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12
COWL: Contextualizing Ontologies
, 2003
"... Ontologies are shared models of a domain that encode a view which is common to a set of different parties. Contexts are local models that encode a party's subjective view of a domain. In this paper we show how ontologies can be contextualized, thus acquiring certain useful properties that a ..."
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Cited by 240 (31 self)
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Ontologies are shared models of a domain that encode a view which is common to a set of different parties. Contexts are local models that encode a party's subjective view of a domain. In this paper we show how ontologies can be contextualized, thus acquiring certain useful properties that a pure shared approach cannot provide. We say that an ontology is contextualized or, also, that it is a contextual ontology, when its contents are kept local, and therefore not shared with other ontologies, and mapped with the contents of other ontologies via explicit (context) mappings. The result is Context OWL (COWL), a language whose syntax and semantics have been obtained by extending the OWL syntax and semantics to allow for the representation of contextual ontologies.
Drago: Distributed reasoning architecture for the semantic web
 In ESWC
, 2005
"... Abstract. The paper addresses the problem of reasoning with multiple ontologies interrelated with semantic mappings. This problem is becoming more and more relevant due to the necessity of building a scalable ontological reasoning tools for the Semantic Web. In contrast to the so called global appro ..."
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Cited by 78 (9 self)
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Abstract. The paper addresses the problem of reasoning with multiple ontologies interrelated with semantic mappings. This problem is becoming more and more relevant due to the necessity of building a scalable ontological reasoning tools for the Semantic Web. In contrast to the so called global approach, in which reasoning with multiple semantically related ontologies is performed in a global knowledge base that encodes both ontologies and semantic mappings, we propose a distributed reasoning approach in which reasoning is the result of combination via semantic mappings of local reasonings chunks performed in single ontologies. The paper presents a tableaubased distributed reasoning procedure which is sound and complete w.r.t. Distributed Description Logics, the formal framework used to represent multiple semantically connected ontologies. The paper also describes the design and implementation principles of a distributed reasoning system, called DRAGO (Distributed Reasoning Architecture for a Galaxy of Ontology), that implements such distributed decision procedure. 1
Paiva: Constructive CK for Contexts
 Propositional Lax Logic. Information and Computation
, 1997
"... Abstract. This note describes possible world semantics for a constructive modal logic CK. The system CK is weaker than other constructive modal logics K as it does not satisfy distribution of possibility over disjunctions, neither binary (3(A ∨ B) → 3A ∨ 3B) nor nullary (3 ⊥ → ⊥). We are intereste ..."
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Cited by 10 (4 self)
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Abstract. This note describes possible world semantics for a constructive modal logic CK. The system CK is weaker than other constructive modal logics K as it does not satisfy distribution of possibility over disjunctions, neither binary (3(A ∨ B) → 3A ∨ 3B) nor nullary (3 ⊥ → ⊥). We are interested in this version of constructive K for its application to contexts in AI [dP03]. However, our previous work on CK described only a categorical semantics [BdPR01] for the system, while most logicians interested in contexts prefer their semantics possible worlds style. This note fills the gap by providing the possible worlds model theory for the constructive modal system CK, showing soundness and completeness of the proposed semantics, as well as the finite model property and (hence) decidability of the system. Wijesekera [Wij90] investigated possible worlds semantics of a system similar to CK, without the binary distribution, but satisfying the nullary one. The semantics presented here for CK is new and considerably simpler than the one of Wijesekera. 1
Distributed Reasoning Services for Multiple Ontologies
, 2004
"... The main goal of this paper is to propose a distributed paradigm for reasoning with multiple ontologies connected by semantic mappings. The contribution of the paper to this goal is twofold. From the theoretical point of view we characterize the problem of global subsumption (i.e. the problem of ..."
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Cited by 8 (2 self)
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The main goal of this paper is to propose a distributed paradigm for reasoning with multiple ontologies connected by semantic mappings. The contribution of the paper to this goal is twofold. From the theoretical point of view we characterize the problem of global subsumption (i.e. the problem of subsumption in a set of local ontologies connected by semantic mappings) as a suitable fixpoint combination of operators that compute subsumptions in the local ontologies. This allows us to define a sound and complete algorithm for global subsumptions which calls blackboxes subroutines for local subsumptions. The second contribution is the description of a prototype implementation of such algorithm in a peertopeer architecture.
Towards constructive hybrid logic (Extended Abstract)
 IN ELEC. PROC. OF METHODS FOR MODALITIES 3
, 2003
"... ..."
