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1
Barr, Christopher David. "Applications of Voronoi tessellations in point pattern analysis." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1619485521&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Umande, Philip Pembe. "Spatial point pattern analysis with application to confocal microscopy data." Thesis, Imperial College London, 2008. http://hdl.handle.net/10044/1/8569.
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Wong, Ka Yiu. "Model-free tests for isotropy, equal distribution and random superposition in spatial point pattern analysis." HKBU Institutional Repository, 2015. https://repository.hkbu.edu.hk/etd_oa/202.
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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.
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Cromley, Gordon A. "Destroying the Jungle Republic: Counterinsurgency Theory and the Environment in South Vietnam (1967-1969)." Kent State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=kent1564697803934883.
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Barber, Michael R. "Effects of Hydraulic Dredging and Vessel Operation on Atlantic Sturgeon Behavior in a Large Coastal River." VCU Scholars Compass, 2017. http://scholarscompass.vcu.edu/etd/4792.
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The tidal James River, a focus of VCU's Atlantic Sturgeon program, supports both commercial shipping and hydraulic dredging. These anthropogenic threats present documented but preventable sources of mortality to the endangered species. Using three separate VEMCO Positioning System (VPS) receiver arrays, spatial data of previously-tagged fish were collected. ArcGIS and Programita software were used to analyze fish spatial distributions in the presence and absence of potential threats, using additional data including automatic identification system (AIS) vessel locations, vessel passages compiled using camera footage, and dredge records provided by the US Army Corps of Engineers. The data showed a change in distribution associated with vessels that varied according to river width but not vessel type. Dredging was associated with differences in spatial distribution, but more clearly for adults than sub-adults. The responses of Atlantic Sturgeon provide information necessary to propose potential threat mitigations, including seasonal restrictions for both vessels and dredging.
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SALVO, F. DI. "VARIAZIONE SPAZIALE DEL RISCHIO RELATIVO DI MORTE PER TUMORE DEL SISTEMA EMOLINFOPOIETICO, IN UN¿AREA PROSSIMA AD UNA RAFFINERIA PETROLIFERA." Doctoral thesis, Università degli Studi di Milano, 2014. http://hdl.handle.net/2434/232971.
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Kernel smoothing is a popular approach to estimating relative risk surface from data in the location of cases and controls in geographical epidemiology. To date, the use of a fixed smoothing parameter has dominated in literature, but it can perform poorly with highly heterogeneous population. A more intuitive approach is to utilize a spatially adaptive, variable smoothing parameter where the amount of smoothing depends inversely on the local amount of data. The interpretation of such surfaces is facilitated by plotting of tolerance contours which highlight areas where the risk is sufficiently high to reject the null hypothesis of unit relative risk. This approach has been applied to a epidemiological survey about the risk of death in the area surrounding an Italian petrochemical refinery where 172 deaths and 337 controls has been identified. Maps of the spatial variation of relative risk and tolerance contours have be produced. Only for women and those spending most of their time at home, we found a sub-region of elevated risk highlighted by plotted tolerance contours.
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Zhang, Weimin. "Topics in living cell miultiphoton laser scanning microscopy (MPLSM) image analysis." Texas A&M University, 2006. http://hdl.handle.net/1969.1/4412.
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Multiphoton laser scanning microscopy (MPLSM) is an advanced fluorescence
imaging technology which can produce a less noisy microscope image and minimize the
damage in living tissue. The MPLSM image in this research is the dehydroergosterol
(DHE, a fluorescent sterol which closely mimics those of cholesterol in lipoproteins and
membranes) on living cell's plasma membrane area. The objective is to use a statistical
image analysis method to describe how cholesterol is distributed on a living cell's
membrane. Statistical image analysis methods applied in this research include image
segmentation/classification and spatial analysis. In image segmentation analysis, we
design a supervised learning method by using smoothing technique with rank statistics.
This approach is especially useful in a situation where we have only very limited
information of classes we want to segment. We also apply unsupervised leaning methods
on the image data. In image data spatial analysis, we explore the spatial correlation of
segmented data by a Monte Carlo test. Our research shows that the distributions of DHE
exhibit a spatially aggregated pattern. We fit two aggregated point pattern models, an
area-interaction process model and a Poisson cluster process model, to the data. For the area interaction process model, we design algorithms for maximum pseudo-likelihood
estimator and Monte Carlo maximum likelihood estimator under lattice data setting. For
the Poisson Cluster process parameter estimation, the method for implicit statistical
model parameter estimate is used. A group of simulation studies shows that the Monte
Carlo maximum estimation method produces consistent parameter estimates. The
goodness-of-fit tests show that we cannot reject both models. We propose to use the area
interaction process model in further research.
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Hesselbarth, Maximilian H. K. [Verfasser], Kerstin [Akademischer Betreuer] Wiegand, Holger [Gutachter] Kreft, and Uta [Gutachter] Berger. "Analysing and modelling spatial patterns to infer the influence of environmental heterogeneity using point pattern analysis, individual-based simulation modelling and landscape metrics / Maximilian H. K. Hesselbarth ; Gutachter: Holger Kreft, Uta Berger ; Betreuer: Kerstin Wiegand." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2020. http://d-nb.info/1210264641/34.
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Ben, Cheikh Bassem. "Morphologie mathématique sur les graphes pour la caractérisation de l’organisation spatiale des structures histologiques dans les images haut-contenu : application au microenvironnement tumoral dans le cancer du sein." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066286/document.
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L'un des problèmes les plus complexes dans l'analyse des images histologiques est l'évaluation de l¿organisation spatiale des structures histologiques dans le tissu. En fait, les sections histologiques peuvent contenir un très grand nombre de cellules de différents types et irrégulièrement réparties dans le tissu, ce qui rend leur contenu spatial indescriptible d'une manière simple. Les méthodes fondées sur la théorie des graphes ont été largement explorées dans cette direction, car elles sont des outils de représentation efficaces ayant la capacité expressive de décrire les caractéristiques spatiales et les relations de voisinage qui sont interprétées visuellement par le pathologiste. On peut distinguer trois familles principales de méthodes des graphes utilisées à cette fin: analyse de structure syntaxique, analyse de réseau et analyse spectrale. Cependant, un autre ensemble distinctif de méthodes basées sur la morphologie mathématique sur les graphes peut être développé et adapté pour ce problème. L'objectif principal de cette thèse est le développement d'un outil capable de fournir une évaluation quantitative des arrangements spatiaux des structures histologiques en utilisant la morphologie mathématique basée sur les graphesOne of the most challenging problems in histological image analysis is the evaluation of the spatial organizations of histological structures in the tissue. In fact, histological sections may contain a very large number of cells of different types and irregularly distributed, which makes their spatial content indescribable in a simple manner. Graph-based methods have been widely explored in this direction, as they are effective representation tools having the expressive ability to describe spatial characteristics and neighborhood relationships that are visually interpreted by the pathologist. We can distinguish three main families of graph-based methods used for this purpose: syntactic structure analysis, network analysis and spectral analysis. However, another distinctive set of methods based on mathematical morphology on graphs can be additionally developed for this issue. The main goal of this dissertation is the development of a framework able to provide quantitative evaluation of the spatial arrangements of histological structures using graph-based mathematical morphology
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Catella, Samantha A. "Investigating herbaceous layer plant community patterns: when does abiotic complexity matter?" Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1559905264222712.
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Chen, Yan. "Spatial Analysis of Fatal Automobile Crashes in Nashville, TN, 2001-2011." TopSCHOLAR®, 2013. http://digitalcommons.wku.edu/theses/1300.
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With increasing levels of motor vehicle ownership, automobile crashes have become a serious public issue in the U.S. and around the world. Knowing when, where, and how traffic accidents happen is critical in order to ensure road safety and to plan for adequate road infrastructure. There is a rich body of literature pertaining to time-related fatal crashes, most of which focuses on non-spatial factors such as a driver’s visibility at night, drinking and drug use, and road conditions. These studies provide a theoretical basis for understanding the causes of crashes from a non-spatial perspective, and a number of traffic laws and policies consequently have been enacted to minimize the impacts of non-spatial factors. Over the past few years, advances in Geographic Information Systems (GIS) have greatly enhanced our ability to analyze traffic accidents from a spatial perspective. This study aims to fill a void in traffic safety studies by comparing and analyzing the differences in the spatial distribution of fatal crashes based on temporal factors, specifically in three periods: 1) day and night; 2) A.M. rush hours and P.M. rush hours; and 3) weekdays and weekends. With the Nashville Metropolitan Area as the study area, the research utilized a number of spatial point-pattern analysis (SPPA) methods, including planar KDE, planar global auto K function, network global cross K functions, and network local cross K functions. All fatal crashes in the Nashville area were found to be clustered and generally follow the patterns of average daily traffic flow. All time-based subtypes of fatal crashes also were found to be concentrated within the central urban area of Nashville, mostly along major roads, and especially near major road intersections and highway interchanges. No notable spatial differences were detected among the subtypes of fatal crashes when applying network global cross K function. However, with the help of the network local cross K function, some localized spatial differences were identified. Some specific locations of hotspots of nighttime and P.M. rush hour fatal crashes were found not to be at the same locations as those at of daytime and A.M. rush hour fatal crashes, respectively. The approach adopted in this study not only provides a new way to analyze spatial distribution of spatial point events such as fatal crashes, but it also can be applied readily to real-world applications. A good understanding of where these spatial differences are should help various agencies practice effective measures and policies in order to improve road conditions, reduce traffic accidents, and ensure road safety.
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Yogeswaran, Arjun. "3D Surface Analysis for the Automated Detection of Deformations on Automotive Panels." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/19992.
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This thesis examines an automated method to detect surface deformations on automotive panels for the purpose of quality control along a manufacturing assembly line.
Automation in the automotive manufacturing industry is becoming more prominent, but quality control is still largely performed by human workers. Quality control is important in the context of automotive body panels as deformations can occur along the assembly line such as inadequate handling of parts or tools around a vehicle during assembly, rack storage, and shipping from subcontractors. These defects are currently identified and marked, before panels are either rectified or discarded. This work attempts to develop an automated system to detect deformations to alleviate the dependence on human workers in quality control and improve performance by increasing speed and accuracy.
Some techniques make use of an ideal CAD model behaving as a master work, and panels scanned on the assembly line are compared to this model to determine the location of deformations. This thesis presents a solution for detecting deformations of various scales without a master work. It also focuses on automated analysis requiring minimal intuitive operator-set parameters and provides the ability to classify the deformations as dings, which are deformations that protrude from the surface, or dents, which are depressions into the surface.
A complete automated deformation detection system is proposed, comprised of a feature extraction module, segmentation module, and classification module, which outputs the locations of deformations when provided with the 3D mesh of an automotive panel. Two feature extraction techniques are proposed. The first is a general feature extraction technique for 3D meshes using octrees for multi-resolution analysis and evaluates the amount of surface variation to locate deformations. The second is specifically designed for the purpose of deformation detection, and analyzes multi-resolution cross-sections of a 3D mesh to locate deformations based on their estimated size. The performance of the proposed automated deformation detection system, and all of its sub-modules, is tested on a set of meshes which represent differing characteristics of deformations in surface panels, including deformations of different scales. Noisy, low resolution meshes are captured from a 3D acquisition, while artificial meshes are generated to simulate ideal acquisition conditions. The proposed system shows accurate results in both ideal situations as well as non-ideal situations under the condition of noise and complex surface curvature by extracting only the deformations of interest and accurately classifying them as dings or dents.
