From Driving Simulation to Virtual Reality

Driving simulation from the very beginning of the advent of VR technology uses the very same technology for visualization and similar technology for head movement tracking and high end 3D vision. They also share the same or similar difficulties in rendering movements of the observer in the virtual environments. The visual-vestibular conflict, due to the discrepancies perceived by the human visual and vestibular systems, induce the so-called simulation sickness, when driving or displacing using a control device (ex. Joystick). Another cause for simulation sickness is the transport delay, the delay between the action and the corresponding rendering cues. Another similarity between driving simulation and VR is need for correct scale 1:1 perception. Correct perception of speed and acceleration in driving simulation is crucial for automotive experiments for Advances Driver Aid System (ADAS) as vehicle behavior has to be simulated correctly and anywhere where the correct mental workload is an issue as real immersion and driver attention is depending on it. Correct perception of distances and object size is crucial using HMDs or CAVEs, especially as their use is frequently involving digital mockup validation for design, architecture or interior and exterior lighting. Today, the advents of high resolution 4K digital display technology allows near eye resolution stereoscopic 3D walls and integrate them in high performance CAVEs. High performance CAVEs now can be used for vehicle ergonomics, styling, interior lighting and perceived quality. The first CAVE in France, built in 2001 at Arts et Metiers ParisTech, is a 4 sided CAVE with a modifiable geometry with now traditional display technology. The latest one is Renault’s 70M 3D pixel 5 sides CAVE with 4K x 4K walls and floor and with a cluster of 20 PCs. Another equipment recently designed at Renault is the motion based CARDS driving simulator with CAVE like 4 sides display system providing full 3D immersion for the driver. The separation between driving simulation and digital mockup design review is now fading though different uses will require different simulation configurations. New application domains, such as automotive AR design, will bring combined features of VR and driving simulation technics, including CAVE like display system equipped driving simulators

Technique simplifiée et non stérile pour la culture d'embryons immatures de tournesol (Helianthus annuus)

On décrit une méthode simple ne faisant pas appel à la technique in vitro stérile pour la culture d'embryons immatures de tournesol. Ceux-ci sont directement placés sur papier filtre imbibé d'une solution nutritive commerciale puis, lorsque leurs cotylédons se sont écartés et sont devenus chlorophylliens, les embryons sont repiqués sur terreau. Toutes ces opérations sont réalisées en conditions non stériles. Les plantes obtenues sont plus vigoureuses, elles ont une production de graines accrue et un cycle complet de végétation plus court que celles issues de culture in vitro classique.Simplified and non-sterile technique for the cultivation of immature embryos of sunflower (Helianthus annuus). A simplified technique for the culture of immature embryos of sunflower (Helianthus annuus) is presented. This technique does not use the sterile in vitro method usually applied to the culture of immature sunflower embryos. Immature embryos are first placed on a filter paper imbibed with a commercial nutritive solution and then directly transferred to compost at the chlorophyllian stage of cotyledons. All these operations are achieved under non-sterile conditions. This quite simple process provides more vigorous plants, with increased seed production and a complete vegetation cycle which is shorter than that observed with the classical in vitro method

Judd-Ofelt analysis and improvement of thermal and optical properties of tellurite glasses by adding P2O5

