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Garcelon, Evrard. "Constrained Exploration in Reinforcement Learning". Electronic Thesis or Diss., Institut polytechnique de Paris, 2022. http://www.theses.fr/2022IPPAG007.
Pełny tekst źródłaA major application of machine learning is to provide personnalized content to different users. In general, the algorithms powering those recommandation are supervised learning algorithm. That is to say the data used to train those algorithms are assumed to be sampled from the same distribution. However, the data are generated through interactions between the users and the recommendation algorithms. Thus, recommendations for a user a time t can have an impact on the set of pertinent recommandation at a later time. Therefore, it is necessary to take those interactions into account. This setting is reminiscent of the online learning setting. Among online learning algorithms, Reinforcement Learning algorithms (RL) looks the most promising to replace supervised learning algorithms for applications requiring a certain degree of personnalization. The deployement in production of RL algorithms presents some challenges such as being able to guarantee a certain level of performance during exploration phases or how to guarantee privacy of the data collected by RL algorithms. In this thesis, we consider different constraints limiting the use of RL algorithms and provides both empirical and theoretical results on the impact of those constraints on the learning process
Carvalho, Filho José Gilmar Nunes de. "Multi-robot exploration with constrained communication". reponame:Repositório Institucional da UFSC, 2016. https://repositorio.ufsc.br/xmlui/handle/123456789/171998.
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Abstract : Over the last two decades, several methods for exploration with Multi-Robot Systems (MRS) have been proposed, most of them based on the allocation of frontiers (exploration targets) and typically applying local optimization policies. However, communication issues have usually been neglected. This thesis investigates multi-robot exploration by considering that robots have limited communication radius. Two methods, one based on a flat network architecture (DSM) and another based on a hierarchical architecture (HSM), were proposed to share map information. While DSM considers a propagation scheme to share information and synchronize the map of robots, HSM organizes robots in a hierarchical architecture where some robots act as leaders (clusterheads) and are responsible for synchronizing the maps of the robots in the network. Formal proof that both methods guarantee the synchronization of the map of all robots in a network is presented. In addition, experiments were conducted by considering systems with different number of robots, network topologies and different map's sizes. The results show that both methods are able to synchronize the map of the robots when they can lose communication links, but HKM usually presents smaller convergence time, number of exchanged messages and amount of transmitted data. We also propose Hierarchical K-Means (HKME), a method for multi-robot coordination in exploration tasks that handles communication problems, such as link losses. To handle communication among robots, HKME arranges them into clusters and elects leaders for each. Clusters evolve dynamically as robots lose or establish communication with their peers. HKME uses HSM to guarantee that the map of the robots are synchronized and also uses the hierarchical organization of the robots to coordinate them in order to minimize the variance of the time at which they reach all regions of the workspace, while balancing their workload and decreasing the exploration time. Experiments were conducted by considering different types of workspace and communication radius. The results show that HKME behaves like a centralized algorithm when communication is granted, while being able to withstand severe degradation in communication radius.
Ao longo das últimas décadas, vários métodos de exploração com os Sistemas Multi-robôs (SMR) têm sido propostos, a maioria deles com base na alocação de fronteiras (alvos de exploração) e normalmente aplicando políticas de otimização locais. No entanto, os problemas de comunicação têm geralmente sido negligenciados. Esta tese investiga a exploração multi-robô, considerando que os robôs têm raio de comunicação limitado. Dois métodos, um baseado em uma arquitetura de rede plana (DSM) e outro baseado em uma arquitetura hierárquica (HSM), foram propostos para compartilhar informações de mapa. Enquanto o DSM considera um esquema de propagação para compartilhar informações e sincronizar o mapa dos robôs, o HSM organiza robôs em uma arquitetura hierárquica, onde alguns robôs atuam como líderes (clusterheads) e são responsáveis por sincronizar os mapas dos robôs na rede. A prova formal de que ambos os métodos garantem a sincronização do mapa de todos os robôs na rede é apresentada. Além disso, experimentos foram conduzidos considerando sistemas com diferentes números de robôs, topologias de rede e tamanhos de mapa. Os resultados mostram que ambos os métodos são capazes de sincronizar o mapa dos robôs quando eles podem perder links de comunicação, mas o HKM geralmente apresenta menor tempo de convergência, o número de mensagens trocadas e a quantidade de dados transmitidos. Propomos também Hierarchical K-Means (HKME), um método de coordenação multi-robô em tarefas de exploração que lida com problemas de comunicação, tais como perdas de links. Para lidar com a comunicação entre robôs, o HKME os organiza em clusters e elege os líderes de cada um. Clusters evoluem dinamicamente a medida que os robôs perdem ou estabelecem links de comunicação. O HKME usa o HSM para garantir que o mapa dos robôs se mantenham sincronizados e também usa a organização hierárquica dos robôs para coordená-los, a fim de minimizar a variância do momento em que eles atinjem todas as regiões do espaço de trabalho, ao mesmo tempo que equilibra a carga de trabalho e diminui o tempo de exploração. Experimentos foram realizadas considerando diferentes tipos de espaço de trabalho e raios de comunicação. Os resultados mostram que o HKME comporta-se como um algoritmo centralizada quando a comunicação é garantida, sendo capaz de lidar com uma degradação severa no raio de comunicação.
Duong, Khanh-Chuong. "Constrained clustering by constraint programming". Thesis, Orléans, 2014. http://www.theses.fr/2014ORLE2049/document.
Pełny tekst źródłaCluster analysis is an important task in Data Mining with hundreds of different approaches in the literature. Since the last decade, the cluster analysis has been extended to constrained clustering, also called semi-supervised clustering, so as to integrate previous knowledge on data to clustering algorithms. In this dissertation, we explore Constraint Programming (CP) for solving the task of constrained clustering. The main principles in CP are: (1) users specify declaratively the problem in a Constraint Satisfaction Problem; (2) solvers search for solutions by constraint propagation and search. Relying on CP has two main advantages: the declarativity, which enables to easily add new constraints and the ability to find an optimal solution satisfying all the constraints (when there exists one). We propose two models based on CP to address constrained clustering tasks. The models are flexible and general and supports instance-level constraints and different cluster-level constraints. It also allows the users to choose among different optimization criteria. In order to improve the efficiency, different aspects have been studied in the dissertation. Experiments on various classical datasets show that our models are competitive with other exact approaches. We show that our models can easily be embedded in a more general process and we illustrate this on the problem of finding the Pareto front of a bi-criterion optimization process
Kettler, Daniel Terrance. "Mechanical design for the tactile exploration of constrained internal geometries". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/50272.
Pełny tekst źródłaThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
MIT Institute Archives copy: with CD-ROM; divisional library copy with no CD-ROM.
Includes bibliographical references (p. 93-98).
Rising world oil prices and advanced oil recovery techniques have made it economically attractive to rehabilitate abandoned oil wells. This requires guiding tools through well junctions where divergent branches leave the main wellbore. The unknown locations and shapes of these junctions must be determined. Harsh down-well conditions prevent the use of ranged sensors. However, robotic tactile exploration using a manipulator is well suited to this problem. This tactile characterization must be done quickly because of the high costs of working on oil wells. Consequently, intelligent tactile exploration algorithms that can characterize a shape using sparse data sets must be developed. This thesis explores the design and system architecture of robotic manipulators for down-well tactile exploration. A design approach minimizing sensing is adopted to produce a system that is mechanically robust and suited to the harsh down-well environment. A feasibility study on down-well tactile exploration manipulators is conducted. This study focuses on the mature robotic technology of link and joint manipulators with zero or low kinematic redundancy. This study produces a field system architecture that specifies a unified combination of control, sensing, kinematic solutions for down-well applications. An experimental system is built to demonstrate the proposed field system architecture and test control and intelligent tactile exploration algorithms. Experimental results to date have indicated acceptability of the proposed field system architecture and have demonstrated the ability to characterize geometry with sparse tactile data.