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Mamuse, Antony. "Spatial statistical estimation of undiscovered mineral endowment: case of komatiite-associated nickel sulphide resources, Kalgoorlie Terrane, Western Australia." Thesis, Curtin University, 2010. http://hdl.handle.net/20.500.11937/449.
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The Kalgoorlie Terrane of the Yilgarn Craton, Western Australia, containing about 60% (~11 Mt) of the world’s known komatiite-hosted nickel sulphide resources, is the world’s best studied and economically most important province for this mineral deposit type. Although increasingly mature in terms of nickel exploration, the Kalgoorlie Terrane is believed to contain significant additional undiscovered nickel endowment. Using the data-rich Kalgoorlie Terrane, this thesis develops a benchmark methodology that combines geological knowledge with spatial analysis and mathematical-statistical methods to estimate undiscovered nickel resources.In the proposed methodology, nickel sulphide deposits are considered realisations of stochastic mineralisation processes and are analysed within the following framework. Komatiites in the Kalgoorlie Terrane constitute the full sample space or the permissive tract. Disjoint, naturally bound individual komatiite bodies that make up the sample space are used as the spatial analysis units. Some komatiite bodies within the sample space contain nickel sulphide deposits (mineralised) and others do not (unmineralised). In this study, the most explored mineralised komatiite bodies constitute local control areas against which nickel resources in the less explored komatiite bodies can be assessed. The concept of local control areas is analogous to the concept of global control areas which are well explored parts of permissive areas for particular deposit types worldwide.Spatial point pattern analyses showed that the spatial distribution of mineralised komatiite bodies within the sample space is clustered. In contrast, nickel sulphide deposits in individual komatiite bodies are either randomly distributed or dispersed, and not clustered. This absence of deposit clustering within individual komatiite bodies indicates that the intensity of the deposit pattern of each komatiite body may be adequately expressed as deposit density (number of deposits per km[superscript]2). In global quantitative resource assessments, regression analysis of the well established power law relationship between deposit density and size of global control areas provides a robust method for estimating the number of deposits.In this study a power law relationship reminiscent of that in global models was found between the sizes of control areas and deposit density. In addition, this study establishes another power law relationship between nickel endowment density (nickel metal per km[superscript]2) and the sizes of control areas. Deposit and endowment density regression models based on the two power laws suggested that, respectively, 59 to 210 (mean 114) nickel sulphide deposits and 3.0 to 10.0 Mt (mean 5.5 Mt) nickel metal remained undiscovered in demonstrably mineralised komatiite bodies within the Kalgoorlie Terrane. More emphasis is placed on endowment density which may be more intrinsic to the Kalgoorlie Terrane than deposit density because deposit counts are confounded by definitional ambiguities emanating from orebody complexities. Thus the spatial pattern of mineral deposits may not coincide with the spatial pattern of mineral endowment as demonstrated by spatial centrographic analyses in this study.To estimate the amount of undiscovered nickel metal in the entire Kalgoorlie Terrane and not just in the demonstrably mineralised komatiite bodies, Zipf’s law was applied. According to Zipf’s law, the size of the largest deposit is twice the size of the second, thrice the size of the third, four times the fourth, and so on. Based on the currently known size of Mt. Keith deposit, the largest nickel sulphide deposit in the Kalgoorlie Terrane, Zipf’s law indicates that the terrane is nearly mature in terms of nickel exploration and contains only about 3.0 Mt nickel metal in undiscovered resources. The collective implication of the regression and Zipf’s law estimates is that in the Kalgoorlie Terrane, no significant nickel resources are likely to be contained in the known komatiites that are presently not demonstrably mineralised. However if, as widely speculated, the actual size of Mt. Keith deposit is about twice the currently known size, Zipf’s law predicts 10.0 Mt nickel metal in undiscovered nickel endowment for the Kalgoorlie Terrane. The additional 7.0 Mt undiscovered nickel metal endowment is attributed to opening up of a new exploration search space through deeper resource delineation, within an otherwise nearly mature terrane.
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Soale, Abdul-Nasah. "Spatio-Temporal Analysis of Point Patterns." Digital Commons @ East Tennessee State University, 2016. https://dc.etsu.edu/etd/3120.
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In this thesis, the basic tools of spatial statistics and time series analysis are applied to the case study of the earthquakes in a certain geographical region and time frame. Then some of the existing methods for joint analysis of time and space are described and applied. Finally, additional research questions about the spatial-temporal distribution of the earthquakes are posed and explored using statistical plots and models. The focus in the last section is in the relationship between number of events per year and maximum magnitude and its effect on how clustered the spatial distribution is and the relationship between distances in time and space in between consecutive events as well as the distribution of the distances.
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Bui, Manh Hung. "Structure and restoration of natural secondary forests in the Central Highlands, Vietnam." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-216210.
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Introduction and objectives
In Vietnam, the forest resources have been declining and degrading severely in recent years. The degradation has decreased the natural forest area, changed the forest structure seriously and reduced timber volume and biodiversity. From 1999 to 2005, the rich forest area has decreased 10.2%, whereas the poor secondary forest has increased dramatically by 20.7%. Forest structure plays an important role in forestry research. Understanding forest structure will unlock an understanding of the history, function and future of a forest ecosystem (Spies, 1998). The forest structure is an excellent basis for restoration measures. Therefore, this research is necessary to contribute to improving forest area and quality, reducing difficulties in forest management. The study also enhances the grasp of forest structure, structure changes after harvesting and fills serious gaps in knowledge. In addition, the research results will contribute to improving and rescuing the poor secondary forest and restoring it, approaching the old-growth forest in Vietnam.
Material and methods
The study was conducted in Kon Ka Kinh national park. The park is located in the Northeastern region of Gia Lai province, 50 km from Pleiku city center to the Northeast. The park is distributed over seven different communes in three districts: K’Bang, Mang Yang and Đăk Đoa. Data were collected from 10 plots of secondary forests (Type IIb) and 10 plots of primeval forests (Type IV). Stratified random sampling was applied to select plot locations. 1 ha plots were used to investigate gaps. 2000 m2 plots were used to measure overstorey trees such as diameter at breast height, total height, crown width and species names. 500 m2 subplots were used to record tree positions. For regeneration, 25 systematic 4 m2 subplots were established inside 1 ha plots. After data were collected in the field, data analyses were conducted by using R and Excel. Firstly, some stand information, such as density, volume and so on, was calculated, and then descriptive statistics were computed for diameter and height variables. Linear mixed effect models were applied to analyze the difference of diameter and height and to check the effect of random factor between the two forest types. Diameter and height frequency distributions were also generated and compared by using permutational analysis of variance (PERMANOVA). Non-linear regression models were analyzed for diameter and height variables. Similar analyses were implemented for gaps. Regarding spatial point patterns of overstorey trees, replicated point pattern analysis techniques were applied in this research. For biodiversity, some calculations were run such as richness and biodiversity indices, comparison of biodiversity indices by using linear mixed models and biodiversity differences between two forest types tested again by permutational analysis of variance. In terms of regeneration, some analyses were implemented such as: height frequency distribution generation, frequency difference testing, biodiversity indices for the regeneration and spatial distribution checking by using a nonrandomness index.
Results and discussion
After analyzing the data, some essential findings were obtained as follows: Hypothesis H1 “The overstorey structure of secondary forests is more homogeneous and uniform than old-growth forests” is accepted. In other words, the secondary forest density is about 1.8 times higher than the jungle. However, the volume is only 0.56 times as large. The average diameter and height of the secondary forest is smaller by 5.71 cm and 3.73 m than the old-growth forest, respectively. Linear mixed effect model results indicate that this difference is statistically different and the effect of the random factor (Section) is not important. Type IIb has many small trees and the diameter frequency distribution is quite homogeneous. The old-growth forest has more big trees. For both forest stages, the height frequency distribution is positively skewed. PERMANOVA results illustrate that the frequency distribution is statistically different between the two forest types. Regression functions are also more variant and diverse in the old-growth forest, because all standard deviations of the parameters are greater there. Gap analysis results indicate that the number of gaps in the young forest is slightly higher, while the average gap size is much smaller. The gap frequency distribution is statistically different between the two types. In terms of the spatial point pattern of overlayer trees, the G-test and the pair correlation function results show that trees distribute randomly in the secondary forest. In contrast, the spatial point patterns of trees are more regular and diverse in the old-growth forest. The spatial point pattern difference is not significant, and this is proved by a permutational t-test for pair correlation function (pcf). Envelope function results indicate that the variation of pcf in young forests is much lower than in the primary forests.
Hypothesis H2 “The overstorey species biodiversity of the secondary forest is less than in the old-growth forest” is rejected. Results show that the number of species of the secondary forest is much greater than in the old-growth forest, especially richness. The richness of the secondary forest is 1.16 times higher. The Simpson and Shannon indices are slightly smaller in the secondary forest. The average Simpson index for both forest stages is 0.898 and 0.920, respectively. However, the difference is not significant. Species accumulation curves become relatively flatter on the right, meaning a reasonable number of plots have been observed. Estimated number of species from accumulation curves in two forest types are 105 and 95/ha. PERMANOVA results show that number of species and proportion of individuals in each species are significantly different between forest types.
Hypothesis H3 “The number regenerating species of the secondary forest is less and they distribute more regularly, compared to the old-growth forest” is rejected. There are both similarities and differences between the two types. The regeneration density of the stage IIb is 22,930 seedlings/ha, greater than the old forest by 9,030 seedlings. The height frequency distribution shows a decreasing trend. Similar to overstorey, the richness of the secondary forest is 141 species, higher than the old-growth forest by 9 species. Biodiversity indices are not statistically different between two types. PERMANOVA results indicate that the number of species and the proportion of individuals for each species are also not significantly different from observed forest types. Nonrandomness index results show that the regeneration distributes regularly. Up to 95% of the plots reflect this distribution trend.
Hypothesis H4 “Restoration measures (with and without human intervention) could be implemented in the regenerating forest” is accepted. The investigated results show that the secondary forest still has mother trees, and it has enough seedlings to restore. Therefore, restoration solutions with and without human intervention can be implemented. Firstly, forest protection should be applied. This measure is relevant to national park regulations in Vietnam. Rangers and other related organizations will be responsible for carrying out protection activities. These activities will protect forest resources from illegal logging, grazing and tourist activities. Environmental education and awareness-raising activities for indigenous people is also important. Another measure is additional and enrichment planting. It should focus on exclusive species of the overstorey in Type IIb or exclusive species of the primary forest. Selection of these species will lead to species biodiversity increase in the future. This also meets the purpose of the maximum biodiversity solution.
