Dissertations / Theses on the topic 'Spatial systems'
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Davies, Jessica. "Expanding the spatial data infrastructure model to support spatial wireless applications /." Connect to thesis, 2003. http://eprints.unimelb.edu.au/archive/00001044.
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Jusoh, Shaidah. "Integrating stand-alone Web-based spatial information systems into integrated spatial information system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ33236.pdf.
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Sandhu, Raghbir Singh. "Intelligent spatial decision support systems." Thesis, University College London (University of London), 1998. http://discovery.ucl.ac.uk/1317911/.
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This thesis investigates the conceptual and methodological issues for the development of Intelligent Spatial Decision Support Systems (ISDSS). These are spatial decision support systems (SDSS) integrating intelligent systems techniques (Genetic Algorithms, Neural Networks, Expert Systems, Fuzzy Logic and Nonlinear methods) with traditional modelling and statistical methods for the analysis of spatial problems. The principal aim of this work is to verify the feasibility of heterogeneous systems for spatial decision support derived from a combination of traditional numerical techniques and intelligent techniques in order to provide superior performance and functionality to that achieved through the use of traditional methods alone. This thesis is composed of four distinct sections: (i) a taxonomy covering the employment of intelligent systems techniques in specific applications of geographical information systems and SDSS; (ii) the development of a prototype ISDSS; (iii) application of the prototype ISDSS to modelling the spatiotemporal dynamics of high technology industry in the South-East of England; and (iv) the development of ISDSS architectures utilising interapplication communication techniques. Existing approaches for implementing modelling tools within SDSS and GIS generally fall into one of two schemes - loose coupling or tight coupling - both of which involve a tradeoff between generality and speed of data interchange. In addition, these schemes offer little use of distributed processing resources. A prototype ISDSS was developed in collaboration with KPMG Peat Marwick's High Technology Practice as a general purpose spatiotemporal analysis tool with particular regard to modelling high technology industry. The GeoAnalyser system furnishes the user with animation and time plotting tools for observing spatiotemporal dynamics; such tools are typically not found in existing SDSS or GIS. Furthermore, GeoAnalyser employs the client/server model of distributed computing to link the front end client application with the back end modelling component contained within the server application. GeoAnalyser demonstrates a hybrid approach to spatial problem solving - the application utilises a nonlinear model for the temporal evolution of spatial variables and a genetic algorithm for calibrating the model in order to establish a good fit for the dataset under investigation. Several novel architectures are proposed for ISDSS based on existing distributed systems technologies. These architectures are assessed in terms of user interface, data and functional integration. Implementation issues are also discussed. The research contributions of this work are four-fold: (i) it lays the foundation for ISDSS as a distinct type of system for spatial decision support by examining the user interface, performance and methodological requirements of such systems; (ii) it explores a new approach for linking modelling techniques and SDSS; (iii) it investigates the possibility of modelling high technology industry; and (iv) it details novel architectures for ISDSS based on distributed systems.
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El-Geresy, Baher. "Qualitative representation and reasoning for spatial and spatio-temporal systems." Thesis, University of South Wales, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403330.
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Alkhaldi, Rawan. "Spatial data transmission security authentication of spatial data using a new temporal taxonomy /." abstract and full text PDF (free order & download UNR users only), 2005. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1433280.
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Hope, Susannah Jayne. "Decision making under spatial uncertainty /." Connect to thesis, 2005. http://repository.unimelb.edu.au/10187/1150.
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Errors are inherent to all spatial datasets and give rise to a level of uncertainty in the final product of a geographic information system (GIS). There is growing recognition that the uncertainty associated with spatial information should be represented to users in a comprehensive and unambiguous way. However, the effects on decision-making of such representations have not been thoroughly investigated. Studies from the psychological literature indicate decision-making biases when information is uncertain. This study explores the effects of representing spatial uncertainty, through an examination of how decision-making may be affected by the introduction of thematic uncertainty and an investigation of the effects of different representations of positional uncertainty on decision-making.Two case studies are presented. The first of these considers the effects on decision-making of including thematic uncertainty information within the context of an airport siting decision task. An extremely significant tendency to select a zone for which the thematic classification is known to be of high certainty was observed. The reluctance to select a zone for which the thematic classification is of low certainty was strong enough to sometimes lead to decision-making that can only be described as irrational.
The second case study investigates how decision-making may be affected by different representations of positional uncertainty within the context of maritime navigation. The same uncertainty information was presented to participants using four different display methods. Significant differences in their decisions were observed. Strong preferences for certain display methods were also exhibited, with some representations being ranked significantly higher than others.
The findings from these preliminary studies demonstrate that the inclusion of uncertainty information does influence decision-making but does not necessarily lead to better decisions. A bias against information of low certainty was observed, sometimes leading to the making of irrational decisions. In addition, the form of uncertainty representation itself may affect decision-making. Further research into the effects on decision-making of representing spatial uncertainty is needed before it can be assumed that the inclusion of such information will lead to more informed decisions being made.
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Vlado, Veldic. "GIS for spatial decision-making." Diss., University of Pretoria, 2001. http://hdl.handle.net/2263/29747.
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Hu, Haibo. "Spatial and continuous spatial queries on smart mobile clients /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?COMP%202005%20HU.
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Drawert, Brian J. "Spatial Stochastic Simulation of Biochemical Systems." Thesis, University of California, Santa Barbara, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3559784.
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Recent advances in biology have shown that proteins and genes often interact probabilistically. The resulting effects that arise from these stochastic dynamics differ significantly than traditional deterministic formulations, and have biologically significant ramifications. This has led to the development of computational models of the discrete stochastic biochemical pathways found in living organisms. These include spatial stochastic models, where the physical extent of the domain plays an important role; analogous to traditional partial differential equations.
Simulation of spatial stochastic models is a computationally intensive task. We have developed a new algorithm, the Diffusive Finite State Projection (DFSP) method for the efficient and accurate simulation of stochastic spatially inhomogeneous biochemical systems. DFSP makes use of a novel formulation of Finite State Projection (FSP) to simulate diffusion, while reactions are handled by the Stochastic Simulation Algorithm (SSA). Further, we adapt DFSP to three dimensional, unstructured, tetrahedral meshes in inclusion in the mature and widely usable systems biology modeling software URDME, enabling simulation of the complex geometries found in biological systems. Additionally, we extend DFSP with adaptive error control and a highly efficient parallel implementation for the graphics processing units (GPU).
In an effort to understand biological processes that exhibit stochastic dynamics, we have developed a spatial stochastic model of cellular polarization. Specifically we investigate the ability of yeast cells to sense a spatial gradient of mating pheromone and respond by forming a projection in the direction of the mating partner. Our results demonstrates that higher levels of stochastic noise results in increased robustness, giving support to a cellular model where noise and spatial heterogeneity combine to achieve robust biological function. This also highlights the importance of spatial stochastic modeling to reproduce experimental observations.
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Fischer, Manfred M., and Peter Nijkamp. "Geographic Information Systems and Spatial Analysis." WU Vienna University of Economics and Business, 1991. http://epub.wu.ac.at/4219/1/WSG_DP_1491.pdf.
