10G以太网帧同步系统的研究

为减少大规模并行帧同步系统的面积开销,提出了一种系统设计方案——多比较器．单计数器并行帧同步系统(MCSC-PFSS)。该方案基于对连续性的判别,在减小面积开销的同时达到了接近现有最好的帧同步系统的性能。同时,对所涉及到的各种并行帧同步方案的性能进行了理论分析,计算机仿真以及逻辑综合。结果表明,本文提出的方案用于10G以太网中66B比特流的帧同步具有良好的效果。     

水下声数据高速传输中的一种帧同步系统

在高速水下声数据的时分多路传输中，对帧同步系统的性能有特殊的要求。本文结合一种实用的多种水下声数据传输系统，对其帧同步系统设计作了详细介绍，并指出了实现快速帧同步和提高抗干扰的方法，给出了具体的实现方案，理论分析和实验结果都表明了该方法的可行性。     

图样调制跳频系统的帧同步算法与性能分析

为提高跳频通信的抗干扰性能,设计一种新的短波跳频通信技术——图样调制跳频(pattern modulation frequency hopping,PMFH)系统。该系统将跳点分组,以载波发射的相对位置代表信息比特。通过增加调制域的冗余度和基带信号能量,以频带和功率资源换取信噪比,同时保护了跳频序列。为克服跳同步后静默时间对信号帧同步的影响,设计同步字检测方案和多图样匹配方案。结果证明:多图样匹配方案的性能较好,在信噪比大于0dB时,7位Gold图样的帧同步概率不小于80%,31位Gold图样的帧同步概率不小于95%,图样调制跳频技术使跳频通信在恶劣信道中的可靠性显著提高。     

Eiguanxi一种无线通信系统中改进的帧同步方法

同步问题是MIMOOVDM系统的关键问题。本文对基于正交帧头的同步方案提出厂改进．将自适应门限的帧头判决门限方案引入其中。仿真表明，这种改进的方案在不增加系统复杂度的前提下，提高了帧同步的正确检测率，保证了同步的稳定性和快速性。     

变排量非对称轴向柱塞泵抗扰控制及并行整定方法

针对变排量非对称轴向柱塞泵因斜盘振荡严重而引起流量脉动较大的问题,提出将变量阻力矩视作干扰信号,采用抗扰控制算法来提高其变排量控制性能。通过SimulationX和Simulink平台联合仿真,对比在不同频率的变量阻力矩作用时常规PID（proportion integration differentiation,比例积分微分）控制、指数收敛干扰观测器控制、非线性PID控制、自抗扰控制和滑模控制下变排量非对称轴向柱塞泵斜盘角度的响应特性,以得到最合适的抗扰控制算法。在此基础上,提出一种基于粒子群优化（particle swarm optimization, PSO）的控制参数并行整定方法。仿真结果表明,在10,20和100 Hz干扰信号的作用下,滑模控制下变排量非对称轴向柱塞泵斜盘角度的波动量为常规PID控制下的1.7%,2.2%和23.0%,说明滑模控制算法能大幅减小斜盘振荡和流量脉动。基于PSO的控制参数并行整定方法有效地减小了滑模控制的跟踪误差,整定后的最大超调量减小了87.5%;且该并行整定方法可脱离专业仿真软件,与SimulationX平台仿真相比,其仿真效率提高了10倍以上。研究结果对常规液压控制系统的仿真优化有一定参考价值。     

用于计算机总线并行互连的高速光互链路

设计和实现了基于计算机ＰＣＩ总线的高速光互连链路。链路的网络接口卡具有３２位并行输入／输出接口，中间采用时分复用同步传输技术，在一根光纤中实现了ＰＣＩ癖线数据的虚拟并行传输。链路的最高数据传输速率为１２５０Ｍｂｉｔ／ｓ，多模光纤时最大传输距离为６４０ｍ，在１０米传输距离时，通信延迟低于２００ｎｓ。     

基于云计算的并行化自动测试系统设计

为适应航天器批产化测试的要求,提高测试效率,本文以云计算支撑平台为核心设计了适用于航天器测试需要的并行化自动测试系统.系统基于vSphere云计算软件构建系统资源的集群环境,利用模块化思想构建了测试设计子平台、核心数据处理子平台、通用测试设备子平台、自动化测试执行子平台、测试信息存储子平台、信息评估分析子平台等六大子平台.通过对多台导航接收机进行并行测试,系统实现了测试设计、信息处理、测试执行、接口管理、数据存储、数据评估等全流程测试功能,结果表明:系统提高了产品测试效率,并节约了系统资源.     

