一种面向服务网格的通用框架及服务访问模型

网格资源的表示、组织、部署、发现、创建、使用和撤销是网格计算的重要研究问题,随着Webservices技术和服务网格理念的逐步成熟,以“服务”的方式来包装网格资源已经成为了一种趋势,并得到了网格界的一致认同。由于网格资源的“充足性”及“共享性”,采用池的方式来组织网格资源,以及把网格资源包装成服务,是一种很合理的方式。用户对网格的一次访问过程包括访问场景的创建,访问的实施,以及实施完成后的撤销,具有生命期的特征,而这正是虚拟组织所具有的功能,基于虚拟组织来设计服务访问模型是很合理的。基于物理资源池、服务池以及虚拟组织的思想,文章提出了面向服务网格的通用框架模型及服务访问模型VSP,VSP模型被用于指导HowU信息处理平台的设计。     

一种有盟主的服务虚拟组织模型及其在电子政务中的应用

提出了一种有盟主的服务虚拟组织模型（SHALOM），旨在服务网格环境下针对盟主的目标需求，解决盟主如何动态组织自主的合作伙伴的服务和流程资源构建虚拟组织协同进行求解的问题．在该模型的支撑下，盟主在业务层定义目标需求和分解任务，通过虚拟组织需求和成员提供的服务之间的匹配，动态选取相关合作伙伴的服务和流程资源．盟主在虚拟组织中的流程和服务资源之间定义协作关系，并采用聚合机制即时生成可运行的虚拟组织．文中重点讨论了SHALOM模型的核心元素和运作原理，并相应地介绍了支撑框架和相关技术，最后结合实际低成本电子政务应用展示了模型的效果．     

基于OGSA的网格虚拟组织建立

OGSA是新型的网格体系结构，它支持虚拟组织中服务的创建、保持和应用。本文讨论了基于OGSA的虚拟组织合作伙伴选择以及虚拟组织建立的一般过程，给出了在一种网格环境下构建虚拟组织的方法。     

网格服务复制机制的研究

网格的OGSA模型要求网格上一切资源都是服务,实现对网格服务的复制可以解决网格中网格服务的访问瓶颈、负载均衡等问题.现有的网格副本服务技术只能对数据、文件资源等静态资源进行复制,不能对包含软硬件需求的有状态的网格服务进行复制.针对这一问题,我们提出了一种有状态网格服务的复制方法,该方法基于虚拟工作空间、Snapshot和有状态资源模拟技术的原理,实现了对网格服务代码的复制、对网格服务运行所需的软硬件环境的复制和搭建、对网格服务内存数据的复制和对网格服务使用的有状态资源的复制.     

基于虚拟组织的访问控制模型

网格体系结构中最重要的是中间层——虚拟资源层,该文提出一种改进的基于虚拟组织的网格体系结构,通过对虚拟组织进行抽象、规划及相应的映射,使网格资源具有易查找和易管理的特点,在映射资源的同时映射该资源的访问控制权限,由资源的拥有者界定资源的安全策略,从而增强网格系统的安全性。分析和给出了该模型的安全性和访问控制过程。     

Globus网格体系结构及其服务的实现

阐述了网格计算、虚拟组织的概念，对Glohus网格体系结构(构造层、连接层、资源层、汇集层和应用层)进行了剖析，并提出了网格服务实现的简单构想。     

基于Gossip协议的网格资源发现机制

由于网格环境中存在着大量分布、异构、动态的资源和服务,快速、准确地进行资源发现,是关系到网格计算性能的关键因素之一。该文按照虚拟组织(V irtual Organization)——机构(Institution)——资源(Resource)的层次,建立分层网格模型,提出了该模型上的资源发现机制,包括信息共享、消息扩散及资源查询机制。通过模拟实验,表明了该资源发现机制的查询应答率较高,同时消息扩散的开销较小。     

支持虚拟组织建立的网格资源协作平台研究

针对基于Internet的学习平台在有效利用教学资源方面存在的问题,采用开放网格服务架构OGSA,建立基于虚拟组织的协作平台.在虚拟组织中,应用或用户能够创建临时服务,资源以网格服务的形式提供给用户或应用.基于OGSA的虚拟组织的建立,为资源共享协作提供了切实可行的解决思路和实施方案.     

网格环境下基于虚拟组织的调度模型

虚拟组织是指在个人、机构或团体间一种灵活、安全、平等的资源共享动态集合,这种共享更强调直接对计算机、软件、数据以及其它资源的直接访问.管理虚拟组织资源、协同工作来解决大规模的计算是一个复杂的问题.提出了一个基于虚拟组织的资源分配和任务调度模型,为资源的管理和应用程序的调度建模网格服务提供者向虚拟组织注册,并发布它能够提供的服务,任务调度器根据提供者属性分解任务并采用特定的算法将任务分配给不同的服务提供者.这个框架的模型侧重研究如何调度任务,根据任务的属性合理分配资源来解决复杂计算问题.     

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.     

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.     

法律信息库系统

本文分析了法律数据库的结构和特点，介绍了采用面向对象设计方法和超文本数据库技术开发和实现法律信息库系统将作为重要网络资源之一为不同用户进行法律咨询服务。     

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.     

International Journal of Automation and Computing Table of Contents

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Information for authors

正SCIENCE CHINA Information Sciences(Sci China Inf Sci),cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China,and published by Science China Press,is committed to publishing highquality,original results of both basic and applied research in all areas of information sciences,including computer science and technology;systems science,control science and engineering(published in Issues with odd numbers);information and communication engineering;electronic science and technology(published in Issues with even numbers).Sci China Inf Sci is published monthly in both print and electronic forms.It is indexed by Academic OneFile,Astrophysics Data System(ADS),CSA,Cabells,Current Contents/Engineering,Computing and Technology,DBLP,Digital Mathematics Registry,Earthquake Engineering Abstracts,Engineering Index,Engineered Materials Abstracts,Gale,Google,INSPEC,Journal Citation Reports/Science Edition,Mathematical Reviews,OCLC,ProQuest,SCOPUS,Science Citation Index Expanded,Summon by Serial Solutions,VINITI,Zentralblatt MATH.     

Erratum to: Fast global kernel fuzzy c-means clustering algorithm for consonant/vowel segmentation of speech signal

正Erratum to:J Zhejiang Univ-Sci C(ComputElectron)2014 15(7):551-563doi:10.1631/jzus.C1300320The original version of this article unfortunately contained mistakes.Algorithm 6 should be as follows:Algorithm 6 FGKFCM-F clustering Input:(1)X={x_1,x_2,…,x_N},,x_iR~d,i=1,2,…,N,the dataset;(2)C,1C≤N,the number of clusters;(3)ε0,the stopping criterion;     

Journal of Zhejiang University-SCIENCE C (Computers & Electronics) Total contents

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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.