An approach to handling inconsistent ontology definitions based on the translation of description logics into defeasible logic programming

The Semantic Web is a future vision of the web where stored information has exact meaning, thus enabling computers to understand and reason on the basis of such information. Assigning semantics to web resources is addressed by means of ontology definitions which are meant to be written in an ontology description language such as OWL-DL that is based on so-called Description Logics (DL). Although ontology definitions expressed in DL can be processed with existing DL reasoners, such DL reasoners are incapable of dealing with inconsistent ontology definitions. Previous research has determined that a subset of DL can be effectively translated into an equivalent subset of logic programming. We propose a method for dealing with inconsistent ontology definitions in the Semantic Web. Our proposal involves mapping DL ontologies into equivalent DeLP programs. That is, given an OWL-DL ontology OOwl, an equivalent DL ontology ODL can be obtained. Provided ODL satisfies certain restrictions, it can be translated into an equivalent DeLP program ODeLP . Therefore, given a query Q w.r.t. OOwl, a dialectical process will be performed to determine if Q is warranted w.r.t. ODeLP .VII Workshop de Agentes y Sistemas Inteligentes (WASI)Red de Universidades con Carreras en Informática (RedUNCI

A preliminary framework for reasoning with inconsistent possibilistic description logics ontologies with disjunctive assertions

We present a preliminary framework for reasoning with possibilistic description logics ontologies with disjunctive assertions (PDLDA ontologies for short). PDLDA ontologies are composed of a terminology as well as an assertional box that allows to declare three kinds of assertional statements: an individual is a member of one concept, two individuals are related through a role, an individual is a member of the union of two or more concepts or two individuals are related through the union of two or more roles. Each axiom in the ontologies has a certainty degree as is usual in possibilistic logics. For reasoning with PDLDA ontologies, we interpret them in terms of a adaptation of Bodanza's Suppositional Argumentation System. Our framework allows to reason with modus ponens and constructive dilemmas. We use it for determining the membership of individuals to concepts when there is doubt to exactly which one of the concepts in the union the individual belongs. We think that our approach will be of use for implementers of reasoning systems in the Semantic Web where uncertainty of membership of individuals to concepts or roles is present.XVI Workshop Agentes y Sistemas Inteligentes (WASI)Red de Universidades con Carreras en Informática (RedUNCI

A preliminary framework for reasoning with inconsistent possibilistic description logics ontologies with disjunctive assertions

We present a preliminary framework for reasoning with possibilistic description logics ontologies with disjunctive assertions (PDLDA ontologies for short). PDLDA ontologies are composed of a terminology as well as an assertional box that allows to declare three kinds of assertional statements: an individual is a member of one concept, two individuals are related through a role, an individual is a member of the union of two or more concepts or two individuals are related through the union of two or more roles. Each axiom in the ontologies has a certainty degree as is usual in possibilistic logics. For reasoning with PDLDA ontologies, we interpret them in terms of a adaptation of Bodanza's Suppositional Argumentation System. Our framework allows to reason with modus ponens and constructive dilemmas. We use it for determining the membership of individuals to concepts when there is doubt to exactly which one of the concepts in the union the individual belongs. We think that our approach will be of use for implementers of reasoning systems in the Semantic Web where uncertainty of membership of individuals to concepts or roles is present.XVI Workshop Agentes y Sistemas Inteligentes (WASI)Red de Universidades con Carreras en Informática (RedUNCI

Reasoning with inconsistent possibilistic description logics ontologies with disjunctive assertions

We present a preliminary framework for reasoning with possibilistic description logics ontologies with disjunctive assertions (PoDLoDA ontologies for short). Given a PoDLoDA ontology, its terminological box is expressed in the description logic programming fragment but its assertional box allows four kinds of statements: an individual is a member of a concept, two individuals are related through a role, an individual is a member of the union of two or more concepts or two individuals are related through the union of two or more roles. Axioms and statements in PoDLoDA ontologies have a numerical certainty degree attached. A disjunctive assertion expresses a doubt respect to the membership of either individuals to union of concepts or pairs of individuals to the union of roles. Because PoDLoDA ontologies allow to represent incomplete and potentially inconsistent information, instance checking is addressed through an adaptation of Bodanza’s Suppositional Argumentation System that allows to reason with modus ponens and constructive dilemmas. We think that our approach will be of use for implementers of reasoning systems in the Semantic Web where uncertainty of membership of individuals to concepts or roles is present.Facultad de Informátic

An approach to handling inconsistent ontology definitions based on the translation of description logics into defeasible logic programming

The Semantic Web is a future vision of the web where stored information has exact meaning, thus enabling computers to understand and reason on the basis of such information. Assigning semantics to web resources is addressed by means of ontology definitions which are meant to be written in an ontology description language such as OWL-DL that is based on so-called Description Logics (DL). Although ontology definitions expressed in DL can be processed with existing DL reasoners, such DL reasoners are incapable of dealing with inconsistent ontology definitions. Previous research has determined that a subset of DL can be effectively translated into an equivalent subset of logic programming. We propose a method for dealing with inconsistent ontology definitions in the Semantic Web. Our proposal involves mapping DL ontologies into equivalent DeLP programs. That is, given an OWL-DL ontology OOwl, an equivalent DL ontology ODL can be obtained. Provided ODL satisfies certain restrictions, it can be translated into an equivalent DeLP program ODeLP . Therefore, given a query Q w.r.t. OOwl, a dialectical process will be performed to determine if Q is warranted w.r.t. ODeLP .VII Workshop de Agentes y Sistemas Inteligentes (WASI)Red de Universidades con Carreras en Informática (RedUNCI