用于计算机总线并行互连的高速光互连链路

设计和实现了基于计算机ＰＣＩ总线的高速光互连链路。链路的网络接口卡具有３２位并行输入／输出接口,中间采用时分复用同步传输技术,在一根光纤中实现了ＰＣＩ总线数据的虚拟并行传输。链路的最高数据传输速率为１２５０Ｍｂｉｔ／ｓ,使用多模光纤时最大传输距离为６４０ｍ,在１０米传输距离时,通信延迟低于２００ｎｓ。     

传输斜移对同步并行光传输系统性能的影响

针对一个具体的链路模型,通过计算机仿真分析了传输斜移对同步并行光传输系统性能的影响.光纤中的信号分析在频域中通过快速傅立叶变换(fast fourier transform,FFT)进行.分别计算了单信道误码率以及没有传输斜移和有传输斜移时并行信道总的误码率.计算结果表明,在噪声不是影响系统性能的主要因素时,传输斜移是决定并行光传输系统最大同步传输速率和传输距离的一个重要因素.     

提高IRIG-B码编码器时间同步精度方法的研究

提出了以单片微处理器为核心、辅以高速时间同步单元的电路方案,采用软硬件结合方法,设计并实现了IRIG-B码编码器。经验证,该方案结构简单,成本低,同步精度高,符合电力行业标准,满足电力系统运行要求。     

基于曙光1000A的并行查询核心系统的设计与实现

根据曙光１０００Ａ的特点，提出了查询核心系统的设计方案；经过分析比较，选定了数据划分方法，确定了ＳＱＬ子集。在此基础上，研究了物理库设计、并行事务管理、查询优化器的设计和事务的调度方法，旨在为在曙光１０００Ａ上建造并行数据库系统奠定基础。     

Parallel contact algorithms for nonlinear implicit transient analysis

This paper presents a nonlinear implicit transient formulation for parallel contact analysis. A new lumping algorithm based on the penalty method is developed to enforce contact constraints. This algorithm has the effect of incorporating contact generated connectivity and eliminating ill conditioning in the system stiffness matrix caused by the use of a large penalty parameter. Communication schemes are also developed to facilitate contact searching and enforcement in a parallel environment. Numerical analyses were conducted to verify the accuracy of the proposed algorithm. In addition, several contact simulations are also performed to study the performance of this new algorithm under different circumstances. Efficiency plots are also presented for one of the simulations to evaluate the performance of this parallel implicit contact formulation.This paper is based upon work supported by, or in part by, the U.S. Army Research Office under grant number DAAD19-99-1-0235. The authors also acknowledge support under a DoD HPC Challenge Project.     

Fast Parallel Algorithms for Matrix Reduction to Normal Forms

 We investigate fast parallel algorithms to compute normal forms of matrices and the corresponding transformations. Given a matrix B in ℳ _n,n (K), where K is an arbitrary commutative field, we establish that computing a similarity transformation P such that F=P ^-1 BP is in Frobenius normal form can be done in ?C ² _K . Using a reduction to this first problem, a similar fact is then proved for the Smith normal form S(x) of a polynomial matrix A(x) in ℳ _n,m (K[x]); to compute unimodular matrices U(x) and V(x) such that S(x)=U(x)A(x)V(x) can be done in ?C ² _K . We get that over concrete fields such as the rationals, these problems are in ?C ². Using our previous results we have thus established that the problems of computing transformations over a field extension for the Jordan normal form, and transformations over the input field for the Frobenius and the Smith normal form are all in ?C ² _K . As a corollary we establish a polynomial-time sequential algorithm to compute transformations for the Smith form over K[x]. Received: February 29, 1996; revised version: August 29, 1997     

