882 resultados para semantic web


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Increasingly, people's digital identities are attached to, and expressed through, their mobile devices. At the same time digital sensors pervade smart environments in which people are immersed. This paper explores different perspectives in which users' modelling features can be expressed through the information obtained by their attached personal sensors. We introduce the PreSense Ontology, which is designed to assign meaning to sensors' observations in terms of user modelling features. We believe that the Sensing Presence ( PreSense ) Ontology is a first step toward the integration of user modelling and "smart environments". In order to motivate our work we present a scenario and demonstrate how the ontology could be applied in order to enable context-sensitive services. © 2012 Springer-Verlag.

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The using of the upsurge of semantics web technologies gives a possibility for an increasing of the flexibility, extensibility and consistency of the existent industrial standards for modeling of web services. In the paper the types of semantic description of web services and the degree of their realization in BPEL4WS (Business Process Execution Language for Web Services) respectively on the abstract and executable level are treated. The methods for using of BPEL4WS for the purposes of semantic web services in the direction of their semi-automatic integration are suggested.

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The next phase envisioned for the World Wide Web is automated ad-hoc interaction between intelligent agents, web services, databases and semantic web enabled applications. Although at present this appears to be a distant objective, there are practical steps that can be taken to advance the vision. We propose an extension to classical conceptual models to allow the definition of application components in terms of public standards and explicit semantics, thus building into web-based applications, the foundation for shared understanding and interoperability. The use of external definitions and the need to store outsourced type information internally, brings to light the issue of object identity in a global environment, where object instances may be identified by multiple externally controlled identification schemes. We illustrate how traditional conceptual models may be augmented to recognise and deal with multiple identities.

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This paper demonstrates an experimental study that examines the accuracy of various information retrieval techniques for Web service discovery. The main goal of this research is to evaluate algorithms for semantic web service discovery. The evaluation is comprehensively benchmarked using more than 1,700 real-world WSDL documents from INEX 2010 Web Service Discovery Track dataset. For automatic search, we successfully use Latent Semantic Analysis and BM25 to perform Web service discovery. Moreover, we provide linking analysis which automatically links possible atomic Web services to meet the complex requirements of users. Our fusion engine recommends a final result to users. Our experiments show that linking analysis can improve the overall performance of Web service discovery. We also find that keyword-based search can quickly return results but it has limitation of understanding users’ goals.

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The emergence of semantic technologies to deal with the underlying meaning of things, instead of a purely syntactical representation, has led to new developments in various fields, including business process modeling. Inspired by artificial intelligence research, technologies for semantic Web services have been proposed and extended to process modeling. However, the applicablility of semantic Web services for semantic business processes is limited because business processes encompass wider requirements of business than Web services. In particular, processes are concerned with the composition of tasks, that is, in which order activities are carried out, regardless of their implementation details; resources assigned to carry out tasks, such as machinery, people, and goods; data exchange; and security and compliance concerns.

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The Web is a steadily evolving resource comprising much more than mere HTML pages. With its ever-growing data sources in a variety of formats, it provides great potential for knowledge discovery. In this article, we shed light on some interesting phenomena of the Web: the deep Web, which surfaces database records as Web pages; the Semantic Web, which de�nes meaningful data exchange formats; XML, which has established itself as a lingua franca for Web data exchange; and domain-speci�c markup languages, which are designed based on XML syntax with the goal of preserving semantics in targeted domains. We detail these four developments in Web technology, and explain how they can be used for data mining. Our goal is to show that all these areas can be as useful for knowledge discovery as the HTML-based part of the Web.

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Este trabalho tem por objetivo propor um modelo de ontologia simples e generalista, capaz de descrever os conceitos mais básicos que permeiam o domínio de conhecimento dos jornais on-line brasileiros não especializados, fundamentado tanto na prática quanto conceitualmente, em conformidade com os princípios da Web Semântica. A partir de uma nova forma de classificação e organização do conteúdo, a ontologia proposta deve ter condições de atender as necessidades comuns de ambas as partes, jornal e leitor, que são, resumidamente, a busca e a recuperação das informações.

