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8th IEEE International Symposium on Cluster Computing and the Grid

作者： Bouteiller, Aurelien Desprez, Frederic UCBL INRIA CNRS ENS Lyon LIP ENS LyonUMR 5668 F-69364 Lyon 07 France

ISBN: (纸本)9781424442379

The GridRPC model is well suited for high performance computing on grids thanks to efficiently solving most of the issues raised by geographically and administratively split resources. Because of large scale, long range networks and heterogeneity, Grids are extremely prone to failures. GridRPC middleware are usually managing failures by using 1) TCP or other link network layer provided failure detector, 2) automatic checkpoints of sequential jobs and 3) a centralized stable agent to perform scheduling. Most recent developments have provided some new mechanisms like the optimal Chandra & Toueg & Aguillera failure detector, most numerical libraries now providing their own optimized checkpoint routine and distributed scheduling GridRPC architectures. In this paper we aim at adapting to these novelties by providing the first implementation and evaluation in a grid system of the optimal fault detector, a novel and simple checkpoint API allowing to manage both service provided checkpoint and automatic checkpoint (even for parallel services) and a scheduling hierarchy recovery algorithm tolerating several simultaneous failures. All those mechanisms are implemented and evaluated on a real grid in the DIET middleware.

关键词： GridRPC Fault tolerant Failure detector Checkpoint distributed algorithm

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Relative fairness and optimized throughput for Mobile Ad hoc Networks

Relative fairness and optimized throughput for Mobile Ad hoc...

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IEEE International Conference on Communications (ICC 2008)

作者： Benslimane, Abderrahirn Rachedi, Abderrezak Diwakar, Deepak Univ Avignon LIA CERI F-84911 Avignon France

ISBN: (纸本)9781424420742

Although IEEE 802.11 provides several transmission rates, a suitable rate adaptation taking into account the relative fairness among all competitive stations, according to the underlying channel quality remains a challenge in Mobile Ad hoc Networks (MANETs). The absence of any fixed infrastructure and any centralized control makes the existing solutions for WLANs like CARA (collision-aware rate adaptation) [4] not appropriate for MANETs. In this paper, we propose a new analytical model with a suitable approach to ensure a relative fairness among all competitive nodes of a particular channel. Our model deals with the channel quality while respecting the nodes, based on transmission successes and failures in a mobility context. Finally, each node calculates its own probability to access the channel in a distributed manner. We evaluate the performance of our scheme with others in the context of MANET via extensive and detailed simulations. The performance differentials are analysed using varying network load and transmission range. The simulation results illustrate that our proposed approach ensures a better tradeoff between fairness and throughput.

关键词： IEEE 802.11 MAC multihop ad hoc network distributed algorithm relative fairness

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Communication complexity evaluation for longest-lived directional multicasting in WANETs

Communication complexity evaluation for longest-lived direct...

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IEEE International Conference on Communications (ICC 2008)

作者： Liu, Xiaofei Guo, Song El Saddik, Abdulmotaleb Univ Ottawa Dept Comp Sci Ottawa ON Canada Univ Aizu Sch Engn & Comp Sci Aizu Wakamatsu Fukushima Japan

ISBN: (纸本)9781424420742

We consider the problem of maximizing the multicast lifetime in wireless ad hoc networks with directional antennas. By a simulation study, we have discovered that the existing distributed algorithm for such optimization problem may generate considerable number of control messages to build up a longest-lived multicast tree in large-scale networks. This may prohibit them from being used directly in ad hoc networks with limited energy and bandwidth. In this paper, we would like to investigate some mechanisms to improve the communication complexity of the distributed algorithm. We explore some important properties of this optimization problem from a graph theory perspective and derive several localized operations that are especially beneficial to the resource-constrained (e.g. limited energy, memory, and computation capabilities) wireless ad hoc networks. The localized operations have low complexity for both memory and computation requirements at each node. Our simulation results show that the proposed localized operations would allow our distributed algorithms to achieve an expected linear communication complexity.

关键词： wireless ad hoc network mullicast algorithm energy efficiency distributed algorithm

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The Stackelberg Power Control Game in Wireless Data Networks

The Stackelberg Power Control Game in Wireless Data Networks

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IEEE International Conference on Service Operations and Logistics and Informatics

作者： Jiang, Hua Ruan, Junhu Hebei Univ Engn Sch Econ & Management Handan Peoples R China

ISBN: (纸本)9781424420124

The Stackelberg game is introduced into the power control game, which makes all users in system work in the best equal Signal-to-interference(SIR). A new distributed algorithm based on Stackelberg Power control Game (SPG) is proposed. The simulation results indicate the algorithm can improve the capability of the system. Users receive higher utility and lower transmit power relatively, the use of wireless resources become more rational and impartial, and the convergence of the algorithm is good.

