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Parallel and Distributed Systems, IEEE Transactions on

Issue 3 • Date March 2005

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Displaying Results 1 - 13 of 13
  • [Front cover]

    Publication Year: 2005 , Page(s): c1
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  • [Inside front cover]

    Publication Year: 2005 , Page(s): c2
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  • Efficient algorithms for the all nearest neighbor and closest pair problems on the linear array with a reconfigurable pipelined bus system

    Publication Year: 2005 , Page(s): 193 - 206
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1256 KB) |  | HTML iconHTML  

    We present two O(1)-time algorithms for solving the 2D all nearest neighbor (2D_ANN) problem, the 2D closest pair (2D_CP) problem, the 3D all nearest neighbor (3D_ANN) problem and the 3D-closest pair (3D_CP) problem of n points on the linear array with a reconfigurable pipelined bus system (LARPBS) from the computational geometry perspective. The first O(1) time algorithm, which invokes the ANN properties (introduced in this paper) only once, can solve the 2D_ANN and 2D_CP problems of n points on an LARPBS of size 1/2n53+c/, and the 3D_ANN and 3D_CP problems pf n points on an LARPBS of size 1/2n74+c/, where 0 < ε = 1/2c+1-1 ≪ 1, c is a constant and positive integer. The second O(1) time algorithm, which recursively invokes the ANN properties k times, can solve the kD_ANN, and kD_CP problems of n points on an LARPBS of size 1/2n32+c/, where k = 2 or 3, 0 < ε = 1/2n+1-1 ≪ 1, and c is a constant and positive integer. To the best of our knowledge, all results derived above are the best O(1) time ANN algorithms known. View full abstract»

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  • Scheduling divisible loads on star and tree networks: results and open problems

    Publication Year: 2005 , Page(s): 207 - 218
    Cited by:  Papers (45)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (648 KB) |  | HTML iconHTML  

    Many applications in scientific and engineering domains are structured as large numbers of independent tasks with low granularity. These applications are thus amenable to straightforward parallelization, typically in master-worker fashion, provided that efficient scheduling strategies are available. Such applications have been called divisible-loads because a scheduler may divide the computation among worker processes arbitrarily, both in terms of number of tasks and of task sizes. Divisible load scheduling has been an active area of research for the last 15 years. A vast literature offers results and scheduling algorithms for various models of the underlying distributed computing platform. Broad surveys are available that report on, accomplishments in the field. By contrast, We propose a unified theoretical perspective that synthesizes previously published results, several novel results, and open questions, in a view to foster hover divisible load scheduling research. Specifically, we discuss both one-round and multiround algorithms, and we restrict our scope to the popular star and tree network topologies, which we study with both linear and affine cost models for communication and computation. View full abstract»

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  • Workload-aware load balancing for clustered Web servers

    Publication Year: 2005 , Page(s): 219 - 233
    Cited by:  Papers (51)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2128 KB) |  | HTML iconHTML  

    We focus on load balancing policies for homogeneous clustered Web servers that tune their parameters on-the-fly to adapt to changes in the arrival rates and service times of incoming requests. The proposed scheduling policy, ADAPTLOAD, monitors the incoming workload and self-adjusts its balancing parameters according to changes in the operational environment such as rapid fluctuations in the arrival rates or document popularity. Using actual traces from the 1998 World Cup Web site, we conduct a detailed characterization of the workload demands and demonstrate how online workload monitoring can play a significant part in meeting the performance challenges of robust policy design. We show that the proposed load, balancing policy based on statistical information derived from recent workload history provides similar performance benefits as locality-aware allocation schemes, without requiring locality data. Extensive experimentation indicates that ADAPTLOAD results in an effective scheme, even when servers must support both static and dynamic Web pages. View full abstract»

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  • A complete compiler approach to auto-parallelizing C programs for multi-DSP systems

    Publication Year: 2005 , Page(s): 234 - 245
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1136 KB) |  | HTML iconHTML  

    Auto-parallelizing compilers for embedded applications have been unsuccessful due to the widespread use of pointer arithmetic and the complex memory model of multiple-address space digital signal processors (DSPs). This work develops, for the first time, a complete auto-parallelization approach, which overcomes these issues. It first combines a pointer conversion technique with a new modulo elimination transformation for program recovery enabling later parallelization stages. Next, it integrates a novel data transformation technique that exposes the processor location of partitioned data. When this is combined with a new address resolution mechanism, it generates efficient programs that run on multiple address spaces without using message passing. Furthermore, as DSPs do not possess any data cache structure, an optimization is presented which transforms the program to both exploit remote data locality and local memory bandwidth. This parallelization approach is applied to the DSPstone and UTDSP benchmark suites, giving an average speedup of 3.78 on four analog devices TigerSHARC TS-101 processors. View full abstract»

