Perrussel, Laurent
Discounting in Strategy Logic
Mittelmann, Munyque, Murano, Aniello, Perrussel, Laurent
Discounting is an important dimension in multi-agent systems as long as we want to reason about strategies and time. It is a key aspect in economics as it captures the intuition that the far-away future is not as important as the near future. Traditional verification techniques allow to check whether there is a winning strategy for a group of agents but they do not take into account the fact that satisfying a goal sooner is different from satisfying it after a long wait. In this paper, we augment Strategy Logic with future discounting over a set of discounted functions D, denoted SLdisc[D]. We consider "until" operators with discounting functions: the satisfaction value of a specification in SLdisc[D] is a value in [0, 1], where the longer it takes to fulfill requirements, the smaller the satisfaction value is. We motivate our approach with classical examples from Game Theory and study the complexity of model-checking SLdisc[D]-formulas.
A General Framework for the Logical Representation of Combinatorial Exchange Protocols
Mittelmann, Munyque, Bouveret, Sylvain, Perrussel, Laurent
The goal of this paper is to propose a framework for representing and reasoning about the rules governing a combinatorial exchange. Such a framework is at first interest as long as we want to build up digital marketplaces based on auction, a widely used mechanism for automated transactions. Combinatorial exchange is the most general case of auctions, mixing the double and combinatorial variants: agents bid to trade bundles of goods. Hence the framework should fulfill two requirements: (i) it should enable bidders to express their bids on combinations of goods and (ii) it should allow describing the rules governing some market, namely the legal bids, the allocation and payment rules. To do so, we define a logical language in the spirit of the Game Description Language: the Combinatorial Exchange Description Language is the first language for describing combinatorial exchange in a logical framework. The contribution is two-fold: first, we illustrate the general dimension by representing different kinds of protocols, and second, we show how to reason about auction properties in this machine-processable language.
Refining HTN Methods via Task Insertion with Preferences
Xiao, Zhanhao, Wan, Hai, Zhuo, Hankui Hankz, Herzig, Andreas, Perrussel, Laurent, Chen, Peilin
Hierarchical Task Network (HTN) planning is showing its power in real-world planning. Although domain experts have partial hierarchical domain knowledge, it is time-consuming to specify all HTN methods, leaving them incomplete. On the other hand, traditional HTN learning approaches focus only on declarative goals, omitting the hierarchical domain knowledge. In this paper, we propose a novel learning framework to refine HTN methods via task insertion with completely preserving the original methods. As it is difficult to identify incomplete methods without designating declarative goals for compound tasks, we introduce the notion of prioritized preference to capture the incompleteness possibility of methods. Specifically, the framework first computes the preferred completion profile w.r .t.the prioritized preference to refine the incomplete methods. Then it finds the minimal set of refined methods via a method substitution operation. Experimental analysis demonstrates that our approach is effective, especially in solving new HTN planning instances.
Knowledge Sharing in Coalitions
Jiang, Guifei, Zhang, Dongmo, Perrussel, Laurent
The aim of this paper is to investigate the interplay between knowledge shared by a group of agents and its coalition ability. We investigate this relation in the standard context of imperfect information concurrent game. We assume that whenever a set of agents form a coalition to achieve a goal, they share their knowledge before acting. Based on this assumption, we propose a new semantics for alternating-time temporal logic with imperfect information and perfect recall. It turns out that this semantics is sufficient to preserve all the desirable properties of coalition ability in traditional coalitional logics. Meanwhile, we investigate how knowledge sharing within a group of agents contributes to its coalitional ability through the interplay of epistemic and coalition modalities. This work provides a partial answer to the question: which kind of group knowledge is required for a group to achieve their goals in the context of imperfect information.
Special Track on Uncertain Reasoning
Perrussel, Laurent (University of Toulouse - IRIT) | Butz, Cory (University of Regina, Canada)
Many problems in AI (in reasoning, planning, learning, perception and robotics) require an agent to operate with incomplete or uncertain information. The objective of this track is to present and discuss a broad and diverse range of current work on uncertain reasoning, including theoretical and applied research based on different paradigms. We hope that the variety and richness of this track will help to promote cross fertilization among the different approaches for uncertain reasoning, and in this way foster the development of new ideas and paradigms. The Special Track on Uncertain Reasoning is the oldest track in FLAIRS conferences, running annually since 1996. This meeting will mark the 16th in the series.
Prime Normal Forms in Belief Merging
Marchi, Jerusa (Universidade Federal de Santa Catarina) | Perrussel, Laurent (Institut de Recherche en Informatique de Toulouse)
The aim of Belief Merging is to aggregate possibly conflicting pieces of information issued from different sources. The quality of the resulting set is usually considered in terms of a closeness criterion between the resulting belief set and the initial belief sets. The notion of distance between belief sets is thus a crucial issue when we face the merging problem. The aim of this paper is twofold: introducing a syntactical way to calculate distances and proposing the use of a distance based on prime implicants and prime implicates that considers the importance of each propositional symbol in the belief set.
Dynamic Auction: A Tractable Auction Procedure
Zhang, Dongmo (University of Western Sydney, Australia) | Perrussel, Laurent (University of Toulouse)
Auction processes have been a well-established research Different from one-shot combinatorial auctions, the main theme in economics and recently become an emerging research issue of a dynamic auction is whether the procedure can lead topic in AI due to a set of related computational challenges to an equilibrium state (Walrasian equilibrium) at which all (Cramton et al. 2006). It is well-known that the problem the selling items are effectively allocated to the buyers (equilibrium of winner determination in a combinatorial auction is allocation) and the price of each bundle of items NPcomplete (Rothkopf et al. 1998; Sandholm 2002). However, gives the buyers their best values (equilibrium price). It most of the discussions on the computational issues has been observed that without certain assumptions on buyers' of combinatorial auctions are based on one-shot sealed-bid value functions, there is no guarantee for a dynamic mechanisms. This paper aims to make a contribution towards auction to converge toward an equilibrium (Gul and Stacchetti the discussions on dynamic procedures of combinatorial 1999). Kelso and Crawford (1982) proposed a condition, auctions.
Reasoning about Changes of Corpus of Documents: Reasoning on Association Rules
Perrussel, Laurent (IRIT - Université de Toulouse)
Evaluating changes in documentation of technical products is a key issue in knowledge management. A product may be declined in different versions and one way to evaluate changes is to compare the sets of documents which describe each version. The aim of this paper is to propose a framework for exhibiting changes between sets of documents. This framework is based on the representation of the sets of documents in terms of association rules and on the definition of first order predicates for reasoning with these association rules. The aim of the reasoning stage is to exhibit the differences between the sets of documents. These predicates show what rules are specific to a corpus or how differs the usage of concepts appearing in the associations rules. The framework is experimented with the comparison of two corpuses of documents which describe documentation about two different versions of a spatial component.
Prime Implicants and Belief Update
Perrussel, Laurent (IRIT - Université de Toulouse) | Marchi, Jerusa (DAS - UFSC) | Bittencourt, Guilherme (DAS- UFSC)
In this paper we present a syntactical way to develop the adaptation capability in logical-based intelligent agents. We use prime implicants to represent the beliefs of an agent and present how syntactical belief update operators can be obtained by correlating models and prime implicants. Using prime implicants allows the introdution a new notion of belief update. We characterize this new operator both in terms of postulates and in terms of explicit operators.