Agents
Optimization of Probabilistic Argumentation with Markov Decision Models
Hadoux, Emmanuel (Université Pierre et Marie Curie (Paris 6)) | Beynier, Aurélie (Université Pierre et Marie Curie (Paris 6)) | Maudet, Nicolas (Université Pierre et Marie Curie (Paris 6)) | Weng, Paul (SYSU-CMU Joint Institute of Engineering, Guangzhou and SYSU-CMU Shunde International Joint Research Institute, Shunde) | Hunter, Anthony (University College London, London)
One prominent way to deal with conflicting view-points among agents is to conduct an argumentative debate: by exchanging arguments, agents can seek to persuade each other. In this paper we investigate the problem, for an agent, of optimizing a sequence of moves to be put forward in a debate, against an opponent assumed to behave stochastically, and equipped with an unknown initial belief state. Despite the prohibitive number of states induced by a naive mapping to Markov models, we show that exploiting several features of such interaction settings allows for optimal resolution in practice, in particular: (1) as debates take place in a public space (or common ground), they can readily be modelled as Mixed Observability Markov Decision Processes, (2) as argumentation problems are highly structured, one can design optimization techniques to prune the initial instance. We report on the experimental evaluation of these techniques.
Reduced Time-Expansion Graphs and Goal Decomposition for Solving Cooperative Path Finding Sub-Optimally
Surynek, Pavel (Charles University in Prague)
Solving cooperative path finding (CPF) by translating it to propositional satisfiability represents a viable option in highly constrained situations. The task in CPF is to relocate agents from their initial positions to given goals in a collision free manner. In this paper, we propose a reduced time expansion that is focused on makespan sub-optimal solving. The suggested reduced time expansion is especially beneficial in conjunction with a goal decomposition where agents are relocated one by one.
Intelligent Agent Supporting Human-Multi-Robot Team Collaboration
Rosenfeld, Ariel (Bar-Ilan University) | Agmon, Noa (Bar-Ilan University) | Maksimov, Oleg (Bar-Ilan University) | Azaria, Amos (Carnegie Mellon University) | Kraus, Sarit (Bar-Ilan University)
The number of multi-robot systems deployed in field applications has risen dramatically over the years. Nevertheless, supervising and operating multiple robots at once is a difficult task for a single operator to execute. In this paper we propose a novel approach for utilizing advising automated agents when assisting an operator to better manage a team of multiple robots in complex environments. We introduce the Myopic Advice Optimization (MYAO) Problem and exemplify its implementation using an agent for the Search And Rescue (SAR) task. Our intelligent advising agent was evaluated through extensive field trials, with 44 non-expert human operators and 10 low-cost mobile robots, in simulation and physical deployment, and showed a significant improvement in both team performance and the operator’s satisfaction.
Toward Estimating Others' Transition Models Under Occlusion for Multi-Robot IRL
Bogert, Kenneth (University of Georgia) | Doshi, Prashant (University of Georgia)
Multi-robot inverse reinforcement learning (mIRL) is broadly useful for learning, from observations, the behaviors of multiple robots executing fixed trajectories and interacting with each other. In this paper, we relax a crucial assumption in IRL to make it better suited for wider robotic applications: we allow the transition functions of other robots to be stochastic and do not assume that the transition error probabilities are known to the learner. Challenged by occlusion where large portions of others' state spaces are fully hidden, we present a new approach that maps stochastic transitions to distributions over features. Then, the underconstrained problem is solved using nonlinear optimization that maximizes entropy to learn the transition function of each robot from occluded observations. Our methods represent significant and first steps toward making mIRL pragmatic.
Deordering and Numeric Macro Actions for Plan Repair
Scala, Enrico (Australian National University) | Torasso, Pietro (Universita')
The paper faces the problem of plan repair in presence of numeric information, by providing a new method for the intelligent selection of numeric macro actions. The method relies on a generalization of deordering, extended with new conditions accounting for dependencies and threats implied by the numeric components. The deordering is used as a means to infer (hopefully) minimal ordering constraints then used to extract independent and informative macro actions. Each macro aims at compactly representing a sub-solution for the overall planning problem. To verify the feasibility of the approach, the paper reports experiments in various domains from the International Planning Competition% measuring the performance of the new strategy using two state of the art numeric planning systems; i.e., Colin Metric-FF. Results show (i) the competitiveness of the strategy in terms of coverage, time and quality of the resulting plans wrt current approaches, and (ii) the actual independence from the planner employed.
