Real-Time Numerical Simulation for Accurate Soft Tissues Modeling during Haptic Interaction

The simulation of fabrics physics and its interaction with the human body has been largely studied in recent years to provide realistic-looking garments and wears specifically in the entertainment business. When the purpose of the simulation is to obtain scientific measures and detailed mechanical properties of the interaction, the underlying physical models should be enhanced to obtain better simulation accuracy increasing the modeling complexity and relaxing the simulation timing constraints to properly solve the set of equations under analysis. However, in the specific field of haptic interaction, the desiderata are to have both physical consistency and high frame rate to display stable and coherent stimuli as feedback to the user requiring a tradeoff between accuracy and real-time interaction. This work introduces a haptic system for the evaluation of the fabric hand of specific garments either existing or yet to be produced in a virtual reality simulation. The modeling is based on the co-rotational Finite Element approach that allows for large displacements but the small deformation of the elements. The proposed system can be beneficial for the fabrics industry both in the design phase or in the presentation phase, where a virtual fabric portfolio can be shown to customers around the world. Results exhibit the feasibility of high-frequency real-time simulation for haptic interaction with virtual garments employing realistic mechanical properties of the fabric materials

Haptic Rendering of Juggling with Encountered Haptic Interfaces.

Haptic interaction in a virtual world can be tool mediated or direct; and, among direct interactions, the encountered haptic interfaces provide physical contact only when there is contact with a virtual object. This paper deals with the haptic rendering of the catching and throwing of objects by means of this type of interface. A general model for the rendering of the impact is discussed with the associated formalism for managing multiple objects and multiple devices. Next, a key parameter for simulating the impact is selected by means of a psychophysical test. Finally, a working system is presented with the application of the rendering strategy to the case of haptic juggling, showing the possibility of effectively performing basic juggling patterns with two balls

Energy management using virtual reality improves 2000-m rowing performance

Elite-standard rowers tend to use a fast-start strategy followed by an inverted parabolic-shaped speed profile in 2000-m races. This strategy is probably the best to manage energy resources during the race and maximise performance. This study investigated the use of virtual reality (VR) with novice rowers as a means to learn about energy management. Participants from an avatar group (n = 7) were instructed to track a virtual boat on a screen, whose speed was set individually to follow the appropriate to-be-learned speed profile. A control group (n = 8) followed an indoor training programme. In spite of similar physiological characteristics in the groups, the avatar group learned and maintained the required profile, resulting in an improved performance (i.e. a decrease in race duration), whereas the control group did not. These results suggest that VR is a means to learn an energy-related skill and improve performance

Dynamique et approche quantitative des remplissages fini- et postwürmiens du bassin lacustre de Cerin (Jura, France)

National audienceIn the southern Jura mountains, the lake of Cerin is located in an area reached by the maximum Rhône Würmian glacial advance. The retreat of the glacial front occurred after 18.000 years B.P. The glacial tongue of Cerin has overdeeped a lacustrine basin of 35 acres which is nowadays almost filled up. The morphology of the basin, the nature and geometry of the lacustrine infillings were determinated by geophysical prospecting and 52 core drillings. Their chronology is based on pollen stratigraphy and 14 radiocarbon datings. These chronological references added to a computerized processing of sedimentological data are taken into account for a reconstruction of the main successive phases of deposit accumulation in the basin and its dynamics of filling up. For each chronological phase we calculated the mean thickness, density and volumes of the sedimentary facies stored in the natural lacustrine depression. So as to get more accurate information about the impact of climate and vegetation on the sedimentary process, we studied the evolution of the volumes stored in relation, both with the dynamic of filling up and with the environment modifications that occurred during the late glacial and holocene periods. Results show that variations in sediment accumulation rates reflect a complex interaction between sedimentary process and climatic oscillations.Dans la terminaison méridionale du Jura, le lac de Cerin (Ain) se situe dans la zone atteinte par le glacier würmien du Rhône au maximum de sa progression. Le retrait du front glaciaire après 18 000 B.P. a permis l'installation dans une dépression surcreusée, d'un lac de 14 ha. pratiquement comblé aujourd'hui. La morphologie du bassin lacustre, la nature et la géométrie des remplissages ont été reconnues grâce à des prospections géophysiques et à 52 forages carottés ; leur chronologie a été fixée à partir des données palynologiques et de 14 datations radiocarbone. Ces références chronologiques et le traitement informatisé des données sédimentologiques ont permis de reconstituer les grandes étapes de l'évolution du comblement du bassin et de restituer sa dynamique sédimentaire. En outre, une évaluation des épaisseurs, des volumes et des masses des sédiments lacustres déposés par lithofaciès et par chronozones palynologiques a été réalisée pour l'ensemble du bassin. Les variations dans la quantification sont analysées par rapport à la dynamique de comblement, aux fluctuations climatiques et à l'évolution du couvert végétal depuis la dernière glaciation. Les résultats font apparaître une interaction complexe entre processus sédimentaires et phénomènes climatiques

