Dissertations / Theses on the topic 'POMDPs'
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Aras, Raghav Charpillet François Dutech Alain. "Mathematical programming methods for decentralized POMDPs." S. l. : Nancy 1, 2008. http://www.scd.uhp-nancy.fr/docnum/SCD_T_2008_0092_ARAS.pdf.
Full textAras, Raghav. "Mathematical programming methods for decentralized POMDPs." Thesis, Nancy 1, 2008. http://www.theses.fr/2008NAN10092/document.
Full textIn this thesis, we study the problem of the optimal decentralized control of a partially observed Markov process over a finite horizon. The mathematical model corresponding to the problem is a decentralized POMDP (DEC-POMDP). Many problems in practice from the domains of artificial intelligence and operations research can be modeled as DEC-POMDPs. However, solving a DEC-POMDP exactly is intractable (NEXP-hard). The development of exact algorithms is necessary in order to guide the development of approximate algorithms that can scale to practical sized problems. Existing algorithms are mainly inspired from POMDP research (dynamic programming and forward search) and require an inordinate amount of time for even very small DEC-POMDPs. In this thesis, we develop a new mathematical programming based approach for exactly solving a finite horizon DEC-POMDP. We use the sequence form of a control policy in this approach. Using the sequence form, we show how the problem can be formulated as a mathematical progam with a nonlinear object and linear constraints. We thereby show how this nonlinear program can be linearized to a 0-1 mixed integer linear program (MIP). We present two different 0-1 MIPs based on two different properties of a DEC-POMDP. The computational experience of the mathematical programs presented in the thesis on four benchmark problems (MABC, MA-Tiger, Grid Meeting, Fire Fighting) shows that the time taken to find an optimal joint policy is one or two orders or magnitude lesser than the exact existing algorithms. In the problems tested, the time taken drops from several hours to a few seconds or minutes
Ferrari, Fabio Valerio. "Cooperative POMDPs for human-Robot joint activities." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMC257/document.
Full textThis thesis presents a novel method for ensuring cooperation between humans and robots in public spaces, under the constraint of human behavior uncertainty. The thesis introduces a hierarchical and flexible framework based on POMDPs. The framework partitions the overall joint activity into independent planning modules, each dealing with a specific aspect of the joint activity: either ensuring the human-robot cooperation, or proceeding with the task to achieve. The cooperation part can be solved independently from the task and executed as a finite state machine in order to contain online planning effort. In order to do so, we introduce a belief shift function and describe how to use it to transform a POMDP policy into an executable finite state machine.The developed framework has been implemented in a real application scenario as part of the COACHES project. The thesis describes the Escort mission used as testbed application and the details of implementation on the real robots. This scenario has as well been used to carry several experiments and to evaluate our contributions
Brooks, Alex. "Parametric POMDPs for planning in continuous state spaces." University of Sydney, 2007. http://hdl.handle.net/2123/1861.
Full textThis thesis is concerned with planning and acting under uncertainty in partially-observable continuous domains. In particular, it focusses on the problem of mobile robot navigation given a known map. The dominant paradigm for robot localisation is to use Bayesian estimation to maintain a probability distribution over possible robot poses. In contrast, control algorithms often base their decisions on the assumption that a single state, such as the mode of this distribution, is correct. In scenarios involving significant uncertainty, this can lead to serious control errors. It is generally agreed that the reliability of navigation in uncertain environments would be greatly improved by the ability to consider the entire distribution when acting, rather than the single most likely state. The framework adopted in this thesis for modelling navigation problems mathematically is the Partially Observable Markov Decision Process (POMDP). An exact solution to a POMDP problem provides the optimal balance between reward-seeking behaviour and information-seeking behaviour, in the presence of sensor and actuation noise. Unfortunately, previous exact and approximate solution methods have had difficulty scaling to real applications. The contribution of this thesis is the formulation of an approach to planning in the space of continuous parameterised approximations to probability distributions. Theoretical and practical results are presented which show that, when compared with similar methods from the literature, this approach is capable of scaling to larger and more realistic problems. In order to apply the solution algorithm to real-world problems, a number of novel improvements are proposed. Specifically, Monte Carlo methods are employed to estimate distributions over future parameterised beliefs, improving planning accuracy without a loss of efficiency. Conditional independence assumptions are exploited to simplify the problem, reducing computational requirements. Scalability is further increased by focussing computation on likely beliefs, using metric indexing structures for efficient function approximation. Local online planning is incorporated to assist global offline planning, allowing the precision of the latter to be decreased without adversely affecting solution quality. Finally, the algorithm is implemented and demonstrated during real-time control of a mobile robot in a challenging navigation task. We argue that this task is substantially more challenging and realistic than previous problems to which POMDP solution methods have been applied. Results show that POMDP planning, which considers the evolution of the entire probability distribution over robot poses, produces significantly more robust behaviour when compared with a heuristic planner which considers only the most likely states and outcomes.
Brooks, Alex M. "Parametric POMDPs for planning in continuous state spaces." Connect to full text, 2007. http://hdl.handle.net/2123/1861.
Full textTitle from title screen (viewed 15 January 2009). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Australian Centre for Field Robotics, School of Aerospace, Mechanical and Mechatronic Engineering. Includes bibliographical references. Also available in print form.
Atrash, Amin. "A Bayesian Framework for Online Parameter Learning in POMDPs." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104587.
