Planning under uncertainty is an increasingly important research field, and it is clear that the design of robust and scalable algorithms which consider uncertainty is key to the development of effective autonomous and semi-autonomous systems. Partially Observable Markov Decision Processes (POMDPs) offer a powerful mathematical framework for making optimal action choices in noisy and/or uncertain environments. However, integration of the POMDP model with real world applications has been slow due to the high computation cost of exact approaches to POMDP planning. / In recent years, point-based POMDP solvers have emerged as efficient methods for providing approximate solutions by planning over a small subset of the belief space. This thesis first provides a survey on many of the proposed point-based POMDP solvers. We then conduct an empirical analysis on the key components of point-based methods, the belief collection and belief updating processes. This is an important contribution, as previous publications on point-based methods have only compared full algorithms, without comparing the underlying processes. As well, we verify the effect of a variety of parameters and optimizations that could be used within a point-based solver. Experiments are conducted on a variety of POMDP environments. / L'importance grandissante de la recherche dans le domaine de la planification sous incertitude est signe que l'élaboration d'algorithmes robustes et extensibles qui gèrent l'incertitude est un élément clé dans le développement de systèmes autonomes et semi-autonomes efficaces. Les processus de décision markoviens partiellement observables (POMDP) constituent une puissante fondation mathématique pour le choix d'actions optimales dans un environnement incertain. Il a cependant été difficile d'incorporer les POMDPs à des applications réelles, à cause de leur coût de calcul élevé lorsqu'une solution exacte est requise. / Récemment, les approches de résolution de POMDPs dites par points, qui planifient sur un petit sous-ensemble de l'état des croyance, se sont révélées être efficaces pour obtenir des solutions approximatives. Le présent m´emoire propose tout d'abord une revue de plusieurs approches par points. Par la suite, une analyse empirique des composantes primordiales des approches par points, de la collecte d'observations, ainsi que du processus de mise à jour de l'état des croyance, est proposée. De plus, les effets de différents paramètres et optimisations liés aux approches par points sont vérifiés. Des expériences sont conduites avec une variété d'environnements de type POMDP.

Aquest treball proposa una nova arquitectura de control amb coordinació distribuïda per a un robot mòbil (ARMADiCo). La metodologia de coordinació distribuïda consisteix en dos passos: el primer determina quin és l'agent que guanya el recurs basat en el càlcul privat de la utilitat i el segon, com es fa el canvi del recurs per evitar comportaments abruptes del robot.Aquesta arquitectura ha estat concebuda per facilitar la introducció de nous components hardware i software, definint un patró de disseny d'agents que captura les característiques comunes dels agents. Aquest patró ha portat al desenvolupament d'una arquitectura modular dins l'agent que permet la separació dels diferents mètodes utilitzats per aconseguir els objectius, la col·laboració, la competició i la coordinació de recursos.ARMADiCo s'ha provat en un robot Pioneer 2DX de MobileRobots Inc.. S'han fet diversos experiments i els resultats han demostrat que s'han aconseguit les característiques proposades per l'arquitectura. / This work proposes a new mobile robot control architecture with distributed coordination (ARMADiCo). The distributed coordination methodology consists of two steps: the first determines which agent wins the resource based on a private utility computation, and the second how the resource exchange is carried out in order to avoid abrupt robot behaviors. This architecture has been conceived to make easy the introduction of new hardware and software components and an agent design pattern has been defined in order to capture the agents' common features. This pattern has also lead to the development of a modular architecture inside the agent that allows separation of the different methods of achieving goals, collaboration and competition as well as resource coordination.ARMADiCo has been tested on a MobileRobots Inc. Pioneer 2DX robot. Several experiments have been carried out and the results show that the proposed features of the architecture have been accomplished.

Plan recognition is the problem of inferring the goals and plans of an agent after partially observing its behavior. This is the inverse of planning, the problem of finding the actions that need to be done in order to achieve a goal. In this thesis we show how the problem of plan recognition can be solved using unmodified, state-of-the-art planning algorithms and representation languages. Along with a solid computational framework for deriving posterior goal probabilities, we introduce a novel and crisp model-based formulation of plan recognition whose exibility surpasses that of previous approaches. / Plan recognition és un problema computacional que consisteix en identificar el propòsit d'un agent intel.ligent, havent observat parcialment el seu comportament. Aquest és el problema invers al problema de la planificació automàtica, que consisteix en trobar les accions que són necessàries dur a terme per tal d'aconseguir un cert objectiu. En aquesta tesi mostrem com el problema de plan recognition és pot resoldre mitjançant els mateixos algorismes i llenguatges de representació utilitzats per resoldre la planificació automàtica. La nostra proposta no només conté una serie d'algoritmes eficients i robustos, sino que ve suportada per un marc teòric formal, que ofereixen en conjunt una flexibilitat de la qual no disposen propostes prèvies per resoldre plan recognition.

Thesis (PhD)--University of South Australia, 1997

Thesis (M.Eng. in Electronic Engineering)--University of South Australia, 1995.

Thesis (MEng (ElectronSys))--University of South Australia, 2001

Thesis (M.S. - Hydrology and water Resources)--University of Arizona, 1983. / Includes bibliographical references (leaves 77-81).

Thesis (Ph. D. - Hydrology and Water Resources)--University of Arizona, 1984. / Includes bibliographical references (leaves 243-250).

Thesis (M.S. - Hydrology and Water Resources)--University of Arizona, 1986. / Includes bibliographical references (leaves 139-142).

Thesis (M.S. - Hydrology and Water Resources)--University of Arizona, 1985. / Includes bibliographical references (leaves 103-106).