The production or comprehension of linguistic information is often not an isolated task decoupled from the visual environment. Rather, people refer to objects or listen to other people describing objects around them. Previous studies have shown that in such situations people either fixate these objects, often multiple times (Cooper, 1974), or they attend to the objects much longer than is required for mere identification (Meyer, Sleiderink, & Levelt, 1998). Most interestingly, during comprehension people also attend to the location of objects even when those objects were removed (Altmann, 2004). The main focus of this thesis was to investigate the role of the spatial location of objects during language processing. The first part of the thesis tested whether attention to objects’ former locations facilitates language production and comprehension processes (Experiments 1-­‐5). In two initial eye-­‐tracking experiments, participants were instructed to name objects that either changed their positions (Experiment 1) or were withdrawn from the computer screen (Experiment 2) during language production. Production was impaired when speakers did not attend to the original position of the objects. Most interestingly, fixating an empty region in which an object was located resulted in faster articulation and initiation times. During the language comprehension tasks, participants were instructed to evaluate facts presented by talking heads appearing in different positions on the computer screen. During evaluation, the talking heads changed position (Experiment 3) or were withdrawn from the screen (Experiments 4-­‐5). People showed a strong tendency to gaze at the centre of the screen and only moved towards the head’s former locations if the screen was empty and if evaluation was not preceded by an intervening task as tested in Experiment 5. Fixating the former location resulted in faster response time but not in better accuracy of evaluation. The second part of this thesis investigated the role of spatial location representations in reading (Experiments 6-­‐7). Specifically, I examined to what extent people reading garden-­‐path sentences regress to specific target words in order to reanalyse the sentences. The results of two eye-­‐tracking experiments showed that readers do not target very precisely. A spatial representation is used, but it appears to be fairly coarse (i.e., only represents whether information is to the left or to the right of fixation). The findings from this thesis give us a clearer understanding of the influence of spatial location information on language processing. In language production particularly, it appears that spatial location is an integral part of the cognitive model and strongly connected with linguistic and visual representations.

In this thesis, a system to locate an electrostatic discharge (ESD) event within an electronic device has been developed. ESD can cause a device to fail legally required radiated emissions limits as well as disrupt intended operation. The system used a fast oscilloscope with four channels, each channel attached to a high frequency near-field antenna. These antennas were placed at known locations in three dimensional space to measure the fields radiated from the ESD event. A Time-Difference-of-Arrival technique was used to calculate the location of the ESD event. Quick determination of the ESD event location provides developers with a tool that saves them time and money by eliminating the time-consuming and tedious method of general ESD mitigation within a product.

Thanks to its improved capabilities, the Multiple Input Multiple Output (MIMO) radar is attracting the attention of researchers and practitioners alike. Because it transmits orthogonal or partially correlated waveforms, this emerging technology outperformed the phased array radar by providing better parametric identifiability, achieving higher spatial resolution, and designing complex beampatterns. To avoid jamming and enhance the signal to noise ratio, it is often interesting to maximize the transmitted power in a given region of interest and minimize it elsewhere. This problem is known as the transmit beampattern design and is usually tackled as a two-step process: a transmit covariance matrix is firstly designed by minimizing a convex optimization problem, which is then used to generate practical waveforms. In this work, we propose simple novel methods to generate correlated waveforms using finite alphabet constant and non-constant-envelope symbols. To generate finite alphabet waveforms, the proposed method maps easily generated Gaussian random variables onto the phase-shift-keying, pulse-amplitude, and quadrature-amplitude modulation schemes. For such mapping, the probability density function of Gaussian random variables is divided into M regions, where M is the number of alphabets in the corresponding modulation scheme. By exploiting the mapping function, the relationship between the cross-correlation of Gaussian and finite alphabet symbols is derived. The second part of this thesis covers the topic of target parameter estimation. To determine the reflection coefficient, spatial location, and Doppler shift of a target, maximum likelihood estimation yields the best performance. However, it requires a two dimensional search problem. Therefore, its computational complexity is prohibitively high. So, we proposed a reduced complexity and optimum performance algorithm which allows the two dimensional fast Fourier transform to jointly estimate the spatial location and Doppler shift. To assess the performance of the proposed estimators, the Cramér-Rao Lower Bound (CRLB) is derived. Simulation results show that the mean square estimation error of the proposed estimators achieve the CRLB. Keywords: Collocate antennas, multiple-input multiple-output (MIMO) radar, Finite alphabet waveforms, Hermite polynomials, Reflection coefficient, Doppler, Spatial location, Cramér-Rao Lower Bound.