(cont.) Serpentine manipulators implemented using digital mechatronic actuation are also considered. Digital mechatronic devices use actuators with discrete output states and the potential to be mechanically robust and inexpensive. The design of digital mechatronic devices is challenging. Design parameter optimization methods are developed and applied to a design case study of a manipulator in a constrained workspace. This research demonstrates that down-well tactile exploration with a manipulator is feasible. Experimental results show that the proposed field system architecture, a 4 degree-of-freedom anthropomorphic manipulator, can obtain accurate tactile data without using any sensor feedback besides manipulator joint angles.
by Daniel Terrance Kettler.
S.M.
Chung, Jen Jen. "Learning to soar: exploration strategies in reinforcement learning for resource-constrained missions". Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/11733.
Pełny tekst źródłaSun, Hua. "Throughput constrained and area optimized dataflow synthesis for FPGAS". Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2276.pdf.
Pełny tekst źródłaBhattacharjee, Protim [Verfasser], Veniamin [Akademischer Betreuer] Morgenshtern i Martin [Gutachter] Burger. "Compressed Sensing based Image Acquisition Methodologies for Constrained Autonomous Exploration Systems with Single Pixel Cameras / Protim Bhattacharjee ; Gutachter: Martin Burger ; Betreuer: Veniamin Morgenshtern". Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2021. http://d-nb.info/123348429X/34.
Pełny tekst źródłaWilliams, Nicholas Cory. "Geologically-constrained UBC–GIF gravity and magnetic inversions with examples from the Agnew-Wiluna greenstone belt, Western Australia". Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2744.
Pełny tekst źródłaClifford, Gayle. ""Am iz kwiin" (I'm his queen) : an exploration of mothers' disclosure of maternal HIV to their children in Kingston, Jamaica : using feminist Interpretative Phenomenological Analysis (IPA) in a resource-constrained context". Thesis, City, University of London, 2018. http://openaccess.city.ac.uk/21213/.
Pełny tekst źródłaCraparo, Emily M. (Emily Marie) 1980. "Cooperative exploration under communication constraints". Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/46558.
Pełny tekst źródłaIncludes bibliographical references (leaves 131-137).
The cooperative exploration problem necessarily involves communication among agents, while the spatial separation inherent in this task places fundamental limits on the amount of data that can be transmitted. However, the impact of limited communication on the exploration process has not been fully characterized. Existing exploration algorithms do not realistically model the tradeoff between expansion, which allows more rapid exploration of the area of interest, and maintenance of close relative proximity among agents, which facilitates communication. This thesis develops new algorithms applicable to the problem of cooperative exploration under communication constraints. The exploration problem is decomposed into two parts. In the first part, cooperative exploration is considered in the context of a hierarchical communication framework known as a mobile backbone network. In such a network, mobile backbone nodes, which have good mobility and communication capabilities, provide communication support for regular nodes, which are constrained in movement and communication capabilities but which can sense the environment. New exact and approximation algorithms are developed for throughput optimization in networks composed of stationary regular nodes, and new extensions are formulated to take advantage of regular node mobility. These algorithms are then applied to a cooperative coverage problem. In the second part of this work, techniques are developed for utilizing a given level of throughput in the context of cooperative estimation. The mathematical properties of the information form of the Kalman filter are leveraged in the development of two algorithms for selecting highly informative portions of the information matrix for transmission. One algorithm, a fully polynomial time approximation scheme, provides provably good results in computationally tractable time for problem instances of a particular structure. The other, a heuristic method applicable to instances of arbitrary matrix structure, performs very well in simulation for randomly-generated problems of realistic dimension.
by Emily M. Craparo.
Ph.D.
Kilian, Axel 1971. "Design exploration through bidirectional modeling of constraints". Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/33803.
Pełny tekst źródłaThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 315-324).
Today digital models for design exploration are not used to their full potential. The research efforts in the past decades have placed geometric design representations firmly at the center of digital design environments. In this thesis it is argued that models for design exploration that bridge different representation aid in the discovery of novel designs. Replacing commonly used analytical, uni-directional models for linking representations, with bidirectional ones, further supports design exploration. The key benefit of bidirectional models is the ability to swap the role of driver and driven in the exploration. The thesis developed around a set of design experiments that tested the integration of bidirectional computational models in domain specific designs. From the experiments three main exploration types emerged. They are: branching explorations for establishing constraints for an undefined design problem; illustrated in the design of a concept car. Circular explorations for the refinement of constraint relationships; illustrated in the design of a chair. Parallel explorations for exercising well-understood constraints; illustrated in a form finding model in architecture. A key contribution of the thesis is the novel use of constraint diagrams developed to construct design explorers for the experiments. The diagrams show the importance of translations between design representations in establishing design drivers from the set of constraints. The incomplete mapping of design features across different representations requires the redescription of the design for each translation.
(cont.) This redescription is a key aspect of exploration and supports design innovation. Finally, this thesis argues that the development of design specific design explorers favors a shift in software design away from monolithic, integrated software environments and towards open software platforms that support user development.
by Axel Kilian.
Ph.D.
Cerf, Loïc. "Constraint-based mining of closed patterns in noisy n-ary relations". Lyon, INSA, 2010. http://theses.insa-lyon.fr/publication/2010ISAL0050/these.pdf.
Pełny tekst źródłaLes processus de découverte de connaissances nouvelles peuvent être fondés sur des motifs locaux extraits de grands jeux de données. Concevoir des algorithmes de fouille de données efficaces pour calculer des collections de motifs pertinents est un domaine actif de recherche. Beaucoup de jeux de données enregistrent si des objets présentent ou non certaines propriétés; par exemple si un produit est acheté par un client ou si un gène est sur exprimé dans un échantillon biologique. Ces jeux de données sont des relations binaires et peuvent être représentés par des matrices 0/1. Dans de telles matrices, un ensemble fermé est un rectangle maximal de '1's modulo des permutations arbitraires des lignes (objets) et des colonnes (propriétés). Ainsi, chaque ensemble fermé sous tend la découverte d'un sous ensemble maximal d'objets partageant le même sous ensemble maximal de propriétés. L'extraction efficace de tous les ensembles fermés, satisfaisant des contraintes de pertinences définies par l'utilisateur, a été étudiée en profondeur. Malgré son succès dans de nombreux domaines applicatifs, ce cadre de travail se révèle souvent trop étroit. Tout d'abord, beaucoup de jeux de données sont des relations n-aires, c'est à dire des tenseurs 0/1. Réduire leur analyse à deux dimensions revient à ignorer des dimensions additionnelles potentiellement intéressantes; par exemple où un client achète un produit (analyse spatiale) ou quand l'expression d'un gène est mesurée (analyse cinétique). La présence de bruit dans la plupart des jeux de données réelles est un second problème qui conduit à la fragmentation des motifs à découvrir. On généralise facilement la définition d'un ensemble fermé pour la rendre applicable à des relations de plus grande arité et tolérante au bruit (hyper rectangle maximal avec une borne supérieure de '0's tolérés par hyperplan). Au contraire, généraliser leur extraction est très difficile. En effet, les algorithmes classiques exploitent une propriété mathématique (la connexion de Galois) des ensembles fermés qu'aucune des deux généralisations ne préserve. C'est pourquoi notre extracteur parcourt l'espace des motifs candidats d'une façon originale qui ne favorise aucune dimension. Cette recherche peut être guidée par une très grande classe de contraintes de pertinence que les motifs doivent satisfaire. En particulier, cette thèse étudie des contraintes spécifiquement conçues pour la fouille de quasi cliques presque persistantes dans des graphes dynamiques. Notre extracteur est plusieurs ordres de grandeurs plus efficaces que les algorithmes existants se restreignant à la fouille de motifs exacts dans des relations ternaires ou à la fouille de motifs tolérants aux erreurs dans des relations binaires. Malgré ces résultats, une telle approche exhaustive ne peut souvent pas, en un temps raisonnable, tolérer tout le bruit contenu dans le jeu de données. Dans ce cas, compléter l'extraction avec une agglomération hiérarchique des motifs (qui ne tolèrent pas suffisamment de bruit) améliore la qualité des collections de motifs renvoyées
Mitas̃iūnaite, Ieva. "Mining string data under similarity and soft-frequency constraints : application to promoter sequence analysis". Lyon, INSA, 2009. http://theses.insa-lyon.fr/publication/2009ISAL0036/these.pdf.