Full textComme le nombre d'agents autonomes et semi-autonomes dansnotre société ne cesse de croître, les prises de décisions sous incertitude constituent désormais un problème critique. Malgré l'incertitude et l'ambiguité inhérentes à leurs environnements, ces agents doivent demeurer robustes dans l'exécution de leurs tâches. Les processus de décision markoviens partiellement observables (POMDP) offrent un cadre mathématique permettant la modélisation des agents et de leurs environnements. Ces modèles sont capables de capturer l'incertitude due aux perturbations dans les capteurs ainsi qu'aux actionneurs imprécis. Ils permettent conséquemment une prise de décision tenant compte des connaissances imparfaites des agents. À ce jour, les POMDP ont été utilisés avec succès dans un éventail de domaines, allant de la robotique à la gestion de dialogue, en passant par la médecine. Plusieurs travaux de recherche se sont penchés sur des méthodes visant à optimiser les POMDP. Cependant, ces méthodes requièrent habituellement un modèle environnemental préalablement connu. Dans ce mémoire, une méthode bayésienne d'apprentissage par renforcement est présentée, avec laquelle il est possible d'apprendre les paramètres du modèle POMDP pendant l'éxécution. Cette méthode tire avantage d'une coopération avec un opérateur capable de guider l'apprentissage en divulguant certaines données optimales. Avec l'aide du renforcement bayésien, l'agent peut apprendre pendant l'éxécution, incorporer immédiatement les données nouvelles et profiter des connaissances précédentes, pour finalement pouvoir adapter sa politique de décision à celle de l'opérateur. La méthodologie décrite est validée à l'aide de données produites par le gestionnaire d'interactions d'une chaise roulante autonome. Ce gestionnaire prend la forme d'une interface intelligente entre le robot et l'usager, permettant à celui-ci de stipuler des commandes de haut niveau de façon naturelle, par exemple en parlant à voix haute. Les fonctions du gestionnaire sont accomplies à l'aide d'un POMDP et constituent un scénario d'apprentissage idéal, dans lequel l'agent doit s'ajuster progressivement aux besoins de l'usager.
Skoglund, Caroline. "Risk-aware Autonomous Driving Using POMDPs and Responsibility-Sensitive Safety." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-300909.
Full textAutonoma fordon förutspås spela en stor roll i framtiden med målen att förbättra effektivitet och säkerhet för vägtransporter. Men även om vi sett flera exempel av autonoma fordon ute på vägarna de senaste åren är frågan om hur säkerhet ska kunna garanteras ett utmanande problem. Det här examensarbetet har studerat denna fråga genom att utveckla ett ramverk för riskmedvetet beslutsfattande. Det autonoma fordonets dynamik och den oförutsägbara omgivningen modelleras med en partiellt observerbar Markov-beslutsprocess (POMDP från engelskans “Partially Observable Markov Decision Process”). Ett riskmått föreslås baserat på ett säkerhetsavstånd förkortat RSS (från engelskans “Responsibility-Sensitive Safety”) som kvantifierar det minsta avståndet till andra fordon för garanterad säkerhet. Riskmåttet integreras i POMDP-modellens belöningsfunktion för att åstadkomma riskmedvetna beteenden. Den föreslagna riskmedvetna POMDP-modellen utvärderas i två fallstudier. I ett scenario där det egna fordonet följer ett annat fordon på en enfilig väg visar vi att det egna fordonet kan undvika en kollision då det framförvarande fordonet bromsar till stillastående. I ett scenario där det egna fordonet ansluter till en huvudled från en ramp visar vi att detta görs med ett tillfredställande avstånd till andra fordon. Slutsatsen är att den riskmedvetna POMDP-modellen lyckas realisera en avvägning mellan säkerhet och användbarhet genom att hålla ett rimligt säkerhetsavstånd och anpassa sig till andra fordons beteenden.
Cohen, Jonathan. "Formation dynamique d'équipes dans les DEC-POMDPS ouverts à base de méthodes Monte-Carlo." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMC225/document.
Full textThis thesis addresses the problem where a team of cooperative and autonomous agents, working in a stochastic and partially observable environment towards solving a complex task, needs toe dynamically modify its structure during the process execution, so as to adapt to the evolution of the task. It is a problem that has been seldom studied in the field of multi-agent planning. However, there are many situations where the team of agents is likely to evolve over time.We are particularly interested in the case where the agents can decide for themselves to leave or join the operational team. Sometimes, using few agents can be for the greater good. Conversely, it can sometimes be useful to call on more agents if the situation gets worse and the skills of some agents turn out to be valuable assets.In order to propose a decision model that can represent those situations, we base upon the decentralized and partially observable Markov decision processes, the standard model for planning under uncertainty in decentralized multi-agent settings. We extend this model to allow agents to enter and exit the system. This is what is called agent openness. We then present two planning algorithms based on the popular Monte-Carlo Tree Search methods. The first algorithm builds separable joint policies by computing series of best responses individual policies, while the second algorithm builds non-separable joint policies by ranking the teams in each situation via an Elo rating system. We evaluate our methods on new benchmarks that allow to highlight some interesting features of open systems
Pokharel, Gaurab. "Increasing the Value of Information During Planning in Uncertain Environments." Oberlin College Honors Theses / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1624976272271825.
Full textTschantz, Michael Carl. "Formalizing and Enforcing Purpose Restrictions." Research Showcase @ CMU, 2012. http://repository.cmu.edu/dissertations/128.
Full textHernandez, Camilo. "Réalisation d’une micropompe à actionnement piézoélectrique." Paris 11, 2010. http://www.theses.fr/2010PA112384.
Full textThe objective of this thesis is to develop a new type of piezoelectric micro-pump with a structure easily adaptable to multiple applications, sizes and operating conditions. This in order to overcome the limitations found in the existing architectures. The principle of the proposed device consists of using a mechanical travelling wave induced on a metallic beam to create motion in a fluid placed above it and enclosed by flexible containers
Rahhal, Charbel. "Conception d’une pompe à chaleur air/eau à haute efficacité énergétique pour la réhabilitation d’installations de chauffage existantes." Paris, ENMP, 2006. http://www.theses.fr/2006ENMP1435.