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Ontologies play a core role to provide shared knowledge models to semantic-driven applications targeted by Semantic Web. Ontology metrics become an important area because they can help ontology engineers to assess ontology and better control project management and development of ontology based systems, and therefore reduce the risk of project failures. In this paper, we propose a set of ontology cohesion metrics which focuses on measuring (possibly inconsistent) ontologies in the context of dynamic and changing Web. They are: Number of Ontology Partitions (NOP), Number of Minimally Inconsistent Subsets (NMIS) and Average Value of Axiom Inconsistencies (AVAI). These ontology metrics are used to measure ontological semantics rather than ontological structure. They are theoretically validated for ensuring their theoretical soundness, and further empirically validated by a standard test set of debugging ontologies. The related algorithms to compute these ontology metrics also are discussed. These metrics proposed in this paper can be used as a very useful complementarity of existing ontology cohesion metrics.

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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展

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在语义Web服务中, 确认分布式本体变动、维护其一致性并实现基于进化的分布式本体的Web服务语义查询成为了一个重要挑战.该文使用SHOQ(D)的分布式描述逻辑扩展 (DDL) 描述相互关联的异构分布式本体,提出了优先分布式知识库(PDK)的概念,探讨了PDK方法的一些重要属性.PDK用来描述分布式本体的进化和更新, 它适用于语义Web服务环境.基于PDK, 文中还给出了相应的语义查询方法,Web服务的语义查询可以归结为检测同这个查询对应的概念在最优先PDK中的p -可满足性.

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在开放的互联网环境中,面向服务的计算(Service-Oriented Computing, SOC)和面向服务的体系架构(Service-Oriented Architecture, SOA)使得信息资源和软件系统的主要形态发生了巨大变化,并引领着互联网计算技术和软件系统新的发展方向。服务是SOC和SOA的核心思想,服务的平台独立、高可重用和松散耦合等特性使之成为复杂分布式应用可行的解决方案。Web服务的出现和发展为实施与部署SOC和SOA提供了最佳支撑技术。目前web服务发现机制在服务描述的全面性和服务匹配方法的有效性方面存在不足之处,难以保证服务发现的性能。特别是在服务数量剧增的情况下,用户亟需一种自动快速而准确的服务发现机制。语义web技术不仅为web的表示内容提供了一种语义标识方法,推动了web内容的自动化和智能化搜索,也为web服务的描述提供了增加语义层次内容的有效方法,两者的结合形成了一个新的研究领域——语义web服务。该领域通过借鉴语义web的相关技术来增加web服务的语义描述,进而为web服务的发现、组合、调用和监控等环节提供语义层次的支持,增强web服务的自动化和智能化水平。 本文的研究目的就是利用语义web的思想,基于SOC和SOA的理念以及现有的web服务发现机制对web服务信息进行语义描述、组织,探索语义web服务匹配与发现的关键问题,提出有效的解决方案。本文的研究工作和贡献主要在以下四个方面: 1. 针对语义近似度的度量和计算问题基于OWL(Web Ontology Language)提出了一个语义近似度计算SSM模型,该模型中所有概念及概念之间的关系、所有的概念属性及属性之间的关系都被抽象定义并建模,根据概念、属性及其语义关系模型,构建了基于概念关系的拓扑近似度计算函数和属性近似度计算函数,从而进一步构建语义近似度计算函数。该语义近似度计算函数以代表OWL本体概念上下级关系和等价关系的树状结构为基础,利用概念间的拓扑关系和属性关系进行语义近似度的度量和计算。语义近似度函数的返回值为一个介于0与1之间的数值,代表函数的两个输入概念之间的语义近似度值。 2. 提出了一个基于概念语义近似度的以OWL-S为顶层本体的web服务语义匹配PSM模型。该模型将服务的匹配项分为服务能力、服务质量、服务名称和服务参数四个部分。基于该模型,提出了相应的PSM服务匹配算法。PSM算法能够对服务内部的服务流程及流程的组合进行与服务请求的语义匹配,并且避免了服务流程中互斥接口参数参与匹配。而且PSM匹配算法实现了服务接口的单射匹配,进一步提高服务发现的性能。在服务质量匹配计算上,提出了服务质量匹配模型PSM-QoS,为服务的QoS匹配建立了计算基础。PSM算法使用语义近似度计算函数度量和计算服务属性概念的语义近似度值,从而能够返回细粒度的服务匹配度值。 3. 在语义服务匹配PSM模型的基础上提出一种语义web服务发现架构系统PSM-SD模型。该模型将OWL-S语义元素引入UDDI服务描述,从而在UDDI中保存语义信息。通过PSM算法提高web服务匹配性能,并通过数据映射机制保证模型对于当前的服务发现标准UDDI基础架构的兼容以及UDDI标准操作接口的透明性。模型使用本体概念的索引机制提高服务发现的效率。在建立和维护索引的过程或服务的匹配过程中,模型使用近似概念搜寻算法进一步提高本体概念搜寻和服务匹配的效率。 4. 设计并开发了基于语义web服务发现架构模型的原型系统。该系统将语义近似度计算模型、语义web服务匹配模型和语义web服务发现架构模型进行软件实现。本文在该原型系统平台上对语义web服务发现的方法进行了实验,验证了方法的有效性。

