Modeling time and valuation in structured argumentation frameworks

Temporal Argumentation Frameworks (TAF) represent a recent extension of Dung's abstract argumentation frameworks that consider the temporal availability of arguments. In a TAF, arguments are valid during specific time intervals, called availability intervals, while the attack relation of the framework remains static and permanent in time; thus, in general, when identifying the set of acceptable arguments, the outcome associated with a TAF will vary in time. We introduce an extension of TAF, called Extended Temporal Argumentation Framework (E-TAF), adding the capability of modeling the temporal availability of attacks among arguments, thus modeling special features of arguments varying over time and the possibility that attacks are only available in a given time interval. E-TAF will be enriched by considering Structured Abstract Argumentation, using Dynamic Argumentation Frameworks. The resulting framework, E-TAF∗, provides a suitable model for different time-dependent issues satisfying properties and equivalence results that permit to contrast the expressivity of E-TAF and E-TAF∗ with argumentation based on abstract frameworks. Thus, the main contribution here is to provide an enhanced framework for modeling special features of argumentation varying over time, which are relevant in many real-world situations. The proposal aims at advancing in the integration of time and valuation in the context of argumentation systems as well.Fil: Budan, Maximiliano Celmo David. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación; Argentina. Universidad Nacional de Santiago del Estero. Facultad de Ciencias Exactas y Tecnologías. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; ArgentinaFil: Gomez Lucero, Mauro Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación; ArgentinaFil: Chesñevar, Carlos Iván. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional de Santiago del Estero. Facultad de Ciencias Exactas y Tecnologías. Departamento de Matemática; Argentina. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación; ArgentinaFil: Simari, Guillermo Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación; Argentin

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

Formalization of argument accrual: acceptability semantics and dialectical proof procedure

Argumentation is a powerful paradigm able to formalize commonsense reasoning, finding application in different domains such as automated reasoning, decision making, legal dispute, automated negotiation, etc. However, most of these argumentation-based formalizations do not model the notion of argument accrual, which has been recently gaining importance. This thesis defines a novel formalization of argument accrual, including a declarative characterization of this notion and an associated operational characterization addressing computation. The proposed formalization makes contributions to the existing accrual approaches, mainly concerning the answers obtained, answer explanation, accrual evaluation and comparison, and efficiency of computation.Fil: Gomez Lucero, Mauro Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Sur; Argentin

Modelling argument accrual with possibilistic uncertainty in a logic programming setting

Argumentation frameworks have proven to be a successful approach to formalizing commonsense reasoning. Recently, some argumentation frameworks have emerged which incorporate the treatment of possibilistic uncertainty, notably Possibilistic Defeasible Logic Programming (P-DeLP). At the same time, modelling argument accrual has gained attention from the argumentation community. Even though some preliminary formalizations have been advanced, they do not take into account possibilistic uncertainty when accruing arguments. In this paper we present a novel approach to model argument accrual with possibilistic uncertainty in a constructive way. The formalization proposed uses P-DeLP’s representation language and notion of argument as a basis.Fil: Gomez Lucero, Mauro Javier. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Chesñevar, Carlos Iván. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Simari, Guillermo Ricardo. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin