In this paper, we propose a new trajectory estimation method named TRADE (TRAjectory estimation in decentralized way). TRADE is a range-free localization algorithm in fully decentralized mobile ad hoc networks. In TRA...
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ISBN:
(纸本)9781605586168
In this paper, we propose a new trajectory estimation method named TRADE (TRAjectory estimation in decentralized way). TRADE is a range-free localization algorithm in fully decentralized mobile ad hoc networks. In TRADE, each mobile node periodically transmits messages containing its estimated trajectory information, and re-computes its own trajectory using those from its neighbors. This information exchange considerably contributes to improvement of the position accuracy. Furthermore, we give the optimal design of the protocol based on the analysis of the algorithm property. Through the analysis, we consider how much trajectory information should be exchanged among nodes to estimate the position within a certain error range in the protocol design. We have evaluated the position accuracy under various settings, and have shown the effectiveness of the protocol in the real world through two realistic application examples.
This paper presents a decentralized Multi-Agent System (DMAS) for dynamic resource allocation. The DMAS consists of two parts: (i) Agents movement system, and (ii) Agent management system. The agent movement system is...
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ISBN:
(纸本)9781424428526
This paper presents a decentralized Multi-Agent System (DMAS) for dynamic resource allocation. The DMAS consists of two parts: (i) Agents movement system, and (ii) Agent management system. The agent movement system is used to govern the movement of agents and manipulates the task scheduling and workload equalizing between machines. A hybrid Roam-Space movements in the DMAS are discussed. The agent management system is proposed to handle dynamic events and provide an environment for agents negotiation. In this paper, a new dynamic event, called Machine Degradation (MD) is given, and its behavior is introduced. Furthermore, simulation results for different types of the resource allocation problems are given to show the ability of the proposal approach.
In an adversarial environment, various kinds of attacks become possible if malicious nodes could claim fake locations that are different from their physical locations. In this paper, we propose a secure localization m...
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In an adversarial environment, various kinds of attacks become possible if malicious nodes could claim fake locations that are different from their physical locations. In this paper, we propose a secure localization mechanism that detects existence of these nodes, termed as phantom nodes, without relying on any trusted entities, ail approach significantly different from the existing ones. The proposed mechanism enjoys a set of nice features. First, it does not have my central point of attack. All nodes play the role of verifier, by generating local map, i.e. a view constructed based on ranging information from its neighbors. Second, this distributed and localized construction results in strong robustness against adversaries: even when the number of phantom nodes is greater than that of honest nodes, we can filter out most of the phantom nodes. Our analytical results as well as simulations under realistic noisy settings demonstrate that the proposed mechanism is effective in the presence of a large number of phantom nodes. (C) 2007 Elsevier B.V. All rights reserved.
As a basic requirement of live peer-to-peer multimedia streaming sessions, the streaming playback rate needs to be strictly enforced at each of the peers. In real-world peer-to-peer streaming sessions with very large ...
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ISBN:
(纸本)9780819469908
As a basic requirement of live peer-to-peer multimedia streaming sessions, the streaming playback rate needs to be strictly enforced at each of the peers. In real-world peer-to-peer streaming sessions with very large scales, the number of streaming servers for each session may not be easily increased, leading to a limited supply of bandwidth. To scale to a large number of peers, one prefers to regulate the bandwidth usage on each of the overlay links in an optimal fashion, such that limited supplies of bandwidth may be maximally utilized. In this paper, we propose a decentralized bandwidth allocation algorithm that can be practically implemented in peer-to-peer streaming sessions. Given a mesh P2P topology, our algorithm explicitly reorganizes the bandwidth of data transmission on each overlay link, such that the streaming bandwidth demand is always guaranteed to be met at any peer in the session, without depending on any a priori knowledge of available peer upload or overlay link bandwidth. Our algorithm is especially useful when there exists no or little surplus bandwidth supply from servers or other peers. It adapts well to time-varying availability of bandwidth, and guarantees bandwidth supply for the existing peers during volatile peer dynamics. We demonstrate the effectiveness of our algorithm with in-depth simulation studies.
In this paper, we consider the task allocation problem for computing a large set of equal-sized independent tasks on a heterogeneous computing system where the tasks initially reside on a single computer (the root) in...
