17 research outputs found

    建構農產運銷物流中心評選模式決策之研究

    Get PDF

    Research on Technology of Automatic Services Composition Based on Semantic Web

    No full text
    语义Web和Web服务是WWW发展的两个重要趋势,这两种技术的结合产生了另一个新兴的研究课题—语义Web服务。语义Web服务是指用语义Web标记语言来描述服务的语义,使Web服务成为计算机可以理解的实体,从而支持服务的自动发现、执行和组合等。本文研究的是基于语义Web的服务自动组合技术,目标是使软件agent能根据用户的需求将各种已有的、Web服务自动地组合起来、协同工作完成用户的任务,使服务可以灵活地满足用户的需求,实现“按需服务”。本文结合国家863课题“语义Web技术与Ontology”,对语义Web服务自动组合的关键技术,包括语义Web标记语言、语义Web服务描述模型和Web服务的自动组合方法进行了研究,主要工作成果包括以下四个方面:(1)设计了一种语义Web规则标记语言—OWL Rule+。针对语义Web层次结构中Web oniology语言OWL在一般规则表达能力方面的不足,在其基础上设计了一种语义Web规则标记语言—OWLRule+,作为语义Web的逻辑规则层。它的语义基于CARIN(一种结合Hom规则和描述逻辑的表示语言),语法是OWL的扩展。这样既结合了OWL的语法和语义特征,又能够标记Horn形式的规则。同时也为OWL-S模型的扩展提供了语言荃础。(2)在现有语义Web服务描述模型OWL-S的基础上进行了扩展和完善,形成增加用户偏好表示的模型—OWL-S+。在OWL-S的基础上增加了用户偏好的表示,扩展为模型OWL-S+,并基于OWLRute+语言定义了相应的OWL-S+本体。OWL-S+不仅包含服务的过程模型,还包含用户偏好的表示方法。由于用户偏好影响着服务的选择,因此OWL-S十模型增加对它的形式化表示后,能更好地支持服务组合的自动化。(3)给出了一种基于OWL-S+模型和状态演算(Situation Calculus,SC)的服务自动组合方法OWL-SC。将状态演算作为支持服务自动组合的形式化手段,在状态演算中增加了意愿公理的表示和处理,使其可以处理用户偏好。并给出了一组从OWL-S+模型到状态演算各项的映射。(4)基于OWL-s十模型和OWL-SC方法设计了自动组合Web服务的多agent系统AWSC-Agents,并进行了实例研究。设计了AWSC叫Agents的体系结构和服务组合规划agent的算法,并基于状态演算语言hidiGolog和多agent开发框架OAA给出了具体的实现机制。还通过一个网上行程安排的演示系统初步验证了OWL-S+模型和OWL-SC方法的适用性和有效性。Semantic Web and Web service are the two important trends which are emerging in the World Wide Web (WWW). The confluence of Web services and the Semantic Web gives birth to another new technology - Semantic Web Services. The Semantic Web markup language can be used to describe the semantics of Web services and make them computer-interpretable entities, so as to enable programs or agents to locate, invoke and compose Web services automatically. This dissertation focuses on the Semantic Web services composition and aims to develop a technology which can automatically and flexibly compose various existing services to fulfill users' tasks according to their requirements, thus realize so-called service on demand. This dissertation discusses several key issues in Semantic Web services composition automation, including Semantic Web markup language, Semantic Web service description model and services composition method. The main points of this dissertation are described as follows: (1) It designs a Semantic Web rule markup language OWLRule+ based on the current W3C Web ontology language OWL. OWL's semantics is limited to description logic, which cannot capture semantics of arbitrary rules. Therefore, OWLRule+ is designed. Its syntax extends OWL and its semantics is based on CARIN, a representation language combining description logic and Horn rules. It does not only provide a logic layer on top of ontology layer for Semantic Web architecture, but also lays the foundation for extension of OWL-S, the current Semantic Web service model. (2) It proposes a new Semantic Web service model called OWL-S+ by enriching OWL-S with the expression power of users' preferences. OWL-S+ model and the corresponding OWL-S+ ontology in OWLRule+ language are defined. The new model contains formal description of user preferences in addition to description of services. It can support automated services composition better than OWL-S, since user preferences affect how to select services. (3) A method for automating services composition is put forward based on OWL-S+ and Situation Calculus. It is named OWL-SC Situation Calculus is chosen as the formalism for automating services composition. And it is extended to enable expression and handling of users' preferences. Mapping method from OWL-S+ to Situation Calculus is given. (4) A multi-agent system for automating Web services composition, called AWSC-Agents, is designed and a demo is implemented. The architecture of AWSC-Agents and the planning agent algorithm are designed. The concrete implementation mechanism based on IndiGolog, a Situation Calculus-based language and OAA, a multi-agent development framework, is also discussed. The usability and validity of the OWL-S+ model and OWL-SC method is proven by a demo agent system which can plan conference trips for Internet users

