Fusion de bases propositionnelles : une méthode basée sur les R-ensembles

La prise de décision collective conduit à l'interaction de plusieurs agents afin d'élaborer une décision commune cohérente. D'un point de vue informatique, ce problème peut se ramener à celui de la fusion de différentes sources d'informations. Dans le domaine de la représentation des connaissances pour l'intelligence artificielle, plusieurs approches ont été proposées pour la fusion de bases de croyances propositionnelles, cependant, la plupart d'entre elles l'ont été sur un plan sémantique et sont peu utilisables en pratique. Ce papier propose une nouvelle approche syntaxique pour la fusion de bases de croyances, appelée Fusion par Rensembles (ou RSF). La notion de R-ensemble, initialement définie dans le contexte de la révision de croyances, est étendue à la fusion et la plupart des opérations classiques de fusion sont capturées syntaxiquement par RSF. Afin d'implanter efficacement RSF, ce papier montre comment RSF peut être codé en un programme logique avec sémantique des modèles stables, puis présente une adaptation du système Smodels permettant de calculer efficacement les R-ensembles. Finalement, une étude expérimentale préliminaire montre que la mise en œuvre utilisant la programmation logique avec sémantique des modèles stables semble prometteuse pour réaliser la fusion de bases de croyances sur des applications réelles. Collective decision making leads to interaction between agents in order to elaborate a consistent common decision. From a data-processing point of view, this problem can be brought back to the merging of different sources of information. In knowledge representation for artificial intelligence, several approaches have been proposed for propositional bases fusion, however, most of them are de- paper proposes a new syntactic approach of belief bases fusion, called Removed Sets Fusion (RSF). The notion of removed-set, initially defined in the context of belief revision is extended to fusion and most of the classical fusion operations are syntactically captured by RSF. In order to efficiently implement RSF, the paper shows how RSF can be encoded into a logic program with answer set semantics, then presents an adaptation of the smodels system devoted to efficiently compute the removed sets in order to perform RSF. Finally a preliminary experimental study shows that the answer set programming approach seems promising for performing belief bases fusion on real scale applications

A Semantic Characterization for ASP Base Revision

International audienceThe paper deals with base revision for Answer Set Programming (ASP). Base revision in classical logic is done by the removal of formulas. Exploiting the non-monotonicity of ASP allows one to propose other revision strategies, namely addition strategy or removal and/or addition strategy. These strategies allow one to define families of rule-based revision operators. The paper presents a semantic characterization of these families of revision operators in terms of answer sets. This semantic characterization allows for equivalently considering the evolution of syntactic logic programs and the evolution of their semantic content. It then studies the logical properties of the proposed operators and gives complexity results

Computing Query Answering With Non-Monotonic Rules: A Case Study of Archaeology Qualitative Spatial Reasoning

International audienceThis paper deals with querying ontology-based knowledge bases equipped with non-monotonic rules through a case study within the framework of Cultural Heritage. It focuses on 3D underwater surveys on the Xlendi wreck which is represented by an OWL2 knowledge base with a large dataset. The paper aims at improving the interactions between the archaeologists and the knowledge base providing new queries that involve non-monotonic rules in order to perform qualitative spatial reasoning. To this end, the knowledge base initially represented in OWL2-QL is translated into an equivalent Answer Set Programming (ASP) program and is enriched with a set of non-monotonic ASP rules suitable to express default and exceptions. An ASP query answering approach is proposed and implemented. Furthermore due to the increased expressiveness of non-monotonic rules it provides spatial reasoning and spatial relations between artifacts query answering which is not possible with query answering languages such as SPARQL and SQWRL

Reproducibility of preclinical animal research improves with heterogeneity of study samples

Single-laboratory studies conducted under highly standardized conditions are the gold standard in preclinical animal research. Using simulations based on 440 preclinical studies across 13 different interventions in animal models of stroke, myocardial infarction, and breast cancer, we compared the accuracy of effect size estimates between single-laboratory and multi-laboratory study designs. Single-laboratory studies generally failed to predict effect size accurately, and larger sample sizes rendered effect size estimates even less accurate. By contrast, multi-laboratory designs including as few as 2 to 4 laboratories increased coverage probability by up to 42 percentage points without a need for larger sample sizes. These findings demonstrate that within-study standardization is a major cause of poor reproducibility. More representative study samples are required to improve the external validity and reproducibility of preclinical animal research and to prevent wasting animals and resources for inconclusive research

Révision par r-ensembles de bases de connaissances en DL-LiteR

National audienceCet article étudie la révision par "r-ensembles" de bases de connaissances exprimées en DL-Lite en présence d'une nouvelle information plus fiable, appelée "entrée". Cette stratégie de révision repose sur la minimisation de l'incohérence. Nous considérons différentes formes d'entrée : une assertion d'appartenance ou un axiome d'inclusion positif ou négatif. Nous donnons les propriétés logiques des opérateurs de révision proposés en termes de postulats. Nous montrons enfin comment utiliser la notion d'échantillon ("hitting sets") pour calculer les r-ensembles. En particulier, nous montrons que pour certaines stratégies de révision et certains types d'entrées la révision par rensembles peut être réalisée en temps polynomial

Changement de croyances et ASP

National audienceno abstrac

An anytime revision operator for large spatial datasets

International audienceno abstrac

Révision de connaissances géographiques

AIX-MARSEILLE1-BU Sci.St Charles (130552104) / SudocSudocFranceF

Un nouveau cadre pour la révision locale de croyances

electronic version (12 pp.)National audienc

A New Model for Belief Representation and Belief Revision Based on Inconsistencies Locality

International audienc