Conclusion
Forest resources play a very important role in human life as well as maintaining the sustainability of ecosystems. However, at present, they are under serious threat, particularly in Vietnam. Central Highland, Vietnam, where forest resources are still relatively good, is also threatened by illegal logging, lack of knowledge of people and so on. Therefore, it needs the hands of the people, especially foresters and researchers. Through research, scientists can provide the knowledge and understanding of the forest, including the structure and forest restoration. This study has obtained important findings. The secondary forest is more homogeneous and uniform, while the old-growth forest is very diverse. Biodiversity of the overstorey in the secondary forest is more than the primary. The number of regenerating species in the secondary forest is higher, but other indices are not statistically different between two types. The regeneration distribute regularly on the ground. The secondary forest still has mother trees and sufficient regeneration, so some restoration measures can be applied here. Findings of the study contribute to improve people’s understanding of the structure and the structural changes after harvesting in Kon Ka Kinh national park, Gia Lai. That is a key to have better understandings of the history and values of the forests. These findings and the proposed restoration measures address rescuing degraded forests in Central Highland in particular and Vietnam in general. And further, this is a promising basis for the management and sustainable use of forest resources in the future.
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Wilson, Helen Elizabeth. "Statistical analysis of replicated spatial point patterns." Thesis, Lancaster University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268009.
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The field of pathology provides us with many opportunities for collecting replicated spatial data. Using an ordinary microscope, for example, we can digitise cell positions within windows imposed on pieces of tissue. Suppose now that we have some such replicated spatial data from several groups of individuals, where each point in each window represents a cell position. We seek to determine whether the spatial arrangement of cells differs between the groups. We propose and develop a new method which allows us to answer such questions, and apply it to some spatial neuro-anatomical data. We introduce point process theory, and extend the existing second order methods to deal with replicated spatial data. We conclude the first part of the thesis by defining Sudden Infant Death Syndrome (S.LD.S.) and Intra-Uterine Growth Retardation (LU.G.R.), and stating why these conditions are neuro-anato,mically interesting. We develop and validate a method for comparing groups of spatial data, which is motivated by analysis of variance, and uses a Monte Carlo procedure to attach significance to between-group differences. Having carried out our initial investigative work looking exclusively at the one-way set up, we extend the new methods to cope with two and higher way set ups, and again carry out some validation. We turn our attention to practical issues which arise in the collection of spatial neuroanatomical data. How, for example, should we collect the data to ensure the unbiasedness of any inference we may draw from it? We introduce the field of stereology which facilitates the unbiased sampling of tissue. We note a recent proposal to assess spatial distribution of cells using a stereological approach, and compare it with an existing second order method. We also note the level of structural heterogeneity within the brain, and consider the best way to design a sampling protocol. We conclude with a spatial analysis of cell position data, collected using our specified design, from normal birth-weight non S.LD.S., normal birth-weight S.I.D.S and low birth-weight S.LD.S cases.
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Doguwa, S. I. "Statistical analysis of mapped spatial point patterns." Thesis, University of Essex, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383379.
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Allié, Élodie. "Assemblage des communautés d’arbres à une échelle locale en forêt tropicale : Apport d’une approche intégrative." Thesis, Guyane, 2016. http://www.theses.fr/2016YANE0003/document.
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Les forêts tropicales représentent un ‘hotspot’ de diversité avec un nombre considérable d’espèces qui coexistent jusqu’à une échelle locale fine. Plus particulièrement, 16 000 espèces d’arbres coexistent en Amazonie, 1 800 en Guyane française et entre 120 et plus de 200 espèces d’arbres par hectare. Cependant, le maintien de cette diversité face aux changements globaux actuels et à venir (qu’ils soient anthropiques ou climatiques…) est incertain. Avant de pouvoir prédire l’évolution de la diversité face aux changements globaux, un travail fondamental est nécessaire afin de comprendre les processus d’assemblage des communautés, processus qui maintiennent cette diversité. Ce travail est réalisé depuis de nombreuses années en écologie et reste d’actualité vu l’absence de consensus quant à l’importance relative des processus d’assemblage. Cette thèse s’inscrit dans la continuité de ce travail fondamental en utilisant une approche intégrative innovante, qui aborde de manière multi-échelle trois types de diversité : diversité taxonomique, fonctionnelle et phylogénétique. Nos résultats questionnent sur l'importance du filtrage environnemental quant aux propriétés hydrologiques et chimiques des sols, et sur celle des interactions biotiques dans l’assemblage de la communauté étudiée. Par ailleurs, nos résultats suggèrent que les distributions d’espèces puissent être influencées par la dynamique forestière en lien avec les chutes d’arbres et donc avec la disponibilité en lumière. Enfin, nous avons mis en évidence l’importance de la limitation de dispersionTropical forests are a biodiversity hotspot, with the coexistence of numerous species until a fine spatial scale. Particularly, 16.000 tree species coexist in Amazonia, 1.800 in Frenche Guiana and between 120 and more than 200 tree species per hectare. However, there are some uncertainties in maintaining diversity in regard to global changes. Hence before predicting the diversity evolution face of global changes, fundamental studies are needed to understand which assembly processes are involved in the maintenance of diversity. These fundamental studies still relevant given the lack of consensus on the relative importance of assembly processes. This thesis is a continuation of these fundamental studies, using innovative integrative approach, at multi-scale, to address three types of diversity: taxonomic diversity, functional and phylogenetic. Our results challenge the importance of environmental filtering for hydrological and chemical properties of soils, versus the importance of biotic interactions on community assembly. Furthermore, our results suggest that species distributions could be affected by forest dynamics related to falling trees and therefore by light availability. Finally, we have highlighted the importance of dispersal limitation on community assembly
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Pereira, Sandra M. C. "Analysis of spatial point patterns using hierarchical clustering algorithms." University of Western Australia. School of Mathematics and Statistics, 2003. http://theses.library.uwa.edu.au/adt-WU2004.0056.
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[Formulae and special characters can only be approximated here. Please see the pdf version of the abstract for an accurate reproduction.] This thesis is a new proposal for analysing spatial point patterns in spatial statistics using the outputs of popular techniques of (classical, non-spatial, multivariate) cluster analysis. The outputs of a chosen hierarchical algorithm, named fusion distances, are applied to investigate important spatial characteristics of a given point pattern. The fusion distances may be regarded as a missing link between the fields of spatial statistics and multivariate cluster analysis. Up to now, these two fields have remained rather separate because of fundamental differences in approach. It is shown that fusion distances are very good at discriminating different types of spatial point patterns. A detailed study on the power of the Monte Carlo test under the null hypothesis of Complete Spatial Randomness (the benchmark of spatial statistics) against chosen alternative models is also conducted. For instance, the test (based on the fusion distance) is very powerful for some arbitrary values of the parameters of the alternative. A new general approach is developed for analysing a given point pattern using several graphical techniques for exploratory data analysis and inference. The new strategy is applied to univariate and multivariate point patterns. A new extension of a popular strategy in spatial statistics, named the analysis of the local configuration, is also developed. This new extension uses the fusion distances, and analyses a localised neighbourhood of a given point of the point pattern. New spatial summary function and statistics, named the fusion distance function H(t), area statistic A, statistic S, and spatial Rg index, are introduced, and proven to be useful tools for identifying relevant features of spatial point patterns. In conclusion, the new methodology using the outputs of hierarchical clustering algorithms can be considered as an essential complement to the existing approaches in spatial statistics literature.
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Stanford, Derek C. "Fast automatic unsupervised image segmentation and curve detection in spatial point patterns /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/8976.
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Bauman, David. "Analyses spatialement explicites des mécanismes de structuration des communautés d'arbres." Doctoral thesis, Universite Libre de Bruxelles, 2018. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/276814.
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La compréhension des processus écologiques qui sous-tendent l’assemblage des communautés végétales et la coexistence des espèces est un objectif central en écologie. Ces processus sont potentiellement nombreux et de natures contrastées. Ainsi, la composition d’une communauté de plantes dépend de processus déterministes liés aux conditions environnementales abiotiques (climat, conditions physiques et chimiques du sol, lumière) et d’interactions biotiques complexes, positives (facilitation, symbioses) comme négatives (compétition, prédation, pathogènes). En outre, les communautés sont influencées par des processus stochastiques (capacité de dispersion limitée, dérive écologique). Si les mécanismes à l’origine de ces processus sont très différents, ils ont néanmoins en commun la génération de motifs (patterns) spatiaux de distribution d’espèces dans les communautés. L’analyse de la structure spatiale des communautés permet ainsi une étude indirecte des processus régissant les communautés. La nature complexe de ces patterns spatiaux a mené au développement de nombreuses méthodes statistiques de détection et de description de patterns. Les méthodes basées sur des vecteurs propres spatiaux sont parmi les plus puissantes et précises pour détecter des patterns complexes et multi-échelles. Ces vecteurs propres, utilisés comme prédicteurs spatiaux, peuvent être combinés à un ensemble de variables environnementales dans un cadre de partition de variation. Celui-ci permet, en théorie, de démêler les effets uniques et l’effet conjoint des variables environnementales et spatiales sur la variation de composition d’une communauté. Il mène ainsi à une quantification de l’action des processus déterministes et des processus stochastiques sur l’assemblage de la communauté. Néanmoins, je montre dans cette thèse qu’un certain flou méthodologique concernant deux étapes déterminantes des analyses basées sur les vecteurs propres spatiaux a mené une proportion élevée d’études à utiliser ces méthodes de manière sous-optimale, voire fortement biaisée. Ceci compromet la fiabilité des patterns spatiaux détectés et des processus écologiques inférés. Une autre limitation de ce cadre d’analyse concerne la fraction de la partition de variation décrivant l’effet environnemental spatialement structurés qu’aucune méthode ne permet de tester.Cette thèse présente des solutions non biaisées, puissantes et précises à ces différentes limitations méthodologiques et permet d’élargir le cadre de l’inférence de processus écologique à partir de patterns spatiaux de communautés. Les différentes étapes d’amélioration de ces méthodes ont également été illustrées dans la thèse au travers de trois cas d’études fournis par deux communautés d’arbres tropicale et tempérée et une communauté de champignons symbiotiques des arbres.Doctorat en Sciences
info:eu-repo/semantics/nonPublished
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MORGERA, ANDREA. "Dominant points detection for shape analysis." Doctoral thesis, Università degli Studi di Cagliari, 2012. http://hdl.handle.net/11584/266073.
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The growing interest in recent years towards the multimedia and the large amount of information exchanged across the network involves the various fields of research towards the study of methods for automatic identification. One of
the main objectives is to associate the information content of images, using techniques for identifying composing objects. Among image descriptors, contours reveal are very important because most of the information can be extracted
from them and the contour analysis offers a lower computational complexity also. The contour analysis can be restricted to the study of some salient points with high curvature from which it is possible to reconstruct the original contour. The thesis is focused on the polygonal approximation of closed digital curves. After an overview of the most common shape descriptors, distinguished between
simple descriptors and external methods, that focus on the analysis of boundary points of objects, and internal methods, which use the pixels inside the object also, a description of the major methods regarding the extraction of dominant points studied so far and the metrics typically used to evaluate the goodness of the polygonal approximation found is given. Three novel approaches to the
problem are then discussed in detail: a fast iterative method (DPIL), more suitable for realtime processing, and two metaheuristics methods (GAPA, ACOPA) based on genetic algorithms and Ant Colony Optimization (ACO), more com-
plex from the point of view of the calculation, but more precise. Such techniques are then compared with the other main methods cited in literature, in order to
assess the performance in terms of computational complexity and polygonal approximation error, and measured between them, in order to evaluate the robustness with respect to affine transformations and conditions of noise. Two
new techniques of shape matching, i.e. identification of objects belonging to the same class in a database of images, are then described. The first one is based on the shape alignment and the second is based on a correspondence by ACO, which puts in evidence the excellent results, both in terms of computational time and recognition accuracy, obtained through the use of dominant points. In the first matching algorithm the results are compared with a selection of dominant points generated by a human operator while in the second the dominant points are used instead of a constant sampling of the outline typically used for
this kind of approach.
