Flat Bidirectional Texture Functions

Highly-realistic materials in computer graphics are computationally and memory demanding. Currently, the most versatile techniques are based on Bidirectional Texture Functions (BTFs), an image-based approximation of appearance. Extremely realistic images may be quickly obtained with BTFs at the price of a huge amount of data. Even though a lot of BTF compression schemes have been introduced during the last years, the main remaining challenge arises from the fact that a BTF embeds many different optical phenomena generated by the underlying meso-geometry (parallax effects, masking, shadow casting, inter-reflections, etc.). We introduce a new representation for BTFs that isolates parallax effects. On one hand, we built a flattened BTF according to a global spatial parameterization of the underlying meso-geometry. On the other hand, we generate a set of view-dependent indirection maps on this spatial parameterization to encode all the parallax effects. We further analyze this representation on a various set of synthetic BTF data to show its benefits on view-dependent coherency, and to find the best sampling strategy. We also demonstrate that this representation is well suited for hardware acceleration on current GPUs.En Infographie, les matériaux hautement réalistes sont grand consommateurs de puissance de calculs ainsi que de mémoire. A l'heure actuelle, les techniques les plus versatiles reposent sur les fonctions de textures bidirectionnelles (BTFs) représentant une approximation à partir d'images de l'apparence des matériaux. Des images extrêmement réalistes peuvent être obtenues rapidement à l'aide de BTFs au prix d'une énorme quantité de données. Bien que de nombreux schémas de compression de BTFs aient été introduits au cours de ces dernières années, le principal challenge restant provient du fait qu'une BTF mélange différents phénomènes optiques générés par la meso-géométrie sous-jacente (effets de parallaxe ou de masquage, ombres portées, inter-réflexions, etc.), effets qui ne peuvent être que correctement gérés à l'aide d'approches appropriées. Nous introduisons une nouvelle représentation pour les BTFs qui isole les effets de parallaxes des autres effets. D'une part, nous construisons une BTF aplatie ("flattened") guidée par une paramétrisation spatiale et globale de la méso-géométrie sous-jacente. D'autre part, nous générons un ensemble de table d'indirections dans cette paramétrisation et pour chaque point de vue, afin d(encoder tous les effets de parallaxe. Nous analysons aussi cette représentation sur un ensemble de BTFs synthétiques afin de montrer l'avantage qu'elle apporte pour la cohérence dépendante du point de vue et pour trouver la meilleure stratégie d'échantillonnage. Nous montrons aussi que cette représentation est particulièrement bien adaptée pour bénéficier de l'accélération matérielle des processeurs graphiques actuels

AJTEC2011-44554 Fabrication of Thermoelectric La 0.95 Sr 0.05 CoO 3 Thin Film and Seebeck Coefficient Measurement

ABSTRACT The P-type perovskite oxides La 1-x Sr x CoO 3 are a promising group of complex oxide thermoelectric (TE) materials because of its a higher Seebeck coefficient. In this paper, the La 0.95 Sr 0.05 CoO 3 thin film was prepared by spin coating. A custom-made MEMS (micro-electromechanical system) based device was used to measure the voltage output and Seebeck coefficient of the thin film. The measured Seebeck coefficient of the thin film was 350 μV/K

Echantillonnage anisotropique et rendu par points différentiels pour les surfaces implicites

Dans cet article, nous proposons une solution adaptant aux surfaces implicites, le rendu par points différentiels ("differential point rendering") de Kalaiah et Varshney [KV01] originellement développé pour les surfaces paramétriques et les maillages triangulaires. La principale difficulté pour cette adaptation est que les deux étapes du processus d'échantillonnage proposé dans [KV01] s'appuient fortement sur des relations de voisinage entre les échantillons, voisinage qui n'existe pas naturellement pour les surfaces implicites. Pour résoudre ce problème, nous proposons d'étudier les possibilités d'extensions de la technique d'échantillonnage par particules de Witkin et Heckbert [WH94] afin de prendre en compte les directions et les valeurs des courbures principales de la surface implicite. Ainsi, nous présenterons des résultats provenant d'une utilisation de particules ellipsoïdales ainsi que les problèmes inhérents à la nature même de l'ellipsoïde. Puis nous proposerons de nouvelles directions de recherche dans le but de résoudre ces problèmes

On-the-fly Appearance Quantization on GPU for 3D Broadcasting

International audienceThis paper presents an improved client-server system that increases the availability of remote 3D data. In order to reduce the required bandwidth, the data related to the appearance (color and normal) involved in the rendering of meshes and point clouds is quantized on-the-fly during the transmission to the final client, without reducing the geometric complexity. Our new quantization technique for the appearance that can be implemented on the GPU, strongly reduces the CPU load on the server-side and the transmission time is largely decreased

SOMM: A New Service Oriented Middleware for Generic Wireless Multimedia Sensor Networks Based on Code Mobility

Although much research in the area of Wireless Multimedia Sensor Networks (WMSNs) has been done in recent years, the programming of sensor nodes is still time-consuming and tedious. It requires expertise in low-level programming, mainly because of the use of resource constrained hardware and also the low level API provided by current operating systems. The code of the resulting systems has typically no clear separation between application and system logic. This minimizes the possibility of reusing code and often leads to the necessity of major changes when the underlying platform is changed. In this paper, we present a service oriented middleware named SOMM to support application development for WMSNs. The main goal of SOMM is to enable the development of modifiable and scalable WMSN applications. A network which uses the SOMM is capable of providing multiple services to multiple clients at the same time with the specified Quality of Service (QoS). SOMM uses a virtual machine with the ability to support mobile agents. Services in SOMM are provided by mobile agents and SOMM also provides a t space on each node which agents can use to communicate with each other