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Smith, Mark. "Spatial reaction systems on parallel supercomputers." Thesis, University of Edinburgh, 1994. http://hdl.handle.net/1842/12985.
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A wide variety of physical, chemical and biological systems can be represented as a collection of discrete spatial locations within which some interaction proceeds, and between which reactants diffuse or migrate. Many such real-world spatial reaction systems are known to be both non-linear and stochastic in nature, and thus studies of these systems have generally relied upon analytic approximation and computer simulation. However, this later approach can become impractical for large, complex systems which require massive computational resources. In this work we analyse a general spatial reaction system in both the deterministic and stochastic scenarios. A study of the deterministic parameter space reveals a new categorisation for system development in terms of its criticality. This result is then coupled with a complete analysis of the linearised stochastic system, in order to provide an understanding of the spatial-temporal covariance structures within reactant distributions. In addition to an analysis, and empirical confirmation, of the various criticality behaviours in both deterministic and stochastic cases, we use our theoretical results to enable efficient implementation of spatial reaction system simulations on parallel supercomputers. Such novel computing resources are necessary to enable the study of realistic-scale, long-term stochastic activity, however they are notoriously difficult to exploit. We have therefore developed advanced programming and implementation techniques, concentrating mainly on dynamic load-balancing methodologies, to enable such studies. These techniques make direct use of our analytic results in order to achieve the most efficient exploitation of supercomputing resources, given the particular attributes of the system under study. These new techniques have allowed us to investigate complex individual-based systems on a previously untried scale. In addition, they are of general applicability to a wide range of real-world simulations.
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Holzmann, Clemens. "Spatial awareness of autonomous embedded systems." Wiesbaden Vieweg + Teubner, 2008. http://d-nb.info/992304865/04.
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Astély, David. "Spatial and spatio-temporal processing with antenna arrays in wireless systems /." Stockholm, 1999. http://www.lib.kth.se/abs99/aste0601.pdf.
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Vlado, Veldic. "GIS for spatial decision-making." Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-11242005-101724/.
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Fischer, Manfred M., and Henk J. Scholten. "Geographic Information Systems, Spatial Data Analysis and Spatial Modelling. - Problems and Possibilities -." WU Vienna University of Economics and Business, 1994. http://epub.wu.ac.at/4194/1/WSG_DP_3794.pdf.
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This article is the position paper for the ESF-GISDATA Specialist Meeting on GIS &
Spatial Analysis, Amsterdam, 1-5December1993. The focus here is on the two major
themes of the meeting: Spatial Data Analysis and Spatial Modelling. Special emphasis
is laid on specific problems and possibilities for interfacing spatial analysis tools (i.e.
spatial data analysis techniques and spatial models) and GIS. Both GIS application
fields, the environmental sciences and the social sciences, are taken into
consideration. (authors' abstract)Series: Discussion Papers of the Institute for Economic Geography and GIScience
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Oh, Inhee Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Spatial reuse in TDMA wireless networks." Publisher:University of New South Wales. Electrical Engineering & Telecommunications, 2008. http://handle.unsw.edu.au/1959.4/40910.
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In this thesis we investigate the performance of spatial reuse in wireless networks. More specifically, we investigate the performance of location-based spatial reuse built upon the identification of links in the network that form Collision-Free Sets (CFSs). We develop algorithms that efficiently find such CFSs. The main focus of this thesis is the application of our CFS-based algorithms to emerging WiMAX (Worldwide Interoperability for Microwave Access) networks. However, we will also apply our CFS-based algorithms to smaller scale networks, as well as to the issue of QoS routing. This thesis makes several contributions. We first show how CFSs can be found within polynomial time in small scale wireless networks. We then probe how CFSs can be used to enhance network efficiency when location is available. We also explore how CFS determination is affected by location error, determining what level of location error renders the use of CFSs ineffective. In this context, we discuss the density of access points required to ensure CFS-based spatial reuse remains effective. We then focus on the use of CFSs in emerging multihop WiMAX networks, showing in detail how enhanced spatial reuse is delivered. The spatial reuse gains are probed both in the presence of realistic channel conditions and realistic location errors. Within the context of the IEEE 802.16 standard we show how CFSs can enhance, by factors of two, the VoIP capacity of multihop WiMAX networks. We also discuss how our CFS algorithms can be applied to other ongoing efforts aimed at improving VoIP capacity in WiMAX networks. Finally, an application of our CFS algorithms in the context of QoS routing is studied. Specifically, we develop a two-hop QoS routing protocol that guarantees QoS specifications by securing higher bandwidth for the chosen routes.
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Williams, Mark, and n/a. "Spatial data from image sequences." University of Otago. Department of Computer Science, 2007. http://adt.otago.ac.nz./public/adt-NZDU20080130.131733.
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There are many existing methods for capturing three dimensional data from two dimensional images. Methods based on images captured from multiple view-points require solving the correspondence problem: establishing which points in each image represent the same points in the scene. Most attempts at solving the correspondence problem require carefully controlled lighting and reference points within the scene.
A new method captures many consecutive images to form a dense spatiotemporal volume as the camera-or scene-undergoes controlled motion. Feature points in the scene move along predictable paths within this volume. Analysing the exact motion of features determines their three dimensional position in the scene.
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García, Ordoñez Luis. "Perfomance limits of spatial multiplexing mimo systems." Doctoral thesis, Universitat Politècnica de Catalunya, 2009. http://hdl.handle.net/10803/22735.
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Los canales multiple-input multiple-output (MIMO) proporcionan una forma abstracta y general de modelar un gran número de sistemas de comunicaciones. Los canales MIMO inalámbricos, en concreto, han despertado un gran interés en la comunidad investigadora durante la última década, puesto que aportan mejoras significativas en términos de eficiencia espectral y fiabilidad frente a los sistemas single-input single-output (SISO) tradicionales.
Esta tesis se concentra en sistemas MIMO de multiplexado espacial con conocimiento perfecto de canal (CSI) en ambos lados del enlace de comunicaciones. Las técnicas de multiplexado espacial engloban a todos aquellos sistemas de transmisión MIMO que dividen el flujo de datos de entrada en múltiples subflujos independientes para transmitirlos después de forma simultánea. Cuando se posee CSI perfecto en transmisión, la adaptación de dichos subflujos al estado del canal resulta en notables mejoras de las prestaciones del sistema de comunicaciones. Dentro de esta filosofía destacan los transceptores MIMO lineales por su gran relevancia práctica.
