并行密码体制的构造

如何构造并行密码体制是值得关心的重要问题,也为构造与传统密码不同的密码体制开辟了 一个新的思路.分析了串行环境和并行环境的内在不同点,根据并行环境的特征,基于并行复 杂性理论提出一系列构造并行密码体制的基本理论和要求.     

并行推理任务的分配方法及其实验分析

如何将并行推理任务分配到并行推理部件上去是解决并行推理系统的执行功效的一个重要问题。本文对已提出的三种分配策略进行实验分析并对我们提出的一个新的策略进行理论和实验分析。     

并行构件技术研究综述

并行构件技术作为并行软件工程的主要内容之一,对提高并行计算软件的生产率具有重要意义,也是并行软件工程的重要研究内容。并行构件技术研究现状包含并行构件模型、并行构件体系结构规范、并行构件框架3个方面。并行构件、接口、框架的定义和实现是区分不同并行构件体系结构规范的主要标准。如何在实现并行构件复用性的同时提高并行构件组成的应用系统性能,是这些技术发展的共同思想。单构件多数据、多构件多数据编程模型、多语言互操作技术、并行远程方法调用、MxN问题的解决方法、不同模型构件间的互操作都是并行构件领域的研究成果。并行构件技术的发展方向是开展对多语言互操作、性能预测、自适应构件、构件模型的互操作、多核硬件上的并行构件体系结构技术的研究。     

MPI通信代码自动生成算法

对于高性能并行计算机而言，如何由给出的计算、数据划分信息及精确数组数据流分析信息自动生成并行化代码是实现串行程序并行化的一个重要问题。根据Saman P.Amarasinghe和Lam的定理，实现了一种并行化识别工具中MPI（Message Passing Interface）并行化代码自动生成技术的算法，并对该算法的性能进行分析。     

支持数据重分布通信的计算和数据分解算法

对于分布内存体系结构的并行计算机而言，如何对计算和数据进行合理划分以增加数据本地化减少处理器间的通信是提高其并行性能的关键，但在数据划分过程中，重分布通信有时不可避免，如何进行合理的数据和计算划分以减少通信并最大限度的利用程序的并行性是并行编译中的一个重要问题。该文主要讨论了一种支持数据重分布的自动进行计算和数据划分的算法。     

并行文件系统研究综述

对于运行在机群上的一类I/O密集型应用,I/O成为整个系统的瓶颈,并行文件系统是解决I/O瓶颈问题的重要方法.但如何实现高性价比且高可用的并行文件系统,目前还没有一个成形完整的解决方案.本文阐述了并行文件系统的功能和模型,对现存的并行文件系统从三个不同的角度进行了分类,详细分析了设计并行文件系统的5个关键技术,分析评价了具有代表性的并行文件系统优缺点,最后讨论了进一步的研究工作.     

有限差分法的并行化计算实现

有限差分法是求解偏微分方程近似解的一种重要的数值方法。并行化计算可提高复杂计算问题的效率,二维场中拉普拉斯方程的差分格式非常适合并行化方法的计算。如何将串行部分并行化以提高大规模计算的效率,MPI（消息传递接口）是实现并行程序设计的标准之一。虚拟进程（MPI_PROC_NULL）是MPI中的假想进程,它的引用可简化MPI编程中的通信部分,引入虚拟进程编写代码,可实现有限差分方法的并行化计算。     

分布式计算环境下的并行设计系统

在并行设计过程中，如何把各个部门的设计信息有效的集成是需要解决的重要问题。该文中的并行设计系统利用面向对象技术描述各个部门建模的特征信息，建立起各个部门的类库。而各个部门的建模系统通过基于CORBA的分布式系统的支持可以方便的获取远端或异构建模系统的特征信息，也可以调用异构建模系统的应用程序，从而实现并行设计。     

声波数值模拟中的多核并行方法研究

波动方程数值模拟普遍存在计算量大的问题,如何根据波动方程有限差分方法的特点开展并行化方法研究是适应微机多核发展的必然趋势。结合波动方程数值模拟中的多层循环嵌套问题和OpenMP的特点,通过确定循环体并行顺序、减少串行环节、合并循环体、准确设置制导语句以及线程绑定优化等方法有助于实现微机多核的高效并行。针对波动方程特点的多核并行不仅有助于提高单机计算效率,对于提高计算机集群上常用的MPI+OpenMP混合并行效率也具有重要意义。     

一种基于群机系统的对象并行模型的探讨与实践

对象并行是面向对象技术与并行技术相结合的产物。如何在面向对象语言Ｃ＋＋中实现数据并行、任务并行等并行思想,是当前亟待解决的一个问题。该文探讨了在群机系统上进行对象并行所面临的新问题,并提出了一种新的对象并行模型,给出了在３台ＲＳ６０００工作站上的初步实验结果。     

一个基于图像代数的并行图像处理环境

系统可用性和应用程序可移植性差是许多现有的并行图像处理计算结构难以获得实际应用的重要原因，基于Ritter提出的图像代数理论，研究、实现了一个并行图像处理环境．用户在并行计算结构上进行程序设计时，只需用图像处理环境提供的图像代数运算描述算法即可，处理环境能够根据用户算法的描述，依据一个时间开销模型，自动从并行实现函数库中提取出最优或近似最优的并行代码完成算法的运行，算法的并行实现和并行计算结构的硬件细节对用户透明。     

OpenMP parallelization of agent-based models

Agent-based models, an emerging paradigm of simulation of complex systems, appear very suitable to parallel processing. However, during the parallelization of a simulator of financial markets, we found that some features of these codes highlight non-trivial issues of the present hardware/software platforms for parallel processing. Here we present the results of a series of tests, on different platforms, of simplified codes that reproduce such problems and can be used as a starting point in the search of a possible solution.     

