Comparison Criteria for Argumentation Semantics

Argumentation reasoning is a way for agents to evaluate a situation. Given a framework made of conflicting arguments, a semantics allows to evaluate the acceptability of the arguments. It may happen that the semantics associated to the framework has to be changed. In order to perform the most suitable change, the current and a potential new semantics have to be compared. Notions of difference measures between semantics have already been proposed, and application cases where they have to be minimized when a change of semantics has to be performed, have been highlighted. This paper develops these notions, it proposes an additional kind of difference measure, and shows application cases where measures may have to be maximized, and combined

Looking-ahead in backtracking algorithms for abstract argumentation

We refine implemented backtracking algorithms for a number of problems related to Dung's argumentation frameworks. Under admissible, preferred, complete, stable, semi stable, and ideal semantics we add enhancements, what are so-called global looking-ahead pruning strategies, to the-state-of-the-art implementations of two problems. First, we tackle the extension enumeration problem: constructing some/all set(s) of acceptable arguments of a given argumentation framework. Second, we address the acceptance decision problem: deciding whether an argument is in some/all set(s) of accepted arguments of a given argumentation framework. The experiments that we report show that the speedup gain of the new enhancements is quite significant

dynPARTIX - A Dynamic Programming Reasoner for Abstract Argumentation

The aim of this paper is to announce the release of a novel system for abstract argumentation which is based on decomposition and dynamic programming. We provide first experimental evaluations to show the feasibility of this approach.Comment: The paper appears in the Proceedings of the 19th International Conference on Applications of Declarative Programming and Knowledge Management (INAP 2011

Developing methodology for efficient eelgrass habitat mapping across lidar systems

Super Storm Sandy, the second costliest hurricane in U.S. history, made landfall on the east coast of the U.S. in October 2012. In an attempt to assess the impacts of the storm on coastal ecosystems, several U.S. mapping agencies such as the National Oceanic and Atmospheric Administration (NOAA), the U.S. Geological Survey (USGS), and the U.S. Army Corps of Engineers (USACE) commenced data collection efforts using a variety of remotely-sensed data types including aerial imagery and topobathymetric lidar. The objective of this study was to investigate the applicability of object-based image analysis techniques for benthic habitat mapping. Bathymetry and reflectance data collected by a Riegl VQ-820-G system and the AHAB Chiroptera system along with aerial imagery (Applanix DSS) were compared using an objectbased image analysis (OBIA) technique to classify dense eelgrass beds, mixed sand and macroalgae, and sand habitats. In order to determine the efficacy of this method for benthic habitat classification it was also compared to a manual method of classification from aerial imagery. The resulting habitat maps were compared between systems to determine the feasibility of using one OBIA classification rule set across lidar systems and aerial imagery. Our preliminary results using the Riegl system suggest our methodology correctly classified 85% of benthic habitats. Preliminary results using the Chiroptera also suggests similar accuracy of classification. This methodology will allow streamlined creation of habitat maps for coastal managers and researchers using large sets of data collected by multiple sensors. Testing of this OBIA methodology is ongoing as new data from various sensors becomes available

Recognizing Members of the Tournament Equilibrium Set is NP-hard

A recurring theme in the mathematical social sciences is how to select the "most desirable" elements given a binary dominance relation on a set of alternatives. Schwartz's tournament equilibrium set (TEQ) ranks among the most intriguing, but also among the most enigmatic, tournament solutions that have been proposed so far in this context. Due to its unwieldy recursive definition, little is known about TEQ. In particular, its monotonicity remains an open problem up to date. Yet, if TEQ were to satisfy monotonicity, it would be a very attractive tournament solution concept refining both the Banks set and Dutta's minimal covering set. We show that the problem of deciding whether a given alternative is contained in TEQ is NP-hard.Comment: 9 pages, 3 figure

An Axiomatic Approach to Support in Argumentation

International audienceIn the context of bipolar argumentation (argumentation with two kinds of interaction, attacks and supports), we present an axiomatic approach for taking into account a special interpretation of the support relation, the necessary support. We propose constraints that should be imposed to a bipolar argumentation system using this interpretation. Some of these constraints concern the new attack relations, others concern acceptability. We extend basic Dung’s framework in different ways in order to propose frameworks suitable for encoding these constraints. By the way, we propose a formal study of properties of necessary support