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24
LocationBased Activity Recognition using Relational Markov Networks
"... In this paper we define a general framework for activity recognition by building upon and extending Relational Markov Networks. Using the example of activity recognition from location data, we show that our model can represent a variety of features including temporal information such as time of day, ..."
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Cited by 144 (14 self)
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In this paper we define a general framework for activity recognition by building upon and extending Relational Markov Networks. Using the example of activity recognition from location data, we show that our model can represent a variety of features including temporal information such as time of day, spatial information extracted from geographic databases, and global constraints such as the number of homes or workplaces of a person. We develop an efficient inference and learning technique based on MCMC. Using GPS location data collected by multiple people we show that the technique can accurately label a person’s activity locations. Furthermore, we show that it is possible to learn good models from less data by using priors extracted from other people’s data.
Logical foundations of negotiation: Strategies and preferences
 In Proceedings of the Ninth International Conference on Principles of Knowledge Representation and Reasoning (KR’04
, 2004
"... This paper is a contribution towards the body of literature which views negotiation in a qualitative light. It builds on an existing logical framework for negotiation between rational, cooperative, truthful agents proposed in (Meyer, Kwok, & Zhang 2003). We show that agents equipped with negotia ..."
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Cited by 25 (6 self)
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This paper is a contribution towards the body of literature which views negotiation in a qualitative light. It builds on an existing logical framework for negotiation between rational, cooperative, truthful agents proposed in (Meyer, Kwok, & Zhang 2003). We show that agents equipped with negotiation strategies corresponding to basic AGM belief revision operations are capable of reaching exactly the permissible deals defined and discussed in (Meyer, Kwok, & Zhang 2003). Each agent has to present a set of weakened demands to the other party who, in return, is obliged to accept all weakened demands. The acceptance of demands is modelled by basic AGM belief revision. We extend the logical framework of (Meyer, Kwok, & Zhang 2003) by considering scenarios in which the initial demand sets of agents may vary. We show that it forces agents to limit their negotiation strategies to AGM belief revision satisfying the supplementary AGM postulates. This leads to the redefinition of a negotiation strategy as a preference relation on demands. This extended framework provides a description of the deals that an agent ought to consider as reasonable, but provides no information on how it should go about choosing a particular deal. We conclude with suggestions on how negotiation strategies can be used to do so.
Logical foundations of negotiation: Outcome, concession and adaptation
 In Proceedings of AAAI’04
"... Most theoretical investigations of the process of negotiation between agents have, thus far, been quantitative in nature. This paper is a contribution towards the body of literature which views negotiation in a qualititative light. Our aim is to provide a logical framework for describing a process o ..."
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Cited by 22 (2 self)
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Most theoretical investigations of the process of negotiation between agents have, thus far, been quantitative in nature. This paper is a contribution towards the body of literature which views negotiation in a qualititative light. Our aim is to provide a logical framework for describing a process of negotiation between agents. We assume that agents are rational, cooperative and truthful. Based on this we provide a characterisation of the rational outcomes of a process of negotiation in terms of a set of rationality postulates, as well as a method for constructing exactly the rational outcomes. The framework is extended by describing two modes of negotiation from which an outcome can be reached. In the concessionary mode, agents are required to weaken their demands in order to accommodate the demands of 1 others. The outcome of such a concessionary process is obtained by combining the (weakened) demands of all agents. In the adaptationist mode, agents are required to adapt to the demands of other in some appropriate fashion. In this case, the outcome consists of the adapted demands that all agents have in common. Both concession and adaptation are alos characterised in terms of rationality postulates. We also provide methods for constructing exactly the rational concessions, as well as the rational adaptations. The central result of the paper is the observation that the outcomes obtained from the concessionary and adaptationist modes both correspond exactly to the rational outcomes. We conclude by pointing out the links between negotiation and AGM belief change, and providing a glimpse of how this may be used to define a notion of preferencebased negotiation. 1
A computational model of logicbased negotiation
 In Proceedings of the 21st National Conference on Artificial Intelligence (AAAI06
, 2006
"... This paper presents a computational model of negotiation based on Nebel’s syntaxbased belief revision. The model guarantees a unique bargaining solution for each bargaining game without using lotteries. Its gametheoretic properties are discussed against the existence and uniqueness of Nash equilib ..."
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Cited by 19 (4 self)
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This paper presents a computational model of negotiation based on Nebel’s syntaxbased belief revision. The model guarantees a unique bargaining solution for each bargaining game without using lotteries. Its gametheoretic properties are discussed against the existence and uniqueness of Nash equilibrium and subgame perfect equilibrium. We also study essential computational properties in relation to our negotiation model. In particular, we show that the deal membership checking is DPcomplete and the corresponding agreement inference problem is ΠP2hard.