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Khatun, Mahmuda. "Interpolation and extrapolation of point patterns based on variation analysis on measures." Thesis, University of Strathclyde, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502280.
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Suppose that we observe a point pattern in an observation window W₀ C Rd. In this study we pose ourselves the following two main questions: How can one extend the pattern in a 'reasonable way' to a larger window W ) W₀? Can one predict possible gaps in the observed point pattern where points were 'expected' but somehow failed to realise. We address these questions by assuming that the point pattern is an observed part of a realisation of a non-homogeneous Poisson process in W and estimate its intensity so that to mimic a given distributional characteristic of the pattern, for instance, its sample nearest neighbour distribution. The project aims to develop prediction and extrapolation techniques for random points processes and related techniques of optimisation of functionals depending on a measure. Applications are numerous and important, including restoration of images, detection of impurities in material science, prediction of anomalies in geology, etc.
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Eckel, Stefanie. "Statistical analysis of spatial point patterns - applications to economical, biomedical and ecological data." [S.l. : s.n.], 2008. http://nbn-resolving.de/urn:nbn:de:bsz:289-vts-66022.
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Cosma, Marta. "Stratal patterns and sedimentary facies in tidal point bars." Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3422690.
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Tidal channels play a key role in the evolution of coastal environments and commonly dominate tidal landscapes. These channels commonly show a clear meandering pattern which shapes the architectural geometries of sedimentary successions accumulated in tidal coastal realms. Nevertheless, a limited number of studies analysed the morphodynamic evolution of tidal meanders and the related point bar sedimentary bodies, whose internal architecture and sedimentary facies distribution remain still poorly explored, as highlighted by their scarce documentation in the rock record. The capability of reading the signature of tidal processes in sedimentary successions represents a powerful tool for paleo-environmental reconstructions. Detecting tidal channel deposits will contribute to studies on Holocene deposits and ancient rocks, with implications spanning from adaptation of natural systems to anthropic pressure to subsurface exploration for georesources. The present work aims at improving our understanding of the relationship between the evolution of tidal meander bends and the related sedimentary products, through the investigation of different research issues (RI), including: i) the influence of vertical aggradation and substrate compaction in shaping geometries of tidal point bars (RI1); ii) the reconstruction of three-dimensional architecture of tidal point bars, through a numerical modelling approach, developed under different aggradational conditions and planform transformation styles (RI2); iii) the relationship between mechanisms of bar growth and internal facies arrangements (RI3); and iv) the analysis of piracy-controlled geometries of point bar bodies (RI4). These research issues have been carried out in different tidal settings, including microtidal (Venice Lagoon, Italy – RI1, 2, and 4) and macrotidal (Bay of Mont Saint Michel, France – RI3) environments; both in modern (RI1, 2, 3, and 4) and ancient record (Eocene deposits of the Tremp-Graus Basin, Spain – RI4). A multidisciplinary approach has been adopted for modern examples, with different methodologies encompassing remote sensing techniques (i.e. historical aerial photos and LiDAR topographic time-series analysis), geomorphological field observations, sedimentary core analysis, and 3D forward stratigraphic modelling. The analysis of the ancient case study examples relies on classical outcrop sedimentology approach, which included line-drawing of photomosaics, bed-by-bed logging, and collection of paleo-flow measurements.
The main results from this work highlighted that:
I) geometries of tidal point bars can vary following aggradational conditions of surrounding overbank areas, along with changes in local accommodation space and channel discharge. These are, in turn, influenced by differential substrate compaction and channel network evolution;
II) 3D geometries of point bars developed by slowly migrating tidal channels under aggradational conditions, differ from tabular bodies envisaged by traditional point bar models. Indeed, their geometries are shaped by the planform and vertical shift of channel bends;
III) tidal meanders can expand alternating accretionary stages along seaward and landward side of point bars. In this contest, large amounts of mud-rich deposits are stored in their axial zone, where rhythmic tidal deposition is better recorded;
IV) occurrence of densely-drained tidal networks prevents channel bends to freely meander and causes interaction with adjacent channels triggering piracies. These piracies cause premature deactivation of sinuous channels and hinder the development of laterally extensive point bar bodies.
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González, Monsalve Jonatan A. "Statistical tests for comparisons of spatial and spatio-temporal point patterns." Doctoral thesis, Universitat Jaume I, 2018. http://hdl.handle.net/10803/462034.
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We mainly introduce a new set of tests to compare functional descriptors in point processes context. Firstly, since the study of spatio-temporal point processes has not been widely covered in the literature, a complete review is made. The review is a reference paper of the available techniques and approaches regarding the spatio-temporal context. Secondly, a studentized permutation test is developed in the spatio-temporal case. This test is motivated by locations of tornadoes in the U.S. in a period of 36 years. Some tools have been developed as a non-separable estimator of the first-order intensity, which allows a realistic analysis of the phenomenon through the new test.
Finally, a factorial two-way design is considered, where the observations are spatial point patterns in presence of replication. This methodology is motivated by a minerals engineering experiment. We develop statistics to test the influence of the factors and the possible interaction effects.Desarrollamos un nuevo conjunto de pruebas para comparar descriptores funcionales en el contexto de procesos puntuales. Puesto que el estudio de los procesos puntuales espacio-temporales no ha sido muy exhaustivo en la literatura, hemos hecho un artículo de resumen. Introducimos un test de permutación para grupos de patrones puntuales espacio-temporales motivado por las ubicaciones de ocurrencias de tornados en EE.UU. durante 36 años. Hemos desarrollado algunas técnicas como la estimación de la intensidad de primer-orden sin suponer separabilidad, lo que permite un tratamiento más realista del fenómeno climático en sí mismo a través del nuevo test.Finalmente, hemos desarrollado algunas técnicas para el análisis de la varianza de experimentos de dos factores en presencia de réplicas cuando las observaciones son patrones puntuales espaciales. Esta metodología está motivada por un experimento de ingeniería de minerales. Desarrollamos algunos estadísticos adecuados para probar la influencia de los factores y su posible interacción.
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Dorai-Raj, Sundardas Samuel. "First- and Second-Order Properties of Spatiotemporal Point Patterns in the Space-Time and Frequency Domains." Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/28540.
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Point processes are common in many physical applications found in engineering and biology.
These processes can be observed in one-dimension as a time series or two-dimensions as a spatial point pattern with extensive amounts of literature devoted to their analyses.
However, if the observed process is a hybrid of spatial and temporal point process, very few practical methods exist.
In such cases, practitioners often remove the temporal component and analyze the spatial dependencies.
This marginal spatial analysis may lead to misleading results if time is an important factor in the process.
In this dissertation we extend the current analysis of spatial point patterns to include a temporal dimension.
First- and second-order intensity measures for analyzing spatiotemporal point patterns are explicitly defined.
Estimation of first-order intensities are examined using 3-dimensional smoothing techniques.
Conditions for weak stationarity are provided so that subsequent second-order analysis can be conducted.
We consider second-order analysis of spatiotemporal point patterns first in the space-time domain through an extension of Ripley's $K$-function.
An alternative analysis is given in the frequency domain though construction of a spatiotemporal periodogram.
The methodology provided is tested through simulation of spatiotemporal point patterns and by analysis of a real data set.
The biological application concerns the estimation of the homerange of groups of the endangered red-cockaded woodpecker in the Fort Bragg area of North Carolina.
Monthly or bimonthly point patterns of the bird distribution are analyzed and integrated over a 23 month period.Ph. D.
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Peyton, Justin Tyler. "Methods for the Analysis of Developmental Respiration Patterns." Digital Commons @ East Tennessee State University, 2008. https://dc.etsu.edu/etd/1931.
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This thesis looks at the problem of developmental respiration in Sarcophaga crassipalpis Macquart from the biological and instrumental points of view and adapts mathematical and statistical tools in order to analyze the data gathered. The biological motivation and current state of research is given as well as instrumental considerations and problems in the measurement of carbon dioxide production. A wide set of mathematical and statistical tools are used to analyze the time series produced in the laboratory. The objective is to assemble a methodology for the production and analysis of data that can be used in further developmental respiration research.
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Loguercio, Salvatore. "Reductionist and Integrative approaches to explore the H.pylori genome." Doctoral thesis, Università degli studi di Padova, 2008. http://hdl.handle.net/11577/3425099.
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The reductionist approach of decomposing biological systems into their constituent parts has dominated molecular biology for half a century. Since organisms are composed solely of atoms and molecules without the participation of extraneous forces, it has been assumed that it should be possible to explain biological systems on the basis of the physico-chemical properties of their individual components, down to the atomic level. However, despite the remarkable success of methodological reductionism in analyzing individual cellular components, it is now generally accepted that the behavior of complex biological systems cannot be understood by studying their individual parts in isolation. To tackle the complexity inherent in understanding large networks of interacting biomolecules, the integrative viewpoint emphasizes cybernetic and systems theoretical methods, using a combination of mathematics, computation and empirical observation. Such an approach is beginning to become feasible in prokaryotes, combining an almost complete view of the genome and transcriptome with a reasonably extensive picture of the proteome.
Pathogenic bacteria are undoubtedly the most investigated subjects among prokaryotes. A paradigmatic example is the the human pathogen H.pylori, a causative agent of severe gastroduodenal disorders that infects almost half of the world population.
In this thesis, we investigated various aspects of Helicobacter pylori molecular physiology using both reductionist and integrative approaches.
In Section I, we have employed a reductionist, bottom-up perspective in studying the Cysteine oxidised/reduced state and the disulphide bridge pattern of an unusual GroES homolog expressed by H.pylori, Heat Shock protein A (HspA). This protein possesses a high Cys content, is involved in nickel binding and exhibits an extended subcellular localization, ranging from cytoplasm to cell surface. We have produced and characterized a recombinant HspA and mutants Cys94Ala and C94A/C111A. The disulphide bridge pattern has been assigned by integrating biochemical methodologies with mass spectrometry. All Cys are engaged in disulphide bonds that force the C-term domain to assume a peculiar closed loop structure, prone to host nickel ions. This novel Ni binding structural arrangement can be related to the Ni uptake/delivery to the extracellular urease, essential for the bacterium survival.
In Section II, we combined different computational methods with two main goals:
1) Analyze the H.pylori biomolecular interaction network in an attempt to select new molecular targets against H.pylori infection (Chapters 4 & 5);
2) Model and simulate the signaling perturbations induced by invading H.pylori proteins in the host ephitelial cells (Chapter 6).
