A predictive approach for a real-time remote visualization of large meshes

Déjà sur HALRemote access to large meshes is the subject of studies since several years. We propose in this paper a contribution to the problem of remote mesh viewing. We work on triangular meshes. After a study of existing methods of remote viewing, we propose a visualization approach based on a client-server architecture, in which almost all operations are performed on the server. Our approach includes three main steps: a first step of partitioning the original mesh, generating several fragments of the original mesh that can be supported by the supposed smaller Transfer Control Protocol (TCP) window size of the network, a second step called pre-simplification of the mesh partitioned, generating simplified models of fragments at different levels of detail, which aims to accelerate the visualization process when a client(that we also call remote user) requests a visualization of a specific area of interest, the final step involves the actual visualization of an area which interest the client, the latter having the possibility to visualize more accurately the area of interest, and less accurately the areas out of context. In this step, the reconstruction of the object taking into account the connectivity of fragments before simplifying a fragment is necessary.Pestiv-3D projec

Multi-scale morphology of the galaxy distribution

Many statistical methods have been proposed in the last years for analyzing the spatial distribution of galaxies. Very few of them, however, can handle properly the border effects of complex observational sample volumes. In this paper, we first show how to calculate the Minkowski Functionals (MF) taking into account these border effects. Then we present a multiscale extension of the MF which gives us more information about how the galaxies are spatially distributed. A range of examples using Gaussian random fields illustrate the results. Finally we have applied the Multiscale Minkowski Functionals (MMF) to the 2dF Galaxy Redshift Survey data. The MMF clearly indicates an evolution of morphology with scale. We also compare the 2dF real catalog with mock catalogs and found that Lambda-CDM simulations roughly fit the data, except at the finest scale.Comment: 17 pages, 19 figures, accepted for publication in MNRA

Numerical investigation of energy potential and performance of a residential building-integrated solar micro-CHP system

International audienceThe studied micro-CHP unit converts concentrated solar energy into electricity and heat by coupling a 46.5 m² parabolic trough collector with an oil-free single-cylinder steam engine operating according to the Hirn cycle. Originalities of this system are two axis solar tracking and direct steam generation. The exhaust heat of the cycle is recovered to cover building's heat needs, while the electricity is either self-consumed or fed back into the electricity grid. Experimental studies have shown that it is impossible to achieve continuous operation of the facility without an additional heat source. Thus, we are studying solutions for integrating a backup heating system from dynamic thermal simulations performed with TRNSYS© software One of them consists in adding a 30 kW boiler to the primary circuit in order to ensure daily electricity production. However, this is restricted by the considered storage tank. A parametric study on the volume of the storage tank makes it possible to propose an optimal solution for heat recovery. The results indicate that a storage volume of 3 m 3 meets the needs of the building and limits the heat losses due to heat storage. In order to optimize the use of such a micro-CHP unit, a heat sharing between several buildings equipped with 3 m 3 storage seems therefore to be a coherent solution

La reconstitution de la colonne des danseuses de Delphes

International audienceLocated on Apollo’s sanctuary in Delphi, the column of the dancers was discovered in 1894 by archaeologists of École française d’Athènes dismantled into 260 fragments. It stands as the tallest votive column of classical Greece – 14 meters – and the first to display a capital with acanthus leaves. But its division induced interpretation difficulties: since 1993, J.-L Martinez studies the hypothesis formulated by P. Amandry, a column topped by an omphalos, white stone held as the word’s navel. To support his search, a team of computer scientists from EDF and INRIA, ENST, MENSI, and artists from IIM have designed a methodology to heighten the monument in three dimensions and check the archaeological hypothesis. The 34 fragments to be joined were virtually moved to their original places thanks to software dedicated to the processing of hundreds of millions of laser point cloud. The data were then meshed and rendered with shadows to display the geometric details to be published. The column was then virtually integrated into the Delphic scenery. This project was conducted under the patronage of EDF Foundation, for École française d’Athènes, with the help of the Louvre Museum.Érigée sur le site du sanctuaire d’Apollon à Delphes, la colonne des danseuses fut découverte en 1894 par des chercheurs de l’École française d’Athènes sous la forme de plus de 260 fragments. Composée d’une colonne végétale à laquelle semble s’adosser un groupe sculpté de trois figures féminines, il s’agit de la plus haute colonne votive de la Grèce antique – 14 mètres – et la première attestée à présenter un chapiteau à feuilles d’acanthe. Conservée au musée de Delphes, elle continue de présenter des difficultés d’interprétation du fait de son morcellement. Depuis 1993, J.-L Martinez étudie l’hypothèse émise par P. Amandry selon laquelle la colonne était surmontée d’un omphalos, pierre qui selon les Anciens marquait le centre du monde. À sa demande, une équipe formée de chercheurs d’EDF et des partenaires dont les principaux sont l’INRIA, l’ENST et MENSI ainsi que d’artistes de l’IIM, a bâti une méthode de remontage du monument en trois dimensions permettant de vérifier les hypothèses archéologiques. 34 fragments à raccorder ont ainsi été remontés virtuellement grâce à un logiciel de traitement de mesures laser dans un relevé complet intégrant les 260 éléments. La grande nouveauté de cet outil d’anastylose est sa capacité à traiter des centaines de millions de mesures. Le nuage de points fut ensuite maillé puis ombré pour faire ressortir les détails géométriques aux fins de publication scientifique. La colonne fut finalement restituée au plus proche de son état originel, intégrée dans le paysage delphique. Ce projet a été mené dans le cadre des actions de mécénat de compétences de la Fondation EDF, au bénéfice de l’École française d’Athènes, avec le concours du Musée du Louvre

