How to Choose Weightings to Avoid Collisions in a Restricted Penalty Logic

International audiencePenalty Logic is a natural and commonsense Knowl- edge Representation technique to deal with potentially inconsistent beliefs. Penalty Logic allows some kind of compensation between different pieces of information. But one of the main and less studied flaws of Penalty Logic is the influence of the choice of weights on in- ference: the same pieces of information can provide ex- tremely different results just by changing some weights. This paper concentrates on weightings and on the prob- lem of collisions between interpretations which yield weak conclusions. It focuses more particularly on a family of weightings, the σ -weightings. We show that some of these weightings avoid collisions but that in the meanwhile they disable the mechanism of compensa- tion (and so the interest) of Penalty Logic. We establish then that two of them are suitable for avoiding collisions and maintaining compensation. We obtain their logical characterizations while considering the weightings only and not the associated formulas. Finally, we propose an original weighting, the Paralex Weighting, that improves even more the previous weightings

An Analysis of Sum-Based Incommensurable Belief Base Merging

International audienceDifferent methods have been proposed for merging multiple and potentially conflicting informations. Sum-based operators offer a natural method for merging commensurable prioritized belief bases. Their popularity is due to the fact that they satisfy the majority property and they adopt a non cautious attitude in deriving plausible conclusions. This paper analyses the sum-based merging operator when sources to merge are incommensurable, namely they do not share the same meaning of uncertainty scales. We first show that the obtained merging operator can be equivalently characterized either in terms of an infinite set of compatible scales, or by a well-known Pareto ordering on a set of models. We then study different families of compatible scales useful for merging process. This paper also provides a postulates-based analysis of our merging operators

Dynamics of Natural Killer cell receptor revealed by quantitative analysis of photoswitchable protein

Natural Killer (NK) cell activation is dynamically regulated by numerous activating and inhibitory surface receptors that accumulate at the immune synapse. Quantitative analysis of receptor dynamics has been limited by methodologies which rely on indirect measurements such as fluorescence recovery after photobleaching. Here, we report a novel approach to study how proteins traffic to and from the immune synapse using NK cell receptors tagged with the photoswitchable fluorescent protein tdEosFP, which can be irreversibly photoswitched from a green to red fluorescent state by ultraviolet light. Thus, following a localized switching event, the movement of the photoswitched molecules can be temporally and spatially resolved by monitoring fluorescence in two regions of interest. By comparing images with mathematical models, we evaluated the diffusion coefficient of the receptor KIR2DL1 (0.23 +- 0.06 micron^2/s) and assessed how synapse formation affects receptor dynamics. Our data conclude that the inhibitory NK cell receptor KIR2DL1 is continually trafficked into the synapse and remains surprisingly stable there. Unexpectedly however, in NK cells forming synapses with multiple target cells simultaneously, KIR2DL1 at one synapse can relocate to another synapse. Thus, our results reveal a previously undetected inter-synaptic exchange of protein.Comment: 25 pages, 5 figure

Fusion majoritaire de bases de croyances ordonnées sans commensurabilité des échelles de référence

International audienceLa fusion de croyances provenant de différentes sources potentiellement contradictoires est un domaine de recherche qui a été très étudié ces dernières années. Cependant, les méthodes de fusion actuellement proposées se basent sur l'hypothèse implicite suivante : les échelles de référence des différentes sources doivent être commensurables. Or cette hypothèse peut se révéler beaucoup trop forte si l'on considère des sources réellement hétérogènes. Nous proposons dans cet article d'adapter un opérateur de fusion majoritaire afin de traiter la fusion des bases de croyances supposées incommensurables. Pour cela, nous nous basons sur le concept d'échelles compatibles et nous montrons que cet opérateur est équivalent à un critère de Pareto. Enfin nous montrons comment le fait de considérer un ensemble fini d'échelles compatibles permet à cet opérateur de respecter le postulat de majorité

Analyse du comportement d'opérateurs de fusion basés sur la somme : du cadre commensurable au cadre incommensurable

National audienceDifferent methods have been proposed in the literature for merging multiple and potentially conflicting informations. Sum-based operators offer a natural method for merging commensurable prioritized belief bases. Their popularity is due to the fact that they satisfy the majority property and they adopt a non cautious attitude in deriving plausible conclusions. This paper analyses the sum-based merging operator when sources to merge are incommensurable, namely they do not share the same meaning of uncertainty scales. We first show that the obtained merging operator can be equivalently characterized either in terms of an infinite set of compatible scales, or by a well-known Pareto ordering on a set of models. We then study different families of compatible scales useful for merging process. This paper also provides a postulates-based analysis of our merging operators

General Game Playing with Stochastic CSP - one page abstract

This paper has been published in Constraints 21, the Journal Fast Track issue of CP’1

General Game Playing with Stochastic CSP

selected for Journal Publication Fast Track in CP'15International audienc