General Approach for the Sensitivity Analysis and Optimization of Integrated Optical Evanescent-Wave Sensors

The optimization of integrated optical evanescent-wave sensors is dual. For optimal performances, we require waveguides with both maximal sensitivity to the measurand, the quantity intended to be measured, and minimal sensitivities to perturbations. In this context, fully numerical approaches are extremely powerful, but demand huge computer resources. We address this issue by introducing a general and efficient approach, based on the formal derivation of analytical dispersion equations, to express and evaluate all waveguide sensitivities. In particular, we apply this approach to rectangular waveguides, to discuss its accuracy and its use within sensitivity optimization procedures

Application of PCR-DGGE in determining food origin : cases studies of fish and fruits

The determination of geographical origin is a demand of the traceability system of import-export food products. For this purpose, molecular techniques employing 16S, 26S rDNA profiles generated by PCR-DGGE (polymerase chain reaction - denaturing gradient gel electrophoresis) were used to detect the variation in microbial community (bacteria, yeast) structures of Pangasius fish from Viet Nam harvested in different aquaculture farms and during different seasons and two fruits Physalis from Egypt and mandarins from Spain and Morocco. In Physalis case, ecology of yeasts was also studied for the same purpose. Bacterial band profiles of fish and mandarins, and yeast band profiles of Physalis were specific for each location and could be used as a bar code to certify the origin of fish and fruits. This method is a new traceability tool which provides food with a unique biological bar code and makes it possible to trace back the food to their original location. (Résumé d'auteur

Evaluation of an End-to-End Delay Estimation in the Case of Multiple Flows in SDN Networks

International audienceThough SDN (Software Defined Network) provides the executive building blocks for programming data-plane appliances , controller decisions must be grounded in an accurate outlook on the network topology and performance. In this context, we focus on the possibility of providing accurate measurements for the end-to-end (E2E) delay in SDN networks. In practice, like many variable quantities, a good description of the E2E delay requires characterizing its first two moments, i.e., expectation and variance. We propose to estimate the E2E delay by making use only of measurements collected locally on each node of the network. We extend a procedure that has been proposed to estimate the E2E delay in the case of one flow to handle the case of multiple competing flows. We compare its accuracy using several scenarios, with different types of traffic following real traces, different topologies and bandwidth. Also, an analysis of the computational and networking costs of our solution is proposed

Cache-Conscious Offline Real-Time Task Scheduling for Multi-Core Processors

Most schedulability analysis techniques for multi-core architectures assume a single Worst-Case Execution Time (WCET) per task, which is valid in all execution conditions. This assumption is too pessimistic for parallel applications running on multi-core architectures with local instruction or data caches, for which the WCET of a task depends on the cache contents at the beginning of its execution, itself depending on the task that was executed before the task under study. In this paper, we propose two scheduling techniques for multi-core architectures equipped with local instruction and data caches. The two techniques schedule a parallel application modeled as a task graph, and generate a static partitioned non-preemptive schedule. We propose an optimal method, using an Integer Linear Programming (ILP) formulation, as well as a heuristic method based on list scheduling. Experimental results show that by taking into account the effect of private caches on tasks\u27 WCETs, the length of generated schedules is significantly reduced as compared to schedules generated by cache-unaware scheduling methods. The observed schedule length reduction on streaming applications is 11% on average for the optimal method and 9% on average for the heuristic method

Evaluation of an End-to-End Delay Estimation in the Case of Multiple Flows in SDN Networks

International audienceThough SDN (Software Defined Network) provides the executive building blocks for programming data-plane appliances , controller decisions must be grounded in an accurate outlook on the network topology and performance. In this context, we focus on the possibility of providing accurate measurements for the end-to-end (E2E) delay in SDN networks. In practice, like many variable quantities, a good description of the E2E delay requires characterizing its first two moments, i.e., expectation and variance. We propose to estimate the E2E delay by making use only of measurements collected locally on each node of the network. We extend a procedure that has been proposed to estimate the E2E delay in the case of one flow to handle the case of multiple competing flows. We compare its accuracy using several scenarios, with different types of traffic following real traces, different topologies and bandwidth. Also, an analysis of the computational and networking costs of our solution is proposed

Characterisation and Application of Idle Period Durations in IEEE 802.11 DCF-based Multihop Wireless Networks

International audienceMultihop wireless networks are used to provide internet connectivity to the users and the level of performance and quality expected by these users are increasing. In order to meet these performance and quality requirements, wireless communications should be enhanced. Previous works from the literature show that the performance and quality provided by an IEEE 802.11-based multihop wireless network are far from optimal and that there exist di erent ways to increase the e ciency and the quality of service of such a network. Some studies show that using the medium state as a param- eter to tune the behaviour of an IEEE 802.11-based multi-hop network is an appropriate way to proceed. A station in a IEEE 802.11-based multihop wireless network senses the medium either busy or idle. The durations of idle periods and busy periods and their distributions have a clear impact on the network and nodes performance. The understanding of the relationship between these indicators, namely idle and busy periods, the network topology and the tra c, would give new insights to enhance the performance and quality of multihop wireless networks. Due to its multihop and distributed nature, the characterisation of idle period durations is di cult in such a network. This paper explores the characterisation of idle period distribution by proposing a new analytical model and provides an application of this characterisation with the design of an adaptive backo algorithm based on idle periods