Full textHeating and domestic hot water production represent more than 80% of the energy consumption of the residential sector in France. The rehabilitation is of great potential. The replacement of old boilers by air-to-water heat pumps constitutes one of the most effective solutions, which leads to a major reduction of greenhouse gas emissions. The constraints limiting the operation of usual heat pumps have been identified. A new concept of air-to-water versatile heat pump (single-stage / 2-stage) has been developed. The principal functions of this new concept are: heating and cooling, operation without additional electric heat supply, production of domestic hot water in summer and in winter, and capacity control by the compression architecture. The principal results obtained are: Compared to a usual heat pump, the new concept allows an energy saving up to 34. 5 % and a reduction of the CO2 emissions up to 24 % depending on the climatic conditions and the hydronic heating distributor system; With the rise of gas and fuel prices, the new concept can compete on total cost conventional solutions for heating with efficient boilers. The CO2 emissions can be reduced by at least a factor 4 compared to fioul or gas-fired boilers. The seasonal COP can be further increased by a better optimisation of both the frosting/defrosting cycles and the combined production of heat and domestic hot water, as well as the replacement of the compressors by more efficient ones
Romet, Philippe. "Intérêt de la normalisation glycémique rapide par infusion insulinique continue dans les neuropathies diabétiques aigues." Montpellier 1, 1990. http://www.theses.fr/1990MON11006.
Full textFolsom-Kovarik, Jeremiah. "Leveraging Help Requests in POMDP Intelligent Tutors." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5210.
Full textPh.D.
Doctorate
Computer Science
Engineering and Computer Science
Computer Science
Png, ShaoWei. "Bayesian reinforcement learning for POMDP-based dialogue systems." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104830.
Full textLes systèmes de dialogues sont de plus en plus populaires depuis l'amélioration des technologies de reconnaissance vocale. Ces systèmes de dialogues peuvent être modélisés efficacement à l'aide des processus de décision markoviens partiellement observables (POMDP). Toutefois, les recherches antérieures supposent généralement une connaissance des paramètres du modèle. L'apprentissage par renforcement basée sur un modèle bayéesien, qui offre un cadre riche pour l'apprentissage et la planification simultanéee, peut éeliminer la néecessitée de cette supposition à cause de la grande complexitée du cadre, le déeveloppement de ces algorithmes pour les systèmes de dialogues complexes repréesente un déefi majeur. Dans ce document, nous déemontrons qu'en exploitant certaines propriéetées connues du système, comme les syméetries, et en utilisant un algorithme de planification approximatif en ligne, nous sommes capables d'appliquer les techniques d'apprentissage par renforcement bayéesien dans le cadre de sur plusieurs domaines de dialogues réealistes. Nous considéerons quelques domaines expéerimentaux. Le premier comprend des donnéees synthéetiques qui servent à illustrer plusieurs propriéetées de notre approche. Le deuxième est un gestionnaire de dialogues basée sur le corpus SACTI1 qui contient 144 dialogues entre 36 utilisateurs et 12 experts. Le troisième gestionnaire aide les patients atteints de déemence à vivre au quotidien. Finalement, nous considéerons un grand gestionnaire de dialogue qui assise des patients à manoeuvrer une chaise roulante automatiséee.
Kaplow, Robert. "Point-based POMDP solvers survey and comparative analysis /." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:8881/R/?func=dbin-jump-full&object_id=92275.
Full textChinaei, Hamid Reza. "Learning Dialogue POMDP Model Components from Expert Dialogues." Thesis, Université Laval, 2013. http://www.theses.ulaval.ca/2013/29690/29690.pdf.
Full textSpoken dialogue systems should realize the user intentions and maintain a natural and efficient dialogue with users. This is however a difficult task as spoken language is naturally ambiguous and uncertain, and further the automatic speech recognition (ASR) output is noisy. In addition, the human user may change his intention during the interaction with the machine. To tackle this difficult task, the partially observable Markov decision process (POMDP) framework has been applied in dialogue systems as a formal framework to represent uncertainty explicitly while supporting automated policy solving. In this context, estimating the dialogue POMDP model components is a signifficant challenge as they have a direct impact on the optimized dialogue POMDP policy. This thesis proposes methods for learning dialogue POMDP model components using noisy and unannotated dialogues. Speciffically, we introduce techniques to learn the set of possible user intentions from dialogues, use them as the dialogue POMDP states, and learn a maximum likelihood POMDP transition model from data. Since it is crucial to reduce the observation state size, we then propose two observation models: the keyword model and the intention model. Using these two models, the number of observations is reduced signifficantly while the POMDP performance remains high particularly in the intention POMDP. In addition to these model components, POMDPs also require a reward function. So, we propose new algorithms for learning the POMDP reward model from dialogues based on inverse reinforcement learning (IRL). In particular, we propose the POMDP-IRL-BT algorithm (BT for belief transition) that works on the belief states available in the dialogues. This algorithm learns the reward model by estimating a belief transition model, similar to MDP (Markov decision process) transition models. Ultimately, we apply the proposed methods on a healthcare domain and learn a dialogue POMDP essentially from real unannotated and noisy dialogues.
Li, Xin. "POMDP compression and decomposition via belief state analysis." HKBU Institutional Repository, 2009. http://repository.hkbu.edu.hk/etd_ra/1012.
Full textToyasaki, Fuminori, Fichtinger Emel Arikan, Lena Silbermayr, and Sigala Ioanna Falagara. "Disaster relief inventory management: horizontal cooperation between humanitarian organizations." Wiley, 2016. http://dx.doi.org/10.1111/poms.12661.
Full textMorlens, Pierre-Albin. "Elévation de l'antigène de cancer CA125 chez les patients traités par pompe à insuline intrapéritonéale." Bordeaux 2, 1997. http://www.theses.fr/1997BOR2P081.
