We describe a tool that implements a set of services to manipulate and store data from a radar network in a transparent way to end users. A major requirement of this system is data availability and reliability. Conseq...
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ISBN:
(纸本)9780769527369
We describe a tool that implements a set of services to manipulate and store data from a radar network in a transparent way to end users. A major requirement of this system is data availability and reliability. Consequently, we have implemented a redundancy schema based on the Information Dispersal Algorithm (IDA). Preliminary results show that the IDA based replication provides better reliability and less storage spending than traditional replication.
In a parallel processing system, a pancake graph is one of the superior topologies for interconnection network because of the small diameter and the high degree. In previous research, fault-tolerant routing using rest...
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ISBN:
(纸本)9781479983346
In a parallel processing system, a pancake graph is one of the superior topologies for interconnection network because of the small diameter and the high degree. In previous research, fault-tolerant routing using restricted global information called safety levels in a pancake graph was proposed. But there are some rooms for improvement. therefore, we propose a fault-tolerant routing algorithm based on improved safety levels to attain higher reachability. In addition, we estimated the proposed method in time and space complexities, and carried out a computer experiment to verify its effectiveness.
Energy consumption has increasingly become a serious problem in contemporary data centers. the electricity bill contributes a significant fraction of the Total Cost of Ownership (TCO), and it has been predicted to inc...
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ISBN:
(纸本)9780769548791
Energy consumption has increasingly become a serious problem in contemporary data centers. the electricity bill contributes a significant fraction of the Total Cost of Ownership (TCO), and it has been predicted to increase at an even faster pace in the following years. In an attempt to reduce the energy consumption in cloud infrastructures, we propose REST, an energy-efficient cloud storage built upon an open source cluster-based object store similar to GFS. It achieves high energy-efficiency by cleverly exploiting the redundancy and its asymmetric accesses existing in the system without compromising inherent well-established mechanisms, while maintaining reasonable performance level. By slightly altering the data-layout policy, REST can safely keep a large amount of redundant storage nodes in standby mode or even powered off most of the time. Deploying a sophisticated real-time workload monitor, it provides flexibility to power up standby or powered down nodes to accommodate the variations in workloads. In addition, trade-offs between energy and performance can be conveniently made by simply adjusting a trade-off metric in REST. the FileBench experimental results have demonstrated that power savings can be as high as 29%, still providing comparable or even better performance.
State-of-the-art high-throughput sequencing instruments decipher in excess of a billion short genomic fragments per run. the output sequences are referred to as reads. these read datasets facilitate a wide variety of ...
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ISBN:
(纸本)9781450347228
State-of-the-art high-throughput sequencing instruments decipher in excess of a billion short genomic fragments per run. the output sequences are referred to as reads. these read datasets facilitate a wide variety of analyses withapplications in areas such as genomics, metagenomics, and transcriptomics. Owing to the large size of the read datasets, such analyses are often compute and memory intensive. In this paper, we present a parallel algorithm for partitioning large-scale read datasets in order to facilitate distributed-memory parallel analyses. During the process of partitioning the read datasets, we construct and partition the associated de Bruijn graph in parallel. this allows applicationsthat make use of a variant of the de Bruijn graph, such as de novo assembly, to directly leverage the generated de Bruijn graph partitions. In addition, we propose a mechanism for evaluating the quality of the generated partitions of reads and demonstrate that our algorithm produces high quality partitions. Our implementation is available at ***/ParBLiSS/read_partitioning.
Various kinds of distributedapplications are realized in object-based frameworks. Object-based technologies are used to design, applications and enhance the interoperability among applications. In addition to realizi...
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ISBN:
(纸本)0769511538
Various kinds of distributedapplications are realized in object-based frameworks. Object-based technologies are used to design, applications and enhance the interoperability among applications. In addition to realizing the interoperability, the system is required to be secure. the secure system is required to not only protect objects from illegally manipulated but also illegal information flow among objects. In this paper, we discuss a role-based access control model in the object-based systems and how to resolve illegal information flour in the roles. We define a safe set of roles where no illegal information flow occurs. We discuss an algorithm to check if illegal information flow occurs. In addition, we discuss hour to safely perform transactions belonging to unsafe roles.
parallel programs based on the Divide & Conquer paradigm could be successfully defined in a simple way using powerlists. these parallel recursive data structures and their algebraic theories offer both a methodolo...
