基于动态数据联盟的虚拟设计/制造系统—VC~3

提出了一种基于因特网络的快速市场反应虚拟设计／制造系统的体系结构－ＶＣ３。该系统以数据仓库为核心，以专业专家系统为各个生产环节的决策系统，以网络环境的专业竞争为优化机制，实现了网络环境的、面向市场反应的新一代 ＣＡＤ系统集成。     

基于Internet的虚拟网络校园系统

本文根据Internet网络服务的时空跨越特性,设计并实现了一个以Internet网络技术为基础和环境的虚拟网络中学校园系统框架(FVMS)。以虚拟网络中学校园系统框架为基础建立的网络校园教育系统不仅能够克服传统中学教学资源在时间和空间分布适应上的局限性,而且在网络教学方式和教学协作方面比传统的远程网络教育系统有着更好的针对性和灵活性。     

网络环境下动态联盟管理系统体系结构的研究

介绍了动态联盟的基本概念及其与传统企业组织方式相比的优势,探讨了一种在网络环境下动态联盟管理系统的体系结构。首先,介绍了系统体系结构组建的总体思想;其次,介绍了网络环境下动态联盟管理系统的总体功能结构,及其重要模块的功能;然后,介绍了在网络环境下系统的实现结构及其结构的特点;最后,以三花企业为背蒂,介绍了网络环境下该动态联盟管理系统体系结构的实际应用及所取得的成效。     

基于DynamipsGUI的虚拟网络实验环境构建

本文主要针对于当前高职院校中计算机网络课程教学中实验环境构建的问题提出了一种解决方案,即利用虚拟机软件Dy-namipsGUI和VMWARE在单机上构建虚拟网络实验环境,并以一个实例介绍DynamipsGUI和VMWARE的配置连接问题。实践证明,虚拟网络实验环境可以将通用机房转换为专业的网络实验室,有效提高学生网络设备配置操作的实践技能。     

基于DynamipsGUI的虚拟网络实验环境构建

本文主要针对于当前高职院校中计算机网络课程教学中实验环境构建的问题提出了一种解决方案,即利用虚拟机软件Dy-namipsGUI和VMWARE在单机上构建虚拟网络实验环境,并以一个实例介绍DynamipsGUI和VMWARE的配置连接问题。实践证明,虚拟网络实验环境可以将通用机房转换为专业的网络实验室,有效提高学生网络设备配置操作的实践技能。     

基于RT-TCP/IP的虚拟试验通信平台研究

网络是虚拟试验系统环境的重要组成部分.以某军工虚拟试验系统为背景,基于RT-TCP/IP和虚拟共享内存机制实现了虚拟试验通信平台.分析了RTX实时操作子系统和RT-TCP/IP的实时性能,论证了使用RT-TCP/IP协议构建虚拟试验局域网的可行性;设计并实现了实时以太网虚拟共享内存中间件(RTEVSM).在RTX环境下对RTEVSM中间件的数据传输延迟、抖动性等性能指标进行了测试,与在Windows-NT环境下性能指标进行对比,验证了系统在RTX环境下具有较强的实时性和传输可靠性.应用结果表明,本方案对实时性要求高的分布虚拟试验系统搭建具有一定的实用价值.     

中职学校计算机网络综合实训室建设

培养具有较强职业岗位技能的人才是中职网络技术专业的培养目标,要实现这个培养目标,需要建立一个专业的网络实训室。本文以贵州省商业学校的网络实训室建设为例,对中职学校计算机网络综合实训室建设进行探讨。     

中职学校计算机网络综合实训室建设

培养具有较强职业岗位技能的人才是中职网络技术专业的培养目标,要实现这个培养目标,需要建立一个专业的网络实训室。本文以贵州省商业学校的网络实训室建设为例,对中职学校计算机网络综合实训室建设进行探讨。     

基于XML的分布式虚拟运行环境建模与实现

当前很多网络计算环境尚缺乏为多种应用提供隔离、定制的运行环境的能力,给网络计算环境的广泛应用带来障碍.而虚拟机技术的飞速发展,使得根据用户需求,按需构建隔离、定制的分布式虚拟运行环境成为可能.基于XML schema技术对分布式虚拟运行环境进行了建模和描述,阐述了分布式虚拟运行环境的运行支撑系统(ACOPE系统)的详细设计和原型实现.该系统能够通过对宿主资源和虚拟机资源的有效管理,根据分布式虚拟运行环境的XML描述文件,在网络计算环境中选取部分宿主资源并在其上创建或克隆满足相应配置需求的虚拟机,支持分布式虚拟运行环境的动态按需构建和使用.最后通过实验验证了ACOPE系统的有效性.     

