支持NAT穿越的IKE协商

NAT设备改变经过它的数据包的IP地址,这导致和IPSec协议不兼容.IPSec协议和NAT之间的不兼容性严重阻碍了IPSec在实际中的应用.IKE协议是IPSec的重要组成部分,用于实现IPSec参数的自动管理,文中从实现的角度论述了在IKE协商过程中如何实现NAT穿越的功能.     

校园网实现IPSec穿越NAT的解决方案

介绍了IPSec协议和NAT的工作原理。分析了IPSec和NAT不兼容的的原因。提出了一种使用UDP数据封装和IKE修改相结合的方法实现IPSec穿越NAT的设计方案,并给出了该方案的设计思想,     

基于代理机制改进UDP封装方式实现VPN穿越NAT

NAT设备需要改变数据包的IP地址和端口号，而端口号等信息在IPSec协议中是经过加密的，这导致了NAT和IPSec协议的不兼容性。介绍了采用UDP封装方式实现VPN穿越NAT的方法，以及采用代理机制对其改进，并通过实例对改进的方法优缺点进行了分析，使其能解决IKE协商的响应者在NAT设备后的问题。     

VPN网络中IPSec穿越NAT的研究

首先介绍了NAT和IPSec协议的基本原理,并详细分析了两者的不兼容性.针对原有UDP封装草案的不足之处进行了改进,并详细描述了使用改进方案完成NAT穿透的具体实现,考虑到安全性,对IKE协商实现过程也作了些改进.最后对改进后的方案进行了可行性分析.     

基于IKE的IPSec参数协商过程的研究

在IPSec协议实现过程中，利用IKE协议可以实现IPSec参数的自动管理，技术上 存在着很大优越性。该文从IKE协议实现的角度，简要说明了IKE守护进程的工作原理，重点 分析了IKE协议的消息协商过程。     

基于IPSec的VPN密钥交换（IKE）协议的分析与实现

在研究IKE协议的基础上，首先分析了IKE的安全性并讨论了防范措施，继而分析了IPSec安全网关基本模型以及包括IKE模块在内的各模块之间的关系，提出了在IP协议栈上集成IPSec协议的方法，并对IKE在IPSec安全网关上实现的问题进行了描述。     

IPSec协议与网络地址转换的融合

私有地址的广泛应用促使有必要研究IPSec协议和NAT的结合。IPSec协议提供安全服务决定其与NAT融合具有特殊性，在综合分析IPSec和NAT共处的矛盾及比较现有的解决方案的基础上，提出了基于隧道技术，利用NAT网关实现IPSec与NAT的共处，提供了一种IPSec协议在私有地址域的可行性实现。     

NAT与IPSec协议兼容性问题及解决方案

概要介绍了IPSec协议和网络地址转换(NAT)协议的基本原理，着重介绍了IPSec协议与NAT协议所存在的矛盾，最后介绍了采用UDP封装方式实现IPSec报文穿越NAT的完整方案。     

IPSec的NAT穿越方法的改进研究

提出了一种改进的方法,用以解决IPSec和NAT的冲突问题。该方法引入了标识域和会话域。IPSec接收端通过会话域中载荷的TAG_VALUE的后6个字节来识别源IP地址和端口信息,通过标识域识别IKE报文和IPSec报文。报文对NAT是透明的。实验证明该方法能很好地解决在传输模式下多用户接入的问题而且方便实现。     

应用Kerberos的虚拟专用网研究与实现

介绍了实现VPN的网络层协议技术－IPSec技术，分析IPSec协议中的IKE协议，针对IKE协议中存在的不足，提出了应用Kerberos的VPN方案，并详细介绍了方案的系统拓扑结构、系统逻辑结构，系统工作流程和系统模块划分。     

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.     

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.     

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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