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  • Peer-to-peer data preservation through storage auctions

    Publication Year: 2005 , Page(s): 246 - 257
    Cited by:  Papers (5)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (672 KB) |  | HTML iconHTML  

    Digital archives protect important data collections from failures by making multiple copies at other archives, so that there are always several good copies of a collection. In a cooperative replication network, sites "trade" space, so that each site contributes storage resources to the system and uses storage resources at other sites. Here, we examine bid trading: a mechanism where sites conduct auctions to determine who to trade with. A local site wishing to make a copy of a collection announces how much remote space is needed, and accepts bids for how much of its own space the local site must "pay" to acquire that remote space. We define a spectrum of trading scenarios, ranging from a network of archives and digital libraries that trust each other, to a scenario where sites do as they please, including breaking the rules. Then, we focus on developing techniques for the scenarios where sites trust each other, although we discuss issues that may arise if sites are greedy or malicious. We examine the best policies for determining when to call auctions and how much to bid, as well as the effects of "maverick" sites that behave differently than other sites. Simulations of auction and trading sessions indicate that bid trading can allow sites to achieve higher reliability than the alternative: a system where sites trade equal amounts of space without bidding. View full abstract»

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  • Time-constrained failure diagnosis in distributed embedded systems: application to actuator diagnosis

    Publication Year: 2005 , Page(s): 258 - 270
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1752 KB) |  | HTML iconHTML  

    Advanced automotive control applications such as steer-by-wire are typically implemented as distributed systems comprising many embedded processors, sensors, and actuators interacting via a communication bus. They have severe cost constraints, but demand a high level of safety and performance. Motivated by the need for timely diagnosis of faulty actuators in such systems, we present a method to achieve distributed failure diagnosis under deadline and resource constraints. Actuators are diagnosed in distributed fashion by processors to provide a global view of their fault status. The integration of software-based tests for actuator diagnosis within the overall control application is studied. These tests are implemented using analytical redundancy and execute concurrently with the control tasks. The test scheduling problem is then formulated and solved to guarantee actuator diagnosis within designer-specified deadlines while meeting control performance goals. As a secondary objective, the scheduling algorithm also reduces the number of processors required for diagnosis. We demonstrate the practicality of the proposed diagnosis approach by applying it to a steer-by-wire example to identify failed actuators in timely fashion. View full abstract»

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  • The impact of incorrectly speculated memory operations in a multithreaded architecture

    Publication Year: 2005 , Page(s): 271 - 285
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1616 KB) |  | HTML iconHTML  

    The speculated execution of threads in a multithreaded architecture, plus the branch prediction used in each thread execution unit, allows many instructions to be executed speculatively, that is, before it is known whether they actually needed by the program. In this study, we examine how the load instructions executed on what turn out to be incorrectly executed program paths impact the memory system performance. We find that incorrect speculation (wrong execution) on the instruction and thread-level provides an indirect prefetching effect for the later correct execution paths and threads. By continuing to execute the mispredicted load instructions even after the instruction or thread-level control speculation is known to be incorrect, the cache misses observed on the correctly executed paths can be reduced by 16 to 73 percent, with an average reduction of 45 percent. However, we also find that these extra loads can increase the amount of memory traffic and can pollute the cache. We introduce the small, fully associative wrong execution cache (WEC) to eliminate the potential pollution that can be caused by the execution of the mispredicted load instructions. Our simulation results show that the WEC can improve the performance of a concurrent multithreaded architecture up to 18.5 percent on the benchmark programs tested, with an average improvement of 9.7 percent, due to the reductions in the number of cache misses. View full abstract»

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  • Additions to 2004 Annual Index

    Publication Year: 2005 , Page(s): 286 - 287
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  • Call for Papers for Special Issue on High Performance Computational Biology

    Publication Year: 2005 , Page(s): 288
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  • TPDS Information for authors

    Publication Year: 2005 , Page(s): c3
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  • [Back cover]

    Publication Year: 2005 , Page(s): c4
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Aims & Scope

IEEE Transactions on Parallel and Distributed Systems (TPDS) is published monthly. It publishes a range of papers, comments on previously published papers, and survey articles that deal with the parallel and distributed systems research areas of current importance to our readers.

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Meet Our Editors

Editor-in-Chief
David Bader
College of Computing
Georgia Institute of Technology