El diseño de transceptores MIMO lineales se ha abordado extensivamente en la literatura durante las tres últimas décadas bajo una gran variedad de criterios de optimización. Las prestaciones de estos esquemas, en cambio, no se han investigado analíticamente, de forma que medidas de rendimiento tales como la probabilidad de error de bit promedio (BER) y la probabilidad de outage se han evaluado mediante simulaciones numéricas, las cuales no proporcionan una visión intuitiva del comportamiento del sistema. Los análisis teóricos, en cambio, ayudan a identificar los grados de libertad en el diseño y a comprender mejor su impacto en las prestaciones obtenidas. La presente tesis parte de esta necesidad y proporciona una caracterización analítica de la BER promedio y la probabilidad de outage bajo diferentes modelos de canal. El régimen de alta relación señal a ruido (SNR) ha recibido una atención especial y las prestaciones del sistema se han investigado desde dos puntos de vista diferentes. En primer lugar, adoptando una perspectiva más práctica, hemos caracterizado las curvas de BER promedio y probabilidad de outage en términos de dos parámetros clave: la ganancia en diversidad y la ganancia de agrupación. A continuación nos hemos centrado en el marco del diversity and multiplexing tradeoff.
De esta forma, hemos podido analizar conjuntamente la capacidad del sistema para tratar con la naturaleza aleatoria del canal pero, también, la capacidad de acomodar una tasa de transmisión superior cuando la SNR crece.
En esta tesis se han evaluado las prestaciones de los transceptores MIMO lineales analíticamente y de forma simultánea para los modelos de canal MIMO inalámbricos más comunes, tales como el canal Rayleigh incorrelado o semicorrelado, o el canal Ricean incorrelado. Para alcanzar este objetivo, hemos obtenido una formulación general que unifica la caracterización probabilística de los autovalores de matrices aleatorias Hermíticas con una determinada estructura, que incluye los modelos de canal anteriores como casos particulares. En efecto, la formulación propuesta y los resultados obtenidos proporcionan un marco sólido para el análisis de las prestaciones de los sistemas MIMO, pero también pueden ser muy útiles en otras áreas del procesado estadístico de la señal y las comunicaciones.
Finalmente, como conclusión al análisis realizado en esta tesis, se han evidenciado las limitaciones inherentes a los sistemas prácticos de multiplexado espacial con conocimiento de canal estudiados. En consecuencia, se han propuesto esquemas alternativos que tratan dichas limitaciones y superan las prestaciones de los diseños prácticos disponibles en la literatura.Multiple-input multiple-output (MIMO) channels are an abstract and general way to model many different communication systems of diverse physical nature. In particular, wireless MIMO channels have been attracting a great interest in the last decade, since they provide significant improvements in terms of spectral efficiency and reliability with respect to single-input single-output (SISO) channels. In this thesis we concentrate on spatial multiplexing MIMO systems with perfect channel state information (CSI) at both sides of the link. Spatial multiplexing is a simple MIMO transmit technique that does not require CSI at the transmitter and allows a high spectral efficiency by dividing the incoming data into multiple independent substreams and transmitting each substream on a different antenna. When perfect CSI is available at the transmitter, channel-dependent linear precoding of the data substreams can further improve performance by adapting the transmitted signal to the instantaneous channel eigen-structure. An example of practical relevance of this concept is given by linear MIMO transceivers, composed of a linear precoder at the transmitter and a linear equalizer at the receiver. The design of linear MIMO transceivers has been extensively studied in the literature for the past three decades under a variety of optimization criteria. However, the performance of these schemes has not been analytically investigated and key performance measures such as the average bit error rate (BER) or the outage probability have been obtained through time-comsuming Monte Carlo simulations. In contrast to numerical simulations, which do not provide any insight on the system behavior, analytical performance expressions help the system designer to identify the degrees of freedom and better understand their influence on the system performance. This thesis attempts to fill this gap by providing analytical average and outage performance characterizations in some common MIMO channel models. More exactly, we derive exact expressions or bounds (depending on the case) for the average BER and the outage probability of linear MIMO transceivers designed under a variety of design criteria. Special attention is given to the high signal-to-noise ratio (SNR) regime, where the system performance is investigated under two different perspectives. First, from a more practical point-of-view, we characterize the average BER and outage probability versus SNR curves in terms of two key parameters: the diversity gain and the array gain. Then, we focus on the diversity and multiplexing tradeoff framework in order to take into consideration the capability of the system to deal with the fading nature of the channel, but also its ability to accommodate higher data rates as the SNR increases. The performance of linear MIMO transceivers is simultaneously analyzed for the most common wireless MIMO channel models such as the uncorrelated and semicorrelated Rayleigh, and the uncorrelated Rician MIMO fading channels. For this purpose, we have obtained a general formulation that unifies the probabilistic characterisation of the eigenvalues of Hermitian random matrices with a specific structure, which includes the previous channel distributions as particular cases, i.e., the uncorrelated and semicorrelated central Wishart, the uncorrelated noncentral Wishart, and the semicorrelated central Pseudo-Wishart distributions. Indeed, the proposed formulation and derived results provide a solid framework for the analytical performance evaluation of MIMO systems, but it could also find numerous applications in other fields of statistical signal processing and communications. Finally, and as a consequence of our performance analysis, limitations inherent to all practical linear MIMO transceiver designs have been enlightened. Accordingly, new schemes have been proposed which achieve considerable performance enhancements with respect to classical linear MIMO transceivers.
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Rodríguez, Amor Daniel. "Population and evolutionary dynamics in spatial systems." Doctoral thesis, Universitat de Girona, 2013. http://hdl.handle.net/10803/128501.
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Physical and mathematical models are extremely useful to understand key processes in population and evolutionary dynamics. Such models allow the study of many diverse features in spatial systems such as front propagation, the evolution of the population number density, interactions between species (or individuals), the evolution of strategies, etc. This thesis is devoted to several physical models describing spatial systems. The first model focuses on the effects of the population structure in two-dimensional invasive fronts. An expression for the front speed is derived from the equations for structured populations. The second model is devoted to the study of Vesicular Stomatitis Virus infections. In this case, reaction-diffusion equations are used to describe the interactions between uninfected cells, infected cells and virus populations. In the last model, the Prisoner's Dilemma game is used to study the evolution of cooperation and defection strategiesEls models físics i matemàtics són de gran utilitat a l'hora d'entendre processos clau en la dinàmica poblacional i evolutiva. Aquests models permeten l'estudi de característiques molt diverses dels sistemes espacials, com són la propagació de fronts, l'evolució de la densitat de població, les interaccions entre espècies (o individus), l'evolució d'estratègies, etc. Aquesta tesi presenta diversos models físics que descriuen sistemes espacials. El primer model estudia els efectes de l'estructura de la població en fronts invasius bidimensionals. Una expressió per la velocitat del front és derivada de les equacions per a poblacions estructurades. El segon model es consagra a l’estudi d’infeccions del Vesicular Stomatitis Virus. En aquest cas, s’utilitzen equacions de reacció-difusió per descriure les interaccions entre les poblacions de cèl·lules no infectades, cèl·lules infectades i virus. A l’últim model, el joc del Dilema del Presoner s'utilitza per estudiar l'evolució d'estratègies de cooperació i deserció
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Oukbir, Karim. "Indiscernibility and Vagueness in Spatial Information Systems." Doctoral thesis, KTH, Numerical Analysis and Computer Science, NADA, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3634.