Pełny tekst źródłaAn inductive database is a database that contains not only data but also patterns. Inductive databases are designed to support the KDD process. Recent advances in inductive databases research have given rise to a generic solvers capable of solving inductive queries that are arbitrary Boolean combinations of anti-monotonic and monotonic constraints. They are designed to mine different types of pattern (i. E. , patterns from different pattern languages). An instance of such a generic solver exists that is capable of mining string patterns from string data sets. In our main application, promoter sequence analysis, there is a requirement to handle fault-tolerance, as the data intrinsically contains errors, and the phenomenon we are trying to capture is fundamentally degenerate. Our research contribution to fault-tolerant pattern extraction in string data sets is the use of a generic solver, based on a non-trivial formalisation of fault-tolerant pattern extraction as a constraint-based mining task. We identified the stages in the process of the extraction of such patterns where state-of-art strategies can be applied to prune the search space. We then developed a fault-tolerant pattern match function InsDels that generic constraint solving strategies can soundly tackle. We also focused on making local patterns actionable. The bottleneck of most local pattern extraction methods is the burden of spurious patterns. As the analysis of patterns by the application domain experts is time consuming, we cannot afford to present patterns without any objective clue about their relevancy. Therefore we have developed two methods of computing the expected number of patterns extracted in random data sets. If the number of extracted patterns is strongly different from the expected number from random data sets, one can then state that the results exhibits local associations that are a priori relevant because they are unexpected. Among others applications, we have applied our approach to support the discovery of new motifs in gene promoter sequences with promising results
Chahdi, Hatim. "Apports des ontologies à l'analyse exploratoire des images satellitaires". Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTS014/document.
Pełny tekst źródłaSatellite images have become a valuable source of information for Earth observation. They are used to address and analyze multiple environmental issues such as landscapes characterization, urban planning or biodiversity conservation to cite a few.Despite of the large number of existing knowledge extraction techniques, the complexity of satellite images, their large volume, and the specific needs of each community of practice, give rise to new challenges and require the development of highly efficient approaches.In this thesis, we investigate the potential of intelligent combination of knowledge representation systems with statistical learning. Our goal is to develop novel methods which allow automatic analysis of remote sensing images. We elaborate, in this context, two new approaches that consider the images as unlabeled quantitative data and examine the possible use of the available domain knowledge.Our first contribution is a hybrid approach, that successfully combines ontology-based reasoning and semi-supervised clustering for semantic classification. An inference engine first reasons over the available domain knowledge in order to obtain semantically labeled instances. These instances are then used to generate constraints that will guide and enhance the clustering. In this way, our method allows the improvement of the labeling of existing classes while discovering new ones.Our second contribution focuses on scaling ontology reasoning over large datasets. We propose a two step approach where topological clustering is first applied in order to summarize the data, in term of a set of prototypes, and reduces by this way the number of future instances to be treated by the reasoner. The representative prototypes are then labeled using the ontology and the labels automatically propagated to all the input data.We applied our methods to the real-word problem of satellite images classification and interpretation and the obtained results are very promising. They showed, on the one hand, that the quality of the classification can be improved by automatic knowledge integration and that the involvement of experts can be reduced. On the other hand, the upstream exploitation of topographic clustering avoids the calculation of the inferences on all the pixels of the image
Spirin, Victor. "Multi-agent exploration of indoor environments under limited communication constraints". Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:b337a9a7-91c7-451c-b32f-b1cd05ef983d.
Pełny tekst źródłaMcIver, Donald A. "Epithermal precious metal deposits physicochemical constraints, classification characteristics and exploration guidelines". Thesis, Rhodes University, 1997. http://hdl.handle.net/10962/d1005553.
Pełny tekst źródłaAcevedo, Valle Juan Manuel. "Sensorimotor exploration: constraint awareness and social reinforcement in early vocal development". Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/667500.
Pełny tekst źródłaLa motivación principal de este trabajo es la magnitud que las contribuciones al conocimiento en relación al desarrollo infantil pueden aportar a diferentes campos de la ciencia. Particularmente, este trabajo se enfoca en el estudio de los comportamientos de autoexploración sensorimotora en un marco robótico e inspirado en el campo de la psicología del desarrollo. Nuestro objetivo principal es entender el papel que juegan las restricciones motoras y los reflejos imitativos durante la exploración espontánea observada en infantes. Así mismo, este trabajo hace especial énfasis en el desarrollo vocal-auditivo en infantes, que les provee con las herramientas que les permitirán producir sus primeras palabras. Trabajos anteriores han demostrado que los comportamientos de autoexploración sensorimotora en niños, la cual ocurre en gran medida por motivaciones intrínsecas, es un elemento importante para aprender a controlar su cuerpo con tal de alcanzar estados sensoriales específicos. Además, evidencia obtenida de estudios biológicos sugiere tajantemente que la adquisición de conocimiento es regulada por el ambiente en el cual un agente cognitivo se desenvuelve y por el cuerpo del agente per se. Incluso, los procesos de desarrollo que ocurren a nivel físico, cognitivo y social también regulan que es aprendido y cuando esto es aprendido. La primera parte de este trabajo provee al lector con la evidencia teórica y práctica que demuestran la relevancia de esta investigación. Recorriendo conceptos que van desde las ciencias cognitivas y del desarrollo, llegamos a la conclusión de que el lenguaje, y por tanto el habla, deben ser estudiados como fenómenos cognitivos que requieren un cuerpo físico y además un ambiente propicio para su existencia. En la actualidad los sistemas robóticos, reales y simulados, pueden ser considerados como elementos para el estudio de los fenómenos cognitivos naturales. En este trabajo consideramos un ejemplo simple para probar las arquitecturas cognitivas que proponemos, y posteriormente utilizamos dichas arquitecturas con un sintetizador de voz similar al mecanismo humano de producción del habla. Como primera contribución de este trabajo proponemos introducir un mecanismo para construir robots capaces de considerar sus propias restricciones motoras durante la etapa de autoexploración sensorimotora. Ciertos mecanismos de motivación intrínseca para exploración sensorimotora han sido estudiados como posibles conductores de las trayectorias de desarrollo observadas durante el desarrollo temprano del habla. Sin embargo, en previos estudios no se consideró o que este desarrollo está a delimitado por restricciones debido al ambiente, al cuerpo físico, y a las capacidades sensoriales, motoras y cognitivas. En nuestra arquitectura, asumimos que un agente artificial no cuenta con conocimiento de sus limitantes motoras, y por tanto debe descubrirlas durante la etapa de autoexploración. Para tal efecto, el agente es proveído de un sistema somatosensorial que le indica cuando una configuración motora viola las restricciones impuestas por el propio cuerpo. Finalmente, como segunda parte de nuestra contribución proponemos incluir un mecanismo para reforzar el aprendizaje durante la autoexploración. Estudios anteriores demostraron que el ambiente lingüístico en que se desarrolla un infante, o un agente artificial, condiciona sus producciones vocales durante la autoexploración o balbuceo. En este trabajo nos enfocamos en el estudio de episodios de imitación que ocurren durante el desarrollo temprano de un agente. Basados en estudios sobre la interacción entre madres e hijos durante la etapa pre lingüística, proponemos un mecanismo para reforzar el aprendizaje durante la autoexploración con unidades sensoriales relevantes. Entonces, a partir de la arquitectura con autoconocimiento de restricciones motores, construimos una arquitectura que incluye un instructor experto en control sensorimotor. Las interacciones entre el aprendiz y el experto ocurren cuando el aprendiz produce una unidad sensorial relevante para la comunicación durante la autoexploración. En este caso, el experto percibe esta similitud y responde reformulando la producción del aprendiz como la unidad relevante. Cuando el aprendiz percibe una acción del experto, inmediatamente intenta imitarlo. Los resultados presentados en este trabajo sugieren que, los sistemas somatosensoriales, y el reforzamiento social contribuyen a lograr mejores resultados durante la etapa de autoexploración sensorimotora motivada intrínsecamente. En este sentido, se logra una exploración menos redundante, los errores de exploración y evaluación disminuyen, y por último se obtiene una imagen más nítida de las transiciones entre etapas del desarrollo.
