Quantum Emulation of Gravitational Waves

Gravitational waves, as predicted by Einstein's general relativity theory, appear as ripples in the fabric of spacetime traveling at the speed of light. We prove that the propagation of small amplitude gravitational waves in a curved spacetime is equivalent to the propagation of a subspace of electromagnetic states. We use this result to propose the use of entangled photons to emulate the evolution of gravitational waves in curved spacetimes by means of experimental electromagnetic setups featuring metamaterials.Comment: 10 pages, 2 figure

Multi-Scale Simulation of Nonlinear Thin-Shell Sound with Wave Turbulence

International audienceThin shells — solids that are thin in one dimension compared to the other two — often emit rich nonlinear sounds when struck. Strong excitations can even cause chaotic thin-shell vibrations, producing sounds whose energy spectrum diffuses from low to high frequencies over time — a phenomenon known as wave turbulence. It is all these nonlinearities that grant shells such as cymbals and gongs their characteristic " glinting " sound. Yet, simulation models that efficiently capture these sound effects remain elusive. We propose a physically based, multi-scale reduced simulation method to synthesize nonlinear thin-shell sounds. We first split nonlinear vibrations into two scales, with a small low-frequency part simulated in a fully nonlinear way, and a high-frequency part containing many more modes approximated through time-varying linearization. This allows us to capture interesting nonlinearities in the shells' deformation, tens of times faster than previous approaches. Furthermore, we propose a method that enriches simulated sounds with wave turbulent sound details through a phenomenological diffusion model in the frequency domain, and thereby sidestep the expensive simulation of chaotic high-frequency dynamics. We show several examples of our simulations, illustrating the efficiency and realism of our model

Bioactivos naturales en mermeladas de ciruelas

El presente trabajo tiene como objetivo elaborar a escala de laboratorio mermeladas de ciruela con propiedades funcionales. Para tal fin se elaboraron mermeladas ajustando ciertos parámetros de elaboración para lograr un producto con mejor calidad nutricional que las disponibles en el mercado. Por otro lado, se obtuvieron tres concentrados de ciruelas en polvo mediante distintos procesos. Uno de estos concentrados fue utilizado para aditivar una de las mermeladas elaboradas. Por último se midió la actividad antioxidante (AA) y el contenido de antocianinas (AC) en las mermeladas de elaboración propia y se las comparó con las mermeladas comercializadas en CABA y GBA. Los valores de AA y AC de las mermeladas de elaboración propia fueron significativamente superiores a los obtenidos de las mermeladas comerciales. El concentrado de ciruela utilizado para aditivar una de las mermeladas resultó tener una elevada concentración de AC y aumentó notoriamente el contenido de AA y AC en la mermelada aditivada con dicho concentrado.EEA San PedroFil: Reich, Gustavo. INTI Agroalimentos. Centro de Investigación y Desarrollo en Tecnologías e Industrialización de Alimentos; ArgentinaFil: Murano, Mariana. INTI Agroalimentos. Centro de Investigación y Desarrollo en Tecnologías e Industrialización de Alimentos; ArgentinaFil: González, Julieta. INTI Agroalimentos. Centro de Investigación y Desarrollo en Tecnologías e Industrialización de Alimentos; ArgentinaFil: Pettinari, Víctor. INTI Agroalimentos. Centro de Investigación y Desarrollo en Tecnologías e Industrialización de Alimentos; ArgentinaFil: Barbagallo, Gustavo. INTI Agroalimentos. Centro de Investigación y Desarrollo en Tecnologías e Industrialización de Alimentos; ArgentinaFil: Cirio, Mercedes. INTI Agroalimentos. Centro de Investigación y Desarrollo en Tecnologías e Industrialización de Alimentos; ArgentinaFil: Villarreal, Marcela. INTI Agroalimentos. Centro de Investigación y Desarrollo en Tecnologías e Industrialización de Alimentos; ArgentinaFil: Kneetemann, Estela. INTI Agroalimentos. Centro de Investigación y Desarrollo en Tecnologías e Industrialización de Alimentos; ArgentinaFil: Valentini, Gabriel Hugo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Pedro; ArgentinaFil: Corbino, Graciela Beatriz. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Pedro; ArgentinaFil: Dománico, Ricardo. INTI Agroalimentos. Centro de Investigación y Desarrollo en Tecnologías e Industrialización de Alimentos; Argentin

Retour Multimodal et Techniques d'Interaction pour des Environnements Virtuels Basés Physique et Larges