Экологические проблемы информационной цивилизации

Цель данного исследования - проясниться характерные черты академического взгляда, подготовленные революцией в информационной сфере. Задача, установленная автором, рассмотреть возможные проблемы, которые создает информационная цивилизация. Методологической основой для достижения поставленных целей и решения проблем является систематический подход.The purpose of this study is to clarify the features of the scientific worldview prepared by the information revolution. The task posed by the author lies in the field of considering possible problems created by the information civilization. The methodological basis for achieving the goals and solutions of the assigned task is the system-activity approach

Nouvelles stratégies de traçabilité pour déterminer l'origine géographique des fruits : création d'un code barre biologique par PCR-DGGE

La détermination de l'origine géographique est une demande du système de traçabilité des denrées alimentaires d'import-export. Une hypothèse de retrouver la source d'un produit est en analysant de façon globale les communautés microbiennes de la nourriture et des liens statistiquement cette analyse à l'origine géographique des produits alimentaires (Montet et al., 2004). La technique moléculaire employant rADN 26S profils générés par PCR-DGGE a été utilisée pour détecter la variation dans les structures communautaires de levure de fruits (El Sheikha et al., 2009). Nous avons appliqué cette nouvelle technique sur des fruits Physalis de trois pays (Égypte, Colombie, Ouganda) et sur le karité à partir de quatre pays (Cameroun, Mali, Sénégal, Ouganda). Les gels DGGE ont montré des différences significatives dans les schémas de migration. Toutefois, les doublons pour chaque point d'échantillonnage donne statistiquement les modèles DGGE similaires à travers l'étude. Nous avons démontré qu'il y avait un lien entre les populations de levures et l'aire géographique. Lorsque rADN 26S des profils ont été analysés par analyse multivariée, distinct des communautés microbiennes ont été détectés. Les profils de bande de différents pays étaient différentes et sont spécifiques pour chaque pays et pourrait être utilisé comme un code-barres de discriminer l'origine des fruits. Cette méthode est un outil de traçabilité qui offre de nouveaux produits fruitiers avec un code-barre unique et permet de retracer les fruits dans leur pays d'origine. Physalis est inclus dans la liste prioritaire de l'horticulture de nombreux gouvernements et d'exportation de fruits. Il est exporté dans plusieurs pays comme la Colombie, l'Egypte, le Zimbabwe et l'Afrique du Sud, mais la Colombie se distingue comme l'un des plus grands producteurs, consommateurs et exportateurs. Les exportations de la Colombie de Physalis en 2004 ont une valeur de 14 millions d'USD (El Sheikha et al., 2008a). En Egypte, l'importance économique de Physalis est en hausse, en raison, la réalisation d'un grand succès en arabe local, et les marchés européens (El Sheikha, 2004). Physalis que la plante a de nombreuses propriétés médicinales, y compris les antipyrétiques, dépuratif, diurétique, pectoral, et vermifuge. Une décoction est utilisée dans le traitement des abcès, toux, fièvre ou mal de gorge (Duke et Ayensu 1985). La pulpe est nutritif, contenant des niveaux particulièrement élevés de caroténoïdes, des minéraux, acides aminés essentiels et en vitamine C (El Sheikha et al., 2008b). En ce qui concerne les fruits des arbres de karité, seuls sept pays ont des statistiques. Nigeria compte plus de 60% de la production de beurre de karité en 2005. Il est suivi par le Mali, le Ghana et le Burkina Faso, qui représentent ensemble un peu moins du tiers de la production mondiale en 2005. En Europe, le beurre de karité est utilisé principalement (95%) par l'industrie du chocolat. Les quantités exportées vers le Japon, les États-Unis ou la Suisse serait principalement utilisé pour les cosmétiques ou pharmacologiques (FAOSTAT, 2007). (Texte intégral

Methodological framework for a participatory study to evaluate the socio-economic factors impairing the efficacy of animal health surveillance systems

The need to set up efficient, sustainable surveillance networks of animal diseases is a major issue for worldwide animal and public health management. In developing countries the need to assess the efficiency and sustainability of surveillance systems is of primary importance because of major sanitary issues and limited economic resources. So far, only the economic component of the sustainability concept has been subject to scientific interest, leaving out the social aspects. We present here a methodological framework for an assessment of social and economic issues faced by local actors involved in surveillance systems. This multidisciplinary approach consists of two major steps: first, the identification of the pathways of sanitary information diffusion through formal and informal social networks, and second the characterization of the socio-economic factors involved in these information sharing behaviors. Two methodologies can be implemented to develop models of the social network involved in sanitary information flow: (1) individual structured interviews based on prior identification of the actors involved; and (2) participatory methods, including observation and workshops. The development of the two models allows for comparison between their outcomes and their respective relevance. Stated preference methods, widely used in the field of economics to assess non-market values can then be applied to identify and quantify the social goods at stake in sanitary information flow. Due to the social and interactive nature of the targeted decision-making, stated preferences were elicited using participatory tools as well as role-playing games. (Texte intégral