Chapter 4 explores the 'robust yet fragile' feature of the H.pylori cell, viewed as a complex system in which robustness in response to certain perturbation is inevitably associated with fragility in response to other perturbations. With this in mind, we developed a general strategy aimed at identify control points in bacterial metabolic networks, which could be targets for novel drugs. The methodology is implemented on Helicobacter pylori 26695.
The entire metabolic network of the pathogen is analyzed to find biochemically critical points, e.g. enzymes which uniquely consume and/or produce a certain metabolite. Once identified, the list of critical enzymes is filtered in order to find candidate targets wich are non-homologous with the human enzymes. Finally, the essentiality of the identified targets is cross-validated by in silico deletion studies using flux-balance analysis (FBA) on a recent genome-scale metabolic model of H. pylori. Following this approach, we identified some enzymes which could be interesting targets for inhibition studies of H.pylori infection.
The study reported in Chapter 5 extends the previously described approach in light of recent theoretical studies on biological networks. These studies suggested that multiple weak attacks on selected targets are inevitably more efficient than the knockout of a single target, thus providing a conceptual framework for the recent success of multi-target drugs. We used this concept to exploit H.pylori metabolic robustness through multiple weak attacks on selected enzymes, therefore directing us toward target-sets discovery for combinatorial therapies.
We used the known metabolic and protein interaction data to build an integrated biomolecular network of the pathogen. The network was subsequently screened to find central elements of network communication, e.g. hubs, bridges with high betweenness centrality and overlaps of network communities. The selected enzymes were then classified on the basis of available data about cellular function and essentiality in an attempt to predict successful target-combinations. In order to evaluate the network effect triggered by the partial inactivation of candidate targets, robustness analysis was performed on small groups of selected enzymes using flux balance analysis (FBA) on a recent genome-scale metabolic model of H.pylori. In particular, the FBA simulation framework allowed to predict the growth phenotype associated to every partial inactivation set.
The preliminary results obtained so far may help to restrict the initial target-pool in search of target-sets for novel combinatorial drugs against H.pylori persistence. However, our long-term goal is to better understand the indirect network effects that lie at the heart of multi-target drug action and, ultimately, how multiple weak hits can perturb complex biological systems.
H.pylori produces various a cytotoxic protein, CagA, that interfere with a very important host signaling pathway, i.e. the epidermal growth factor receptor (EGFR) signaling network. EGFR signaling is one of the most extensively studied areas of signal transduction, since it regulates growth, survival, proliferation and differentiation in mammalian cells. In Chapter 6, we attempted to build an executable model of the EGFR-signaling core process using a process algebra approach. In the EGFR network, the core process is the heart of its underlying hour-glass architecture, as it plays a central role in downstream signaling cascades to gene expression through activation of multiple transcription factors. It consists in a dense array of molecules and interactions wich are tightly coupled to each other.
In order to build the executable model, a small set of EGFR core molecules and their interactions is tentatively translated in a BetaWB model. BetaWB is a framework for modelling and simulating biological processes based on Beta-binders language and its stochastic extension.
Once obtained, the computational model of the EGFR core process can be used to test and compare hypotheses regarding the principles of operation of the signaling network, i.e. how the EGFR network generates different responses for each set of combinatorial stimuli. In particular, probabilistic model checking can be used to explore the states and possible state changes of the computational model, whereas stochastic simulation (corresponding to the execution of the BetaWB model) may give quantitative insights into the dynamic behaviour of the system in response to different stimuli. Information from the above tecniques allows model validation through comparison within the experimental data available in the literature.
The inherent compositionality of the process algebra modeling approach enables further expansion of the EGFR core model, as well as the study of its behavior under specific perturbations, such as invading H.pylori proteins. This latter aspect might be of great value for H.pylori pathogenesis research, as signaling through the EGF receptors is intricately involved in gastric cancer and in many other gastroduodenal diseases.
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Adekile, Olusegun. "Object-oriented software development effort prediction using design patterns from object interaction analysis." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2329.
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Talanda, Ivan. "Optimalizace technologie výroby odlitků ze slitin Al metodou vytavitelného modelu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230150.
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Aim of this diploma thesis is to choose new pattern wax for Fimes a.s. foundry. New wax should substitute old not fully satisfactory pattern wax which caused problems in technological process resulting in increased number of rejects. New pattern wax should eliminate current problems and help foundry with producing large, thin-walled, high-quality castings. Numbers of pattern waxes supplied by world’s leading wax manufacturers were subjected to laboratory tests and pilot study. This diploma thesis is part of project Alfa TA01010766: „Research and development of production technology large, thin and high quality castings of aluminium alloys “
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Reva, Maria. "Computational approach to the study of neurotransmitter release." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS594.
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La transmission chimique synaptique permet la circulation de l'information dans le cerveau entre les neurones. Ce processus dépend essentiellement de la libération des neurotransmetteurs, qui est régie par une exocytose régulée par le calcium. La vitesse, l'efficacité et la fiabilité de la transmission synaptique sont affectées de façon critique par la dynamique spatio-temporelle du calcium et la distance que les ions Ca2+ parcourent pour atteindre le capteur vésiculaire. Nous émettons l'hypothèse que les variations dans l'organisation nanométrique des VGCC et des vésicules synaptiques contribuent à la diversité de la fonction synaptique. Toutefois, l'observation expérimentale directe de ce deuxième système fondamental de messagerie n'est pas possible à l'heure actuelle en raison de son échelle de temps submilliseconde et de son échelle spatiale submicronique. Par conséquent, nous avons adopté une approche analyique pour étudier la dynamique spatio-temporelle de la fusion vésiculaire déclenchée par le Ca2+. Au cours de ce travail, nous avons adapté des méthodes classiques de processus ponctuels et des modèles génératifs pour interpréter les différences dans les topographies canaux-vésicules des synapses cérébelleux faibles et forts. L'impact fonctionnel des arrangements déduits a été étudié plus en détail à l'aide de simulations de Monte Carlo (MC) de la dynamique du calcium et de la fusion vésiculaire, avec des paramètres limités expérimentalement. Nous avons constaté que de petites grappes de VGCC avec une distance de couplage étroite entre les canaux calciques et la vésicule peuvent expliquer les caractéristiques fonctionnelles des synapses fortes, tandis que la disposition où les VGCC sont couplés avec une distance plus lâche et exclus du voisinage de la vésicule peut reproduire le comportement des synapses faibles. Cela suggère donc que la distribution à l'échelle nanométrique des VGCC et des vésicules synaptiques diffère d'une synapse à l'autre et constitue un facteur clé de la diversité synaptique fonctionnelle. Nous avons aussi délimité les facteurs et paramètres critiques pour les simulations de l'évolution et de la probabilité de la libération des vésicules. Nous avons constaté que parmi les facteurs critiques figurent l'ouverture stochastique des canaux calciques, l'affinité du tampon endogène fixe et du capteur de vésicules, ainsi que la durée de l'entrée du calcium. Des simulations basées sur des particules d'une durée d'un mois ont motivé nos efforts pour explorer de nouvelles méthodes analytiques inspirées des méthodes de premier passage de champ moyen. Nous avons établi une distribution de probabilité d'un seul être lié au capteur. Le modèle a été validé à l'aide de simulations de Monte Carlo basées sur les particules. En raison de la nature de la méthode d'analyse, nous avons pu simuler la liaison des ions Ca2+ à un capteur entre les nanosecondes et les 100 millisecondes de temps de diffusion-réaction. Les calculs rapides effectués à l'aide de la méthode analytique se prêtaient beaucoup mieux à la recherche de paramètres et à la compréhension de l'interaction entre les constantes de marche et d'arrêt du capteur et les tampons concurrents. Ces simulations, par exemple, ont clairement montré que la constante de vitesse du tampon avait une influence critique sur l'évolution temporelle de l'occupation du capteur à l'échelle de la microseconde et de la milliseconde pour les paramètres de type expérimental, et qu'elle définissait également l'évolution temporelle de la fusion vésiculaire. Une fois que nous aurons surmonté certains des obstacles initiaux, cette nouvelle approche représentera la première approche analytique qui prédit la dynamique du profil spatio-temporel Ca2+ et la façon dont il conduit la fusion vésiculaire [...]Chemical synaptic transmission enables information flow in the brain between neurons. This process critically depends on neurotransmitter release, which is governed by calcium-regulated exocytosis. The speed, efficacy, and reliability of synaptic transmission are critically affected by the spatiotemporal calcium dynamics and the distance that Ca2+ ions travel to reach the vesicular sensor. We hypothesize that variations in the nanoscale organization of VGCCs and synaptic vesicles contribute to the diversity of synaptic function. However, direct experimental observation of this fundamental second messenger system is not currently possible due to its submillisecond timescale and submicron spatial scale. Therefore, we have taken a computational approach to study the spatiotemporal dynamics of Ca2+ -triggered vesicle fusion. In the course of this work, we have adapted classical point process methods and generative models to interpret differences in channel-vesicle topographies in the weak and strong cerebellar synapses. The function impact of inferred arrangements was further explored using Monte Carlo (MC) simulations of calcium dynamics and vesicular fusion, with experimentally constrained parameters. We found that small VGCC clusters with tight coupling distance between calcium channels and vesicle can account for the functional characterises of the strong synapses, while the arrangement where VGCCs are loosely coupled and excluded from the vicinity of the vesicle can reproduce the behaviour of weak synapses. Thus suggesting that nanoscale distribution of VGCCs and synaptic vesicles differs among synapses and is a key factor underlying functional synaptic diversity. Along the way, we have delineated critical factors and parameters for simulations of vesicle release time course and probability. We found that among the critical factors are the stochastic opening of the calcium channels, affinity of fixed endogenous buffer and vesicles sensor, as well as duration of calcium entry. Month-long particle-based simulations motivated our efforts to explore novel analytical methods inspired from mean-field first-passage methods. We have established a probability distribution of a single calcium ion being bound to the sensor. The model was validated using particle based Monte Carlo simulations. Because of the nature of the analytical method we were able to simulate the binding of Ca2+ ions to a sensor between nanoseconds to 100’s milliseconds of diffusion-reaction time. The rapid calculations using the analytical method were much more amenable to parameter searching and understanding how on and off-rate constants of the sensor and competing buffers interacted. These simulations, for example, showed clearly that the off-rate constant of the buffer critically influenced the time course of the sensor occupancy on the microsecond and millisecond time scale for experimental-like parameters, and in turn also define the time course of vesicle fusion. Once we surpass some of the initial hurdles, this novel approach will represent the first analytical-based approach that predicts spatial-temporal profile Ca2+ dynamics and how it drives vesicle fusion. We aspire to use this approach as a building block for a new, efficient diffusion reaction simulator of vesicle release, enhancing precision and accuracy while significantly reducing computational time
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Kong, Longbo. "Accurate Joint Detection from Depth Videos towards Pose Analysis." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1157524/.
