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Rocher Swan - One of the best experts on this subject based on the ideXlab platform.
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Interrogation de bases de connaissances avec règles existentielles : décidabilité et complexité
HAL CCSD, 2016Co-Authors: Rocher SwanAbstract:In this thesis we investigate the issue of querying knowledge bases composed of data and general background knowledge, called an ontology. Ontological knowledge can be represented under different formalisms and we consider here a fragment of first-order logic called existential rules (also known as tuple-generating dependencies and Datalog+/-).The fundamental entailment problem at the core of this thesis asks if a conjunctive query is entailed by an existential rule knowledge base. General existential rules are highly expressive, however at the cost of undecidability. Various restrictions on sets of rules have been proposed to regain the decidability of the entailment problem.Our specific contribution is two-fold. First, we propose a new tool that allows to unify and extend most of the known existential rule classes that rely on acyclicity conditions to tame infinite forward chaining, without increasing the complexity of the acyclicity recognition. Second, we study the compatibility of known decidable rule classes with a frequently required modeling construct, namely Transitivity of binary relations. We help clarifying the picture of negative and positive results on this question, and provide a technique to safely combine Transitivity with one of the simplest, yet useful, decidable rule classes, namely linear rules.Dans cette thèse, nous nous intéressons au problème d'interrogation de bases de connaissances composées de données et d'une ontologie, qui représente des connaissances générales sur le domaine d'application. Parmi les différents formalismes permettant de représenter les connaissances ontologiques, nous considérons ici un fragment de la logique du premier ordre appelé règles existentielles (aussi connues sous le nom de ``tuple generating dependencies'' et Datalog+/-). Le problème fondamental de conséquence logique au cœur de cette thèse demande si une requête conjonctive est conséquence d'une base de connaissances. Les règles existentielles étant très expressives, ce problème est indécidable. Toutefois, différentes restrictions sur les ensembles de règles ont été proposées afin d'obtenir sa décidabilité.La contribution de cette thèse est double. Premièrement, nous proposons un outil qui nous permet d'unifier puis d'étendre la plupart des classes de règles connues reposant sur des notions d'acyclicité assurant la finitude du chaînage avant. Deuxièmement, nous étudions la compatibilité des classes décidables de règles existentielles connues avec un type de connaissance souvent nécessaire dans les ontologies: la transitivité de relations binaires. Nous aidons à clarifier le paysage des résultats positifs et négatifs liés à cette question et fournissons une approche permettant de combiner la transitivité avec les règles existentielles linéaires
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Interrogation de Bases de Connaissances avec Règles Existentielles : Décidabilité et Complexité
HAL CCSD, 2016Co-Authors: Rocher SwanAbstract:In this thesis we investigate the issue of querying knowledge basescomposed of data and general background knowledge, called anontology. Ontological knowledge can be represented under differentformalisms and we consider here a fragment of first-order logiccalled existential rules (also known as tuple-generatingdependencies and Datalog+/-).The fundamental entailment problem at the core of this thesis asks if aconjunctive query is entailed by an existential rule knowledge base.General existential rules are highly expressive, however at the costof undecidability. Various restrictions on sets of rules have beenproposed to regain the decidability of the entailment problem. Ourspecific contribution is two-fold. First, we propose a new tool thatallows to unify and extend most of the known existential ruleclasses that rely on acyclicity conditions to tame infinite forwardchaining, without increasing the complexity of the acyclicityrecognition. Second, we study the compatibility of known decidablerule classes with a frequently required modelling construct, namelyTransitivity of binary relations. We help clarifying the picture ofnegative and positive results on this question, and provide atechnique to safely combine Transitivity with one of the simplest,yet useful, decidable rule classes, namely linear rules.Dans cette thèse, nous nous intéressons au problème d'interrogation debases de connaissances composées de données et d'une ontologie,qui représente des connaissances générales sur le domaine d'application.Parmi les différents formalismes permettant de représenter lesconnaissances ontologiques, nous considérons ici un fragment de lalogique du premier ordre appelé règles existentielles(aussi connues sous le nom de ``tuple generating dependencies'' etDatalog+/-).Le problème fondamental de conséquence logique au coeur de cettethèse demande si une requête conjonctive est conséquence d'une basede connaissances.Les règles existentielles étant très expressives, ce problème est indécidable.Toutefois, différentes restrictions sur les ensembles de règles ont étéproposées afin d'obtenir sa décidabilité.La contribution de cette thèse est double.Premièrement, nous proposons un outil qui nous permet d'unifier puisd'étendre la plupart des classes de règles connues reposant sur desnotions d'acyclicité assurant la finitude du chaînage avant.Deuxièmement, nous étudions la compatibilité des classes décidablesde règles existentielles connues avec un type de connaissance souventnécessaire dans les ontologies: la transitivité de relations binaires.Nous aidons à clarifier le paysage des résultats positifs etnégatifs liés à cette question et fournissons une approchepermettant de combiner la transitivité avec les règles existentielles linéaires
Hidetoshi Shimodaira - One of the best experts on this subject based on the ideXlab platform.
