Grimage: markerless 3D interactions

International audienceGrimage glues multi-camera 3D modeling, physical simulation and parallel execution for a new immersive experience. Put your hands or any object into the interaction space. It is instantaneously modeled in 3D and injected into a virtual world populated with solid and soft objects. Push them, catch them and squeeze them

Modularity for Large Virtual Reality Applications

International audienceThis paper focuses on the design of high performance VR applications. These applications usually involve various I/O devices and complex simulations. A parallel architecture or grid infrastructure is required to provide the necessary I/O and processing capabilities. Developing such applications faces several difficulties, two important ones being software engineering and performance issues. We argue that application modularity is a key concept to help the developer handle the complexity of these applications. We discuss how various approaches borrowed from other existing works can be combined to significantly improve the modularity of VR applications. This led to the development of the FlowVR middleware that associates a data-flow model with a hierarchical component model. Different case studies are presented to discuss the benefits of the approach proposed

Commodity Computing Clusters at Goddard Space Flight Center

The purpose of commodity cluster computing is to utilize large numbers of readily available computing components for parallel computing to obtaining the greatest amount of useful computations for the least cost. The issue of the cost of a computational resource is key to computational science and data processing at GSFC as it is at most other places, the difference being that the need at GSFC far exceeds any expectation of meeting that need. Therefore, Goddard scientists need as much computing resources that are available for the provided funds. This is exemplified in the following brief history of low-cost high-performance computing at GSFC

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

A Visual Analytics Framework for Reviewing Streaming Performance Data

Understanding and tuning the performance of extreme-scale parallel computing systems demands a streaming approach due to the computational cost of applying offline algorithms to vast amounts of performance log data. Analyzing large streaming data is challenging because the rate of receiving data and limited time to comprehend data make it difficult for the analysts to sufficiently examine the data without missing important changes or patterns. To support streaming data analysis, we introduce a visual analytic framework comprising of three modules: data management, analysis, and interactive visualization. The data management module collects various computing and communication performance metrics from the monitored system using streaming data processing techniques and feeds the data to the other two modules. The analysis module automatically identifies important changes and patterns at the required latency. In particular, we introduce a set of online and progressive analysis methods for not only controlling the computational costs but also helping analysts better follow the critical aspects of the analysis results. Finally, the interactive visualization module provides the analysts with a coherent view of the changes and patterns in the continuously captured performance data. Through a multi-faceted case study on performance analysis of parallel discrete-event simulation, we demonstrate the effectiveness of our framework for identifying bottlenecks and locating outliers.Comment: This is the author's preprint version that will be published in Proceedings of IEEE Pacific Visualization Symposium, 202

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

Focusing Attention on the Health Aspects of Foods Changes Value Signals in vmPFC and Improves Dietary Choice

Attention is thought to play a key role in the computation of stimulus values at the time of choice, which suggests that attention manipulations could be used to improve decision-making in domains where self-control lapses are pervasive. We used an fMRI food choice task with non-dieting human subjects to investigate whether exogenous cues that direct attention to the healthiness of foods could improve dietary choices. Behaviorally, we found that subjects made healthier choices in the presence of health cues. In parallel, stimulus value signals in ventromedial prefrontal cortex were more responsive to the healthiness of foods in the presence of health cues, and this effect was modulated by activity in regions of dorsolateral prefrontal cortex. These findings suggest that the neural mechanisms used in successful self-control can be activated by exogenous attention cues, and provide insights into the processes through which behavioral therapies and public policies could facilitate self-control