From decision to action : intentionality, a guide for the specification of intelligent agents' behaviour

International audienceThis article introduces a reflexion about behavioural specification for interactive and participative agent-based simulation in virtual reality. Within this context, it is neces sary to reach a high level of expressivness in order to enforce interactions between the designer and the behavioural model during the in-line prototyping. This requires to consider the need of semantic very early in the design process. The Intentional agent model is here exposed as a possible answer. It relies on a mixed imperative and declarative approach which focuses on the link between decision and action. The design of a tool able to simulate virtual environment implying agents based on this model is discus

In Vivo Detection of Succinate by Magnetic Resonance Spectroscopy as a Hallmark of SDHx Mutations in Paraganglioma

International audiencePurpose: Germline mutations in genes encoding mitochon-drial succinate dehydrogenase (SDH) are found in patients with paragangliomas, pheochromocytomas, gastrointestinal stromal tumors, and renal cancers. SDH inactivation leads to a massive accumulation of succinate, acting as an oncometabolite and which levels, assessed on surgically resected tissue are a highly specific biomarker of SDHx-mutated tumors. The aim of this study was to address the feasibility of detecting succinate in vivo by magnetic resonance spectroscopy. Experimental Design: A pulsed proton magnetic resonance spectroscopy (1 H-MRS) sequence was developed, optimized, and applied to image nude mice grafted with Sdhb À/À or wild-type chromaffin cells. The method was then applied to patients with paraganglioma carrying (n ¼ 5) or not (n ¼ 4) an SDHx gene mutation. Following surgery, succinate was measured using gas chromatography/mass spectrometry, and SDH protein expression was assessed by immunohistochemistry in resected tumors. Results: A succinate peak was observed at 2.44 ppm by 1 H-MRS in all Sdhb À/À-derived tumors in mice and in all paragangliomas of patients carrying an SDHx gene mutation, but neither in wild-type mouse tumors nor in patients exempt of SDHx mutation. In one patient, 1 H-MRS results led to the identification of an unsus-pected SDHA gene mutation. In another case, it helped define the pathogenicity of a variant of unknown significance in the SDHB gene. Conclusions: Detection of succinate by 1 H-MRS is a highly specific and sensitive hallmark of SDHx mutations. This non-invasive approach is a simple and robust method allowing in vivo detection of the major biomarker of SDHx-mutated tumors. Clin Cancer Res; 22(5); 1120–9. Ó2015 AACR

A gp41 MPER-specific llama VHH requires a hydrophobic CDR3 for neutralization but not for antigen recognition

The membrane proximal external region (MPER) of the HIV-1 glycoprotein gp41 is targeted by the broadly neutralizing antibodies 2F5 and 4E10. To date, no immunization regimen in animals or humans has produced HIV-1 neutralizing MPER-specific antibodies. We immunized llamas with gp41-MPER proteoliposomes and selected a MPER-specific single chain antibody (VHH), 2H10, whose epitope overlaps with that of mAb 2F5. Bi-2H10, a bivalent form of 2H10, which displayed an approximately 20-fold increased affinity compared to the monovalent 2H10, neutralized various sensitive and resistant HIV-1 strains, as well as SHIV strains in TZM-bl cells. X-ray and NMR analyses combined with mutagenesis and modeling revealed that 2H10 recognizes its gp41 epitope in a helical conformation. Notably, tryptophan 100 at the tip of the long CDR3 is not required for gp41 interaction but essential for neutralization. Thus bi-2H10 is an anti-MPER antibody generated by immunization that requires hydrophobic CDR3 determinants in addition to epitope recognition for neutralization similar to the mode of neutralization employed by mAbs 2F5 and 4E10

La notion d'intentionnalité dans la spécification de comportements d'agents autonomes situés en environnement virtuel