    a simulation-driven performance testing method for web applications

    No full text
    性能是Web应用程序成功的要素之一 ,性能测试则是保证这一要素的重要手段 但由于Internet及Web用户的不确定性 ,Web应用程序的性能测试难于传统Client/Server的测试 比较了 3种主要的Web性能测试方法 ;提出了一种简单可行的、通用的方法———模拟驱动的自动负载测试方法 关键的步骤有 :根据系统使用方式和客户端各种特征的分布信息来确定测试负载、设计测试用例 ;利用测试工具开发相应的测试脚本 ;运行测试用例模拟不同类型用户的典型行为 ;收集被测程序的性能数据 结合实例详述了该方法 ,并给出了测试计划的模

    an experimental study of response times of web applications

    No full text
    性能测试是保证Web应用程序成功的重要手段 ,但是如果不能采用正确的方法测试或者不能完全理解测试结果对测试环境的依赖性 ,那么测试结果很可能会起误导作用 响应时间则是性能的一个重要指标 ,特别是从用户的角度来看 因此进行了一系列探索性的实验来研究Web应用程序运行响应时间的特性 ,用统计的方法对实验结果做了分析 ,发现Web事务的响应时间和用户数之间呈线性关系 ,测试的时间和测试配置对响应时间也有一定影

    design and implementation of a semantic web rule markup language owlrule+

    No full text
    语义Web是对未来Web体系结构的一个伟大设想 ,其研究分层次进行 目前足够成熟的最高层是以OWL语言为代表的ontology层 但它的语义仅限于描述逻辑 ,该逻辑主要表示对象和类的层次结构 ,而规则的表达能力弱 因此在其之上需要一种表达力更丰富的逻辑语言 设计了一种新的语义Web规则标记语言OWLRule+:其语法扩展了OWL ;语义基于CARIN ,一种结合描述逻辑和Horn规则的表示语言 ;实现基于Jess规则推理机 实例学习展示了它对目前的Webontology语言在规则表示和推理能力上的扩

    用于无线快衰落信道的快速自适应估计新算法

    No full text

    基于主客体识别的自愈合功能材料

    No full text
    近年来,自愈合材料的研究引起了广泛的兴趣,已报道的自愈合材料大多为结构性自愈合材料。具有特殊光、电等性能的功能性自愈合材料尚处于初期研究阶段。本课题组基于环糊精自组装的研究发展了一系列自愈合功能材料。1)自愈合缓冲材料。二茂铁改性的聚乙烯亚胺和环糊精修饰的多官能脂肪酸形成的超分子材料具有良好的缓冲性能,愈合前后材料的缓冲性能基本相同。2)自愈合导电材料。发展了两类自愈合导电材料:金刚烷改性的聚乙烯亚胺和丙烯酸乙二醇酯分别与环糊精改性的碳纳米管形成的复合材料。该系列自愈合材料表现出优异的弹性、机械性能和导电性能。3)自愈合多功能涂料。基于课题组构筑自愈合功能材料的理念,制备了含有Fe_3O_4和..

    Fabrication of Gold Nanoparticles Array Film as Surface-Enhanced Raman Spectroscopy Substrate

    No full text
    表面增强拉曼光谱(SERS)是一种灵敏度很高的分析技术,可以给出分子水平的光谱信息,常被用于痕量分析检测。金纳米颗粒(AuNPs)由于其可控制备、独特的光学特性,是最常用的SERS基底材料之一。然而,如何经济、高效地制备出一种性质稳定、耐保存的拉曼基底材料,仍是亟待解决的问题。文中通过静电纺丝工艺,将修饰了beta-环糊精的AuNPs聚合液制备成静电纺丝薄膜;将此薄膜用作SERS基底材料,以罗丹明6G作为探针分子,获得了优异的SERS效果,增强因子约为105,检测限达到10-6级以下,且基底材料的重复性优越

    Seedborne diseases and their control

    No full text
    Describes the principles derived from our knowledge of the biology of seedborne pathogens and how these are applied in the practical control of seedborne diseases. The pathogens covered are seedborne fungi, bacteria and viruses which attack temperate and tropical field crops. The main part of the book is concerned with the processes of infection of seeds, the location and the survival of inoculum, and the transmission and spread of seedborne pathogens. The author then describes how, with this knowledge, strategies and methods have been developed and employed at national and international levels to exclude and eradicate seed transmitted diseases. Effective methods for the detection of seedborne inoculum are necessary throughout and a specific chapter is devoted to these technologies. The book is written for practicing plant pathologists as well as for students of plant pathology seeking a general review text of this subject area. It is also highly relevant to workers in the agrochemical industry with special interests in seed treatment and seed treatment methods. Seedbome diseases and their control: principles and practice by R B Maude 1995 288pp price UKL £40.00 ISBN 0 85198 922 5 available from: CAB International Wallingford, Oxon OX10 8DE, UKSeedborne diseases and their control: principles and practice by R B Maude 1995 288pp price UKL £40.00 ISBN 0 85198 922 5 available from: CAB International Wallingford, Oxon OX10 8DE, U
    corecore