Parallel implementation of the EFG Method for heat transfer and fluid flow problems

The parallel implementation of the element free Galerkin (EFG) method for heat transfer and fluid flow problems on MIMD type parallel computer is treated. A new parallel algorithm has been proposed in which parallelization is performed by row-wise data distribution among the processors. The codes have been developed in FORTRAN language using MPI message passing library. Two model (one each in heat transfer and fluid flow) problems have been solved to validate the proposed algorithm. The total time, communication time, user time, speedup and efficiency have been estimated for heat transfer and fluid flow problems. For eight processors, the speedup and efficiency are obtained to be 7.11 and 88.87% respectively in heat transfer problems for a data size of N=2,116 whereas 7.20 and 90.04% respectively in fluid flow problems for a data size of N=2,378.     

高效并行算法的设计与实现

在三类不同体系结构并行多机系统上，通过求解大型稀疏线性代数方程组的高效并行迭代算法的设计与实现。     

基于PN的并行程序设计方法

首先分析了并行程序的特点，在此基础上，提出并行程序设计的若干Ｐｅｔｒｉ网方法。这些在一定程度上助于减少或避免一些逻辑错误的出现，从而减轻了程序验证的负担。最后通过例子显示了这些方法的作用。     

并行程序设计环境研究

从并行程序辅助设计环境的角度，对并行软件开发这个并行处理技术中的“瓶颈”问题进行了探讨。就一个针对３ＬＦＯＲＴＲＡＮ的实用系统ＰＰＥ，介绍了其设计思想和基本构成，说明了该系统的主要特点，提出了解决并行程序设计环境实现中若干关键技术的新理论和新方法，并对其实现方法、技术特点、效益潜力和应用前景进行了详细的阐述。     

数值气象预报中的并行计算研究

介绍了并行计算机与数值气象预报的发展概况,论述了并行算法的一般设计方法,展示了作者在数值气象预报的典型并行算法和并行实现技术方面所做的主要研究工作,以及这些研究成果所取得的一系列数值气象预报系统的并行计算结果,最后讨论了并行计算与数值气象预报的未来发展。     

一种应用于多仿生机器鱼协作的图像并行处理方法

并行处理是提高图像处理速度的重要途径。结合图像处理算子的隐合并行性和机器的字长特性,提出了一种通用的并行识别方法,利用MMX指令和SSE指令予以实现,并应用于多仿生机器鱼协作系统的视觉子系统中。该方法适于批量数据块处理,可以成倍提高系统的处理速度。     

Parallel Finite Element Method and Time Stepping Control for Non-Isothermal Poro-Elastic Problems

This work focuses on parallel finite element simulation of thermal hydraulic and mechanical (THM) coupled processes in porous media, which is a common phenomenon in geological applications such as nuclear waste repository and CO2 storage facilities. The Galerkin finite element method is applied to solve the derived partial differential equations. To deal with the coupling terms among the equations, the momentum equation is solved individually in a monolithic manner, and moreover their solving processes are incorporated into the solving processes of nonisothermal hydraulic equation and heat transport equation in a staggered manner. The computation task arising from the present method is intensive if the method is applied to model a real geological application. Therefore, we present a parallel finite element method and a time stepping method with PI (proportional and integral feedback) automatic control to improve the computation efficiency. For parallel computing, the domain decomposition method is unitized to partition both computation tasks of the equation assembly and the linear solve, and the establishment of a global system of equations is thoroughly avoided. Moreover, an object-oriented concept of sparse matrix and iterative linear solver for large scale parallel and sequential simulation is developed. By simulating a real application with THM coupled processes, we show that the present parallel finite element method works fine for both monolithic and staggered scheme within coupling iterations, and furthermore we show the efficiency of the present method by the speedup we have achieved in the simulation.