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Joint detection is vital for characterizing human pose and serves as a foundation for a wide range of computer vision applications such as physical training, health care, entertainment. This dissertation proposed two methods to detect joints in the human body for pose analysis. The first method detects joints by combining body model and automatic feature points detection together. The human body model maps the detected extreme points to the corresponding body parts of the model and detects the position of implicit joints. The dominant joints are detected after implicit joints and extreme points are located by a shortest path based methods. The main contribution of this work is a hybrid framework to detect joints on the human body to achieve robustness to different body shapes or proportions, pose variations and occlusions. Another contribution of this work is the idea of using geodesic features of the human body to build a model for guiding the human pose detection and estimation. The second proposed method detects joints by segmenting human body into parts first and then detect joints by making the detection algorithm focusing on each limb. The advantage of applying body part segmentation first is that the body segmentation method narrows down the searching area for each joint so that the joint detection method can provide more stable and accurate results.
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Saeedimoghaddam, Mahmoud. "Exploring the Effectiveness of the Urban Growth Boundaries in USA using the Multifractal Analysis of the Road Intersection Points, A Case Study of Portland, Oregon." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1595847811169889.
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Speir, Cameron Lindsey. "Two Cost Analyses in Resource Economics: The Public Service Costs of Alternative Land Settlement Patterns and Effluent Allowance Trading in Long Island Sound." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/31154.
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This study offers two cost analyses to inform public policy decisions on the use of land and water resources. The first presents some public service costs associated with different spatial forms of land development. The second cost analysis presents costs associated with three different policy options for meeting water quality goals in Long Island Sound.
The objective the first analysis is to determine the cost to local governments of providing water distribution and wastewater collection services to alternative spatial forms of residential development. Components of spatial form are explicitly defined in terms of lot size, distance and tract dispersion. An engineering cost model is used to determine the water and sewer costs to three sets of hypothetical land settlement scenarios. Each set shows the effect of one component of spatial form on cost.
The results show that smaller lots, shorter distances between existing centers and less tract dispersion reduce public water and sewer costs. Lot size is found to have the most pronounced effect on water and sewer cost. Some policy options for reducing the public service costs associated with development are considered.
The objective of the second cost analysis is to analyze the cost implications of a nitrogen allowance trading system for wastewater treatment plants in Connecticut. Effluent allowance trading involves the transfer of pollution control responsibility between pollution sources. Effluent allowances are the right to discharge a given quantity of waste into the environment over a given time period. Allowance trading has been proposed as a way of reducing pollution control costs, encouraging innovative pollution prevention techniques and more quickly achieving water quality goals.
Long Island Sound, a major estuary in the northeastern United States, experiences chronically low dissolved oxygen levels. Excessive nitrogen loads from anthropogenic activities in the Sound watershed have been identified as the cause of the oxygen problem. The state of Connecticut is examining the possibility of introducing an effluent allowance trading system in order to reduce the cost of achieving required reductions in nitrogen discharge.
A linear programming model is used to predict trading outcomes and allowance prices. The total cost of achieving a nitrogen load cap is calculated under three administrative approaches. The first approach is a uniform reduction requirement where all plants are required to reduce discharge by the same proportion. The second approach is an administrative reallocation of waste load where a regulatory agency assigns control responsibility based on the agency's understanding of relative costs. The third approach is a flexible effluent allowance trading system. The results will show that a trading program offers cost savings over traditional regulatory approaches, demonstrate the potential for further cost savings from pollution prevention activities and estimate the cost savings that would result from including nonpoint sources in the overall nitrogen reduction strategy.
Master of Science
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Brown, Andrew D. "Looking Outward from the Village: The Contingencies of Soil Moisture on the Prehistoric Farmed Landscape near Goodman Point Pueblo." Thesis, University of North Texas, 2016. https://digital.library.unt.edu/ark:/67531/metadc862755/.
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Ancestral Pueblo communities of the central Mesa Verde region (CMVR) became increasingly reliant on agriculture for their subsistence needs during Basketmaker III (BMIII) through Terminal Pueblo III (TPIII) (AD 600–1300) periods. Researchers have been studying the Ancestral Pueblo people for over a century using a variety of methods to understand the relationships between climate, agriculture, population, and settlement patterns. While these methods and research have produced a well-developed cultural history of the region, studies at a smaller scale are still needed to understand the changes in farming behavior and the distribution of individual sites across the CMVR. Soil moisture is the limiting factor for crop growth in the semi-arid region of the Goodman Watershed in the CMVR. Thus, I constructed the soil moisture proxy model (SMPM) that is on a local scale and focuses on variables relevant to soil moisture – soil particle-size, soil depth, slope, and aspect. From the SMPM output, the areas of very high soil moisture are assumed to represent desirable farmland locations. I describe the relationship between very high soil moisture and site locations, then I infer the relevance of that relationship to settlement patterns and how those patterns changed over time (BMIII – TPIII). The results of the model and its application help to clarify how Ancestral Pueblo people changed as local farming communities. The results of this study indicates that farmers shifted away from use of preferred farmland during Terminal Pueblo III, which may have been caused by other cultural factors. The general outcome of this thesis is an improved understanding of human-environmental relationships on the local landscape in the CMVR.
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Menin, Aline. "eSTIMe : un environnement de visualisation pour l'analyse multi-points de vue des mobilités quotidiennes." Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALS010.
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Le domaine de recherche de la mobilité urbaine vise l'observation et la conception des déplacements humains dans un environnement urbain, dont les informations aident à la prise de décision et à la résolution de problèmes dans le cadre des politiques publiques. De nombreux experts - pas nécessairement spécialistes des transports - doivent traiter des données urbaines plus ou moins standardisées pour en extraire des connaissances synthétiques et facilement exploitables. De ce fait, les agences de transport public mènent couramment des enquêtes de déplacements pour recueillir des informations sur les déplacements quotidiens de la population sur un territoire donné, dont les jeux de données résultant sont larges et complexes en requierant une analyse qui croise les dimensions spatiales, temporelles, thématiques et socio-économiques pour permettre de découvrir les schémas spatio-temporels de la mobilité quotidienne. Dans ce contexte, la visualisation d'informations est une approche appropriée pour soutenir l'analyse des données de mobilité urbaine, puisque les analystes n'ont pas à apprendre des méthodes sophistiquées pour interpréter les visualisations de données qui viennent renforcer leur cognition et permettent la découverte d'aperçus non structurés dans les données.Ainsi, nous proposons un cadre de visualisation pour aider à l'analyse de la mobilité urbaine à travers des indicateurs décrivant des objets d'intérêt complémentaires au sein des données qui permettent d'aborder trois catégories de questions sous-jacentes au phénomène de la mobilité urbaine. Une première question est de savoir comment les habitants d'un territoire se déplacent au quotidien et quels processus d'échanges entre les lieux cela génère, ce qui l'on peut analyser par l'exploration des quantités, des modalités, de la direction et de la variation des flux et des déplacements en fonction des différents aspects socio-économiques des individus et des types d'espaces. Une deuxième question concerne la variation temporelle de la présence de la population sur un territoire, qui permet de comprendre l'utilisation de différents ``sours-espaces'' en tenant compte des caractéristiques socio-économiques des personnes qui s'y rendent et des activités qu'elles y exercent. La troisième question cherche à expliquer le besoin de déplacement des individus à travers l'ordre temporel des déplacements et des activités des individus (aussi nommés ``trajectoires quotidiennes'') dans le contexte spatial du territoire.Nous proposons un cadre visuel à l'aide de la dérivation et l'exploration visuelle d'indicateurs décrivant le territoire, les flux et les déplacements, et les trajectoires quotidiennes, sur de multiples granularités spatio-temporelles et attributs thématiques. Notre interface de visualisation permet de disperser les représentations visuelles sur de multiples tableaux de bords analytiques, permettant aux utilisateurs de personnaliser l'agencement spatial des visualisations et les indicateurs de manière significative en fonction de l'analyse en cours. De plus, nous proposons une interaction basée sur le mouvement, qui repose sur l'inclinaison d'une tablette et qui permet d'explorer la variation temporelle des indicateurs en tirant parti d'une entrée tactile et tangible. La conception de notre approche de visualisation a suivi un processus d'évaluation interactif qui comprend des évaluations successives auprès des utilisateurs visant à affiner un prototype afin d'atteindre la performance et la satisfaction de l'utilisateurThe research field of urban mobility aims at the observation and design of human trips within an urban environment, which information supports decision-making and problem solving within public policies. In this context, there are many experts -- not necessarily transportation specialists -- that need to handle more or less standardized urban data to extract synthetic and easily exploitable knowledge. Hence, public transportation agencies commonly conduct trip-based surveys to collect information about day-to-day travel of the population within a particular territory (i.e. where and when we travel), resulting in large and complex datasets which analysis requires crossing spatial, temporal, thematic and socioeconomic dimensions to enable discoveries of daily urban mobility patterns. This way, information visualization is a suitable approach to support the analysis of urban mobility data, since analysts do not have to learn sophisticated methods to interpret the data visualizations that come to reinforce their cognition and enable the discovery of unstructured insights within the data.Thereby, we propose a visualization framework to assist the analysis of urban mobility through indicators describing complementary objects of interest within the data that allow to address three categories of questions underlying the urban mobility phenomenon. A first question seeks to understand the daily traveling routine of a population and the resulting processes of exchange between places, which can be studied through the exploration of amounts, modalities, direction, and variation of travel flows and trips according to different socioeconomic aspects of individuals and land types. A second questioning concerns the temporal variation of population presence throughout a territory, which allows to understand the use of distinct locations by taking into account the socioeconomic characteristics of the people visiting it and the activities they carry out there. The third question seeks to explain the individuals' need of traveling by studying the temporal ordering of trips and activities of individuals (i.e. daily trajectories) within the spatial context of the territory.Our framework supports the derivation and visual exploration of indicators describing the territory, travel flows and trips, and daily trajectories, over multiple spatio-temporal resolutions and thematic attributes. Our visualization interface allows to disperse visual representations over multiple analytical displays, enabling users to customize the spatial arrangement of visualizations and indicators in meaningful ways according to the ongoing analysis. Furthermore, we propose a movement-based interaction based on the tilting of a tablet that allows to explore the temporal variation of indicators leveraging tactile and tangible input. The conception of our visualization approach followed an interactive evaluation process that consists of successive user-based evaluations aiming to refine a prototype in order to achieve user performance and satisfaction
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Z'aba, Muhammad Reza. "Analysis of linear relationships in block ciphers." Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/35725/1/Muhammad_Z%27aba_Thesis.pdf.
