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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Essays on spatial dynamic panel data model theories and applications /

Yu, Jihai, January 2007 (has links)
Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 175-178).
42

Conjugate hierarchical models for spatial data an application on an optimal selection procedure /

McBride, John Jacob. Bratcher, Thomas L. January 2006 (has links)
Thesis (Ph.D.)--Baylor University, 2006. / Includes bibliographical references (p. 77-81).
43

Bayesian semiparametric spatial and joint spatio-temporal modeling

White, Gentry, January 2006 (has links)
Thesis (Ph.D.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (May 2, 2007) Vita. Includes bibliographical references.
44

Integrated Spatial Reasoning in Geographic Information Systems: Combining Topology and Direction

Sharma, Jayant January 1996 (has links) (PDF)
No description available.
45

Towards a coastal spatial decision support system for multiple-use management

Canessa, Rosaline Regan 01 August 2018 (has links)
The coast is subject to increasing pressure from a multitude of often competing users. Coastal managers are faced with the challenge of balancing the distribution and activities of users. They must take into account user conflicts, environmental impacts, socioeconomic benefits, and the voices of the coastal community. On another stream. Geographic Information Systems (GIS) are being heralded as decision support tools. These tools range from inventory warehouses to dedicated Spatial Decision Support Systems (SDSS) to impending Collaborative Spatial Decision Making Systems (CSDMS) for decision-making groups. This research investigated the marriage of these two fields, coastal management and GIS, through the development and pilot implementation of a Coastal SDSS for multiple-use management. The investigation was pursued by exploring the component parts of a Coastal SDSS: (1) the decision makers and process within which they function; (2) the analysis upon which decisions are made; and (3) the data which are analysed and in themselves contribute to an understanding of the decision problem and solution. Information and observations for each of these components were gathered and woven together from five sources: (1) literature survey; (2) a two-phase questionnaire of coastal decision makers; (3) interviews of participants of a resource management multi-stakeholder process; (4) non-participant observation of an ongoing coastal management process; and (5) two workshops involving the pilot implementation of a Coastal SDSS to evaluate its effectiveness for group-based coastal management. The workshops, involving members from eight stakeholder groups, formed part of a current coastal management initiative in Barkley Sound, Vancouver Island. The pilot Coastal SDSS was programmed in Arclnfo™. It included the development of position analysis and multi-criteria analysis models accessed from a customised interface. The results from the workshops were assimilated with previous findings into design and implementation specifications of a Coastal SDSS. Twenty-one specifications are made for the development and implemention of a Coastal SDSS under categories of: 1) format; 2) decision making; 3) analysis; and 4) data. A chauffeur-driven system is advocated as the preferred format of implementation directed by a GIS facilitator and GIS analyst. Of critical importance to the successful implementation of a Coastal SDSS is adequate preparation of technical accessibility for participants. The decision making approach of a Coastal SDSS should lie in the generation and evaluation of alternatives with an emphasis on graphic communication and dynamic decision making. The analytical component of a Coastal SDSS must balance quantitative analysis with qualitative, and deterministic with interactive. Analytical specifications recommended include capability analysis, spatial coincidence, multi-criteria analysis, consensus evaluation, alternative evaluation, environmental modelling and generic GIS functionality. The points of emphasis for the data component include a taxonomy of coastal inventory with particular reference to coastal use and administrative framework, representation of the coast as a continuous transition zone between marine and terrestrial environments, cartographic communication geared towards decision making, and a metadata strategy for managing data quality. This research concludes that Coastal SDSS can fill a void in and enhance coastal management particularly with respect to supporting communication and objective spatial analytical methods. However, decision makers were cautious in embracing a central role for Coastal SDSS. Their concerns can be addressed by involving the full range of coastal decision makers in the design and development of Coastal SDSS particularly through experimental research design and by incorporating GIS into coastal management curricula. / Graduate
46

Model-free tests for isotropy, equal distribution and random superposition in spatial point pattern analysis