在线虚拟网络实验平台的设计与实现

本文主要针对于当前高等院校网络工程课程教学中实验环境构建的问题提出了一种解决方案,即利用Dynamips软件构建后台虚拟路由器和交换机环境,建立Web服务器实现客户端与后台的通信,构建在线虚拟网络实验平台。实践证明,在线虚拟网络实验平台可以将通用机房转换为专业的网络实验室,有效提高学生网络设备配置操作的实践技能。     

M/G/c/K blocking probability models and system performance

An exact solution for the M/G/c/K model is only possible for special cases, such as exponential service, a single server, or no waiting room at all. Instead of basing the approximation on an infinite capacity queue as is often the case, an approximation based on a closed-form expression derivable from the finite capacity exponential queue is presented. Properties of the closed-form expression along with its use in approximating the blocking probability of M/G/c/K systems are discussed. Extensive experiments are provided to test and verify the efficacy of our approximate results.     

设计模式变体的描述与验证*

为解决标准设计模式演化后难以检测的问题,引入设计模式变体思想,以Bridge模式为例,给出了八种常用的变体实现,并以人工形式挖掘了四种开源系统中Bridge模式变体的基准数,接着在Apache Ant1.6.2与JHotDraw5.1开源系统中通过六种主流设计模式检测工具进行了变体检测实验。试验结果表明,FCA-CBR方法简单有效,对2种开源系统中Bridge模式变体检测的精确率达到60%与48.1%,与先前方法相比有了较大的提高。     

(r∞, n12, s12) measurements on the 2-CPU CRAY X-MP

We report performance measurements made on the 2-CPU CRAY X-MP at ECMWF, Reading. Vector (SIMD) performance on one CPU is interpreted by the two parameters ($\text{r}{}_{\mathrm{\infty }}\text{, n}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$), and we find for dyadic operations using FORTRAN $\text{r}{}_{\mathrm{\infty }}\text{= 70}\text{Mflop/s}\text{, n}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 53}\text{flop}$. All vector triadic operations produce $\text{r}{}_{\mathrm{\infty }}\text{= 107}\text{Mflop/s}\text{, n}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 45}\text{flop}$; and a triadic operation with two vectors and one scalar gives r_∞ = 148 Mflop/s and $\text{n}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 60}\text{flop}$. MIMD performance using both CPUs on one job is interpreted with the two parameters ($\text{r}{}_{\mathrm{\infty }}\text{, s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$), where $\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ is the amount of arithmetic that could have been done during the time taken to synchronize the two CPUs. We find, for dyadic operations using the TSKSTART and TSKWAIT synchronization primitives, that r_∞ = 130 Mflop/s and $\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 5700}\text{flop}$. This means that a job must contain more than ～ 6000 floating-point operations if it is to run at more than 50% of the maximum performance when split between both CPUs by this method. Less expensive synchronization methods using LOCKS and EVENTS reduces $\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ to 4000 flop and 2000 flop respectively. A simplified form of LOCK synchronization written in CAL code further reduces $\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ to 220 flop. This is probably the minimum possible value for synchronization overhead on the CRAY X-MP.     

Geom/G/1/n system with LIFO discipline without interrupts and constrained total amount of customers

Consideration was given to the discrete-time queuing system with inversive servicing without interrupts, second-order geometrical arrivals, arbitrary (discrete) distribution of the customer length, and finite buffer. Each arriving customer has length and random volume. The total volume of the customers sojourning in the system is bounded by some value. Formulas of the stationary state probabilities and stationary distribution of the time of customer sojourn in the system were established.     

Complex random sample scheduling and its application to an N/M/F/Fmax problem

“Complex Random Sample Scheduling(CRSS)” was proposed in this paper as an efficient heuristic method for solving any permutation scheduling problems. To show the effectiveness of the proposed CRSS, it was applied to an N-job, M-machine, permutation flowshop scheduling problem to minimize makespan, N/M/F/F_max. Numerical experiments made it clear that the proposed CRSS provides a schedule very close to the near-optimal schedule obtained by the existing promising heuristic methods such as taboo search and simulated annealing, within less computation time than these heuristic methods.     

Efficient implementation of Johnson''s rule for the n/2/F/Fmax scheduling problem

Several efficient algorithms of O(n log n) computational complexity, for the Johnson's rule to schedule a set of simultaneously available jobs on two machines in a flowship to minimize the maximum job flowtime have appeared in the literature. A modified version of one of these algorithms is presented which not only simplifies the programming effort for implementation but is also able to generate all possible optimal sequences obtainable from Johnson's rule.     

On the M/Ck/1 queue

We obtain the exact analytic expression of the probability distribution of the number of units in a single server queue with Poisson arrivals and Coxian service time distribution (notated as M/C_k/1). A recursive procedure for calculating this probability distribution is given. The well-known queues M/E_k/1 and M/D/1 are re-derived as special cases of the M/C_k/1 queue. Finally, the cases of M/C₂/1 and M/C₃/1 are fully worked out.