Thesis (MSc (Geography and Environmental Studies))--University of Stellenbosch, 2005. / 81 Leaves printed on single pages i-xi, preliminary pages and numbered pages 1- 70. Includes bibliography, list of tables and list of figures. / Digitized at 300 dpi color PDF format (OCR), using KODAK i 1220 PLUS scanner. / ENGLISH ABSTRACT: Geological field mapping is often limited by logistical and cost constraints as well as the scope and extent of observations possible using ground-based mapping. Remote sensing offers, among others, the advantages of an increased spectral range for observations and a regional perspective of areas under observation. This study aimed to determine the accuracy of a collection of image classification techniques when applied to ASTER reflectance data. Band rationing, the Crosta Technique, Constrained Energy Minimization, Spectral Correlation Mapping and the Maximum Likelihood Classifier were evaluated for their efficiency in detecting and discriminating between greenstone and granitoid material. The study area was the Archaean Barberton Greenstone Belt in the eastern Mpumalanga Province, South Africa. ASTER reflectance imagery was acquired and pre-processed. Training and reference data was extracted from the image through visual inspection and expert knowledge. The training data was used in conjunction with USGS mineral spectra to train the five classification algorithms using the ERDAS's software package. This resulted in abundance images for the target materials specified by the training data. The Maximum Likelihood Classifier produced a classified thematic map. The reference data was used to perform a rigorous classification accuracy assessment procedure. All abundance images were thresholded to varying levels, obtaining accuracy statistics at every level. In so doing, threshold levels could be defined for every abundance image in such a way that the reliability of the classification was optimized. For each abundance image, as well as for the output map of the Maximum Likelihood Classifier, user's- and producer's accuracies as well as kappa statistics were derived and used as comparative measures of efficiency between the five techniques. This information was also used to assess the spectral separability of the target materials. The Maximum Likelihood Classifier outperformed the other techniques significantly, achieving an overall classification accuracy of 81.1% and an overall kappa value of 0.748. Greenstone rocks were accurately discriminated from granitoid rocks with accuracies between 72.9% and 98.5%, while granitoid rocks showed very poor ability to be accurately distinguished from each other. The main recommendations from this study are that thermal infrared and gamma-ray data be considered, together with better vegetation masking and an investigation into object orientated techniques. / AFRIKAANSE OPSOMMING: Geologiese veldkartering word algemeen beperk deur logistiese en koste-verwante faktore, sowel as die beperkte bestek waartoe waarnemings met veld-gebasseerde tegnieke gemaak kan word. Afstandswaarneming bied, onder andere, 'n vergrote spekrale omvang vir waarnemings en 'n regionale perspektief van die area wat bestudeer word. Hierdie studie was gemik daarop om die akkuraatheid van 'n versameling beeld-klassifikasie tegnieke, toegepas op ASTER data, te bepaal. Bandverhoudings, die Crosta Tegniek, "Constrained Energy Minimization", Spektrale Korrellasie Kartering, en Maksimum Waarskynlikheid Klassifikasie is evalueer op grond van hul vermoë om groensteen en granitoied-rotse op te spoor en tussen hulle te onderskei. Die studiegebied was die Argalese Barberton Groensteengordel in die oostelike Mpumalanga Provinsie in Suid Afrika. 'n ASTER refleksie beeld is verkry, waarop voorverwerking uitgevoer is. Opleidings- en verwysingsdata is van die beeld verkry deur visuele inspeksie en vakkundige kennis. Die opleidingsdata is saam met VSGO mineraalspektra gebruik om die vyf klassifikasie algoritmes met behulp van die ERDAS sagteware pakket op te lei. Die resultaat was volopheidsbeelde vir die teikenmateriale gespesifiseer in die opleidingsdata. Die Maksimum Waarskynlikheid algoritme het 'n geklassifiseerde tematiese beeld gelewer. Met behulp van die verwysingsdata is 'n streng akkuraatheidstoetsing prosedure uitgevoer. Vir alle volopheidsbeelde is 'n reeks drempelwaardes gestel, en by elke drempelwaarde is akkuraatheidsstatistieke afgelei. Op hierdie manier kon 'n drempelwaarde vir elke volopheidsbeeld vasgestel word sodat die drempelwaarde die betroubaarheid van die klassifikasie optimeer. Vir elke volopheidsbeeld, asook vir die tematiese kaart verkry van die Maksimum Waarskynlikheid klassifikasie, is gebruikers- en produsent-akkuraathede en kappa statistieke bereken. Hierdie waardes is gebruik as vergelykende maatstawwe van akkuraatheid tussen die vyf tegnieke, asook van die spektrale skeibaarheid van die onderskeie teikenmateriale. Die Maksimum Waarskynlikheid klassifikasie het die beste resultate gelewer, met 'n algehele klassifikasie akkuraatheid van 81.1%, en 'n gemiddelde kappa waarde van 0.748. Groensteenrotse kon met hoë akkuraathede van tussen 72.9% en 98.5% van granitoiedrotse onderskei word, terwyl granitoiedrotse 'n swak vermoë getoon het om van mekaar onderskei te word. Die belangrikste aanbevelings vanuit hierdie studie is dat termiese uitstralingdata asook gamma-straal data geimplimenteer word. Beter verwydering van plantegroei en 'n studie na die lewensvatbaarheid van objekgeorienteerde metodes word ook aanbeveel.