No description available.

A memória para a ordem dos eventos em uma sequência está relacionada com muitos domínios cognitivos, como direcionar o comportamento a um objetivo, reconhecer uma ação e prever eventos do ambiente. A codificação da ordem serial tem sido, portanto, um tema polêmico a ser explicado pelos modelos de memória de trabalho visuoespacial. Neste estudo investigamos a codificação incidental da ordem serial de eventos em tarefas de reconhecimento de sequências, nas quais a dimensão relevante para a resposta poderia ser a aparência visual, a localização espacial ou a conjunção visuoespacial dos eventos. A tarefa exigia que os participantes (n=60) detectassem uma mudança em um dos estímulos da sequência e ignorassem mudanças na dimensão irrelevante: a ordem na qual os eventos eram apresentados. De maneira geral, o desempenho foi mais prejudicado nas sequências em que a ordem dos itens mudava. A comparação das três condições de memória (aparência visual, localização espacial e conjunção visuoespacial) revelou que houve melhor desempenho na tarefa espacial. Nesta condição, ocorreu uma interação entre os fatores mudança na dimensão relevante (localização espacial) e mudança na dimensão irrelevante (ordem serial). Estes resultados revelam que a ordem foi codificada de forma incidental com as informações relevantes para a tarefa. A diferença do efeito da mudança da dimensão irrelevante para os três tipos de sequências sugere que a ordem foi codificada em um estágio inicial do processamento de informações e, por isto, incluída na comparação de características, gerando diferentes padrões de respostas conforme a modalidade do estímulo. A interação entre localização e ordem serial indica que a informação espacial foi registrada de maneira integrada à ordem dos eventos na sequência, em uma representação espaço-temporal unitária. Supõe-se que um mecanismo de manutenção da informação espacial tenha operado recitando os eventos na ordem em que foram apresentados na sequência. Considera-se, também, a possibilidade de a apresentação sequencial dos estímulos ter gerado uma representação visuoespacial baseada em uma organização temporal das informações. Neste caso, é provável que um mecanismo de integração de informações tenha operado para realizar a interface entre uma estrutura temporal previamente armazenada na memória de longo prazo e o conteúdo da memória de trabalho. Estes achados sugerem a existência de um sistema responsável pela conjunção de informações de diferentes dimensões e integração de conteúdos da memória de trabalho e memória de longo prazo. As evidências obtidas neste estudo têm implicações em diferentes áreas do conhecimento. Na perspectiva da psicologia cognitiva experimental são discutidos os modelos atuais de memória de trabalho. No âmbito da psicologia cognitiva aplicada são fornecidos subsídios teóricos para o desenvolvimento de ferramentas diagnósticas para caracterização de déficits de aprendizagem e lesões neurológicas relacionados com o processamento de sequências de informações visuoespaciais. Além disso, é possível estabelecer uma relação entre os processos de memória e os mecanismos de organização do comportamento em contextos clínicos. / The memory for the events order in a sequence is related to many cognitive domains, such as managing behavior to a goal, to recognize an action and anticipate events in the real world. The encoding of serial order has been a controversial topic to be explained by the models of visuospatial working memory. We investigated the incidental encoding of events serial order in recognition tasks sequences, in which a relevant dimension to the response could be the visual appearance, the spatial location or visuospatial conjunction of events. The task required that participants (n = 60) to detect a change in a sequence of stimuli and ignore changes in irrelevant dimension: the order in which events were presented. In general, performance was more impaired in the sequences where the order of items changed. The comparison of the three memory conditions (visual appearance, spatial location and visuospatial conjunction) revealed that there was better performance in spatial task. In this condition, there was an interaction between change in the relevant dimension (spatial location) and change in the irrelevant dimension (serial order). These results show that the order was codified indirectly with relevant information to the task. The difference in the effect of changing the dimension irrelevant to the three types of sequences suggests that the order was codified in an early stage of information processing and, therefore, included in feature comparison, generating different patterns of responses depending on the