Thesis (Ph.D.)--University of Melbourne, Dept. of Geomatics, 2009. / Typescript. Includes bibliographical references (leaves 127-134)

Thesis (Ph. D.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains xvi, 425 p. : ill. (some col.), maps (part col.). Vita. Includes abstract. Includes bibliographical references (p. 316-339).

The landscape of world migration involves multiple interacting movements of people at various geographic scales, posing significant challenges to the dyadic-independence assumption underlying standard migration models. To account for emerging patterns of multilateral migration relationships, we represent world migration as a time-evolving, spatial network. The nodes in the World Migration Network (WMN) are countries located in geographic space, and the edges represent migratory movements for each decade from 1960-2000. In the first part of the thesis, we characterise the spatial network structure of the WMN, with a particular focus on detecting and mapping mesoscopic structures called 'communities' (i.e., sets of countries with denser migration connections internally than to the rest of the WMN). We employ a method for community detection that simultaneously accounts for multilateral migration, spatial constraints, time-dependence, and directionality in the WMN. We then introduce an approach for characterising local (intracommunity) and global (intercommunity) connectivity in the WMN. On this basis, we define a threefold typology that distinguishes 'cave', 'bi-regional', and 'bridging' communities. These are characterised with distinct migration patterns, spatial network structures, and temporal dynamics: cave communities are tightly-knit enduring structures that channel local migration between contiguous countries; bi-regional communities merge migration between two distinct geographic regions; bridging communities have hub-and-spoke dynamic structures that emerge from globe-spanning movements. Our results suggest that the WMN is neither a globally interconnected network nor reproducing geographic boundaries but involves heterogeneous patterns of global and local ('glocal') migration connectivity. We examine a set of relational, homophily, and spatial mechanisms that could have possibly generated the 'glocal' structure we observe. We found that communities of different types arise from significantly different mechanisms. Our results suggest that migration communities can have important implications for world migration, as different types of community structure provide distinct opportunities and constraints, thereby distinctively shaping future migration patterns.

The aim of this study is to examine key implementation and managerial issues surrounding the use of a Geographic Information Systems (GIS) as a Decisions Support Tool (DST) for planning and managing development interventions. Ever since the emergence of GIS as a powerful analytical tool in almost all spheres of human endeavour, many organisations involved in development work have adopted its use. But the challenges of conceiving and implementing a GIS in ways that are more responsive to the problems that trigger its purchase remains a daunting task to many development organisations; even those with a wealth of experience in GIS. This is one of the motivating factors for this study. In this research, some relevant themes in GIS implementation and GIS management as a Spatial Decision Support System (SDSS) were examined in the literature review. A case study research strategy was used focusing on the experience of the Nelson Mandela Bay Municipality Enterprise GIS (EGIS). The study examined how the system is been ran and what other development organisations can learn from this experience. Data was collected and analysed using a mixed research methods approach. The findings show a good level of GIS acceptance among municipality staff. However, running the system is not hitch free. A couple of problems and challenges were identified on the field. It is recommended that the municipality like most development organisations seeking GIS solutions should put the user at the centre of every technical innovation in GIS as a DST.

A 2-yr grazing study quantified pasture and animal responses of four forage systems (FS) grazed at two stocking rates (SR; 3 or 6 animals ha-1). Using „Marshall? annual ryegrass (Lolium multiflorum Lam.) and „Durana? white clover (Trifolium repens L.), FS treatments included spatially separated grass and legumes within the same paddock (SS), monoculture grass (MG), monoculture legume (ML), and a binary grass and legume mixture (MIX). Annual herbage mass (HM) was similar among FS at high SR (1900 kg ha-1), but at low SR, grass plots had greater HM (2900 vs. 2000 kg ha-1) than plots of legume monocultures. Animals on SS (1.12 kg) had greater average daily gain (ADG) than ML (0.97 kg), but neither was different from MG (1.08 kg) or MIX (1.00 kg). Low SR animals had greater ADG than high SR (1.09 vs. 0.99 kg). These results indicate that SS grazing system can improve pasture productivity.

