1,721,148 research outputs found
Combining boolean games with the power of ontologies for automated multi-attribute negotiation in the Semantic Web
No full textMulti-attribute negotiation has been extensively studied from a game-theoretic viewpoint. In negotiation settings, utility functions are used to express agent preferences. Normal and extensive form games, however, have the drawback of requiring an explicit representation of utility functions, listing the utility values for all combinations of strategies. Therefore, several logical preference languages have been proposed, to specify multi-attribute utility functions in a compact way. Among these approaches, there are also Boolean games. In this paper, we introduce Boolean description logic games, which are a combination of Boolean games with ontological background knowledge, formulated using expressive description logics. In this way, it is possible to enhance the expressiveness of preference representation, maintaining the advantages of the game-theoretic approach. We include and discuss several generalizations, showing their practical usefulness within a service negotiation scenario. Furthermore, we also provide complexity results. © 2009 IEEE
Partially observable game-theoretic agent programming in Golog
Full text linkIn this paper, we present the agent programming language POGTGolog (Partially Observable Game-Theoretic Golog), which integrates explicit agent programming in Golog with game-theoretic multi-agent planning in partially observable stochastic games. In this framework, we assume one team of cooperative agents acting under partial observability, where the agents may also have different initial belief states and not necessarily the same rewards. POGTGolog allows for specifying a partial control program in a high-level logical language, which is then completed by an interpreter in an optimal way. To this end, we define a formal semantics of POGTGolog programs in terms of Nash equilibria, and we then specify a POGTGolog interpreter that computes one of these Nash equilibria
A combination of boolean games with description logics for automated multi-attribute negotiation
No full textMulti-attribute negotiation has been extensively studied from a gametheoretic viewpoint. In negotiation settings, utility functions are used to express agent preferences. Normal and extensive form games, however, have the drawback of requiring an explicit representation of utility functions, listing the utility values for all combinations of strategies. Therefore, several logical preference languages have been proposed, to specify multi-attribute utility functions in a compact way. Among these approaches, there are also Boolean games. In this paper, we introduce Boolean description logic games, which are a combination of Boolean games with ontological background knowledge, formulated using expressive description logics. In this way, it is possible to enhance the expressiveness of preference representation, maintaining the advantages of the game-theoretic approach. We include and discuss several generalizations, showing their practical usefulness within a service negotiation scenario. Furthermore, we also provide complexity results
Temporal Probabilistic Object Bases
No full textThere are numerous applications where we have to deal with temporal uncertainty associated with objects. The ability to automatically store and manipulate time, probabilities, and objects is important. We propose a data model and algebra for temporal probabilistic object bases (TPOBs), which allows us to specify the probability with which an event occurs at a given time point. In explicit TPOB-instances, the sets of time points along with their probability intervals are explicitly enumerated. In implicit TPOB-instances, sets of time points are expressed by constraints and their probability intervals by probability distribution functions. Thus, implicit object base instances are succinct representations of explicit ones; they allow for an efficient implementation of algebraic operations, while their explicit counterparts make defining algebraic operations easy. We extend the relational algebra to both explicit and implicit instances and prove that the operations on implicit instances correctly implement their counterpart on explicit instances
P−SHOQ(D): A Probabilistic Extension of SHOQ(D) for Probabilistic Ontologies in the Semantic Web
No full textOntologies play a central role in the development of the Semantic Web, as they provide precise definitions of shared terms in web resources. One important web ontology language is DAML+OIL; it has a formal semantics and a reasoning support through a mapping to the expressive description logic with the addition of inverse roles. In this paper, we present a probabilistic extension of SHOQ(D), called P-SHOQ(D), to allow for dealing with probabilistic ontologies in the Semantic Web. The description logic P-SHOQ(D) is based on the notion of probabilistic lexicographic entailment from probabilistic default reasoning. It allows to express rich probabilistic knowledge about concepts and instances, as well as default knowledge about concepts. We also present sound and complete reasoning techniques for P-SHOQ(D), which are based on reductions to classical reasoning in SHOQ(D) and to linear programming, and which show in particular that reasoning in P-SHOQ(D) is decidable
Query Answer Explanations under Existential Rules
Full text linkOntology-mediated query answering is an extensively studied paradigm, which aims at improving
query answers with the use of a logical theory. In this paper, we focus on ontology languages based on
existential rules, and we carry out a thorough complexity analysis of the problem of explaining query
answers in terms of minimal subsets of database facts and related task
Reasoning with Semantic-Enabled Qualitative Preferences
No full textPersonalized access to information is an important task in all real-world applications where the user is interested in documents, items, objects or data that match her preferences. Among qualitative approaches to preference representation, CP-nets play a prominent role: with their clear graphical structure, they unify an easy representation of user desires with nice computational properties when computing the best outcome. In this paper, we explore how to reason with CP-nets in the context of the Semantic Web, where preferences are linked to formal ontologies. We show how to compute Pareto optimal outcomes for a semantic-enabled CP-net by solving a constraint satisfaction problem, and we present complexity results related to different ontological language
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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