Orientadores: Maria Cecilia Calani Baranauskas, Claudia Maria Bauzer Medeiros / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-07T08:38:34Z (GMT). No. of bitstreams: 1 Schimiguel_Juliano_D.pdf: 17588489 bytes, checksum: 9550a21b1f40b24668f4ab2d6d270dda (MD5) Previous issue date: 2006 / Resumo: Sistemas de Informação Geográfica (SIG) são categorias de software que permitem a manipulação, gerenciamento e visualização de dados geo referenciados. O termo georeferenciado denota associação a um sistema de coordenadas geográficas. Existem inúmeras categorias de aplicações SIG. em diferentes escalas e domínios, abrangendo desde temas urbanos até ambientais. Aplicações de Sistemas de Informação Geográfica na Web, neste trabalho denominadas "aplicações SIG Web", são sistemas onde a 'informação geográfica' pode estar dispersa em diferentes locais e sua manipulação via SIG ocorre através da Internet. A importância de SIG Web direcionados a sistemas agrícolas, foco deste trabalho, advém do fato de funcionarem como um ferramental útil para usuários que trabalham direta ou indiretamente no domínio: agricultores, agrônomos, cooperativas agrícolas, órgãos governamentais ligados à área. Interfaces de Usuário em SIG Web têm sido desenvolvidas sem o uso de práticas e critérios que considerem especificidades desse domínio de aplicação e a diversidade de usuários na web. A qualidade da interface dessas aplicações influencia diretamente o seu uso. Este trabalho se propõe a conceituar qualidade no contexto de interfaces de aplicações SIG Web. investigando tanto o produto - a interface de aplicações SIG Web - quanto o processo de design de interfaces de tais aplicações. Estas duas perspectivas formam a base de recomendações para a avaliação de suas interfaces de aplicações. O resultado principal do trabalho é a definição de um framework de bases semióticas para orientar designers e partes interessadas no design de aplicações SIG Web na avaliação de interfaces de tais aplicações. Esse framework organiza um espaço de análise que contém as recomendações identificadas nos contextos de avaliação do produto e de processo de design de aplicações SIG Web. Ele foi desenvolvido e testado utilizando um conjunto de aplicações e estudos de caso reais, no domínio agrícola. / Abstract: Geographic Information Systems (GIS) are pieces of software that allow manipulation, management and visualization of georeferenced data, where the term "georeferencing" denotes association with geographic coordinates. There are countless kinds of applications that use GIS, for different domains and using distinct geographic scales, ranging from urban to environmental issues. This thesis uses the expression "Web GIS applications" to denote applications running on Geographic Information Systems. They are systems where the geographic information may be distributed over several sites, and is manipulated by users on the Internet, using a GIS. This work is centered on Web GIS applications for the agricultural domain. The relevance of these applications is based on the fact that they serve as a basic decision platform for users that directly or indirectly work in this domain: farmers, agronomers, cooperatives or government instances. Web GIS User Interfaces have long been developed without considering practices and criteria that take into account the domain's specificity, or the wide spectrum of Web users. The quality of these interfaces has a major impact in the use of these applications. This thesis is centered on analyzing the issue of the quality of Web GIS application interfaces, under two perspectives: the product - the interface itself: and the design process of these interfaces. The main contribution of this work is a definition of a framework based on semiotics that guides Web GIS application designers in the evaluation of the interfaces of these applications. This framework includes a set of procedures, as well as a set of recommendations to be followed by designers in order to improve interface quality. The framework was developed and validated using several real life applications, for the agricultural domain. / Doutorado / Sistemas de Informação / Doutor em Ciência da Computação