This thesis presents the concept, development, and use of PriSM (Postprocessing of Spatial Mechanisms), an interactive 3-D graphical postprocessor for spatial mechanism synthesis and design programs. This device-independent system provides visualization, modeling, and animation of spatial mechanisms. New ideas and methods are described to simplify the interactive specification of scene rendering and color parameters using the international ISO standard for 3-D graphics, PHIGS (Programmer’s Hierarchical Interactive Graphic System), and its proposed extensions, PHIGS+. Perception and evaluation of spatial mechanism designs are significantly improved by the use of PHIGS+ functionality to produce animated models that are shaded, lighted, and depth cued. Examples are presented for the rendering and animation of spatial mechanisms on a Raster Technologies (Alliant) GX4000 workstation with a hardware-based PHIGS+ graphics subsystem, UNIX, NeWS, and C. In addition to color photographs and grayscale bitmaps of the PriSM implementation, the program structure and source code listing are fully documented. / Master of Science

Recent efforts in computer aided design and computer aided manufacturing have stressed the development of robotics. However, there are many applications where a spatial mechanism could be used in place of a robot, but the mechanism design theory has not been fully developed. This thesis presents the fundamentals of a computer aided design system for the RSCR (revolute-spheric-cylindric-revolute) spatial mechanism. Exact relationships for position, velocity, and acceleration analysis have been derived. Closed form synthesis equations have been developed for the RS and RC dyads. The theory developed in this thesis has been implemented on the digital computer in the form of a FORTRAN77 computer program. This computer implementation includes interfaces with MECHIN, a graphical preprocessor for spatial mechanism synthesis and analysis, and GENMOD, an automatic model generator for spatial mechanisms. / Master of Science

