一种Web服务QoS可信性评价模型

随着Web服务数量的增加,根据Web服务的非功能属性(QoS)度量Web服务质量成为研究热点之一.目前对Web服务QoS的研究主要集中在QoS信息管理、QoS度量方法及基于QoS驱动的服务选取上,但对于QoS评价的可信性研究较少.本文在目前QoS研究的基础上提出一个Web服务QoS可信性评价模型,并给出了两种Web服务QoS可信性评价方法.最后,描述了可信性评价的实验过程及效率分析.     

Web服务组合中QoS评分度量模型的研究

在Web服务组合过程中,QoS(quality of service)是决定其组合能否成功的关键因素之一。这篇文章在分析了Web服务组合中QoS的非功能属性基础上,分别从四个角度来描述通用的QoS属性,并对服务构件的QoS服务质量进行了量化,最后给出了开放环境下Web服务组合中QoS的评分度量模型。     

基于QoS关联的Web服务组合算法

为反映Web服务组合过程中服务类之间的关联性和客户对服务非功能属性的偏好,以及服务调用过程中不同服务质量(QoS)属性之间的内在关系,提出基于QoS关联的Web服务组合决策算法。在评价服务组合优劣程度的过程中,考虑服务类在QoS属性上的关联关系,对QoS数据进行统一规格化和综合评估。实验证明,该算法拥有较好的执行效率和稳定性,并且选择结果较优。     

QoS驱动的主体服务匹配

分析了目前主体服务匹配的研究现状和存在的问题，为了正确匹配到用户最满意的主体，提出了一个服务质量(Quality of Service,QoS）模型，该模型比较客观的反映了主体服务非功能属性的特征，并研究了该QoS模型上的各种计算和评价方法，在QoS模型的基础上，重点研究了一种QoS驱动的主体服务匹配算法，该算法克服了KSycara,K Arisha、G J Wickler和Z Zhang等人提出的主体服务匹配算法中存在的不足，最后用仿真实验验证了提出的主体服务匹配算法的有效性。     

一种轻量级的Web服务QoS预测机制

服务质量（Quality of Service, QoS）作为Web服务非功能属性的代表,已被广泛作为重要的服务选择依据。然而现有QoS预测方法存在着难以兼顾运行效率与预测准确度的问题,且普遍忽略了服务器端的QoS预测。针对该问题,提出一种适用于服务器端环境的轻量级QoS预测机制（LPM）。LPM基于卡尔曼滤波算法构建QoS状态转换模型实现来QoS预测,并借助预测准确度优化预测周期。实验结果显示,在存在显著量测噪声的应用环境中,LPM的预测准确度明显优于常规方法。LPM的QoS预测结果可为用户选择Web服务提供首要的客观依据。     

基于协同过滤的个性化Web服务选择方法

对传统的Web服务选择算法进行分析,并指出其在动态环境下存在的问题。为了解决该问题,提出了基于协同过滤算法的个性化Web服务选择方法,并设计了一个动态的Web服务选择架构,架构使用协同过滤算法对Web服务的服务质量(QoS)值进行预测并选择最优的Web服务以满足用户的需求。使用150万条真实Web服务的QoS数据与其他4类算法进行了对比实验,结果表明所提方法的可行性和准确性。     

基于QoS本体的Web服务描述和选择机制

随着Web服务数量的急剧增长,如何从大量功能相似的Web服务中选择具有最好的服务质量(Quality of Service,QoS)的Web服务成为研究的热点.提出了一种基于QoS本体支持QoS的服务选择方法,用QoS本体以及相应的词汇来描述QoS数据,基于以上的工作,提出了一种支持QoS的选择机制,将QoS参数的语义匹配度和数值匹配度相结合,利用归一化算法对不同类型的QoS参数取值进行标准化,最后提出了一个公平的,动态的选择机制和相关实验结论.     

基于QoS的Web组合服务绑定技术的研究

如何选择最佳服务是Web服务组合研究领域的重要问题之一.目前工业界和学术界在绑定目标服务时非常关注组合服务的功能匹配,而忽略了非功能属性对组合效果的影响.采用遗传算法优化Web服务QoS(Quality of Service),提出在组合服务实时运行过程中基于QoS进行动态绑定和再绑定的方法,并给出了具体的实施方案.实验显示它可以大大提高Web服务动态组合的运行效率.     

一种基于QoS的网格服务选择机制

开放网格服务体系结构OGSA提出了网格服务的概念，为网格资源的虚拟化管理给出了一条有效途径。当前网格系统对于网格服务的支持主要集中在服务的功能发现与调用部分，缺乏对服务的非功能属性的管理支持。服务的非功能属性如服务的响应时间、价格、可靠性等对于用户来说非常重要，体现着用户对网格服务的QoS需求。基于QoS的服务选择机制能够对网格服务的QoS模型进行管理和度量，对于用户提出的QoS需求，服务匹配算法能够为用户选择满足需求倾向的服务。     

模拟退火算法在Web服务合成中的应用

Web服务使用基于标准的协议,为在线B2B合作提供了前所未有的机会。特别地,把现有的Web服务合成以提供增值的服务就成为研究的热点。面对众多可以提供相同或相似功能的Web服务,根据每个服务提供的非功能属性即服务质量(QoS)进行服务选择就变得至关重要。针对这个问题,提出把具有相同或相似功能的服务组成服务类,设计QoS全局最优的问题模型,并用模拟退火算法求解。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

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.     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

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.