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We investigate the use of the concept of indiscernibilityand vagueness in spatial information systems. To representindiscernibility and vagueness we use rough sets, respectivelyfuzzy sets. We introduce a theoretical model to supportapproximate queries in information systems and we show howthose queries can be used to perform uncertain classi.cations.We also explore how to assess quality of uncertainclassi.cations and ways to compare those classi.cations to eachother in order to assess accuracies. We implement the querylanguage in an SQL relational language to demonstrate thefeasibility of approximate queries and we perform an experimenton real data using uncertain classi.cations.
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Briggs, Jonathan Francis. "Particle filters for high dimensional spatial systems." Thesis, University of Auckland, 2011. http://hdl.handle.net/2292/7659.
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The objective of this work is to develop new filtering methodologies that allow state-space models to be applied to high dimensional spatial systems with fewer and less restrictive assumptions than the currently practical methods. Reducing the assumptions increases the range of systems that the state-space framework can be applied to and therefore the range of systems for which the uncertainty in estimates can be quantified and statements about the risk of particular outcomes made. The particle filter was developed to meet this objective because restrictive assumptions are fundamental to the alternative methods. Two barriers to applying particle filters to high dimension spatial systems were identified. The first barrier is the lack of a flexible and practically applicable high dimensional noise distribution for the evolution equation in the case of non-negative states. The second barrier is the tendency of the Monte Carlo ensemble approximating the state distribution updated by observations to collapse down to a single point. The first barrier is overcome by defining the evolution equation noise distribution using very flexible meta-elliptical distributions. The second barrier is overcome by using a particle smoother across a sequence of spatial locations to generate the Monte Carlo ensemble. Because this location-domain particle smoother only considers one location at a time, the dimensionality of the sampling problem is reduced and a diverse ensemble can be generated. The location-domain particle smoother requires that the evolution noise distribution be defined using a meta-elliptical distribution and that the observation errors at different locations are independent. If the system has spatial resolution that is 'too fine' and there are 'too many' observed locations then the number of distinct particles can fall below an acceptable level at the beginning of the location sequence. A second method for overcoming ensemble collapse is proposed for these systems. In the second method a particle smoother is used to generate separate samples from the marginal state distributions at each location. The marginal samples are combined into a single sample from the joint state distribution spanning all of the locations using a copula. This second method requires that the state distribution is meta-elliptical and that the observation errors at different locations are independent. The assumptions required by the proposed methods are fewer and vastly less restrictive than the assumptions required by currently practical methods. The statistical properties of the new methods are explored in a simulation study and found to out-perform a standard particle filter and the popular ensemble Kalman filter when the Kalman assumptions are violated. A demonstration of the new methods using a real example is also provided.
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Fukuzono, Hayato. "Spatial Signal Processing on Distributed MIMO Systems." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/217206.
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Huang, Wenzong. "Spatial queueing systems and reversible markov processes." Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/24871.
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Hirst, J. M. "Spatial impression in multichannel surround sound systems." Thesis, University of Salford, 2006. http://usir.salford.ac.uk/2226/.
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Spatial impression in both concert halls and reproduced sound has been identified as an important attribute of the listening experience. In this study, the synthesis and objective measurement of spatial impression in reproduced sound is examined. A novel, multichannel spatializing technique for musical synthesis has been developed that entailed the separation of the individual harmonics of a musical note that were spatially distributed over multichannel surround systems. Subjective testing of the techniques revealed that the perceived degree of spatial impression significantly increased as the angular spread of harmonics increased, however, extending the spatial spread beyond 90° did not significantly increase the perception of spatial impression. The concert hall measure of spatial impression, the interaural cross correlation coefficient (IACC) was used to objectively measure the effects of the spatializing techniques. The IACC measurements displayed a strong correlation to the subjective results. Further examination of the IACC measurement indicated the possibility of it’s adaptation to multichannel surround sound in general. A method of adapting IACC to reproduced sound was further developed that involved comparing IACC measurements taken in a concert hall to IACC measurements taken in reproduced versions of the same concert hall. The method was first conducted as a simulation using basic auralisation techniques. Real concert hall measurements and reproduction systems were then employed. Results showed that the method was able to discriminate between the spatial capabilities of a number of different surround sound systems and rank them in a predictable order. The results were further validated by means of a subjective test. In an attempt to sensitise the IACC measurement, the frequency dependency of IACC was investigated by means of a subjective test. The results indicated that a perceptually more accurate indication of spatial impression may be gained by applying a frequency-dependent weighting to IACC measurements. This may be useful in the spatial measurement of both reproduced sound and concert halls.
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White, Andrew. "Temporal and spatial dynamics of ecological systems." Thesis, University of Liverpool, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338459.
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BRAZ, JOAO ALFREDO CAL. "SIGNAL DETECTION IN SPATIAL MODULATION MULTIANTENNA SYSTEMS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2015. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=26134@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Modulação Espacial é um método de transmissão por múltiplas antenas recentemente proposto,designado por MIMO-SIM, que associa informação à escola das antenas transmissoras. Isto possibilita a redução do número de cadeias de radiofrequência e, consequentemente, a imimplementação de sistemas de comunicação que consomem menos energia. O novo esquema de comunicação dos sistemas MIMO-SIM exige que, do lado redeptor, novas e eficientes estratégias de detecção do sinal transmitido sejam elaborados. O detector de máxima verossimilhança (ML), que fornece o desempenho ótimo, é de inviável implementação devido ao elevado custo computacional. Os detectores Sphere Decoding (SD) são comumente aplicados aos sistemas MIMO e atingem o desempenho ótimo a menor custo de computação. Um algoritmo SD que considera as caractéristicas do sinal SM foi desenvolvido, resultando em redução de custo computacional em relação ao detector ML e aos algoritmos SD convencionais. A elevada sensibilidade da complexidade dos algoritmos SD à variação da relação sinal-ruído (SNR) motivou o desenvolvimento de técnicas de detencção subótimas. Estratégias baseadas em detecção em grupos foram propostas, e os algoritmos de detecção aninhada MLA-M e MLA-C tiveram sua complexidade e desempenho avaliados em diferetes configurações e cenários de canal. Uma nova família de detectores, que realiza a detecção da combinação de antenas transmissoras e dos símbolos transmitidos em fases distintas, foi proposto, eo algoritmo List-BMP-LR-MMSE atingiu desempenho de detecção quase ótimo com baixo custo computacional, menos sensível à variação de SNR. Baseado na estratégia de detecção em duas fases, um novo detector de baixo custo foi desenvolvido para sistemas SM com codificação espácio-temporal.
