Vehicular Ad-hoc Networks: Architecture, Applications and Challenges

With the emergence of Information and Communication Technologies (ICT) and wireless embedded sensing devices into modern vehicles, Intelligent Transport System (ITS) becomes a reality and an indispensable component of smart cities. The purpose of ITS is to improve road safety and traffic efficiency as well as offering infotainments services. In fact, warning drivers in the right time about dangerous situations on the road and providing them with prior information about traffic will undoubtedly leads to enhance driver's safety and reduce traffic congestion. Technically speaking, ITS is based on self-organizing wireless networks, known as vehicular ad-hoc networks (VANETs). Mobile vehicles in VANET might play the role of stationary sensors in infrastructure-based networks. They can detect, gather and disseminate real-time data about traffic, driving conditions and potential hazards on roads. In this respect, we review in this study, recent developments on the design of VANET protocols and applications. We first introduce the architecture of VANETs then we review their unique characteristics and applications. Thereafter, we discuss the main research challenges and open issues to be considered for designing efficient and a cost-effective VANET protocols and applications

CDP: a Content Discovery Protocol for Mobile P2P Systems

The emergence of affordable wireless and mobile devices was a key step towards deploying mobile peer-to-peer (P2P) systems. The latter allow users to share and search diverse multimedia resources over Mobile Ad-hoc Networks (MANETs). Due to the nature of MANETs, P2P mobile systems brought up many new thriving challenges, in particular with regard to the content discovery issue. Thus, the design of an efficient content discovery protocol has been of paramount importance. The thriving challenge is to (i) locate relevant peers sharing pertinent resources for users queries and then (ii) to ensure that those peers would be reached by considering different MANET constraints (e.g., peer mobility, battery energy, peer load, to cite a few). Even though the literature witnesses a wealthy number of content discovery protocols, only few of them have considered the above-mentioned requirements. To overcome this shortage, we introduce in this paper an efficient Content Discovery Protocol (CDP) for P2P mobile systems. The idea underlying our proposal is to route users queries to relevant peers that are (1) more suitable to answer the user query according to its content, (2) more stable to relay query hits, (3) less loaded to avoid the network congestion issue and (4) having more battery lifetime to avoid the network partitioning issue. The performed experiments show that CDP outperforms its competitor in terms of effectiveness and efficiency

Routing Approach for P2P Systems Over MANET Network

Thanks to the great progress in mobile and wireless technologies, Internet-distributed applications like P2P file sharing are nowadays deployed over MANET (i.e., P2P mobile systems). These applications allow users to search and share diverse multimedia resources over MANET. Due the nature of MANET, P2P mobile systems brought up many new thriving challenges regarding the query routing issue. To tackle this problem, we introduce a novel context-aware query routing protocol for unstructured P2P mobile file sharing systems. Our protocol (i) locates relevant peers sharing pertinent resources for user's query and (ii) ensures that those peers would be reached by considering different MANET constraints (e.g., query content, peer mobility, battery energy, peer load). In order to consider all these constraints for choosing the relevant peers, we are based on the technique for order preferences by similarity to ideal solution (TOPSIS). We implemented the proposed protocol and compared its routing efficiency and retrieval effectiveness with another protocol taken from the literature. Experimental results show that our scheme carries out better than the baseline protocol with respect to accurac

Etude de la Distribution de Calculs Creux sur une Grappe Multi-coeurs

Nowadays, high performance computing is becoming more and more important in different fields research and industry, such as medical imaging and diagnostics, mathematics as well as oil exploration. It refers to intensive computing in some applications where one needs to use a large number of computing resources (computing power, memory rate, storage space, etc.). Thus, it is necessary in this case to run these applications on architectures parallel making multiple computers work together and running over 10 operations at floating point per second (or a petaflops). 15 Parallel computation consists of executing one or more programs, simultaneously, by multiple processors. In general, we have two ways to perform a parallel calculation. The first is to cut the program into several calculation tasks then, run all these parallel spots by different processors. The second requires partitioning the data, so that each part of the data is assigned to a different processor. Then, all the processors run the instructions of the same program in parallel but by operating on different data . This last method, called parallelism of data, is that retained in this memory. Digital analysis is one of the areas where the use of platforms is essential parallel, in particular, in the case where numerical methods treat hollow matrices. This last method, called parallelism of data, is that retained in this memory. Digital analysis is one of the areas where the use of platforms is essential parallel, in particular, in the case where numerical methods treat hollow matrices. A hollow matrix is a very large matrix that contains a small proportion non-zero elements. These matrices can come from different domains such as simulation structural mechanics, image / signal processing, the study of the dynamics of fluids etc.Comment: in French, Master's thesis, University Tunis El Manar (2016