Properties of iterated multiple belief revision
 In 7th International Conference on Logic Programming and Nonmonotonic Reasoning (LPNMR
, 2004
"... Abstract. In this paper we investigate the properties of iterated multiple belief revision. We examine several typical assumptions for iterated revision operations with an ontology where an agent assigns ordinals to beliefs, representing strength or firmness of beliefs. A notion of minimal change is ..."
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Cited by 10 (2 self)
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Abstract. In this paper we investigate the properties of iterated multiple belief revision. We examine several typical assumptions for iterated revision operations with an ontology where an agent assigns ordinals to beliefs, representing strength or firmness of beliefs. A notion of minimal change is introduced to express the idea that if no evidence to show how a belief set should be reordered after it is revised, the changes on the ordering should be minimal. It has been shown that under the assumption of minimal change, the multiple version of Darwiche and Pearl’s postulate (C1) holds no matter in what degree new information is accepted. Moreover, under the same assumption, Boutilier’s postulate (CB) holds if and only if new information is always accepted in the lowest degree of firmness while Nayak et al.’s postulate (CN) holds if and only if new information is always accepted in the highest degree. These results provide an ontological base for analyzing the rationality of postulates of iterated belief revision.
Dynamics of Beliefs
"... Abstract. The dynamics of beliefs is one of the major components of any autonomous system, that should be able to incorporate new pieces of information. In this paper we give a quick overview of the main operators for belief change, in particular revision, update, and merging, when the beliefs are r ..."
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Cited by 4 (0 self)
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Abstract. The dynamics of beliefs is one of the major components of any autonomous system, that should be able to incorporate new pieces of information. In this paper we give a quick overview of the main operators for belief change, in particular revision, update, and merging, when the beliefs are represented in propositional logic. And we discuss some works on belief change in more expressive frameworks. 1
Confluence Operators
"... Abstract. In the logic based framework of knowledge representation and reasoning many operators have been defined in order to capture different kinds of change: revision, update, merging and many others. There are close links between revision, update, and merging. Merging operators can be considered ..."
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Cited by 3 (3 self)
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Abstract. In the logic based framework of knowledge representation and reasoning many operators have been defined in order to capture different kinds of change: revision, update, merging and many others. There are close links between revision, update, and merging. Merging operators can be considered as extensions of revision operators to multiple belief bases. And update operators can be considered as pointwise revision, looking at each model of the base, instead of taking the base as a whole. Thus, a natural question is the following one: Are there natural operators that are pointwise merging, just as update are pointwise revision? The goal of this work is to give a positive answer to this question. In order to do that, we introduce a new class of operators: the confluence operators. These new operators can be useful in modelling negotiation processes. 1
An ordinal bargaining solution with fixedpoint property
 Journal of Artificial Intelligence Research
"... Shapley’s impossibility result indicates that the twoperson bargaining problem has no nontrivial ordinal solution with the traditional gametheoretic bargaining model. Although the result is no longer true for bargaining problems with more than two agents, none of the well known bargaining solutio ..."
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Cited by 3 (1 self)
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Shapley’s impossibility result indicates that the twoperson bargaining problem has no nontrivial ordinal solution with the traditional gametheoretic bargaining model. Although the result is no longer true for bargaining problems with more than two agents, none of the well known bargaining solutions are ordinal. Searching for meaningful ordinal solutions, especially for the bilateral bargaining problem, has been a challenging issue in bargaining theory for more than three decades. This paper proposes a logicbased ordinal solution to the bilateral bargaining problem. We argue that if a bargaining problem is modeled in terms of the logical relation of players ’ physical negotiation items, a meaningful bargaining solution can be constructed based on the ordinal structure of bargainers ’ preferences. We represent bargainers ’ demands in propositional logic and bargainers ’ preferences over their demands in total preorder. We show that the solution satisfies most desirable logical properties, such as individual rationality (logical version), consistency, collective rationality as well as a few typical gametheoretic properties, such as weak Pareto optimality and contraction invariance. In addition, if all players ’ demand sets are logically closed, the solution satisfies a fixedpoint condition, which says that the outcome of a negotiation is the result of mutual belief revision. Finally, we define various decision problems in relation to our bargaining model and study their computational complexity. 1.
Logical Properties of BeliefRevisionBased Bargaining Solution ⋆
"... Abstract. This paper explores logical properties of beliefrevisionbased bargaining solution. We first present a syntaxindependent construction of bargaining solution based on prioritized belief revision. With the construction, the computation of bargaining solution can be converted to the calcula ..."
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Abstract. This paper explores logical properties of beliefrevisionbased bargaining solution. We first present a syntaxindependent construction of bargaining solution based on prioritized belief revision. With the construction, the computation of bargaining solution can be converted to the calculation of maximal consistent hierarchy of prioritized belief sets. We prove that the syntaxindependent solution of bargaining satisfies a set of desired logical properties for agreement function and negotiation function. Finally we show that the computational complexity of beliefrevisionbased bargaining can be reduced to Δ P 2 [O(log n)].