电子商务平台认证中心的研究与设计

CA认证系统是PKI的核心组成部分,它负责为PKI中的实体颁发公钥证书。公钥证书是将实体的身份和公开密钥绑定在一起的一种数据结构,数字证书是整个PKI的核心技术,管理证书的证书系统就成为PKI的核心部分。     

一种基于消息中间件的PKI系统应用集成方案

针对分布式环境下为大规模的证书用户提供及时、多样的证书服务所产生的对PKI系统中各实体的组织与管理等问题,提出一种PKI系统的应用集成方案.该方案以AMQP消息中间件作为集成方式,运用面向服务思想对各实体进行管理,采用异步的发布/订阅方式实现消息的传输,能够为PKI系统提供一个高效、稳定、且扩展性强的集成与通信平台.通过实验表明该应用集成方案能够在不对PKI系统性能造成较大的影响下,提高PKI系统在处理大规模证书服务时的整体性能.     

基于位置信息的可扩展PKI模型

在移动通信系统中引入公钥基础设施PKI(Public key infrastructure)所要面临的挑战之一是:如何有效地在不同的地区PKI之间建立证书链(置信关系),同时保持区域自治性.基于位置信息的可扩展PKI模型改进了传统模型在上述方面的性能.     

PKI与PMI联合安全认证系统及其设计

文章在研究X．509 V3所定义的公钥证书和属性证书的基础上,分析了PKI和PMI的系统组织结构，设计了一个PKI和PMI联合安全认证系统，给出了证书存储与管理目录服务器的配置与管理程序设计，系统使用公钥证书进行身份认证，使用属性证书进行角色控制，可以方便灵活地实现网络资源的安全访问控制。     

基于PKI的安全系统及其基于XML技术改进的研究

公钥基础设施PKI是现代网络信息安全领域中的一门新兴主流安全技术。该文分析了基于PKIS规范设计实现的一个PKI安全系统,给出了系统架构和工作流程细节,剖析了系统的局限性。随后介绍了近年新出现的XML安全规范与技术:XML-ENC、XML-SIG、XKMS,基于异构互操作XML安全技术,给出了一个改进的PKI安全系统,即通过增加一个Web服务-可信任服务中间层来分离客户端密钥管理负载,并屏蔽底层异构PKI的复杂性,详细论述了改进新安全系统的优越特性。     

基于OCSP协议的证书状态查询系统

证书状态查询是PKI系统中的一个关键问题,OCSP是解决这个问题的一种重要机制。本文分析并改进了OCSP协议,并在此基础上设计了一种高效的证书状态查询系统。文中对该系统的重要组成部分以及关键技术进行了详细的论述。     

采用PKI增强VPN安全的研究

VPN技术改进了通信协议的安全机制，但因其身份鉴别不完善而影响到在复杂环境下的网络安全。PKI是由公开密钥密码技术、数字证书、证书认证机构和安全策略等基本成分共同组成的安全基础设施。PKI技术能够提供身份鉴别和角色控制服务。文章分析了PKI和VPN技术的各自安全特点，采用PKI技术与VPN技术相结合的方法，增强了系统的身份鉴别和访问控制能力。     

证书撤销机制的分析与设计*

证书撤销管理是大规模公钥基础设施PKI中十分重要且耗费最多的操作。分析了在PKI实施中应用的证书撤销机制,比较了证书撤销列表CRL、增量CRL、分段CRL与重复颁发CRL在峰值请求大小、网络带宽影响、用户查询代价等方面的性能,指出了各种机制的优缺点,最后对不同PKI规模中的证书撤销系统进行了设计和性能分析。     

PKI证书链的分布式存储与应用

为进一步简化PKI互操作,本文设计了一种称为证书链接表的数据结构,将PKI证书链的构成信息分布存储在各个CA节点。证书链的分布式存储可应用于证书撤销信息的发布与查询、PKI互操作、证书路径构造等方面。     

NPKI-基于嵌套证书的PKI系统

NPKI，即基于嵌套证书的PKI系统，在不改变原有PKI层次结构和信任关系的前提下，优化了证书的证明路径，提高了各级CA的效率，从而有效地弥补了PKI在证书有效性证明中存在的不足。     

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