Laboratory Studies of Air Stripping of VOC-Contaminated Soils

ABSTRACT: Bench-scale laboratory experiments were conducted to evaluate the effectiveness of air stripping for in situ remediation of benzene-contaminated soils. Several parametric studies were performed to evaluate the effect of soil grain size, air injection flow rate, and air inlet temperature on the benzene recovery efficiency. An increase in soil grain size produced a significant increase in benzene recovery efficiency especially during the early stages of air injection. After 2 h of treatment, an increase in soil grain size from D 50 = 0.31 mm to D 50 = 1.20 mm resulted in an increase in benzene recovery efficiency from 49 to 65%. When the air-flow rate was increased from 5 l/min to 10 l/min, the benzene recovery efficiency increased from 56 to 70% after 4 h of venting operation. Maximum recovery of benzene was reached after approximately 37 h of soil venting at a flow rate of 5 l/min and after approximately 24 h at a flow rate of 10 l/min. Preheating the air to 45°C at the inlet resulted in an increase in recovery efficiency from 70 to 90% after 5 h of air stripping

On the Relevance of Using Open Wireless Sensor Networks in Environment Monitoring

This paper revisits the problem of the readiness for field deployments of wireless sensor networks by assessing the relevance of using Open Hardware and Software motes for environment monitoring. We propose a new prototype wireless sensor network that fine-tunes SquidBee motes to improve the life-time and sensing performance of an environment monitoring system that measures temperature, humidity and luminosity. Building upon two outdoor sensing scenarios, we evaluate the performance of the newly proposed energy-aware prototype solution in terms of link quality when expressed by the Received Signal Strength, Packet Loss and the battery lifetime. The experimental results reveal the relevance of using the Open Hardware and Software motes when setting up outdoor wireless sensor networks

Implementing and operationalising integrative approaches to sustainability in Higher Education: The role of project-oriented learning.

Higher education institutions across the world are increasingly placing an emphasis on students’ acquisition of a broader range of skills or attributes within the taught curriculum, which should lead to a widening of their chances of academic success, in particular in the employment market. Among other issues, matters related to sustainable development are playing a key role, but many universities do not yet cater for integrative approaches, which may help them to approach sustainability issues in a transformative way. It is therefore necessary to develop new approaches and methods, which may address this gap. Based on the importance of meeting this perceived research need, this paper defines the role of project-oriented learning, also designated as Project Based Learning, as a tool to support integrative approaches to sustainability in a higher education context. The scientific value of the paper lies in the provision of some examples of successful approaches to Project Based Learning and the identification of some of the trends that characterise it. The paper makes clear why project-oriented learning should be more widely used in support of integrative approaches to sustainability, and why it needs to become part of the routine of higher education institutions. The outline of some of the initiatives recently and currently being undertaken may inspire others and assist in the implementation of Project Based Learning

Morphological variation within Salvinia molesta D. S. Mitchell (Salviniaceae) populations in the Kinabatangan, Sabah

This study aimed to understand the principle of variation within the same species of plant, though it grew in a narrow environmental gradient area, such as the tropic. An aquatic fern species and has the potential to become a weed in the Sabah freshwater ecosystem was chose for this study: Salvinia molesta D. S Mitchell. Taxonomical and ecological informations of this species in Sabah were still at the initial stage and very limited. The Lower Kinabatangan River is the place when it was first recorded and became the focus area in this study. Samples of S. molesta from twelve stations along the Lower Kinabatangan River and three comparison stations from the Sandakan inland were analyzed to determine morphological differences between: quadrates (within the same population), between populations (from different stations), and between two types of water bodies (open and closed water bodies). By considering the maximum level of individual's maturity stage, the statistical analysis of One-way ANOVA and t-test were used to compare the means of morphometric measurements and meristic counts on six quantitative characters of this species. The quantitative characters were from the vegetative structure (floating leaf length and width, submerged leaf length, rhizome diameter) and reproductive structure (number of fertile axis, number of sporocarps). All the samples analyzed showed that there were morphological differences within the S. molesta populations in the study area. Variation between quadrates was significant (p<0.001) within the S. molesta populations with the size of more than five meter square. Variation between populations along the Kinabatangan River resulted with a highly significant (p<0.001) morphological differences from one stations to another. Morphological differences for samples from the two type of water bodies (open and closed water bodies) were also showed a highly significant (p<0.001) different; samples from the open water body were bigger in sizes of leaves and rhizome. Based on regression and correlation analysis, relationship between the quantitative characters were positive and significant (p<0.01). However, regression between the characters and the stations positioned showed that the plants were bigger at the upper stream area. The cluster analysis of Ward's method showed samples from the Sg. Koyah was a distinctive group among others. No consistent morphological characters can be used to distinguish between intraspecific populations of this species. The data obtained from this present study agrees with the hypothesis that there was an intraspecific variation occurred within the S. molesta populations in the Kinabatangan and rejected the null hypothesis. This study also added evidence on S. molesta as a single species of a highly morphological variability even in a narrow environmental gradient area, such as the tropic