modality of the stimulus. The interaction between location and serial order indicates that the spatial information was registered in an integrated manner to the order of events following in a unitary space-time representation. It is assumed that a mechanism for maintenance of spatial information has operated reciting the events in the order they were presented in sequence. It is considered also the possibility that the sequential presentation of stimuli have generated a visuospatial representation based on information temporal organization. In this case, it is likely that a mechanism of information integration has operated to achieve the interface between a temporal structure previously stored in long-term memory and the contents of working memory. These findings suggest the existence of a system responsible for the combination of information from different dimensions and integration of working memory contents and long-term memory. Data obtained in this study have implications in different areas of knowledge. In view of experimental cognitive psychology current models of working memory are discussed. Within the cognitive psychology applied theoretical support are provided for the development of diagnostic tools for characterizing learning deficits and neurological injuries related to the processing of visuospatial information sequences. Furthermore, it is possible to establish a relationship between memory processes and the mechanisms of organization of behavior in clinical settings.

A memória para a ordem dos eventos em uma sequência está relacionada com muitos domínios cognitivos, como direcionar o comportamento a um objetivo, reconhecer uma ação e prever eventos do ambiente. A codificação da ordem serial tem sido, portanto, um tema polêmico a ser explicado pelos modelos de memória de trabalho visuoespacial. Neste estudo investigamos a codificação incidental da ordem serial de eventos em tarefas de reconhecimento de sequências, nas quais a dimensão relevante para a resposta poderia ser a aparência visual, a localização espacial ou a conjunção visuoespacial dos eventos. A tarefa exigia que os participantes (n=60) detectassem uma mudança em um dos estímulos da sequência e ignorassem mudanças na dimensão irrelevante: a ordem na qual os eventos eram apresentados. De maneira geral, o desempenho foi mais prejudicado nas sequências em que a ordem dos itens mudava. A comparação das três condições de memória (aparência visual, localização espacial e conjunção visuoespacial) revelou que houve melhor desempenho na tarefa espacial. Nesta condição, ocorreu uma interação entre os fatores mudança na dimensão relevante (localização espacial) e mudança na dimensão irrelevante (ordem serial). Estes resultados revelam que a ordem foi codificada de forma incidental com as informações relevantes para a tarefa. A diferença do efeito da mudança da dimensão irrelevante para os três tipos de sequências sugere que a ordem foi codificada em um estágio inicial do processamento de informações e, por isto, incluída na comparação de características, gerando diferentes padrões de respostas conforme a modalidade do estímulo. A interação entre localização e ordem serial indica que a informação espacial foi registrada de maneira integrada à ordem dos eventos na sequência, em uma representação espaço-temporal unitária. Supõe-se que um mecanismo de manutenção da informação espacial tenha operado recitando os eventos na ordem em que foram apresentados na sequência. Considera-se, também, a possibilidade de a apresentação sequencial dos estímulos ter gerado uma representação visuoespacial baseada em uma organização temporal das informações. Neste caso, é provável que um mecanismo de integração de informações tenha operado para realizar a interface entre uma estrutura temporal previamente armazenada na memória de longo prazo e o conteúdo da memória de trabalho. Estes achados sugerem a existência de um sistema responsável pela conjunção de informações de diferentes dimensões e integração de conteúdos da memória de trabalho e memória de longo prazo. As evidências obtidas neste estudo têm implicações em diferentes áreas do conhecimento. Na perspectiva da psicologia cognitiva experimental são discutidos os modelos atuais de memória de trabalho. No âmbito da psicologia cognitiva aplicada são fornecidos subsídios teóricos para o desenvolvimento de ferramentas diagnósticas para caracterização de déficits de aprendizagem e lesões neurológicas relacionados com o processamento de sequências de informações visuoespaciais. Além disso, é possível estabelecer uma relação entre os processos de memória e os mecanismos de organização do comportamento em contextos clínicos. / The memory for the events order in a sequence is