Dynamic Shapes Average

International audienceA framework for computing shape statistics in general, and average in particular, for dynamic shapes is introduced in this paper. Given a metric d(*, *) on the set of static shapes, the empirical mean of N static shapes,C1, . . . ,CN, is defined by arg min d(C,Ci)^2. The purpose of this paper is to extend this shape average work to the case of N dynamic shapes and to give an efficient algorithm to compute it. The key concept is to combine the static shape statistics approach with a time-alignment step. To align the time scale while performing the shape average we use dynamic time warping, adapted to deal with dynamic shapes. The proposed technique is independent of the particular choice of the shape metric d(*, *). We present the underlying concepts, a number of examples, and conclude with a variational formulation to address the dynamic shape average problem. We also demonstrate how to use these results for comparing different types of dynamics. Although only average is addressed in this paper, other shape statistics can be similarly obtained following the framework here proposed

Observatoires et gouvernance territoriale : une approche par la co-construction de modèles

International audienceObservatories, defined as sociotechnical devices for observation, analysis and debate, tend increasingly to play a key role in territorial governance. Political, semantical and organizational difficulties arise then, and the risks of failure are many. After analyzing these difficulties, we describe two models and explain how then can remediate: the " model of action " and the " observation model ". We then articulate the co-construction of these models and the more technical tasks of information system building within the Co-Obs method.Les observatoires, définis comme des dispositifs sociotechniques d'observation, d'analyse et de mise en débat, tendent de plus en plus à devenir des supports majeurs de la gouvernance au sein des territoires. Des difficultés politiques, sémantiques et organisationnelles surgissent alors, et les risques d'échec sont nombreux. Après avoir analysé ces difficultés, nous décrivons deux modèles pour les aborder fructueusement lors de la construction de l'observatoire : le « modèle de l'action » et le « modèle de l'observation ». Nous articulons ensuite, au sein de la méthode originale Co-Obs, la co-construction de ces modèles avec les tâches plus techniques de développement du système d'information

Symmetrical EEG-FMRI Imaging by Sparse Regularization

International audienceThis work considers the problem of brain imaging using simultaneously recorded electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). To this end, we introduce a linear coupling model that links the electrical EEG signal to the hemodynamic response from the blood-oxygen level dependent (BOLD) signal. Both modalities are then symmetrically integrated, to achieve a high resolution in time and space while allowing some robustness against potential decoupling of the BOLD effect. The novelty of the approach consists in expressing the joint imaging problem as a linear inverse problem, which is addressed using sparse regularization. We consider several sparsity-enforcing penalties, which naturally reflect the fact that only few areas of the brain are activated at a certain time, and allow for a fast optimization through proximal algorithms. The significance of the method and the effectiveness of the algorithms are demonstrated through numerical investigations on a spherical head model

3D model fitting for facial expression analysis under uncontrolled imaging conditions

International audienceThis paper addresses the recovering of 3D pose and animation of the human face in a monocular single image under uncontrolled imaging conditions. Our goal is to fit a 3D animated model in a face image with possibly large variations of head pose and facial expressions. Our data were acquired from filmed epileptic seizures of patients undergoing investigation in the videotelemetry 1unit, La Timone hospital, Marseille, France

SCoRe: a Self-Organizing Multi-Agent System for Decision Making in Dynamic Software Developement Processes

International audienceSoftware systems are becoming more and more complex. A common dilemma faced by software engineers in building complex systems is the lack of method adaptability. However, existing agent-based methodologies and tools are developed for particular system and are not tailored for new problems. This paper proposes an architecture of a new tool based on SME for self-constructing customized method processes. Our approach is based on two pillars: the process fragment and the MAS meta-model. These two elements are both defined and considered under a specific agent-oriented perspective thus creating a peculiar approach. Our work is based on the self-organization of agents, making it especially suited to deal with highly dynamic systems such as the design of an interactive and adaptive software engineering process

Signes, Données et Représentations Spatiales (Des éléments de sens dans l'élaboration d'un projet de territoire intercommunal.)

A l heure d une société marquée par les technologies de l information, les territoires locaux sont soumis à des formes de développement de plus en plus dictées et encadrées par le haut, basées sur les paradigmes de l économie mondialisée et du développement durable. La question est alors de savoir comment ces territoires peuvent promouvoir un développement endogène qui fasse sens pour les acteurs locaux. Pour ce faire, nous inscrivons notre recherche dans les sciences de l information et de la communication en mobilisant le concept d intelligence territoriale. Nous apportons notre contribution à cette approche en approfondissant le rôle que peut jouer la dimension géographique dans les dispositifs socio-techniques d information et de communication (Distic) à l échelon des territoires intercommunaux. Nous adoptons pour cela une posture de recherche-intervention qui alterne des réflexions théoriques avec des observations et interventions empiriques sur une étude de cas, celle du territoire de Thau. Les représentations spatiales, comme produits médiatiques constitutifs des Distic, offrent une diversité de propriétés sémiotiques et de fonctionnalités que nous mettons en évidence. Nous utilisons aussi le métamodèle de Schwarz à un niveau macro pour rendre compte de la complexification et de l autonomisation progressive du territoire de Thau sur les vingt dernières années.At a time when information technology is ruling the world, local territories are subject to forms of development increasingly framed and dictated from above, based on the paradigms of the globalized economy and sustainable development. The issue then is to study how these territories can promote endogenous development that makes sense for local societies. To do so, we place our research in the field of information and communication sciences by using the concept of territorial intelligence. We contribute to this approach by deepening the potential role of the geographic dimension in information and communication socio-technical arrangements , or Distic, at the level of inter-municipal territories. We adopt an action-research stance that alternates theoretical reflections with empirical observations and actions on the Thau territory case study. Spatial representations, as constitutive of Distic media products, offer a variety of semiotic properties and features that we highlight. We also use the Schwarz s meta-model on a macro level to highlight the complexity and the and the gradual empowerment of the Thau territory over the past twenty years.TOULON-Bibliotheque electronique (830629901) / SudocSudocFranceF