Virtual Reality allows the simulation and interaction with Virtual Environments (VE) through different sensory modalities. However, interacting with complex physically based VE, such as non-rigid or large environments, presents many challenges in terms of interaction and sensory feedback. The first part of this Ph.D. thesis addresses haptic and multimodal feedback issues during manipulation of non-rigid media. We first present a novel approach for 6 degrees of freedom haptic interaction with fluids, allowing the generation of force feedback from viscous fluids through arbitrary-shaped rigid bodies. This approach is extended by including the haptic interaction with deformable bodies, thus allowing a unified haptic interaction with the different states of matter. A perceptual experiment showed that users could efficiently identify the different states through the haptic modality alone. Then, we introduce a novel vibrotactile fluid rendering model, leveraging previous knowledge on fluid sound synthesis. Through this approach, we allow the interaction with fluids with multimodal feedback, through vibrotactile, kinesthetic, acoustic and visual sensory channels. The second part of this Ph.D. thesis addresses interaction issues during walking navigation of large VE. Since the VE is often larger than the available real workspace, we introduce a novel navigation metaphor that informs users about the real physical boundaries. Using hybrid position/rate control, this technique provides a simple and intuitive metaphor for a navigation safe from collisions and breaks of immersion. Other workspaces, such as CAVE-like environments, present rotation boundaries due to missing screens. Thus, we present three novel metaphors dealing with these additional boundaries. Overall, the evaluation of these navigation techniques showed that they efficiently fulfilled their objectives while being highly appreciated by users.La Réalité Virtuelle permet de simuler et d'interagir avec des Environnements Virtuels (EV) à travers différentes modalités sensorielles. Cependant, l'interaction avec des EV basés physique et complexes, comme des environnements non rigides ou larges, présente plusieurs défis en termes d'interaction et de retours sensoriels. Dans la première partie de cette thèse, nous abordons la manipulation de milieux non rigides avec du retour haptique et multimodal. Nous présentons tout d'abord une nouvelle approche pour l'interaction haptique à 6 degrés de liberté avec des fluides. Cette approche permet la génération de retours de force lors de l'interaction avec des fluides visqueux par le biais d'objets rigides de forme arbitraire. Nous étendons ensuite cette approche pour inclure l'interaction haptique avec des objets déformables, menant donc à une interaction haptique unifiée avec les différents états de la matière. Une expérience perceptuelle nous a permis de montrer que les utilisateurs peuvent identifier de façon efficace les différents états en n'utilisant que la modalité haptique. Ensuite, nous présentons un nouveau modèle vibrotactile pour le rendu de fluides, tirant parti de connaissances dans la synthèse de son de fluides. A travers cette approche, nous rendons possible l'interaction avec des fluides tout en générant des retours multimodaux, utilisant les canaux sensoriels vibrotactile, kinesthésique, acoustique et visuel. Dans la seconde partie de cette thèse, nous abordons la navigation basée sur la marche dans des EV larges. Comme les EV sont souvent plus larges que l'espace de travail réel, nous présentons une nouvelle technique de navigation qui permet à l'utilisateur de connaître de façon immersive les limites de son espace de travail en translation. En utilisant un contrôle hybride en position/vitesse, cette technique fournit une métaphore simple et intuitive pour une navigation libre de collisions et de ruptures d'immersion. Comme certains espaces de travail présentent aussi des limites en rotation dues à des écrans manquants, comme dans le cas d'un CAVE, nous proposons ensuite trois nouvelles métaphores de navigation abordant ce problème supplémentaire. L'évaluation de ces techniques de navigation a permis de montrer qu'elles remplissent efficacement leurs objectifs tout en étant très appréciées par les utilisateurs

A Framework for Data-Driven Progressive Mesh Compression

International audienceProgressive mesh compression techniques have reached very high compression ratios. However, these techniquesusually do not take into account associated properties of meshes such as colors or normals, no matter their size, nor do they try to improve the quality of the intermediate decompression meshes. In this work, we propose a framework that uses the associated properties of the mesh to drive the compression process, resulting in an improved quality of the intermediate decompression meshes. Based on a kd-tree geometry compression algorithm, the framework is generic enough to allow any property or set of properties to drive the compression process provided the user defines a distance function for each property. The algorithm builds the kd-tree structure using a voxelisation process, which recursively separates the set of vertices according to the associated properties distances. We evaluate our method by comparing its compression ratios to recent algorithms. In order to evaluate the visual quality of the intermediate meshes, we carried a perceptive evaluation with human subjects. Results show that at equal rates, our method delivers an overall better visual quality. The algorithm is particularly well suited for the compression of meshes where geometry and topology play a secondary role compared to associated properties, such as with many scientific visualization models

A Framework for Data-Driven Progressive Mesh Compression

International audienceProgressive mesh compression techniques have reached very high compression ratios. However, these techniquesusually do not take into account associated properties of meshes such as colors or normals, no matter their size, nor do they try to improve the quality of the intermediate decompression meshes. In this work, we propose a framework that uses the associated properties of the mesh to drive the compression process, resulting in an improved quality of the intermediate decompression meshes. Based on a kd-tree geometry compression algorithm, the framework is generic enough to allow any property or set of properties to drive the compression process provided the user defines a distance function for each property. The algorithm builds the kd-tree structure using a voxelisation process, which recursively separates the set of vertices according to the associated properties distances. We evaluate our method by comparing its compression ratios to recent algorithms. In order to evaluate the visual quality of the intermediate meshes, we carried a perceptive evaluation with human subjects. Results show that at equal rates, our method delivers an overall better visual quality. The algorithm is particularly well suited for the compression of meshes where geometry and topology play a secondary role compared to associated properties, such as with many scientific visualization models