related to many cognitive domains, such as managing behavior to a goal, to recognize an action and anticipate events in the real world. The encoding of serial order has been a controversial topic to be explained by the models of visuospatial working memory. We investigated the incidental encoding of events serial order in recognition tasks sequences, in which a relevant dimension to the response could be the visual appearance, the spatial location or visuospatial conjunction of events. The task required that participants (n = 60) to detect a change in a sequence of stimuli and ignore changes in irrelevant dimension: the order in which events were presented. In general, performance was more impaired in the sequences where the order of items changed. The comparison of the three memory conditions (visual appearance, spatial location and visuospatial conjunction) revealed that there was better performance in spatial task. In this condition, there was an interaction between change in the relevant dimension (spatial location) and change in the irrelevant dimension (serial order). These results show that the order was codified indirectly with relevant information to the task. The difference in the effect of changing the dimension irrelevant to the three types of sequences suggests that the order was codified in an early stage of information processing and, therefore, included in feature comparison, generating different patterns of responses depending on the modality of the stimulus. The interaction between location and serial order indicates that the spatial information was registered in an integrated manner to the order of events following in a unitary space-time representation. It is assumed that a mechanism for maintenance of spatial information has operated reciting the events in the order they were presented in sequence. It is considered also the possibility that the sequential presentation of stimuli have generated a visuospatial representation based on information temporal organization. In this case, it is likely that a mechanism of information integration has operated to achieve the interface between a temporal structure previously stored in long-term memory and the contents of working memory. These findings suggest the existence of a system responsible for the combination of information from different dimensions and integration of working memory contents and long-term memory. Data obtained in this study have implications in different areas of knowledge. In view of experimental cognitive psychology current models of working memory are discussed. Within the cognitive psychology applied theoretical support are provided for the development of diagnostic tools for characterizing learning deficits and neurological injuries related to the processing of visuospatial information sequences. Furthermore, it is possible to establish a relationship between memory processes and the mechanisms of organization of behavior in clinical settings.

Le but de cette étude était de déterminer la contribution de plusieurs facteurs (le design de la tâche, l’orientation d’angle, la position de la tête et du regard) sur la capacité des sujets à percevoir les différences de formes bidimensionnelles (2-D) en utilisant le toucher haptique. Deux séries d'expériences (n = 12 chacune) ont été effectuées. Dans tous les cas, les angles ont été explorés avec l'index du bras tendu. La première expérience a démontré que le seuil de discrimination des angles 2-D a été nettement plus élevé, 7,4°, que le seuil de catégorisation des angles 2-D, 3,9°. Ce résultat étend les travaux précédents, en montrant que la différence est présente dans les mêmes sujets testés dans des conditions identiques (connaissance des résultats, conditions d'essai visuel, l’orientation d’angle). Les résultats ont également montré que l'angle de catégorisation ne varie pas en fonction de l'orientation des angles dans l'espace (oblique, verticale). Étant donné que les angles présentés étaient tous distribués autour de 90°, ce qui peut être un cas particulier comme dans la vision, cette constatation doit être étendue à différentes gammes d'angles. Le seuil plus élevé dans la tâche de discrimination reflète probablement une exigence cognitive accrue de cette tâche en demandant aux sujets de mémoriser temporairement une représentation mentale du premier angle exploré et de la comparer avec le deuxième angle exploré. La deuxième expérience représente la suite logique d’une expérience antérieure dans laquelle on a constaté que le seuil de catégorisation est modifié avec la direction du regard, mais pas avec la position de la tête quand les angles (non visibles) sont explorés en position excentrique, 60° à la droite de la ligne médiane. Cette