Dissertation (PhD)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: Municipal water distribution maintenance is very important for sustainable urban development. Water pipe breaks result not only in a disruption in service but also in significant loss of water, which otherwise could have been sold to the consumer. In countries where water is scarce, such as South Africa, water losses can be detrimental to the living standard of people. Water pipe breaks can furthermore cause extensive damage to nearby lower-lying properties. Existing decision support systems available in the field of water distribution system maintenance are mainly focused on leak detection and pipe rehabilitation/replacement strategy. These existing systems, however, do not address the actual causes of pipe breaks and pipe break impact is also not supported. The aim of this research is to develop a spatial decision support system (SDSS) for pipe break susceptibility analysis and impact assessment. The engineer (or public works administrator) can apply the SDSS to model the complex pipe break phenomena in the municipal water distribution system. The SDSS can identify pipes susceptible to breaking and pipes with potentially high break impact as far as water loss and damage caused to nearby property are concerned. This combined pipe break susceptibility analysis and potential impact assessment should promote more informed decision-making on preventative maintenance measures to be taken and their prioritisation. The dissertation consists offive parts. In the first part (Chapters 1-4) theories on information systems, fuzzy logic, object-oriented modelling, Unified Modelling Language (UML) and pipe break causes are presented. This literature review provides a basis on which the SDSS for pipe break susceptibility analysis and impact assessment can be developed. In the second part (Chapter 5) the general user requirements and design of the SDSS are given. The general SDSS architecture, the general system functionality and the user interface are described and designed in this part of the dissertation. The third part (Chapter 6) provides the detailed user requirements and design of the subsystems of the SDSS. Specialised functionality for pipe break susceptibility analysis and impact assessment is added to the general design of the SDSS. Subsystems are designed for analysing the pipe break susceptibility due to age, air-pocket formation and tree-root attack. Pipe break impact assessment subsystems are also designed for assessing water loss and potential damage caused to nearby property. Finally, a combined analysis subsystem is designed for combined pipe break susceptibility analysis and impact assessment. In the fourth part (Chapter 7), the SDSS is applied to the water distribution system of the Paarl Municipality to identify pipes in the network that have both high break susceptibility and also high break impact. The pipe break susceptibility analysis model of the SDSS is also tested and calibrated by comparing the model results with actual pipe break occurrence data of the study area. The final chapter (Chapter 8) contains the summary and recommendations regarding the functionality of the newly developed SDSS. / AFRIKAANSE OPSOMMING: Die instandhouding van munisipale waterverspreidingstelsels is uiters belangrik vir volhoubare stedelike ontwikkeling. Waterpypbreuke lei nie alleenlik tot onderbreking in diensverskaffing nie, maar ook tot beduidende waterverlies en verlies aan inkomste uit waterverkope. In lande waar water skaars is, soos in Suid-Afrika, kan waterverliese die lewenstandaard van die bevolking nadelig beïnvloed. Waterpypbreuke kan ook groot skade aan naby-geleë laag-liggende eiendomme aanrig. Besluitnemingstelsels tans beskikbaar op die gebied van instandhouding van waterverspreidingstelsels is hoofsaaklik gerig op lekkasie-opsporing en pyprehabilitasie- en pypvervangingstrategieë. Hierdie bestaande stelsels spreek egter nie die eintlike oorsake van pypbreuke aan nie, daar word ook nie op die impak van pypbreuke ingegaan nie. Die doelwit van hierdie navorsing is om 'n ruimtelike besluitnemingstelsel (RBS) - vir pypbreuk-risiko-analise en impakberaming te ontwikkel. Die ingenieur (of stelselbestuurder) kan met behulp van die RBS die komplekse pypbreukverskynsel in 'n munisipale waterverspreidingstelsel modelleer. Die RBS kan pype met hoë breek-potensiaal identifiseer asook pype wat, indien dit breek, groot waterverlies of skade aan naby-geleë eiendomme sal veroorsaak. Hierdie gekombineerde pypbreuk-risiko-analise en impakberaming behoort meer oordeelkundige besluitneming te bevorder deur beter prioritisering van voorkomende instandhoudingsmaatreëls en die uitvoering daarvan. Die proefskrif bestaan uit vyf dele. In die eerste deel (Hoofstukke 1-4) word die teorieë oor inligtingstelsels, 'fuzzy logic', objek-georiënteerde modellering, 'unified modelling language (UML)' en die oorsake van pypbreuke behandel. Hierdie literatuurstudie skep die basis waaruit die RBS vir pypbreukrisikobepaling en impakberaming ontwikkel sal word. In die tweede deel (Hoofstuk 5) word die algemene gebruikersbehoeftes en die ontwerp van die RBS uiteengesit. Die algemene RBS struktuur en die gebruikerskoppelvlak word in hierdie deel van die proefskrif beskryf en ontwerp. In die derde deel (Hoofstuk 6) word die gedetailleerde gebruikersbehoeftes en die ontwerp van die substelsels van die RBS uiteengesit. Gespesialiseerde funksionaliteit vir pypbreuk-risikobepaling en impakberaming is tot die algemene ontwerp van die RBS bygevoeg. Substelsels is ontwerp vir die ontleding van pypbreuk-risiko as gevolg van ouderdom, lugblaas-vorming en boomwortelaanval. Substelsels vir impakberaming is ook ontwerp om waterverlies en potensiële skade aan eiendomme vas te stel. Ten slotte word 'n gekombineerde ontledingsubstelsel vir gekombineerde pypbreuk-risikobepaling en impakberaming opgestel. In die vierde deel (Hoofstuk 7) word die RBS toegepas op die waterverspreidingstelsel van die Paarlse munisipaliteit om pype uit te ken wat beide 'n hoë breuk-risiko en 'n hoë breuk-impak bevat. Die pypbreuk-analise model van die RBS is ook getoets en gekalibreer deur die resultate van die model te vergelyk met data van werklike pypbreuke in die studiegebied. Die laaste hoofstuk (Hoofstuk 8) bevat die samevatting en die aanbevelings rakende die funksionaliteit van die voorgestelde RBS.