Reasoning with inconsistent possibilistic description logics ontologies with disjunctive assertions

We present a preliminary framework for reasoning with possibilistic description logics ontologies with disjunctive assertions (PoDLoDA ontologies for short). Given a PoDLoDA ontology, its terminological box is expressed in the description logic programming fragment but its assertional box allows four kinds of statements: an individual is a member of a concept, two individuals are related through a role, an individual is a member of the union of two or more concepts or two individuals are related through the union of two or more roles. Axioms and statements in PoDLoDA ontologies have a numerical certainty degree attached. A disjunctive assertion expresses a doubt respect to the membership of either individuals to union of concepts or pairs of individuals to the union of roles. Because PoDLoDA ontologies allow to represent incomplete and potentially inconsistent information, instance checking is addressed through an adaptation of Bodanza’s Suppositional Argumentation System that allows to reason with modus ponens and constructive dilemmas. We think that our approach will be of use for implementers of reasoning systems in the Semantic Web where uncertainty of membership of individuals to concepts or roles is present.Facultad de Informátic

On the Application of Argument Accrual to Reasoning with Inconsistent Possibilistic Ontologies

We present an approach for performing instance checking in a suitable subset of possibilistic description logic programming ontologies by using argument accrual. Ontologies are interpreted in possibilistic logic programming under Dung's grounded semantics. We present a reasoning framework with a case study and a Java-based implementation for enacting the proposed approach.XVII Workshop Agentes y Sistemas Inteligentes (WASI).Red de Universidades con Carreras en Informática (RedUNCI

On the Application of Argument Accrual to Reasoning with Inconsistent Possibilistic Ontologies

We present an approach for performing instance checking in a suitable subset of possibilistic description logic programming ontologies by using argument accrual. Ontologies are interpreted in possibilistic logic programming under Dung's grounded semantics. We present a reasoning framework with a case study and a Java-based implementation for enacting the proposed approach.XVII Workshop Agentes y Sistemas Inteligentes (WASI).Red de Universidades con Carreras en Informática (RedUNCI

Integration of web-based forms with ontologies in the semantic web

La noción de formularios como una manera de organizar y presentar datos ha sido usada desde el comienzo de la World Wide Web. Los formularios web han evolucionado junto con el desarrollo de nuevos lenguajes de marcado, en los cuales es posible proveer guiones de validación como parte del código del formulario para verificar si el significado pretendido del formulario es correcto. Sin embargo, para el diseñador del formulario, parte de este significado pretendido involucra otros atributos que no son restricciones por sí mismas, sino más bien atributos emergentes del formulario, los cuales brindan conclusiones plausibles en el contexto de información incompleta y potencialmente contradictoria. Como el valor de tales atributos puede cambiar en presencia de nuevo conocimiento, los llamamos atributos rebatibles. En trabajos previos, extendimos los formularios web tradicionales para incorporar atributos rebatibles como parte del conocimiento que puede ser codificado por el diseñador del formulario. En este artículo, adaptamos tal acercamiento para hacerlo adecuado para la iniciativa de la Web Semántica; entonces proponemos la especificación de atributos rebatibles por medio de ontologías expresadas en Lógicas para la Descripción posiblemente inconsistentes conocidas como -ontologías. El valor de tales atributos rebatibles sería asociado a la pertenencia de un individuo a un concepto particular. Como las ontologías involucradas en la definición de atributos rebatibles pueden ser inconsistentes, un análisis dialéctico sería realizado para tomar en cuenta todas las razones a favor y en contra del valor del atributo rebatible.The notion of forms as a way of organizing and presenting data has been used since the beginning of the World Wide Web. Web-based forms have evolved together with the development of new markup languages, in which it is possible to provide validation scripts as part of the form code to test whether the intended meaning of the form is correct. However, for the form designer, part of this intended meaning frequently involves other features which are not constraints by themselves, but rather attributes emerging from the form, which provide plausible conclusions in the context of incomplete and potentially inconsistent information. As the value of such attributes may change in presence of new knowledge, we call them defeasible attributes. In previous works, we extended traditional web-based forms to incorporate defeasible attributes as part of the knowledge that can be encoded by the form designer. In this article, we recast that approach to make it suitable for the Semantic Web initiative; we then propose the specification of defeasible attributes by means of possibly inconsistent Description Logics ontologies known as -ontologies. Thus the value of a defeasible attribute will be associated to the membership of an individual to a certain concept. As the ontologies involved in the definition of defeasible attributes may be inconsistent, a dialectical analysis will be performed to take into account all the reasons in favor and against the value of such defeasible attributes.Workshop de Agentes y Sistemas Inteligentes (WASI)Red de Universidades con Carreras en Informática (RedUNCI