Concepts and evolution of research in the field of wireless sensor networks

The field of Wireless Sensor Networks (WSNs) is experiencing a resurgence of interest and a continuous evolution in the scientific and industrial community. The use of this particular type of ad hoc network is becoming increasingly important in many contexts, regardless of geographical position and so, according to a set of possible application. WSNs offer interesting low cost and easily deployable solutions to perform a remote real time monitoring, target tracking and recognition of physical phenomenon. The uses of these sensors organized into a network continue to reveal a set of research questions according to particularities target applications. Despite difficulties introduced by sensor resources constraints, research contributions in this field are growing day by day. In this paper, we present a comprehensive review of most recent literature of WSNs and outline open research issues in this field

MMEDD: Multithreading Model for an Efficient Data Delivery in wireless sensor networks

Nowadays, the use of Wireless Sensor Networks (WSNs) is increasingly growing as they allow a large number of applications. In a large scale sensor network, communication among sensors is achieved by using a multihop communication. However, since the sensor is limited by its resources, sensors' operating systems are developed in order to optimize the management of these resources, especially the power consumption. Therefore, the hybrid operating system Contiki uses a low consumption layer called Rime which allows sensors to perform multihop sending with a low energy cost. This is favored by the implementation of lightweight processes called protothreads. These processes have a good efficiency/consumption ratio for monolithic tasks, but the management of several tasks remains a problem. In order to enable multitasking, Contiki provides to users a preemptive multithreading module that allows the management of multiple threads. However, it usually causes greater energy wastage. To improve multithreading in sensor networks, a Multithreading Model for an Efficient Data Delivery (MMEDD) using protothreads is proposed in this paper. Intensive experiments have been conducted on COOJA simulator that is integrated in Contiki. The results show that  MMEDD provides better ratio message reception rate/energy consumption than other architectures

Ordonnancement des sauvegardes/reprises d'applications de calcul haute performance dans les environnements dynamiques

The technological advances has led major organizations such as enterprises, universities andresearch institutes to acquire intranets consisting of several servers and many workstations.However, in some of these organizations, the resources are rarely used at nights, weekends and onholidays, thus releasing a large computing power available and unused.This thesis discusses the exploitation of the idle period of workstaions in order to run HPCapplications. The workstations retained are restarted and integrated in dynamically formed clusters.However, the idle periods do not always permit the complete carrying out of the computationsallocated to them. The checkpointing mechanisms are then used to save in a certain period, theexecution context of applications for a possible restart. It is worth nothing that checkpointing all theprocesses in the required period is not always possible. We propose a scheduling model ofcheckpointing in parallel, which takes into account the time constraints imposed and the bandwidthconstraints (network and disk) to maximize the computation time already taken for the applicationswhich are to be checkpointed.Les avancées technologiques ont conduit les grandes organisations telles que les entreprises,les universités et les instituts de recherche à se doter d'intranets constitués de plusieurs serveurs etd'un grand nombre de postes de travail. Cependant dans certaines de ces organisations, les postes detravail sont très peu utilisés pendant la nuit, les week-ends et les périodes de congés, libérant ainsiune grande puissance de calcul disponible et inutilisée.Dans cette thèse, nous étudions l'exploitation de ces temps de jachère afin d'exécuter desapplications de calcul haute performance. A cet effet, nous supposons que les postes acquis sontrebootés et intégrés à des grappes virtuelles constituées dynamiquement. Toutefois, ces temps dejachère ne permettent pas toujours d'exécuter les applications jusqu'à leur terme. Les mécanismes desauvegarde/reprise (checkpointing) sont alors utilisés pour sauvegarder, dans un certain délai, lecontexte d'exécution des applications en vue d'une éventuelle reprise. Il convient de noter que lasauvegarde de tous les processus dans les délais impartis n'est pas toujours possible. Nousproposons un modèle d'ordonnancement des sauvegardes en parallèle, qui tient compte descontraintes temporelles imposées et des contraintes liées aux bandes passantes (réseau et disque),pour maximiser les temps de calcul déjà effectués pour les applications candidates à la sauvegarde

Scheduling checkpoint/restart of high performance computing on dynamic environments

