基于普适环境的自适应系统研究

作为新的计算模式,普适计算为应用技术界开辟了一个崭新、宽阔的研究领域.普适计算的目标是无时无处不在而又不可见,具有泛在性、便捷性和适应性的特点,对软件自适应机制提出了新的挑战.针对自适应技术用于普适计算下存在的问题,对自适应技术的体系结构展开研究,提出了一个适用于普适计算环境的自适应中间件模型.力图实现一种能够较好支持普适计算环境的软件基础架构,并通过分布仿真原型系统的实验比较说明该中间件体系结构的执行效率.对自适应系统与自适应策略进行了探讨.     

一种普适计算环境下自适应中间件

普适计算环境固有的内在复杂性对当前的基础软件提出了新的挑战,迫切需要一种具有感知和自适应能力的中间件.提出了一个由接口、框架和情境元模型组成的自适应中间件,给出了在CAR构件平台上的设计与实现.为获取构件信息和对外提供服务,接口元模型支持同步和异步接口.情境元模型在构件对象内建模情境信息,计算实体间以基于异步事件通知方式交互.框架元模型分类和管理构件,随着运行时计算环境的变化动态改变中间件的结构和行为.软件实体感知环境的变化,实体间以松耦合的方式交互,动态改变自身的结构和行为,满足普适计算环境下的动态自适应需求.     

面向普适计算环境的Android平台服务编排框架

普适计算环境下的智能移动设备是面向终端用户的服务资源聚集和编排的主要载体。普适计算环境中的服务资源具有多种不同的形态,包括基于互联网提供的Web服务、终端设备自身服务和资源(例如本地应用、自带传感器)以及所处环境中可访问的服务(例如环境传感器)。此外,不断变化的上下文环境对软件本身的自适应能力提出了新的要求,而移动设备上的服务编排受设备计算能力和资源的限制。为了解决上述问题,提出了一个面向普适计算环境的Android平台服务编排框架ASOF。通过ASOF,移动终端可在运行时获取所需业务流程的服务模板,并对该模板中的抽象服务进行服务绑定,实现轻量级的混合服务编排,使终端能够动态获得调用普适计算环境中各种类型的服务的能力。随后,基于OSGi Felix框架给出了一套ASOF的标准实现,并以一个具体案例验证其有效性。     

面向普适计算的自适应软件集成环境研究综述

在对当今主要普适计算研究项目,尤其是面向普适计算的软件集成环境原型系统进行介绍的基础上,本文对面向普适计算的软件集成环境所关注的共性问题进行了归纳分析,包括如何为应用提供自适应的软件体系结构支持、如何为应用提供普适计算环境下所需的可重用服务、如何根据普适计算环境的特点对传统中间件技术的内涵进行扩展等等,并对面向普适计算的应用需求下软件集成环境研究所面临的挑战进行了讨论。     

普适计算中间件技术

普适计算中间件通过软件基础设施重用支持上层应用的高效开发和便捷运行,是普适计算领域的研究热点。对普适计算中间件设计挑战进行了归纳,从上下文管理、中间件层自适应、面向自适应的公共服务和自适应软件体系结构支持等方面总结、阐述和分析了普适计算中间件的各项关键技术,分类介绍了主要普适计算中间件项目,给出了未来研究发展趋势。     

基于演化硬件技术的自适应传感器

未来深空探测、海洋监测等需要系统在恶劣环境条件下长期自主工作的领域对传感器的可靠性提出了更高的要求.由此提出的概念之一就是传感器应该具备自适应能力,能够在恶劣环境条件下进行自我调节,适应新的环境变化而保持功能可用.借鉴达尔文进化论思想的演化硬件(EHW)技术为解决这一问题提供了一种可行方案.探讨了基于可重构器件的EHW技术原理,给出了EHW机制应用于自适应传感器系统的一些方法和演化自适应传感器的结构形式.     

一种基于策略的软件自适应框架

普适计算成为一种新的应用模式,普适计算运行环境的复杂性对软件自适应提出了新的挑战.提出一种基于策略的软件自适应框架,该框架采用基于上下文的自适应策略模型及上下文驱动的事件机制实现软件运行的自适应能力,该框架屏蔽了软件运行环境的复杂性,具有较强的可扩展性.     

面向网构软件的构件自适应机制研究*

结合软件agent技术,从构件角度出发,通过对传统构件进行包装,加入行为规则驱动和行为推导两大机制,提出了一种能够在运行时实时适应用户需求变化和运行环境变化的自适应构件。在自适应构件的运行和支撑方面,实现了一个可动态定制自适应构件行为规则的工具,改进了现有的构件支撑平台使得能满足自适应构件的运行需求;最后通过一个例子说明了自适应构件的设计、实现、运行和演化等一系列工作流程。初步实践表明,上述机制和整套框架为开发具有自适应性的网构软件提供了有效支持。     

基于验证的自适应系统决策:一种模型驱动的方法

自适应系统需要根据运行时上下文和自身的变化进行其行为的调节.为实现自主调节,自适应系统必须被赋予运行时监测上下文和自身变化,分析需求满足程度的变化,以及推理得到自适应决策的能力.这种在线决策的行为在满足功能需求的同时,还需要保证系统满足特定的非功能需求,如可靠性和性能等.本文提出了一种基于验证的自适应系统优化决策方法,以保证非功能需求的满足.该方法在识别可调节目标以建模自适应机制的同时,将系统的目标模型映射为相应的行为模型,用标签转移系统表示;以可靠性需求为例,用标记目标模型规约任务的可靠性;然后将系统行为模型和可靠性规约整合为带可变状态的离散时间马尔可夫链,将候选自适应配置描述为不同可变状态间的组合;最终通过相关需求的在线验证,使系统找到关于某类上下文的最优决策配置.本文通过一个移动信息系统的案例展示了该方法的可行性和有效性.     

普适计算环境下的虚拟机技术研究

普适计算环境中资源和服务利用率较低,传统应用程序在该环境下无法兼容。为此,提出一种适用于普适计算环境的虚拟机技术。使用设备请求代理屏蔽复杂的普适计算网络环境,对上层应用提供统一硬件平台,支持多个普适计算应用同时运行。实验结果表明,该虚拟化技术能兼容传统应用,提高普适计算资源和服务的利用率。     

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