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1
Emidio, Fernando. "Analysis of multidimensional radiating structures by the spatial Fourier transform and computational electromagnetics." Thesis, Saint-Etienne, 2013. http://www.theses.fr/2013STET4011.
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Ce manuscrit présente les travaux de recherche qui concernent l'analyse et la synthèse de structures rayonnantes multidimensionnelles en utilisant une approche qui combine méthode des moments et la transformée de Fourier spatiale. La distribution source (courant électrique) et le diagramme de rayonnement sont liées par la transformée de Fourier spatiale - la théorie de la Relation de Fourier (FR). La distribution des courants est déterminée en utilisant une méthode d'analyse en électromagnétisme (EM), à savoir la Méthode des Moments (MoM). Des travaux antérieurs utilisant la théorie FR ont été réalisés par d'autres auteurs sur des réseaux linéaires - uniformément espacés ou non uniformes. Les sources radiantes élémentaires des dipoles électriques filaires. Les travaux actuels se développent en utilisant la théorie FR à deux et trois dimensions sur des structures réelles. En utilisant la méthode MoM nous pouvons prendre en compte le rayon du fil, sur n'importe quel point d'excitation (générateur de tension ou onde incidente) et le couplage mutuel entre les éléments, créant ainsi un modèle électromagnétique réaliste pour la structure d'antenneThis manuscript presents the research work in the analysis and synthesis of multidimensional radiating structures using an approach that combines Method of Moments and Spatial Fourier Transform. The source distribution (electric current) and radiation pattern are related by the spatial Fourier Transform - Fourier Relation theory (FR). Current distribution is determined using Computational Electromagnetics (CEM), namely Method of Moments (MoM). Previous work using FR theory was done by other authors on linear arrays – uniformly or nonuniformly spaced elemental radiators laid on a straight line. Present work expands FR theory to two and three dimensions on real-world structures. By using MoM we can take into account wire radius, excitation on any point (voltage generator or incident wave) and mutual coupling between elements, thus creating a realistic electromagnetic model for the antenna structure
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Yeh, Tian-Chyi J., Ming Ye, and Raziuddin Khaleel. "Estimation of effective unsaturated hydraulic conductivity tensor using spatial moments of observed moisture plume." Department of Hydrology and Water Resources, University of Arizona (Tucson, AZ), 2004. http://hdl.handle.net/10150/615768.
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Knowledge of unsaturated zone hydraulic properties is critical for many environmental
and engineering applications. Various stochastic methods have been developed during the past
two decades to estimate the effective unsaturated hydraulic properties. Independent of these
stochastic methods, we develop in this paper a practical approach to estimate the three-dimensional (3 -D) effective unsaturated hydraulic conductivity tensor using spatial moments of
3-D snapshots of a moisture plume under transient flow conditions.
approach
hydraulic
hydraulic
Application of the new
to a field site in southeastern Washington State yields an effective unsaturated
conductivity tensor that exhibits moisture- dependent anisotropy. The effective
conductivities compare well with laboratory- measured unsaturated hydraulic
conductivity data from small core samples; they also reproduce the general behavior of the
observed moisture plume at the site. We also define a moisture diffusivity length concept which
we use in conjunction with estimated correlation scales of the geological media at the field site to
explain deviations between the observed and simulated plumes based on the derived effective
hydraulic properties.
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Tao, Ji. "Spatial econometrics models, methods and applications /." Connect to this title online, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1118957992.
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Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains x, 140 p. Includes bibliographical references (p. 137-140). Available online via OhioLINK's ETD Center
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Wolff, Wagner. "Avaliação e nova proposta de regionalização hidrológica para o Estado de São Paulo." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/11/11152/tde-08042013-102503/.
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A regionalização hidrológica é uma técnica que permite transferir informação entre bacias hidrográficas semelhantes, a fim de calcular em sítios que não dispõem de dados, as variáveis hidrológicas de interesse; assim, a mesma caracteriza-se por ser uma ferramenta útil na obtenção de outorga de direitos de uso de recursos hídricos, instrumento previsto na Lei 9433/97. Devido à desatualização do modelo atual de regionalização hidrológica do Estado de São Paulo, proposto na década de 80, este estudo tem como objetivo geral avaliar se o mesmo está adequado ao uso, de acordo com a atualização de seu banco de dados, e propor um novo que supere as limitações do antigo. O estudo foi realizado no Estado de São Paulo, que tem área de aproximadamente 248197 km², localizado entre as longitudes -44° 9\', e -53º 5\', e entre as latitudes -22° 40\', e -22° 39\'. Utilizou-se, inicialmente, dados de 176 estações fluviométricas administradas pelo DAEE e pela ANA, disponíveis em http://www.sigrh.sp.gov.br. Determinou-se para as estações, a precipitação média anual da bacia hidrográfica (P), a vazão média plurianual (Q), a vazão mínima média de 7 dias seguidos com período de retorno de 10 anos (Q7,10) e as vazões com 90 e 95% de permanência no tempo (Q90 e Q95). Posteriormente, fez-se análise de consistência excluindo as estações inconsistentes do estudo; assim, restaram 172 para serem utilizadas na avaliação do modelo e formulação de um novo. A avaliação do modelo fez-se pelo índice de confiança (c), que é definido pelo produto entre o coeficiente de correlação (r) e o índice de concordância (d), utilizando como valor de estimativa as vazões geradas pelo modelo, e como valor padrão as calculadas por intermédio das estações fluviométricas. Todas as vazões avaliadas foram classificadas como ótimas, com índice de confiança (c) acima de 0,85; assim, o atual modelo rejeitou a hipótese de que a atualização de seu banco de dados pudesse inferir em sua capacidade preditiva; portanto, o mesmo pode ser usado na obtenção das vazões estudadas que são referência na emissão de outorga em diferentes Estados do Brasil. Entretanto, o modelo apresentou algumas limitações, como extrapolação para áreas de bacias de drenagem menores do que as utilizadas para formulá-lo, e problemas em seu aplicativo computacional: o mesmo informa a precipitação média anual na coordenada geográfica do local de captação da água, e não da bacia de drenagem a montante do referido local. Neste enfoque, foi formulado um novo modelo, que superou as limitações e proporcionou capacidade preditiva maior que a do antigo.A hydrological regionalization is a technique that allows to transfer information between similar watersheds in order to calculate, in sites where there are no data on the hydrological variables of interest. This technique becomes a useful tool to ensure the rights of water resources use, instrument provided by Law 9433/97. Due to the outdated hydrological regionalization model of São Paulo State, proposed in the 1980\'s, this study aims to broadly assess whether the current model is appropriate to use, according to an analysis of its update database and to propose a new model to overcome the limitations of the current one. The study was conducted in State São Paulo with area of approximately 248197 km ², located between longitudes -44 ° 9 \', and -53 ° 5\', and between latitudes 40 ° -22\' and -22 ° 39\'. We used data from 176 initially gauged stations administered by ANA and DAEE available at http://www.sigrh.sp.gov.br, where it was determined to the stations, the average annual rainfall of the basin (P) multiannual average streamflow (Q), streamflow minimum average of 7 consecutive days with a return period of 10 years (Q7,10) and streamflows with 90 and 95% of permanence in time(Q90 e Q95). Afterwards, we analyzed the consistency excluding the inconsistent stations from the study, thus, remaining 172 to be used in the model evaluation and development of a new model. The model evaluation was made by the confidence index (c), which is the product between the correlation coefficient (r) and the agreement index (d), using as estimate value the streamflows generated by the model and as the standard value, the streamflows calculated through the gauged stations. All streamflows evaluated were classified as optimal, with confidence index (c) above 0.85, therefore, the current model rejected the hypothesis that upgrading the database could infer its predictive ability, so, it can be used to obtain the streamflows studied that refer to use grants in different States of Brazil. However, the model had some limitations, such as extrapolation to areas of smaller watersheds than those used to formulate it, and computer application problems, being that, it reports the average annual precipitation at the geographic coordinate at the local catchment water, not the watershed upstream of that location. A new model was formulated that surpasses the limitations and provides greater predictive ability than the current one.
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Badinger, Harald, and Peter Egger. "Fixed Effects and Random Effects Estimation of Higher-Order Spatial Autoregressive Models with Spatial Autoregressive and Heteroskedastic Disturbances." WU Vienna University of Economics and Business, 2014. http://epub.wu.ac.at/4126/1/wp173.pdf.
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This paper develops a unified framework for fixed and random effects estimation of higher-order spatial autoregressive panel data models with spatial autoregressive
disturbances and heteroskedasticity of unknown form in the idiosyncratic error component. We derive the moment conditions and optimal weighting matrix without distributional assumptions for a generalized moments (GM) estimation procedure of the spatial autoregressive parameters of the disturbance process and define both a random effects and a fixed effects spatial generalized two-stage least squares estimator for the regression parameters of the model. We prove consistency of the proposed estimators and derive their joint asymptotic distribution, which is robust to heteroskedasticity of unknown form in the idiosyncratic error component. Finally, we derive a robust Hausman-test of the spatial random against the spatial fixed effects model. (authors' abstract)Series: Department of Economics Working Paper Series
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Yanni, Mamdouh. "The influence of thresholding and spatial resolution variations on the performance of the complex moments descriptor feature extractor." Thesis, University of Kent, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262371.
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Othmani, Wadie. "Pratiques et moments touristiques des Tunisiens et des Maghrébins dans la métropole de Tunis." Thesis, Angers, 2018. http://www.theses.fr/2018ANGE0032/document.
