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Smirani S.,CEA Saclay Nuclear Research Center | Kamoun M.,CEA Saclay Nuclear Research Center | Sarkiss M.,CEA Saclay Nuclear Research Center | Zaidi A.,Universiteandacute | Duhamel P.,Supelec
International Conference on Advanced Technologies for Communications | Year: 2012

A Two-Way Relay Channel (TWRC) in which duplex transmission between two users via a relay station is considered. A physical layer network coding strategy based on compress-and-forward relaying scheme for the TWRC is proposed. In the underlying coding strategy, we use nested lattices for Wyner-Ziv coding and decoding. The relay uses the weaker side information available at the receivers from the first transmission phase to broadcast a common quantized version of its received signal. We characterize the achievable rate region of the presented scheme. Then we show that lattice codes can achieve random coding rates. © 2012 IEEE. Source

Delisle G.Y.,Universiteandacute
IEEE Vehicular Technology Conference | Year: 2014

This paper presents a multi-directive antenna for point-to-multipoint line-of-sight (LOS) communications. Based on an Electromagnetic Crystal (EC) structure, the proposed antenna is able to provide several simultaneous directive beams in different directions at different frequencies. Thus by conveniently disposing the different communication points in the space and allowing them to communicate at different frequencies, a high performance network can be obtained by using a single antenna. To study the antenna performance, both theoretical analysis and numerical simulations are presented and validated by experimental results. andcopy; 2014 IEEE. Source

Meunier A.,University Pierre and Marie Curie | Bretou M.,Universiteandacute | Darchen F.,Universiteandacute | Guille Collignon M.,University Pierre and Marie Curie | And 2 more authors.
Electrochimica Acta | Year: 2014

Amperometry at ultramicroelectrodes is nowadays a routine analytical technique for quantitative real-time monitoring of vesicular exocytosis at single cell levels. The method performance and ease of application stem from the fact that it simply involves an electrochemical oxidation at a microelectrode surface of neurotransmitters released by a given cell. The exocytotic fluxes are thus converted into a current and appear as a succession of amperometric spikes, whose frequency and shapes are particularly informative about the dynamics of the release process, while their integrals give a direct measure of the quantity of molecules released. In this article, we wish to evaluate and describe the amperometric detection of exocytotic release by BON cells, a cell line derived from a metastatic human carcinoid tumor of the pancreas and recently involved in combined approaches of exocytosis (particularly fluorescence/electrochemistry). The whole exocytotic activity (frequency, spike magnitude) of BON cells is rather weak by comparison with those observed with others cell models like chromaffin cells but remain suitable for amperometric investigations. andcopy; 2013 Elsevier Ltd.©2013 Elsevier Ltd. All rights reserved. Source

Razakamanarivo R.H.,Universiteandacute | Grinand C.,Montpellier SupAgro | Razafindrakoto M.A.,Universiteandacute | Bernoux M.,Montpellier SupAgro | Albrecht A.,Montpellier SupAgro
Geoderma | Year: 2011

Recent concerns about global warming have resulted in more concerted studies on quantification and modeling of carbon (C) storage in different ecosystems. The aim of this study was to assess and map the carbon stocks in above (ABG), below-ground (BLG) biomass and soil organic carbon contained in the 30centimeter top-layer (SOC) in coppices of eucalyptus plantations in the central highlands of Madagascar in an area of 1590ha. Relationships between C stock and various biophysical (stool or shoot stockings and ages, circumferences) and spatial (elevation, slope, and soil type) factors that may affect C storage within each pool were investigated. Three different modeling techniques were tested and compared for various factor sets: (i) simple linear regression (SLM), (ii) multiple linear (MLM) models and, (iii) boosted regression tree (BRT) models. Weights of the factors in the respective model were analyzed for the three pool-specific models that produced the highest accuracy measurement. A regional spatial prediction of carbon stocks was performed using spatial layers derived from a digital elevation model, remote sensing imagery and expert knowledge. Results showed that BRT had the best predictive capacity for C stocks compared with the linear regression models. Elevation and slope were found to be the most relevant predictors for modeling C stock in each pool, and mainly for the SOC. A factor representing circumferences of stools and their stocking (stools.ha-1) largely influenced BLG. Shoot circumference at breast height and shoot age were the best factors for ABG fitting. Accuracy assessment carried out using coefficient of determination (R2) and ratio of standard deviation to prediction error (RPD) showed satisfactory results, with 0.74 and 1.95 for AGB, 0.85 and 2.59 for BLG, and 0.61 and 1.6 for SOC respectively. Application of the best fitted models with spatial explanatory factors allowed to map and estimate C contained within each pool: 32andplusmn;13Gg C for ABG, 67andplusmn;15Gg C for BLG and, 139andplusmn;36Gg C for SOC (1Gg=109g). A total of 238andplusmn;40Gg C was obtained for the entire study area by combining the three C maps. Despite their relatively low predictive quality, models and C maps produced herein provided relevant reference values of C storage under plantation ecosystems in Madagascar. This study contributed to the reducing of uncertainty related to C monitoring and baseline definition in managed terrestrial ecosystem. andcopy; 2011 Elsevier B.V. Source

Desrochers N.,Universiteandacute | Laplante A.,Universiteandacute | Quan-Haase A.,University of Western Ontario | Martin K.,University of Western Ontario | And 2 more authors.
Proceedings of the ASIST Annual Meeting | Year: 2013

Social tagging has become a common practice across a variety of platforms on the Web. In this panel, we propose to start with one title, Casino Royale, a James Bond novel by Ian Fleming, and the other cultural products that emanated from it (e.g., two movies, one song, visuals and images, articles and blog posts) to explore social tagging practices and other user-generated content in a variety of different platforms. Goodreads, Last.fm, WordPress, Flickr and various library discovery systems will be used to expose the connections users establish between and among cultural products as well as to compare what tagging yields in different platforms. The results will be situated within the context of broader studies being performed by the panelists and audience members will be asked to contribute material for real-time searches. Source

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