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随着Web信息的与日俱增,使用机器处理这种信息成为一种必然的趋势。语义Web应运而生,成为当前研究的热点之一。它以本体为核心,为不同领域提供共享的词汇,以便机器处理Web信息。表达本体的标准语言OWL以描述逻辑为基础。OWL本体的推理可伸缩性差,难以适应规模较大的本体应用,因此推理可伸缩性问题是一个重要的实际问题。此外,OWL本体是一个逻辑系统,在生成、维护和集成等过程中,都很容易出现非一致现象,导致标准的推理机制不能正常运作。因此本体非一致问题是另一个重要的实际问题。针对上述两个实际问题,本文分别在实现可伸缩推理、修复非一致本体、以及进行非一致容忍推理三个方面提出了解决办法。 [可伸缩推理方面] 本文提出了一种本体断言公理集的划分方法,使本体推理能够在独立的划分子集中进行,以此提高本体推理的可伸缩性。 [本体修复方面] 本文提出了一种计算具有最小删除代价的本体子集的方法;通过删除这种本体子集,可以恢复本体的一致性。该方法将计算上述本体子集的问题归约为在命题逻辑程序中计算某种最优模型的问题,以调用现有的可满足性问题求解器来解决。 [非一致容忍推理方面] 本文将命题逻辑中字典序推理方法应用到描述逻辑中,以提供针对非一致本体的查询机制。本文还提出了一种在描述逻辑本体中进行字典序推理的方法。该方法将字典序结论的判定问题归约为命题可满足性判定问题,以调用现有的可满足性问题求解器来解决。