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Le tourisme contribue à hauteur de plus de 15 % dans le PIB national tunisien (WTTC, 2017 : p 1). Ce secteur, depuis sa création dans le milieu des années soixante-dix, a toujours été un des plus importants moteurs de l’économie du pays. Depuis le début des années deux mille, le modèle, basé sur la commercialisation des produits classiques [4 S : sea, sun, sand (plage), sand (désert)] à une clientèle majoritairement occidentale, a atteint la saturation. Au cours de cette période, la chute a commencé à se sentir jusqu’à atteindre une situation critique aggravée par les événements terroristes qu’a subi le pays en 2015. Pour faire face à cette situation, les acteurs du secteur sont allés épuiser dans leur réserve stratégique qui n’était rien d’autre que le touriste national et le touriste maghrébin, essentiellement les Algériens et les Libyens : voisins immédiats de la Tunisie. Actuellement, ces touristes représentent les nationalités les plus présentes en Tunisie post-révolution.Cette thèse de doctorat a examiné le sujet via le recours à des analyses des documents statistiques officiels, des entretiens auprès des différents acteurs qui agissent sur le secteur touristique tunisien, des observations ciblant plusieurs hauts lieux touristiques dans la métropole Tunis et une enquête statistique. La population touristique ciblée est riche et variée puisqu’elle concerne les tunisiens (touristes nationaux), les Algériens, les Libyens, les Marocains, les mauritaniens et la diaspora maghrébine qui émane essentiellement des pays en dehors du territoire du Grand Maghreb, majoritairement de l’Occident. De ce fait, nous avons commencé par réfuter la thèse adoptée par des chercheurs occidentaux prétendant que l’accès au tourisme pour les sociétés en voie de développement est un phénomène récent. Par la suite, nous avons présenté comment ces touristes maghrébins consomment l’espace du Grand Tunis et dans quels lieux ils se concentrent. La thèse a permis également de dresser des profils des touristes maghrébins. Ce profilage se base sur l’âge, le sexe, la catégorie socioprofessionnelle et sur le pays de provenance du touriste. Dans d’autres termes, cette analyse répond aux besoins d’une population touristique nationale et maghrébine actuelle, mais aussi elle se considère comme une étude stratégique pour la population touristique du futur : les jeunes qui seront adultes et les adultes qui seront plus âgésTourism contributes more than 15% of Tunisia's national GDP (WTTC, 2017: p 1). This sector, since its creation in the mid-seventies, has always been one of the most important engines of the country's economy. Since the beginning of the two thousand years, the model, based on the marketing of classic products [4 S: sea, sun, sand (beach), sand (desert)] to a predominantly Western clientele, has reached saturation. During this period, the fall began to feel until reaching a critical situation aggravated by the terrorist events that the country suffered in 2015. To cope with this situation, the actors of the sector went to exhaust in their strategic reserve that was nothing but the national tourist and the Maghreb tourist, mainly Algerians and Libyans: immediate neighbors of Tunisia. Currently, these tourists represent the nationalities most present in post-revolution Tunisia. This doctoral thesis examined the subject through the use of analyzes of official statistical documents, interviews with the various actors who act on the Tunisian tourism sector, observations targeting several major tourist sites in the Tunis metropolis and a statistical survey. The targeted tourist population is rich and varied since it concerns Tunisians (national tourists), Algerians, Libyans, Moroccans, Mauritanians and the Maghreb diaspora, which comes mainly from countries outside the territory of the Greater Maghreb, mainly 'West. As a result, we began by refuting the thesis adopted by Western researchers claiming that access to tourism for developing societies is a recent phenomenon. Subsequently, we presented how these Maghreb tourists consume the space of Greater Tunis and in what places they focus. The thesis also made it possible to draw profiles of Maghreb tourists. This profiling is based on the age, gender, socio-professional category and country of origin of the tourist. In other words, this analysis meets the needs of a current national and North African tourist population, but it also considers itself a strategic study for the tourist population of the future: young adults and adults who will be older
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Badinger, Harald, and Peter Egger. "Estimation and Testing of Higher-Order Spatial Autoregressive Panel Data Error Component Models." Springer, 2013. http://epub.wu.ac.at/5468/1/JoGS_2012.pdf.
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This paper develops an estimator for higher-order spatial autoregressive panel data error component models with spatial autoregressive disturbances, SARAR(R,S). We derive the moment conditions and optimal weighting matrix without distributional assumptions for a generalized moments (GM) estimation procedure of the spatial autoregressive parameters of the disturbance process and define a generalized two-stage least squares estimator for the regression parameters of the model. We prove consistency of the proposed estimators, derive their joint asymptotic distribution, and provide Monte Carlo evidence on their small sample performance.
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Xu, Xingbai Xu. "Asymptotic Analysis for Nonlinear Spatial and Network Econometric Models." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461249529.
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Andriamanampisoa, Lala Bakonirina. "Simulation de la diffraction par des réseaux lamellaires 1D par la méthode modale en différences finies et la méthode des moments en coordonnées paramétriques." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2010. http://tel.archives-ouvertes.fr/tel-00653380.
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Ce manuscrit est consacré à l'amélioration des deux méthodes numériques : MMDF et Méthode des Moments avec la technique de la RSA. Dans un premier temps, on présente les outils théoriques sur l'étude du problème de la diffraction par des réseaux lamellaires, éclairée sous incidence classique et les outils de simulation pour résoudre les équations de Maxwell. On choisit comme fonctions de base et de test, les fonctions triangles. On introduit par la suite, la technique de la RSA afin d'améliorer la vitesse de convergence de calcul. Les résultats obtenus sont comparés à ceux de la méthode MMFE et la méthode MMDF de "Lalanne et al". Une étude numérique de la stabilité et de la convergence de la méthode est effectuée. Enfin, on présente une extension de la Méthode des Moments basée sur l'hypothèse de Galerkin au cas de l'incidence conique. Le détail de la résolution des équations Maxwell est décrit. L'application numérique est traitée dans le cas du réseau diélectrique pour mettre au point les influences de l'état de la polarisation et les paramètres physiques.
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Grahl, Paulo Gustavo de Sampaio. "Essays on Spatial Econometrics." reponame:Repositório Institucional do FGV, 2012. http://hdl.handle.net/10438/11268.
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Esta dissertação concentra-se nos processos estocásticos espaciais definidos em um reticulado, os chamados modelos do tipo Cliff & Ord. Minha contribuição nesta tese consiste em utilizar aproximações de Edgeworth e saddlepoint para investigar as propriedades em amostras finitas do teste para detectar a presença de dependência espacial em modelos SAR (autoregressivo espacial), e propor uma nova classe de modelos econométricos espaciais na qual os parâmetros que afetam a estrutura da média são distintos dos parâmetros presentes na estrutura da variância do processo. Isto permite uma interpretação mais clara dos parâmetros do modelo, além de generalizar uma proposta de taxonomia feita por Anselin (2003). Eu proponho um estimador para os parâmetros do modelo e derivo a distribuição assintótica do estimador. O modelo sugerido na dissertação fornece uma interpretação interessante ao modelo SARAR, bastante comum na literatura. A investigação das propriedades em amostras finitas dos testes expande com relação a literatura permitindo que a matriz de vizinhança do processo espacial seja uma função não-linear do parâmetro de dependência espacial. A utilização de aproximações ao invés de simulações (mais comum na literatura), permite uma maneira fácil de comparar as propriedades dos testes com diferentes matrizes de vizinhança e corrigir o tamanho ao comparar a potência dos testes. Eu obtenho teste invariante ótimo que é também localmente uniformemente mais potente (LUMPI). Construo o envelope de potência para o teste LUMPI e mostro que ele é virtualmente UMP, pois a potência do teste está muito próxima ao envelope (considerando as estruturas espaciais definidas na dissertação). Eu sugiro um procedimento prático para construir um teste que tem boa potência em uma gama de situações onde talvez o teste LUMPI não tenha boas propriedades. Eu concluo que a potência do teste aumenta com o tamanho da amostra e com o parâmetro de dependência espacial (o que está de acordo com a literatura). Entretanto, disputo a visão consensual que a potência do teste diminui a medida que a matriz de vizinhança fica mais densa. Isto reflete um erro de medida comum na literatura, pois a distância estatística entre a hipótese nula e a alternativa varia muito com a estrutura da matriz. Fazendo a correção, concluo que a potência do teste aumenta com a distância da alternativa à nula, como esperado.
This dissertation focus on spatial stochastic process on a lattice (Cliff & Ord--type of models). My contribution consists of using Edgeworth and saddlepoint series to investigate small sample size and power properties of tests for detecting spatial dependence in spatial autoregressive (SAR) stochastic processes, and proposing a new class of spatial econometric models where the spatial dependence parameters that enter the mean structure are different from the ones in the covariance structure. This allows a clearer interpretation of models' parameters and generalizes the set of local and global models suggested by Anselin (2003) as an alternative to the traditional Cliff & Ord models. I propose an estimation procedure for the model's parameters and derive the asymptotic distribution of the parameters' estimators. The suggested model provides some insights on the structure of the commonly used mixed regressive, spatial autoregressive model with spatial autoregressive disturbances (SARAR). The study of the small sample properties of tests to detect spatial dependence expands on the existing literature by allowing the neighborhood structure to be a nonlinear function of the spatial dependence parameter. The use of series approximations instead of the often used Monte Carlo simulation allows a simple way to compare test properties across different neighborhood structures and to correct for size when comparing power. I obtain the power envelope for testing the presence of spatial dependence in the SAR process using the optimal invariant test statistic, which is also locally uniformly most powerful invariant (LUMPI). I have found that the LUMPI test is virtually UMP since its power is very close to the power envelope. I suggest a practical procedure to build a test that, while not UMP, retain good power properties in a wider range for the spatial parameter when compared to the LUMPI test. I find that power increases with sample size and with the spatial dependence parameter -- which agrees with the literature. However, I call into question the consensus view that power decreases as the spatial weight matrix becomes more densely connected. This finding in the literature reflects an error of measure because the hypothesis being compared are at very different statistical distance from the null. After adjusting for this, the power is larger for alternative hypothesis further away from the null -- as one would expect.
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Guilbon, Sabrina. "Développement d'un modèle microphysique de nuages pour un modèle de climat global vénusien." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLV006/document.
