并行环境下基于多处理机任务的调度模型与调度算法

1 引言目前所研究的并行系统中的任务调度问题,大都针对于单处理机任务进行。所谓单处理机任务就是指所有被调度的任务都只需要一个处理机,而且可以是任意一个处理机。然而,在网络环境下,由于各个处理机的性能和功能不尽相同,一个任务往往需要一个或多个处理机同时执行才能完成,称这样的任务为多处理机任务。如果一个任务需要r个处理机同时执行,我们就称这个任务为r-处理机任务。这里所说的“处理机”实际上是一个广义的概念,它可以是计算机系统中的CPU、内存、驱动器或打印机等,也可以是网络系统的节点、链路和带宽等。一个并行工程,无论是上层的作业,还是底层的进程,它们都需要拥有不同的各种资源组合。并行系统中多处理机任务的调度,就是充分合理地利用所有可利用的资源,依照某种顺序串行或并行地调度所有待处理的多处理机任务,使得系统的总执行时间尽可能小。     

一种同构多处理机动态实时调度算法

本文提出一种新型线性复杂度多处理机实时任务启发式调度算法,利用并行技术为动态实时系统提供较优解．使用大量存在可行调度的任务集合测试多处理机实时任务调度算法的性能,分析了几种主要参数对调度成功率的影响．实验表明新调度算法调度成功率较高,适用于不完全知晓任务参数的动态多处理机实时系统．     

具有优先链约束的网格作业多资源调度问题

网格计算是网络并行计算的发展新趋势,网格系统中的分布式资源管理和调度一直是研究的热点和难点。对于网格应用作业的多资源调度问题,一个网格作业往往要分成多步骤进行,每个步骤都需要占用多个资源。首先将该问题抽象为典型的多处理机任务调度模型P_m|fix,p=1,chain|C_max,即在m个处理机系统中调度n个多处理机任务,每个任务指派到所需一组处理机上不可剥夺地执行,而且每个任务都需要一个单位的处理时间,并根据优先关系形成链约束。该问题被证明为NP难问题。利用宽度优先技术和首次满足方法,构建了几个多项式时间近似算法,并通过模拟实验分析算法性能,实验结果显示算法是实用的。     

网络并行计算中多处理机任务调度问题研究

在网络并行计算系统中,具有多处理机任务需求的多步骤调度是一类常见问题,为此提出一种混合了多处理机任务调度（Multiprocessor Task Scheduling,MTS）和作业车间调度（Job-shop Scheduling Problem,JSP）的调度模型,即多处理机任务作业车间调度（Multiprocessor Task Job-shop Scheduling Problem,MTJSP）。与传统MTS不同的是MTJSP的每项任务的完成都要经历多个步骤。首先对[m]台处理机加工[n]项任务的MTJSP调度问题建立数学模型,然后设计了一种混合粒子群优化（Hybrid Particle Swarm Optimization,HPSO）算法进行求解。算法的改进工作包括：设计出针对多处理机问题的解码策略;采用新的粒子更新方式;增加记忆库功能,以保证全局最优解的多样性;加入基于模拟退火的局部搜索功能。大量的仿真实验验证HPSO的性能,结果显示HPSO不但能够有效解决MTJSP问题,在求解经典JSP问题中也表现优良。     

端到端时间约束的实时任务动态调度算法

在单处理机系统中,由于计算高优先级任务抢占的时间相对比较简单,所以单处理机调度理论取得了长足的进步.提出一个端到端时间约束的实时任务调度算法,当实时任务到达系统时,算法为任务的每个子任务在相应的处理机上预约一定的计算资源,把端到端的多处理机调度问题转换成单处理机调度问题,从而可以利用单处理机调度理论判定实时任务的可调度性.实验表明,该算法明显地提高了CPU利用率和任务接收率.     

网络并行计算系统中基于多处理机任务的资源调度模型

简要描述了网络并行计算系统中任务调度问题和经典的多处理机任务调度研究现状,并将两者结合到一起建立网络并行计算系统中的新型调度模型,较详细地论述了多处理机任务的定义,然后还讨论了该模型求解的近似调度策略及其近似优化问题,给出了其特例Pm｜fix｜Cmax问题的最优调度的时间跨度下界。     

P_4|fix|C_(max)问题的最优规则调度算法

多处理机任务调度问题P4|fix|Cmax(m≥=)是典型的强NP难问题,由于其在并行环境中的实际意义而受到越来越多的关注.但在一般情形下,寻求该问题的较为理想的近似算法是极其困难的,通常从较少处理机数的系统着手研究.对于m=4的情形,文中研究了P4|fix|Cmax的规则调度算法,通过引入组调度技术,给出了该问题的一个线性时间的4/3-近似算法,并证明了该算法是4-处理机系统中的最优规则调度算法.     

起始时间不同的多处理机任务调度

本文讨论起始时间不同的多处理机任务调度问题。首先提出处理机有效函数、处理机有效时间的定义，证明了一个任务在某一时刻可调度的必要条件，利用任务可调度的必要条件设计ＥＴＥＰＦ算法，并通过仿真分析，说明算法的性能。     

非安全互连同构系统上的静态任务调度

在分布式内存多处理机ＤＭＭ（ｄｉｓｔｒｉｂｕｔｅｄ ｍｅｍｏｒｙ ｍｕｌｔｉｐｒｏｃｅｓｓｏｒ）系统中,不同处理机上运行的任务之间的通信开销仍然很大,有时甚至抵消了多处理机并行所带来的好处．为了使并行程序在ＤＭＭ系统上能得以高效的执行,必须采用合理的调度技术将任务分配给处理机．章首先分别给出了任务调度系统中的任务模型、处理机模型以及调度问题的形式化描述,然后在此基础上研究了任务调度中３个最重要的     

非完全互连同构系统上的静态任务调度

在分布式内存多处理机DMM(distributed memory multiprocessor)系统中,不同处理机上运行的任务之间的通信开销仍然很大,有时甚至抵消了多处理机并行所带来的好处.为了使并行程序在DMM系统上能得以高效的执行,必须采用合理的调度技术将任务分配给处理机.文章首先分别给出了任务调度系统中的任务模型、处理机模型以及调度问题的形式化描述,然后在此基础上研究了任务调度中3个最重要的问题,即(1) 如何顺序选择参与调度的任务,(2) 如何选择路由,(3) 如何分配任务给处理机.其中,路由选择     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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