La motivació principal d'aquest treball és la magnitud que les contribucions al coneixement en relació al desenvolupament infantil poden aportar a diferents camps de la ciència. Particularment, aquest treball s'enfoca en l'estudi dels comportaments d’autoexploració sensorimotora en un marc robòtic i inspirat en el camp de la psicologia del desenvolupament. El nostre objectiu principal és entendre el paper que juguen les restriccions motores i els reflexos imitatius durant l’exploració espontània observada en infants. Així mateix, aquest treball fa especial èmfasi en el desenvolupament vocal-auditiu en infants, que els proveeix amb les eines que els permetran produir les seves primeres paraules. Treballs anteriors han demostrat que els comportaments d'autoexploració sensorimotora en nens, la qual ocorre en gran mesura per motivacions intrínseques, és un element important per aprendre a controlar el seu cos per tal d'assolir estats sensorials específics. A més, evidencies obtingudes d'estudis biològics suggereixen que l’adquisició de coneixement és regulada per l'ambient en el qual un agent cognitiu es desenvolupa i pel cos de l'agent per se. Fins i tot, els processos de desenvolupament que ocorren a nivell físic, cognitiu i social també regulen què és après i quan això ès après. La primera part d'aquest treball proveeix el lector amb les evidencies teòrica i pràctica que demostren la rellevància d'aquesta investigació. Recorrent conceptes que van des de les ciències cognitives i del desenvolupament, vam arribar a la conclusió que el llenguatge, i per tant la parla, han de ser estudiats com a fenòmens cognitius que requereixen un cos físic i a més un ambient propici per a la seva existència. En l'actualitat els sistemes robòtics, reals i simulats, poden ser considerats com a elements per a l'estudi dels fenòmens cognitius naturals. En aquest treball considerem un exemple simple per provar les arquitectures cognitives que proposem, i posteriorment utilitzem aquestes arquitectures amb un sintetitzador de veu similar al mecanisme humà de producció de la parla. Com a primera contribució d'aquest treball proposem introduir un mecanisme per construir robots capaços de considerar les seves pròpies restriccions motores durant l'etapa d'autoexploració sensorimotora. Certs mecanismes de motivació intrínseca per exploració sensorimotora han estat estudiats com a possibles conductors de les trajectòries de desenvolupament observades durant el desenvolupament primerenc de la parla. No obstant això, en previs estudis no es va considerar que aquest desenvolupament és delimitat per restriccions a causa de l'ambient, el cos físic, i les capacitats sensorials, motores i cognitives. A la nostra arquitectura, assumim que un agent artificial no compta amb coneixement dels seus limitants motors, i per tant ha de descobrir-los durant l'etapa d'autoexploració. Per a tal efecte, l'agent és proveït d'un sistema somatosensorial que li indica quan una configuració motora viola les restriccions imposades pel propi cos. Finalment, com a segona part de la nostra contribució proposem incloure un mecanisme per reforçar l'aprenentatge durant l'autoexploració. Estudis anteriors han demostrat que l'ambient lingüísticstic en què es desenvolupa un infant, o un agent artificial, condiciona les seves produccions vocals durant l'autoexploració o balboteig. En aquest treball ens enfoquem en l'estudi d'episodis d’imitació que ocorren durant el desenvolupament primerenc d'un agent. Basats en estudis sobre la interacció entre mares i fills durant l'etapa prelingüística, proposem un mecanisme per reforçar l'aprenentatge durant l'autoexploració amb unitats sensorials rellevants. Aleshores, a partir de l'arquitectura amb autoconeixement de restriccions motors, vam construir una arquitectura que inclou un instructor expert en control sensorimotor. Les interaccions entre l'aprenent i l'expert, ocorren quan una producció sensorial de l'aprenent durant l'autoexploració és similar a una unitat sensorial rellevant per a la comunicació. En aquest cas, l'expert percep aquesta similitud i respon reformulant la producció de l'aprenent com la unitat rellevant. Quan l'aprenent percep una acció de l'expert, immediatament intenta imitar-lo. Els resultats presentats en aquest treball suggereixen que els sistemes somatosensorials i el reforçament social contribueixen a aconseguir millors resultats durant l'etapa d'autoexploració sensorimotora motivada intrínsecament. En aquest sentit, s'aconsegueix una exploració menys redundant, els errors d’exploració i avaluació disminueixen, i finalment s’obté una imatge més nítida de les transicions entre etapes del desenvolupament
Belaid, Mohamed-Bachir. "Declarative Itemset Mining Based on Constraint Programming". Thesis, Montpellier, 2020. http://www.theses.fr/2020MONTS004.
Pełny tekst źródłaData mining is the art of discovering knowledge from databases. The user specifies the type of patterns to be mined, and the miner uses techniques to find the required patterns. Many techniques have been introduced for mining traditional patterns like frequent itemsets, association rules, etc. However, mining patterns with additional properties remains a bottleneck for specialists nowadays due to the algorithmic effort needed to handle these properties.Recently, researchers have taken advantage of the flexibility of constraint programming to model various data mining problems. In terms of CPU time, constraint programming-based methods have not yet competed with ad hoc algorithms. However, their flexibility allows the modeling of complex user queries without revising the solving process.In this thesis we propose to use constraint programming for modeling and solving some well known data mining problems.Our first contribution is a constraint programming model for mining association rules. To implement our model, we introduce a new global constraint, CONFIDENT, for ensuring the confidence of rules.We prove that completely propagating CONFIDENT is NP-hard. We thus provide a non-complete propagator and a decomposition for CONFIDENT. We also capture the minimal non-redundant rules, a condensed representation of association rules, by introducing the global constraint GENERATOR. GENERATOR is used for mining itemsets that are generators. For this constraint, we propose a complete polynomial propagator.Our second contribution is a generic framework based on constraint programming to mine both borders of frequent itemsets, i.e. the positive border or maximal frequent itemsets and the negative border or minimal infrequent itemsets. One can easily decide which border to mine by setting a simple parameter. For this, we introduce two new global constraints, FREQUENTSUBS and INFREQUENTSUPERS, with complete polynomial propagators. We then consider the problem of mining borders with additional constraints. We prove that this problem is coNP-hard, ruling out the hope for the existence of a single CSP solving this problem (unless coNP is in NP)
Pillay, Poobalan. "An empirical exploration of supply chain constraints facing the construction industry in South Africa". Thesis, Vaal University of Technology, 2016. http://hdl.handle.net/10352/382.
Pełny tekst źródłaGuerrera, Christine. "Flexibility and constraint in lexical access: Explorations in transposed-letter priming". Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/280702.
Pełny tekst źródłaZhao, Jing. "Household debt service burden outlook an exploration on the effect of credit constraints /". Connect to this title online, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1054650767.
Pełny tekst źródłaTitle from first page of PDF file. Document formatted into pages; contains xii, 210 p.; also includes graphics (some col.) Includes bibliographical references (p. 203-210). Available online via OhioLINK's ETD Center
Gharbi, Amna. "Constraint programming for design space exploration of dataflow applications on multi-bus architectures". Electronic Thesis or Diss., Institut polytechnique de Paris, 2021. http://www.theses.fr/2021IPPAT018.
Pełny tekst źródłaThis thesis is part of a collaboration between Télécom Paris and Nokia Bell Labs France. In this context, we focus on the system-level Design Space Exploration of embedded systems for the execution of signal processing applications. In the system we target, the design space exploration process intends to identify the allocation and scheduling of both application tasks and data transfers between these tasks: this identification plays a key role in the overall performance (e.g. end-to-end latency) of these systems. While there are already multiple works for diverse communication architectures, this thesis focuses on multi-bus architectures that are particularly well-suited for computation platforms of signal processing applications. For these platforms, we show that only limited contributions have already been proposed. Three contributions are proposed to tackle the above mentioned problem. 1) A satisfiability modulo theories (SMT) formulation which allows to explore mapping and scheduling decisions on multi-bus architectures for latency optimization; We demonstrate its ability to produce a solution for well-known applications. Yet, 2) to mitigate the scalability limitations for the optimal solution search of this first contribution, we propose a technique to prune the design space of searched solutions. Evaluations we provide demonstrate a better scalability. Last, 3) communication allocation is enhanced with power consumption, and we show how to jointly optimize latency and power consumption. Our evaluation is again applied to a set of well-known signal processing applications and demonstrates how different trade-offs between latency and power consumption can be studied.Our contributions are integrated into a state-of-the-art modeling and verification tool for the system-level design of embedded systems (TTool). Perspectives are articulated in mainly two axes. 1) Extending the current formulation to account for new design aspects (e.g., shared memory, throughput). 2) Further improving the scalability of the optimal search
Le, Calvar Théo. "Exploration d’ensembles de modèles". Thesis, Angers, 2019. http://www.theses.fr/2019ANGE0035.