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Les conditions à la surface de Vénus sont infernales : température de plus de 400 C, pression atmosphérique 90 fois celle sur Terre dans une atmosphère composée à 96 % de dioxyde de carbone. Une particularité de cette planète est la couche opaque nuageuse de 20 km d'épaisseur qui couvre toute la planète. Les nuages ont un rôle crucial pour le transfert de rayonnement, la dynamique atmosphérique, dans le cycle de certaines espèces chimiques comme le soufre et plus généralement pour le climat de Vénus. Malgré de nombreuses missions spatiales consacrées à cet astre depuis 1961, il y a peu de mesures in-situ. Les couches basses des nuages sont diciles à étudier par satellite, par conséquent il existe encore de nombreuses questions au sujet des nuages : leurs propriétés et leurs impacts radiatifs, dynamiques et chimiques sont mal contraints. Composées majoritairement d'acide sulfurique en solution, les particules sont supposées sphériques et liquides et composent des nuages étalés verticalement entre 50 et 70 km d'altitude environ, entourés par des brumes entre 30 et 50 km et au-dessus de 70 km. Les gouttelettes ont été classées, d'après des observations, en trois modes en fonction de leur taille et de leur composition : les modes 1 et 2 respectivement pour les petites (r = 0.2 μm) et moyennes particules (r = 1.0 μm), et un troisième mode qui contiendrait les plus grandes particules (r = 3.5 μm). Ce dernier mode, qui a été détecté par la sonde Pioneer Venus, demeure de composition et d'existence incertaines, et il n'est pas pris en compte dans notre étude. Afin de compléter et de mieux comprendre les données obtenues par l'observation spatiale, un modèle modal de microphysique, nommé MADMuphy (Modal Aerosol Dynamics with Microphysics), a été développé. L'objectif est d'intégrer MAD-Muphy dans le modèle de climat global vénusien (IPSL-VGCM), il faut donc limiter le nombre de variables que le VGCM doit suivre dans le temps et l'espace (également appelé traceurs). La méthode des moments est déjà utilisée dans les GCM de Titan et de Mars et constitue un bon compromis entre la précision des résultats et le temps de calcul. MAD-Muphy est donc basé sur cette représentation pour une pression et une température dé nies pour une couche de l'atmosphère (ou 0D). La thèse présentée ici détaille le développement des expressions mathématiques des équations de la microphysique avec les moments, présente le nouveau modèle MAD-Muphy ainsi que les hypothèses qui ont été nécessaires pour son développement. Tout d'abord, nous déterminerons le temps caractéristique de chaque processus microphysique et nous étudierons leur comportement en 0D. Ensuite, nos résultats seront comparés avec ceux du modèle sectionné SALSA en 0DThe conditions on the surface of Venus are infernal: temperature of more than 400 C, 90 times the Earth's atmospheric pressure in an atmosphere composed of 96 % of carbon dioxide. A distinctive characteristic of this planet is the 20 km thick opaque cloud layer, which enshrouds the planet. Clouds have a crucial role in radiative transfer, atmospheric dynamics, in the cycle of some chemical species like sulphur and more generally in the climate of Venus. Despite the numerous space missions devoted to this object since 1961, there are few in-situ measurements. The lower cloud layers are di cult to study by satellite, so there are still many questions about clouds: their properties and their radiative, dynamic and chemical impacts are poorly constrained. Predominantly composed of sulphuric acid solution, the particles are supposed to be spherical and liquid and compose the clouds that are vertically spread between approximately 50 and 70 km of altitude, surrounded by hazes between approximately 30 and 50 km and above 70 km. Based on observations the droplets have been classied into three modes according to their size and composition: modes 1 and 2 respectively for small (r = 0.2 μm) and medium particles (r = 1.0 μm), and a third mode that would contain the largest particles (r = 3.5 μm). The latter mode, which has been detected by the Pioneer Venus probe, remains uncertain in composition and existence, and is not taken into account in our study. To complete and better understand the observational data, a modal microphysical model, called MAD-Muphy (Modal Aerosol Dynamics with Microphysics), has been developed. The goal is to integrate MAD-Muphy into the venusian global climate model (IPSL-VGCM), so we must limit the number of variables that the VGCM must follow in time and space (also called tracers). The moment method is already used in the Titan and Mars GCMs and is a good compromise between the accuracy of the results and the computation time. MAD-Muphy is the refore based on this representation for a pressure and a temperature of one atmospheric layer (or 0D). The thesis presented here details the derivation of the mathematical expressions of the microphysical equations with moments, presents the new MAD-Muphy model as well as the hypotheses that were necessary for its development. We will first determine the characteristic timescale of each microphysical process and we will study their behaviour in 0D. Then, our results will be compared with those of the SALSA sectional model in 0D
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Sánchez, Cruz (Sánchez Ruiz). "Vallée du Khabour. Quartiers d'habitation et premiers moments de l'urbanisme en Mésopotamie du Nord." Doctoral thesis, Universitat Pompeu Fabra, 2012. http://hdl.handle.net/10803/80904.
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Este trabajo está dedicado al estudio de la arquitectura doméstica de los yacimientos del valle del Habur (Siria), durante el periodo que va desde el Neolítico hasta el segundo milenio a.C.
Basándonos en la información de los registros arqueológicos de los asentamientos hemos podido observar en la arquitectura de las construcciones domésticas un empleo sistemático del ladrillo “crudo”, así como una gran homogeneidad en la forma, dimensiones y distribución espacial de las casas, durante todo el período estudiado. Nos encontramos con pequeñas construcciones rectangulares en su gran mayoría, con tres o cuatro habitaciones, más una habitación central que sirve para organizar la circulación interior. La entrada a las casas es estrecha, y se encuentran en su interior hornos, hogares, estructuras de almacenaje y bancos adosados a la pared, lo que nos indica una doble utilización del espacio, como vivienda y lugar de trabajo.
El análisis de los datos de que disponemos sugiere una uniformidad arquitectónica en este periodo en el que se sitúa el origen de la sedentarización y el urbanismo.The aim of this thesis is to the study the domestic architecture of the sites located in the Khabur Valley (Syria), during the period between the Neolithic and the second millennium b.C. According to the information found in the archaeological reports of the sites, we can observe a systematic use of the mud brick in the architecture of the domestic constructions, as well as a great homogeneity in the shape, dimensions and spatial distribution of the houses, during the whole period considered. We find mostly small rectangular constructions, with three or four rooms, plus a central room used to organize the internal circulation. The entrance to the houses is narrow, and inside we find ovens, fireplaces and associated structures, which indicates a double use of the interior space, as a house and a work place. The analysis of the data suggests an architectonic uniformity during this period when the origin of the sedentarization and urbanism took place.
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Kiefer, Hua. "Essays on applied spatial econometrics and housing economics." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1180467420.
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Lin, Xu. "Essays on theories and applications of spatial econometric models." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1147892372.
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Couétard, Yves. "CARACTERISATION ET ETALONNAGE DES DYNAMOMETRES A SIX COMPOSANTES POUR TORSEUR ASSOCIE A UN SYSTEME DE FORCES." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2000. http://tel.archives-ouvertes.fr/tel-00285756.
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La mécanique du solide exploite largement le modèle "torseur" pour traiter les systèmes de forces, la cinématique, la cinétique et les petits déplacements. Cette modélisation n'est pas très utilisée en dehors du milieu de la formation initiale, résolument abstraite. Nous nous efforçons de la rendre consistante par une quantification au travers de la mesure, et plus encore au travers de l'élaboration d'un appareil de mesure : un dynamomètre a 6 composantes pour quantifier les composantes du torseur associe au système d'actions mécaniques appliqué sur une liaison. L'étalonnage spatial accompagne l'étude pour permettre de qualifier les appareils de mesure.
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Badinger, Harald, and Peter Egger. "Spacey Parents and Spacey Hosts in FDI." WU Vienna University of Economics and Business, 2013. http://epub.wu.ac.at/3924/2/wp154.pdf.
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Empirical trade economists have found that shocks on foreign direct investment (FDI) of some parent country
in a host country affect the same parent country´s FDI in other hosts (interdependent hosts). Independent of this, there is evidence that shocks on a parent country´s FDI in some host economy affect other parent countries´ FDI in the same host (interdependent parents). In general equilibrium, shocks on FDI between any country pair will affect all country-pairs´ FDI in the world, including anyone of the two countries in a pair as well as third countries (interdependent third countries). No attempt has been made so far to allow simultaneously for all three modes of interdependence of FDI. Using cross-sectional data on FDI among 22 OECD countries in 2000, we employ a spatial feasible generalized two-stage least squares and generalized moments estimation framework to allow for all three modes of interdependence across all parent and host countries, thereby distinguishing between market-size-related and remainder interdependence. Our results highlight the complexity of multinational enterprises´
investment strategies and the interconnectedness of the world investment system (authors' abstract).Series: Department of Economics Working Paper Series
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Hou, Xian. "Detections of seven faint g-ray pulsars and constraints on neutron star moments of inertia with the Fermi-LAT." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-01058049.
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Le Large Area Telescope (LAT) à bord du satellite Fermi, lancé le 11 Juin 2008, est sensible au rayonnement gamma de20 MeV à plus de 300 GeV. 148 pulsars gamma à ce jour ont été détectés avec le Fermi-LAT, dont 117 sont détaillés dansle Deuxième Catalogue de Pulsars gamma de Fermi (2PC). Les pulsars forment la plus grande classe de sources au GeVdans la Voie Lactée. Les études de pulsars gamma apportent des contraintes importantes sur les modèles d'émission gamma etpermettent des percées dans notre compréhension des pulsars.Cette thèse présente des détections de sept pulsars gamma faibles déjà connus en radio, dont quatre jeunes ou d'âgesmoyens et trois millisecondes (MSP). L'analyse spectrale et la caractérisation des courbes de lumiére sont décriteset comparées à la population de 2PC. Ces détections ont l'intérêt particulier de sonder et d'étendre l'espace desparamètres de la population actuelle. Elles illustrent la distorsion inhérente dans 2PC et marquent la transition de lapremière phase (pulsars brillants) à la seconde phase (pulsars faibles) d'opération de Fermi. Le développement desmodèles théoriques et un recensement complet de la population galactique des étoiles à neutrons bénéficieront de plusde détections de pulsars faibles dans les années à venir.Certains pulsars gamma dans 2PC manifestant de grande efficacité gamma sont étudiés dans cette thèse. L'examen desdifférents paramètres qui influencent l'efficacité conduit à quelques candidats pour lesquels un plus grand momentd'inertie est nécessaire afin de résoudre le paradoxe de grande efficacité. Les observations de Fermi en rayons gamma ontl'air à apporter des contraintes indépendantes sur le moment d'inertie et les équations d'état des étoiles à neutrons.
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Ahmed, Mohamed Salem. "Contribution à la statistique spatiale et l'analyse de données fonctionnelles." Thesis, Lille 3, 2017. http://www.theses.fr/2017LIL30047/document.