Satisfiability for propositional contexts
 In Proc. of the Principles of Knowledge Representation and Reasoning (KR2004
, 2004
"... We propose a sound and complete satisfiability algorithm for propositional multicontext systems. In essence, the algorithm is a distribution policy built on top of local reasoning procedures, one for each context, which can be implemented by (a diversity of) customized stateoftheart SAT solvers. ..."
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Cited by 6 (5 self)
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We propose a sound and complete satisfiability algorithm for propositional multicontext systems. In essence, the algorithm is a distribution policy built on top of local reasoning procedures, one for each context, which can be implemented by (a diversity of) customized stateoftheart SAT solvers. The foremost intuition that has motivated our algorithm, and the very potential strength of contextual reasoning, is that of keeping reasoning as local as possible. In doing so, we improve on earlier established complexity results by Massacci. Moreover, our approach could be applied to enhance recent proposals by Amir and Mcilraith towards a new partitionbased reasoning paradigm; particularly, our formalism allows for a more expressive description of interpartition relations, and we provide an algorithm that is explicitly designed to deal with this expressiveness.
Updating Contexts
, 2001
"... Different formalisms for contexts have been successfully used to represent and reason about distributed knowledge. In these formalisms, knowledge is represented as a set of contexts, each representing a piece of the whole knowledge. Contexts have been proved particularly adapt to deal with heterogen ..."
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Different formalisms for contexts have been successfully used to represent and reason about distributed knowledge. In these formalisms, knowledge is represented as a set of contexts, each representing a piece of the whole knowledge. Contexts have been proved particularly adapt to deal with heterogeneous distributed knowledge, but, in order to deal with the change of such a knowledge, they must be extended. In particular, they must cope with the problems of adding, deleting, or changing facts in a context, and computing the eect of this change in the other contexts. The current approaches to belief revision and multiagent belief revision can be helpful, but they do not provide a satisfactory treatment of heterogeneity. We provide a formal de nition of the operation of updating a context, and we de ne an algorithm that computes the eects of updating a context on other related contexts. We take a semantic perspective, i.e., each context is formalized as a set of possible partial models of the world.
Multicontext Logic for Semigroups of Contexts
, 2002
"... A multicontext logic with algebraic structure is proposed, where contexts are either primitive or composed from other contexts. Composition of two contexts... ..."
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A multicontext logic with algebraic structure is proposed, where contexts are either primitive or composed from other contexts. Composition of two contexts...
INFORMATION AS CORRELATION VS. INFORMATION AS RANGE: a proposal for identifying and merging two basic logical traditions
"... Information is a ubiquitous term in everyday discourse, but not a particularly welldefined one. And even in scientific discourse, its formal definitions range from Shannon's information theory of bit transmission and channel capacity to Kolmogorov's information theory in terms of shortes ..."
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Information is a ubiquitous term in everyday discourse, but not a particularly welldefined one. And even in scientific discourse, its formal definitions range from Shannon's information theory of bit transmission and channel capacity to Kolmogorov's information theory in terms of shortest algorithmic code driving some universal machine. In addition to these quantitative approaches, there is the great tradition of logic, as the study of meaningful assertions about semantic situations, with deduction or observation as ways of extracting information. 1 There may be one grand unifying mathematical theory lying behind all these perspectives – but 'information ' may also just be a loose family term (cf. van Benthem 2006). Indeed, there is already a striking diversity inside logic itself! One tradition casts information as being encoded in 'state spaces ' that shrink as we learn more. This sense of information, initiated by Rudolf Carnap's Meaning and Necessity, is that of epistemic logic, pioneered by Jaakko Hintikka in 1962. Say, you hand me a sealed letter which contains either a raise or my dismissal. A set of two 'possible worlds' R, D encodes the information available in this scenario, where I do not know my fate. I can change my ignorance to knowledge by opening the envelope, shrinking the set {R, D} to just the actual one. The resulting paradigm of formal languages and logics has also crossed from philosophy into computer science and game theory
Constructive Description Logics:
"... what, why and how Abstract. This note discusses possible conceptions of constructive description logics. We discuss why different communities should be interested in constructive description logics, why so little work has been done on this before and why we think it is important. Our goal is a syste ..."
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what, why and how Abstract. This note discusses possible conceptions of constructive description logics. We discuss why different communities should be interested in constructive description logics, why so little work has been done on this before and why we think it is important. Our goal is a system of constructive contexted description logic, whose contexts are inspired by GuhaMcCarthy’s ideas along the lines of the system described in [BCC+05]. In this note we only lay down the fundamentals of constructive description logics. We describe three systems, produce semantics for them and prove some basic results. 1