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Joint estimation of non-parametric Transitivity and preferential attachment functions in scientific co-authorship networks
Journal of Informetrics, 2020Co-Authors: Masaaki Inoue, Thong Pham, Hidetoshi ShimodairaAbstract:Abstract We propose a statistical method for estimating the non-parametric Transitivity and preferential attachment functions simultaneously in a growing network, in contrast to conventional methods that either estimate each function in isolation or assume a certain functional form for these. Our model is demonstrated to exhibit a good fit to two real-world co-authorship networks and can illuminate several intriguing details of the preferential attachment and Transitivity phenomena that would be unavailable under traditional methods. Moreover, we introduce a method for quantifying the amount of contributions of these phenomena in the growth process of a network based on the probabilistic dynamic process induced by the model formula. By applying this method, we found that Transitivity dominated preferential attachment in both co-authorship networks. This suggests the importance of indirect relations in scientific creative processes. The proposed method is implemented in the R package FoFaF .
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Joint Estimation of the Non-parametric Transitivity and Preferential Attachment Functions in Scientific Co-authorship Networks.
arXiv: Physics and Society, 2019Co-Authors: Masaaki Inoue, Thong Pham, Hidetoshi ShimodairaAbstract:We propose a statistical method to estimate simultaneously the non-parametric Transitivity and preferential attachment functions in a growing network, in contrast to conventional methods that either estimate each function in isolation or assume some functional form for them. Our model is shown to be a good fit to two real-world co-authorship networks and be able to bring to light intriguing details of the preferential attachment and Transitivity phenomena that would be unavailable under traditional methods. We also introduce a method to quantify the amount of contributions of those phenomena in the growth process of a network based on the probabilistic dynamic process induced by the model formula. Applying this method, we found that Transitivity dominated PA in both co-authorship networks. This suggests the importance of indirect relations in scientific creative processes. The proposed methods are implemented in the R package FoFaF.
Ned Hall - One of the best experts on this subject based on the ideXlab platform.
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causation and the price of Transitivity
The Journal of Philosophy, 2000Co-Authors: Ned HallAbstract:Revisant sa propore critique de la transitivite de la causation, l'A. se propose de resoudre le probleme de l'incompatibilite entre la transitivite et la these de la dependance contrefactuelle par la reconnaissance de differents types de relation causale. Mettant en evidence la structure court-circuitee des contrexemples opposes a la transitivite par D. Lewis, l'A. definit par le terme de changement de position (switch) toute interaction d'un evenement avec une autre structure causale, et en tire les consequences du point de vue de la methodologie et de la metaphysique de la causation.
H Meyer - One of the best experts on this subject based on the ideXlab platform.
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cyclic evaluation of Transitivity of reciprocal relations
Social Choice and Welfare, 2006Co-Authors: B De Baets, H Meyer, B De SchuymerAbstract:A general framework for studying the Transitivity of reciprocal relations is presented. The key feature is the cyclic evaluation of Transitivity: triangles (i.e. any three points) are visited in a cyclic manner. An upper bound function acting upon the ordered weights encountered provides an upper bound for the ‘sum minus 1’ of these weights. Commutative quasi-copulas allow to translate a general definition of fuzzy Transitivity (when applied to reciprocal relations) elegantly into the framework of cycle-Transitivity. Similarly, a general notion of stochastic Transitivity corresponds to a particular class of upper bound functions. Ample attention is given to self-dual upper bound functions.