关键词： stackelberg game distributed algorithm wireless data networks power control

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New Approximation for Minimum-Weight Routing Backbone in Wireless Sensor Network

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3rd International Conference on Wireless algorithms, Systems and Applications

作者： Zhang, Ning Shin, Incheol Li, Bo Boyaci, Cem Tiwari, Ravi Thai, My T. Univ Florida Dept Comp & Informat Sci & Engn Gainesville FL 32611 USA

ISBN: (纸本)9783540885818

Our problem formulation is as follows. Given a weighted disk graph G where the weight of edge represents the transimission energy consumption, we wish to determine a dominating tree T of G such that the total weight of edges in T is minimized. To the best of our knowledge, this problem have, riot been addressed in the literature. Solving the dominating tree problem can yield a routing backbone for broadcast protocols since: (1) each node does not have to construct, their own broadcast tree, (2) utilize the virtual backbone to reduce the message overhead, and (3) the weight of backbone is minimized. Our contributions to this problem is multi-fold: First, the paper is the first to study this problem, prove the hardness of this problem and propose air approximation framework. Second, we present a heuristic to approximate the solution with low time complexity. Third, a distributed algorithm is provided for practical implementation. Finally, we verify the effectiveness of our proposal through simulation.

关键词： Dominating Tree Approximation algorithm General Graph distributed algorithm Time Complexity Wireless Sensor Network

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Self-Stabilizing Leader Election in Optimal Space

Self-Stabilizing Leader Election in Optimal Space

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10th International Symposium on Stabilization, Safety and Security of distributed Systems (SSS 2008)

作者： Datta, Ajoy K. Larmore, Lawrence L. Vemula, Priyanka Univ Nevada Sch Comp Sci Las Vegas NV 89154 USA

A. silent self-stabilizing asynchronous distributed algorithm, SSLE, for the leader election problem, in a connected unoriented network with unique IDs, is given. SSLE uses O(log n) space per process and stabilizes in... 详细信息

ISBN: (纸本)9783540893349

关键词： distributed algorithm leader election self-stabilization

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Computing and Updating the Process Number in Trees

Computing and Updating the Process Number in Trees

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12th International Conference on Principles of distributed Systems

作者： Coudert, David Huc, Florian Mazauric, Dorian Univ Nice Sophia Antipolis INRIA CNRS I3S Nice France

ISBN: (纸本)9783540922209

The process number is the minimum number of requests that have to be simultaneously disturbed during a routing reconfiguration phase of a connection oriented network. From a graph theory point of view, it is similar to the node search number, and thus to the path-width, however they are not always equal. In general determining these parameters is NP-complete. We present a distributed algorithm to compute these parameters and the edge search number, in trees. It can be executed in an asynchronous environment, requires n steps, an overall computation time of O(n log n), and n messages of size log(3) n + 2. Then, we propose a distributed algorithm to update these parameters on each component of a forest after addition or deletion of any tree edge. This second algorithm requires O(D) steps, an overall computation time of O(D log n), and O(D) messages of size log(3) n + 3, where D is the diameter of the new connected component.

关键词： Pathwidth process number distributed algorithm

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Game-Theoretic Analysis of Topology Control

Game-Theoretic Analysis of Topology Control

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作者： Komali, Ramakant S. Virginia Polytechnic Institute and State University

学位级别：Ph.D.

Ad hoc networks are emerging as a cost-effective, yet, powerful tool for communication. These systems, where networks can emerge and converge on-the-fly, are guided by the forward-looking goals of providing ubiquitous connectivity and constant access to information. Due to power and bandwidth constraints, the vulnerability of the wireless medium, and the multi-hop nature of ad hoc networks, these networks are becoming increasingly complex dynamic systems. Besides, modern radios are empowered to be reconfigurable, which harbors the temptation to exploit the system. To understand the implications of these issues, some of which pose significant challenges to efficient network design, we study topology control using game theory. We develop a game-theoretic framework of topology control that broadly captures the radio parameters, one or more of which can be tuned under the purview of topology control. In this dissertation, we consider two parameters, viz. transmit power and channel, and study the impact of controlling these on the emergent topologies. We first examine the impact of node selfishness on the network connectivity and energy efficiency under two levels of selfishness: (a) nodes cooperate and forward packets for one another, but selfishly minimize transmit power levels and; (b) nodes selectively forward packets and selfishly control transmit powers. In the former case, we characterize all the Nash Equilibria of the game and evaluate the energy efficiency of the induced topologies. We develop a better-response-based dynamic that guarantees convergence to the minimal maximum power topology. We extend our analysis to dynamic networks where nodes have limited knowledge about network connectivity, and examine the tradeoff between network performance and the cost of obtaining knowledge. Due to the high cost of maintaining knowledge in networks that are dynamic, mobility actually helps in information-constrained networks. In the latter case, nodes selfishly adapt the