Software assembly and open standards for driving simulation

Driving simulation systems involve a combination of different computation codes. Although some of these modules are application-specific, their majority is reusable and state-of-the-art implementations are readily available in the open source community. This study investigates whether these open source libraries can combine to build a driving simulation application with reasonable performance. To this end, a component-oriented architecture is proposed, in which modules encapsulate relevant libraries behind a standard interface and exchange simulation data through a message passing interface. By integrating a render engine, a physics library and a simple vehicle dynamics model, we were able to rapidly build a functional minimal simulation application supporting distributed execution over a cluster of computers. As this architecture allows the transparent modification of module code and simplifies the addition of new modules, this kernel represents the foundations of an extensible and reconfigurable open source system dedicated to driving simulation. Details on this kernel application and ongoing development of this platform can found at http://open-s.sourceforge.net.Les logiciels de simulation de conduite reposent sur une combinaison de différents codes de calculs. Bien qu’une partie de ces modules soit extrêmement dépendante d’un usage particulier, leur majorité est réutilisable et certaines implémentations de pointe sont disponibles dans la communauté du logiciel libre. Cette étude vise à déterminer s’il est possible de combiner ces bibliothèques libres afin de construire une application de simulation de conduite atteignant de raisonnables performances. A cette fin, nous proposons une architecture orientée composant, selon laquelle ces bibliothèques sont encapsulées dans des modules s’échangeant des données relatives à la simulation au travers d’une interface d’échange de messages. En intégrant à cette architecture un moteur graphique, une bibliothèque de simulation de physique et un simple modèle de dynamique de véhicule, nous avons pu rapidement mettre en place une application de simulation minimale, pouvant s’exécuter de manière distribuée sur un cluster d’ordinateurs. Cette architecture permettant de modifier le code d’un module de manière transparente et simplifiant l’ajout de nouveaux modules, ce noyau constitue la base d’un logiciel libre extensible et polymorphique dédié à la simulation de conduite dont les détails peuvent être consultés sur le site : http://open-s.sourceforge.net

Software assembly and open standards for driving simulation

International audienceDriving simulation systems involve a combination of different computation codes. Although some of these modules are application-specific, their majority is reusable and state-of-the-art implementations are readily available in the open source community. This study investigates whether these open source libraries can combine to build a driving simulation application with reasonable performance. To this end, a component-oriented architecture is proposed, in which modules encapsulate relevant libraries behind a standard interface and exchange simulation data through a message passing interface. By integrating a render engine, a physics library and a simple vehicle dynamics model, we were able to rapidly build a functional minimal simulation application supporting distributed execution over a cluster of computers. As this architecture allows the transparent modification of module code and simplifies the addition of new modules, this kernel represents the foundations of an extensible and reconfigurable open source system dedicated to driving simulation. Details on this kernel application and ongoing development of this platform can found at http://open-s.sourceforge.net.Les logiciels de simulation de conduite reposent sur une combinaison de différents codes de calculs. Bien qu’une partie de ces modules soit extrêmement dépendante d’un usage particulier, leur majorité est réutilisable et certaines implémentations de pointe sont disponibles dans la communauté du logiciel libre. Cette étude vise à déterminer s’il est possible de combiner ces bibliothèques libres afin de construire une application de simulation de conduite atteignant de raisonnables performances. A cette fin, nous proposons une architecture orientée composant, selon laquelle ces bibliothèques sont encapsulées dans des modules s’échangeant des données relatives à la simulation au travers d’une interface d’échange de messages. En intégrant à cette architecture un moteur graphique, une bibliothèque de simulation de physique et un simple modèle de dynamique de véhicule, nous avons pu rapidement mettre en place une application de simulation minimale, pouvant s’exécuter de manière distribuée sur un cluster d’ordinateurs. Cette architecture permettant de modifier le code d’un module de manière transparente et simplifiant l’ajout de nouveaux modules, ce noyau constitue la base d’un logiciel libre extensible et polymorphique dédié à la simulation de conduite dont les détails peuvent être consultés sur le site : http://open-s.sourceforge.net

