A New Approach to Manage QoS in Distributed Multimedia Systems

Dealing with network congestion is a criterion used to enhance quality of service (QoS) in distributed multimedia systems. The existing solutions for the problem of network congestion ignore scalability considerations because they maintain a separate classification for each video stream. In this paper, we propose a new method allowing to control QoS provided to clients according to the network congestion, by discarding some frames when needed. The technique proposed, called (m,k)-frame, is scalable with little degradation in application performances. (m,k)-frame method is issued from the notion of (m,k)-firm realtime constraints which means that among k invocations of a task, m invocations must meet their deadline. Our simulation studies show the usefulness of (m,k)-frame method to adapt the QoS to the real conditions in a multimedia application, according to the current system load. Notably, the system must adjust the QoS provided to active clients1 when their number varies, i.e. dynamic arrival of clients.Comment: 10 pages, International Journal of Computer Science and Information Security (IJCSIS

To have an Idea on NoSQL Databases

NoSQL databases (initially non-SQL, then Not Only SQL) are specifically designed to handle large amounts of data. They have been developed since the 1970s, but they have gained the interest of academia and industry for about two decades. This is because of their powerful characteristics and lack of relational databases, which are the most widely used data sources around the world. Indeed, these databases are based on the relational model, which is materialized by a relational database management system (RDBMS). Although RDBMS efficiently manage data (tables), they have many drawbacks that make them unsuitable for managing current data, which come mainly from Internet applications. They are called Big Data and they are used for example by Twitter, FaceBook, LinkedIn, .... They are very numerous and tend to change quickly. In fact, among the disadvantages of relational databases, we can mention: non-flexibility, non-scalability, ... On the contrary, NoSQL databases evolve very well (scaling) and almost all NoSQL databases are schema-free (we can add or delete an entity or a relationship at any time during execution). In this article, we begin by giving an overview of relational databases and their characteristics. We then describe the NoSQL databases and their main characteristics, knowing that there are as many different characteristics as  "NoSQL databases" products. We then give the taxonomy of NoSQL databases, which distinguishes four main types of NoSQL databases: key-value, wide-column, document and graphical databases. We will then give some elements of each type of database through the use of a product, an implementation of a kind of such a database

Optimal RoadSide Units Distribution Approach in Vehicular Ad hoc Network

A vehicular ad hoc network is a particular type of ad hoc mobile network. It is characterized by high mobility and frequent disconnection between vehicles. For this, the roadside units (RSUs) deployment permits to enhance the network connectivity. The objective of this work is to provide an optimized RSUs placement for enhancing the network connectivity and maximizing the accident coverage with reducing the deployment cost. In this paper, we propose our approach called Optimized RoadSide units Deployment (ORSD). The proposed approach comprises a two-step, in the first step, ORSD finds the RSUs candidate locations based on network density and connectivity. We calculated the connectivity of each segment based on speed and arrival information’s.  The second step permit to find the optimal solution of our proposed objective function. The objective function permits to enhance the network connectivity and maximizing the accident coverage.  To find the optimal solution of our objective function is an NP-complete problem of order o(n²) .  Therefore, we propose to solve this problem in two phases, so that it becomes a simple linear problem to solve. The ORSD is proposed for urban and high way scenarios. The extensive simulation study is conducted in order to assess the effectiveness of the proposed approach. We use the Simulator of Urban MObility (SUMO) for generating different traffic scenarios. We develop scripts to extract different information as density, speed and travel time in each segment. Then, we develop an algorithm to calculate connectivity probability for each segment. Then, we implement our objective function to finds optimal RSUs positions in terms of connectivity, accident cover and cost

An Unequal Cluster-based Routing Protocol Based on Data Controlling for Wireless Sensor Network

Wireless Sensor Networks (WSN) differ from traditional wireless communication networks in several characteristics. One of these characteristics is power awarness, due to the fact that the batteries of sensor nodes have a restricted lifetime and are difficult to be replaced. Therefore, all protocols must be designed to minimize energy consumption and preserve the longevity of the network. In this paper, we propose (i) to fairly balance the load among nodes. For this, we generate an unequal clusters size where the cluster heads (CH) election is based on energy availability, (ii) to reduce the energy consumption due to the transmission by using multiple metrics in the CH jointure process and taking into account the link cost, residual energy and number of cluster members to construct the routing tree and (iii) to minimize the number of transmissions by avoiding the unnecessary updates using sensitive data controller. Simulation results show that our Advanced Energy-Efficient Unequal Clustering (AEEUC) mechanism improves the fairness energy consumption among all sensor nodes and achieves an obvious improvement on the network lifetime

Des systèmes d'aide à la décision temps réel et distribués : modélisation par agents

Decision Support Systems (DSS) should help users to take the best decisions as earlier as possible. In this thesis, we are interested in such DSS which are based on the multiagent paradigm. Indeed, multiagent systems are often the best way used to build computer systems that need multicriteria queries because they permit to design complex computerized systems. Moreover, in DSS, temporal constraints are very strong and in a lot of cases partial or incomplete results obtained early are preferred and more useful than complete and accurate results obtained too late. Anytime techniques seem to be a good solution in order to deal with these situations, that is to take into account real-time aspects in this framework. In this document, we present a method and a model to design a real-time multiagent system is based on anytime techniques. Furthermore, we have taken into account the inherent distributed aspect of current DSS in our model.Les systèmes d'aide à la décision (SAD) doivent permettre aux utilisateurs (décideurs) de prendre les meilleures décisions dans les meilleurs délais. Dans cette thèse, nous nous sommes intéressés aux systèmes qui reposent sur une architecture multi-agents. En effet, les systèmes multi-agents (SMA) permettent de construire des systèmes informatiques ayant recours à l'interrogation multi-critères, souvent utilisée dans les SAD. De façon plus générale, les SMA permettent de concevoir des systèmes qui sont de nature complexe. Cependant, ils n'intègrent pas la notion de contraintes temporelles qui sont souvent très fortes dans les SAD. De plus, dans ces systèmes, des résultats même partiels ou incomplets obtenus dans les temps sont souvent préférés car plus utiles pour la prise de décision que des résultats complets et précis obtenus en retard. Pour cela, les techniques ``anytime'' (raisonnement progressif) semblent une excellente solution. Dans cette thèse, nous présentons une méthode de conception d'un système multi-agent temps réel basé sur l'exploitation des techniques ``anytime''. De plus, nous prenons en compte dans notre modèle l'aspect souvent distribué des SAD

Des systèmes multi-agents Anytime pour la conception de systèmes d'aide à la décision

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Des systèmes d'aide à la décision temps réel et distribués (modélisation par agents)

Dans cette thèse, nous nous sommes intéressés aux systèmes qui reposent sur une architecture multi-agents et présentons une méthode de conception d'un système multi-agent temps réel basé sur l'exploitation des techniques " anytime " (raisonnement progressif). De plus, nous prenons en compte dans notre modèle l'aspect souvent distribué des systèmes d'aide à la décision.In this thesis, we are interessed in such decision support system which are based on the multiagent paradigm and we present a method and a model to design a real-time aspect multiagent system based on anytime techniques. Furthermore, we have taken into account the inherent distributed aspect of current decision support system in our model.LE HAVRE-BU Centrale (763512101) / SudocSudocFranceF

Are Corridors a Key Asset for the Deployment of Short Food Supply Chains?

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