关键词： ad hoc network topology control game theory network design cross-layer optimization distributed algorithm node cooperation cognitive network

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Tree Decontamination with Temporary Immunity

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19th Annual International Symposium on algorithms and Computation (ISAAC)

作者： Flocchini, Paola Mans, Bernard Santoro, Nicola Univ Ottawa Ottawa ON Canada Macquarie Univ Sydney NSW 2109 Australia Carleton Univ Ottawa ON K1S 5B6 Canada

ISBN: (纸本)9783540921813

Consider a tree network that has been contaminated by a persistent and active virus: when infected, a network site will continuously attempt to spread the virus to all its neighbours. The decontamination problem is that of disinfecting the entire network using a team of mobile antiviral system agents, called cleaners, avoiding any recontamination of decontaminated areas. A cleaner is able to decontaminate any infected node it visits;once the cleaner departs, the decontaminated node is immune for t >= 0 time units to viral attacks from infected neighbours. After the immunity time t is elapsed, re-contamination can occur. The primary research objective is to determine the minimum team size, as well as the solution strategy, that is the protocol that would enable such a minimal team of cleaners to perform the task. The network decontamination problem has been extensively investigated in the literature, and a very large number of studies exist on the subject. However, all the existing work is limited to the special case t = 0. In this paper we examine the tree decontamination problem for any value t >= 0. We determine the minimum team size necessary to disinfect any given tree with immunity time t. Further we show how to compute for all nodes of the tree the minimum team size and implicitly the solution strategy starting from each starting node;these computations use a total of Theta(n) time (serially) or Theta(n) messages (distributively). We then provide a complete structural characterization of the class of trees that can be decontaminated with k agents and immunity time t;we do so by identifying the forbidden subgraphs and analyzing their properties. Finally, we consider generic decontamination algorithms, i.e. protocols that work unchanged in a large class of trees, with little knowledge of their topological structure. We prove that, for each immunity time t >= 0, all trees of height at most It can be decontaminated by a team of k = [2h/t+2] agents whose only knowl

关键词： Network decontamination tree networks mobile agents antiviral agents distributed algorithm

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A simple randomized scheme for constructing low-weight k-connected spanning subgraphs with applications to distributed algorithms

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THEORETICAL COMPUTER SCIENCE 2007年第1-3期385卷 101-114页

作者： Khan, Maleq Pandurangan, Gopal Kumar, V. S. Anil Purdue Univ Dept Comp Sci W Lafayette IN 47907 USA Virginia Polytech Inst & State Univ Dept Comp Sci Blacksburg VA 24061 USA

The main focus of this paper is the analysis of a simple randomized scheme for constructing low-weight k-connected spanning subgraphs. In this paper, we focus on the metric graph. We use the term metric graph for a complete graph with metric weights. We first show that our scheme gives a simple approximation algorithm to construct a minimum-weight k-connected spanning subgraph in a metric graph, an NP-hard problem. We show that our algorithm gives an approximation ratio of O(k log n) for a metric graph, O(k) for a random graph with nodes uniformly randomly distributed in [0, 1](2) and O(log n/k) for a complete graph k with random edge weights U(0, 1). We show that our scheme is optimal with respect to the amount of "local information" needed to compute any connected spanning subgraph. We then show that our scheme can be applied to design an efficient distributed algorithm for constructing such an approximate k-connected spanning subgraph (for any k >= 1) in a point-to-point distributed model, where the processors form a complete network. Our algorithm takes O(log n/k) time and an expected number of O(nk log n/k) messages. Our result in conjunction with a result of Korach et al. [E. Korach, S. Moran, S. Zaks, The optimality of distributive constructions of minimum weight and degree restricted spanning trees in a complete network of processors, SIAM Journal on Computing 16 (2) (1987) 231-236] implies that the expected message complexity of our algorithm is significantly better than the best distributed algorithm that finds an optimal k-connected subgraph. We also show that for geometric instances, our randomized scheme constructs low-degree k-connected spanning subgraphs which have O(k log n) maximum degree, with high probability. (c) 2007 Elsevier B.V. All rights reserved.

关键词： k-connected spanning subgraph minimum spanning tree randomized approximation algorithm distributed algorithm probabilistic analysis

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