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In the past five years, hosts on Internet have multiplied more than five times, and along withthe network's rapid expansion, more and more attention is paid to the challenging task of studying the topology charac...
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ISBN:
(纸本)0780378407
In the past five years, hosts on Internet have multiplied more than five times, and along withthe network's rapid expansion, more and more attention is paid to the challenging task of studying the topology characteristics of Internet infrastructure. Based on the features of Internet topology discovery and practical experience, we present a three-level distributed architecture for Internet router-level routing topology discovering system. We employ an integrated framework for the deployment of the system. We are examining, from a macroscopic point of view, what architecture is appropriate for this-like system, with an emphasis placed on the flexibility in practical work. the architecture enjoys the advantages of a clear train of thought and high modularization. Experiments show that this architecture has an instructive meaning for the development, deployment, and maintenance of Internet topology discovering system.
the main contribution of this paper is to present an efficient parallel sorting "psort" compatible withthe standard qsort. Our parallel sorting "psort" is implemented such that its interface is co...
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ISBN:
(纸本)9781424452910
the main contribution of this paper is to present an efficient parallel sorting "psort" compatible withthe standard qsort. Our parallel sorting "psort" is implemented such that its interface is compatible with "qsort" in C Standard Library. therefore, any application program that uses standard "qsort" can be accelerated by simply replacing "qsort" call by our "psort". Also, "psort" uses standard "qsort" as a "subroutine for local sequential sorting. So, if the performance of "qsort" is improved by anyone in the community, then that of our "psort" is also automatically improved. To evaluate the performance of our "psort", we have implemented our parallel sorting in a Linux server with two Intel quad-core processors (i.e. eight processor cores). the experimental results show that our "psort" is approximately 6 times faster than standard "qsort" using 8 processors. Since the speed up factor cannot be more than 8 if we use 8 cores, our algorithm is close to optimal. Also, as far as we know, no previously published parallel implementations achieve a speed up factor less than 4 using 8 cores.
Assume that each vertex of an arbitrary n-vertex tree T is assigned a nonnegative integer weight. this paper considers partitioning the vertices of tree T into p disjoint clusters such that the total weight of each cl...
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ISBN:
(纸本)9780769548791
Assume that each vertex of an arbitrary n-vertex tree T is assigned a nonnegative integer weight. this paper considers partitioning the vertices of tree T into p disjoint clusters such that the total weight of each cluster is at least l and at most u, where l and u are given integers with lthms for trees only allow that a cluster corresponds to a subtree, our algorithm also considers clusters containing several subtrees as long as these subtrees have the same parent node or their root vertices are adjacent siblings. We call this [l, u] sibling partitioning. We deal with two problems of [l, u] sibling partitioning for a given tree: the minimal partition problem is to find an [l, u] sibling partitioning withthe minimum number of clusters;the p-partition problem is to find an [l, u] sibling partitioning with a given number p of clusters. In this paper, we present the first polynomial-time algorithm to solve the two problems.
nowadays, more and more supercomputers are built on multi-core processors with shared caches. However, the conflict accesses to shared cache from different threads or processes become a performance bottleneck for para...
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ISBN:
(纸本)9781424452910
nowadays, more and more supercomputers are built on multi-core processors with shared caches. However, the conflict accesses to shared cache from different threads or processes become a performance bottleneck for parallelapplications. Cache partitioning can be used to allocate cache resources for different processes exclusively according to the demands of the processes. Conflicted accesses are avoided by restricting cache accesses to distinct private part of shared caches. this paper studies the problem of shared cache partition for balanced MPI parallelapplications in CMP architecture, presenting the performance oriented cache partitioning framework, including Spatial-Level Cache Partitioning(SLCP), Time-level Cache Partitioning(TLCP) and the evaluation of them. We evaluate SLCP and TLCP based on a quad-core simulator. Experiment shows that the SLCP and TLCP outperforms traditional LRU cache replacement policy in IPC throughput and miss rate metric. Specifically, for large workloads, TLCP outperforms LRU by up to 20% and on average 8.7%.
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