Fiabilisation des transmissions dans les réseaux de capteurs sans fils

Over the past decades, we have witnessed a proliferation of potential application domainsfor wireless sensor networks (WSN). A comprehensive number of new services such asenvironment monitoring, target tracking, military surveillance and healthcare applicationshave arisen. These networked sensors are usually deployed randomly and left unattendedto perform their mission properly and efficiently. Meanwhile, sensors have to operate ina constrained environment with functional and operational challenges mainly related toresource limitations (energy supply, scarce computational abilities...) and to the noisyreal world of deployment. This harsh environment can cause packet loss or node failurewhich hamper the network activity. Thus, continuous delivery of data requires reliabledata transmission and adaptability to the dynamic environment. Ensuring network reliabilityis consequently a key concern in WSNs and it is even more important in emergencyapplication such disaster management application where reliable data delivery is the keysuccess factor. The main objective of this thesis is to design a reliable end to end solution for data transmission fulfilling the requirements of the constrained WSNs. We tackle two design issues namely recovery from node failure and packet losses and propose solutions to enhance the network reliability. We start by studying WSNs features with a focus on technical challenges and techniques of reliability in order to identify the open issues. Based on this study, we propose a scalable and distributed approach for network recovery from nodefailures in WSNs called CoMN2. Then, we present a lightweight mechanism for packetloss recovery and route quality awareness in WSNs called AJIA. This protocol exploitsthe overhearing feature characterizing the wireless channels as an implicit acknowledgment(ACK) mechanism. In addition, the protocol allows for an adaptive selection of therouting path by achieving required retransmissions on the most reliable link. We provethat AJIA outperforms its competitor AODV in term of delivery ratio in different channelconditions. Thereafter, we present ARRP, a variant of AJIA, combining the strengthsof retransmissions, node collaboration and Forward Error Correction (FEC) in order toprovide a reliable packet loss recovery scheme. We verify the efficiency of ARRP throughextensive simulations which proved its high reliability in comparison to its competitor.Vu les perspectives qu'ils offrent, les réseaux de capteur sans fil (RCSF) ont perçu un grand engouement de la part de la communauté de recherche ces dernières années. Les RCSF couvrent une large gamme d'applications variant du contrôle d'environnement, le pistage de cible aux applications de santé. Les RCSFs sont souvent déployés aléatoirement. Ce dispersement des capteurs nécessite que les protocoles de transmission utilisés soient résistants aux conditions environnementales (fortes chaleurs ou pluies par exemple) et aux limitations de ressources des nœuds capteurs. En effet, la perte de plusieurs nœuds capteurs peut engendrer la perte de communication entre les différentes entités. Ces limitations peuvent causer la perte des paquets transmis ce qui entrave l'activité du réseau. Par conséquent, il est important d'assurer la fiabilité des transmissions de données dans les RCSF d'autant plus pour les applications critiques comme la détection d'incendies. Dans cette thèse, nous proposons une solution complète de transmission de données dans les RCSF répondant aux exigences et contraintes de ce type de réseau. Dans un premier temps, nous étudions les contraintes et les challenges liés à la fiabilisation des transmissions dans les RCSFs et nous examinons les travaux proposés dans la littérature. Suite à cette étude nous proposons COMN2, une approche distribuée et scalable permettant de faire face à la défaillance des nœuds. Ensuite, nous proposons un mécanisme de contrôle d'erreur minimisant la perte de paquets et proposant un routage adaptatif en fonction de la qualité du lien. Cette solution est basée sur des acquittements implicites (overhearing) pour la détection des pertes des paquets. Nous proposons ensuite ARRP une variante de AJIA combinant les avantages des retransmissions, de la collaboration des nœuds et des FEC. Enfin, nous simulons ces différentes solutions et vérifions leurs performances par rapport à leurs concurrents de l'état de l'art

Adaptive Reliable Routing Protocol for Wireless Sensor Networks

International audienceMany Wireless Sensor Networks (WSN) applications success is contingent upon the reliable delivery of high-priority events from many scattered sensors to one or more sink nodes. In particular, WSN has to be self-adaptive and resilient to errors by providing efficient mechanisms for information distribution especially in the multi-hop scenario. To meet the stringent requirement of reliably transmitting data, we propose a lightweight and energy-efficient joint mechanism for packet loss recovery and route quality awareness in WSNs. In this protocol, we use the overhearing feature characterizing the wireless channels as an implicit acknowledgment (ACK) mechanism. In addition, the protocol allows for an adaptive selection of the routing path, based on a collective cooperation within neighborhood