An efficient approach for human motion data mining based on curves matching

In this paper, we present a novel and efficient approach to retrieve human motion capture data as used in data-driven computer games, animated movies and special effects in the aim of finding a specific motion. From the kinematic chain model, the human motion capture data is transformed to a spatial-temporal invariance representation called the motion feature representation, in which each segment of kinematic chain model is represented by an angle between itself and the root segment. We treat the human motion as a cluster of curves of angle. In the aim of finding a human motion capture data in a very large database, we propose a novel lower bounding distance called LB_Keogh_Lowe to speed up similarity search. In order to reduce the computational cost, we employ techniques to simplify the curves length of both the envelopes curves and the query data. The similarity between two human motions is measured by applying the constrained Dynamic Time Warping. We carry out an experimental analysis with various real motion capture dataset. The results demonstrate the efficiency of our approach in the context of the human motion capture data and the potentiality to apply it in others contexts of the time-series data retrieval.SimAction projec

Training-based on real-time motion evaluation for functional rehabilitation in virtual environment

One of the most effective applications of virtual reality (VR) in physical rehabilitation is training, where patients are trained for sequence decision-making in special situations presented in virtual environment. In this application, the evaluation of the movement of the subject performing a physical task is crucial. A good evaluation of the motion is necessary to follow the progression of the patient during his training session. Therefore, it helps therapist to better supervise therapeutic planning. Actually, the performance of the patient's training is determined by subjective observation of the therapist. Our approach is to propose a system that allows the patient to perform his training and to evaluate the progress of training in an autonomous way. This system consists of a motion analysis technique for a rehabilitation application where the patient is represented by his own avatar in virtual environment. The task performance required from the patient is his capability to reproduce in real time a movement. The real-time motion evaluation technique is based on the time series data matching method called Longest Common Sub-Sequence (hereafter LCSS). It is used to calculate distance between the reference motion of virtual avatar and the captured motion data of the patients and thus is used to determine how well the patients are doing during the training. The complexity of the technique proposed is in the order of O(δ) in which δ is a constant matching window size. Our prototype application is based on Tai-chi movements which have shown many health benefits and are increasingly used for therapeutic purposes.SIMACTION projec

Progressive Seizure Aggravation in the Repeated 6-Hz Corneal Stimulation Model Is Accompanied by Marked Increase in Hippocampal p-ERK1/2 Immunoreactivity in Neurons

The 6-Hz corneal stimulation test is used to screen novel antiepileptic molecules to overcome the problem of drug refractoriness. Although recognized as a standard test, it has been evaluated only recently in the attempt to characterize the putative neuronal networks involved in seizures caused by corneal stimulation. In particular, by recording from the CA1 region we previously established that the hippocampus participates to propagation of seizure activity. However, these findings were not corroborated by using markers of neuronal activation such as FosB/ΔFosB antigens. In view of this discrepancy, we performed new experiments to characterize the changes in levels of phosphorylated extracellular signal-regulated kinases1/2 (p-ERK1/2), which are also used as markers of neuronal activation. To this aim, mice underwent corneal stimulation up to three different times, in three sessions separated by an interval of 3 days. To characterize a group in which seizures could be prevented by pharmacological treatment, we also considered pretreatment with the ghrelin receptor antagonist EP-80317 (330 μg/kg). Control mice were sham-treated. Video electrocorticographic (ECoG) recordings were obtained from mice belonging to each group of treatment. Animals were finally used to characterize the immunoreactivity for FosB/ΔFosB and p-ERK1/2 in the hippocampus. As previously shown, FosB/ΔFosB levels were highly increased throughout the hippocampus by the first induced seizure but, in spite of the progressively increased seizure severity, they were restored to control levels after the third stimulation. At variance, corneal stimulation caused a progressive increase in p-ERK1/2 immunoreactivity all over the hippocampus, especially in CA1, peaking in the third session. Predictably, EP-80317 administration reduced both duration and severity of seizures, prevented the increase in FosB/ΔFosB levels in the first session, and partially counteracted the increase in p-ERK1/2 levels in the third session. The vast majority of p-ERK1/2 immunopositive cells were co-labeled with FosB/ΔFosB antibodies, suggesting the existence of a relationship between the investigated markers in a subpopulation of neurons activated by seizures. These findings suggest that p-ERK1/2 are useful markers to define the aggravation of seizures and the response to anticonvulsant treatments. In particular, p-ERK1/2 expression clearly identified the involvement of hippocampal regions during seizure aggravation in the 6-Hz model