expérience a testé l'hypothèse que l'augmentation du seuil, quand le regard est dirigé vers l'extrême droite, pourrait refléter une action de l'attention spatiale. Les sujets ont exploré les angles situés à droite de la ligne médiane, variant systématiquement la direction du regard (loin ou vers l’angle) de même que l'emplacement d'angle (30° et 60° vers la droite). Les seuils de catégorisation n’ont démontré aucun changement parmi les conditions testées, bien que le biais (point d'égalité subjective) ait été modifié (décalage aux valeurs inférieurs à 90°). Puisque notre test avec le regard fixé à l’extrême droite (loin) n'a eu aucun effet sur le seuil, nous proposons que le facteur clé contribuant à l'augmentation du seuil vu précédemment (tête tout droit/regard à droite) doit être cette combinaison particulière de la tête/regard/angles et non l’attention spatiale. / The purpose was to determine the contribution of several factors (design of the task, angle orientation, head position and gaze) to the ability of subjects to perceive differences in twodimensional (2-D) shape using haptic touch. Two series of experiments (n=12 each) were carried out. In all cases the angles were explored with the index finger of the outstretched arm. The first experiment showed that the mean threshold for 2-D angle discrimination was significantly higher, 7.4°, than for 2-D angle categorization, 3.9°. This result extended previous work, by showing that the difference is present in the same subjects tested under identical conditions (knowledge of results, visual test conditions, angle orientation). The results also showed that angle categorization did not vary as a function of the orientation of the angles in space (oblique, upright). Given that the angles presented were all distributed around 90°, and that this may be a special case as in vision, this finding needs to be extended to different ranges of angles. The higher threshold with angle discrimination likely reflects the increased cognitive demands of this task which required subjects to temporarily store a mental representation of the first angle scanned, and to compare this to the second scanned angle. The second experiment followed up on observations that categorization thresholds are modified with gaze direction but not head position when the unseen angles are explored in an eccentric position, 60° to the right of midline. This experiment tested the hypothesis that the increased threshold when gaze was directed to the far right might reflect an action of spatial attention. Subjects explored angles located to the right of midline, systematically varying the direction of gaze (away from or to the angles) along with angle location (30° and 60° to the right). Categorization thresholds showed no change across the conditions tested, although bias (point of subjective equality) was changed (shift to lower angle values). Since our testing with far right gaze (away) had no effect on threshold, we suggest that the key factor contributing to the increased threshold seen previously (head forward/gaze right) must have been this particular combination of head/gaze/angles used and not spatial attention.

A livre atuação do mercado imobiliário estratifica o espaço urbano de acordo com as características socioeconômicas de seus habitantes. Essa estratificação social, na sua representação espacial, restringe as possibilidades locacionais de moradia das populações de baixa renda, o que gera dificuldades de localização em áreas com amplo acesso a equipamentos, comércio e serviços. Se o funcionamento do mercado cria tais restrições, cabe ao Estado regular esse funcionamento, organizando a distribuição espacial das populações. Esse trabalho analisa a atual política pública de provisão de moradias, a Política Nacional de Habitação, com foco na localização das habitações produzidas para a população de baixa renda, através do Programa Minha Casa Minha Vida, com estudo de caso no município de Porto Alegre. O estudo é desenvolvido em três etapas: iniciou-se pela análise comparativa dos objetivos da Política e do Programa com base nas normativas legais e de suas publicações oficiais, em relação aos conceitos para avaliação de políticas públicas apresentados por Sartori (1981), Clapham (2005) e Alvim e Castro (2010). Em seguida, desenvolveu-se o estudo de casos dos empreendimentos do Programa, edificados no município de Porto Alegre, analisando as suas localizações em relação a equipamentos, comércio, serviços e rede de transportes, de acordo com a metodologia desenvolvida pelo LabCidade et. al. (2014), cuja avaliação baseou-se nos critérios de localização conceituados segundo Cardoso (2001) e Villaça (1998). E por fim, analisouse os resultados