this paper concerns speculative parallelization as a method of improving computations efficiency and also as a method of reducing the problem solving time with reference to its sequential version. Speculative parallel...
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ISBN:
(纸本)9780769534725
this paper concerns speculative parallelization as a method of improving computations efficiency and also as a method of reducing the problem solving time with reference to its sequential version. Speculative parallelization is proposed or a particular class of problems, described as recursive functions taking values from finite sets. It refers to speculative execution of consecutive iteration steps, each of which, except the first one, depends on the preceding iteration step yet before it ends. Assuming that in the sequential version one iteration is performed in one linear execution time step (hereinafter referred to as computational step), then the aim of the speculative parallelization is the reduction of the total number of computational steps and thus execution of more than one iteration in one time step. the essence of the problem is that we assume some mapping schemes of arguments into the set of possible values of the function in speculative computing, i.e. there exists precise information about the possible values that the function can take for particular arguments. this paper presents simulation results for the chosen mapping schemes, illustrating how the number of steps, required to compute the value of the function for the given argument, depends on the structure of the mapping scheme and the number of used parallelthreads.
Heterogeneity and complexity of distributedcomputing increases rapidly as high speed processors are widely available. In modern computing environment, resources are dynamic, heterogeneous, geographically spread over ...
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ISBN:
(纸本)9781509015603
Heterogeneity and complexity of distributedcomputing increases rapidly as high speed processors are widely available. In modern computing environment, resources are dynamic, heterogeneous, geographically spread over different computational domains and connected through different capacity of high speed communication links. In a large distributed environment a modular program can be considered as a set of loosely coupled interacting modules/tasks (since all the modules/tasks are considered as simultaneously and independently executable) and represented by task interaction graph (TIG) model. parallel execution of these interacting modules/tasks is highly preferred to reduce the overall completion time of a program. During parallel execution of tasks, the communication overhead due to message passing may increase the cost of parallel execution. parallel execution of tasks is chosen if and only if parallel execution cost together with communication overhead is less than serial execution cost. So, resources are to be allocated such that advantage of parallel execution is maintained. In this paper, for any task and resource graph, we propose a heuristics based approach to find out an optimal number of tasks that can be executed in parallel on a set of resources where they can be executed
Grid technology allows resource sharing among several entities, but selecting the best resource to run a specific job remains one of its main problems. the challenges for the best resource selection involve analysis o...
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ISBN:
(纸本)9780769528335
Grid technology allows resource sharing among several entities, but selecting the best resource to run a specific job remains one of its main problems. the challenges for the best resource selection involve analysis of several factors such as prediction time to run a job, access restriction to resources, and cost to use resources. this paper presents a resource selection model using decision theory for combining these influential factors in the resource selection process. the model is based on a multi-attribute utility function that maximizes the user preference. this model forms part of a multi-agent system deploying distributed and parallel processing for job execution prediction, access policy verification, and resource selection models. All models of this paper were verified through experiments using real machines. they have presented appropriate functional behaviors and positive performance results.
In this paper we consider the frameworks of Process Algebra and I/O Automata and we apply both towards the verification of a distributed leader-election protocol. Based on the two experiences we evaluate the approache...
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this paper describes the parallelization (gridification) of the phylogenetic pack-age PHYLIP on a Large Scale distributed System termed XtremWeb-CH. PHYLIP is a pack-age of programs for inferring phylogenies (evolutio...
