Recommender systems learn about our preferences to make targeted suggestions. In this paper we outline a novel game-with-a-purpose designed to infer preferences at scale as a side-effect of gameplay. We evaluate the utility of this data in a recommendation context as part of a small live-user trial.

This paper proposes an online transfer framework to capture the interaction among agents and shows that current transfer learning in reinforcement learning is a special case of online transfer. Furthermore, this paper re-characterizes existing agents-teaching-agents methods as online transfer and analyze one such teaching method in three ways. First, the convergence of Q-learning and Sarsa with tabular representation with a finite budget is proven. Second, the convergence of Q-learning and Sarsa with linear function approximation is established. Third, the we show the asymptotic performance cannot be hurt through teaching. Additionally, all theoretical results are empirically validated.

The Markov Decision Process (MDP) framework is a versatile method for addressing single and multiagent sequential decision making problems. Many exact and approximate solution methods attempt to exploit structure in the problem and are based on value factorization. Especially multiagent settings (MAS), however, are known to suffer from an exponential increase in value component sizes as interactions become denser, meaning that approximation architectures are overly restricted in the problem sizes and types they can handle. We present an approach to mitigate this limitation for certain types of MASs, exploiting a property that can be thought of as "anonymous influence" in the factored MDP. In particular, we show how anonymity can lead to representational and computational efficiencies, both for general variable elimination in a factor graph but also for the approximate linear programming solution to factored MDPs. The latter allows to scale linear programming to factored MDPs that were previously unsolvable. Our results are shown for a disease control domain over a graph with 50 nodes that are each connected with up to 15 neighbors.

This article describes the MultiAgent Decision Process (MADP) toolbox, a software library to support planning and learning for intelligent agents and multiagent systems in uncertain environments. Some of its key features are that it supports partially observable environments and stochastic transition models; has unified support for single- and multiagent systems; provides a large number of models for decision-theoretic decision making, including one-shot decision making (e.g., Bayesian games) and sequential decision making under various assumptions of observability and cooperation, such as Dec-POMDPs and POSGs; provides tools and parsers to quickly prototype new problems; provides an extensive range of planning and learning algorithms for single-and multiagent systems; and is written in C++ and designed to be extensible via the object-oriented paradigm.

We describe our recent work on cost-optimal policy generation, for co-safe linear temporal logic (LTL) specifications that are not satisfiable with probability one in a Markov decision process (MDP) model. We provide an overview of the approach to pose the problem as the optimisation of three standard objectives in a trimmed product MDP. Furthermore, we introduce a new approach for optimising the three objectives, in a decreasing order of priority, based on a “nested” value iteration, where one value table is kept for each objective.

A commitment represents an agent's intention to attempt to bring about some state of the world that is desired by some agent (possibly itself) in the future. Thus, by making a commitment, an agent is agreeing to make sequential decisions that it believes can cause the desired state to arise. In general, though, an agent's actions will have uncertain outcomes, and thus reaching the desired state cannot be guaranteed. For such sequential decision settings with uncertainty, therefore, commitments can only be probabilistic. We argue that standard notions of commitment are insufficient for probabilistic commitments, and propose a new semantics that judges commitment fulfillment not in terms of whether the agent achieved the desired state, but rather in terms of whether the agent made sequential decisions that in expectation would have achieved the desired state with (at least) the promised probability. We have devised various algorithms that operationalize our semantics, to capture problem contexts with probabilistic commitments arising because action outcomes are uncertain, as well as arising because an agent might realize over time that it does not want to fulfill the commitment.

External factors are hard to model using a Markovian state in several real-world planning domains. Although planning can be difficult in such domains, it may be possible to exploit long-term dependencies between states of the environment during planning. We introduce weighted state scenarios to model long-term sequences of states, and we use a model based on a Partially Observable Markov Decision Process to reason about scenarios during planning. Experiments show that our model outperforms other methods for decision making in two real-world domains.

This work presents a general-purpose character reasoning model intended for usage by autonomous team actors that are acting as believable characters (e.g., human team actors fall into this category). The idea is that selecting a cast of believable characters can predetermine a solution to an unexpected challenge that the team may be facing in a rescue mission. This approach in certain cases proves more efficient than an alternative approach based on rational decision making and planning, which ignores the question of character believability. This point is illustrated with a simple numerical example in a virtual world paradigm.

Conventionally, the process of learning the model (exploration) is initialized as either an uninformed or informed policy, where the latter leverages observations to guide future exploration. Informed exploration is ideal as it may allow a model to be learned in fewer samples. However, informed exploration cannot be implemented from the onset when a-priori knowledge on the sensing domain statistics are not available; such policies would only sample the first set of locations, repeatedly. Hence, we present a theoretically-derived bound for transitioning from uninformed exploration to informed exploration for unstructured real-world environments which may be partially-observable and time-varying. This bound is used in tandem with a sparsified Bayesian nonparametric Poisson Exposure Process, which is used to learn to predict the value of information in partiallyobservable and time-varying domains. The result is an uninformed-to-informed exploration policy which outperforms baseline algorithms in real-world data-sets.

Personalized medicine targets the customization of treatment strategies to patients' individual characteristics. Here we consider the problem of optimizing personalized pharmacological treatment strategies for cancer. We focus primarily on developing effective strategies to collect the data necessary for the construction of personalized treatments. We formulate this problem as a contextual bandit and present a new algorithm based on repeated sub-sampling for robust data collection in this framework. We present a case study showing experiments on a simulation setting, built from real data collected in a previous animal experiments. Promising results in this case study have since lead us to deploy this strategy in a partner wet lab to allocate treatments for the next phase of animal experiments.