das etapas anteriores, vinculando as localizações produzidas a formulação do Programa e da Política. / The free acting of the real estate market stratifies the urban space according to the inhabitants socioeconomic characteristics. This social stratification, in its spatial representation, restricts the locational possibilities of housing for the low income populations, which generates difficulties of location in urban areas with wide access to equipments, commerce and services. If the functioning of the market creates such restrictions, it is up to the State to regulate this functioning by organizing the spatial distribution of its population. This study analyzes the current public housing policy, the National Housing Policy, focused on the location of housing produced for the low income population through the Minha Casa Minha Vida Program, with a study case in the city of Porto Alegre. The study is developed in three stages: it began with the comparative analysis of the objectives of the Policy and the Program based on legal norms and its official publications, in relation to the concepts for evaluation of public policies presented by Sartori (1981), Clapham (2005) and Alvim and Castro (2010). Next, the study case of the projects developed in the city of Porto Alegre was created, analyzing their locations in relation to equipment, commerce, services and mobility network, according to the methodology developed by LabCidade et. al. (2014), whose evaluation was based on the location criteria according to Cardoso (2001) and Villaça (1998). And finally, the results of the previous stages linking the locations to the Program and Policy formulation.

Le but de cette étude était de déterminer la contribution de plusieurs facteurs (le design de la tâche, l’orientation d’angle, la position de la tête et du regard) sur la capacité des sujets à percevoir les différences de formes bidimensionnelles (2-D) en utilisant le toucher haptique. Deux séries d'expériences (n = 12 chacune) ont été effectuées. Dans tous les cas, les angles ont été explorés avec l'index du bras tendu. La première expérience a démontré que le seuil de discrimination des angles 2-D a été nettement plus élevé, 7,4°, que le seuil de catégorisation des angles 2-D, 3,9°. Ce résultat étend les travaux précédents, en montrant que la différence est présente dans les mêmes sujets testés dans des conditions identiques (connaissance des résultats, conditions d'essai visuel, l’orientation d’angle). Les résultats ont également montré que l'angle de catégorisation ne varie pas en fonction de l'orientation des angles dans l'espace (oblique, verticale). Étant donné que les angles présentés étaient tous distribués autour de 90°, ce qui peut être un cas particulier comme dans la vision, cette constatation doit être étendue à différentes gammes d'angles. Le seuil plus élevé dans la tâche de discrimination reflète probablement une exigence cognitive accrue de cette tâche en demandant aux sujets de mémoriser temporairement une représentation mentale du premier angle exploré et de la comparer avec le deuxième angle exploré. La deuxième expérience représente la suite logique d’une expérience antérieure dans laquelle on a constaté que le seuil de catégorisation est modifié avec la direction du regard, mais pas avec la position de la tête quand les angles (non visibles) sont explorés en position excentrique, 60° à la droite de la ligne médiane. Cette expérience a testé l'hypothèse que l'augmentation du seuil, quand le regard est dirigé vers l'extrême droite, pourrait refléter une action de l'attention spatiale. Les sujets ont exploré les angles situés à droite de la ligne médiane, variant systématiquement la direction du regard (loin ou vers l’angle) de même que l'emplacement d'angle (30° et 60° vers la droite). Les seuils de catégorisation n’ont démontré aucun changement parmi les conditions testées, bien que le biais (point d'égalité subjective) ait été modifié (décalage aux valeurs inférieurs à 90°). Puisque notre test avec le regard fixé à l’extrême droite (loin) n'a eu aucun effet sur le seuil, nous proposons que le facteur clé contribuant à l'augmentation du seuil vu précédemment (tête tout droit/regard à droite) doit être cette combinaison particulière de la tête/regard/angles et non l’attention spatiale. / The purpose was to determine the contribution of several factors (design of the task, angle orientation, head position and gaze) to the ability of subjects to perceive differences in twodimensional (2-D) shape using haptic touch. Two series of experiments (n=12 each) were carried out. In all cases the angles were explored with the index finger of the outstretched arm. The first experiment showed that the mean threshold for 