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ISBN:
(纸本)9780769528335
this paper describes the parallelization (gridification) of the phylogenetic pack-age PHYLIP on a Large Scale distributed System termed XtremWeb-CH. PHYLIP is a pack-age of programs for inferring phylogenies (evolutionary trees). It is the most widely-distributed phylogeny-package. PHYLIP has been used to build the largest number of published trees. It's known that some modules of PHYLIP are CPU time consuming;their sequential version can not be applied to a large number of sequences. XtremWeb-CH (XWCH) is a software system that makes it easier for scientists and industrials to deploy and execute their parallel and distributed applications on a public-resource computing infrastructure. Universities, research centres and private companies can create their own XWCH platform while anonymous PC owners can participate to these platforms. they can specify how and when their resources could be used. the objective of XWCH is to develop a real High Performance Peer-To-Peer platform with a distributed scheduling and communication system. the main idea is to build a completely symmetric model where nodes can be providers and consumers at the same time. In this paper we describe the porting, deployment, and execution of some PHYLIP modules on the XWCH platform. the parallelized version of PHYLIP is used to generate evolutionary tree related to HIV viruses.
Weighted Label Propagation Algorithm with Probability threshold (P-WLPA) with typical serial execution prototype is proposed to be applied in data classification. Meanwhile on distributedcomputing system Spark, paral...
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ISBN:
(纸本)9781479944194
Weighted Label Propagation Algorithm with Probability threshold (P-WLPA) with typical serial execution prototype is proposed to be applied in data classification. Meanwhile on distributedcomputing system Spark, parallel P-WLPA algorithm for labeling big data is conducted. the algorithm sets prior conditions when configuring undirected graph and optimizes parameter learning in P-WLPA process. through experiments, we analyze the relationship between Iterations for convergence, sample stability threshold and error rate. Finally Serial and parallel P-WLPA performance comparision demonstrates the feasibility and efficiency of the parallel P-WLPA algorithm implementation on Spark.
gLite is one of the largest distributedcomputing infrastructures in operation. It provides access to hundreds of different clusters - all installed and maintained in different ways. this paper analyses the difficulti...
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ISBN:
(纸本)9780769539393
gLite is one of the largest distributedcomputing infrastructures in operation. It provides access to hundreds of different clusters - all installed and maintained in different ways. this paper analyses the difficulties which users typically experience when moving from their own workstation via clusters or supercomputers to the grid. Based on that analysis, this paper presents tools, which helps to overcome this gap and introduces an advanced commandline interface to the grid.
distributed storage systems apply erasure-tolerant codes to guarantee reliable access to data despite failures of storage resources. While many codes can be mapped to XOR operations and efficiently implemented on comm...
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this paper presents a Proportional Resonant (PR) based circulating current controller for four parallel interleaved Voltage Source Converters (VSCs). Interleaving the carrier signals will cause a switching frequency c...
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ISBN:
(纸本)9781467386173
this paper presents a Proportional Resonant (PR) based circulating current controller for four parallel interleaved Voltage Source Converters (VSCs). Interleaving the carrier signals will cause a switching frequency circulating current to flow between the VSCs. therefore, to suppress these circulating currents the VSCs are interconnected through Coupled Inductors (CIs), which form a whiffletree configuration, and they are used to suppress the switching frequency circulating current. On the other hand, the CIs are highly sensitive to fundamental frequency circulating currents, which may saturate them. Hence, a circulating current controller is required, which effectively controls the fundamental component of the circulating current. Furthermore, the circulating current is sampled using a special technique, which does not require any additional. the effectiveness of the design methodology and the performance of the circulating current controller are verified by simulation and experimental results as well.
the proceedings contain 128 papers. the topics discussed include: C parallelizing compiler on local-net work- based computer environment;OCCAM prototyping of massively parallel applications from colored Petri-nets;per...
ISBN:
(纸本)0818634421
the proceedings contain 128 papers. the topics discussed include: C parallelizing compiler on local-net work- based computer environment;OCCAM prototyping of massively parallel applications from colored Petri-nets;performance characteristics of the iPSC/SSO and CM-2 I/O systems;automatic parallelization of LINPACK routines on distributed memory parallel processors;transformation of doacross loops on distributed memory systems;an efficient atomic multicast protocol for client-server models;a new horizon for sorting on mesh architectures;mapping of uniform dependence algorithm onto fixed size processor arrays;and towards understanding block partitioning for sparse Cholesky factorization.
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