Les avancées technologiques ont conduit les grandes organisations telles que les entreprises,les universités et les instituts de recherche à se doter d'intranets constitués de plusieurs serveurs etd'un grand nombre de postes de travail. Cependant dans certaines de ces organisations, les postes detravail sont très peu utilisés pendant la nuit, les week-ends et les périodes de congés, libérant ainsiune grande puissance de calcul disponible et inutilisée.Dans cette thèse, nous étudions l'exploitation de ces temps de jachère afin d'exécuter desapplications de calcul haute performance. A cet effet, nous supposons que les postes acquis sontrebootés et intégrés à des grappes virtuelles constituées dynamiquement. Toutefois, ces temps dejachère ne permettent pas toujours d'exécuter les applications jusqu'à leur terme. Les mécanismes desauvegarde/reprise (checkpointing) sont alors utilisés pour sauvegarder, dans un certain délai, lecontexte d'exécution des applications en vue d'une éventuelle reprise. Il convient de noter que lasauvegarde de tous les processus dans les délais impartis n'est pas toujours possible. Nousproposons un modèle d'ordonnancement des sauvegardes en parallèle, qui tient compte descontraintes temporelles imposées et des contraintes liées aux bandes passantes (réseau et disque),pour maximiser les temps de calcul déjà effectués pour les applications candidates à la sauvegarde.The technological advances has led major organizations such as enterprises, universities andresearch institutes to acquire intranets consisting of several servers and many workstations.However, in some of these organizations, the resources are rarely used at nights, weekends and onholidays, thus releasing a large computing power available and unused.This thesis discusses the exploitation of the idle period of workstaions in order to run HPCapplications. The workstations retained are restarted and integrated in dynamically formed clusters.However, the idle periods do not always permit the complete carrying out of the computationsallocated to them. The checkpointing mechanisms are then used to save in a certain period, theexecution context of applications for a possible restart. It is worth nothing that checkpointing all theprocesses in the required period is not always possible. We propose a scheduling model ofcheckpointing in parallel, which takes into account the time constraints imposed and the bandwidthconstraints (network and disk) to maximize the computation time already taken for the applicationswhich are to be checkpointed

Virtual Machines Performance in HPC Environments

International audienc

Energy efficient clustering algorithm for Wireless Sensor Networks using the ABC metaheuristic

International audienc

Optimized Clustering Algorithms for Large Wireless Sensor Networks: A Review

During the past few years, Wireless Sensor Networks (WSNs) have become widely used due to their large amount of applications. The use of WSNs is an imperative necessity for future revolutionary areas like ecological fields or smart cities in which more than hundreds or thousands of sensor nodes are deployed. In those large scale WSNs, hierarchical approaches improve the performance of the network and increase its lifetime. Hierarchy inside a WSN consists in cutting the whole network into sub-networks called clusters which are led by Cluster Heads. In spite of the advantages of the clustering on large WSNs, it remains a non-deterministic polynomial hard problem which is not solved efficiently by traditional clustering. The recent researches conducted on Machine Learning, Computational Intelligence, and WSNs bring out the optimized clustering algorithms for WSNs. These kinds of clustering are based on environmental behaviors and outperform the traditional clustering algorithms. However, due to the diversity of WSN applications, the choice of an appropriate paradigm for a clustering solution remains a problem. In this paper, we conduct a wide review of proposed optimized clustering solutions nowadays. In order to evaluate them, we consider 10 parameters. Based on these parameters, we propose a comparison of these optimized clustering approaches. From the analysis, we observe that centralized clustering solutions based on the Swarm Intelligence paradigm are more adapted for applications with low energy consumption, high data delivery rate, or high scalability than algorithms based on the other presented paradigms. Moreover, when an application does not need a large amount of nodes within a field, the Fuzzy Logic based solution are suitable

Clustering algorithm for wireless sensor networks : the honeybee swarms nest-sites selection process based approach

International audienc

Integrating Deadline-Constrained Checkpointing in a Batch Scheduler for Dynamic Environments

International audienceThis paper sets out to present the integration of the scheduling of deadline-constrained checkpointing in a batch scheduler for dynamic environments such as virtual clusters. The checkpointing scheduler implemented focuses on the parallel checkpointing on a unique server of long-running independent applications in a virtual cluster made up of free resources for long periods of an intranet network, assuming that the resources must be released within a delay T . As parallel checkpointing on a unique server can face bandwidth constraints, the checkpointing scheduler uses a func tion that gives the aggregated bandwidth suitable for the parallel checkpointing of m applications of aggregated size V to solve the deadline-constrained checkpointing problem within the deadline T. Specifically, we present the integration of the checkpointing scheduler in the batch scheduler OAR. This implementation uses data from the OAR database for the checkpointing scheduling. It is portable and can be easily modified to interact with any other batch scheduler, provided that the structure of the database is known and an estimator of the bandwidth of the system suitable for parallel checkpointing available. Experimental results obtained on a virtual cluster built on GRID5000 show that the implementation of the checkpointing scheduler does not induce a significant overhead on checkpointing mechanisms. As a consequence, this work aims at providing HPC platforms for a tool to enhance the quality of services offered to end users

MMEDD: Multithreading Model for an Efficient Data Delivery in wireless sensor networks

International audienc