduate

Utbildning skapar de grundläggande förutsättningarna för invandrare att integreras ekonomiskt och socialt i ett samhälle. Denna uppsats undersöker vilken roll integrationspolitisk inriktning  har i integrationsprocessen inom utbildning genom att jämföra två länder där frågan om integration ständigt är aktuell, Sverige och Australien. Studien följer en mest-lika design som bygger på att Sverige och Australien antas vara mycket lika vad gäller integrationspolitiken inom utbildning men trots detta påvisar olika integrationsutfall. Syftet med uppsatsen är att undersöka eventuella skillnader i ländernas integrationspolitiska inriktning som kan tänkas förklara de olika integrationsutfallen. Som metod för att fullgöra syftet används både kvalitativ textanalys och intervjuer. Uppsatsen når slutsatsen att Australien i en högre grad en Sverige tycks fokusera på integrationspolitik avseende interkulturellt lärande och att detta i sin tur utgör en möjlig förklaring till att Australien påvisar bättre integrationsutfall än Sverige.

M.Sc. / The work is based on a project done by SAMES (South African Micro Electronic Systems) for the local production of an integrated circuit that previously had to be imported. The circuit finds application in the telecommunications field where it controls loop disconnect dialling in the telephones. The mechanical disc dial is thus replaced by an electronic network that makes use of push-button entry and full digital out-dialling. The push-button telephone is compatible with the rotary disc dial telephone with advantages in reliability, speed and ease of use. An access pause and re dial facility add towards a more efficient telephone. The circuit was bought from an American company for manufacturing purposes. A process fit and circuit modifications were done for product ion on the CMOS process line at SAMES. The work includes a circuit- and process study with modifications, computer aided design, prototype production and analysis. The original circuit is called the General Instruments AY-5-9151D and the re-designed version the SAMES SA 9151-A2.

Please read the abstract in the section 00front of this document / Dissertation (MEng (Mechanical Engineering))--University of Pretoria, 2007. / Mechanical and Aeronautical Engineering / unrestricted

Increasing power dissipation and chip densities in the rapidly evolving electronics cooling industry are causing an ever increasing need for the tools and methods necessary for electronic systems design and optimisation. Modern electronic systems have the capacity to produce significant amounts of heat which, if not removed efficiently, could lead to component failure. The most common technique of heat removal is by making use of a heat spreader, or so¬-called heat sink. These devices are excellent heat conductors with a large surface area to volume ratio, and cooled through either natural or forced convection. Despite the advantages of these devices, there are serious consequences involved in the application of heat sinks. The required size of a heat sink may limit the miniaturisation of a product, while inadequate design, due to a lack of understanding of the flow physics, may lead to premature component failure. It is therefore crucial that an optimal heat sink design is achieved for every particular application. In the past, both heat sink design and optimisation have occurred mostly through experimental characterisation of heat sinks, which was not always particularly successful or accurate. Recent rapid developments in computer technology have led to the availability of various computational fluid dynamics or CFD software packages, with the capability of solving the discretized form of the conservation equations for• mass, momentum, and energy to provide a solution of the flow and heat fields in the domain of interest. This method of using the fundamental flow physics is currently the most complete way to determine the solution to the heat sink design and optimisation problem. It does unfortunately have the drawback of being computationally expensive and excessively time consuming, with commercial software prices being financially restrictive to the average designer. The electronics cooling community has subsequently identified the need for so-called "compact models" to assist in the design of electronic enclosures. Compact models use available empirical relations to solve the flow field around a typical heat sink. Current models require significantly less computational power and time compared to CFD analysis, but have the drawback of reduced accuracy over a wide range of heat sink geometries and Reynolds numbers. This is one of the reasons that compact modelling of heat sinks remain an international research topic today. This study has focused on the CFD modelling of a variety of forced flow longitudinal fin heat sinks with tip clearance. Tip clearance allows the flow to bypass the heat sink and downgrade its thermal performance. The flow bypass phenomenon, general flow behaviour, and pressure loss characteristics were investigated in detail. Thermal modelling of the heat sinks was left for future study. The flow information provided by the CFD analysis was combined with data available from literature to develop an improved compact flow model for use in a variety of practical longitudinal fin heat sinks. The new compact model leads to a 4.6 % improvement in accuracy compared to another leading compact model in the industry, and also provides more localised flow information than was previously available from compact modelling. <p The study therefore contributed significantly towards the general understanding and prediction of forced flow behaviour in longitudinal fin heat sinks with tip bypass, using both CFD analysis and the compact modelling approach. The new improved compact model may now be extended and incorporated together with the relevant flow details from the CFD analysis in a total package, solving for the flow and heat fields of forced flow longitudinal fin heat sinks. The study therefore assists in the global effort of making the confident and accurate use of compact modelling in modem electronic systems design and optimisation a practical reality. / Dissertation (M Eng (Mechanical Engineering))--University of Pretoria, 2007. / Mechanical and Aeronautical Engineering / unrestricted

<p>Autonomous Mobile Robots (AMR) and IoT (Internet of Things) devices have substantial potential to increase productivity in Small and Medium Enterprises (SME). However, factors such as high costs involved in setting up and maintaining AMR automation and deficit of programming expertise among factory workers render AMR automation uneconomical for SMEs. </p><p><br></p><p></p><p>Visual Programming can be used in the spatial context of the operating environment to enable closer mental models at the right level of abstraction for novice programmers. In this thesis, we develop a system for deploying a Spatially Situated Visual Language (SSVL) for programming robot-IoT workflows. To address the challenges of interoperability, scalability, and versatility of industrial machinery, we develop a novel communication protocol based on the Resource Description Framework (RDF). Our communication protocol forms the basis of a system architecture that integrates SSVL, IoT devices, and mobile robots that enables factory workers to program AMR workflows. We design, implement and validate the system and the architecture following the systems engineering approach. To evaluate the system developed in an industrial context, we deploy the system to author AMR workflows for material handling application for an SME painting factory.</p><p></p>

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