Wong, Ka Yiu 31 August 2015 (has links)
This thesis introduces three new model-free tests for isotropy, equal distribution and random superposition in non-rectangular windows respectively. For isotropy, a bootstrap-type test is proposed. The corresponding test statistic assesses the discrepancy between the uniform distribution and the empirical normalised reduced second-order moment measure of a sector of fixed radius with increasing central angle. The null distribution of the discrepancy is then estimated by stochastic reconstruction, which generates bootstrap-type samples of point patterns that resemble the spatial structure of the given pattern. The new test is applicable for small sample sizes and is shown to have more robust powers to different choices of user-chosen parameter when compared with the asymptotic chi-squared test by Guan et al. (2006) in our simulation. For equal distribution, a model-free asymptotic test is introduced. The proposed test statistic compares the discrepancy between the empirical second-order product densities of the observed point patterns at some pre-chosen lag vectors. Under certain mild moment conditions and a weak dependence assumption, the limiting null distribution of the test statistic is the chi-squared distribution. Simulation results show that the new test is more powerful than the permutation test by Hahn (2012) for comparing point patterns with similar structures but different distributions. The new test for random superposition is a modification of the toroidal shift test by Lotwick and Silverman (1982). The idea is to extrapolate the pattern observed in a non-rectangular window to a larger rectangular region by the stochastic reconstruction so that the toroidal shift test can be applied. Simulation results show that the powers of the test applied to patterns with extrapolated points are remarkably higher than those of the test applied to the largest inscribed rectangular windows, with only slightly increased type I error rates. Real data sets are used to illustrate the advantages of the tests developed in this thesis over the existing tests in the literature.
47

Complete spatial randomness tests, intensity-dependent marking and neighbourhood competition of spatial point processes with applications to ecology

Ho, Lai Ping 01 January 2006 (has links)
No description available.
48

Topology-inspired probabilistic path replanning in dynamic environments

Fisher, Richard January 2018 (has links)
A thesis submitted to the Faculty of Science, University of the Witwatersrand, in fulfilment of the requirements for the degree of Master of Science, 2018 / Path replanning in high dimensional dynamic environments is critical to the success of interactive and reactive robotic agents. State of the art replanning algorithms typically extend sampling-based methods such as rapidly-exploring random trees (RRT) or probabilistic roadmaps (PRM). However, the speed of replanning in complex configuration spaces is relatively slow, which limits the effectiveness of robotic agents in highly dynamic environments. This thesis proposes DRM-connect, a novel generalisation of the PRM and RRT-connect algorithms, which carries out replanning in dynamic environments by executing graph searches over an underlying graph G, using lazy collision checking. If a path through the graph is not found, DRM-connect will repair the graph using a novel extension to RRT-connect, which we call PRM-connect. Additionally, we investigate using an approximate Reeb graph as the underlying graph G, which attempts to capture the underlying topology of the task manifold from prior experience. DRM-connect is tested with both a Reeb graph and na¨ıve graph in a 2-D domain and compared to RRT, while DRMconnect with a Reeb graph is tested in three 7-D domains, and compared to RRT-connect. Through simulation we show that the combination of DRM-connect and a Reeb graph typically outperforms both RRT/RRT-connect and DRM-connect with a na¨ıve graph in terms of replanning times, with minimal impact on the length of the solution path. / XL2019
49

Nearest neighbor queries in spatial and spatio-temporal databases /

Zhang, Jun. January 2003 (has links)
Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2003. / Includes bibliographical references (leaves 125-131). Also available in electronic version. Access restricted to campus users.
50

SPATIAL VISUALIZATION ABILITY: EFFECTS OF LONG TERM PRACTICE AND RELATIONSHIP TO MATHEMATICAL ABILITY.

JOHNSON, MARGARET AKERS. January 1983 (has links)
This investigation was designed to test a hypothesis formulated by Julia Sherman (1967) concerning the development of spatial visualization and mathematic skills. The intention of the study was to examine the influence of early physical training on spatial visualization and mathematic skills, to determine whether intensive training in spatial relations would have a differential impact on male/female spatial performance and to gather information concerning the relationship between spatial visualization and mathematic performance. The investigation was divided into three studies and used 166 college students as subjects. Study one examined the impact of long term physical training, gymnastics, on spatial visualization and mathematic scores of two matched-groups selected from 99 subjects. The two groups, gymnast and control, each consisted of 28 subjects (14 males and 14 females) and were matched on IQ score, age, ethnic group, socioeconomic status, parental and sex-role identification, achievement motivation and years of training in other sports. Gymnasts averaged 5.5 years of gymnastic training: the control group had none. Study two examined spatial visualization scores obtained by 67 architectural students (49 males and 18 females) before and after a semester's training in spatial relations. Study three compared scores obtained by all 166 subjects on the Shepard Metzler Mental Rotation Test and a mathematic test derived from the Otis Test of Mental Abilities. The test of the hypothesis relating to the influence of early physical training on spatial and mathematic performance was not successful as the training of the gymnasts did not extend to early childhood. While significant sex-related differences favoring males were found in spatial performance, the amount of variance in spatial scores accounted for by sex was small, only 8%. No significant sex-related differences in mathematic performance were found. In study two, both males and females significantly improved spatial performance following training, but females did not demonstrate a significantly greater rate of improvement as predicted. The results of the third study indicated a moderate positive relationship between spatial and mathematic performance, however, no evidence was found to support a direct causal relationship between spatial skill and mathematic performance.

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