Spatial Modulation is a recently proposed multiantenna transmission scheme, designated as SM-MIMO, that associates information to the transmit antenna selection, thus enabling the reduction of the number of radiofrequency chains and , consequently, the implementation of less power consuming communication systems. The novel SM-MIMO communication scheme requires, at the receiver side, the development of new and efficient signal detection strategies of the optimal performance, is infeasible to implement due to the high computational cost. Sphere Decoding detectors (SD) are customarily applied to MIMO systems and attain optimal performance with lower computational cost.An SD algorithm, tailored following SM signal characteristics was deloped, resulting in computational cost reduction compared to ML detector and conventional MIMO SD algorithms. The hogh computational sensitivity of SD algorithms to the signal-to-noise ratio (SNR) variation motivated the development of subboptimal detection techniques. Strategies based in group detection were propsed, and nested detection algorithms LA-M and MLA-C had their complexity and performance evaluated in different configurations and channel scenarios. A new family of detectors, that performs the detection of the transmit antenna combinations and the transmitted symbols in two distinct stages,was proposed, and List-BMP-LR-MMSE algorithm attained near -optimal detection performace with low computational complexity, less sensitive to SNR variation. Based on the two-stage detection strategy, a new low-complexity detector was developed to space-time coded SM systems.
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Guzmán, Michell. "On the expressiveness of spatial constraint systems." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLX064/document.
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Les comportement épistémiques, mobiles et spatiaux sont omniprésent dans les systèmes distribués aujourd’hui. La nature intrinsèque épistémique de ces types de systèmes provient des interactions des éleménts qui en font parties. La plupart des gens sont familiarisés avec des systèmes numériques où les utilisateurs peuvent partager ses croyances, opinions et même des mensonges intentionnels (des canulars). Aussi, les modèles de ces systèmes doivent tenir compte des interactions avec d’autres de même que leur nature distribués. Ces comportements spatiaux et mobiles font part d’applications où les données se déplacent dans des espaces (peut-être imbriqués) qui sont définis par, par exemple, cercles d’amis, des groupes, ou des dossiers partagés. Nous pensons donc qu’une solide compréhension des notion d’espaces, de mobilité spatial ainsi que le flux d’information épistémique est cruciale dans la plupart des modèles de systèmes distribués de nos jours.Les systèmes de contrainte (sc) fournissent les domaines et les opérations de base pour les fondements sémantiques de la famille de modèles déclaratifs formels de la théorie de la concurrence connu sous le nom de programmation concurrent par contraintes (pcc). Les systèmes des contraintes spatiales (scs) représentent des structures algébriques qui étendent sc pour raisonner sur les comportement spatiaux et épistémiques de base tel que croyance et l’extrusion. Les assertions spatiales et épistémiques peuvent être vues comme des modalités spécifiques. D’autres modalités peuvent être utilisées pour les assertions concernant le temps, les connaissances et même pour l’analyse des groupes entre autres concepts utilisés dans la spécification et la vérification des systèmes concurrents.Dans cette thèse nous étudions l’expressivité des systèmes de contraintes spatiales dans la perspective générale du comportement modal et épistémique. Nous montrerons que les systèmes de contraintes spatiales sont assez robustes pour capturer des modalités inverses et pour obtenir de nouveaux résultats pour les logiques modales. Également, nous montrerons que nous pouvons utiliser les scs pour exprimer un comportement épistémique fondamental comme connaissance. Finalement, nous donnerons une caractérisation algébrique de la notion de l’information distribuée au moyen de constructions sur scsEpistemic, mobile and spatial behaviour are common place in today’s distributed systems. The intrinsic epistemic nature of these systems arises from the interactions of the elements taking part of them. Most people are familiar with digital systems where users share their beliefs, opinions and even intentional lies (hoaxes). Models of those systems must take into account the interactions with others as well as the distributed quality these systems present. Spatial and mobile behaviour are exhibited by applications and data moving across (possibly nested) spaces defined by, for example, friend circles, groups, and shared folders. We therefore believe that a solid understanding of the notion of space and spatial mobility as well as the flow of epistemic information is relevant in many models of today’s distributed systems.Constraint systems (cs’s) provide the basic domains and opera- tions for the semantic foundations of the family of formal declarative models from concurrency theory known as concurrent constraint programming (ccp). Spatial constraint systems (scs’s) are algebraic structures that extend cs’s for reasoning about basic spatial and epistemic behaviour such as belief and extrusion. Both spatial and epistemic assertions can be viewed as specific modalities. Other modalities can be used for assertions about time, knowledge and even the analysis of groups among other concepts used in the specification and verification of concurrent systems.In this thesis we study the expressiveness of spatial constraint systems in the broader perspective of modal and epistemic behaviour. We shall show that spatial constraint systems are sufficiently robust to capture inverse modalities and to derive new results for modal logics. We shall show that we can use scs’s to express a fundamental epistemic behaviour such as knowledge. Finally we shall give an algebraic characterization of the notion of distributed information by means of constructors over scs’s
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Lopes, Batres Mario. "Integrating Spatial Audio in Voice Guidance Systems." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-289640.
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Navigation systems are commonly used in our daily lives. Research has shown that spatial audio presents one opportunity for more effectively communicating to the driver the direction of the next manoeuvre. This thesis project proposes a new feature for the spatialisation of the audio cues triggered by a mobile navigation system by using a virtualised vector-based panning (VVBP) architecture for the encoding and decoding. The prototype developed during this thesis enables the spatialisation using headphones- or speakers- based systems. This study aims to promote a new sound experience to the user, which can be used to increase the safety and performance of driving. Based on an expert review and a user test, the application was tested on different scenarios. The participants selected during these sessions were part of HERE Technologies, which made possible to reach design experts who knew the current application provided by the company beforehand, making easier the comparison with the proposal. This selection could also present a limitation on the study since the users might have a personal bias for seeing new features in a product which have already worked on. Analysis of the results obtained during the testing session demonstrated high satisfaction with the feature by the users and a better understanding of their surroundings. Consequently, this indicates that spatial audio can improve the performance of driving by introducing a new source of information for positioning the next turn or obstacle. Further research is needed to identify other factors that could strengthen the effectiveness of the product.Navigationssystem används ofta i våra dagliga liv. Forskning har visat att rumsligt ljud ger ett tillfälle att effektivare kommunicera till föraren i riktningen för nästa manöver. Detta avhandlingsprojekt föreslår en ny funktion för spatialisering av ljudkoder som utlöses av ett mobilnavigeringssystem med hjälp av en virtualiserad vektorbaserad panorering (VVBP) arkitektur för kodning och avkodning. Prototypen som utvecklats under denna avhandling möjliggör spatialisering med hörlurar eller högtalarbaserade system. Denna studie syftar till att främja en ny ljudupplevelse för användaren, som kan användas för att öka säkerheten och prestandan vid körning. Baserat på en expertgranskning och ett användartest testades applikationen på olika scenarier. Deltagarna som valdes ut under dessa sessioner var en del av HERE Technologies, som gjorde det möjligt att nå konstruktionsexperter som kände till den nuvarande applikationen från företaget i förväg, vilket underlättar jämförelsen med förslaget. Detta val kan också utgöra en begränsning av studien eftersom användarna kan ha en personlig fördom för att se nya funktioner i en produkt som redan har arbetat med. Analys av resultaten som erhölls under testperioden visade hög tillfredsställelse med funktionen hos användarna och en bättre förståelse för deras omgivning. Konsekvensen indikerar att rumsligt ljud kan förbättra körförmågan genom att införa en ny informationskälla för positionering av nästa sväng eller hinder. Ytterligare forskning behövs för att identifiera andra faktorer som kan stärka produktens effektivitet.