Full textLabidi, Jalel. "La rectification-inverse : modélisation et applications aux thermotransformateurs et thermofrigopompes." Vandoeuvre-les-Nancy, INPL, 1992. http://docnum.univ-lorraine.fr/public/INPL_T_1992_LABIDI_J.pdf.
Full textHänel, Dagmar. "Bestatter im 20. Jahrhundert : zur kulturellen Bedeutung eines tabuisierten Berufs /." Münster : Waxmann, 2003. http://catalogue.bnf.fr/ark:/12148/cb39166301n.
Full textPérez-Martin, Antonia. "Les anticorps anti-insuline sous insulinothérapie péritonéale par système implantable : recherche des déterminants antigéniques et conséquences métaboliques." Montpellier 1, 1997. http://www.theses.fr/1997MON11034.
Full textCamy, Sophie. "La pompe portable externe dans le traitement du diabète insulino-dépendant : bilan du centre d'insulinothérapie au CHU du Haut-Lévêque de 1993 à 1996, perspectives d'avenir." Bordeaux 2, 1998. http://www.theses.fr/1998BOR2P029.
Full textNiang, M'Baye. "Optimisation des procédés de séparation-mélangeage : applications à la distillation fractionnée et aux pompes à chaleur." Vandoeuvre-les-Nancy, INPL, 1995. http://www.theses.fr/1995INPL005N.
Full textDubois, Charlotte. "Identification de mécanismes moléculaires augmentant le potentiel thérapeutique des canaux calciques ORAI et des pompes SERCA." Thesis, Lille 1, 2014. http://www.theses.fr/2014LIL10172.
Full textTumor development requires clearly identified molecular "hallmarks". With regard to prostate cancer, it is well known that it is characterized by a heterogeneous phenotype with a large number of quiescent cells which results in a very slow but aberrant proliferation associated with a resistance to apoptosis induced by chemotherapy. Accordingly, a better understanding of the molecular mechanisms underlying resistance to the phenomenon of apoptosis and deregulation of proliferation is needed. In this context, we have highlighted the key role of ORAI1 and ORAI3 proteins in remodeling of calcium homeostasis involved in the emergence of a more aggressive cancer phenotype. We have discovered the mechanism behind the formation of a channel forming by ORAI1 and ORAI3 proteins permit by : (1) the overexpression of ORAI3 protein and (2) perturbation of the tumor microenvironment during tumor progression. In parallel we studied the mechanisms of action of a very promising new pro-drug undergoing clinical trial, the G-202® (Genspera, USA), which allows the targeting of tumor heterogeneity. We have identified a mechanism of resistance to G-202® alone in vitro and in vivo mouse models (patent pending) and secondly we have developed a new type of combined and target therapies increasing the efficiency of many current chemotherapeutic treatments
Falcoz, Franck. "LASERS CR3+ : LISAF pompés par diodes." Phd thesis, Université Paris Sud - Paris XI, 1996. http://pastel.archives-ouvertes.fr/pastel-00714019.
Full textZheltova, Ludmila. "STRUCTURED MAINTENANCE POLICIES ON INTERIOR SAMPLE PATHS." Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1264627939.
Full textGarcon, Lucile. "Réinventer les pommes et les pommes de terre : une géographie de la qualité à l’épreuve des produits ordinaires." Thesis, Lyon 2, 2015. http://www.theses.fr/2015LYO20050.
Full textIn a context of proliferation of short supply chains, issues of quality invite a shift in geographical focus, moving from specific products characterized by their origin to ordinary products characterized by their provenance. This shift raises the question of the modalities of attachment that these common products have to geographical areas. Everyday foods and common plant materials such as apples and potatoes allow for particular discussion around the issues concerning the reconnection of agriculture and food, specifically around the concept of territorial agri-food systems. Looking at three medium mountain areas - in France (Ardèche, Bauges) and Italy (Liguria) - this thesis proposes an analysis of the trajectories of ten different food collectives through the varying phases of controversy that are driving them towards qualification devices which are more flexible than purely geographical indications. Maintaining the logic of 'rooting', inspired by a territorial rhetoric, the collectives do not fall into the short supply chains model, and maintain, for the most part, the varietal question at the heart of their concerns. This thesis shows that this varietal question can only be treated at the territorial level if we consider the production of food as integrated. That is to say, involving a variety of stakeholders, capable of designing various stages of qualification in the same movement, from plant material management to food consumption. The emergence and realizable qualities of these territorial agri-food systems incite political debate, and raise the question of the public action modalities to promote these devices, which we notice are mainly due to individuals and places of mediation
Memarzadeh, Milad. "System-Level Adaptive Monitoring and Control of Infrastructures: A POMDP-Based Framework." Research Showcase @ CMU, 2015. http://repository.cmu.edu/dissertations/664.
Full textRanger, Pascal-Marie. "La rectification inverse appliquée aux pompes à chaleur à absorption pour valorisation d'effluents thermiques industriels." Vandoeuvre-les-Nancy, INPL, 1993. http://www.theses.fr/1993INPL081N.
Full textPinheiro, Paulo Gurgel 1983. "Planning for mobile robot localization using architectural design features on a hierarchical POMDP approach = Planejamento para localização de robôs móveis utilizando padrões arquitetônicos em um modelo hierárquico de POMDP." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/275601.
