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Parallel and Distributed Computing, Applications and Technologies (PDCAT), 2011 12th International Conference on

Date 20-22 Oct. 2011

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Displaying Results 1 - 25 of 86
  • [Front cover]

    Page(s): C1
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  • [Title page i]

    Page(s): i
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  • [Title page iii]

    Page(s): iii
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  • [Copyright notice]

    Page(s): iv
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  • Table of contents

    Page(s): v - x
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  • Message from General Chairs

    Page(s): xi
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  • Message from Program Chairs

    Page(s): xii
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  • PDCAT 2011 Conference organization

    Page(s): xiii
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  • PDCAT 2011 Program Committee

    Page(s): xiv
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  • Message from PDGCU 2011 Workshop Chairs

    Page(s): xv
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  • PDGCU 2011 Workshop Organization

    Page(s): xvi
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  • A Fast Incremental Spectral Clustering for Large Data Sets

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (271 KB) |  | HTML iconHTML  

    Spectral clustering is an emerging research topic that has numerous applications, such as data dimension reduction and image segmentation. In spectral clustering, as new data points are added continuously, dynamic data sets are processed in an on-line way to avoid costly re-computation. In this paper, we propose a new representative measure to compress the original data sets and maintain a set of representative points by continuously updating Eigen-system with the incidence vector. According to these extracted points we generate instant cluster labels as new data points arrive. Our method is effective and able to process large data sets due to its low time complexity. Experimental results over various real evolutional data sets show that our method provides fast and relatively accurate results. View full abstract»

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  • Dynamically Accessing Packet Header Fields at High-Speed

    Page(s): 6 - 11
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (254 KB) |  | HTML iconHTML  

    A significant part of packet processing consists of detecting whether certain standard protocol headers are present, where they are located and whether they include optional information. Packet processing programs are on tight time budgets, especially to handle speeds in the gigabits per second (gbps) range. Thus, high-speed mechanisms for finding and accessing headers are critical. Our approach lets users define headers as C-style structures in a high-level language, packetC [1], and specify header locations in terms of offsets from the start of the current packet, which is treated as an array of unsigned bytes. These offsets can be expressed in terms of network layer offsets, constant values, runtime-calculated variables and combinations of all of these. This paper focuses on the principal forms these offset expressions can take and on how our FPGAs (Field Programmable Gate Arrays), compiler and interpreter collectively handle them at runtime. For simple and complex header offset scenarios we provide users with intuitive, high-level ways to describe offsets and provide effective runtime mechanisms to access header fields. View full abstract»

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  • Providing Access Control through Program Transformation

    Page(s): 12 - 17
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (277 KB) |  | HTML iconHTML  

    This paper proposes a scheme that automatically adds access control code to web service programs. The scheme simplifies the tasks of the programmers. It uses a fine-grained access control policy to control the access to data. The proposed scheme is more flexible than existing schemes in setting access control policies on data. The scheme automatically tracks the flow of data in the server programs. Experiments show that the proposed scheme incurs very little overheads. View full abstract»

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  • Guaranteed Scheduling for (m,k)-firm Deadline-Constrained Real-Time Tasks on Multiprocessors

    Page(s): 18 - 23
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (285 KB) |  | HTML iconHTML  

    We present a guaranteed real-time scheduling algorithm for multiple real-time tasks subject to (m,k)-firm deadlines on homogeneous multiprocessors. The scheduling objective of the proposed algorithm is to provide guaranteed performance by bounding the probability of missing (m,k)-firm deadline constraints while improving the probability of deadline satisfactions as much as possible. This goal is established to satisfy the minimum requirements expressed by (m,k)-firm deadlines and simultaneously provide the best possible quality of service. We analytically establish that the proposed algorithm provides assurance on the bounded probability of missing (m,k)-firm constraints. Experimental studies validate our analytical results and confirm the effectiveness and superiority of the proposed scheme in achieving our scheduling objective. View full abstract»

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  • A Distributed Task Migration Scheme for Mesh-Based Chip-Multiprocessors

    Page(s): 24 - 29
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (383 KB) |  | HTML iconHTML  