Factored Upper Bounds for Multiagent Planning Problems under Uncertainty with Non-Factored Value Functions
Oliehoek, Frans Adriaan (University of Amsterdam and University of Liverpool) | Spaan, Matthijs T. J. (Delft University of Technology) | Witwicki, Stefan John (Swiss Federal Institute of Technology (EPFL))
Nowadays, multiagent planning under uncertainty scales to tens or even hundreds of agents. However, current methods either are restricted to problems with factored value functions, or provide solutions without any guarantees on quality. Methods in the former category typically build on heuristic search using upper bounds on the value function. Unfortunately, no techniques exist to compute such upper bounds for problems with non-factored value functions, which would additionally allow for meaningful benchmarking of methods of the latter category. To mitigate this problem, this paper introduces a family of influence-optimistic upper bounds for factored Dec-POMDPs without factored value functions. We demonstrate how we can achieve firm quality guarantees for problems with hundreds of agents.
A Privacy Preserving Algorithm for Multi-Agent Planning and Search
Brafman, Ronen Israel (Ben Gurion University)
To engage diverse agents in cooperative behavior, it is important, even necessary, to provide algorithms that do not reveal information that is private or proprietary.A number of recent planning algorithms enable agents to plan together for shared goals without disclosing information about their private state and actions. But these algorithms lack clear and formal privacy guarantees: the fact that they do not require agents to explicitly reveal private information, does not imply that such information cannot be deduced. The main contribution of this paper is an enhanced version of the distributed forward-search planning framework of Nissim and Brafman that reveals less information than the original algorithm, and the first, to our knowledge, discussion and formal proof of privacy guarantees for distributed planning and search algorithms.
On the Boundary of (Un)decidability: Decidable Model-Checking for a Fragment of Resource Agent Logic
Alechina, Natasha (University of Nottingham) | Bulling, Nils (Delft University of Technology) | Logan, Brian (University of Nottingham) | Nguyen, Hoang Nga (University of Nottingham)
This choice, which is also related to the finitary and infinitary The model-checking problem for Resource Agent semantics of [Bulling and Farwer, 2010], stipulates whether Logic is known to be undecidable. We review existing in every model, agents always have a choice of doing nothing (un)decidability results and identify a significant (executing an idle action) that produces and consumes fragment of the logic for which model checking no resources [Alechina et al., 2014]. Apart from the technical is decidable. We discuss aspects which makes convenience for model-checking (intuitively it implies model checking decidable and prove undecidability that any strategy to satisfy a next or until formula only needs of two open fragments over a class of models in to ensure the relevant subformula becomes true after finitely which agents always have a choice of doing nothing.
What Do We Elect Committees For? A Voting Committee Model for Multi-Winner Rules
Skowron, Piotr Krzysztof (University of Warsaw)
We present a new model that describes the process of electing a group of representatives (e.g., a parliament) for a group of voters. In this model, called the voting committee model, the elected group of representatives runs a number of ballots to make final decisions regarding various issues. The satisfaction of voters comes from the final decisions made by the elected committee. Our results suggest that depending on a single-winner election system used by the committee to make these final decisions, different multi-winner election rules are most suitable for electing the committee. Furthermore, we show that if we allow not only a committee, but also an election rule used to make final decisions, to depend on the voters' preferences, we can obtain an even better representation of the voters.
Spectrum-Based Fault Localisation for Multi-Agent Systems
Passos, Lúcio S. (University of Porto) | Abreu, Rui (University of Porto) | Rossetti, Rosaldo J. F. (University of Porto)
However, generation of MAS models that SFL is a well-suited technique for MASs. is both error-prone and time intense, as it exponentially Literature has shown that there is no standard similarity increases with the number of agents coefficient that yields the best result for SFL [Yoo et al., 2014; and their interactions. In this paper, we propose Hofer et al., 2015; Le et al., 2013]. Empirical evaluation is a lightweight, automatic debugging-based technique, therefore essential to establish which set of heuristics excels coined ESFL-MAS, which shortens the diagnostic for the specific context to which SFL is being applied. To the process, while only relying on minimal best of our knowledge, SFL has not as yet been applied to information about the system. ESFL-MAS uses a diagnose behavioural faults in MASs; there is hence the need heuristic that quantifies the suspiciousness of an to empirically evaluate different formulae using known faults agent to be faulty; therefore, different heuristics to compare the performance yielded by several coefficients.