Rapporteurs : Philippe Mathieu (LIFL / Lille) Jean-Pierre Müller (CIRAD / Montpellier)This thesis lies within the scope of the specification of behaviors of autonomous agents situated in a virtual universe. The objective is the proposal for a behavioral model which exploits the concept of intention like semantic bond between the various stages of the cycle of software development. For this purpose, the concept of intention, and more largely of intentionnality, is studied under three different lightings in order to consider its employment appropriateness in the exercise of such a specification. The philosophical aspects (through the phenomenology and the analytic philosophy), the psychological and neurophysiological aspects of this concept are thus approached. What emerges from this analysis is that : · the role of the intention is fundamental in release, continuous control of execution and stop of the action ; · the role of intentionality within the dialogue between the different specialists involved in the specification process, the agent being then regarded as object of the speech. This study introduces a criticism of the existing approaches of behavioral specification, particularly BDI architectures (Belief Desire Intention). It appears that architectures which exploit the concept of intention use it like guide for planning or like concept of modeling. They are almost all symbolic approaches. These reflexions pose the bases of the suggested model: it is a reactive model which exploits the concept of intention to carry out a selection of action. The agent employs behavioral rules described in a declaratory language in order to generate intentions to satisfy, according to its situation. The exploitation of knowledge about the supposed effects of its actions on itself enables it to carry out a qualitative reasoning and to select the most suited action. The concept of intention thus makes it possible to establish a bond between a set of symbolic behavioral rules and a corpus of imperative methods (sensorimotor schemes of the agent) via clarification of the "meaning of the action". In addition, the introduction of this semantic bond within the model supports the communication between the various speakers involved in the specification process. The intentional stance offers the concepts necessary to the federation of the points of view of these various specialists. The translation of the behavior in the form of behavioral rules is done according to a semantic which is close to the ontology of the field approached by simulation, the concept of intention being common to the various phases of design, from the analysis to the implementation. After detailing the model resulting from this proposal, the technical needs for its execution and the final application, the thesis concludes on the benefits from this semantic contribution within a reactive model for the specification as a whole (from the analysis of the problem to the interpretation of the results) and draws the prospects for the design of hybrid architectures. The ways thus opened are primarily : · the learning by the agent of the supposed effect of its actions; · the exchange of know-how between agents; · the automatic generation of explanation, with a possible application in the virtual environments for training; · the development of a design method based on the behavioral model suggested.Cette thèse s'inscrit dans le cadre de la spécification de comportements d'agents autonomes situés dans un univers virtuel. L'objectif est la proposition d'un modèle comportemental qui exploite le concept d'intention comme lien sémantique entre les différentes étapes du cycle de d´eveloppement logiciel. A cette fin, la notion d'intention, et plus largement d'intentionnalité, est étudiée sous trois éclairages différents afin de considérer l'opportunité de son emploi dans l'exercice d'une telle spécification. Les aspects philosophiques (à travers la phénoménologie et la philosophie analytique), les aspects psychologiques et neurophysiologiques de cette notion sont ainsi abordés. Il ressort de cette analyse : · le rôle fondamental de l'intention dans le déclenchement, le contrôle en cours d'effectuation et l'arrêt de l'action ; · le rôle de l'intentionnalité dans le dialogue entre les différents intervenants impliqués dans le processus de spécification, l'agent étant alors l'objet de leur discours. Cette étude introduit une critique des approches de spécification comportementale existantes, particulièrement des architectures BDI (Belief Desire Intention). Il apparaît que celles qui exploitent la notion d'intention l'utilisent comme guide de la planification ou comme concept de modélisation. Il s'agit presque systèmatiquement d'approches symboliques. L'ensemble de ces réflexions pose les bases du modèle proposé : c'est un modèle réactif qui exploite la notion d'intention pour effectuer une sélection d'action. L'agent emploie des règles comportementales décrites dans un langage déclaratif afin de générer des intentions à satisfaire en fonction de sa situation. L'exploitation de connaissances des effets présumés de ses actions sur lui-même lui permet de mener un raisonnement qualitatif pour sélectionner l'action la plus adaptée. La notion d'intention permet donc d'établir un lien entre un ensemble de règles comportementales symboliques et un corpus de méthodes impératives (les schèmes sensori-moteurs de l'agent) via l'explicitation du "sens de l'action". D'autre part, l'instauration de ce lien sémantique au sein du modèle favorise la communication entre les différents intervenants impliqués dans la spécification du comportement. La proposition intentionnelle offre les concepts nécessaires à la fédération des points de vue de ces différents spécialistes. La traduction du comportement sous forme de règles comportementales se fait alors selon une sémantique proche de l'ontologie du domaine abordé par la simulation, le concept d'intention étant commun aux différentes phases de conception, depuis l'analyse jusqu'à l'implémentation. Après avoir détaillé le modèle issu de cette proposition, les prérequis techniques à son exécution et l'application réalisée, la thèse conclut sur les bénéfices de cet apport sémantique au sein d'un modèle réactif pour la spécification dans son ensemble (depuis l'analyse du problème jusqu'à l'interprétation des résultats) et dessine les perspectives en matière de conception d'architectures hybrides. Les voies ainsi ouvertes sont essentiellement : · l'apprentissage par l'agent de l'effet présumé de ses actions ; · l'échange de savoir-faire entre agents ; · la génération automatique d'explication, avec une application possible dans les environnements virtuels de formation ; · l'élaboration d'une démarche de conception basée sur le modèle comportemental proposé

