基于Netware的FoxPro数据库完整性约束的实现

分析了数据库完整性原理及其一般实现方法 ,提出采用事务跟踪系统 TTS(Transaction Tracking System)来解决基于 Netware的 Fox Pro数据库数据完整性问题 ,并给出应用实例。     

Web服务组合事务处理研究与实现

通过重用已有的服务进行服务组合来实现应用集成;而保证服务组合的事务特性是实现服务组合的关键。文中提出一个Web服务组合事务处理模型,将BPEL (Business Process Execution Language,业务流程执行语言)的流程设计与WS-C/T (Web Services Coordination/Transaction,Web服务协调/事务)规范结合。该模型主要由客户端、BPEL执行引擎、事务协调器和参与者四个部分组成。客户端发起请求,BPEL执行引擎响应请求并开启事务,事务协调器和参与者根据事务协调算法完成事务协调。     

基于替代和补偿的嵌套Web Service事务模型

作为一种崭新的并行计算模式,Web Service以其平台独立性、松耦合及自治性等优势,在涉及复杂业务流程的事务性服务行业具有极大潜力和需求.考虑到Web Service环境的限制和特征,传统事务模型无法适应.从Web Service事务系统体系结构出发,分析Web Service的特点及Web Service事务性应用在开放的Web环境下的特性,提出了一个基于替代和补偿的嵌套Web Service事务模型,阐述了结合替代和补偿的Web Service事务结构和处理,给出了形式化描述.     

基于时间戳的并行实时事务调度策略

传统并行事务处理方法不适用于实时数据库，对几种相关事务调度策略进行比较，提出一种基于时间戳的并行实时事务调度策略TS-PRTTS(Timestamp based Parallel Real-Time Transaction Scheduling)，采用M／G／1队列模型，利用时间戳控制子事务同步．实验证明，该策略能较好协调同步控制与通信代价矛盾，在系统负荷较重以及数据倾斜、访问倾斜问题较突出时具有良好的性能。     

基于BPEL和ws-Tx的Web服务组合事务协调框架研究

针对当前Web服务事务协调框架中缺乏对服务组合流程定义的支持而需要在协调过程中手动定义业务流程的问题,提出了一种支持流程和事务语义自动抽取的服务组合事务协调框架。该框架从扩展了事务语义的业务流程执行语言(Business Process Execution Language,BPEL)中抽取协调信息,并结合Web服务事务规范(Web Services Transaction,WS-TX)所定义的协调器实现了服务组合的全局事务协调。通过将WS-TX在事务协调和BPEL在业务流程设计方面的优势相结合,该框架将业务逻辑与事务处理逻辑有效地分离。最后通过实例分析说明了该框架的可行性。     

具有原子中断机能的数据备份系统

针对数据库系统的备份,提出了事务组（Transaction Group,TG）的概念。在传统数据备份系统的基础上实现了以组为单位的数据备份和恢复功能,并且保证了组操作的原子性,最后论述了TG的设计和实现细节。     

一个基于共享内存的企业级Web服务事务处理模型研究

Web服务事务处理必须提供协调短事务和长事务的能力。本文提出了一个基于共享内存的Web服务事务处理模型，在以．Net为开发工具实现企业级信息管理系统时，利用现有技术，不对Web Service进行任何扩展，在Web Serice中处理原子事务和内聚事务。     

Web service的事务协调框架研究与实现

提出并实现了一种Web服务的事务协调框架,DTCF（Distributed Transaction Coordination Framework）。该模型基于嵌套事务模型和协调思想,将局部事务的实现细节进行封装,不同局部事务可采用不同的并发控制和恢复技术,而对全局事务则采用完全分布的管理机制进行管理。DTCF是一种可重用的框架,实验结果表明其可用性。     

Web服务组合事务处理研究与实现

通过重用已有的服务进行服务组合来实现应用集成;而保证服务组合的事务特性是实现服务组合的关键。文中提出一个Web服务组合事务处理模型,将BPEL（Business Process Execution Language,业务流程执行语言）的流程设计与WS—C／T（Web Services Coordination/Transaction, Web服务协调／事务）规范结合。该模型主要由客户端、BPEL执行引擎、事务协调器和参与者四个部分组成。客户端发起请求,BPEL执行引擎响应请求并开启事务,事务协调器和参与者根据事务协调算法完成事务协调。     

微服务架构下的分布式事务处理

单体架构下的分布式事务是一个服务内访问多个数据源的分布式事务,可以采用传统分布式事务处理模型——DTP(Distributed Transaction Processing)模型来解决。在微服务的架构下,可能会出现跨服务、跨资源的分布式事务。在解决这类分布式事务时,微服务追求系统的可用性和最终一致性而非数据的强一致性。针对不同的微服务分布式事务场景,介绍不同的分布式事务处理模型,包括可靠消息模型、业务补偿模型和TCC(TryConfirm/Cancel)模型,并总结每种模型的处理流程和优缺点。对TCC模型在性能上和可移植性上提出优化方案。     

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.     

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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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