An Energy Efficient Self-healing Mechanism for Long Life Wireless Sensor Networks

In this paper, we provide an energy efficient self- healing mechanism for Wireless Sensor Networks. The proposed solution is based on our probabilistic sentinel scheme. To reduce energy consumption while maintaining good connectivity between sentinel nodes, we compose our solution on two main concepts, node adaptation and link adaptation. The first algorithm uses node adaptation technique and permits to distributively schedule nodes activities and select a minimum subset of active nodes (sentry) to monitor the interest region. And secondly, we in- troduce a link control algorithm to ensure better connectiv- ity between sentinel nodes while avoiding outliers appearance. Without increasing control messages overhead, performances evaluations show that our solution is scalable with a steady energy consumption. Simulations carried out also show that the proposed mechanism ensures good connectivity between sentry nodes while considerably reducing the total energy spent.Comment: 6 pages, 8 figures. arXiv admin note: text overlap with arXiv:1309.600

Note on a new Seasonal Fractionally Integrated Separable Spatial Autoregressive Model

URL des Documents de travail : http://ces.univ-paris1.fr/cesdp/cesdp2016.htmlDocuments de travail du Centre d'Economie de la Sorbonne 2016.13 - ISSN : 1955-611XIn this paper, we introduce a new model called Fractionally Integrated Separable Spatial Autoregressive processes with Seasonality and denoted Seasonal FISSAR for two-dimensional spatial data. We focus on the class of separable spatial models whose correlation structure can be expressed as a product of correlations. This new modelling allows taking into account the seasonality patterns observed in spatial data. We investigate the properties of this new model providing stationary conditions, some explicit expressions form of the autocovariance function and the spectral density function. We establish the asymptotic behaviour of the spectral density function near the seasonal frequencies and perform some simulations to illustrate the behaviour of the model

L’élection présidentielle de février 2019 au Sénégal

L’article analyse l’élection présidentielle de février 2019 au Sénégal. Il décrit le contexte pré-électoral et met l’accent sur le processus et les résultats du scrutin avec en retour un regard sur les implications du contexte de déroulement. L’analyse combine deux approches méthodologiques : une approche interprétative fondée sur l’observation du contexte et une approche descriptive qui s’appuie sur le recueil et la cartographie des données statistiques publiées par le Conseil constitutionnel du Sénégal. Les résultats de l’étude montrent que l’élection présidentielle et son contexte ont été marqués par une crise politico-judiciaire qui a favorisé une reconfiguration du paysage politique avec la disparition de la compétition de partis historiques et l’émergence d’une nouvelle figure politique, chantre de l’« antisystème ». Même si le candidat du parti au pouvoir a été reconduit, les résultats du vote n’ont pas montré de grandes disparités géographiques entre le pouvoir et l’opposition réunie. Convaincue d’un équilibre territorial des rapports de force au moment du vote, l’opposition l’est encore plus par l’existence de « territoires conquis », ce qui présageait une crise postélectorale. De plus, le vote régional ou le régionalisme électoral tout comme la prise de position partisane des médias ont été des aspects essentiels de cette élection.The article analyzes the presidential election of February 2019 in Senegal. It describes the pre-election context and focuses on the process and results of the polls with a look back at the implications of the unfolding context. The analysis combines two methodological approaches: an interpretative approach based on context observation and a descriptive approach based on the collection and mapping of statistical data published by the Constitutional Council of Senegal. The results of the study show that the presidential election and its context were marked by a politico-judicial crisis that favored a reconfiguration of the political landscape with the disappearance of the competition of historical parties and the emergence of a new political figure which is the forerunner of the "antisystem". Although the ruling party's candidate was renewed, the results of the vote did not show large geographical disparities between the power and the opposition. Convinced of a territorial balance of power in the vote, the opposition is more by the existence of "conquered territories", which foreshadowed a post-election crisis. In addition, the regional vote or electoral regionalism as well as the partisan position of the media were essential aspects of this election

Dietary Intakes and Nutritional Status of Mother-Child (6-23 Months Old) Pair Targeted through the "Organic Residual Products for Biofortified Foods for Africa Project" in Rural Area in Senegal

Background: Despite micronutrient supplementation and food fortification strategies carried out for decades, micronutrient deficiencies remain prevalent among children under 5 years old in rural area in Senegal. The OR4FOOD project was implemented as a preventive and long-term approach to reduce malnutrition through biofortification. Objective: We aimed to assess the baseline dietary intakes and nutritional status of the mother-child (6-23 months old) pair in a rural community in Senegal. Methods: Dietary intakes were assessed using dietary recall questionnaires and weight food records. All foods and beverages consumed from waking to bedtime were quantified, and nutrient intakes were calculated. The nutritional status was measured by anthropometry. Results: Results showed that 77.2% of children had low dietary diversity score. Only 18% of them received an appropriate complementary feeding according to the minimum acceptable diet. Cereals and legumes were among the most consumed food groups, whereas orange-fleshed sweet potato (OFSP) and animal food products were rarely consumed. Median dietary intakes of iron, zinc, and vitamin A were lower than the recommended dietary allowances. Acute malnutrition and stunting affected 14.6% and 16.9% of children, respectively. Overall, 20.8% of mothers were underweighted, and overweight/obesity affected 23.1% of them. Conclusion: Malnutrition remains prevalent in rural areas of Senegal and affects both mothers and children. Furthermore, their nutrient requirements were not covered by the diet. Millet and cowpea being widely consumed, optimizing their iron and zinc content through biofortification and the introduction of OFSP might improve micronutrient intakes and would be promising strategies to prevent child malnutrition