2-D angle discrimination was significantly higher, 7.4°, than for 2-D angle categorization, 3.9°. This result extended previous work, by showing that the difference is present in the same subjects tested under identical conditions (knowledge of results, visual test conditions, angle orientation). The results also showed that angle categorization did not vary as a function of the orientation of the angles in space (oblique, upright). Given that the angles presented were all distributed around 90°, and that this may be a special case as in vision, this finding needs to be extended to different ranges of angles. The higher threshold with angle discrimination likely reflects the increased cognitive demands of this task which required subjects to temporarily store a mental representation of the first angle scanned, and to compare this to the second scanned angle. The second experiment followed up on observations that categorization thresholds are modified with gaze direction but not head position when the unseen angles are explored in an eccentric position, 60° to the right of midline. This experiment tested the hypothesis that the increased threshold when gaze was directed to the far right might reflect an action of spatial attention. Subjects explored angles located to the right of midline, systematically varying the direction of gaze (away from or to the angles) along with angle location (30° and 60° to the right). Categorization thresholds showed no change across the conditions tested, although bias (point of subjective equality) was changed (shift to lower angle values). Since our testing with far right gaze (away) had no effect on threshold, we suggest that the key factor contributing to the increased threshold seen previously (head forward/gaze right) must have been this particular combination of head/gaze/angles used and not spatial attention.

Au cours des soixante dernières années, la population mondiale a connu un sursaut spectaculaire, passant de 2,5 milliards d’habitants à la fin de la Seconde Guerre mondiale à 7 milliards en 2011. Cette croissance démographique se distingue des précédents épisodes tant par son importance que par l'apparition conjointe d'une tendance nouvelle et soutenue à la concentration des populations au sein des villes. Appelée à se renforcer partout dans le monde, cette tendance au grossissement des villes lance un véritable défi à la communauté internationale en matière de durabilité de notre système économique en général et alimentaire en particulier. Cette thèse propose un traitement théorique de la question de la durabilité des systèmes d'approvisionnement alimentaires en milieu urbain. A la frontière entre économie publique et économie géographique, elle poursuit comme objectif principal de permettre la conduite d'une analyse formalisée des arbitrages environnementaux et sociaux dans un cadre spatial explicite. En outre, l'idée selon laquelle aucune réponse ne saurait être satisfaisante sans qu'une attention spécifique soit portée aux interactions spatiales, économiques et écologiques entre espaces urbains et agriculture constitue l'un des positionnements clés défendus dans ce travail. De manière générale, les travaux de cette thèse font apparaître l'élément majeur suivant: du fait de la forte et inextricable interconnexion entre milieux urbain et rural, l'évaluation environnementale, sociale et économique d'un système alimentaire ne peut se faire qu'en connaissance des caractéristiques démographique et physique de la ville concernée. / Over the past sixty years, the world population has experienced a dramatic surge from 2.5 billion people by the end of World War II, to 7 billion in 2011. This population growth differs from previous episodes not only in importance, but also because of the joint emergence of a new and ongoing trend of rising urbanization. Expected to strengthen worldwide, this trend is a real challenge for the international community in terms of sustainability, especially for food supply. This thesis provides a theoretical treatment of food supply chain sustainability in a context of rapid and unrelenting urbanization. Halfway between economic geography and environmental economics, its primary goal is to allow for a theoretical formalization of ecological and social trade-offs in a spatially explicit framework. Besides, we argue that this issue cannot satisfactorily resolved without paying specific attention to urban-rural interactions. Our work discloses the following major element : because of the tight and inextricable interconnection between urban and rural areas, the ecological assessment of any food supply chain can only be achieved by taking into account both the demographic and physical features of cities.