Les lanceurs spatiaux actuels, et en particulier Ariane 5, utilisent le réseau déterministe MIL-STD-1553B. Compte tenu des nouveaux objectifs de réduction des coûts et de la masse du système global ainsi que du support de trafic de télémesure multimédia, cette technologie n'est plus forcément optimale. Parmi les différents candidats de remplacement, cette thèse met en évidence les capacités du standard Ethernet à répondre à ces nouveaux objectifs tout en s'appuyant sur une utilisation de composants matériels et d'outils de développement existants à moindre coût (COTS). La première contribution porte sur l'évaluation de performances temporelles des architectures commutées. Les travaux mettent ainsi en évidence les gains et limites liés au choix d'une part du mode de communication (de maître/esclaves à producteurs/consommateur) et d'autre part à une future distribution de l'avionique. Pour cela, cette étude s'appuie sur une évaluation déterministe des délais de bout en bout par calcul réseau, simulations et expérimentations. Ces résultats ont été validés pour deux architectures commutées pour un scénario représentatif des vols actuels. La seconde contribution concerne l'amélioration de la disponibilité du système de communication. Il est proposé une stratégie de reconfiguration "temps réel" des chemins par supervision active du réseau. Dans le cadre d'exigences critiques, il est également proposé l'utilisation d'arbres couvrants multiples permettant d'anticiper la défaillance d'éléments d'interconnexion. Enfin, le choix d'architectures commutées et segmentées ne permet plus d'observer en tout point le réseau comme sur un bus. Pour cela, cette thèse met en avant les conditions et performances dans lesquelles un protocole de synchronisation d'horloges pourra contribuer à générer à partir de plusieurs points de captures une trace unique des échanges sur le réseau. Ce travail permettra d'identifier les tests pour une future validation du standard Ethernet pour les lanceurs spatiaux / Current space launchers, and particularly Ariane 5, use the deterministic network MIL-STD-1553B. According to the new objectives of cost and system mass reduction and of multimedia traffic support, this technology is not optimal anymore. Among the potential candidates, this thesis highlights the fact that such objectives can be achieved through the use of Ethernet standard based on components-on-the-shelf. The first contribution focuses on time performance evaluation of switched architectures. The gain and limits related to the communication mode (from master/slaves to producers/consummers) and future avionic distribution are studied. This study relies on a deterministic evaluation of the end-to-end delay by using network calculus, simulations and experiments. These results are validated with two switched architectures by using a scenario considered as representative of current flights. The second contribution is the network availability improvement. A real-time path reconfiguration strategy is proposed through active network supervision. Based on critical requirements, it is also suggested to use multiple spanning-trees for anticipating network element failures. The last contribution deals with the issue that in switched and segmented architectures it is not possible to collect all the traffic as in a bus. In order to do so, this thesis introduces the configurations under which a clock synchronization protocol could contribute to generate a single network trace from many collecting points. This work will enable to identify the tests for a future Ethernet standard validation in the framework of space launchers

This dissertation investigates department stores as complex spatial and cultural buildings, in which values and ideas are expressed, negotiated, and produced. Situated in a cultural context commonly referred to as a society of consumption, where identity and social structures are worked out through consumption rather than production, the query turns to a specific act of consumption: that of shopping. More precisely, it investigates the role of space and spatial distribution in shopping. How space is distributed, arranged, or ordered allows for different possibilities in constructing categories from which the shoppers are to make a selection, and for how these categories can be related to one another, which informs the shoppers what belongs together, what is to be held apart, what is important, what is private, what is public, and what is of higher or lower status. It further supports, prevents, and promotes different routes and choices, giving different patterns of presence, publicity, privacy, purpose, etc. that not only affects the atmosphere of the spaces, but makes suggestions of what is found in them. These questions are investigated through a series of conceptual laboratories, each addressing the problem from different standpoints and focusing on different parts of the question: from how categories are constructed and given character, to how they form systems of values, how shoppers are trained in aesthetics of fashion, how relative degrees of presences are made use of, and how they appear influenced by spatial distribution. In this, the work shifts between qualitative and quantitative methods, each completing and evolving the other. It shows that to a remarkable degree, much of the emergent values and ideas can be understood through the filter of spatial configurations, and especially when treated as two systems: one of exposure and one of availability. As similar operations also affect patterns of movement and being, which enables them to also be related to publicity, privacy, and other social characters, the department stores can be understood as not only commercial spaces but as sites of negotiation of public culture. As such, both the analytic model and the more specific findings have important implications for architectural theory in general. / QC 20100803