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Flanagan, Rachel Erin. "Two Autonomous Spatial Systems and Their Juxtaposition." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/79429.
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This thesis explores the idea of two autonomous spatial systems and their interaction: a syntactic grid and a pure formal volume. The juxtaposition of these two elements allows for insight into and exploration of their autonomous ordering potentialities, as well as the potential relationships or the presence of both systems. The syntactic grid articulates structure and strength for the architectural project , while the pure volume translates the programmatic function and their distinction from the grid.Master of Architecture
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Chen, Chih-Keng. "Nonholonomic control of coupled spatial multibody systems." Case Western Reserve University School of Graduate Studies / OhioLINK, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=case1057091907.
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Yang, Shuang. "Multidimensional microfluidic bioseparation systems with spatial multiplexing." College Park, Md.: University of Maryland, 2008. http://hdl.handle.net/1903/8725.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2008.Thesis research directed by: Dept. of Mechanical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Ma, Jingsheng. "Integrating GIS and spatial statistical tools for the spatial analysis of health-related data." Thesis, University of Sheffield, 2001. http://etheses.whiterose.ac.uk/14818/.
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Spatial Statistical Analysis (SSA) and Geographical Information Systems (GIS) are instrumental in many areas of geographical study. However, their use tends to be separate one from another. This has prevented their potential in many application areas from being realised. This research is an attempt to bring the two technologies together for a specific application area - health research. There are two research objectives. The first and main objective is to construct a software package - SAGE - by integrating necessary SSA techniques with ARC/INFO, a GIS, to enable the user to undertake a coherent study of area-based health-related data. The second objective is to evaluate and demonstrate SAGE through a case study. A range of SSA techniques was identified to be useful for addressing typical health questions. A three-tier client-server model was suggested and argued to be the most appropriate for integration as it takes advantages of both the loose-coupling and close-coupling approaches. Under this model, a SSA component forms the client, while ARCH/INFO functions as the server. They are linked through the middle tier - the linking agent. The development of SAGE provided experiences useful for developing a generic SSA module in the future for any GIS that confonns to a set of well-defined standard application interfaces. An empirical study of colorectal cancer (CRC) incidence for the city of Sheffield using SAGE is presented. It shows the usefulness of the SAGE regionalisation tool in constructing an appropriate regional framework for subsequent data analyses and of both exploratory and confirmatory spatial data analysis in exploring the characteristics of CRC incidence. Some weaknesses of SAGE are identified, while remedies for them are suggested. Future work is recommended. The SAGE User Guide, related publications and the SAGE source and executable code as well as the data used in the case study are enclosed for reference.
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Nedas, Konstantinos A. "Semantic Similarity of Spatial Scenes." Fogler Library, University of Maine, 2006. http://www.library.umaine.edu/theses/pdf/NedasKA2006.pdf.
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Pennington, Sandra Lynn. "Automatic geometric modeling of spatial mechanism links." Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/91056.
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This thesis introduces GENMOD, a collection of subroutines which allow automatic geometric modeling of 3-D models for spatial links or linkages given a minimum amount of information as input. The subroutines utilize the CADCD (CADAM, Inc.) geometry interface software to enter 3-D data directly into the CAD/CAM database. Wire-frame and surface models are produced. Input is accepted from user created files with a standardized format allowing the GENMOD subroutines to be implemented regardless of the synthesis and analysis routines used. The realistic visualization of a mechanism during the synthesis and analysis process can help the mechanism designer to eliminate unacceptable linkage configurations in the early design stages thereby saving time and money. A complete description of the subroutines is provided in addition to sample graphic output.M.S.
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McKnight, Douglas J. "An electronically addressed spatial light modulator." Thesis, University of Edinburgh, 1989. http://hdl.handle.net/1842/281.
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Coherent optical data processing is recognised to be a natural solution to certain information processing problems. Attempts to exploit the benefits of optical processing are limited by the quality of available Spatial Light Modulators. Spatial Light Modulators are devices which controllably impress information onto the amplitude or phase of an optical wavefront. They are used both to input data into an opticaI system and as modulating elements within the system (often in the Fourier plane of a Fourier transform processor). This thesis describes the successful development of an electronically addressed spatial light modulator using liquid crystal as the light modulating material and a silicon integrated circuit as the addressing medium. It is a pixelated binary spatial light modulator operating in reflection. Each pixel contains a memory element which stores the programmed logical state of the pixel. The addressing and pixel circuits were fabricated in a 1.5m nMOS technology on a 10 mm square chip. Th e pixels are arranged on a square array containing 50 x 50 elements. The liquid crystal was configured to modulate the light amplitude using the hybrid field effect in a nematic liquid crystal. The spatial light modulator is used as a Fourier plane filter in a coherent optical processing system. Its performance is assessed and the direction of future research into this type of spatial light modulator is discussed.
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Williams, Richard David. "Organisation and analysis of spatial data." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304464.
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Mendez, Chaves Diego. "A Framework for Participatory Sensing Systems." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4135.
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Participatory sensing (PS) systems are a new emerging sensing paradigm based on the participation of cellular users in a cooperative way. Due to the spatio-temporal granularity that a PS system can provide, it is now possible to detect and analyze events that occur at different scales, at a low cost. While PS systems present interesting characteristics, they also create new problems. Since the measuring devices are cheaper and they are in the hands of the users, PS systems face several design challenges related to the poor accuracy and high failure rate of the sensors, the possibility of malicious users tampering the data, the violation of the privacy of the users as well as methods to encourage the participation of the users, and the effective visualization of the data. This dissertation presents four main contributions in order to solve some of these challenges.
This dissertation presents a framework to guide the design and implementation of PS applications considering all these aspects. The framework consists of five modules: sample size determination, data collection, data verification, data visualization, and density maps generation modules. The remaining contributions are mapped one-on-one to three of the modules of this framework: data verification, data visualization and density maps.
Data verification, in the context of PS, consists of the process of detecting and removing spatial outliers to properly reconstruct the variables of interest. A new algorithm for spatial outliers detection and removal is proposed, implemented, and tested. This hybrid neighborhood-aware algorithm considers the uneven spatial density of the users, the number of malicious users, the level of conspiracy, and the lack of accuracy and malfunctioning sensors. The experimental results show that the proposed algorithm performs as good as the best estimator while reducing the execution time considerably.
The problem of data visualization in the context of PS application is also of special interest. The characteristics of a typical PS application imply the generation of multivariate time-space series with many gaps in time and space. Considering this, a new method is presented based on the kriging technique along with Principal Component Analysis and Independent Component Analysis. Additionally, a new technique to interpolate data in time and space is proposed, which is more appropriate for PS systems. The results indicate that the accuracy of the estimates improves with the amount of data, i.e., one variable, multiple variables, and space and time data. Also, the results clearly show the advantage of a PS system compared with a traditional measuring system in terms of the precision and spatial resolution of the information provided to the users.