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Transitivity frameworks for reciprocal relations cycle Transitivity versus fg Transitivity
Fuzzy Sets and Systems, 2005Co-Authors: B De Baets, H MeyerAbstract:For a reciprocal relation Q on a set of alternatives A, two Transitivity frameworks which generalize both T-Transitivity and stochastic Transitivity are compared: the framework of cycle-Transitivity, introduced by the present authors (Soc. Choice Welf., to appear) and which is based upon the ordering of the numbers Q(a,b), Q(b,c) and Q(c,a) for all (a,b,c)@?A^3, and the framework of FG-Transitivity, introduced by Switalski (Fuzzy Sets and Systems 137 (2003) 85) as an immediate generalization of stochastic Transitivity. The rules that enable to express FG-Transitivity in the form of cycle-Transitivity and cycle-Transitivity in the form of FG-Transitivity, illustrate that for reciprocal relations the concept of cycle-Transitivity provides a framework that can cover more types of Transitivity than does the concept of FG-Transitivity.
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On the Cycle-Transitivity of the Dice Model
Theory and Decision, 2003Co-Authors: Bart De Schuymer, Bernard De De Baets, H Meyer, Sándor JeneiAbstract:We introduce the notion of a dice model as a framework for describing a class of probabilistic relations. We investigate the Transitivity of the probabilistic relation generated by a dice model and prove that it is a special type of cycle-Transitivity that is situated between moderate stochastic Transitivity or product-Transitivity on the one side, and Łukasiewicz-Transitivity on the other side. Finally, it is shown that any probabilistic relation with rational elements on a three-dimensional space of alternatives which possesses this particular type of cycle-Transitivity, can be represented by a dice model. The same does not hold in higher dimensions.
Masaaki Inoue - One of the best experts on this subject based on the ideXlab platform.
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Joint estimation of non-parametric Transitivity and preferential attachment functions in scientific co-authorship networks
Journal of Informetrics, 2020Co-Authors: Masaaki Inoue, Thong Pham, Hidetoshi ShimodairaAbstract:Abstract We propose a statistical method for estimating the non-parametric Transitivity and preferential attachment functions simultaneously in a growing network, in contrast to conventional methods that either estimate each function in isolation or assume a certain functional form for these. Our model is demonstrated to exhibit a good fit to two real-world co-authorship networks and can illuminate several intriguing details of the preferential attachment and Transitivity phenomena that would be unavailable under traditional methods. Moreover, we introduce a method for quantifying the amount of contributions of these phenomena in the growth process of a network based on the probabilistic dynamic process induced by the model formula. By applying this method, we found that Transitivity dominated preferential attachment in both co-authorship networks. This suggests the importance of indirect relations in scientific creative processes. The proposed method is implemented in the R package FoFaF .
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Joint Estimation of the Non-parametric Transitivity and Preferential Attachment Functions in Scientific Co-authorship Networks.
arXiv: Physics and Society, 2019Co-Authors: Masaaki Inoue, Thong Pham, Hidetoshi ShimodairaAbstract:We propose a statistical method to estimate simultaneously the non-parametric Transitivity and preferential attachment functions in a growing network, in contrast to conventional methods that either estimate each function in isolation or assume some functional form for them. Our model is shown to be a good fit to two real-world co-authorship networks and be able to bring to light intriguing details of the preferential attachment and Transitivity phenomena that would be unavailable under traditional methods. We also introduce a method to quantify the amount of contributions of those phenomena in the growth process of a network based on the probabilistic dynamic process induced by the model formula. Applying this method, we found that Transitivity dominated PA in both co-authorship networks. This suggests the importance of indirect relations in scientific creative processes. The proposed methods are implemented in the R package FoFaF.