    A task migration scheme for homogeneous chip multiprocessors (CMP) is presented in this paper. The proposed migration mechanism focuses on the communication sub-system and aims to reduce the total power consumption and latency of the network-on-chip (NoC). In this work, starting from an initial mapping, the tasks migrate to new cores in such a way that the distance between the end-point nodes of high-volume communication flows is reduced. Finding the new place for a task is done in a distributed manner by applying an iterative local search that relies on the local information of each task about its communication demand. The task migration procedure also includes a pre-migration step that aims to produce a high quality (i.e. closer to the optimum point) starting point for the main distributed algorithm. The experimental results under some synthetic and realistic CMP workloads show that this method can effectively adapt the mapping of the tasks to the on-chip communication pattern and improve the power consumption and performance of the on-chip networks. View full abstract»

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  • Network Threat Assessment Based on Alert Verification

    Page(s): 30 - 34
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (284 KB) |  | HTML iconHTML  

    In face of overwhelming alerts produced by firewalls or intrusion detection devices, it is difficult to assess network threats that we face. In this paper, we propose a threat assessment approach to estimate the impact of attacks on network. The approach employs the Common Vulnerability Scoring System to quantitatively assess network threats and further correlates alerts with contextual information to improve the accuracy of assessment. In the case studies, we demonstrate how the approach is applied in real networks. The experimental results show that the approach can make an accurate assessment of network threats. View full abstract»

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  • jMigBSP: Object Migration and Asynchronous One-Sided Communication for BSP Applications

    Page(s): 35 - 38
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (234 KB) |  | HTML iconHTML  

    This paper describes the rationale for developing jMigBSP - a Java programming library that offers object rescheduling. It was designed to work on grid computing environments and offers an interface that follows the BSP (Bulk Synchronous Parallel) style. jMigBSP's main contribution focuses on the rescheduling facility in two different ways: (i) by using migration directives on the application code directly and (ii) through automatic load balancing at middleware level. Especially, this second idea is feasible thanks to the Java's inheritance feature, in which transforms a simple jMigBSP application in a migratable one only by changing a single line of code. In addition, the presented library makes the object interaction easier by providing one-sided message passing directives and hides network latency through asynchronous communications. Finally, a BSP-based FFT application was developed and its execution shows jMigBSP as a competitive library when comparing performance with a C-based library called BSPlib. Besides its user-friendly Java interface, the strengths of jMigBSP also considers the migration tests where it outperforms the time spent with BSPlib. View full abstract»

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  • Computation Pattern Driven Reuse of Manual Optimizations for GPGPUs

    Page(s): 39 - 44
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (424 KB) |  | HTML iconHTML  

    The wide application of General Purpose Graphic Processing Units (GPGPUs) results in large manual efforts on porting and optimizing algorithms on them. However, most existing automatic ways of generating GPGPU code fail to conduct optimization strategies regarding a specific computation and to reuse constantly evolving manual optimizations. In this paper, we present a computation pattern driven approach for computation-specific GPGPU code generation and optimization, which in turn reuses manual optimizations to a certain extent. We suggest language extensions to OpenMP, high-level data structure attributes, in order to assist the process of computation pattern matching and to help give users intuitive performance tuning parameters in the view of data structure attributes. We illustrate the feasibility of this approach through three important computation dwarfs, which are dense matrix, sparse matrix, and structured mesh computation in scientific computing. We also build a prototype OpenMP-to-CUDA translator that consists of computation pattern recognition and code template instantiation. The experimental results demonstrate the performance benefits of computation pattern driven method. To our best knowledge, it is the first work on reusing manual optimizations for GPGPUs with computation pattern driven approach. View full abstract»

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  • Reference metadata extraction from scientific papers

    Page(s): 45 - 49
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (315 KB) |  | HTML iconHTML  

    Bibliographical information of scientific papers is of great value since the Science Citation Index is introduced to measure research impact. Most scientific documents available on the web are unstructured or semi-structured, and the automatic reference metadata extraction process becomes an important task. This paper describes a framework for automatic reference metadata extraction from scientific papers. Our system can extract title, author, journal, volume, year, and page from scientific papers in PDF. We utilize a document metadata knowledge base to guide the reference metadata extraction process. The experiment results show that our system achieves a high accuracy. View full abstract»