Intentionality: a needed link between decision and action for intelligent's agent behaviour.

International audienceThis article introduces a reflexion about behavioural specification for interactive and participative agent-based simulation in virtual reality. Within this context, it is necessary to reach a high level of expressivness in order to enforce interactions between the designer and the behavioural model during the in-line prototyping. This requires to consider the need of semantic very early in the design process. This reflexion leads us to propose a kind of mixed imperative and declarative model which focuses on the link between decision and action, and to the building of a tool capable to simulate virtual environment implying agents based on this model. Intentionality is introduced as the basis of a behavioural model which is given as an example of this approach

Images des Amériques: fabrique, représentation, usages

International audienc

Images des Amériques: fabrique, représentation, usages

International audienc

La notion d'intentionnalité dans la spécification de comportements d'agents autonomes situés en environnement virtuel

Cette thèse s'inscrit dans le cadre de la spécification de comportements d'agents autonomes situés dans un univers virtuel. L'objectif est la proposition d'un modèle comportemental qui exploite le concept d'intention comme lien sémantique entre les différentes étapes du cycle de développement logiciel. A cette fin, la notion d'intention, est étudiée sous trois éclairages différents afin de considérer l'opportunité de son emploi dans l'exercice d'une telle spécification. Les aspects philosophiques, psychologiques et neurophysiologiques de cette notion sont ainsi abordés. Il ressort de cette analyse : - le rôle fondamental de l'intention dans le déclenchement, le contrôle et l'arrêt de l'action ; - le rôle de l'intentionnalité dans le dialogue entre les différents intervenants impliqués dans le processus de spécification, l'agent étant alors l'objet de leur discours. L'ensemble de ces réflexions pose les bases du modèle proposé : c'est un modèle réactif qui exploite la notion d'intention pour effectuer une sélection d'action. Cette dernière permet d'établir un lien entre un ensemble de règles comportementales symboliques et un corpus de méthodes impératives via l'explicitation du "sens de l'action". D'autre part, l'instauration de ce lien sémantique au sein du modèle favorise la communication entre les différents intervenants impliqués dans la spécification du comportement. Après avoir détaillé le modèle issu de cette proposition, les prérequis techniques à son exécution et l'application réalisée, la thèse conclut sur les bénéfices de cet apport sémantique et dessine les perspectives en matière de conception d'architectures hybridesThis thesis lies within the scope of the specification of behaviors of autonomous agents situated in a virtual universe. The objective is the proposal for a behavioral model which exploits the concept of intention like semantic bond between the various stages of the cycle of software development. For this purpose, the concept of intention is studied under three different lightings in order to consider its employment appropriateness in the exercise of such a specification. The philosophical, psychological and neurophysiological aspects of this concept are thus approached. What emerges from this analysis is that : · the role of the intention is fundamental in release, control and stop of the action ; · the role of intentionality within the dialogue between the different specialists involved in the specification process, the agent being then regarded as object of the speech. These reflexions pose the bases of the suggested model: it is a reactive model which exploits the concept of intention to carry out a selection of action. This concept makes it possible to establish a bond between a set of symbolic behavioral rules and a corpus of imperative methods via clarification of the "meaning of the action". In addition, the introduction of this semantic bond within the model supports the communication between the various speakers involved in the specification process. After detailing the model resulting from this proposal, the technical needs for its execution and the final application, the thesis concludes on the benefits from this semantic contribution within a reactive model for the specification as a whole and draws the prospects for the design of hybrid architectures.BREST-BU Droit-Sciences-Sports (290192103) / SudocLENS-CRIL (624982203) / SudocBREST-ENIB (290192307) / SudocSudocFranceF