Performance comparison of the CRAY-2 and CRAY X-MP/416 supercomputers

The serial and parallel performance of one of the world's fastest general purpose computers, the CRAY-2, is analyzed using the standard Los Alamos Benchmark Set plus codes adapted for parallel processing. For comparison, architectural and performance data are also given for the CRAY X-MP/416. Factors affecting performance, such as memory bandwidth, size and access speed of memory, and software exploitation of hardware, are examined. The parallel processing environments of both machines are evaluated, and speedup measurements for the parallel codes are given.An earlier version of this paper was presented at Supercomputing '88This work was performed under the auspices of the U.S. Department of Energy.     

制导控制系统的实时多线程软件设计

计算和数据分解是分布主存系统中并行编译的关键,在并行优化编译器的并行识别过程中,许多串行代码无法找到全局一致的分解结果.针对这种情况,该文提出一种融合程序控制流的动态分解算法,增加控制流对分解的影响,使生成的分解结果更适合于后端自动生成的并行代码.实验分析结果表明了该方法的有效性.     

基于融合程序控制流的动态分解算法

计算和数据分解是分布主存系统中并行编译的关键,在并行优化编译器的并行识别过程中,许多串行代码无法找到全局一致的分解结果。针对这种情况,该文提出一种融合程序控制流的动态分解算法,增加控制流对分解的影响,使生成的分解结果更适合于后端自动生成的并行代码。实验分析结果表明了该方法的有效性。     

IDEWEP: Web service for astronomical parallel image deconvolution

Image restoration is a significant process commonly applied in many research fields. In particular, image deconvolution algorithms play a very important role in the research methodology in astrophysics, where recorded images are frequently submitted to deconvolution processes. In this paper, we introduce a novel image deconvolution algorithm that is competitive in terms of the restored image quality when compared to classical approaches. We present parallelizations of this algorithm to make it competitive in terms of processing speeds as well. We also present the image deconvolution web portal (IDEWEP) that, using web services technologies, primarily aims to make this general parallel deconvolution method accessible through a web interface. Both the quality of the restored images and running times of the sequential and parallel version have been successfully tested in several sequential and parallel architectures. The IDEWEP portal greatly eases the access and use of the parallel algorithm in high performance architectures. As a contribution to the scientific community, open source sequential and parallel codes are provided and can be freely downloaded from our web portal.     

Implementing molecular dynamics on hybrid high performance computers – short range forces

The use of accelerators such as graphics processing units (GPUs) has become popular in scientific computing applications due to their low cost, impressive floating-point capabilities, high memory bandwidth, and low electrical power requirements. Hybrid high-performance computers, machines with more than one type of floating-point processor, are now becoming more prevalent due to these advantages. In this work, we discuss several important issues in porting a large molecular dynamics code for use on parallel hybrid machines – (1) choosing a hybrid parallel decomposition that works on central processing units (CPUs) with distributed memory and accelerator cores with shared memory, (2) minimizing the amount of code that must be ported for efficient acceleration, (3) utilizing the available processing power from both multi-core CPUs and accelerators, and (4) choosing a programming model for acceleration. We present our solution to each of these issues for short-range force calculation in the molecular dynamics package LAMMPS, however, the methods can be applied in many molecular dynamics codes. Specifically, we describe algorithms for efficient short range force calculation on hybrid high-performance machines. We describe an approach for dynamic load balancing of work between CPU and accelerator cores. We describe the Geryon library that allows a single code to compile with both CUDA and OpenCL for use on a variety of accelerators. Finally, we present results on a parallel test cluster containing 32 Fermi GPUs and 180 CPU cores.     

Adaptive load balancing of iterative computation on heterogeneous nondedicated systems

Dynamic load balancing in heterogeneous systems is a fundamental research topic in parallel computing due to the high availability of such systems. The efficient utilization of the heterogeneous resources can significantly enhance the performance of the parallel system. At the same time, adapting parallel codes to state-of-the-art parallel computers composed of heterogeneous multinode–multicore processors becomes a very hard task because parallel codes are highly dependent on the parallel architectures. That means that applications must be tailored requiring a great deal of programming effort. We have developed the ALBIC (Adaptive Load Balancing of Iterative Computation) system that allows for the dynamic load balancing of iterative codes in heterogeneous dedicated and nondedicated Linux based systems. In order to validate the system several parallel codes have been analyzed in different scenarios. The results show that the ALBIC approach achieves better performance than the other proposal. This lightweighted library eases porting homogeneous parallel codes to heterogeneous platforms, since the code intrusion is low and the programming effort is quite reduced.     

并行嵌入式系统可视化性能分析工具的设计与实现

随着并行计算在军用、工业技术等领域的广泛应用,更多的用户开始应用并行处理技术解决问题,针对嵌入式多核多处理器平台的并行程序开发也更加普及。并行调试技术是并行程序开发的一个重要环节,调试实时应用程序的过程十分复杂,但是,并行调试环境却相对比较薄弱。文章研究设计了一种基于并行嵌入式实时系统的性能分析工具,只需使用极少的资源便可对应用程序进行跟踪分析,具有较高的性能。     

湍流退化图像并行校正方法

文章对湍流退化图像的双重循环迭代图像复原算法的计算流程进行了分析,将算法的串行计算模式转换为并行模式,提出了基于并行模式的多结点并行处理方法。成功地实现算法的并行计算模式到多结点结构的有效映射,对算法的程序代码进行了有效移植,在多结点系统上运行通过。实验结果表明,不仅提出的并行校正方法有效,而且提高了图像复原处理帧频数。