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This thesis is devoted to the study of linear relationships in symmetric block ciphers. A block cipher is designed so that the ciphertext is produced as a nonlinear function of the plaintext and secret master key. However, linear relationships within the cipher can still exist if the texts and components of the cipher are manipulated in a number of ways, as shown in this thesis. There are four main contributions of this thesis. The first contribution is the extension of the applicability of integral attacks from word-based to bitbased block ciphers. Integral attacks exploit the linear relationship between texts at intermediate stages of encryption. This relationship can be used to recover subkey bits in a key recovery attack. In principle, integral attacks can be applied to bit-based block ciphers. However, specific tools to define the attack on these ciphers are not available. This problem is addressed in this thesis by introducing a refined set of notations to describe the attack. The bit patternbased integral attack is successfully demonstrated on reduced-round variants of the block ciphers Noekeon, Present and Serpent. The second contribution is the discovery of a very small system of equations that describe the LEX-AES stream cipher. LEX-AES is based heavily on the 128-bit-key (16-byte) Advanced Encryption Standard (AES) block cipher. In one instance, the system contains 21 equations and 17 unknown bytes. This is very close to the upper limit for an exhaustive key search, which is 16 bytes. One only needs to acquire 36 bytes of keystream to generate the equations. Therefore, the security of this cipher depends on the difficulty of solving this small system of equations. The third contribution is the proposal of an alternative method to measure diffusion in the linear transformation of Substitution-Permutation-Network (SPN) block ciphers. Currently, the branch number is widely used for this purpose. It is useful for estimating the possible success of differential and linear attacks on a particular SPN cipher. However, the measure does not give information on the number of input bits that are left unchanged by the transformation when producing the output bits. The new measure introduced in this thesis is intended to complement the current branch number technique. The measure is based on fixed points and simple linear relationships between the input and output words of the linear transformation. The measure represents the average fraction of input words to a linear diffusion transformation that are not effectively changed by the transformation. This measure is applied to the block ciphers AES, ARIA, Serpent and Present. It is shown that except for Serpent, the linear transformations used in the block ciphers examined do not behave as expected for a random linear transformation. The fourth contribution is the identification of linear paths in the nonlinear round function of the SMS4 block cipher. The SMS4 block cipher is used as a standard in the Chinese Wireless LAN Wired Authentication and Privacy Infrastructure (WAPI) and hence, the round function should exhibit a high level of nonlinearity. However, the findings in this thesis on the existence of linear relationships show that this is not the case. It is shown that in some exceptional cases, the first four rounds of SMS4 are effectively linear. In these cases, the effective number of rounds for SMS4 is reduced by four, from 32 to 28. The findings raise questions about the security provided by SMS4, and might provide clues on the existence of a flaw in the design of the cipher.
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Hines, Linda Kay 1942. "An Analysis of Enrollment Patterns in Required General Education Courses and the Related Success, as Measured by Grade Point Average, of Technical-Occupational Students in a Multi-Campus Urban Community College." Thesis, University of North Texas, 1988. https://digital.library.unt.edu/ark:/67531/metadc331326/.
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This study investigated the following with regard to technical-occupational students in a multi-campus urban community college: The enrollment patterns in required general education courses at specific intervals of course work; the relation between successful completion of certain required general education courses (English and mathematics) and academic success as measured by grade point average; and the profiles or basic characteristics (age, GPA, sex, and high school graduation status) of (a) the student who had completed a specified amount of general education course work and (b) the graduate who had attained a higher grade point average in technical course work than in general education course work. The data was obtained from the academic records of 328 current student, selected by established criteria, and 284 graduates of six technical-occupational programs. The six programs were chosen by pairs to represent white-collar, technical-skilled, and blue-collar oriented occupations. Data on enrollment patterns were analyzed according to percentage in frequency distributions. Differences in mean grade point averages for completers and non-completers of English and mathematics were analyzed using the t-test. Significant variance among the groups representing types of occupations was analyzed using the chi-square test for independence. The Pearson Product Moment test was used to investigate correlations between grade point average and amount of general education work completed. Among the major findings were the following: over 57 per cent of the current students had completed general education requirements at a level proportional to their total program enrollments; current students tended to avoid enrollment in English more than in mathematics; current students who had completed mathematics had a higher mean GPA than those who had not completed mathematics; graduates who completed mathematics during the first half of the program had a higher mean GPA than those who completed mathematics later; a negative correlation was detected between GPA and the amount of general education course work completed; and more than 81 per cent of the graduates had a higher GPA in technical course work than in general education course work.
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Call, Lara J. "Analysis of intraspecific and interspecific interactions between the invasive exotic tree-of-heaven (Ailanthus altissima (Miller) Swingle) and the native black locust (Robinia pseudoacacia L.)." Thesis, Connect to this title online, 2002. http://scholar.lib.vt.edu/theses/available/etd-05162002-132819/.
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Filho, NarcÃlio de SÃ Pereira. "AnÃlise da dinÃmica espaÃo-temporal (1973 a 2014) das dunas de Jericoacoara, CearÃ, Brasil." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=15910.
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CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel SuperiorDunas costeiras exercem um importante papel na manutenÃÃo do fluxo de sedimentos da zona costeira. O Parque Nacional de Jericoacoara, localizado no estado do CearÃ, regiÃo Nordeste do Brasil, possui uma morfologia pouco frequente, trata-se de um promontÃrio associado com um campo de dunas mÃveis denominadas barcanas, dunas individuais, de grande porte com formato de ferraduras que se deslocam em direÃÃo L â O. Elas realizam o by-pass, o transporte de sedimentos, essencial para a manutenÃÃo da linha de costa. Neste trabalho, foi priorizada a definiÃÃo da evoluÃÃo morfodinÃmica de dunas mÃveis isoladas (dunas Papai Noel, PÃr-do-Sol e Arraia), tendo como referencial teÃrico a anÃlise das paisagens e como procdimento tÃcnico principal a anÃlise espaÃo-temporal do recobrimento de imagens multitemporais dos satÃlites Landsat e Quickbird entre os anos de 1973 a 2014. AtravÃs da comparaÃÃo da distribuiÃÃo espaÃo temporal das morfologias dunares, nesse perÃodo de 41 anos, evidenciaram-se mudanÃas significativas na Ãrea, perÃmetro e deslocamento das dunas. Foi possÃvel constatar a aÃÃo dos fluxos de matÃria e energia vinculados com migraÃÃo continuada direcionada para a faixa de praia (setor de bypassing de sedimentos). A dinÃmica de migraÃÃo das dunas, quando analisadas apÃs as imagens de 2000, evidenciou possibilidades de alteraÃÃes dos aspectos morfolÃgicos influenciados pelo incremento do fluxo turÃstico, quando instituÃdo o PARNA de Jericoacoara. As mudanÃas foram mais significativas, sobretudo, entre os anos de 2001 a 2005, o que pode estar relacionado a uma maior intervenÃÃo humana (fluxo de turistas). A utilizaÃÃo das tÃcnicas de geoprocessamento para o mapeamento da evoluÃÃo morfodinÃmica do campo de dunas do Parque Nacional de Jericoacoara constituiu- se uma ferramenta essencial para a produÃÃo de informaÃÃes que certamente subsidiarÃo a continuidade do planejamento ambiental da referida, que se constitui como uma Unidade de ConservaÃÃo de ProteÃÃo Integral.
Coastal dunes play an important role in the sediment flow of the coastal zone. The unique morphology of the Jericoacoara National Park in the northeastern Brazilian state of Cearà consists of a promontory covered by a mobile dune field consisting of large, horseshoe-shaped dunes known locally as barcanas that migrate from east to west. These dunes are responsible for the by-pass, the transport of sediments essential for the maintenance of the coastline. The present study focused on the morphodynamic evolution of these isolated mobile dunes through the recovery of multitemporal Landsat and Quickbird satellite images from the years between 1975 and 2014. The comparison of the spatio-temporal distribution of the morphology of these dunes over this 41-year period revealed significant shifts in their area, perimeter, and movement. It was possible to confirm that the flow of material and energy were linked to a process of continuous migration in the direction of the beach (sediment bypassing sector). The dynamics of the dune migration in the years following 2000, when the national park was established, indicate possible impacts of the increase in tourism within the area on the morphology of the dunes. The changes were most significant between 2001 and 2005, possibly reflecting a greater influx of tourists and thus more intense anthropogenic impacts. The different geoprocessing techniques applied to the mapping of the morphodynamic evolution of the dune field of the Jericoacoara National Park proved to be an essential tool for the production of information that will guarantee the long-term environmental planning of this integral conservation unit.
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Cyganski, Rita. "Was zieht uns an? Empirische Grundlagen für eine verbesserte Abbildung der Einkaufszielwahl in Verkehrsnachfragemodellen." Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/22101.
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Eine große Herausforderung für Verkehrsmodelle stellt die korrekte Abbildung der Entscheidungsmuster bei der Zielwahl dar. Diese bestimmt die räumlichen Strukturen der Nachfrage und steht in engem Zusammenhang mit zentralen Ergebnissen der Nachfragemodellierung.
Rund ein Drittel der Alltagswege in Deutschland sind Einkaufs- und Erledigungwege. Zahlreiche Arbeiten zeigen die Bedeutung von habitualisierten Verhaltensmustern bei der Wahl eines Einkaufsortes. Die Motive der Geschäftswahl gelten als sehr vielfältig. Besondere Bedeutung wird zudem den Primäraktivitätenorten zugeschrieben. Gleichwohl erfolgt die Abbildung der Zielwahl in der Nachfragemodellierung zumeist sehr vereinfachend. Gewöhnlich wird von einem Versorgungseinkauf mit der Geschäftsgröße und der Anreisezeit ausgegangen.
Diese Arbeit zeigt anhand empirischer Auswertungen Möglichkeiten einer verhaltensorientierten Abbildung der Einkaufszielwahl in mikroskopischen Personenverkehrsmodellen auf. Im Fokus stehen die Variabilität der Geschäftswahl, die ausschlaggebenden Motive sowie die räumlichen Bezugspunkte der Suche. Am Beispiel des Erwerbs von Nahrungs- und Genussmitteln, von Textilien sowie von Unterhaltungselektronik werden Unterschiede zwischen Einkaufswaren verschiedener Fristigkeit, aber auch zwischen verschiedenen Personengruppen herausgearbeitet.
Simulationsrechnungen mit dem Nachfragemodell TAPAS zeigen, dass eine Differenzierung der Einkaufsart sowie die Nutzung eines motivgestützen Erreichbarkeitsmaßes die Modellierungsergebnisse stark verbessern. Die Arbeit stellt erweiterte Indikatoren für eine Berücksichtigung der räumlichen Bezugspunkte bei der Beurteilung der Modellierungsergebnisse bereit. Auch stehen mit den Analysen der Aktivitätenräume, der Umwegfaktoren, der Lage der Einkaufsorte sowie der kumulierten Reiseweiten Informationen zur Verfügung, die generell für die Definition adäquater Suchräume und Bezugspunkte für die Modellierung städtischer Untersuchungsgebiete genutzt werden können.A major challenge in travel demand modelling is the correct representation of decision patterns underlying the choice of destinations. This choice determines the spatial structures of demand and is closely related to central modelling results. Around one third of everyday trips in Germany are for shopping and errands. Numerous studies show the importance of habitualised behavioral patterns when choosing a shopping location. The motives for choosing a shop are considered to be very diverse. Particular importance is attributed to primary activity locations. Nevertheless, the representation of the target choice in demand modelling is usually very simplified. Usually, a supply purchase is implicitly assumed, with the size of the shop and travel time from the previous location being the most important choice criteria. Using empirical analyses, this dissertation shows possibilities for a behavior-oriented depiction of shopping location choice in microscopic passenger transport models. These are discussed in terms of their usability for modeling. The analyses focus on the variability of destinations, the decisive motives and the spatial reference points of the location search. Using the example of the purchase of food and beverages, textiles and consumer electronics, differences between shopping goods of different periodicity and also different groups of people are presented. Simulation calculations with the demand model TAPAS show that a differentiation of the type of purchase and the use of a motive-based accessibility measure greatly improves the modelling results. The dissertation provides extended indicators for a consideration of spatial reference points in the evaluation of the modelling results. Furthermore, the analyses of activity areas, diversion factors, the location of shopping locations and cumulative travel distances provide information that can be generally used to define adequate search areas and reference points for the modelling of urban study areas.Einkaufsverhalten
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Almansa, Andrés. "Echantillonnage, interpolation et détection : applications en imagerie satellitaire." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2002. http://tel.archives-ouvertes.fr/tel-00665725.