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Ce mémoire de thèse porte sur la statistique inférentielle des données spatiales et/ou fonctionnelles. En effet, nous nous sommes intéressés à l’estimation de paramètres inconnus de certains modèles à partir d’échantillons obtenus par un processus d’échantillonnage aléatoire ou non (stratifié), composés de variables indépendantes ou spatialement dépendantes.La spécificité des méthodes proposées réside dans le fait qu’elles tiennent compte de la nature de l’échantillon étudié (échantillon stratifié ou composé de données spatiales dépendantes).Tout d’abord, nous étudions des données à valeurs dans un espace de dimension infinie ou dites ”données fonctionnelles”. Dans un premier temps, nous étudions les modèles de choix binaires fonctionnels dans un contexte d’échantillonnage par stratification endogène (échantillonnage Cas-Témoin ou échantillonnage basé sur le choix). La spécificité de cette étude réside sur le fait que la méthode proposée prend en considération le schéma d’échantillonnage. Nous décrivons une fonction de vraisemblance conditionnelle sous l’échantillonnage considérée et une stratégie de réduction de dimension afin d’introduire une estimation du modèle par vraisemblance conditionnelle. Nous étudions les propriétés asymptotiques des estimateurs proposées ainsi que leurs applications à des données simulées et réelles. Nous nous sommes ensuite intéressés à un modèle linéaire fonctionnel spatial auto-régressif. La particularité du modèle réside dans la nature fonctionnelle de la variable explicative et la structure de la dépendance spatiale des variables de l’échantillon considéré. La procédure d’estimation que nous proposons consiste à réduire la dimension infinie de la variable explicative fonctionnelle et à maximiser une quasi-vraisemblance associée au modèle. Nous établissons la consistance, la normalité asymptotique et les performances numériques des estimateurs proposés.Dans la deuxième partie du mémoire, nous abordons des problèmes de régression et prédiction de variables dépendantes à valeurs réelles. Nous commençons par généraliser la méthode de k-plus proches voisins (k-nearest neighbors; k-NN) afin de prédire un processus spatial en des sites non-observés, en présence de co-variables spatiaux. La spécificité du prédicteur proposé est qu’il tient compte d’une hétérogénéité au niveau de la co-variable utilisée. Nous établissons la convergence presque complète avec vitesse du prédicteur et donnons des résultats numériques à l’aide de données simulées et environnementales.Nous généralisons ensuite le modèle probit partiellement linéaire pour données indépendantes à des données spatiales. Nous utilisons un processus spatial linéaire pour modéliser les perturbations du processus considéré, permettant ainsi plus de flexibilité et d’englober plusieurs types de dépendances spatiales. Nous proposons une approche d’estimation semi paramétrique basée sur une vraisemblance pondérée et la méthode des moments généralisées et en étudions les propriétés asymptotiques et performances numériques. Une étude sur la détection des facteurs de risque de cancer VADS (voies aéro-digestives supérieures)dans la région Nord de France à l’aide de modèles spatiaux à choix binaire termine notre contributionThis thesis is about statistical inference for spatial and/or functional data. Indeed, weare interested in estimation of unknown parameters of some models from random or nonrandom(stratified) samples composed of independent or spatially dependent variables.The specificity of the proposed methods lies in the fact that they take into considerationthe considered sample nature (stratified or spatial sample).We begin by studying data valued in a space of infinite dimension or so-called ”functionaldata”. First, we study a functional binary choice model explored in a case-controlor choice-based sample design context. The specificity of this study is that the proposedmethod takes into account the sampling scheme. We describe a conditional likelihoodfunction under the sampling distribution and a reduction of dimension strategy to definea feasible conditional maximum likelihood estimator of the model. Asymptotic propertiesof the proposed estimates as well as their application to simulated and real data are given.Secondly, we explore a functional linear autoregressive spatial model whose particularityis on the functional nature of the explanatory variable and the structure of the spatialdependence. The estimation procedure consists of reducing the infinite dimension of thefunctional variable and maximizing a quasi-likelihood function. We establish the consistencyand asymptotic normality of the estimator. The usefulness of the methodology isillustrated via simulations and an application to some real data.In the second part of the thesis, we address some estimation and prediction problemsof real random spatial variables. We start by generalizing the k-nearest neighbors method,namely k-NN, to predict a spatial process at non-observed locations using some covariates.The specificity of the proposed k-NN predictor lies in the fact that it is flexible and allowsa number of heterogeneity in the covariate. We establish the almost complete convergencewith rates of the spatial predictor whose performance is ensured by an application oversimulated and environmental data. In addition, we generalize the partially linear probitmodel of independent data to the spatial case. We use a linear process for disturbancesallowing various spatial dependencies and propose a semiparametric estimation approachbased on weighted likelihood and generalized method of moments methods. We establishthe consistency and asymptotic distribution of the proposed estimators and investigate thefinite sample performance of the estimators on simulated data. We end by an applicationof spatial binary choice models to identify UADT (Upper aerodigestive tract) cancer riskfactors in the north region of France which displays the highest rates of such cancerincidence and mortality of the country
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Liu, Xiaodong. "Econometrics on interactions-based models methods and applications /." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1180283230.
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Bauch, Christopher Thomas. "Moment closure approximations in epidemiology." Thesis, University of Warwick, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364626.
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Courtois, Nathalie. "Caractérisation de la dispersion en aquifère hétérogène par méthodes de traçages et modélisation stochastique : Application à la nappe alluviale du Drac, à Grenoble." Paris, ENMP, 1999. http://www.theses.fr/1999ENMP0002.
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La dispersion à grande échelle en aquifère est principalement dominée par la structure spatiale du champ des perméabilités. L’objectif est ici de caractériser les propriétés dispersives de l’aquifère alluvial du Drac par deux approches basées sur l’utilisation de données expérimentales de traçage. La première approche est classique : des traçages en écoulement naturel sont menés sur un site expérimental comportant 17 puits crépinés sur toute leur hauteur, et permettant une extension maximale de 45m dans l’axe du gradient. La restitution est suivie dans les puits situés en aval, dont la concentration est homogénéisée sur la hauteur. Les paramètres hydrodispersifs sont obtenus par calage de la solution analytique de l’équation de convection-dispersion en 2D sur les courbes expérimentales. La seconde approche consiste à caractériser la variabilité spatiale du champ des perméabilités, pour générer ensuite des champs stochastiques. La distribution verticale des vitesses de Darcy horizontales est mesurée dans les puits par la méthode de dilution ponctuelle, qui est modélisée comme une combinaison de systèmes d’écoulement simples conduisant à une expression analytique. La vitesse de Darcy est alors déduite par calage du modèle sur les courbes expérimentales de dilution, et la perméabilité en découle en supposant un gradient hydraulique moyen sur la parcelle. Ces profils verticaux, menés sur les 17 forages, conduisent à 185 valeurs de perméabilités, moyennées sur 1 mètre. La distribution des perméabilités est supposée suivre une loi de distribution lognormale. La corrélation spatiale est décrite par les variogrammes calculés dans les directions horizontale et verticale. Deux types de modèles de variogrammes sont alors testés : le modèle classique exponentiel, et un autre plus complexe avec ‘effet de trou’ pour simuler la chenalisation. Des champs de perméabilités stochastiques 3D suivant ces deux lois spatiales sont générés à l’aide du logiciel de géostatistique ISATIS, pour être ensuite incorporés dans le code de calcul aux éléments finis CASTEM2000 qui calcule les champs d’écoulement associés. Le transport est modélisé par suivi de particules et technique de Monte-Carlo. Les paramètres hydrodispersifs se déduisent du calcul des moments spatiaux d’ordres 1 et 2 des nuages de particules. Les dispersivités simulées sont alors comparées aux dispersivités déduites des expériences de traçages, et à celles prédites par les théories stochastiques. La dispersivité longitudinale semble avoir atteint une limite asymptotique au terme d’un parcours moyen de l’ordre de la dizaine de longueurs de corrélation horizontaleDispersion in aquifer at large scale is mainly dominated by the spatial structure of the hydraulic conductivity field. The aim of the study is to characterize the dispersive properties of an alluvial aquifer located near Grenoble through two approaches both based on the use of experimental tracing data. The first approach is the classical one: some field-scale tracer tests are conducted under natural gradient on an experimental site which includes 17 fully-penetrating wells. The maximum extent is about 45 meters along the main flow direction. Fluorescent tracers are injected, and their migration is monitored in the restitution wells by sampling device of the volume-averaged concentration. The hydrodispersive parameters are estimated by fitting the classical 2D analytical solution of the advection-dispersion equation on the experimental breakthrough curves. The second approach is to characterize the spatial variability of hydraulic conductivity, in order to generate stochastic fields. The vertical distribution of the horizontal groundwater flow is measured in boreholes by dilution method. This measurement method is modelled as a combination of simple flow structures, which leads to an analytical expression of the tracer concentration versus time. The flow is estimated from the fit of this analytical model on the experimental dilution curves. Hydraulic conductivity is then deduced from the flow through the Darcy’s equation, supposing an average hydraulic gradient on the site. Such vertical profiles on one-meter averaged hydraulic conductivities are conducted in wells to give 185 values on the entire site. The distribution of hydraulic conductivity draws near to a lognormal one, and is assumed to be so in the later generation of stochastic fields. The spatial correlation of the measured data is described by variograms in horizontal and vertical directions. Two types of model are used to fit these variograms: an exponential one, and a more complex model with ‘hole-effect’ in order to simulate channelling. 3D-stochastic hydraulic conductivity fields following these two spatial laws are generated using the geostatistical software ISATIS. These fields are then incorporated in the finite-elements code CASTEM2000 to lead to the associated flow fields. The transport is modelled by particle-tracking and Monte-Carlo techniques. The determination of the first and second order spatial moments leads to the dispersion coefficients. The simulated dispersivities are then compared to the experimental ones, and to the ones predicted by stochastic theories. The longitudinal dispersivity seems to reach an asymptotic limit after a 10 correlation lengths travel
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Courtois, Nathalie. "Caractérisation de la dispersion en aquifère hétérogène par méthodes de traçages et modélisation stochastique : Application à la nappe alluviale du Drac, à Grenoble." Paris, ENMP, 1999. http://www.theses.fr/1999ENMPA001.
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La dispersion à grande échelle en aquifère est principalement dominée par la structure spatiale du champ des perméabilités. L'objectif ici est de caractériser les propriétés dispersives de l'aquifère alluvial du Drac par deux approches basées sur l'utilisation de données expérimentales de traçage.
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Lion, Sébastien. "Structuration spatiale et évolution des populations." Paris 6, 2007. http://www.theses.fr/2007PA066354.
