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

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

Towards a Practical Implementation of a Reasoner for Inconsistent Possibilistic Description Logic Programming Ontologies

This work reports on our e orts to implement a practical reasoner based on Dung-style argumentation semantics for potentially inconsistent possibilistic ontologies. Our Java-based implementation targets a subset of the description logic programming fragment that we codify in a Racer-like syntax suitably adapted for representing certainty degrees of both axioms and assertions. We introduce our approach with a running example, discuss implementation issues and present time complexity results.Sociedad Argentina de Informática e Investigación Operativa (SADIO

Towards a Practical Implementation of a Reasoner for Inconsistent Possibilistic Description Logic Programming Ontologies

This work reports on our e orts to implement a practical reasoner based on Dung-style argumentation semantics for potentially inconsistent possibilistic ontologies. Our Java-based implementation targets a subset of the description logic programming fragment that we codify in a Racer-like syntax suitably adapted for representing certainty degrees of both axioms and assertions. We introduce our approach with a running example, discuss implementation issues and present time complexity results.Sociedad Argentina de Informática e Investigación Operativa (SADIO

A defeasible logic programming with extra meta-level information through labels

Several argument-based formalisms have emerged with application in many areas, such as legal reasoning, intelligent web search, recommender systems, autonomous agents and multi-agent systems. In decision support systems, autonomous agents need to perform epistemic and practical reasoning; the first requiring reasoning about what to believe, and the latter, involving reasoning about what to do reaching decisions and, often, attaching more information to the pieces of knowledge involved. We will introduce an approach in the framework of DeLP called Argumentative Label Algebra (ALA), incorporating labels as a medium to convey meta-level information; through these labels it will represent different features of interest in the reasoning process, such as strength and weight measures, time availability, degree of reliability, etc. The labels associated with arguments will thus be combined and propagated according to argument interactions. This information can be used for different purposes: to carry information for a specific purpose, to determine which argument defeats another, analyzing a feature that is relevant to the domain, and to define an acceptability threshold which will determine if the arguments are strong enough to be accepted. The aim of this work is to improve the ability of representing real-world scenarios in argumentative systems by modeling different arguments attributes through labels.Varios formalismos basados en argumentos han emergido, con aplicaciones en muchas áreas, tales como el razonamiento legal, la búsqueda inteligente en la web, sistemas de recomendación, agentes autónomos y sistemas multi-agente. En los sistemas de soporte a la decisión, los agentes autónomos necesitan realizar razonamiento epistémico y práctico, el primero requiere razonamiento sobre qué creer, y el ´ultimo involucra razonamiento acerca de qué hacer, frecuentemente, agregando más información a las piezas de conocimiento involucradas. Introduciremos una aproximación en el marco de DeLP denominada Álgebra de Etiqueta para Argumentos (AEA), incorporando etiquetas como un medio para transmitir información de meta-nivel. A través de estas etiquetas se puede representar diferentes rasgos de interés en el proceso de razonamiento, tales como las medidas de peso y fuerza, disponibilidad de tiempo, grados de confiabilidad, etc. Las etiquetas asociadas con los argumentos podrán así ser combinadas y propagadas de acuerdo a las interacciones de los argumentos. Esta información puede ser usada para diferentes propósitos: llevar información para un objetivo específico, determinar cuáles argumentos derrotan a otros, analizar un rasgo que es relevante a un dominio, y definir un umbral de aceptabilidad que determinar´a si un argumento es lo suficientemente fuerte como para ser aceptado. El objetivo de este trabajo es mejorar la habilidad de representar escenarios del mundo real en sistemas argumentativos al modelar diferentes atributos de los argumentos a través de las etiquetas.Fil: Budan, Maximiliano Celmo David. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Sur; Argentina. Universidad Nacional de Santiago del Estero; ArgentinaFil: Gomez Lucero, Mauro Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Sur; ArgentinaFil: Simari, Guillermo Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Sur; Argentin

A Framework for Combining Defeasible Argumentation with Labeled Deduction

In the last years, there has been an increasing demand of a variety of logical systems, prompted mostly by applications of logic in AI and other related areas. Labeled Deductive Systems (LDS) were developed as a flexible methodology to formalize such a kind of complex logical systems. Defeasible argumentation has proven to be a successful approach to formalizing commonsense reasoning, encompassing many other alternative formalisms for defeasible reasoning. Argument-based frameworks share some common notions (such as the concept of argument, defeater, etc.) along with a number of particular features which make it difficult to compare them with each other from a logical viewpoint. This paper introduces LDSar, a LDS for defeasible argumentation in which many important issues concerning defeasible argumentation are captured within a unified logical framework. We also discuss some logical properties and extensions that emerge from the proposed framework.Comment: 15 pages, presented at CMSRA Workshop 2003. Buenos Aires, Argentin