Pełny tekst źródłaModel transformation has proven to be an effective technique to produce target models from source models. Most transformation approaches focus on generating a single target model from a given source model. However there are situations where a collection of possible target models is preferred over a single one. Such situations arise when some choices cannot be encoded in the transformation. Then, search techniques can be used to help select a target model having specific properties. In this thesis, we present an approach combining model transformation with constraint solving to generate and explore these model sets. Moreover, we present two implementations of this approach along with multiple case studies showcasing these implementations and there usefulness
Boonvisut, Pasu. "Active Exploration of Deformable Object Boundary Constraints and Material Parameters Through Robotic Manipulation Data". Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1369078402.
Pełny tekst źródłaMthimkhulu, Alfred Mbekezeli. "Small enterprise development in South Africa : an exploration of the constraints and job creation potential". Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97117.
Pełny tekst źródłaENGLISH ABSTRACT: This thesis, presented in six thematic chapters, investigates an approach for promoting the growth of small businesses in South Africa. Chapter 1 motivates the thesis by discussing the contested role of small businesses in reducing unemployment and fostering social equity. Chapter 2 reviews the small business development policy in South Africa and explicates the socioeconomic conditions underpinning the policy. Chapters 3, 4 and 5 are empirical analyses using data from the World Bank Enterprise Surveys of 2003 and 2007, and the World Bank Financial Crisis Survey of 2010 to determine key impediments to the growth of small businesses and characteristics of firms creating and retaining most jobs in South Africa. Chapter 3 uses two methods to investigate the key impediments. The first method is based on a count of obstacles that entrepreneurs rate as seriously affecting enterprise operations. The second estimates the effects of the obstacles on growth through sequential multivariate regressions and identifies binding constraints for different categories of firms. It emerges that medium-sized firms are mildly affected by most obstacles but micro and small firms are significantly affected by crime, electricity and transportation problems. The chapter provides important insight on the sequencing of interventions to address the impediments to growth. Chapter 4 studies the finance constraint. It evaluates the importance of the constraint firstly by assessing whether firms rating finance as a serious problem underperform firms rating the problem as less important. Thereafter, the chapter studies the experiences of firms when seeking external finance and identifies four levels of the finance constraint. Using an ordered logit model and a binary logit model, the chapter explores the profile of financially constrained firms. Results show that firms owned by ethnic groups disadvantaged in the apartheid era are more likely to be credit-constrained. The results also suggest that the likelihood of being credit-constrained decreases with higher levels of formal education. The results inform policy on the types of firms that financial interventions must target. Chapter 5 builds on a growing body of evidence which shows that a small proportion of firms in an economy account for over 50 percent of net new jobs. The evidence from the literature suggests that such high-growth enterprises have distinct characteristics that could make it possible for interventions to nurture or for other firms to emulate. The chapter employs two methods to investigate the characteristics of high-growth firms. The first is logit regression, which the investigation uses to determine characteristics of firms that create more jobs than the average firm. The characteristics are also interacted to identify interaction terms most associated with growth. The second method is quantile regression, which makes it possible to assess the importance of each characteristic for firms in different levels of growth rates. The results show that the typical high-growth firm is more likely to be black-owned. The results of the chapter however highlight the need for further research into characteristics that may perhaps explain high-growth firms more robustly than variables in the survey instrument. The research ends with a summary, a discussion of areas of further research, and policy recommendations in Chapter 6.
Hernández, Vega Juan David. "Online path planning for autonomous underwater vehicles under motion constraints". Doctoral thesis, Universitat de Girona, 2017. http://hdl.handle.net/10803/457592.
Pełny tekst źródłaLes aplicacions més comunes dels vehicles autònoms submarins o AUVs són l’obtenció d'imatges i inspecció de diferents tipus d'estructures, com per exemple, cascos de vaixells o estructures naturals en el fons marí. Moltes d'aquestes aplicacions requereixen informació a priori de l'àrea o estructura que es vol inspeccionar. No obstant, existeixen aplicacions similars o noves, com l'exploració d'entorns naturals confinats (e.g., coves submarines), on aquesta informació pot ser inexistent. En aquest sentit, aquesta tesi presenta una alternativa per dotar un AUV amb l'habilitat de moure’s a través d'entorns no explorats. Per aconseguir aquesta fita, aquesta tesi proposa un mètode per calcular en temps real camins factibles i segurs. El mètode proposat permet al vehicle construir de forma incremental un mapa de l'entorn, i al mateix temps replanificar un camí factible cap a l'objectiu establert. El mètode proposat te en compte les restriccions de moviment del vehicle per planificar camins que siguin factibles
Phan, Leon L. "A methodology for the efficient integration of transient constraints in the design of aircraft dynamic systems". Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34750.
Pełny tekst źródłaFell, Alison. "Agoraphobia : mental disorder or societal constraint? : a gendered exploration of symptoms of agoraphobia in a non-clinical population". Thesis, University of East London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.532493.
Pełny tekst źródłaMcLaughlin, Josetta S. "Operationalalizing social contract: application of relational contract theory to exploration of constraints on implementation of an employee assistance program". Diss., Virginia Tech, 1993. http://hdl.handle.net/10919/39741.
Pełny tekst źródłaLasbouygues, Adrien. "Exploration robotique de l’environnement aquatique : les modèles au coeur du contrôle". Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS078/document.
Pełny tekst źródłaUnderwater robots can nowadays operate in complex environments in a broad scope of missions where the use of human divers is difficult for cost or safety reasons. However the complexity of aquatic environments requires to give the robotic vector an autonomy sufficient to perform its mission while preserving its integrity. This requires to design control laws according to application requirements. They are built on knowledge from several scientific fields, underlining the interdisciplinarity inherent to robotics. Once the control law designed, it must be implemented as a control Software working on a real-time Software architecture.Nonetheless the current conception of control laws, as "monolithic" blocks, makes difficult the adaptation of a control from an application to another and the integration of knowledge from various scientific fields which are often not fully understood by control engineers. It also penalizes the implementation of control on Software architectures, at least its modularity and evolution. To solve those problems we seek a proper separation of knowledge so that each knowledge item can be easily used, its role precisely defined and we want to reify the interactions between them. Moreover this will allow us a more efficient projection on the Software architecture. We thus propose a new formalism for control laws description as a modular composition of basic entities named Atoms used to encapsulate the knowledge items.We also aim at building a better synergy between control and software engineering based on shared concerns such as temporal constraints and stability. Hence we extend the definition of our Atoms with constraints carrying information related to their temporal behaviour. We propose as well a methodology relying on our formalism to guide the implementation of control on a real-time Middleware. We will focus on the ContrACT Middleware developed at LIRMM.Finally we illustrate our approach on several robotic functionalities that can be used during aquatic environments exploration and especially for wall avoidance during the exploration of a karst aquifer
Karakus, Mehmet. "From constraint to opportunity : an exploration of Ireland and Sweden's experience of relating neutrality to participation in EU's CFSP". Thesis, University of Newcastle Upon Tyne, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251338.
Pełny tekst źródłaMarcus, Ventovaara, i Hasanbegović Arman. "A Method for Optimised Allocation of System Architectures with Real-time Constraints". Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-39492.
Pełny tekst źródłaLartigue, Thomas. "Mixtures of Gaussian Graphical Models with Constraints Gaussian Graphical Model exploration and selection in high dimension low sample size setting". Thesis, Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAX034.