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Depuis une vingtaine d'années, le rôle de l'auto-structuration spatiale dans les processus évolutifs est devenu un point d'intérêt majeur en écologie évolutive. Parallèlement, le domaine de l'écologie spatiale a connu une véritable révolution avec l'introduction de nouvelles techniques de modélisation prenant en compte explicitement à la fois la structure spatiale et l'individualité. Le but de cette thèse est de comprendre comment l'interaction entre la dynamique écologique spatiale et l'évolution, grâce à une approche théorique qui combine simulations et modèles analytiques. Cette thèse a trois axes principaux. Dans une première partie, nous passons en revue les progrès théoriques que les modèles spatialisés les plus récents ont apportés à notre compréhension de l'évolution, et nous soulignons que la plupart des résultats se comprend mieux dans le cadre théorique plus large de la sélection multi-niveaux et de la sélection de parentèle. Dans un deuxième temps, nous développons un modèle pour l'évolution de populations structurées dans l'espace et en classes. Nous proposons une technique pour calculer la condition d'invasion d'un mutant rare au moyen d'équations de corrélations (ou approximation des paires), et l'appliquons à un modèle d'interactions entre adultes et jeunes. Ce modèle est adapté à l'étude de l'évolution des soins parentaux et du cannibalisme des jeunes, et nous permet de généraliser les conclusions d'études précédentes sur l'évolution de la coopération dans des populations visqueuses. En utilisant une méthodologie qui ne repose pas sur des approximations de la structure spatiale, nous donnons un éclairage sur les pressions de sélection qui s'appliquent sur les soins parentaux et le cannibalisme, et nous montrons qu'une variante de la règle de Hamilton émerge de la dynamique écologique spatiale. Nous montrons aussi que la forme des compromis évolutifs entre les traits démographiques est un facteur crucial qui détermine l'issue de l'évolution dans le modèle spatialisé, et que le rôle des corrélations spatiales d'ordre supérieur à trois peut avoir une importance quantitative subtile, maiOver the last two decades, the role of spatial self-structuring as a template for evolution has been a focus of increasing attention. At the same time, the field of spatial ecology has seen radical new developments with the advent of new modelling techniques that explicitely take into account both spatial structure and individuality. The aim of this thesis is to try an understand the interplay between spatial ecological dynamics and evolution, through a theoretical approach that uses both simulations and analytical models. The thesis unfolds along three axes. In a first part, we review the theoretical progress that the latest-spatially explicit models have brought to our understanding of evolution, and argue that most results are best understood in the larger framework of multilevel and kin selection. Secondly, we develop an analytical model for the evolution of populations that are structured both in space and in discrete classes. A technique to derive the invasion condition of a rare mutant is proposed using correlation equations (aka pair approximation), and applied to a model of juvenile-adult interactions. This model is adapted to the study of the evolution of parental care and juvenile cannibalism, and allows us to extend previous studies of the evolution of cooperation in viscous populations to altruistic interactions between different classes of individuals. Using a methodology that does not resort to approximations of the spatial structure, we shed light on the selective pressures on parental care and cannibalism, and show we can recover Hamilton's rule and relatedness as emergent properties of the spatial ecological dynamics. We also show that the shape of trade-off curves is crucial in determining the evolutionary outcome in the spatial model, and that in age-structured populations, the evolutionary role of higher-order spatial moments can be very subtle, but quantitatively important. Finally, we study the evolution of dispersal in host-parasite interactions. Evolution of the manipulation of host dispersal behaviour by parasites is shown to depend both on the scale of dispersal and on th
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Sloane, Mona. "Producing space : investigating spatial design practices in a market moment." Thesis, London School of Economics and Political Science (University of London), 2017. http://etheses.lse.ac.uk/3626/.
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This thesis is an investigation of commercial spatial design practices. It contributes to an emerging sociological and anthropological scholarship on design and is grounded in a studio ethnography of a large London-based architecture and spatial design practice. The analysis is based on an understanding of spatial design as conceptual, problem-solving and form-giving and focusses on the mediating role designers take on. It is framed by a pragmatist approach that highlights the significance of mediation, contextuality and agency in design as situated practice. The purpose of this project is to analyse the complicated set-up of spatial design as creative, material and commercial practice against the backdrop of distinct competitive and regulatory environments. Here, the “market moment” provides the empirical window for investigating how spatial design is premised on linking up creativity, space and commerce. The thesis suggests that studio studies are crucial for retrieving a humanist element in sociological interpretations of (spatial) design to help analyse the significance of materiality and commerciality within design as creative-conceptual work. In the context of an emerging and increasingly politicised design scholarship, this can provide avenues for examining the nuanced forms of design agency as well as design’s entanglement with existing and emerging socio-economic conditions.
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Ren, Kai. "Physics-Based Near-Field Microwave Imaging Algorithms for Dense Layered Media." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1511273574098455.
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Gonzalez, Marjorie Emily. "Spatial analysis of positron emission tomography images of Parkinson's disease using 3D moment invariants." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/43137.
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Positron emission tomography (PET) produces images of functional processes of the body in-vivo. The analysis of PET data for research purposes traditionally involves kinetic modeling of the concentration of the radiotracer over time within a region of interest (ROI) in the body to derive parameters related to the uptake/binding of the radiotracer in that region. PET imaging is commonly used to study Parkinson's disease (PD), where loss of motor function is caused by the progressive death of neurons in the brain that produce the neurotransmitter dopamine. In PD, both the kinetic and the spatial distribution of the tracer change due to the disease: the posterior parts of the striatum (in particular in the putamen) are affected before the anterior parts. The purpose of this dissertation is to develop a novel analysis method for PET data that uses the spatial characteristics of the radiotracer's distribution within anatomically-defined ROIs to extract additional information about pathological states. The proposed analysis method is based on mathematical 3D shape descriptors that are invariant to translation, scaling, and rotation, called 3D moment invariants (3DMIs). The variable of interest in this case is not only the radiotracer's uptake rate constant or binding potential, but also the 3D spatial shape and distribution of the radioactivity within the ROI. This dissertation shows that 3DMIs were able to successfully quantify differences in the spatial distribution of PET radiotracer images between healthy controls and PD subjects. 3DMI values were found to correlate with a clinical measure of disease severity in all anatomical regions studied here (putamen, caudate and ventral striatum), as opposed to kinetic parameters which only showed significant correlation to clinically-assessed PD severity in the putamen. Levodopa-induced changes in spatial patterns of dopamine release (as measured using 3DMIs) were found to be significantly correlated with PD severity in all ROIs studied here. These findings suggest that quantitative studies of a radiotracer's spatial distribution can be complementary to kinetic modeling in extracting information about pathological states from PET data and have the potential to contribute novel information in PET neuroimaging studies.
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Lück, Alexander Tobias [Verfasser]. "Stochastic spatial modelling of DNA methylation patterns and moment-based parameter estimation / Alexander Tobias Lück." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2020. http://d-nb.info/1219068659/34.
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Hilfiker, Stephen Glenn. "High-Resolution Spatial and Temporal Analysis of the Aftershock Sequence of the 23 August 2011 Mw 5.8 Mineral, Virginia, Earthquake." Thesis, Boston College, 2016. http://hdl.handle.net/2345/bc-ir:107179.
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Thesis advisor: John E. EbelStudies of aftershock sequences in the Central Virginia Seismic Zone (CVSZ) provide critical details of the subsurface geologic structures responsible for past and (possibly) future earthquakes in an intraplate setting. The 23 August 2011 MW 5.8 Mineral, Virginia, earthquake, the largest magnitude event recorded in the CVSZ, caused widespread damage and generated a lengthy and well-recorded aftershock sequence. Over 1600 aftershocks were recorded using a dense network of seismometers in the four months following the mainshock, offering the unique opportunity to study the fault structure responsible for the post-main event seismicity. Previous work has not accurately determined the geometry of the fault structure or the migration of post-mainshock seismicity and association of the 2011 event with a known fault has been unsuccessful. In this study, relative locations of recorded aftershocks were calculated using a version of the double-difference location method outlined in Ebel et al. (2008) to generate an accurate model of the fault structure. The moment tensor inversion technique of Ebel and Bonjer (1990) was used to generate focal mechanisms of dozens of the aftershocks at various locations on the fault structure. Results from the double-difference and moment tensor inversion methods were used to map the structure responsible for the aftershock sequence in high resolution. The calculated fault structure has planes with similar strikes and dips as known faults and geologic structures in the CVSZ. In-depth analysis of this aftershock sequence provides seismologists with the opportunity to better understand the seismic hazards present in poorly understood intraplate seismic zones
Thesis (MS) — Boston College, 2016
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Earth and Environmental Sciences
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Hartz, Andrew Scott. "Lab Scale Hydraulic Parameter Estimation." Thesis, The University of Arizona, 2011. http://hdl.handle.net/10150/203499.
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Hydraulic tomography has been tested at the field scale, lab scale and in synthetic experiments. Recently Illman and Berg have conducted studies at the lab scale. Using their data hydraulic tomography can be compared to homogeneous anisotropic solutions using one pumping well or multiple pumping wells. It has been found that hydraulic tomography out performs homogenous methods at predicting hydraulic head for validation pumping experiments. Also it has been shown in this study that homogenous anisotropic tests exhibit scenario dependent behavior. Additional tests performed to further validate the conclusions made in this experiment include spatial moment analysis, response surface analysis, and synthetic hydraulic tomography and show consistent results providing additional validation of these findings. Additional study examining the principle of reciprocity has proven inconclusive.
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Warren, Justin Cable. "A Study of Mine-Related Seismicity in a Deep Longwall Coal Mine." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/76766.
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This study involves seismic monitoring of a deep coal mine. The purpose is to examine the processes responsible for induced seismicity. A seismic network consisting of five three-component short-period seismometers located above the mine recorded the seismic data. The events discussed here occurred from March 1, 2009 until April 7, 2011 during the mining of three longwall panels and the data was telemetered to Blacksburg, Virginia.
A correlation equation was developed to relate local magnitude estimated by automatic data processing software in near real-time to seismic moment for well-recorded events. Local magnitude is a relative measure of relative size for a suite of earthquakes, while seismic moment is an objective measure of the actual physical size. Using the calculated seismic moments, we calculated "moment magnitudes" (Mw) for all events, which allowed us to do further studies in terms of their absolute size as a function of both time and space.
The results indicate that there are two distinct classes of seismic events at the mine. The first class consists of small (M<=0) earthquakes recorded near the moving mine face. The second class of seismicity occurs in the mined-out "gob" area of the longwall panel at a greater distance behind the moving face. Their occurrence and relation to the mining history, depth of overburden and geology of the roof rocks is a significant interest.
Results show that thick overburden due to elevated topography has a positive correlation with the number of seismic events but is not the only controlling factor; other factors include gob size and geological variability. Another important observation is the high seismic attenuation of the rock mass above the mine. This appears to be the result of the fracturing and caving processes associated with the creation of the gob and the resulting subsidence of the ground surface.Master of Science
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Cooper, James Russell. "Spatially-induced momentum transfer over water-worked gravel beds." Thesis, University of Sheffield, 2007. http://etheses.whiterose.ac.uk/15018/.
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The spatial variability in turbulent flows over water-worked gravel beds has been studied. Spatially distributed measurements of velocity were obtained using Particle Image Velocimetry for a range of hydraulic conditions over two water-worked gravel beds. A different approach to bed formation was achieved by feeding sediment into a flume to form deposits that result from the, arrangement of the grains by the flow, as would be observed in a river. It was shown that, even over macroscopically flat deposits, time-averaged streamwise velocities display considerable spatial variability. However, the level of variability was a magnitude lower for time-averaged vertical velocities. The degree of spatial variability in both streamwise and vertical velocities was shown to increase with relative submergence. Spatial flow variability was present in the logarithmic and outer regions of the flow, which contradicts previous thinking that spatial variability is only present in the near bed form-induced sublayer. The time-averaged flow velocities displayed a considerable degree of organisation over both beds, indicating the existence of spatially coherent time-averaged flow structures. Form-induced stresses caused by the spatial heterogeneity in the flow were estimated. These were found to be significant for flows over both beds, and did not disappear above the form-induced sub layer as previously thought. Measurements of Reynolds stress alone, whether spatially-averaged or not, cannot be used to determine the mean bed shear stress over water-worked gravel beds. Increases in relative submergence resulted in changes in the level of momentum carried by spatial deviations in the flow, and by inference, those carried by the turbulent fluctuations. This occurred even when the average rate of momentum transfer at the bed was the same. It was concluded that relative submergence could have a more important influence on the spatial variability of fluid stresses than the bed surface topography of water-worked gravel deposits.