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随着Internet上异构应用系统的大量增加和SOA技术的空前发展,Web服务技术变得越来越重要,已经成为了学术界和工业界关注的热点。在Web服务技术中,服务发现为Web服务消费者调用Web服务提供者提供的服务提供了桥梁,起到非常重要的承接作用,成为了Web服务技术中的重点。目前的Web服务发现机制主要有两种,第一种是传统的Web服务发现方式,主要基于UDDI(Universal Description, Discovery and Integration)的纯粹关键字查找;第二种是基于Web服务的语义信息,进行Web服务间的语义匹配。 第一种方法的基础UDDI是国际标准,而且应用也最为广泛,但UDDI中对于Web服务的描述是基于语法的,而且缺乏Web服务所特有的I/O属性和服务质量属性等信息。第二种方法基于Web服务的语义信息,包括Web服务所特有的I/O属性,但因为缺乏灵活有效的Web服务匹配方法和与之对应的Web服务匹配框架,限制了其应用。 基于此,本文在对当前语义Web服务匹配技术分析和研究的基础上,对当前的语义Web服务匹配方法进行了改进,同时提出了基于过滤器(filter)的语义Web服务匹配框架模型。本文的主要工作有: 1)对目前的语义Web服务匹配技术进行了较为全面深入的探讨和综述。 2)对当前的语义Web服务匹配的各个阶段进行了详细的分析,对其中的匹配方法进行了改进。提出了基于向量空间模型(VSM)和TF-IDF(Term Frequency–Inverse Document Frequency)思想的本体权重的计算方法,本体层次关系图中边的权重的计算方法和本体之间相似度的计算方法。 3)提出了基于web服务黑盒属性的语义。 4)语义Web服务匹配框架方面,本文提出了基于filter的语义Web服务匹配框架,并将其延伸到非语义Web服务系统中。

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语义Web是现有Web的一个语义延伸,目标是使Web的应用具有一定的智能,能够进行更准确的信息搜索和一定的决策支持,帮助用户自动完成一些任务。语义Web的实现需要人工智能、数据库等领域的技术支持,需要对已有的技术进行改进和扩展,也需要对现有技术本身如ECA规则进行更深入的研究从而进一步将其扩展到语义Web。自动推理技术是语义Web实现的基础之一,而ECA规则可以为系统增加反应性行为能力,本文围绕自动推理和ECA规则,主要进行了如下研究:(1) 一阶逻辑推理技术对语义Web的推理支持。分析了语义Web语言需要的表达能力,对现有描述逻辑工具、一阶逻辑工具的能力进行了考察。现有的描述逻辑工具不足以处理应用所需要的更丰富的语言成分、任意的一阶逻辑规则等,而一阶逻辑自动定理证明工具和有限模型查找工具有分别都有较好的研究成果。把语义Web的推理问题化成可满足性判定问题后,本文给出了一阶逻辑定理证明器和有限模型查找器形成的并发过程进行可满足性判定的方法。这样既可以解决描述逻辑工具的不足,并可弥补定理证明器对可满足的公式推理的不完备性。(2) ECA规则(主动规则)的终止性分析。终止性是主动规则最重要的行为性质,不终止是由于主动规则的级联触发造成的,意味着定义错误。终止性检查通常是不可判定的。有效的静态分析方法是主动规则得以实际应用的保证。静态分析的关键是合适的数据库状态描述,本文给出用约束表示数据库状态的方法,通过模拟规则执行,使用约束求解进行条件计算和重复状态检查,判断主动规则集合是否终止。用约束精确表示了数据库状态,在规则处理中考虑了执行语义,从而得到更精确的终止性结论。

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语义WebWeb服务是当前热门的应用技术,而两者的结合——语义Web服务将在未来几年具有极大的应用前景。语义使得~Web~服务的自动发现和自动组装变得非常容易、高效,但是随之而来的问题是如何确保自动组装的~Web~服务组合在本体知识库的状态下是一致的,并且在执行过程中也始终保持一致。 本文介绍了一种基于路径的语义Web服务组合验证方案,通过对服务组合中的单个Web服务进行输入、输出、前置条件和执行效果(IOPE)进行语义标注,旨在找出组合执行过程中在任何结点处可能存在的不一致性。文章定义了显式不一致性和隐式不一致性,首先提出了语义Web服务前置条件和执行效果的正规化表示方法,然后介绍了顺序和并发执行的多个Web服务之执行效果自动化累积算法,接下来给出了基于路径的一致性验证算法。文章还给出了实现该验证方案的平台架构,给出了相关实验过程和结果。 文章还完整地介绍了中科院某研究所本体的构造和扩充过程,定义了研究生毕业申请服务组合,并介绍了服务的IOPE标注,最后运用验证方案对该组合进行验证,给出了验证结果。