10 resultados para Semantic technologies

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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表面技术能够显著提高材料功能而成为工程和产品设计的重要组成部分, 但前提是表面技术必须具有可设计性。为此, 需要开拓和发展表面组合加工技术, 进行创新。该技术的内涵体现了新材料与新技术、基础研究与产业化有机结合的特点, 具有重要的价值和广阔的前景。

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Quadratic optical nonlinearity chi((2)) can be exploited in femtosecond lasers and regarded as a significant new degree of freedom for the design of short-pulse sources. We will review our recent progress on developing nonlinear quadratic technologies for femtosecond lasers. Our nonlinear laser technology offers new properties for femtosecond lasers, including optical parametric amplifier with novel working regime, efficient second harmonic generation, and time telescope.

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The novel material of photonic crystal makes it possible to control a photon, and the photonic integration will have breakthrough progress due to the application of photonic crystal. It is based on the photonic crystal device that the photonic crystal integration could be realized. Therefore, we should first investigate photonic crystal devices based on the active and the passive semiconductor materials, which may have great potential application in photonic integration. The most practical and important method to fabricate two-dimensional photonic crystal is the micro-manufacture method. In this paper, we summarize and evaluate the fabrication methods of two-dimensional photonic crystal in near-infrared region, including electron beam lithography, selection of mask, dry etching, and some works of ours. This will be beneficial to the study of the photonic crystal in China.

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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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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。