Search results for "Distributed"

Implementing the erosion component of a physically based and distributed model (tRIBS). A first application to an experimental basin.

2008

CVS: Using VLANs to Counteract the Effect of Topology Changes in Quasi-Static Mesh Access Networks

2006

Mesh networks are candidate to play the role of switched Ethernet LANs over extended areas and with a sensibly higher flexibility. Actually, mesh networks can exploit both Ethernet and wireless technologies, e.g. Wi-Fi and/or free-space optical links, to provide a high degree of redundancy in an access network, and to provide users with powerful means to connect with each other. By using such technologies, the mesh topology remains stable for hours, so that the mesh topology can be considered quasi-static. However, large meshes require a heavy overhead in the network control plane as for the management of end-to-end paths, which can change due to mobility of users and due to occasional fail…

Gigabit Ethernet backbones with active loops

2001

The current standard Ethernet switches are based on the Spanning Tree (ST) protocol. Their most important restriction is that they can not work when the topology has active loops. In fact, the ST protocol selects a tree from the real topology by blocking the links that are not involved in the tree. This restriction produces a network traffic unbalancing behavior saturating those link near the root switch while rest of links will be idle or with a very low utilization. This paper proposes a new transparent switch protocol for Gigabit Ethernet backbones that considerably improves the performance of current ones. The proposed protocol is named ALOR for Active Loops and Optimal Routing. ALOR pr…

LSOM: A Link State protocol Over MAC addresses for metropolitan backbones using Optical Ethernet switches

2003

This paper presents a new protocol named "Link State Over MAC" (LSOM) for Optical Ethernet switches to allow the use of active loop topologies, like meshes, in Metropolitan Area Networks (MAN) or even Wide Area Networks (WAN) backbone. In this respect, LSOM is an alternative to a ring topology as proposed in draft IEEE 802.17 Resilient Packet Ring (RPR) or a tree topology using IEEE802. 1D Rapid Spanning Tree Protocol (RSTP). LSOM provides higher scalability and is able to achieve better bandwidth utilization and lower latency than RSTP and RPR. Simulation results for 4-node and 9-node topologies show that LSOM can improve throughput over RPR by a factor of up to 1.7. Furthermore, full free…

A study of mobility and reachability in ad hoc networks using stochastic activity networks

2006

The integration of ad-hoc networks into real environments is now becoming more and more common and supervision and control systems are no exception. The efficiency of the communication in these networks as well as various other factors, are governed by the working area, the number of nodes, mobility, transmission power, etc. In this paper, the mobility and reachability of mobile nodes appearing spontaneously in a large installation such as can be found in a water purification system are studied. These nodes form an ad-hoc network and communicate between each other in order to finally reach a fixed node which can offer them information from the rest of the system in real time or act as a gat…

Two Levels SPF-Based System to Interconnect Partially Decentralized P2P File Sharing Networks

2005

Partially decentralized P2P (PDP2P) networks are a subset of P2P networks. Roles of nodes are different according to their functionality in the network. Nowadays, there are many PDP2P networks, with different characteristics. It is necessary to find a way to join those autonomous networks. We have not found any interconnection system, so in this article we present a new hierarchical system for interconnecting peers from different PDP2P networks. It will allow sharing data, content and resources between networks. It can be employed between sensor networks, P2P networks, and generally, overlay networks. Oldest superpeers or brokers with higher bandwidth in the PDP2P network will belong to hig…

Backwards Martingales and Exchangeability

2020

With many data acquisitions, such as telephone surveys, the order in which the data come does not matter. Mathematically, we say that a family of random variables is exchangeable if the joint distribution does not change under finite permutations. De Finetti’s structural theorem says that an infinite family of E-valued exchangeable random variables can be described by a two-stage experiment. At the first stage, a probability distribution Ξ on E is drawn at random. At the second stage, independent and identically distributed random variables with distribution Ξ are implemented.

Scheduling on Two Types of Resources: a Survey

2020

International audience; We study the problem of executing an application represented by a precedence task graph on a parallel machine composed of standard computing cores and accelerators. Contrary to most existing approaches, we distinguish the allocation and the scheduling phases and we mainly focus on the allocation part of the problem: choose the most appropriate type of computing unit for each task. We address both off-line and on-line settings and design generic scheduling approaches. In the first case, we establish strong lower bounds on the worst-case performance of a known approach based on Linear Programming for solving the allocation problem. Then, we refine the scheduling phase …

Distributed and proximity-constrained C-means for discrete coverage control

2018

In this paper we present a novel distributed coverage control framework for a network of mobile agents, in charge of covering a finite set of points of interest (PoI), such as people in danger, geographically dispersed equipment or environmental landmarks. The proposed algorithm is inspired by C-Means, an unsupervised learning algorithm originally proposed for non-exclusive clustering and for identification of cluster centroids from a set of observations. To cope with the agents' limited sensing range and avoid infeasible coverage solutions, traditional C-Means needs to be enhanced with proximity constraints, ensuring that each agent takes into account only neighboring PoIs. The proposed co…

AnySeq: A High Performance Sequence Alignment Library based on Partial Evaluation

2020

Sequence alignments are fundamental to bioinformatics which has resulted in a variety of optimized implementations. Unfortunately, the vast majority of them are hand-tuned and specific to certain architectures and execution models. This not only makes them challenging to understand and extend, but also difficult to port to other platforms. We present AnySeq - a novel library for computing different types of pairwise alignments of DNA sequences. Our approach combines high performance with an intuitively understandable implementation, which is achieved through the concept of partial evaluation. Using the AnyDSL compiler framework, AnySeq enables the compilation of algorithmic variants that ar…