Evolution of Surface Hydrology in the Sahelo-Sudanian Strip: An Updated Review

In the West African Sahel, two paradoxical hydrological behaviors have occurred during the last five decades. The first paradox was observed during the 1968–1990s ‘Great Drought’ period, during which runoff significantly increased. The second paradox appeared during the subsequent period of rainfall recovery (i.e., since the 1990s), during which the runoff coefficient continued to increase despite the general re-greening of the Sahel. This paper reviews and synthesizes the literature on the drivers of these paradoxical behaviors, focusing on recent works in the West African Sahelo/Sudanian strip, and upscaling the hydrological processes through an analysis of recent data from two representative areas of this region. This paper helps better determine the respective roles played by Land Use/Land Cover Changes (LULCC), the evolution of rainfall intensity and the occurrence of extreme rainfall events in these hydrological paradoxes. Both the literature review and recent data converge in indicating that the first Sahelian hydrological paradox was mostly driven by LULCC, while the second paradox has been caused by both LULCC and climate evolution, mainly the recent increase in rainfall intensity

Ex vivo susceptibility and genotyping of Plasmodium falciparum isolates from Pikine, Senegal

Background: The monitoring of Plasmodium falciparum sensitivity to anti-malarial drugs is a necessity for effective case management of malaria. This species is characterized by a strong resistance to anti-malarial drugs. In Senegal, the first cases of chloroquine resistance were reported in the Dakar region in 1988 with nearly 7% population prevalence, reaching 47% by 1990. It is in this context that sulfadoxine–pyrimethamine temporarily replaced chloroquine as first line treatment in 2003, pending the introduction of artemisinin-based combination therapy in 2006. The purpose of this study is to assess the ex vivo sensitivity to different anti-malarial drugs of the P. falciparum population from Pikine. Methods: Fifty-four samples were collected from patients with non-complicated malaria and aged between 2 and 20 years in the Deggo health centre in Pikine in 2014. An assay in which parasites are stained with 4′, 6-di-amidino-2-phenylindole (DAPI), was used to study the ex vivo sensitivity of isolates to chloroquine, amodiaquine, piperaquine, pyrimethamine, and dihydroartemisinin. High resolution melting was used for genotyping of pfdhps, pfdhfr, pfmdr1, and pfcrt genes. Results: The mean IC50s of chloroquine, amodiaquine, piperaquine, dihydroartemisinin, and pyrimethamine were, respectively, 39.44, 54.02, 15.28, 2.23, and 64.70 nM. Resistance mutations in pfdhfr gene, in codon 437 of pfdhps gene, and an absence of mutation at position 540 of pfdhps were observed. Mutations in codons K76T of pfcrt and N86Y of pfmdr1 were observed at 51 and 11% population prevalence, respectively. A relationship was found between the K76T and N86Y mutations and ex vivo resistance to chloroquine. Conclusion: An increase in sensitivity of isolates to chloroquine was observed. A high sensitivity to dihydroartemisinin was observed; whereas, a decrease in sensitivity to pyrimethamine was observed in the parasite population from Pikine

Statistical properties of the seasonal fractionally integrated separable spatial autoregressive model

In this paper we introduce a new model called Fractionally Integrated Separable Spatial Autoregressive processes with Seasonality and denoted Seasonal FISSAR. We focus on the class of separable spatial models whose correlation structure can be expressed as a product of correlations. This new modelling allows taking into account the seasonality patterns observed in spatial data. We investigate the properties of this new model providing stationary conditions, some explicit form of the autocovariance function and the spectral density. We also establish the asymptotic behaviour of the spectral density function near the seasonal frequencies.Keywords: Seasonality; Spatial short memory; Seasonal long memory; Two dimensional data; Separable process; Spatial stationary process; Spatial autocovarianc

Statistical properties of the seasonal fractionally integrated separable spatial autoregressive model

International audienceIn this paper we introduce a new model called Fractionally Integrated Separable Spatial Autoregressive processes with Seasonality and denoted Seasonal FISSAR. We focus on the class of separable spatial models whose correlation structure can be expressed as a product of correlations. This new modelling allows taking into account the seasonality patterns observed in spatial data. We investigate the properties of this new model providing stationary conditions, some explicit form of the autocovariance function and the spectral density. We also establish the asymptotic behaviour of the spectral density function near the seasonal frequencies