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Cette thèse aborde quelques-uns des problèmes qui surviennent dans la conception d'un système complet de vision par ordinateur : de l'échantillonnage à la détection de structures et leur interprétation. La motivation principale pour traiter ces problèmes a été fournie par le CNES et la conception des satellites d'observation terrestre, ainsi que par les applications de photogrammétrie et vidéo-surveillance chez Cognitech, Inc. pendant les étapes finales de ce travail, mais les techniques développées sont d'une généralité suffisante pour présenter un intérêt dans d'autres systèmes de vision par ordinateur. Dans une première partie nous abordons une étude comparative des différents systèmes d'échantillonnage d'images sur un réseau régulier, soit carré soit hexagonal, à l'aide d'une mesure de résolution effective, qui permet de déterminer la quantité d'information utile fournie par chaque pixel du réseau, une fois que l'on a séparé les effets du bruit et du repliement spectral. Cette mesure de résolution est utilisée à son tour pour améliorer des techniques de zoom et de restauration basées sur la minimisation de la variation totale. Ensuite l'étude comparative est poursuivie en analysant dans quelle mesure chacun des systèmes permet d'éliminer les perturbations du réseau d'échantillonnage dues aux micro-vibrations du satellite pendant l'acquisition. Après une présentation des limites théoriques du problème, nous comparons les performances des méthodes de reconstruction existantes avec un nouvel algorithme, mieux adapté aux conditions d'échantillonnage du CNES. Dans une deuxième partie nous nous intéressons à l'interpolation de modèles d'élévation de terrain, dans deux cas particuliers: l'interpolation de lignes de niveau, et l'étude des zones dans lesquelles une méthode de corrélation à partir de paires stéréo ne fournit pas des informations fiables. Nous étudions les liens entre les méthodes classiques utilisées en sciences de la terre tels que Krigeage ou distances géodésiques, et la méthode AMLE, et nous proposons une extension de la théorie axiomatique de l'interpolation qui conduit à cette dernière. Enfin une évaluation expérimentale permet de conclure qu'une nouvelle combinaison du Krigeage avec l'AMLE fournit les meilleures interpolations pour les modèles de terrain. Enfin nous nous intéressons à la détection d'alignements et de leurs points de fuite dans une image, car ils peuvent être utilisés aussi bien pour la construction de modèles d'élévation urbains, que pour résoudre des problèmes de photogrammétrie et calibration de caméras. Notre approche est basée sur la théorie de la Gestalt, et son implémentation effective récemment proposée par Desolneux-Moisan-Morel à l'aide du principe de Helmholtz. Le résultat est un détecteur de points de fuite sans paramètres, qui n'utilise aucune information a priori sur l'image ou la caméra.
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Leininger, Thomas Jeffrey. "Bayesian Analysis of Spatial Point Patterns." Diss., 2014. http://hdl.handle.net/10161/8730.
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We explore the posterior inference available for Bayesian spatial point process models. In the literature, discussion of such models is usually focused on model fitting and rejecting complete spatial randomness, with model diagnostics and posterior inference often left as an afterthought. Posterior predictive point patterns are shown to be useful in performing model diagnostics and model selection, as well as providing a wide array of posterior model summaries. We prescribe Bayesian residuals and methods for cross-validation and model selection for Poisson processes, log-Gaussian Cox processes, Gibbs processes, and cluster processes. These novel approaches are demonstrated using existing datasets and simulation studies.
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Yun, Wang Jeng, and 王政雲. "Regularized Spatial Point Pattern Analysis with Application to Crime Data." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/65687008045495243984.
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碩士國立清華大學
統計學研究所
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This thesis considered an inhomogeneous Poisson process to characterize the spatial point patterns for the crime events in San Francisco area. The data consist of 39 crimes in Year 2008. We study the global spatial patterns of intensity among different crimes and explore possible associations between them. For modeling the intensity functions for all types of crime simultaneously, we use the thin-plate splines to describe the overall intensity baseline function to account for the global and common spatial patterns among crimes. Beyond the global pattern, an extra regression form in terms of the standardized local crime scores are added to the intensity model to capture the specific effects from other crimes. For inference, two types of maximum likelihood estimation (MLE) are implemented: one is based on the detail point data information and the other is based on a coarser block (quadrant) data. Regularization techniques are further incorporated into the likelihood function to smooth the global intensity patterns and to select important association relationship among crimes. Empirical analysis shows a high intensity global patterns centered around the downtown area in San Francisco. It is also found that regularized MLE based on the point data has a higher estimation precision and tends to select a more parsimonious model.
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Amin, Mohammad Ruhul. "Spatial analysis of suicide attack incidences in Kabul City." Master's thesis, 2011. http://hdl.handle.net/10362/8278.
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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.In the last two decades, suicide bombings became quite common among some communities in Iraq, Afghanistan, Pakistan, India, USA, and a few African and European countries. The modeling of reported suicide bombings has been the subject of a few studies, but the pattern of incidents turned out to be difficult to assess. Nevertheless, to uncover the bombing patterns in past incident locations is of major importance because it can improve social security and save human lives. The Capital city of Afghanistan, Kabul, has experienced on average around one suicide attack in every month since 2001. The overall objective of this study is to characterize the spatial and temporal patterns of suicide attacks in Kabul City. This research primarily used last 5 years descriptive spatial information on suicide attacks in Kabul that brought to public by some local and international news paper to generate geographic point data. Suicide attack location points and potential target group establishment point’s data analyzed separately to explore inherent spatial point pattern in terms of intensity and interaction. Finally it analyzed spatial tendency between suicide attack location points on target group establishment locations. It has been explored that both suicide attack locations that occurred from year 2006 to 2010 within the urban habitat of Kabul and target group’s establishment locations are characterized by inhomogeneous intensity and clustered interaction pattern at 98% level of significance. Moreover, there is a tendency of choosing location for suicide attacks close to target group’s establishment location. Finally some interesting temporal characteristics of suicide attack incidences also presented in this study.
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Hesselbarth, Maximilian H. K. "Analysing and modelling spatial patterns to infer the influence of environmental heterogeneity using point pattern analysis, individual-based simulation modelling and landscape metrics." Doctoral thesis, 2020. http://hdl.handle.net/21.11130/00-1735-0000-0005-1391-1.
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Neba, Funwi-Gabga. "Spatial point pattern analysis of gorilla nest sites in the Kagwene Sanctuary, Cameroon: Towards understanding the nesting behavior of a critically endangered subspecies." Master's thesis, 2011. http://hdl.handle.net/10362/8295.
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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.Gorilla nest site data from the Kagwene sanctuary, Cameroon were analyzed to foster an understanding of the nesting behavior of Cross River Gorillas. The main objective of the study was to verify the pattern of nest site distribution in the sanctuary, the influence of environmental covariates and possible interaction between nest sites and between nest sites of two gorilla groups – the Major and Minor groups. Spatial point pattern analysis methods were implemented in the R software environment for this purpose. Overall, we sought to fit models that could best estimate an intensity function for nest site distribution in the sanctuary. Resulting models revealed that nest site distribution does not conform to a Poisson process, and that the data can be better described by a combination of environmental factors and interaction between nest sites. Univariate models fitted to different nest site categories proved to be more useful than bivariate models in defining intensity functions for nest site distribution. The final model category chosen for the data therefore constituted a combination of the effect of covariates and higher-order interaction between nest sites. This set of models, chosen through their AIC values, showed that nest site distribution in the sanctuary exhibits characteristics of attraction so that clustered patterns are observed. Gorillas tend to create hotspots for nest site location, with southern parts of the sanctuary proving to be very much avoided. Intensity tends to increase with increasing distance to the centre of the sanctuary. Coefficients obtained from the models also showed that gorillas prefer constructing nests close to transition vegetation, on steep slopes and generally on east-facing slopes. In the dry season however, colonizing forests exert a greater attraction on nest sites, which can be attributed to the fact that transition zones experience such edge effects as bushfires, and plants that provide food (such as Zingiberaceae) do not bear fruit in this season. These can be assumed to be specific habitat requirements of this subspecies of gorillas. Also, intensity drops with increasing elevation. Interaction parameters obtained from the bivariate models also suggested that there is attraction between nest sites of the Major (sites with more than 6 nests) and the Minor groups. This analysis is the first of its kind for this subspecies, and we recommend that further models can be fitted to include a wider range of covariates (both anthropogenic and natural) as they may be available to expand the scope of the models.
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Pierce, Carl J. "Electromagnetic Induction for Improved Target Location and Segregation Using Spatial Point Pattern Analysis with Applications to Historic Battlegrounds and UXO Remediation." 2010. http://hdl.handle.net/1969.1/ETD-TAMU-2010-08-8331.
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Remediation of unexploded ordnance (UXO) and prioritization of excavation procedures for archaeological artifacts using electromagnetic (EM) induction are studied in this dissertation. Lowering of the false alarm rates that require excavation and artifact excavation prioritization can reduce the costs associated with unnecessary procedures.
Data were taken over 5 areas at the San Jacinto Battleground near Houston, Texas, using an EM-63 metal detection instrument. The areas were selected using the archaeological concepts of cultural and natural formation processes applied to what is thought to be areas that were involved in the 1836 Battle of San Jacinto.
Innovative use of a Statistical Point Pattern Analysis (PPA) is employed to identify clustering of EM anomalies. The K-function uses point {x,y} data to look for possible clusters in relation to other points in the data set. The clusters once identified using K-function will be further examined for classification and prioritization using the Weighted K-function. The Weighted K-function uses a third variable such as millivolt values or time decay to aid in segregation and prioritization of anomalies present.
Once the anomalies of interest are identified, their locations are determined using the Gi-Statistics Technique. The Gi*-Statistic uses the individual Cartesian{x, y} points as origin locations to establish a range of distances to other cluster points in the data set. The segregation and location of anomalies supplied by this analysis will have several benefits. Prioritization of excavations will narrow down what areas should be excavated first. Anomalies of interest can be located to guide excavation procedures within the areas surveyed.
Knowing what anomalies are of greater importance than others will help to lower false alarm rates for UXO remediation or for archaeological artifact selection. Knowing significant anomaly location will reduce the number of excavations which will subsequently save time and money. The procedures and analyses presented here are an interdisciplinary compilation of geophysics, archaeology and statistical analysis brought together for the first time to examine problems associated with UXO remediation as well as archaeological artifact selection at historic battlegrounds using electromagnetic data.
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van, Waveren Clara-Sophie. "The role of heterogeneity in spatial plant population dynamics." Doctoral thesis, 2016. http://hdl.handle.net/11858/00-1735-0000-0023-3F41-6.
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