Full textTese (doutorado) - Universidade Estadual de Campinas, Instituto de Computação
Made available in DSpace on 2018-08-24T02:06:24Z (GMT). No. of bitstreams: 1 Pinheiro_PauloGurgel_D.pdf: 41476694 bytes, checksum: f3d5b1e2aa32aa6f00ef7ac689a261e2 (MD5) Previous issue date: 2013
Resumo: Localização de robôs móveis é uma das áreas mais exploradas da robótica devido a sua importância para a resolução de problemas, como: navegação, mapeamento e SLAM. Muitos trabalhos apresentaram soluções envolvendo cooperação, comunicação e exploração do ambiente, onde em geral a localização é obtida através de ações randômicas ou puramente orientadas pelo estado de crença. Nesta tese, é apresentado um modelo de planejamento para localização utilizando POMDP e Localização de Markov, que indicaria a melhor ação que o robô deve efetuar em cada momento, com o objetivo de diminuir a quantidade de passos. O foco está principalmente em: i) problemas de difícil localização: onde não há landmark ou informação extra no ambiente que auxilie o robô, ii) situações de performance crítica: onde o robô deve evitar passos randômicos e o gasto de energia e, por último, iii) situações com múltiplas missões. Sabendo que um robô é projetado para desempenhar missões, será proposto, neste trabalho, um modelo onde essas missões são consideradas em paralelo com a localização. Planejar para cenários com múltiplos ambientes é um desafio devido a grande quantidade de estados que deve ser tratada. Para esse tipo de problema, será apresentado um modelo de compressão de mapas que utiliza padrões arquiteturais e de design, como: quantidade de portas, paredes ou área total de um ambiente, para condensar informações que possam ser redundantes. O modelo baseia-se na similaridade das características de desing para agrupar ambientes similares e combiná-los, gerando um único mapa representante que possui uma quantidade de estados menor que a soma total de todos os estados dos ambientes do grupo. Planos em POMDP são gerados apenas para os representantes e não para todo o mapa. Finalmente, será apresentado o modelo hierárquico onde a localização é executada em duas camadas. Na camada superior, o robô utiliza os planos POMDP e os mapas compactos para estimar a grossa estimativa de sua localização e, na camada inferior, utiliza POMDP ou Localização de Markov para a obtenção da postura mais precisa. O modelo hierárquico foi demonstrado com experimentos utilizando o simulador V-REP, e o robô Pioneer 3-DX. Resultados comparativos mostraram que o robô utilizando o modelo proposto, foi capaz de realizar o processo de localização em cenários com múltiplos ambientes e cumprir a missão, mantendo a precisão com uma significativa redução na quantidade de passos efetuados
Abstract: Mobile Robot localization is one of the most explored areas in robotics due to its importance for solving problems, such as navigation, mapping and SLAM. In this work, we are interested in solving global localization problems, where the initial pose of the robot is completely unknown. Several works have proposed solutions for localization focusing on robot cooperation, communication or environment exploration, where the robot's pose is often found by a certain amount of random actions or state belief oriented actions. In order to decrease the total steps performed, we will introduce a model of planning for localization using POMDPs and Markov Localization that indicates the optimal action to be taken by the robot for each decision time. Our focus is on i) hard localization problems, where there are no special landmarks or extra features over the environment to help the robot, ii) critical performance situation, where the robot is required to avoid random actions and the waste of energy roaming over the environment, and iii) multiple missions situations. Aware the robot is designed to perform missions, we have proposed a model that runs missions and the localization process, simultaneously. Also, since the robot can have different missions, the model computes the planning for localization as an offline process, but loading the missions at runtime. Planning for multiple environments is a challenge due to the amount of states we must consider. Thus, we also proposed a solution to compress the original map, creating a smaller topological representation that is easier and cheaper to get plans done. The map compression takes advantage of the similarity of rooms found especially in offices and residential environments. Similar rooms have similar architectural design features that can be shared. To deal with the compressed map, we proposed a hierarchical approach that uses light POMDP plans and the compressed map on the higher layer to find the gross pose, and on the lower layer, decomposed maps to find the precise pose. We have demonstrated the hierarchical approach with the map compression using both V-REP Simulator and a Pioneer 3-DX robot. Comparing to other active localization models, the results show that our approach allowed the robot to perform both localization and the mission in a multiple room environment with a significant reduction on the number of steps while keeping the pose accuracy
Doutorado
Ciência da Computação
Doutor em Ciência da Computação
Bozkurt, Candas. "Pommes: A Tool For Quantitative Project Management." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606030/index.pdf.
Full textTomanari, Gerson Aparecido Yukio. "Manutenção de respostas de observação em pombos." Universidade de São Paulo, 1997. http://www.teses.usp.br/teses/disponiveis/47/47132/tde-06122018-153236/.
Full textThe present investigation assessed the conditioned reinforcing value of stimuli that signal reinforcement (S+) and extinction (S-) in the maintenance of pigeons\' observing responses. In the basic procedure employed in the two experiments of this investigation, food-deprived pigeons were given a series of discrete trials. Half of the trials ended with . response-independent food presentation and half without food presentation; the sequence of food and no-food trials was random. At the beginning of each trial, the single response key available in the operant chamber was illuminated with white light. During the trial, pecking the key could change key color from white to red or green, according to whether the current trial was scheduled to end with food or no food. Thus, pecking the white key functioned as an observing response because it produced signaling stimuli (the red and green key colors). In baseline conditions, pecking the white key produced color change on a variable-interval schedule; once changed, keys remained either red or green until the end of the trial. Baseline and experimental conditions alternated, and the experimental conditions differed in the two experiments: In Experiment 1, red or green presentations were contingent upon 15 or 24 pecks in addition to the variable-interval requirement. Results showed that pigeons\' observing behavior adjusted to the experimental condition requirements so that both key colors were produced. The S- key color was produced more often than the S+ color. In Experiment 2, the variable-interval requirements to produce key-color changes were the same in baseline and experimental conditions. However, in the experimental condition, the duration of each green or red illumination was limited to a maximum of 10 s. The white light resumed after 10 s, and the key-color change could be repeated within the same trial (if the subject again met the variable interval schedule requirement). Results showed that the frequency of re-presentation of the S- color was higher than that of the S+ color. The results of both experiments suggest that S- may function as conditioned reinforcer, at least in the present procedure. These results diverge from the data in the existing literature with pigeons, and they indicate that the variables that control pigeons\' observing responses are only partially known at present. Therefore, current conclusions about the reinforcing value of signaling stimuli should be qualified
Melleu, Fernando Falkenburger. "A imobilidade tônica em pombos (Columba livia)." reponame:Repositório Institucional da UFSC, 2016. https://repositorio.ufsc.br/xmlui/handle/123456789/168137.