Fast restoration of Connectivity for Wireless Sensor Networks

International audienceNode failures represent a fundamental problem in wireless sensor networks. Such failures may result in partitioned networks and lose of sensed information. A network recovery approach is thus necessary in order to ensure continuous network operations. In this paper, we propose CoMN2 a scalable and distributed approach for network recovery from node failures in wireless sensor networks. CoMN2 relies on a new concept called network mapping which consists in partitioning the network into several regions of increasing criticality. The criticality is set according to the energy, the traffic distribution and the deployment of nodes. Using this network mapping, our solution CoMN2 ensures the continuous network activity by efficiently swapping nodes from low critical area to highly critical area when required. Simulation results prove the effectiveness of our approach and show that the obtained improve-ment in terms of lifetime is in the order of 40%

Reliability for Emergency Applications in Internet of Things

International audienceThis paper addresses the Internet of Things (IoT) paradigm, which is gaining substantial ground in modern wireless telecommunications. The IoT describes a vision where heterogeneous objects like computers, sensors, Radio-Frequency IDentification (RFID)tags or mobile phones are able to communicate and cooperate efficiently to achieve common goals thanks to a common IP addressing scheme. This paper focuses on the reliability of emergency applications under IoT technology. These applications' success is contingent upon the delivery of high-priority events from many scattered objects to one or more objects without packet loss. Thus, the network has to be selfadaptiveand resilient to errors by providing efficient mechanisms for information distribution especially in the multi-hop scenario. As future perspective, we propose a lightweight and energy efficientjoint mechanism, called AJIA (Adaptive Joint protocol based on Implicit ACK), for packet loss recovery and route quality evaluation in theIoT. In this protocol, we use the overhearing feature, characterizing the wireless channels, as an implicit ACK mechanism. In addition, the protocol allows for an adaptive selection of the routing path based on the link quality

Oil-Abundance and Macroeconomic Performance in the GCC Countries

Natural resource abundance and its reliance in terms of exports and national income of any resource-rich country may have positive or negative effect on the macroeconomic performance. This paper tests this issue in case of GCC countries by assuming the two proxies for oil dependency as income-dependence and exports-dependence and by using a period 1980-2016. For that purpose, we utilize the non-linear ARDL of Shin et al. (2014) to verify the possible asymmetrical effects of increasing and decreasing oil-dependency on economic growth. We find that the increasing income-dependence has pleasant effect and decreasing income-dependence has adverse effect on economic growth of most of GCC countries. Further, the increasing exports-dependence has adverse effect and decreasing oil-exports dependence has pleasant effect on economic growth of most of GCC countries. Furthermore, asymmetrical effects of increasing and decreasing oil-dependence on economic growth have been found in most of country cases.  Keywords: Oil Dependency; Economic Growth, GCC Countries; non-linear ARDL JEL Classifications: Q26; O47; O57; C5

Egyptian Intra Agriculture Trade with COMESA Trading Partners: A Gravity Model

The regional trade provides better environment for any country to achieve the trade objective instead of a total free trade in this modern age. This study investigates the determinants of Egyptian agriculture trade with her 20 COMESA trading partners by using data of 1990-2015 and by applying Pooled Mean Group Estimators (PMG) on gravity model. Our results are confirming the panel cointegration in our model. Egyptian GDP and population are negatively influencing to the agriculture balance of trade. COMESA trading partners' GDP and population have positive impact on the balance of trade. The exchange rate depreciation has unfavorable impact on agriculture balance of trade in the short run and has a favorable impact in long run. This is an evidence for presence of J-curve hypothesis in Egyptian trade in COMESA region and also showing an elastic behavior of exchange rate on balance of trade in the long run. Hence, this study recommends to Egyptian policy makers to adopt depreciation policy to correct agriculture balance of trade with COMESA trading partners.           Keywords: Agriculture Balance of Trade, COMESA, GDP, Panel Cointegration JEL Classifications: E01, C33, F14, F5