International audienceEr3+ and Er3+/Yb3+ co-doped tellurite glasses, suitable for developing optical fiber laser and amplifier, have been elaborated from the conventional melt-quenching method. Results of differential scanning calorimetry (DSC) measurements indicate a good thermal stability of tellurite glasses. The DSC measurements show an improvement of thermal stability of glass hosts after adding P2O5. Absorption spectrum from near infrared to visible was obtained and the Judd-Ofelt (J-O) intensity parameters (Omega(2), Omega(4), and Omega(6)) were determined. Spontaneous emission probabilities of some relevant transitions, branching ratio, and radiative lifetimes of several excited states of Er3+ have been predicted using intensity J-O parameters. Absorption cross-section and calculated emission cross-section, using the McCumber method, for the I-4(13/2)-> I-4(15/2) transition, were determined and compared for the doped and co-doped glasses. Energy transfer (ET) and effect of changing concentration of P2O5 and Yb3+ ions on spectroscopic properties were investigated. It was found that the addition of P2O5 can increase the symmetry of the Er3+ ion. As a consequence, PL lifetime becomes more longer. The spectroscopic properties and the efficient infrared luminescence indicate that Er3+ doped TeO2-ZnO-Na2O-Er2O3 (TZNE) is a promising laser and amplifier materials and may be a potentially useful material for developing upconversion fiber optical devices. (C) 2010 Elsevier B.V. All rights reserved

An Effective Automated Approach to Specialization of Code

Abstract. Application performance is heavily dependent on the compiler optimizations. Modern compilers rely largely on the information made available to them at the time of compilation. In this regard, specializing the code according to input values is an effective way to communicate necessary information to the compiler. However, the static specialization suffers from possible code explosion and dynamic specialization requires runtime compilation activities that may degrade the overall performance of the application. This article proposes an automated approach for specializing code that is able to address both the problems of code size increase and the overhead of runtime activities. We first obtain optimized code through specialization performed at static compile time and then generate a template that can work for a large set of values through runtime specialization. Our experiments show significant improvement for different SPEC benchmarks on Itanium-II(IA-64) and Pentium-IV processors using icc and gcc compilers.

Studies on ion channel antagonist-binding sites in sunflower protoplasts

AbstractThe cytological location of ion channel antagonist-binding sites was studied in sunflower protoplasts using the fluorescent probes DM–Bodipy–PAA and DM–Bodipy–DHP. The binding specificity of the probes was established by competition experiments with Bepridil, phenylalkylamine (Verapamil) and dihydropyridine (Nifedipine) which are known as calcium and potassium channel antagonists. Quantitative image analysis of the fluorescence emitted by the protoplasts showed the existence of interactions between PAA- and DHP-binding sites. Moreover, studies on the cytolocalization of the PAA receptors by confocal imaging showed that in freshly isolated protoplasts, DM–Bodipy–PAA binds exclusively at sites located in the cortical region of the cell

Scheduling on Two Unbounded Resources with Communication Costs

International audienceHeterogeneous computing systems are popular and powerful platforms, containing several heterogeneous computing elements (e.g. CPU+GPU). In this work, we consider a platform with two types of machines , each containing an unbounded number of elements. We want to execute an application represented as a Directed Acyclic Graph (DAG) on this platform. Each task of the application has two possible execution times, depending on the type of machine it is executed on. In addition we consider a cost to transfer data from one platform to the other between successive tasks. We aim at minimizing the execution time of the DAG (also called makespan). We show that the problem is NP-complete for graphs of depth at least three but polynomial for graphs of depth at most two. In addition, we provide polynomial-time algorithms for some usual classes of graphs (trees, series-parallel graphs)

Effect of atmospheric pressure on sunflower (Helianthus annuus L.) protoplast division

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Synthesis and luminescence properties of vanadium-doped nanosized zinc oxide aerogel

International audienceWe report the elaboration of vanadium-doped ZnO nanoparticles prepared by a sol-gel processing technique. In our approach, the water for hydrolysis was slowly released by esterification reaction followed by a supercritical drying in ethyl alcohol. Vanadium doping concentration of 10 at% has been investigated. The obtained nanopowder was characterised by various techniques such as particle size analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and photoluminescence (PL). In the as-prepared state, the powder with an average particle size of 25 nm presents a strong luminescence band in the visible range after thermal treatment at 500 degrees C in air. The energy position of the obtained PL band depends on the wavelength excitation and presents a blue shift with measurement temperature increase. Different possible attributions of this emission band will be discussed. (c) 2007 Elsevier B.V. All rights reserved