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Introdução: A imobilidade tônica (IT) é uma resposta defensiva inata, presente em vertebrados e invertebrados, caracterizada por um estado reversível de profunda inibição comportamental, acompanhada de uma diminuição de responsividade e perda total ou parcial do tônus antigravitacional. A IT é um comportamento conservado em vertebrados, podendo ser observado em diversas espécies de peixes, anfíbios, répteis, aves e mamíferos e nestes animais é desencadeado pela contenção e restrição de movimentos do animal. A IT, portanto, parece ser uma resposta defensiva utilizada como último recurso durante o ataque de predadores. Estudos sobre este fenômeno, realizados principalmente em mamíferos (roedores e lagomorfos) e aves (galiformes) verificaram que a IT é acompanhada de uma série de alterações de variáveis fisiológicas como pressão arterial, frequência cardíaca, temperatura e de níveis plasmáticos de glicocorticóides comparáveis àquelas observadas em outras reações defensivas. Entretanto, esta reação foi pouco estudada do ponto de vista etológico e fisiológico em pombos (C. livia). Mesmo em mamíferos e galiformes, pouco se conhece sobre os circuitos encefálicos, especialmente circuitos mesencefálicos e límbicos, que atuam no controle deste comportamento. Métodos: Neste trabalho descrevemos o comportamento de IT em pombos e realizamos um estudo sobre atributos etológicos da IT, como a sua distribuição em uma coorte e habituação por meio de re-testes. Também foram avaliados parâmetros fisiológicos de temperatura corporal interna e frequência cardíaca (FC) em pombos durante a IT, utilizando aferências através da implantação de sensores telemétricos na cavidade celomática, bem como a avaliação da temperatura corporal externa utilizando termografia por detecção de infravermelho. Utilizando métodos imunoistoquímicos para detecção da proteína c-Fos, verificamos o padrão de ativação neural em diversas regiões mesencefálicas e límbicas de pombos após a indução da IT, ou manipulação em comparação com pombos não-manipulados, e, no hipotálamo, verificamos a ativação de células CRH+ utilizando dupla marcação CRH/c-Fos. Resultados: Durante a IT, pombos apresentaram movimentos palpebrais e movimentos de cabeça que se alteram com o tempo em imobilidade. O comportamento de IT é prevalente na população sendo que apenas 5% dos animais não exibe imobilidade após a contenção. A duração de IT em pombos é alterada quando o teste é repetido por 4 vezes em intervalos de 7 dias ou 24h, entretanto, 4 repetições in tandem parecem aumentar, ainda que de maneira não significante a duração da imobilidade. Tanto a temperatura interna quanto a FC aumentam de maneira significante nos períodos iniciais da IT, porém estes aumentos também podem ser observados em animais apenas manipulados. A temperatura corporal externa diminui em uma relação linear com a duração da IT. A indução da IT promove o aumento da expressão de c-Fos em áreas mesencefálicas: n. intercolicular (lateral e medial), substancia cinzenta periventricular e n. mesencefalico lateral, e límbicas: Arcopallium dorsal, Arcopallium itermédio, região dorsolateral ventral do hipocampo, área septal lateral e do núcleo intersticial da estria terminal. No hipotálamo, tanto a IT quanto a manipulação provocaram um aumento da ativação de células CRH+. Conclusão: A IT é um comportamento prevalente em pombos e não é homogêneo em sua duração. Tanto a IT quanto a manipulação promove respostas fisiológicas de temperatura e FC semelhantes, sugerindo que essas respostas sejam comuns ao estresse em pombos. A indução da IT promove ativação de áreas mesencefálicas comparáveis à região periaqueductal de mamíferos (PAG), também envolvida com comportamentos de defesa. A indução da IT promove a ativação de regiões límbicas no encéfalo do pombo comparáveis a áreas que também estão envolvidas em respostas defensivas em mamíferos, sugerindo que esta resposta é modulada por circuitos prosencefálicos descendentes e que circuitos controlando essa resposta podem ser conservados em amniotas.