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Tandjè, Sourou Hugues Arsène. "Conception et caractérisation de fibres optiques à modes à moment angulaire orbital." Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1R032/document.
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Les fibres optiques (qu’elles soient à saut ou à gradient d'indice) sont largement utilisées pour les liaisons longue (intercontinentale, dorsale optique terrestre) et courte portée (centre de données, réseau d'accès). Certaines fibres, appelées fibres optiques de spécialité, jouent également un rôle important dans d'autres domaines telles que la médecine (endoscopie par exemple), les capteurs, les applications au laser, etc. La multiplication constante des services Internet combinée à la croissance du nombre d'utilisateurs rend nécessaire l'augmentation de la capacité actuelle des réseaux à fibres optiques. Les fibres aujourd’hui installées et utilisées pour les transmissions à très haut débit utilisent uniquement le mode fondamental (noté LP01, dans l'approximation de faible guidage) pour transmettre les informations : on parle de fibres optiques monomodes. Comme ils atteignent maintenant la limite non-linéaire de Shannon, une des idées pour augmenter la capacité des réseaux optiques consiste à mettre en œuvre le multiplexage spatial (SDM) et à utiliser simultanément différents modes dans une fibre dite légèrement multimode (supportant généralement quelques dizaines de modes) ou une fibre multi-cœurs. Depuis 2010, plusieurs études ont été développées dans ce sens, principalement sur les fibres supportant les modes LP (Linéairement Polarisés) et, plus récemment, les modes OAM (moment angulaire orbital), c’est-à-dire des modes à polarisation circulaire et à phase hélicoïdale. Dans ce dernier cas, les propriétés de phase et de polarisation sont supposées limiter le couplage entre les modes. Ce travail de thèse porte sur la conception et la réalisation de fibres OAM présentant un couplage faible entre modes, pour une application au transport de données mais également pour une étude en photonique non-linéaire. Certaines des fibres étudiées sont des fibres à cœur annulaire fabriquées selon les méthodes de fabrication conventionnelles, présentant des rayons interne / externe et des indices d’anneau optimisés. Nous avons fabriqué de telles fibres à cœur annulaire toute solide dans le but de les appliquer pour une transmission MIMO simple en utilisant des modes OAM comme des canaux indépendants. Cependant, nous avons également conçu et fabriqué la première fibre à cristal photonique (PCF) avec un cœur annulaire quasi-circulaire, à faible perte par confinement et adaptée au guidage des modes OAM. Nous avons montré expérimentalement que les fibres fabriquées supportent les modes OAM et leurs matrices de transmission ont été mesurées. Nous avons également effectué des expérimentations préliminaires sur le décalage solitonique dans la fibre PCF supportant les modes OAMOptical fibers (step index and graded-index ones) are widely used for long-haul (intercontinental, terrestrial optical backbone) and short-reach (datacenter, access network) links. Some fibers called specialty optical fibers also play an important role in other applications like medicine (endoscopy for example), sensing, laser applications etc. The constant rise of Internet services combined to the growth of the number of Internet users makes it necessary to increase the current capacity of optical fiber networks. The fibers commercially used today for very high data rate transmissions use only the fundamental mode (denoted LP01, in the weakly guiding approximation) to transmit the information: there are known as single-mode fibers. As they are now reaching the so-called nonlinear Shannon limit, one of the ideas for increasing the capacity of fiber networks is to implement space-division multiplexing (SDM) and then simultaneously use different modes in a so-called few-mode fiber (fiber supporting typically dozens of modes) or a multicore fiber. Since 2010, several studies have been developed in this direction, mainly on fibers supporting LP (Linearly Polarized) modes and more recently OAM (Orbital Angular Momentum) modes, i.e. modes with helical phase and circular polarization. In this last case, phase and polarization properties are supposed to limit the coupling between modes. This PhD work deals with the design and the realization of OAM fibers presenting weak coupling between modes, for application to data transport but also for study in nonlinear photonics. Some of the fibers studied are annular core fibers made by conventional manufacturing methods, having internal / external radii and optimized ring refractive indices. We fabricated such all-solid ring-core fibers with the aim to apply them for simple MIMO transmission using OAM modes as independent channels. However, we also designed and manufactured the first photonic crystal fiber (PCF) with close-to-circular ring-core, low confinement loss and suitable for OAM mode guidance. We experimentally show that the fabricated fibers support OAM modes, and their transmission matrices have been measured. We also performed preliminary solitonic shifting experimentations in PCF fiber supporting OAM
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Maia, Marcelo Reis. "Cidade instantânea (IC)." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/16/16134/tde-03072013-162823/.
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Sugere-se a hipótese de uma Cidade Instantânea identificada no cotidiano em situações condicionadas por tecnologias de comunicação e informação, e especialmente a computação ubíqua, também conhecida como computação pervasiva ou computação ambiente. A investigação aponta para o entendimento de uma Cidade Instantânea que emerge em coletivos sem escala, sem localização e com fronteiras e limites extremamente frágeis, fluidos e temporários. A Cidade Instantânea se infiltra em todas as formas de cidades existentes sem anulá-las; substituí-las. A Cidade Instantânea não tem um objetivo traçado, ela é pura subjetividade que ganha força e presença nas multidões de indivíduos conectados.We suggest the hypothesis of an Instant City identified in everyday situations conditioned by information and communication technologies, especially the ubiquitous computing, also known as pervasive computing or ambient computing. The research points to the understanding of an Instant City that emerges in collectives without a precise scale or location, with extremely fragile, fluid and temporary boundaries and limits. The Instant City joins and infiltrate in all forms of existing cities without dismiss them; replace them. The Instant City is pure subjectivity that gains strength and presence in the crowds of connected individuals.
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McLaren, Melanie. "Tailoring quantum entanglement of orbital angular momentum." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/95868.
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Thesis (PhD)--Stellenbosch University, 2014.ENGLISH ABSTRACT: High-dimensional quantum entanglement offers an increase in information capacity per photon; a highly desirable property for quantum information processes such as quantum communication, computation and teleportation. As the orbital angular momentum (OAM) modes of light span an infinite-dimensional Hilbert space, they have become frontrunners in achieving entanglement in higher dimensions. In light of this, we investigate the potential of OAM entanglement of photons by controlling the parameters in both the generation and measurement systems. We show the experimental procedures and apparatus involved in generating and measuring entangled photons in two-dimensions. We verify important quantum tests such as the Einstein, Podolsky and Rosen (EPR) paradox using OAM and angle correlations, as well as a violation of a Bell-type inequality. By performing a full state tomography, we characterise our quantum state and show we have a pure, highly entangled quantum state. We demonstrate that this method can be extended to higher dimensions. The experimental techniques used to generate and measure OAM entanglement place an upper bound on the number of accessible OAM modes. As such, we investigate new methods in which to increase the spiral bandwidth of our generated quantum state. We alter the shape of the pump beam in spontaneous parametric down-conversion and demonstrate an effect on both OAM and angle correlations. We also made changes to the measurement scheme by projecting the photon pairs into the Bessel-Gaussian (BG) basis and demonstrate entanglement in this basis. We show that this method allows the measured spiral bandwidth to be optimised by simply varying the continuous radial parameter of the BG modes. We demonstrate that BG modes can be entangled in higher dimensions compared with the commonly used helical modes by calculating and comparing the linear entropy and fidelity for both modes. We also show that quantum entanglement can be accurately simulated using classical light using back-projection, which allows the study of projective measurements and predicts the strength of the coincidence correlations in an entanglement experiment. Finally, we make use of each of the techniques to demonstrate the effect of a perturbation on OAM entanglement measured in the BG basis. We investigate the self-healing property of BG beams and show that the classical property is translated to the quantum regime. By calculating the concurrence, we see that measured entanglement recovers after encountering an obstruction.
AFRIKAANSE OPSOMMING: Hoë-dimensionele kwantumverstrengeldheid bied ’n toename in inligtingskapasiteit per foton. Hierdie is ’n hoogs wenslike eienskap vir kwantum inligting prosesse soos kwantum kommunikasie, berekening en teleportasie. Omdat die orbitale hoekmomentum (OAM) modusse van lig ’n oneindig dimensionele Hilbertruimte beslaan, het dit voorlopers geword in die verkryging van verstrengeling in hoër dimensies. In die lig hiervan, ondersoek ons die potensiaal van OAM verstrengeling van fotone deur die parameters in beide die generering en meting stelsels te beheer. Ons toon die eksperimentele prosedures en apparaat wat betrokke is by die generering en die meet van verstrengelde fotone in twee dimensies. Ons verifieer kwantumtoetse, soos die Einstein, Podolsky en Rosen (EPR) paradoks vir OAM en die hoekkorrelasies, sowel as ’n skending van ’n Bell-tipe ongelykheid. Deur middel van ’n volledige toestand tomografie, karakteriseer ons die kwantum toestand en wys ons dat dit ’n suiwer, hoogs verstrengel kwantum toestand is. Ons toon ook dat hierdie metode uitgebrei kan word na hoër dimensies. Die eksperimentele tegnieke wat tydens die generasie en meet van OAM verstrengeling gebruik is, plaas ’n bogrens op die aantal toeganklik OAM modusse. Dus ondersoek ons nuwe metodes om die spiraal bandwydte van ons gegenereerde kwantum toestand te verhoog. Ons verander die vorm van die pomp bundel in spontane parametriese af-omskakeling en demonstreer die uitwerking daarvan op beide OAM en die hoekkorrelasies. Ons het ook veranderinge aan die meting skema gemaak deur die foton pare op die Bessel-Gauss (BG) basis te projekteer. Ons wys dat hierdie metode die gemeetde spiraal bandwydte kan optimeer deur eenvoudig die kontinue radiale parameter van die BG modes te verander. Ons demonstreer dat BG modusse verstrengel kan word in hoër dimensies as die heliese modusse, wat algemeen gebruik word, deur berekeninge te maak en te vergelyk met lineêre entropie en vir beide modusse. Ons wys ook dat kwantumverstrengling akkuraat nageboots kan word, met behulp van die klassieke lig terug-projeksie, wat die studie van projeksie metings toelaat en voorspel die krag van die saamval korrelasies in ’n verstrengeling eksperiment. Ten slotte, gebruik ons elk van die tegnieke om die effek van ’n storing op OAM verstrengling wat in die BG basis gemeet is, te demonstreer. Ons ondersoek die self-genesingseienskap van BG bundels en wys dat die klassieke eienskap vertaal na die kwantum-gebied. Deur die berekening van die konkurrensie (concurrence), sien ons dat die gemeetde verstrengeling herstel word nadat ’n obstruksie ondervind is.