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  • A Social Network-Based Information Dissemination Scheme

    Page(s): 50 - 55
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (330 KB) |  | HTML iconHTML  

    Handheld devices can use the Bluetooth technology to exchange information with other. This feature allows that handheld devices to be utilized in disseminating information. A scheme for disseminating information using the handheld devices is proposed. The scheme uses both social network analysis and user activity analysis to deliver information to people who might be interested in the information. To encourage people to participate in disseminating information, the scheme uses an incentive mechanism and the integer programming technique to maximize the benefit that people can gain by passing other people's information. Some experiments were carried out to compare the effectiveness of the proposed scheme with other schemes. View full abstract»

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  • Resistence against Malicious Collectives in BubbleTrust

    Page(s): 56 - 61
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (503 KB) |  | HTML iconHTML  

    Malicious collectives represent one of the biggest threats for secured P2P applications. In our previous work, we proposed a trust management system called Bubble Trust targeting this problem. In this paper, we investigate the most common malicious strategies as well as the resistance the Bubble Trust uses against them. We created the simulation framework suitable for testing other TMSs in the same scenarios. Our analysis shows that the success of malicious peers in the Bubble Trust depends mainly on the amount of benefit provided to the network and that the analyzed malicious strategies cannot menace the contribution provided by the P2P network. View full abstract»

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  • XunleiProbe: A Sensitive and Accurate Probing on a Large-Scale P2SP System

    Page(s): 62 - 67
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (879 KB) |  | HTML iconHTML  

    Xunlei [1] is a new P2P content distribution system which is popular in China. It composes traditional HTTP/FTP downloading and P2P content distribution features which attract many people including researchers. Xunlei's network is Bit Torrent-like and the measurement is more difficult than other P2P networks [2]. There are many constrains on Xunlei tracker, so we can not obtain information from tracker easily. Besides this, the measurement will encounter some challenges that skew the results. Most of previous works on Bit Torrent system are based on tracker logs. However, we can not obtain tracker logs of Xunlei. As far as we know, there is no proposal about precise and detailed measurement method that probes the network directly in this area. Face to the challenges, we analyze the constrains that appear in most Bit Torrent-like systems and propose a stratified random selection model to describe the behavior of tracker. Based on the model, we design a measurement tool called XunleiProbe. With the help of our solutions that increase the accuracy of our results, we measure a popular swarm for about 22 hours. The results show that the average peer coverage of our tool can reach about 93%. View full abstract»

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  • A Runtime Fault Detection Method for HPC Cluster

    Page(s): 68 - 72
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (252 KB) |  | HTML iconHTML  

    As the number of nodes keeps increasing, faults have become commonplace for HPC cluster. For fast recovery from faults, the fault detection method is necessary. Based on the usage patterns of HPC cluster, a automatic runtime fault detection mechanism is proposed in this paper: First, the normal activities for nodes in HPC cluster are modeled using runtime state by clustering analysis, Second, the fault detection process is implemented by comparing the current runtime state of nodes with normal activity models. A fault alarm is made immediately when the current runtime state deviates from the normal activity models. In the experiments, the faults are simulated by fault injection methods and the experimental results show that the runtime fault detection method in this paper can detect faults with high accuracy. View full abstract»

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  • A Multi-constraint Preemption Algorithm for Parallel Job Scheduling

    Page(s): 73 - 78
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (258 KB) |  | HTML iconHTML  

    Using effective scheduling strategies to improve turnaround time, slowdown, and utilization is an important consideration in large supercomputing environments. Since such machines have traditionally used non-preemption strategies to accommodate multiple jobs at the same time, a number of questions remain unanswered regarding the practical effect of preemptive scheduling. In this paper, we first discuss how to improve the turnaround time, slowdown, and utilization using an appropriate suspension criterion. We then develop a new multi-constraint preemptive scheduling algorithm (MCPS). Finally, we describe the experiments on a simulator with several realistic workloads. The experimental results show that MCPS is better than the conventional no-preemption strategies, and outperforms other preemptive scheduling strategies by its balanced performance. View full abstract»

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