Abstract : Introduction: Tonic Immobility (TI) is as innate defensive response, seen in vertebrates and invertebrates, characterized by a reversible state of profound behavioral inhibition, accompanied by a lack of responsiveness ad partial or total loss of antigravitational tonus. TI is a conserved behavior across vertebrates, being observed in several species of fish, amphibians, reptiles, birds and mammals. In these animals, the TI is achieved by restraining the animals movements in a inverted position. Therefore, TI is interpreted as a defensive response utilized as the last resort against predator attacks. Studies about this phenomenon, done especially in mammals (rodents and lagomorphs) and birds (galliforms) showed that TI is accompanied by a series of alterations of physiological variables such as arterial pressure, heart rate, temperature and plasmatic levels of glucocorticoids comparable to those seen in other defensive reactions. Nevertheless, this reaction was studied to a lesser extent, regarding its ethological and physiological features in pigeons (C. livia). Even in mammals and galliform birds, little is known of the encephalic circuitry, especially of the mesencephalic and limbic, that controls this behavior. Methods: In this study we describe the TI behavior in pigeons and its ethological attributes, as well as its distribution in a cohort and its habituation by means of re-testing. Heart rate and core temperature during TI were also evaluated by implanting telemetric sensors into the celomatic cavity of pigeons. External body temperature during TI was evaluated utilizing thermographic detection of infrared. Utilizing immunohistochemical detection of c-Fos we evaluated de pattern of neural activation in mesencephalic and limbic brain regions after TI induction or handling in comparison with non-handled controls, and, in the hypothalamus we assessed the activation of CRH+ cells in the PVN utilizing double-labeling CRH/c-Fos. Results: We found that TI is a prevalent behavior in a cohort of pigeons whereas only 5% of animals failed to become immobile after movement restraint. During TI they presented eyelid and head movements that changed over TI duration. The TI duration in pigeons is not altered after 4 repetitions in intervals of 7 days or 24 hours, however 4 repetitions in tandem seemed to increase (not significantly) the TI duration. Both the core temperature and heart rate showed increases in the beginning of TI of pigeons; however, these increases were not significantly different from those observed after manipulation; We found that the external temperature of pigeons linearly decreases with the duration of tonic immobility. TI induction in pigeons caused an increase in c-Fos expression in mesencephalic areas: intercolicularis (lateral e medial), stratum griseum periventriculares and n. mesencephalicus lateralis, pars dorsalis and limbic areas: dorsal Arcopallium, Arcopallium intermedium, ventral dorsolateral region of the hippocampus, lateral septal area and in the bed nucleus of the stria terminalis. In the hypothalamus, both IT and handling increased de number of activated CRH+ neurons Conclusion: Tonic immobility is a prevalent behavior in pigeons. This behavior is not homogenous. Both TI and manipulation promote physiological responses of temperature and heart rate, suggesting that these responses are common to stress reactions in general and not byproducts of the TI itself. The induction of TI promotes increases in neural activity in mesencephalic regions comparable to the mammalian periaqueductal region (PAG), also implicated in the control of defensive behaviors. The IT induction elicit neuronal activity in limbic regions of the pigeon brain comparable to areas that are also involved with defensive responses in mammals, suggesting that this response is modulated by descending prosencephalic pathways, and that the circuits controlling this response may be highly conserved in amniotes.
FALCOZ, FRANCK. "Lasers cr#3#+ : lisaf pompes par diodes." Paris 11, 1996. http://www.theses.fr/1996PA112190.
Full textTrebinjac, Isabelle. "Contribution théorique et expérimentale à l'analyse de l’écoulement dans une pompe mixte (hélico-centrifuge)." Lyon, INSA, 1985. http://www.theses.fr/1985ISAL0030.
Full textBrunin, Olivier. "Pompe à chaleur a compression-absorption : étude et réalisation expérimentale." Nancy 1, 1995. http://www.theses.fr/1995NAN10426.
Full textSaldaña, Gadea Santiago Jesús. "The effectiveness of social plan sharing in online planning in POMDP-type domains." Winston-Salem, NC : Wake Forest University, 2009. http://dspace.zsr.wfu.edu/jspui/handle/10339/44699.
Full textTitle from electronic thesis title page. Thesis advisor: William H. Turkett Jr. Vita. Includes bibliographical references (p. 47-48).
Hamdad, Ahmed. "Pompe à chaleur sol-eau." Lyon, INSA, 1988. http://www.theses.fr/1988ISAL0080.
Full textFROMAGER, Michael. "Caractérisation et modélisation des lasers solides pompés optiquement." Phd thesis, Université de Caen, 2002. http://tel.archives-ouvertes.fr/tel-00002510.
Full textDruon, Frédéric. "Lasers à impulsions ultra-brèves pompés par diode." Habilitation à diriger des recherches, Université Paris Sud - Paris XI, 2008. http://tel.archives-ouvertes.fr/tel-00504702.
Full textSchultz, Jean-Luc. "Modélisation de la cavitation partielle dans les pompes." Grenoble : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb375938360.
Full textCassou, Thierry. "Optimisation de fonctionnements de pompes à chaleur chimiques." Perpignan, 1993. http://www.theses.fr/1993PERP0168.
Full textMAZIGHI, KHALED. "Lasers a centres colores pompes par diodes lasers." Caen, 1991. http://www.theses.fr/1991CAEN2038.
Full textFromager, Michaël. "Caractérisation et modélisation des lasers solides pompés optiquement." Caen, 2002. http://www.theses.fr/2002CAEN2036.
Full textSchultz, Jean-Luc. "Modélisation de la cavitation partielle dans les pompes." Grenoble INPG, 1988. http://www.theses.fr/1988INPG0012.
Full textSchwarzer, Barbara P. "Pompes à chaleur à absorption multi-étagées pour la production du chaud ou du froid : expérimentation et modélisation de nouvelles structures a film ruisselant de haute performance." Vandoeuvre-les-Nancy, INPL, 1992. http://www.theses.fr/1992INPL071N.
Full textKoch, Lionel. "Rôle des systèmes d’efflux dans la production de biofilm in vitro chez Yersinia pestis." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS577.
Full textPlague is an infectious disease due to Yersinia pestis. This bacterium has caused tens of millions of deaths during three major pandemics. It persists at an endemic state in several areas, as the United States, where it remains under control, and Madagascar, where it is responsible for annual outbreaks. In 2017, a particularly epidemic wave provoked 2,417 casualties, including 209 deaths. However, plague is a zoonosis, circulating in wild rodent populations through fleabites. When a flea feeds on a septicemic animal, the bacteria colonise and block its digestive tract by forming a biofilm. When the host dies, the fleas join a new mammal and transmit the bacteria during their blood meal. Thus the biofilm formation is one of the main plague transmission factors in animal populations but also to humans when they come into contact with infected fleas. We have focused this work on the study of efflux pumps, particularly those belonging to the Resistance-nodulation-division family, which have been described for their role in the formation of biofilm in many other Gram-negative bacteria. To this end, we produced a set of mutants deleted in genes encoding efflux pumps and we measured their ability to produce biofilm. We showed that the deletion of an efflux pump gene decreased the biofilm formation, whereas an opposite effect was observed when several of these genes were deleted. A more detailed study of one of the mutants deleted in tolC coding an outer membrane channel, allowed us to highlight the link between efflux pumps and the ability to produce biofilm. However, we have not been able to isolate a gene or group of genes responsible for promoting or inhibiting biofilm production in Y. pestis
BRAVO, RAISSA ZURLI BITTENCOURT. "THE USE OF UAVS IN HUMANITARIAN RELIEF: A POMDP BASED METHODOLOGY FOR FINDING VICTIMS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=30364@1.