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In this paper, we consider the task allocation problem for computing a large set of equal-sized independent tasks on a heterogeneous computing system where the tasks initially reside on a single computer (the root) in the system. This problem represents the computation paradigm for a wide range of applications such as SETI@ home and Monte Carlo simulations. We consider the scenario where the systems have a general graph-structured topology and the computers are capable of concurrent communications and overlapping communications with computation. We show that the maximization of system throughput reduces to a standard network flow problem. We then develop a decentralized adaptive algorithm that solves a relaxed form of the standard network flow problem and maximizes the system throughput. This algorithm is then approximated by a simple decentralized protocol to coordinate the resources adaptively. Simulations are conducted to verify the effectiveness of the proposed approach. For both uniformly distributed and power law distributed systems, a close-to-optimal throughput is achieved, and improved performance over a bandwidth-centric heuristic is observed. The adaptivity of the proposed approach is also verified through simulations.
In this paper, inspired by Vicsek's model, two decentralized heading consensus algorithms, WHCA and LBHCA, are proposed. It is proved that, under sonie well-known connectivity assumption, the WHCA can ensure almos...
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ISBN:
(纸本)9787811240559
In this paper, inspired by Vicsek's model, two decentralized heading consensus algorithms, WHCA and LBHCA, are proposed. It is proved that, under sonie well-known connectivity assumption, the WHCA can ensure almost global consensus of the headings except the only situation where they are balanced at the beginning. For the LBHCA, the global heading consensus is guaranteed under,the same connectivity assumption. Simulation results are provided to justify the proposed algorithms.
The dynamic behavior of a network in which information is changing continuously over time requires robust and efficient mechanisms for keeping nodes updated about new information. Gossip protocols are mechanisms for t...
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The dynamic behavior of a network in which information is changing continuously over time requires robust and efficient mechanisms for keeping nodes updated about new information. Gossip protocols are mechanisms for this task in which nodes communicate with one another according to some underlying deterministic or randomized algorithm, exchanging information in each communication step. In a variety of contexts, the use of randomization to propagate information has been found to provide better reliability and scalability than more regimented deterministic approaches. In many settings, such as a cluster of distributed computing hosts, new information is generated at individual nodes, and is most "interesting" to nodes that are nearby. Thus, we propose distance-based propagation bounds as a performance measure for gossip mechanisms: a node at distance d from the origin of a new piece of information should be able to learn about this information with a delay that grows slowly with d, and is independent of the size of the network. For nodes arranged with uniform density in Euclidean space, we present natural gossip mechanisms, called spatial gossip, that satisfy such a guarantee: new information is spread to nodes at distance d, with high probability, in O(log(1+epsilon) d) time steps. Such a bound combines the desirable qualitative features of uniform gossip, in which information is spread with a delay that is logarithmic in the full network size, and deterministic flooding, in which information is spread with a delay that is linear in the distance and independent of the network size. Our mechanisms and their analysis resolve a conjecture of Demers et al. [1987]. We further show an application of our gossip mechanisms to a basic resource location problem, in which nodes seek to rapidly learn of the nearest copy of a resource in a network. This problem, which is of considerable practical importance, can be solved by a very simple protocol using Spatial Gossip, whereas we
Internet centers host services for e-banks, e-auctions and other clients. Hosting centers then must allocate servers among clients to maximize revenue. The limited number of servers, costs of reallocating servers, and...
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Internet centers host services for e-banks, e-auctions and other clients. Hosting centers then must allocate servers among clients to maximize revenue. The limited number of servers, costs of reallocating servers, and unpredictability of requests make server allocation optimization difficult. Based on the many similarities between server and honey bee colony forager allocation, we propose a new decentralized honey bee algorithm which dynamically allocates servers to satisfy request loads. We compare it against an omniscient optimality algorithm, a conventional greedy algorithm, and an algorithm that computes omnisciently the optimal static allocation. We evaluate performance on simulated request streams and commercial trace data. Our algorithm performs better than static or greedy for highly variable request loads, but greedy can outperform it under low variability. Honey bee forager allocation, though suboptimal for static food sources, may possess a counterbalancing responsiveness to food source variability.
In distributed database systems, commit protocols are used to ensure the transaction atomicity. In the presence of failures, nonblocking commit protocols can guarantee the transaction atomicity without blocking the tr...
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In distributed database systems, commit protocols are used to ensure the transaction atomicity. In the presence of failures, nonblocking commit protocols can guarantee the transaction atomicity without blocking the transaction execution. A (resilient) decentralized nonblocking commit protocol (RDCP) is proper-ed for distributed database systems. This protocol is based on the hypercube network topology and is 'liub(log(2)(N)) - 2' resilient to node failures (N = number of system-nodes). The number of messages sent among the N nodes is 0(***(2)(2)(N)) which is only a factor of log(2)(N) over the message complexity lower bound 0(***(2)(N)) of decentralized commit protocols. Furthermore, RDCP is an optimistic nonblocking protocol. It aborts the transaction only when some nodes want to abort or some nodes fail before they make local decisions.
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