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Daviau, Jean-Luc. "Spatially explicit regional flood frequency analysis using L-moment, GIS and geostatistical methods." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq36680.pdf.
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Brunet, Charles. "Design and modeling of optical fibers for spatial division multiplexing using the orbital angular momentum of light." Doctoral thesis, Université Laval, 2016. http://hdl.handle.net/20.500.11794/26996.
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Les besoins toujours croissants en terme de transfert de données numériques poussent au développement de nouvelles technologies pour accroître la capacité des réseaux, notamment en ce qui concerne les réseaux de fibre optique. Parmi ces nouvelles technologies, le multiplexage spatial permet de multiplier la capacité des liens optiques actuels. Nous nous intéressons particulièrement à une forme de multiplexage spatial utilisant le moment cinétique orbital de la lumière comme base orthogonale pour séparer un certain nombre de canaux. Nous présentons d’abord les notions d’électromagnétisme et de physique nécessaires à la compréhension des développements ultérieurs. Les équations de Maxwell sont dérivées afin d’expliquer les modes scalaires et vectoriels de la fibre optique. Nous présentons également d’autres propriétés modales, soit la coupure des modes, et les indices de groupe et de dispersion. La notion de moment cinétique orbital est ensuite introduite, avec plus particulièrement ses applications dans le domaine des télécommunications. Dans une seconde partie, nous proposons la carte modale comme un outil pour aider au design des fibres optiques à quelques modes. Nous développons la solution vectorielle des équations de coupure des modes pour les fibres en anneau, puis nous généralisons ces équations pour tous les profils de fibres à trois couches. Enfin, nous donnons quelques exemples d’application de la carte modale. Dans la troisième partie, nous présentons des designs de fibres pour la transmission des modes avec un moment cinétique orbital. Les outils développés dans la seconde partie sont utilisés pour effectuer ces designs. Un premier design de fibre, caractérisé par un centre creux, est étudié et démontré. Puis un second design, une famille de fibres avec un profil en anneau, est étudié. Des mesures d’indice effectif et d’indice de groupe sont effectuées sur ces fibres. Les outils et les fibres développés auront permis une meilleure compréhension de la transmission dans la fibre optique des modes ayant un moment cinétique orbital. Nous espérons que ces avancements aideront à développer prochainement des systèmes de communications performants utilisant le multiplexage spatial.The always increasing need for digital data bandwidth pushes the development of emerging technologies to increase network capacity, especially for optical fiber infrastructures. Among those technologies, spatial multiplexing is a promising way to multiply the capacity of current optical links. In this thesis, we are particularly interested in current spatial multiplexing using the orbital angular momentum of light as an orthogonal basis to distinguish between a few optical channels. We first introduce notions from electromagnetism and physic needed for the understanding of the later developments. We derive Maxwell’s equations describing scalar and vector modes of optical fiber. We also present other modal properties like mode cutoff, group index, and dispersion. Orbital angular momentum is briefly explained, with emphasis on its applications to optical communications. In the second part, we propose the modal map as a tool that can help in the design of few mode fibers. We develop the vectorial solution of the ring-core fiber cutoff equation, then we extend those equations to all varieties of three-layer fiber profiles. Finally, we give some examples of the use of the modal map. In the third part of this thesis, we propose few fiber designs for the transmission of modes with an orbital angular momentum. The tools that were developed in the second part of this thesis are now used in the design process of those fibers. A first fiber design, characterized by a hollow center, is studied and demonstrated. Then a second design, a family of ring-core fibers, is studied. Effective indexes and group indexes are measured on the fabricated fibers, and compared to numerical simulations. The tools and the fibers developed in this thesis allowed a deeper comprehension of the transmission of orbital angular momentum modes in fiber. We hope that those achievements will help in the development of next generation optical communication systems using spatial multiplexing.
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Benzougar, Abdeljabar. "Perception de la profondeur en stéréovision monoculaire par exploitation du flou optique : approche basée sur les moments spatiaux." Poitiers, 1997. http://www.theses.fr/1997POIT2301.
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Nous proposons une nouvelle methode de stereovision monoculaire par exploitation du flou optique. L'objectif de cette methode est le calcul de la carte des profondeurs d'une scene reelle par la mesure du flou optique existant sur les objets qui constituent cette scene. La mesure que nous proposons est basee sur la technique des moments spatiaux. Le moment spatial monodimensionnel d'ordre deux est estime sur la derivee de l'image floue, dans la direction du gradient. Cette estimation se decompose alors en deux composantes. Une premiere composante est liee au profil de l'image nette, la seconde est le moment d'ordre deux de la reponse impulsionnelle du systeme optique. La methode proposee ne requiert aucune modelisation ni de la reponse impulsionnelle ni du profile de luminance de l'image nette. Le systeme de stereovision developpe utilise deux images floues de la meme scene, acquises avec deux ouvertures differentes. Les resultats experimentaux montrent que, non seulement la faisabilite d'une mesure de la profondeur par une approche exploitant le flou optique est effective, mais que les performances obtenues sont comparables a celles obtenues par d'autres methodes.
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Kupper, Mireille. "Estimation et modélisation du lien entre deux processus à indices dans ℤ², et applications à l'épidémiologie." Paris 11, 1985. http://www.theses.fr/1985PA112313.
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Etude de différents estimateurs de la tendance et des corrélations d'un processus bivarié gaussien à indices dans ℤ², à tendance linéaire en un paramètre et à covariance stationnaire : estimateurs du maximum de vraisemblance exacte et approchée, estimateurs empiriques. Etude d'un modèle de régression avec structure spatiale pour le processus gaussien bivarié à indices dans ℤ² précisant la forme du lien entre la première et la seconde composantes du processus. Application à un exemple d’épidémiologie : recherche du lien entre un facteur donné (taux d'alcoolisme/département français) et la prévalence d'une maladie (taux de mort par cancer de l'œsophage/département français), en modélisant le facteur et la maladie par un processus bivarié indexé par ℤ²Study of some estimators of the trend and the correlations of a Gaussian bivariate process indexed by ℤ² with a linear trend and stationary covariances, such as the exact or approximated maximum likelihood estimators and the empirical estimators. Study of a regression model with spatial structure for the Gaussian bivariate process indexed by ℤ² specifying the form of the relation between the first and second components of the process. Application to an epidemiological example: the research of the relation between a given factor (alcoholism _rate/French department) and the prevalence of a disease (death rate of esophagus cancer/French department) by modelling the factor and the disease with a bivariate process indexed by ℤ²
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Chhang, Sophy. "Energy-momentum conserving time-stepping algorithms for nonlinear dynamics of planar and spatial euler-bernoulli/timoshenko beams." Thesis, Rennes, INSA, 2018. http://www.theses.fr/2018ISAR0027/document.
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Dans la première partie de la thèse, les schémas d’intégration conservatifs sont appliqués aux poutres co-rotationnelles 2D. Les cinématiques d'Euler-Bernoulli et de Timoshenko sont abordées. Ces formulations produisent des expressions de l'énergie interne et l'énergie cinétique complexe et fortement non-linéaires. L’idée centrale de l’algorithme consiste à définir, par intégration, le champ des déformations en fin de pas à partir du champ de vitesses de déformations et non à partir du champ des déplacements au travers de la relation déplacement-déformation. La même technique est appliquée aux termes d’inerties. Ensuite, une poutre co-rotationnelle plane avec rotules généralisées élasto-(visco)-plastiques aux extrémités est développée et comparée au modèle fibre avec le même comportement pour des problèmes d'impact. Des exemples numériques montrent que les effets de la vitesse de déformation influencent sensiblement la réponse de la structure. Dans la seconde partie de cette thèse, une théorie de poutre spatiale d’Euler-Bernoulli géométriquement exacte est développée. Le principal défi dans la construction d’une telle théorie réside dans le fait qu’il n’existe aucun moyen naturel de définir un trièdre orthonormé dans la configuration déformée. Une nouvelle méthodologie permettant de définir ce trièdre et par conséquent de développer une théorie de poutre spatiale en incorporant l'hypothèse d'Euler- Bernoulli est fournie. Cette approche utilise le processus d'orthogonalisation de Gram-Schmidt couplé avec un paramètre rotation qui complète la description cinématique et décrit la rotation associée à la torsion. Ce processus permet de surmonter le caractère non-unique de la procédure de Gram-Schmidt. La formulation est étendue au cas dynamique et un schéma intégration temporelle conservant l'énergie est également développé. De nombreux exemples démontrent l’efficacité de cette formulationIn the first part of the thesis, energymomentum conserving algorithms are designed for planar co-rotational beams. Both Euler-Bernoulli and Timoshenko kinematics are addressed. These formulations provide us with highly complex nonlinear expressions for the internal energy as well as for the kinetic energy which involve second derivatives of the displacement field. The main idea of the algorithm is to circumvent the complexities of the geometric non-linearities by resorting to strain velocities to provide, by means of integration, the expressions for the strain measures themselves. Similarly, the same strategy is applied to the highly nonlinear inertia terms. Next, 2D elasto-(visco)-plastic fiber co-rotational beams element and a planar co-rotational beam with generalized elasto-(visco)-plastic hinges at beam ends have been developed and compared against each other for impact problems. In the second part of this thesis, a geometrically exact 3D Euler-Bernoulli beam theory is developed.The main challenge in defining a three-dimensional Euler-Bernoulli beam theory lies in the fact that there is no natural way of defining a base system at the deformed configuration. A novel methodology to do so leading to the development of a spatial rod formulation which incorporates the Euler-Bernoulli assumption is provided. The approach makes use of Gram-Schmidt orthogonalisation process coupled to a one-parametric rotation to complete the description of the torsional cross sectional rotation and overcomes the non-uniqueness of the Gram-Schmidt procedure. Furthermore, the formulation is extended to the dynamical case and a stable, energy conserving time-stepping algorithm is developed as well. Many examples confirm the power of the formulation and the integration method presented
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Chu, Jiaqi. "Orbital angular momentum encoding/decoding of 2D images for scalable multiview colour displays." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/274903.