Full textCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
O uso de Veículos Aéreos Não Tripulados (VANTs) na ajuda humanitária tem sido proposto por pesquisadores para localizar vítimas em áreas afetadas por desastres. A urgência desse tipo de operação é encontrar pessoas afetadas o mais rápido possível, o que significa que determinar a roteirização ótima para os VANTs é muito importante para salvar vidas. Como os VANTs tem que percorrer toda a área afetada para encontrar vítimas, a operação de roteirização se torna equivalente a um problema de cobertura. Neste trabalho, uma metodologia para resolver o problema de cobertura é proposta, baseada na heurística do Processo de Decisão de Markov Parcialmente Observável (POMDP), onde as observações feitas pelos VANTs são consideradas. Essa heurística escolhe as ações baseando-se nas informações disponíveis, essas informações são as ações e observações anteriores. A formulação da roteirização do VANT é baseada na ideia de dar prioridades mais altas às áreas mais propensas a terem vítimas. Para aplicar esta técnica em casos reais, foi criada uma metodologia que consiste em quatro etapas. Primeiramente, o problema é modelado em relação à área afetada, tipo de drone que será utilizado, resolução da câmera, altura média do voo, ponto de partida ou decolagem, além do tamanho e prioridade dos estados. Em seguida, a fim de testar a eficiência do algoritmo através de simulações, grupos de vítimas são distribuídos pela área a ser sobrevoada. Então, o algoritmo é iniciado e o drone, a cada iteração, muda de estado de acordo com a heurística POMDP, até percorrer toda a área afetada. Por fim, a eficiência do algoritmo é testada através de quatro estatísticas: distância percorrida, tempo de operação, percentual de cobertura e tempo para encontrar grupos de vítimas. Essa metodologia foi aplicada em dois exemplos ilustrativos: um tornado em Xanxerê, no Brasil, que foi um desastre de início súbito em Abril de 2015, e em um campo de refugiados no Sudão do Sul, um desastre de início lento que começou em 2013. Depois de fazer simulações, foi demonstrado que a solução cobre toda a área afetada por desastres em um período de tempo razoável. A distância percorrida pelo VANT e a duração da operação, que dependem do número de estados, não tiveram um desvio padrão significativo entre as simulações, o que significa que, ainda que existam vários caminhos possíveis devido ao empate das prioridades, o algoritmo tem resultados homogêneos. O tempo para encontrar grupos de vítimas, e portanto o sucesso da operação de resgate, depende da definição das prioridades dos estados, estabelecidas por um especialista. Caso as prioridades sejam mal definidas, o VANT começará a sobrevoar áreas sem vítimas, o que levará ao fracasso da operação de resgate, uma vez que o algoritmo não estará salvando vidas o mais rápido possível. Ainda foi feita uma comparação do algoritmo proposto com o método guloso. A princípio, esse método não cobriu 100 por cento da área afetada, o que tornou a comparação injusta. Para contornar esse problema, o algoritmo guloso foi forçado a percorrer 100 por cento da área afetada e os resultados mostram que o POMDP tem resultados melhores em relação ao tempo para salvar vítimas. Já em relação a distância percorrida e tempo de operação, os resultados são iguais ou melhores para o POMDP. Isso ocorre porque o algoritmo guloso tem o viés de otimizar distância percorrida e, logo, otimiza o tempo de operação. Já o POMDP tem como objetivo, nesta dissertação, salvar vidas e faz isso de forma dinâmica, atualizando sua distribuição de probabilidades a cada observação feita. O ineditismo desta metodologia é ressaltado no capítulo 3, onde mais de 139 trabalhos foram lidos e classificados com o intuito de mostrar quais são as aplicações que drones em logística humanitária, como o POMDP é usado em drones e como a técnica de simulação é utilizada em logística humanitária. Apenas um artigo propõe o u
The use of Unmanned Aerial Vehicles (UAVs) in humanitarian relief has been proposed by researchers for searching victims in disaster affected areas. The urgency of this type of operation is to find the affected people as soon as possible, which means that determining the optimal flight path for UAVs is very important to save lifes. Since the UAVs have to search through the entire affected area to find victims, the path planning operation becomes equivalent to an area coverage problem. In this study, a methodology to solve the coverage problem is proposed, based on a Partially Observable Markov Decision Processes (POMDP) heuristic, which considers the observations made from UAVs. The formulation of the UAV path planning is based on the idea of assigning higher priorities to the areas which are more likely to contain victims. The methodology was applied in two illustrative examples: a tornado in Xanxerê, Brazil, which was a rapid-onset disaster in April 2015 and a refugee s camp in South Sudan, a slow-onset disaster that started in 2013. After simulations, it is demonstrated that this solution achieves full coverage of disaster affected areas in a reasonable time span. The traveled distance and the operation s durations, which are dependent on the number of states, did not have a significative standard deviation between the simulations. It means that even if there were many possible paths, due to the tied priorities, the algorithm has homogeneous results. The time to find groups of victims, and so the success of the search and rescue operation, depends on the specialist s definition of states priorities. A comparison with a greedy algorithm showed that POMDP is faster to find victims while greedy s performance focuses on minimizing the traveled distance. Future research indicates a practical application of the methodology proposed.