One key challenge in PS systems is that of the determination of the locations and number of users where to obtain samples from so that the variables of interest can be accurately represented with a low number of participants. To address this challenge, the use of density maps is proposed, a technique that is based on the current estimations of the variable. The density maps are then utilized by the incentive mechanism in order to encourage the participation of those users indicated in the map. The experimental results show how the density maps greatly improve the quality of the estimations while maintaining a stable and low total number of users in the system.
P-Sense, a PS system to monitor pollution levels, has been implemented and tested, and is used as a validation example for all the contributions presented here. P-Sense integrates gas and environmental sensors with a cell phone, in order to monitor air quality levels.
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Kudo, Riichi. "Efficient Spatial Resource Management for Broadband MIMO Systems." 京都大学 (Kyoto University), 2010. http://hdl.handle.net/2433/126783.
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Bäckström, Anna, and Louise Wändin. "Spatial Hypertext Editing Tools for Wiki Web Systems." Thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-97795.
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This thesis considers the provision of comprehensible and interpretable tools in the wiki web system. This implies that an extensive research has been made upon the system, i.e., a hypertext system at the Spatial Information Architecture Laboratory (SIAL) at RMIT University in Australia. The process to develop these tools is based on certain requirements due to the user. The wiki web system is becoming more and more common in communities, projects, education etc. Companies provide wiki systems to share project information as an online collaborative tool. Another way of using a wiki is as an encyclopaedia. This is currently done in Wikipedia which has been an online wiki encyclopaedia since 2001. This solution is an exceptional way to extract and share information quickly. The problem in a wiki is to get an interpretable overview of the whole system, as well as to organise the pages and the structure of the pages in a fine way. The problem is that the number of wiki pages, which are represented as hyperlinks in the system, quickly grown. Therefore, the user needs to be able to navigate within the system and this will require a map. The proposed solution is to provide such a map, namely, a global view of the system. Likewise, the user needs to be able to organize the information, and this will require special tools. The proposed solution is to provide such tools, namely, split and merge tools. In order to develop these tools, direct manipulation and usability should be taken into consideration
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Wu, Xiping. "Wireless communication systems based on spatial modulation MIMO." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/10505.
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Spatial modulation (SM) is a unique single-stream, multiple-input multiple-output (MIMO) transmission technique. Unlike traditional MIMO schemes, SM sends out signals through a single active antenna, and achieves multiplexing gains by encoding information bits into the index of the currently active antenna. In contrast to multi-stream MIMO systems, this particular characteristic offers great superiority in two main aspects. Firstly, SM completely avoids inter-channel interference. Secondly, SM requires a single radio-frequency chain, regardless of the number of antennas used, and therefore exhibits a significant energy saving. However, the property of a single active antenna challenges the channel estimation process for SM: the transmit antennas have to be activated sequentially for sending pilot signals. As a result, the time consumed in pilot transmission is proportional to the number of transmit antennas. However, this fact has so far been neglected in related research. Also, published research on SM has focused on point-to-point communications, and few have covered a network perspective. In this thesis, a comprehensive study is undertaken on SM systems in single-user, multi-user and multi-cell scenarios. As a unique three-dimensional modulation scheme, SM enables a trade-off between the size of the signal constellation diagram and the size of the spatial constellation diagram. In this thesis, an optimum transmit structure is proposed for SM to employ an adaptive scale of antennas against channel correlations. Unlike traditional antenna selection methods, this new approach is not sensitive to fast fading, due to the exploitation of statistical channel state information (CSI) instead of instant CSI. The proposed transmit structure is demonstrated to have a near-optimal performance against exhaustive search, while achieving very low computational complexity. In addition, three novel methods are developed to improve the channel estimation process for SM. A first method estimates the entire MIMO channel by sending pilot signals through only one of the transmit antennas, among which the channel correlation is exploited. In a similar way but focusing on the receiver, a second method can improve the estimation accuracy without increasing the pilot sequence length. A third method balances the transmission power between pilot and data to minimise the bit error rate. A framework of combined channel estimation is also proposed, in which the three methods are jointly applied. Furthermore, the antenna allocation in multi-user SM is studied, in order to explore multi-user diversity gains. A method that jointly manages transmit antennas and receive antennas for all co-channel users is proposed. The aim of this new method is to maximise the channel capacity for each user, and the fairness among users is taken into account. It is demonstrated that the proposed method significantly improves the performance of multi-user SM, especially when serving a large number of users. Finally, a novel cooperative scheme is proposed for SM in a multi-cell scenario. Based on the concept of coordinated multi-point transmission (CoMP), this scheme enables the coordinated users to swap the base station antennas pertaining to them. A three-tier cellular architecture is further developed to switch between CoMP and the cooperative scheme.
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LISITANO, DOMENICO. "Spatial damping identification and control of mechanical systems." Doctoral thesis, Politecnico di Torino, 2019. http://hdl.handle.net/11583/2734827.
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Dakowicz, Maciej. "A unified spatial data structure for GIS." Thesis, University of South Wales, 2009. https://pure.southwales.ac.uk/en/studentthesis/a-unified-spatial-data-structure-for-gis(1e1d3b0e-586a-4b1d-9027-f03c61b30a68).html.
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Most GIS systems use separate thematic "layers" to store different types of spatial data. Each of them contains specific characteristics of the area, so there are separate layers for the distribution of buildings, the road network or the relief of the terrain. The spatial information used in GIS can be grouped into four main groups: polygonal maps, terrain models, networks and discrete, unconnected objects. Polygonal maps and terrain models are considered to be "field" models of space, covering the whole map, so there is some kind of information available at every location. On the other hand, networks and discrete objects are representations of the "object" model of space, in which the map is populated by entities and the space between them is empty. Choropleth maps are the most common examples of polygonal maps and the three main representations of terrain models are Triangular Irregular Networks (TINs), grids and contour lines. Networks consist of connected edges, while discrete objects can be points, lines or polygons. In networks, polygonal maps and surfaces there is some model of connectivity available. Polygons are adjacent to each other, as are the elements in terrain models. Network data is connected along the edges and junctions are defined. Unconnected objects need have no connectivity information, but in that case the possible spatial queries are limited. The layers can be stacked on top of each other to perform various operations and analyses on them. However, there is no consistent method applicable to all data types because GIS has traditionally separated field and object layers and used different data structures to represent them. This thesis presents a unified spatial data model for these most common types of spatial information and intends to show that it has clear advantages for geographical analysis. The idea is to represent discrete object models as fields, so there is information available at all locations. The model is based on the Voronoi Diagram (VD) and the dual Delaunay Triangulation (DT), two well studied geometric structures. Depending on the application it may be appropriate to represent the data on the map by the simple VD/DT, or their derivatives - the Constrained DT (CDT), the Line Segment VD (LSVD) or the crust and the skeleton. All of these are directly related to each other and may be handled in a single manner in the computer. Algorithms and the storage of these various forms of the VD using the quad-edge data structure is described. This structure may be updated locally, and dynamic algorithms for each of these representations are presented. This allows for the development of a common interactive framework for what are traditionally considered to be distinct data types. The unified model is illustrated by a variety of GIS applications, and the implementation of several traditional GIS operations and queries is discussed.