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Three-dimensional (3D) displays project 3D images that give 3D perceptions and mimic real-world objects. Among the rich varieties of 3D displays, multiview displays take advantage of light’s various degrees of freedom and provide some of the 3D perceptions by projecting 2D subsampling of a 3D object. More 2D subsampling is required to project images with smoother parallax and more realistic sensation. As an additional degree of freedom with theoretically unlimited state space, orbital angular momentum (OAM) modes may be an alternative to the conventional multiview approaches and potentially project more images. This research involves exploring the possibility of encoding/decoding off-axis points in 2D images with OAM modes, development of the optical system, and design and development of a multiview colour display architecture. The first part of the research is exploring encoding/decoding off-axis points with OAM modes. Conventionally OAM modes are used to encode/decode the on-axis information only. Analysis of on-axis OAM beams referenced to off-axis points suggests representation of off-axis displacements as a set of expanded OAM components. At current stage off-axis points within an effective coding area are possible to be encoded/decoded with chosen OAM modes for multiplexing. Experimentally a 2D image is encoded/decoded with an OAM modes. When the encoding/decoding OAM modes match, the image is reconstructed. On the other hand, a dark region with zero intensity is shown. The dark region suggests the effective coding area for multiplexing. The final part of the research develops a multiview colour display. Based on understandings of off-axis representation of a set of different OAM components and experimental test of the optical system, three 1 mm monochromatic images are encoded, multiplexed and projected. Having studied wavelength effects on OAM coding, the initial architecture is updated to a scalable colour display consisting of four wavelengths.
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Neale, Dennis Clay. "Spatial perception on perspective displays as a function of field-of-view and virtual environment enhancements based on visual momentum techniques." Thesis, This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-01312009-063242/.
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Diallo, Abdourahmane. "Théorie et estimation des modèles spatiaux à choix discret : application aux modèles d'occupation du sol en région PACA." Paris, EHESS, 2014. http://www.theses.fr/2014EHES0167.
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Nous nous intéressons à la théorie et à l'estimation des modèles spatiaux à choix discret afin de développer des techniques d'estimation pour analyser les décisions de changements d'usage du sol sur gros échantillon. Nous établissons des propriétés limites d'estimateurs des paramètres inconnus de ces modèles dans un contexte de processus non stationnaire. Le Chapitre 1 rassemble des rappels sur les résultats de la théorie de l'estimation des modèles spatiaux à choix discret, qui seront essentiels dans les chapitres suivants. Dans le Chapitre 2, nous montrons un résultat de théorème limite et l'utilisons pour démontrer la convergence presque sure et la normalité asymptotique des estimateurs proposés dans les Chapitres 3 et 4. Le Chapitre 3 traite l'extension de la méthode proposée par KLIER et MCMILLEN (2008) au cas où le modèle inclut à la fois une variable dépendante et des termes de perturbation spatialement décalés. Le Chapitre 4 étend les techniques développées au Chapitre 3 au cas multinomial et sur données de panelIn this thesis, we propose and discuss some spatial discrete choice models that rely on the theory of random utility model, as well as some limit theorems. Although several estimation methods already exist - like likelihood maximization methods (LM) which consider ail the available information in the samples - we propose an approach by the generalized method of moments (GMM) to estimate the unknown parameters of these models. We start by recalling the theoretical results and estimate approaches of spatial discrete choice models that are going to be essential in the other chapters. In Chapter 2, we provide results of a central limit theorem in order to prove the consistency and the asymptotic normality of the estimators proposed in Chapters 3 and 4. The Chapter 3 extends KLIER and MCMILLEN's method in the case of a model that includes both a dependent variable and disturbances terms spatially lagged. Chapter 4 derives the multinomial case and panels data spatially lagged. Chapter 4 derives the multinomial case and panels data
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Naidoo, Darryl. "High brightness lasers." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97044.
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Kubické, Gildas. "Contribution au calcul de la diffusion d'une onde électromagnétique par des réflecteurs polyédriques au-dessus d'une surface rugueuse." Nantes, 2008. http://www.theses.fr/2008NANT2026.
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Ce travail a pour cadre la diffusion d'une onde électromagnétique par des réflecteurs polyédriques localisés au-dessus d'une surface océanique rugueuse. L'étude est d'abord menée pour une scène invariante selon une dimension de l'espace (cas 2D) composée d’une surface rugueuse ; des modèles dits « exacts » et rapides sont alors investigués. La diffraction par un objet de forme quelconque puis par un réflecteur pour le cas scalaire, ramené à un obstacle cruciforme, est ensuite investiguée. La Méthode des Moments est utilisée comme méthode de référence pour valider le modèle asymptotique analytique combinant l'Optique Physique et l'Optique Géométrique. Fort de ces résultats, un formalisme rigoureux pour une scène bidimensionnelle composée d'un objet au-dessus d'une surface rugueuse est utilisé. Les méthodes numériques rapides étudiées pour le cas « surface seule » sont appliquées à l’aide d’une méthode itérative utilisant un développement en série. Toujours dans le souci de diminuer la complexité de la méthode, l'Optique Physique est appliquée numériquement sur l'objet ; le modèle hybride ainsi obtenu est comparé au modèle de référence sur une surface de mer dans le domaine micro-ondes. Enfin, un modèle asymptotique analytique, similaire à celui proposé pour la croix dans le cas 2D, est développé, mais en 3D, pour calculer le champ diffracté par des réflecteurs polyédriques (trièdre, octaèdre, icosaèdre) placés en espace libre. Finalement, après l'étude de la validité de ce modèle, des propriétés intrinsèques de ces réflecteurs sont dégagéesThis work's topic is the electromagnetic wave scattering from polyhedral reflectors located above a rough surface. First, the study is focused on the scattering from a monodimensional rough surface (2D case) and the problem is solved exactly by means of fast numerical methods. For the scalar problem, the scattering from the reflector, assimilated to a cross-shaped object, is then investigated. The Method of Moments is used as a benchmark method to validate the asymptotic analytic model based on the Physical Optics and the Geometrical Optics approximations. A rigorous formalism for a bidimensional scene composed by a scatterer located above a rough surface is then used. The fast numerical methods used for the case of a rough surface without the object can be applied by means of an iterative solution using series expansion. In order to decrease the complexity of this new numerical method, Physical Optics is applied on the cross. The hybrid model is then compared with the benchmark method for maritime scenarios. Then, an analytic asymptotic model, similar to the one proposed for the cross for the 2D case, is developped in the 3D case for the diffraction from a polyhedral reflector in free space. Finally, the validity of this model is discussed and intrinsec properties of the reflectors are underlined
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Banos, Arnaud. "Le lieu, le moment, le mouvement : pour une exploration spatio-temporelle désagrégée de la demande de transport en commun en milieu urbain." Besançon, 2001. http://www.theses.fr/2001BESA1017.
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L'évolution des conditions de déplacement a considérablement modifié et complexifié les territoires de la mobilité quotidienne. Toujours plus nombreux, les mobiles urbains irriguent en permanence cette trame urbaine faite pour et par l'automobile, consommant des espaces plus étendus qu'auparavant. Le transport public de voyageurs peine à s'ajuster à ces nouvelles configurations spatiales et temporelles. Un repositionnement stratégique semble toutefois être amorcé, fondé sur l'individualisation de l'offre du transport public, collective par définition et par tradition. Dans ce contexte, la recherche menée vise à proposer un protocole d'estimation de la demande rationnel, fiable et reproductible, à même de révéler finement cette demande individuelle, multiforme et volatile. Reposant sur une combinaison d'enquêtes géomarketing adaptatives, la procédure d'innovation concertée élaborée implique les individus observés dans le processus même d'innovation,. . .
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Narváez, Castañeda Emmanuel. "Elliptical Vortex Beams Through Turbulent Atmosphere." University of Dayton / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1608232137775185.
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Kung, Ping-cheng, and 龔炳丞. "New Content-based Image Retrieval Using Spatial Chromaticity Moments." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/2d4mzy.
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碩士國立臺灣科技大學
資訊工程系
94
Based on the chromaticity moments (CMs), recently Paschos presented a memory-saving image retrieval (IR) algorithm called the CMIR algorithm. In this thesis, based on the proposed concept of spatial CMs (SCMs), a novel and efficient spatial-based CMIR (SCMIR) algorithm is presented. Besides preserving the original memory-saving advantage in the currently published CMIR algorithm, our proposed SCMIR algorithm has better retrieval accuracy due to embedding the spatial information into the CMs. Based on two hundred and twenty-five color images as the image database, experimental results confirm the better retrieval accuracy and the memory-saving preservation of our proposed SCMIR algorithm.
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Jovanovic, Stefan. "Virtual moments : social and spatial histories re-imagined in a video installation by Stan Douglas." Thesis, 2002. http://spectrum.library.concordia.ca/1774/1/MQ72972.pdf.
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This study focuses on a single work within the oeuvre of the Canadian artist Stan Douglas, the two-channel video installation Win, Place or Show (1998). This piece is constructed as an infinitely-looping counterfactual narrative, set in a modernist social-housing unit in late-1960s Vancouver that was never in fact built. Two dockworkers inhabiting a cramped one-bedroom unit in this imaginary setting repeatedly argue, fight and reconcile, while our view of this action--filmed from twelve different camera angles--is randomized by a computer in real time as the story unfolds and repeats. My study will consider this work within a twofold problematic; firstly, the themes and strategies that form the work's conceptual basis will be examined and situated within an art-historical context, with respect to their correspondences within the whole of Douglas's body of work and the broader context of Vancouver-based photo-conceptual practices over the past several decades. Subsequently, the work will be analyzed within a range of theories respecting the concepts of space, time and their relation to the construction of narrative and visual culture, and by extension, to the production of everyday consciousness.
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Alqasrawi, Yousef T. N., Daniel Neagu, and Peter I. Cowling. "Fusing integrated visual vocabularies-based bag of visual words and weighted colour moments on spatial pyramid layout for natural scene image classification." 2013. http://hdl.handle.net/10454/9604.
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NoThe bag of visual words (BOW) model is an efficient image representation technique for image categorization and annotation tasks. Building good visual vocabularies, from automatically extracted image feature vectors, produces discriminative visual words, which can improve the accuracy of image categorization tasks. Most approaches that use the BOW model in categorizing images ignore useful information that can be obtained from image classes to build visual vocabularies. Moreover, most BOW models use intensity features extracted from local regions and disregard colour information, which is an important characteristic of any natural scene image. In this paper, we show that integrating visual vocabularies generated from each image category improves the BOW image representation and improves accuracy in natural scene image classification. We use a keypoint density-based weighting method to combine the BOW representation with image colour information on a spatial pyramid layout. In addition, we show that visual vocabularies generated from training images of one scene image dataset can plausibly represent another scene image dataset on the same domain. This helps in reducing time and effort needed to build new visual vocabularies. The proposed approach is evaluated over three well-known scene classification datasets with 6, 8 and 15 scene categories, respectively, using 10-fold cross-validation. The experimental results, using support vector machines with histogram intersection kernel, show that the proposed approach outperforms baseline methods such as Gist features, rgbSIFT features and different configurations of the BOW model.