Thesis (Dr. rer. nat.)--Technischen Fakultät der Christian-Albrechts-Universität zu Kiel, 2008. / Reproduced from PDF. Includes bibliographical references (p. 237-250).

Thesis--George Washington University. / Includes bibliographical references (p. 98-101).

Thesis--George Washington University. / Includes bibliographical references (p. 98-101).

Thesis (MEng)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: Satellites are not all made equal. The large number of possible orbits, desired functionality and budget constraints are but a few of the factors that influence the design of a satellite. Given a particular set of design requirements, a number of designs may meet these requirements. Each of these designs will typically entail a trade-off between a number of (conflicting) parameters, whilst still satisfying the system requirements. The On-Board Computer (OBC) of a satellite, the satellite subsystem primarily responsible for the operational control of a satellite, can consequently be designed in any of a number of different ways. As the factors that influence the flight performance of an OBC differs to those of a terrestrial computer, the OBC design will therefore be significantly different. A high-level overview of the factors that impact OBC design and operation is presented. Improvements to the existing designs are proposed. In conclusion, a number of guidelines for a future OBC design also are given. / AFRIKAANSE OPSOMMING: Elke satelliet het unieke eienskappe wat bepaal word deur onderandere, die teiken wentelbaan, verwagte funksionaliteit en koste oorweegings. Vir 'n spesefieke stelselontwerp bestaan daar 'n aantal moontlike ontwerpe wat aan die stelsel vereistes voldoen. Elk van hierdie ontwerpe sal tipies behels dat verskillende parameters teen mekaar afgespeel word, terwyl die stelsel vereistes steeds aan voldoen word. Die Aanboord Rekenaar (AR) van 'n satelliet, die satelliet substelsel hoofsaaklik verantwoordelik vir die beheer van die satelliet, kan vervolgens uit een van veele moontlike ontwerpe bestaan. Aangesien die faktore wat die werkverrigting van 'n AR beinvloed verskil van die van 'n rekenaar wat op die aard oppervlak gebruik word, sal die AR ontwerp dienooreenkomstig verskil. 'n Hoevlak oorsig van die faktore wat AR ontwerp beinvloed sal gegee word. Verbeteringe wat aan die huidige AR ontwerpe gedoen kan word sal bespreek word. Ter afsluiting sal 'n aantal riglyne vir toekomstige AR ontwerpe gegee word.

Thesis (MScEng)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: The use of commercial-off-the-shelf (COTS) components and emerging technologies in satellite systems has become increasingly popular over the past few years. This is mainly due to advances in radiation shielding and system-level reliability improving techniques. The use of a new generation commercial processor in the design of a satellite's on-board computer (OBC) is now considered a feasible option. The aim of this thesis was to evaluate the use of a commercial grade ARM processor in a low earth orbit (LEO) microsatellite on-board computer. The process began with the selection of the most suitable ARM processor for an aBC design. A typical aBC system was developed for the chosen processor, in order to test its functionality and performance in anOBC design. / AFRIKAANSE OPSOMMING: Die afgelope paar jaar het die gebruik van gewone kommersiële komponente en die nuutste tegnologie in satelliet stelsels heelwat toegeneem. Dit kan grootliks toeskryf word aan die vordering in bestralings afskerming en stelselvlak betroubaarheid tegnieke. Die gebruik van 'n nuwe generasie kommersiële verwerker in die ontwerp van 'n satellite aanboord rekenaar (AR) is nou prakties uitvoerbaar. Die doel van hierdie tesis was om die gebruik van 'n ARM verwerker in 'n lae aardwentelbaan mikrosatelliet aanboord rekenaar te evalueer. Eerstens moes die mees geskikte kommersiële ARM verwerker vir 'n AR ontwerp gevind word. Daarna is 'n tipiese AR stelselontwikkel om die verwerker se funksionaliteit en werkverrigting te toets.

This research is concerned with some aspects of the retrieval of information from database systems by casual, naive computer users. A "casual user" is defined as an individual who only wishes to execute queries perhaps once or twice a month, and a "naive user" is someone who has little or no expertise in operating a computer and, more specifically for the purposes of this study, is not practiced at querying a database. The research initially focuses on a specific group of casual, naive users, namely a group of clinicians, and analyzes their characteristics as they pertain to the retrieval of information from a computer database. The characteristics thus elicited are then used to create the requirements for a database interface that would, potentially, be acceptable to this group. An interface having the desired requirements is then proposed. This interface consists, from a user's perspective, of three basic components. A graphical model gives a picture of the database structure. Windows give the ability to view different areas of the database, physically group together items that come under one logical heading and provide the user with immediate access to the data item names used by the system. Finally, a natural language query language provides a means of entering a query in a syntax (that of ordinary English) which is familiar to the user. The graphical model is a logical abstraction of the database. Unlike other database interfaces, it is not constrained by the model (relational, hierarchical, network) underlying the database management system, with the one caveat that the graphical model should not imply any connections which cannot be supported by the management system. Versions of the interface are implemented on both eight-bit and sixteen-bit microcomputers, and testing is conducted in order to validate the acceptability of the interface and to discover the level of graphical model which the users find most acceptable. The results of this testing are reported and further areas for research suggested.

This project is a graphical user interface for managing log information. Logging is an important componet of a software development cycle as well as for diagnostics of performance and monitoring of the software after deployment. The LogServer Monitor provides a graphical user interface for the display and management of logged information from a distributed environment.

This thesis assesses the potential of using computer simulation to aid existing lean manufacturing training methods such as lecture and live simulation. An investigation of this possibility was carried out in conjunction with UMEP's Lean 101 class. In the study, two experimental computer simulation models demonstrating the push and pull production scenarios were constructed using ProModel software. Simulation models were equipped with a Visual Basic interface to aid trainees to manipulate the model via ActiveX. Constructed computer simulation was compared with live simulation to answer these research questions: 1. Was computer simulation able to teach additional lean concepts not covered in live simulations? 2. Was training time less for trainees going through a computer simulation than for those going through a live simulation? 3. Was a computer simulation quicker and easier to set up than a live simulation for trainers? 4. Did computer simulation achieve comparable educational objectives as live simulation? Objective measurements for first three questions were positive and conclusive. For the fourth one, a survey was conducted among trainees of a treatment group (computer simulation only) and a control group (live simulation only) to collect responses. Statistical analysis of the subjective responses indicated the computer simulation aided the trainees to learn and implement lean manufacturing, but was not as effective as live simulation. Holistically, these results did not warrant the complete changeover from live simulation to computer simulation. Yet, a combined implementation of computer simulation and live simulation was proposed to reap the benefits from the best of both approaches.

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