Orbital imprint on Holocene paleohydrological variations in west-central Europe as reflected by lake-level changes at Cerin-Jura Mountains, eastern France

International audienceThis paper presents a lake-level record for the Holocene at Lake Cerin Jura Mountains, eastern France. It is based on a range of sedimentological techniques validated in previous studies, with a combination of systematic lithostratigraphic investigations of the infillings accumulated in the lacustrine basin, and sediment analyses of two selected cores. The chronology is based on 10 radiocarbon dates and pollen stratigraphy. On a millennial scale, the Cerin lake-level record shows three distinct successive phases characterised by higher lake-level conditions until ca. 9000 cal. a BP, followed by a maximal lowering at ca. 90008500 cal. a BP, and a progressive rise until the present. This rise was punctuated by centennial-scale fluctuations, with major events around 4000, 2800 and after 1500 cal. a BP. Considered on a multimillennial scale, the general pattern of palaeohydrological changes reconstructed at Cerin reflects the impact of orbitally driven summer insolation. This is in agreement with other regional and extra-regional palaeoclimatic records, although every record shows peculiarities in timing and shape depending on the proxy used for reconstruction. In this general context, centennial to multicentennial oscillations appear to have been second-order events in comparison with the major influence of the orbital factor

Unité fluviatile à échardes volcaniques d’un interstade à Bétula/Pinus antérieur à 53ka (début du MIS3) et optimum glaciaire pendant le MIS4 au nord des Vosges Centrales

National audienceA continuous sedimentary sequence has been deposited for more than 53 ka in the Fave River Valley, laterally to the intra-Vosgian basin of St-Dié. The coarse material of the lower alluvial sheet of the sequence is the result of torrential flows from melting neves and ice masses accumulated during MIS 4 on the highlands at the South of the valley. The upper alluvial silty sheet records a slow deposition of fine sediments without interstratified torrential beds. There was no significant accumulation of neves or ice on the southern watershed of the Fave River during the LGM and Late Glacial. The upper sheet of the sequence contains a stratified and discontinuous peaty basal unit dated to more than 53 ka and containing volcanic glass shards and interstadial Betula/Pinus pollen followed by stadial cold steppic species. The local interstadial is correlated to the Goulotte episode of the pollen sequence of Grande Pile, at the beginning of MIS 3. The age is compatible with the St-Germain tephra. These data from the northern edge of the central Vosges Mountains provide further support for the glacial model established in southern Vosges, with early heavy snowfalls during the beginning of the Middle Würmian (MIS 4) and smaller extent of the glaciers with dryer and colder climatic conditions during late Würmian (MIS 2).Latérale au bassin intra-vosgien de Saint-Dié, la vallée de la Fave a enregistré une séquence sédimentaire continue depuis plus de 53 ka. Le matériel de la nappe grossière inférieure résulte d’apports torrentiels attribués à un épisode de fonte de névés et de masses de glace accumulés pendant le stade MIS 4 sur les reliefs au sud de la vallée. La nappe alluviale supérieure, à dominante silteuse, indique une sédimentation lente sans épisode torrentiel et l’absence d’accumulation significative de névés ou de glace sur le bassin versant pendant le Dernier Maximum Glaciaire et le Tardiglaciaire. Elle inclut une unité basale stratifiée et discontinue à échardes volcaniques, à matière organique datée à plus de 53 ka et de contenu pollinique à Betula/Pinus suivis d’espèces de steppe froide. L’Interstade local est dans la position palynostratigraphique de l’Interstade de Goulotte de la séquence de la Grande Pile, au début du MIS 3. Cet âge est compatible avec celui du tephra de Saint-Germain. Ces données sur la marge nord des Vosges centrales confirment le modèle d’histoire glaciaire mis en évidence dans les Vosges du sud, avec un maximum d’enneigement précoce au début du Würmien moyen (MIS 4) et une extension glaciaire plus restreinte sous climat froid et sec pendant le Würmien supérieur (MIS 2)