Pełny tekst źródłaDescribing the co-variations between several observed random variables is a delicate problem. Dependency networks are popular tools that depict the relations between variables through the presence or absence of edges between the nodes of a graph. In particular, conditional correlation graphs are used to represent the “direct” correlations between nodes of the graph. They are often studied under the Gaussian assumption and consequently referred to as “Gaussian Graphical Models” (GGM). A single network can be used to represent the overall tendencies identified within a data sample. However, when the observed data is sampled from a heterogeneous population, then there exist different sub-populations that all need to be described through their own graphs. What is more, if the sub-population (or “class”) labels are not available, unsupervised approaches must be implemented in order to correctly identify the classes and describe each of them with its own graph. In this work, we tackle the fairly new problem of Hierarchical GGM estimation for unlabelled heterogeneous populations. We explore several key axes to improve the estimation of the model parameters as well as the unsupervised identification of the sub-populations. Our goal is to ensure that the inferred conditional correlation graphs are as relevant and interpretable as possible. First - in the simple, homogeneous population case - we develop a composite method that combines the strengths of the two main state of the art paradigms to correct their weaknesses. For the unlabelled heterogeneous case, we propose to estimate a Mixture of GGM with an Expectation Maximisation (EM) algorithm. In order to improve the solutions of this EM algorithm, and avoid falling for sub-optimal local extrema in high dimension, we introduce a tempered version of this EM algorithm, that we study theoretically and empirically. Finally, we improve the clustering of the EM by taking into consideration the effect of external co-features on the position in space of the observed data
Menezes, Jeffrey Louis. "Use of isoperformance, constraint programming, and mixed integer linear programing for architecture tradespace exploration of passive Optical Earth Observation Systems". Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/119313.
Pełny tekst źródłaThesis: M.B.A., Massachusetts Institute of Technology, Sloan School of Management 2018 In conjunction with the Leaders for Global Operations Program at MIT
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 147-150).
This thesis presents work performed during the course of an internship at An Aerospace Company (AAC) and research performed at Massachusetts Institute of Technology (MIT) Lincoln Laboratory as part of a fellowship. Both efforts entailed the development of architecture tradespace exploration models for space systems. The tradespace exploration model developed at AAC, called the Earth Observation Architecture Isoperformance Model (EO-AIM), uses automation techniques, isoperformance, and constraint programming to rapidly construct potential space-based passive optical EO sensor architecture concepts which meet a given set of customer requirements. Cost estimates are also generated for each sensor concept via integration with stakeholder-trusted cost modeling software allowing for cost to be treated as both an independent variable and consequence when evaluating various architecture solutions. The EO-AIM then uses simple algorithms to identify potential satellite bus options for hosting each sensor architecture in orbit. The total cost of populating an entire constellation based on the sensor architecture is finally estimated using cost estimates for the sensor, satellite bus, and the best launch vehicle option capable of lifting the satellite(s) to orbit. In general, the EO-AIM seeks to bolster's AAC's capabilities for conducting architecture trade space exploration and initial proposal development given advancements in satellite bus, launch vehicle, and sensing technologies. The tradespace exploration model developed at MIT Lincoln Laboratory is a satellite network mixed integer linear program (MILP) which is used for making system architecture decisions and estimating final architecture cost. The satellite network MILP is formulated as both an assignment problem and a network maximum flow problem which must send sensor generated data to a ground user. Results of the MILP vary with the selected objective function and provide insights on the potential benefits of architecture decisions such as sensor disaggregation and the utility of introducing additional communication nodes into existing networks. The satellite network MILP is also capable of verifying network data volume throughput capacity and providing an optimized link schedule for the duration of the simulation. Overall, the satellite network MILP model explores the general problem of optimizing use of limited resources for a given space-based sensor while ensuring mission data needs are met. It is a higher fidelity alternative to the simple satellite bus and launch vehicle compatibility algorithm used in EO-AIM. Both models are shown to improve architecture tradespace exploration of space-based passive-optical EO systems. With a simple demonstration, it is exhibited that using the EO-AIM can increase sensor architecture concepts generated by a factor of ten or more by creating all feasible sensor architecture concepts given user inputs and settings. Furthermore, the use of the satellite network MILP to examine alternative network architecture options for NASA's HyspIRI mission resulted in a system architecture with 20% higher data throughput for marginally less cost.
by Jeffrey Louis Menezes.
S.M.
M.B.A.
Von, Blottnitz Magali. "Dysfunctional market or insufficient creditworthiness? : an exploration of financial constraint experienced by small, medium and micro enterprises in South Africa". Doctoral thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/5620.
Pełny tekst źródłaIncludes bibliographical references (p. 212-228 ).
The existence and prevalence of financial constraints has been extensively discussed in the international economic literature, and is implicit in debates on the performance and needs of South Africa’s Small, Medium and Micro Enterprises (SMMEs). However, there is little solid research measuring financial constraints among South African SMMEs. In addition, the reasons advanced for their financial constraints are often speculative and anecdotal rather than the result of sound research. The hypothesis of credit rationing, resulting from information asymmetries, is well established in theory but an additional explanatory hypothesis, the fragile financial structure of SMMEs, is often voiced by the South African finance community. With South African data being scarce and patchy, none of these hypotheses has been validated by empirical studies. The most likely reason for these gaps in literature is not a lack of interest, but the considerable difficulty of raising reliable data from SMMEs, a joint result of confidentiality, widespread informality in the sector, and the limitations of publicly available statistics in developing countries. Surveys of banks or SMMEs raise risks of partiality and limited ability of respondents to provide quantitative data, while accounting data are characterised by limited usability and reliability. This thesis attempts to address those challenges by exploring primary and secondary sources of data, combining the respective strengths of interview and financial data.
Zine, Elabidine Khouloud. "Méthode de prototypage virtuel permettant l'évaluation précoce de la consommation énergétique dans les systèmes intégrés sur puce". Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066669/document.
Pełny tekst źródłaTechnological trends towards high-level integration combined with the increasing operating frequencies, made embedded systems design become more and more complex.The increase in number of computing resources in integrated circuit (IC) led toover-constrained systems.In fact, SoC (System on Chip) designers must reduce overall system costs, including board space, power consumption and development time.Although many researches have developed methodologies to deal with the emerging requirements of IC design, few of these focused on the power consumption constraint.While the highest accuracy is achieved at the lowest level, estimation time increases significantly when we move down to lower levels.Early power estimation is interesting since it allows to widely explore the architectural design space during the system level partitioning and to early adjust architectural design choices.EDPE estimates power consumption at the system levels and especially CABA (Cycle Accurate Bit Accurate) and TLM (Transaction Level Modelling) levels.The EDPE have been integrated into SoCLib library.The main goal of EDPE (Early Design Power Estimation) is to compare the power consumption of different design partitioning alternatives and chooses the best trade-off power/ performance.Experimental results show that EDPE (Early Design Power Estimation) method provides fast, yet accurate, early power estimation for MPSoCs (MultiprocessorSystem on Chip).EDPE uses few parameters per hardware components and is based on homogeneous and easy characterization method.EDPE is easily generalized to any virtual prototyping library
Rathnam, Ravi Kulan [Verfasser], Andreas [Akademischer Betreuer] Birk, Kaustubh [Akademischer Betreuer] Pathak i Dieter [Akademischer Betreuer] Kraus. "Distributive Cooperative 3D Exploration under Range Communication Constraints / Ravi Kulan Rathnam. Betreuer: Andreas Birk. Gutachter: Andreas Birk ; Kaustubh Pathak ; Dieter Kraus". Bremen : IRC-Library, Information Resource Center der Jacobs University Bremen, 2015. http://d-nb.info/1087324033/34.
Pełny tekst źródłaZine, Elabidine Khouloud. "Méthode de prototypage virtuel permettant l'évaluation précoce de la consommation énergétique dans les systèmes intégrés sur puce". Electronic Thesis or Diss., Paris 6, 2014. http://www.theses.fr/2014PA066669.