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Yü, Ying-siu. "Spatial pattern of unemployment in Hong Kong." [Hong Kong : University of Hong Kong], 1986. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12333682.
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Monteiro, Francisco António Taveira Branco Nunes. "Lattices in MIMO spatial multiplexing : detection and geometry." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610576.
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Wealands, Stephen Russell. "Quantitative methods for hydrological spatial field comparison /." Connect to thesis, 2006. http://eprints.unimelb.edu.au/archive/00002722.
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Grubesic, Tony H. "A spatial analysis of internal accessibility." Connect to this title online, 2001. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu997995873.
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Thesis (Ph. D.)--Ohio State University, 2001.Title from first page of PDF file. Document formatted into pages; contains xiv, 234 p.; also contains graphics (some col.). Includes abstract and vita. Advisor: Morton E. O'Kelly, Dept. of Geography. Includes bibliographical references (p. 225-234).
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Ware, John Mark. "Multi-scale data storage schemes for spatial information systems." Thesis, University of South Wales, 1994. https://pure.southwales.ac.uk/en/studentthesis/multiscale-data-storage-schemes-for-spatial-information-systems(38746248-a8d7-4527-ab7a-e874140eda07).html.
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This thesis documents a research project that has led to the design and prototype implementation of several data storage schemes suited to the efficient multi-scale representation of integrated spatial data. Spatial information systems will benefit from having data models which allow for data to be viewed and analysed at various levels of detail, while the integration of data from different sources will lead to a more accurate representation of reality. The work has addressed two specific problems. The first concerns the design of an integrated multi-scale data model suited for use within Geographical Information Systems. This has led to the development of two data models, each of which allow for the integration of terrain data and topographic data at multiple levels of detail. The models are based on a combination of adapted versions of three previous data structures, namely, the constrained Delaunay pyramid, the line generalisation tree and the fixed grid. The second specific problem addressed in this thesis has been the development of an integrated multi-scale 3-D geological data model, for use within a Geoscientific Information System. This has resulted in a data storage scheme which enables the integration of terrain data, geological outcrop data and borehole data at various levels of detail. The thesis also presents details of prototype database implementations of each of the new data storage schemes. These implementations have served to demonstrate the feasibility and benefits of an integrated multi-scale approach. The research has also brought to light some areas that will need further research before fully functional systems are produced. The final chapter contains, in addition to conclusions made as a result of the research to date, a summary of some of these areas that require future work.
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Yang, Zhao. "Spatial Data Mining Analytical Environment for Large Scale Geospatial Data." ScholarWorks@UNO, 2016. http://scholarworks.uno.edu/td/2284.
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Nowadays, many applications are continuously generating large-scale geospatial data. Vehicle GPS tracking data, aerial surveillance drones, LiDAR (Light Detection and Ranging), world-wide spatial networks, and high resolution optical or Synthetic Aperture Radar imagery data all generate a huge amount of geospatial data. However, as data collection increases our ability to process this large-scale geospatial data in a flexible fashion is still limited. We propose a framework for processing and analyzing large-scale geospatial and environmental data using a “Big Data” infrastructure. Existing Big Data solutions do not include a specific mechanism to analyze large-scale geospatial data. In this work, we extend HBase with Spatial Index(R-Tree) and HDFS to support geospatial data and demonstrate its analytical use with some common geospatial data types and data mining technology provided by the R language. The resulting framework has a robust capability to analyze large-scale geospatial data using spatial data mining and making its outputs available to end users.
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Alani, Harith. "Spatial and thematic ontology in cultural heritage information systems." Thesis, University of South Wales, 2001. https://pure.southwales.ac.uk/en/studentthesis/spatial-and-thematic-ontology-in-cultural-heritage-information-systems(445b4484-9979-4653-a895-555432b789d7).html.
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This project investigated the design and implementation of a knowledge-based system for thematic and spatial access to information about archaeological artefacts. The project explored the use of an integrated spatial and thematic ontology to address many problems related to the search and retrieval of archaeological information. One common problem is the frequent mismatch between the terminology employed by users to access the information, and that used by developers to index it. Systems may lack the capability to process queries with loose information demand, since they are unable to imprecisely match query terms. Another challenging area is that of handling the spatial information associated with archaeological artefacts. Places normally have different version of names, often change in size, boundaries, and centroid coordinates. Generating appropriate spatial footprints to adequately represent their extents and infer their spatial relationships forms another challenging area. Several methods and approaches were investigated in this project to overcome the above problems. The ontology was designed to handle different versions of place names and ease the terminology problem by controlling vocabulary using integrated spatial and thematic thesauri. Semantic distance measures were employed to imprecisely match query terms, providing ranked lists of similar objects. A thematic measure was developed based on semantic-path traversals to expand artefact types. The project explored some of the main issues affecting the use of associative thesaurus relationships in query expansion. One approach found useful was to specialise these relationships and select which ones to activate based on the query context. The spatial domain in the ontology was constructed from a geographical thesaurus, enriched with spatial relationships. Spatial distance measures were used to provide more flexible retrieval for queries with spatial content. The two main spatial measures developed in this project were based on some of the common spatial information provided by most gazetteers, such as centroid coordinates and administrative hierarchies. Place co-ordinates were used to measure similarity of places according to Euclidean distances, while the hierarchical associations of places were useful to measure place similarity when administrative divisions are important or when co-ordinates are not available. A dynamic spatial approximation method was developed that uses sparse spatial information to generate approximated boundaries, and can be employed to infer topological, proximity, and directional information.
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Holter, Bengt. "Adaptive coded modulation in spatial and multiuser diversity systems." Doctoral thesis, Norwegian University of Science and Technology, Department of Electronics and Telecommunications, 2005. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-1724.
Full textAbstract:
This thesis consists of five included papers plus an introduction. The majority of the papers are devoted to performance analysis of an adaptive coded modulation (ACM) scheme based on multidimensional trellis codes. Primarily, single-user systems exploiting spatial diversity are analysed, but results are also presented for a multiuser system exploiting multiuser diversity.
The performance of the ACMscheme is evaluated for slowly flat-fading channels. When spatial diversity is exploited at the receiver end only, the analysis is focused on two different combining techniques: maximum ratio combining (MRC) and switched combining. Amultiple-inputmultiple-output (MIMO) diversity system is also considered, in which case the combined effect of both transmit and receive diversity is realized by using space-time block coding at the transmitter.
For wireless systems using spatial diversity, it is of interest to employ measures which can capture and quantify the performance improvement related to a reduced fading level. In this thesis, ameasure called the amount of fading (AF) is used to characterize the behavior of the error rate curve at a high signal-to-noise ratio (SNR). In particular, closed-form expressions for the AF at the output of a MIMO diversity system are provided, and it is shown that for a constant correlation model, the average symbol error probability at high SNRs may be expressed in terms of the AF.
Finally, a set of switched multiuser access schemes are proposed based on switched diversity algorithms originally devised to select between antennas in a spatial diversity system. ACM is used on each selected link to ensure a high spectral efficiency of the system.