Memory Bounded Open-Loop Planning in Large POMDPs using Thompson Sampling

State-of-the-art approaches to partially observable planning like POMCP are based on stochastic tree search. While these approaches are computationally efficient, they may still construct search trees of considerable size, which could limit the performance due to restricted memory resources. In this paper, we propose Partially Observable Stacked Thompson Sampling (POSTS), a memory bounded approach to open-loop planning in large POMDPs, which optimizes a fixed size stack of Thompson Sampling bandits. We empirically evaluate POSTS in four large benchmark problems and compare its performance with different tree-based approaches. We show that POSTS achieves competitive performance compared to tree-based open-loop planning and offers a performance-memory tradeoff, making it suitable for partially observable planning with highly restricted computational and memory resources.Comment: Presented at AAAI 201

Statistical Analysis and Stochastic Modelling of Foraging Bumblebees.

PhDIn the analysis of movement patterns of animals, stochastic processes play an important role, providing us with a variety of tools to examine, model and simulate their behaviour. In this thesis we focus on the foraging of specific animals - bumblebees - and analyse experimental data to understand the influence of changes in the bumblebees’ environment on their search flights. Starting with a discussion of main classes of stochastic models useful for the description of foraging animals, we then look at a multitude of environmental factors influencing the dynamics of animals in their search for food. With this background we examine flight data of foraging bumblebees obtained from a laboratory experiment by stochastic analyses. The main point of interest of this analysis is the description, modelling and understanding of the data with respect to the influence of predatory threats on the bumblebee’s foraging search flights. After this detail-oriented view on interactions of bumblebees with food sources and predators in the experimental data, we develop a generalized reorientation model. By extracting the necessary information from the data, we arrive at a generalized correlated random walk foraging model for bumblebee flights, which we discuss and compare to the experimental data via simulations. We finish with a discussion of anomalous fluctuation relations and some results on spectral densities of autocorrelation functions. While this part is not directly related to the analysis of foraging, it concerns a closely related class of stochastic processes described by Langevin equations with non- trivial autocorrelation functions analyse experimental data to understand the influence of changes in the bumblebees’ environment on their search flights. Starting with a discussion of main classes of stochastic models useful for the description of foraging animals, we then look at a multitude of environmental factors influencing the dynamics of animals in their search for food. With this background we examine flight data of foraging bumblebees obtained from a laboratory experiment by stochastic analyses. The main point of interest of this analysis is the description, modelling and understanding of the data with respect to the influence of predatory threats on the bumblebee’s foraging search flights. After this detail-oriented view on interactions of bumblebees with food sources and predators in the experimental data, we develop a generalized reorientation model. By extracting the necessary information from the data, we arrive at a generalized correlated random walk foraging model for bumblebee flights, which we discuss and compare to the experimental data via simulations. We finish with a discussion of anomalous fluctuation relations and some results on spectral densities of autocorrelation functions. While this part is not directly related to the analysis of foraging, it concerns a closely related class of stochastic processes described by Langevin equations with nontrivial autocorrelation functions

Research skills training for child psychiatry residents

International audienc

Chatten kann jede/r ;-). Integration von informellen Lern- und Kommunikationswegen und Social Software in ein Blended-Learning-Konzept für Lehramtsstudierende im Bereich Englische Kulturwissenschaft

Das ELAN (E-Learning Academic Network Niedersachsen) III Projekt CELEB (Content-Entwicklung für die Lehrerbildung im Bereich Englische Kultur und Fachdidaktik unter besonderer Berücksichtigung interaktiv-multimedialer Mehrwerte) zielt auf eine Verbesserung der Lehrqualität durch Ergänzung/ Verschränkung der Präsenzlehre mit zielgruppenspezifischen E-Learning-Modulen ab. Entlastung stark frequentierter obligatorischer Einführungsveranstaltungen, Bündelung der fachwissenschaftlichen Expertise der beteiligten Universitäten und zeit- und ortsunabhängiger Zugang zu den Lernressourcen für Studierende sind weitere Ziele des Projektes. Authentizität und Aktualität erhalten die Inhalte durch multimediale Elemente, kollaborative Wissensgenerierung und Interaktivität. Die Universität Hildesheim bietet im Bereich Cultural Studies nach diesem Blended-Learning-Konzept zwei Kurse an, die ständig ausgebaut und erweitert werden. In beiden Kursen kommt Social Software zum Einsatz, da großer Wert auf kollaborativen Wissenserwerb gelegt wird. Informelle Lern- und Kommunikationswege sollen in diesen Kursen Einbettung in formelle Anerkennungsstrukturen finden. (DIPF/ Orig.

Avertissement : [Ankündigung einer neuen Aufl. der "Vaterländischen Predigten über die Sonn- und Festtags-Evangelien"]

http://tartu.ester.ee/record=b2171546~S1*es

Bekanntmachung

http://tartu.ester.ee/record=b2420769~S1*es