Pełny tekst źródłaTechnological trends towards high-level integration combined with the increasing operating frequencies, made embedded systems design become more and more complex.The increase in number of computing resources in integrated circuit (IC) led toover-constrained systems.In fact, SoC (System on Chip) designers must reduce overall system costs, including board space, power consumption and development time.Although many researches have developed methodologies to deal with the emerging requirements of IC design, few of these focused on the power consumption constraint.While the highest accuracy is achieved at the lowest level, estimation time increases significantly when we move down to lower levels.Early power estimation is interesting since it allows to widely explore the architectural design space during the system level partitioning and to early adjust architectural design choices.EDPE estimates power consumption at the system levels and especially CABA (Cycle Accurate Bit Accurate) and TLM (Transaction Level Modelling) levels.The EDPE have been integrated into SoCLib library.The main goal of EDPE (Early Design Power Estimation) is to compare the power consumption of different design partitioning alternatives and chooses the best trade-off power/ performance.Experimental results show that EDPE (Early Design Power Estimation) method provides fast, yet accurate, early power estimation for MPSoCs (MultiprocessorSystem on Chip).EDPE uses few parameters per hardware components and is based on homogeneous and easy characterization method.EDPE is easily generalized to any virtual prototyping library
Merino, Perez Irene. "Geophysical constraints on the nature of geological domains of continental rifted margins: examples from the West Iberia margin and Ligurian Basin". Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/673631.
Pełny tekst źródłaEn esta tesis doctoral, se ha realizado un estudio geofísico y geológico de dos ejemplos clásicos de márgenes continentales: el margen de la Cuenca de Liguria y el margen de la Llanura Abisal del Tajo, ubicada en el margen Oeste de Iberia. A pesar de los diversos estudios previos de estas regiones, existe un debate abierto tanto sobre su estructura cortical como sobre los procesos que operaban durante su formación. Este trabajo de tesis ha tenido como objetivos: 1) determinar la naturaleza de las rocas que forman los principales dominios geológicos de ambos márgenes, 2) definir la estructura tectónica del basamento y 3) discutir la cinemática y la interacción de mecanismos tectónicos y magmáticos involucrados en la formación de los márgenes. Para conseguir estos objetivos, se han analizado e integrado diversos datos geofísicos. Los datos principales son de sísmica de reflexión de “streamer” multicanal y de sísmica de refracción y refracción de gran ángulo marinos. También se han integrado datos batimétricos y gravimétricos. La parte metodológica más novedosa de esta tesis es la utilización de los tiempos de trayecto de fases sísmicas de datos de streamer y gran ángulo en una tomografía conjunta. Esta metodología permite determinar con más precisión que otros métodos las velocidades de las ondas sísmicas (Vp) a través del basamento a lo largo de los perfiles. El modelo resultante permite establecer la naturaleza petrológica con menos incertidumbre que los métodos más comúnmente usados. El análisis, procesamiento, modelado e interpretación de estos conjuntos de datos permite una interpretación novedosa de los aspectos relacionados con la estructura y naturaleza de la corteza, así como la discusión de nuevas propuestas para los procesos tectónicos que llevaron a la configuración actual de cada uno de los ejemplos de márgenes continentales. La interpretación desarrollada difiere en gran medida de modelos previos en cuanto a la formación de ambos sistemas de rifting. Por ello, proponemos que su integración ofrece la oportunidad de revisar modelos conceptuales existentes en la literatura. En particular, los resultados muestran que la respuesta de la litosfera continental a los procesos de extensión puede ser más compleja de lo que se suponía hasta ahora.
Vigneron, Vincent. "Programmation par contraintes et découverte de motifs sur données séquentielles". Thesis, Angers, 2017. http://www.theses.fr/2017ANGE0028/document.
Pełny tekst źródłaRecent works have shown the relevance of constraint programming to tackle data mining tasks. This thesis follows this approach and addresses motif discovery in sequential data. We focus in particular, in the case of classified sequences, on the search for motifs that best fit each individual class. We propose a language of constraints over matrix domains to model such problems. The language assumes a preprocessing of the data set (e.g., by pre-computing the locations of each character in each sequence) and views a motif as the choice of a sub-matrix (i.e., characters, sequences, and locations). We introduce different matrix constraints (compatibility of locations with the database, class covering, location-based character ordering common to sequences, etc.) and address two NP-complete problems: the search for class-specific totally ordered motifs (e.g., exclusive subsequences) or partially ordered motifs. We provide two CSP models that rely on global constraints to prove exclusivity. We then present a memetic algorithm that uses this CSP model during initialisation and intensification. This hybrid approach proves competitive compared to the pure CSP approach as shown by experiments carried out on protein sequences. Lastly, we investigate data set preprocessing based on patterns rather than characters, in order to reduce the size of the resulting matrix domain. To this end, we present and compare two alternative methods, one based on lattice search, the other on dynamic programming
Guillame-Bert, Mathieu. "Apprentissage de règles associatives temporelles pour les séquences temporelles de symboles". Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENM081/document.
Pełny tekst źródłaThe learning of temporal patterns is a major challenge of Data mining. We introduce a temporal pattern model called Temporal Interval Tree Association Rules (Tita rules or Titar). This pattern model can be used to express both uncertainty and temporal inaccuracy of temporal events. Among other things, Tita rules can express the usual time point operators, synchronicity, order, and chaining,disjunctive time constraints, as well as temporal negation. Tita rules are designed to allow predictions with optimum temporal precision. Using this representation, we present the Titar learner algorithm that can be used to extract Tita rules from large datasets expressed as Symbolic Time Sequences. This algorithm based on entropy minimization, apriori pruning and statistical dependence analysis. We evaluate our technique on simulated and real world datasets. The problem of temporal planning with Tita rules is studied. We use Tita rules as world description models for a Planning and Scheduling task. We present an efficient temporal planning algorithm able to deal with uncertainty, temporal inaccuracy, discontinuous (or disjunctive) time constraints and predictable but imprecisely time located exogenous events. We evaluate our technique by joining a learning algorithm and our planning algorithm into a simple reactive cognitive architecture that we apply to control a robot in a virtual world
Bekkouche, Mohammed. "Combinaison des techniques de Bounded Model Checking et de programmation par contraintes pour l'aide à la localisation d'erreurs : exploration des capacités des CSP pour la localisation d'erreurs". Thesis, Nice, 2015. http://www.theses.fr/2015NICE4096/document.
Pełny tekst źródłaA model checker can produce a trace of counter-example for erroneous program, which is often difficult to exploit to locate errors in source code. In my thesis, we proposed an error localization algorithm from counter-examples, named LocFaults, combining approaches of Bounded Model-Checking (BMC) with constraint satisfaction problem (CSP). This algorithm analyzes the paths of CFG (Control Flow Graph) of the erroneous program to calculate the subsets of suspicious instructions to correct the program. Indeed, we generate a system of constraints for paths of control flow graph for which at most k conditional statements can be wrong. Then we calculate the MCSs (Minimal Correction Sets) of limited size on each of these paths. Removal of one of these sets of constraints gives a maximal satisfiable subset, in other words, a maximal subset of constraints satisfying the postcondition. To calculate the MCSs, we extend the generic algorithm proposed by Liffiton and Sakallah in order to deal with programs with numerical instructions more efficiently. This approach has been experimentally evaluated on a set of academic and realistic programs
Ngo, Tu. "Decision support system for enhancing health care services to reduce potentially avoidable hospitalizations". Thesis, Montpellier, 2020. http://www.theses.fr/2020MONTS035.
