普适计算中基于移动代理的应用follow me迁移技术*

为了更好地利用普适计算环境中的计算资源、减少人为干预、提高工作效率,提出了应用的follow-me迁移需求,即计算可以随着用户的移动在异构设备和计算环境中移动,让移动中的用户能够体验到不间断的计算。提出了基于移动代理的普适计算中间件FollowMeAgent。结合情境感知技术,利用软件代理所具备的移动性实现应用的自主迁移,并根据应用特点对迁移策略进行了细分。在此平台上开发了若干应用,通过性能测试证明其可行性和有效性。     

普适计算中基于移动代理的应用follow—me迁移技术

为了更好地利用普适计算环境中的计算资源、减少人为干预、提高工作效率,提出了应用的follow-me迁移需求,即计算可以随着用户的移动在异构设备和计算环境中移动,让移动中的用户能够体验到不间断的计算。提出了基于移动代理的普适计算中间件FollowMeAgent。结合情境感知技术,利用软件代理所具备的移动性实现应用的自主迁移,并根据应用特点对迁移策略进行了细分。在此平台上开发了若干应用,通过性能测试证明其可行性和有效性。     

基于软件代理的学习资源检索技术研究与应用

学习资源检索是网络教育资源服务的重要内容,传统搜索门户式的资源检索方式在资源的个性化服务能力、自主检索能力等方面有所欠缺.软件代理技术为实现学习资源的分布式检索、个性化服务等功能上提供了便利的途径,使实现学习资源的自主服务成为可能.利用软件代理的自主性、协作性和移动代理的迁移性特点,提出了一种基于软件代理的学习资源检索策略,研究了采用代理通信语言实现代理问通信,将检索操作指令嵌入在通信原语中,实现多代理通信与代理迁移机制相配合的分布式网上学习资源检索机制,并在此基础上实现了一个应用原型系统.     

普适环境下基于中间件的身份验证模型*

为了更好地保证普适计算环境中计算资源的安全性,减少人为的非正常破坏,提出了普适环境下应用的身份验证需求,即验证不仅要随时随地,而且可以随着用户的移动在异构设备和计算环境中移动,让移动中的用户能够体验到不间断的计算。提出了基于移动代理的普适计算中间件ValidateAgent,并结合情境感知技术, 给出了验证模型、算法及原理。此研究对于普适计算在协同设计领域中的应用有重要意义。     

基于移动Agent的P2P资源发现模型PIMA

基于移动代理的P2P资源搜索方法是P2P搜索研究中较为新颖的方法.提出一种新的基于移动代理的P2P模型PIMA.并在此模型基础上提出相应的资源搜索算法.该模型集成节点集群技术和蚂蚁优化算法.以在Agent迁移中实现进一步的性能提高.     

移动代理恶意主机问题研究综述

1 引言移动代理技术在1994年一经提出,因其开放性、灵活性、健壮性、扩缩性、经济性和支持移动客户等特点,作为一个提供网络服务开发和个性化的统一框架,作为一种分布计算和移动计算的支撑技术.得到广泛的研究。移动代理在远程实时控制、移动客户支持、信息查询、电子商务、网络管理和控制、远程信息处理、个性化网络服务、分布科学计算等方面都有很好的应用背景。学术界和工业界对移动代理都呈现出浓厚的兴趣,纷纷进行研究。国际上至今已涌现出70多个移动代理系统。但是我们也要看到,移动代理作为一种非常灵活的新型计算模型,存在一些亟待解决的问题,如:移动代理安全问题、强迁移问题、移动代理的exact-ly once容错问题,等。     

移动计算环境下支持移动节点迁移的故障检测算法

与有线的固定环境相比,移动环境中的无线网络连接更加脆弱,移动主机可靠性更差,为提高移动计算系统的容错性能,研究并提出一个移动计算环境下支持移动节点迁移的故障检测算法.在基于互测比较和概率诊断的区内故障感知算法基础上,针对移动节点自由迁移导致的区内故障感知算法中移动主机(MH)漏检或故障恢复不彻底问题,引入条件检查和故障信息发布机制,提出支持移动节点迁移的移动计算环境下的故障检测算法.仿真实验表明:算法满足故障检测要求,能够适应动态的移动计算网络环境.     

弹性移动云计算的研究进展与安全性分析

弹性移动云计算(elastic mobile cloud computing,EMCC)中,移动设备按照实时需求将部分任务迁移到云端执行,无缝透明的利用云资源增强自身功能.将现有EMCC方案分为雇佣云端完成部分计算密集任务的计算迁移型移动云计算(computing migration-mobile cloud computing,CM-MCC)和通过云端的虚拟移动设备来辅助或代替移动设备完成多种任务的云端代理型移动云计算(cloud agentmobile cloud computing,CA-MCC)两类,分别对CM-MCC,CA-MCC的适用场景、实现流程、关键技术、存在问题及相应解决方法进行研究并指出其发展方向.对EMCC所面临的主要安全威胁,包括用户的错误操作或恶意行为、恶意代码、通信安全以及虚拟系统漏洞、多租户、不安全资源等云安全问题进行分析并研究相应防御方法,指出安全问题将是EMCC研究的重点和难点.     

油气工程师助手（PDA）移动代理平台的研究与实现

移动计算被认为是对未来最有影响的四大技术方向之一,它使得计算机或其他信息设备在没有与固定的物理连接设备相连的情况下能够传输数据,将有用、准确、及时的信息能提供给在任何时间、任何地点需要它的任何用户.而移动代理是唯一能满足移动计算全部要求的体系框架.为了更好地支持便携式设备上Microsoft的WinCE平台的移动计算,设计了一个基于C 的支持Windows操作系统的企业用移动代理系统--WinMAS,首次提出了基于编译性语言上的新移动代理迁移机制--利用RPC的序列化和远线程插入机制.     

VPNAgent系统连接迁移机制

移动代理系统中连接的迁移机制可用来支持移动代理之间连续透明的通信。描述了一个可靠的连接迁移机制的设计与实现,它为所有在代理迁移期间传送的数据提供准确的一次性传输。在用于虚拟专用网安全机制的移动代理平台VPNAgent系统中实现了该机制,并将其命名为AgentSocket,这是一个纯中间件实现,不需要更改Java虚拟机。     

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