This thesis explores the problem of information systems evaluation by conceptualising it as a process in which the manager comes to an understanding about a system. In other words, information systems evaluation is a hermeneutic process. The thesis explicates this notion through an argument that is itself hermeneutic in its development, beginning with the mainstream functionalist view of information systems evaluation, and then considering an interpretive view of IS evaluation, each of which points to one of two stereotypes of IS evaluation and the manager engaged in this process: the objective/rational manager utilising objective/rational methods versus the subjective/political manager engaged in political manoeuvring, utilising objective/rational methods only as ritual or symbolism. Neither of these opposing stereotypes is satisfactory. Instead, this thesis proposes a dialectic view of information systems evaluation, in terms of which, rather than being a decision maker, the manager is in-the-world, evaluating systems in order to get the job done, on the basis of her thrownness in-the-world. This conceptualisation provides an intuitively appropriate account of evaluation on the part of an individual manager, but we must still consider how managers as members of the organisation, reach a common understanding about a system. This they do through a process of organisational learning as encultured knowing, in terms of which a narrative, situated, pragmatic knowledge is most useful in evaluation. Evaluation, in other words, happens in the course of skilful conversation. Such conversation is, however, not always skilful because the organisation is not just a collection of individuals but also a network of power relations. Conversations as generators of meaning are never held outside of power: systems evaluations as conversations cannot take place outside of a regime of truth. A post-dualist view of action as both constituted by and constituting structure, however, suggests that there is always the potential for genuinely hermeneutic and ethical conversation, provided it is both improvisatory and deconstructive. Having understood the requirement for improvisation and deconstruction, it is possible to suggest some heuristics for information systems evaluation based on these ideas. / Dissertation (Phd (Information Technology))--University of Pretoria, 2003. / Informatics / unrestricted

The merger of institutions of higher learning in South Africa has demonstrated to the study an exploration of the role of strategic internal communication system – in the merging of the Walter Sisulu University. The purpose of the study is to determine to what extent employees of the Walter Sisulu University have perceived that the internal communication system of this university has contributed towards an effectively merged organisation. The study was conducted after three historically disadvantaged institutions of higher learning merged to form one comprehensive university. The three merged institutions are: the Border Technikon, the Eastern Cape Technikon and the University of Transkei. It was foreseeable during the process of the merger, that combining three institutions could possibly result in lower staff morale and uncertainty. The study has explored the theoretical framework for understanding the role of strategic internal communication systems in an organisation. The study was approached from a systems' perspective and that of a transformational model. A survey research design was utilised for the purpose of this study – in order to assess the validity and reliability of the data. A qualitative research design was used for the purpose of this study – in order to acquire the desired outcomes of the research. Questionnaires were used and the sample was drawn from a large population of the Walter Sisulu University – from, four campuses – with the aim of allowing one to make inferences about the population as a whole. The questionnaire was structured in four main sections namely: Biographical information, internal-communication systems, tools of internal communication, and line-management communication. The findings of the study aids the understanding behind the view of internal communication systems as having contributed – or not contributed – to a successfully merged university.

In recent years, the focus of cartographic research has shifted from the cartographic communication paradigm to the scientific visualization paradigm. With this, there has been a resurgence of cognitive research that is invaluable in guiding the design and evaluation of effective cartographic visualization tools. The design of new tools that allow effective visual exploration of spatial data and data quality information in a resource management setting is critical if decision-makers and policy setters are to make accurate and confident decisions that will have a positive long-term impact on the environment. The research presented in this dissertation integrates the results of previous research in spatial cognition, visualization of spatial information and on-line map use in order to explore the design, development and experimental testing of four interactive visualization tools that can be used to simultaneously explore spatial data and data quality. Two are traditional online tools (side-by-side and sequenced maps) and two are newly developed tools (an interactive "merger" bivariate map and a hybrid o f the merger map and the hypermap). The key research question is: Are interactive visualization tools, such as interactive bivariate maps and hypermaps, more effective for communicating spatial information than less interactive tools such as sequenced maps? A methodology was developed in which subjects used the visualization tools to explore a forest species composition and associated data quality map in order to perform a range of map-use tasks. Tasks focused on an imaginary land-use conflict for a small region of mixed boreal forest in Northern Alberta. Subject responses in terms of performance (accuracy and confidence) and preference are recorded and analyzed. Results show that theory-based, well-designed interactive tools facilitate improved performance across all tasks, but there is an optimal matching between specific tasks and tools. The results are generalized into practical guidelines for software developers. The use of confidence as a measure of map-use effectiveness is verified. In this experimental setting, individual differences (in terms of preference, ability, gender etc.) did not significantly affect performance. / Arts, Faculty of / Geography, Department of / Graduate

The purpose of this study is to create the prototype expert system, HEES, and to examine its usability and usefulness in evaluating hypertext software.