Pełny tekst źródłaPotentially avoidable hospitalizations (PAHs) are the hospital admissions that could have been prevented with timely and effective treatments. The high rates of PAHs are associated with many factors. These factors include high mortality rates, low density of primary care physicians, lack of continuity of care, and lack of access to primary care, low median income or low education levels as well as organizational features of health systems such as poor coordination between health care providers. On the other side, in France, there are about 300,000 PAHs every year. These preventable hospitalizations are associated with a cost of several hundred million Euros for the Health Insurance. In other words, reducing PAHs not only enhances patients’ quality of life but also could save substantial costs due to patient treatments. Therefore, health authorities are highly interested in solutions improving health care services to reduce PAHs.Some recent studies in France have suggested that increasing the number of nurses in selected geographic areas could lead to the reduction of the rates of PAHs in those areas. In our approach, after evaluating some common regression methods, we extended the support vector machine for regression to spatial information. This approach allows us to select not only the geographic areas but also the number of to-be-added nurses in these areas for the biggest reduction in the number of PAHs. Specifically, our approach is applied in the Occitanie region, France and geographic areas mentioned above are the cross-border living areas (fr. Bassins de vie - BVs). However, our approach can be extended at the national level or to other regions or countries.On the other side, the extreme temperature could be one potential factor associated with high rates of PAHs. Therefore, a part of our works is to measure the impact of the extreme temperature to PAHs as well as to include this environmental data in our approach above. In our works, we used the temperature values measured hourly by sensors at the weather stations. However, these values are sometimes discontinuous and we need an imputation method for these missing values. In the literature, two most popular approaches dealing with this processing step exploit either the spatial component or temporal component of the temperature data. Respectively, these approaches are spatial interpolation methods such as Inverse Distance Weighted (IDW) and time-series models such as Autoregressive Integrated Moving Average (ARIMA). To help us select the more reliable method, we first compare the performances of both approaches. In addition, we propose a novel approach that combines both dimensions to improve the performance in terms of quality. The results show that compared with IDW and ARIMA methods, our approach performs better at 100% and 99.8% (604 over 605) weather stations respectively.In addition, as mentioned at the beginning, improving the coordination between the health care providers could lead to the reduction of the PAHs. Moreover, in the cases that the patients change hospitals for treatments, to ensure efficient and high-quality treatments, doctors would need access to the patients’ medical records at the previous hospitals. Therefore, health authorities are interested in building hospital communities whereby medical records can be shared among the hospitals. Therefore, we propose a graph-based approach to address this problem. Particularly, we first model data flows of patients between hospitals as an undirected weighted graph in which nodes and edges present the hospitals and the amount of patient flows respectively. Then, after evaluating two common graph clustering methods, we customize the more suitable one for our needs. Our result provides interesting insights compared with approaches based on administrative boundaries
Ferdjoukh, Adel. "Une approche déclarative pour la génération de modèles". Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT325/document.
Pełny tekst źródłaOwning data is useful in many different fields. Data can be used to test and to validate approaches, algorithms and concepts. Unfortunately, data is rarely available, is cost to obtain, or is not adapted to most of cases due to a lack of quality.An automated data generator is a good way to generate quickly and easily data that are valid, in different sizes, likelihood and diverse.In this thesis, we propose a novel and complete model driven approach, based on constraint programming for automated data generation
Zalila, Faiez. "Methods and tools for the integration of formal verification in domain-specific languages". Phd thesis, Toulouse, INPT, 2014. http://oatao.univ-toulouse.fr/14159/1/zalila.pdf.
Pełny tekst źródłaBen, Zakour Asma. "Extraction des utilisations typiques à partir de données hétérogènes en vue d'optimiser la maintenance d'une flotte de véhicules". Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14539/document.
Pełny tekst źródłaThe present work is part of an industrial project driven by 2MoRO Solutions company.It aims to develop a high value service enabling aircraft operators to optimize their maintenance actions.Given the large amount of data available around aircraft exploitation, we aim to analyse the historical events recorded with each aircraft in order to extract maintenance forecasting. Theresults are used to integrate and consolidate maintenance tasks in order to minimize aircraft downtime and risk of failure. The proposed method involves three steps : (i) streamlining information in order to combinethem, (ii) organizing this data for easy analysis and (iii) an extraction step of useful knowledgein the form of interesting sequences. [...]
Abboud, Yacine. "Fouille de motifs : entre accessibilité et robustesse". Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0176/document.
Pełny tekst źródłaInformation now occupies a central place in our daily lives, it is both ubiquitous and easy to access. Yet extracting information from data is often an inaccessible process. Indeed, even though data mining methods are now accessible to all, the results of these mining are often complex to obtain and exploit for the user. Pattern mining combined with the use of constraints is a very promising direction of the literature to both improve the efficiency of the mining and make its results more apprehensible to the user. However, the combination of constraints desired by the user is often problematic because it does not always fit with the characteristics of the searched data such as noise. In this thesis, we propose two new constraints and an algorithm to overcome this issue. The robustness constraint allows to mine noisy data while preserving the added value of the contiguity constraint. The extended closedness constraint improves the apprehensibility of the set of extracted patterns while being more noise-resistant than the conventional closedness constraint. The C3Ro algorithm is a generic sequential pattern mining algorithm that integrates many constraints, including the two new constraints that we have introduced, to provide the user the most efficient mining possible while reducing the size of the set of extracted patterns. C3Ro competes with the best pattern mining algorithms in the literature in terms of execution time while consuming significantly less memory. C3Ro has been experienced in extracting competencies from web-based job postings
Boulil, Kamal. "Une approche automatisée basée sur des contraintes d’intégrité définies en UML et OCL pour la vérification de la cohérence logique dans les systèmes SOLAP : applications dans le domaine agri-environnemental". Thesis, Clermont-Ferrand 2, 2012. http://www.theses.fr/2012CLF22285/document.
Pełny tekst źródłaSpatial Data Warehouse (SDW) and Spatial OLAP (SOLAP) systems are Business Intelligence (BI) allowing for interactive multidimensional analysis of huge volumes of spatial data. In such systems the quality ofanalysis mainly depends on three components : the quality of warehoused data, the quality of data aggregation, and the quality of data exploration. The warehoused data quality depends on elements such accuracy, comleteness and logical consistency. The data aggregation quality is affected by structural problems (e.g., non-strict dimension hierarchies that may cause double-counting of measure values) and semantic problems (e.g., summing temperature values does not make sens in many applications). The data exploration quality is mainly affected by inconsistent user queries (e.g., what are temperature values in USSR in 2010?) leading to possibly meaningless interpretations of query results. This thesis address the problems of logical inconsistency that may affect the data, aggregation and exploration qualities in SOLAP. The logical inconsistency is usually defined as the presence of incoherencies (contradictions) in data ; It is typically controlled by means of Integrity Constraints (IC). In this thesis, we extends the notion of IC (in the SOLAP domain) in order to take into account aggregation and query incoherencies. To overcome the limitations of existing approaches concerning the definition of SOLAP IC, we propose a framework that is based on the standard languages UML and OCL. Our framework permits a plateforme-independent conceptual design and an automatic implementation of SOLAP IC ; It consists of three parts : (1) A SOLAP IC classification, (2) A UML profile implemented in the CASE tool MagicDraw, allowing for a conceptual design of SOLAP models and their IC, (3) An automatic implementation based on the code generators Spatial OCLSQL and UML2MDX, which allows transforming the conceptual specifications into code. Finally, the contributions of this thesis have been experimented and validated in the context of French national projetcts aimming at developping (S)OLAP applications for agriculture and environment
Merabet, Massinissa. "Solutions optimales des problèmes de recouvrement sous contraintes sur le degré des nœuds". Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20138/document.
Pełny tekst źródłaThe work conducted in this thesis is focused on the minimum spanning problems in graphs under constraints on the vertex degrees. As the spanning tree covers the vertices of a connected graph with a minimum number of links, it is generally proposed as a solution for this kind of problems. However, for some applications such as the routing in optical networks, the solution is not necessarily a sub-graph. In this thesis, we assume that the degree constraints are due to a limited instantaneous capacity of the vertices and that the only pertinent requirement on the spanning structure is its connectivity. In that case, the solution may be different from a tree. We propose the reformulation of this kind of spanning problems. To find the optimal coverage of the vertices, an extension of the tree concept called hierarchy is proposed. Our main purpose is to show its interest regarding the tree in term of feasibility and costs of the coverage. Thus, we take into account two types of degree constraints: either an upper bound on the degree of vertices and an upper bound on the number of branching vertices. We search a minimum cost spanning hierarchy in both cases. Besides, we also illustrate the applicability of hierarchies by studying a problem that takes more into account the reality of the optical routing. For all those NP-hard problems, we show the interest of the spanning hierarchy for both costs of optimal solutions and performance guarantee of approximate solutions. These results are confirmed by several experimentations on random graphs
Julea, Andreea Maria. "Extraction de motifs spatio-temporels dans des séries d'images de télédétection : application à des données optiques et radar". Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00652810.
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