Hybrid systems for analyzing big data integrate an analytic tool and a dedicated data-management platform, storing data and operating on the data at both components. While hybrid systems have benefits over alternative architectures, in order to be effective, data movement between the two hybrid components must be minimized. Extant hybrid systems either fail to address performance problems stemming from inter-component data movement, or else require the user to explicitly reason about and manage data movement. My work presents the design, implementation, and evaluation of a hybrid analytic system for array-structured data that automatically minimizes data movement between the hybrid components. The proposed research first motivates the need for automatic data-movement minimization in hybrid systems, demonstrating that under workloads whose inputs vary in size, shape, and location, automation is the only practical way to reduce data movement. I then present a prototype hybrid system that automatically minimizes data movement. The exposition includes salient contributions to the research area, including a partial semantic mapping between hybrid components, the adaptation of rewrite-based query transformation techniques to minimize data movement in array-modeled hybrid systems, and empirical evaluation of the approach's utility. Experimental results not only illustrate the hybrid system's overall effectiveness in minimizing data movement, but also illuminate contributions made by various elements of the design.

This thesis proposes a design of a rapidly deployable cellular network prototype that provides voice and data communications and it is interoperable with legacy devices and the existing network infrastructure. The prototype is based on software defined radio and makes use of IEEE 802.11 unlicensed wireless radio frequency (RF) band for backhaul link and an open source GSM implementation software. The prototype is also evaluated in environments where there is limited control of the radio frequency landscape, and using Voice Over Internet Protocol (VoIP) performance metrics to measure the quality of service. It is observed that in environments where the IEEE 802.11 band is not heavily utilized, a large number of calls are supported with good quality of service. However, when this band is heavily utilized only a few calls can be supported as the quality of service rapidly degrades with increasing number of calls, which is due to interference. It is concluded that in order to achieve tolerable voice quality, unused licensed spectrum is needed for backhaul communication between base stations.

This project developed a process for developing and evaluating enhancements to the American Red Cross’ disaster communication system. The stimulus for this project was a statement from the American Red Cross Disaster Service staff that the present communication system was unable to meet their needs. Some proposals for altering the present system were available, but there was no established means to identify the merits and drawbacks of these proposals. A principal feature of the proposed development process is a methodology to evaluate the impact, benefit, and cost of proposed enhancements. This methodology can be used to evaluate any proposed change to the disaster communication system. The process and methodology which have been developed are adaptations of accepted systems engineering tools such as the Life Cycle, mission scenarios, and models. / Master of Science

If knowledge has been gathered by the practitioners’ community in the area of health data warehousing evaluation, it is mostly relying on anecdotal evidence instead of academic research. Isolated dimensions have received more attention and benefit from definitions and performance measures. However, very few cases can be found in the literature which describe how the assessment of the technology can be made, and these cases do not provide insight on how to systematize such assessment. The research in this dissertation is aimed at bridging this knowledge gap by developing an evaluation framework, and conducting an empirical study to further investigate the state of health data warehousing evaluation and the use of the technology to improve healthcare efficiency, as well as to compare these findings with the proposed framework. The empirical study involved an exploratory approach and used a qualitative method, i.e. audio-taped semi-structured interviews. The interviews were conducted in collaboration with the Healthcare Data Warehousing Association and involved 21 participants who were members of the Association working in a mid- to upper-level management capacity on the development and implementation of health data warehousing. All audio-taped interviews were transcribed and transcripts were coded using a qualitative analysis software package (NVivo, QSR International). Results were obtained in three areas. First, the study established that current health data warehousing systems are typically not formally evaluated. Systematic assessments relying on predetermined indicators and commonly accepted evaluation methods are very seldom performed and Critical Success Factors are not used as a reference to guide the system’s evaluation. This finding appears to explain why a literature review on the topic returns so few publications. Second, from patient throughput to productivity tracking and cost optimization, the study provided evidence of the contribution of data warehousing to the improvement of healthcare systems’ efficiency. Multiple examples were given by participants to illustrate the ways in which the technology contributed to streamlining the care process and increase healthcare efficiency in their respective organizations. Third, the study compared the proposed framework with current practices. Because formal evaluations were seldom performed, the empirical study offered limited feedback on the framework’s structure and rather informed its content and the assessment factors initially defined. / Graduate