面向虚拟地理环境的语义数据模型*

针对当前虚拟地理环境中语义信息表达不足问题,提出了一种面向虚拟地理环境的语义数据模型,能够有效表达几何信息、拓扑信息、语义信息和属性信息,并对这些信息进行关联来表达实体。设计了面向虚拟地理环境的集成空间数据结构,综合表达地上、地表和地下空间实体,通过实体的分类和分解来表达实体的语义信息;依据此语义数据模型,实现了地上建筑物和地形的无缝集成。该语义数据模型能够对虚拟地理环境中的实体进行无歧义表达。     

Applying intelligent agents and semantic web services in eGovernment environments

The increasing volume of eGovernment‐related services is demanding new approaches for service integration and interoperability in this domain. Semantic web (SW) technologies and applications can leverage the potential of eGovernment service integration and discovery, thus tackling the problems of semantic heterogeneity characterizing eGovernment information sources and the different levels of interoperability. eGovernment services will therefore be semantically described in the foreseeable future. In an environment with semantically annotated services, software agents are essential as the entities responsible for exploiting the semantic content in order to automate some tasks, and so enhance the user's experience. In this paper, we present a framework that provides a seamless integration of semantic web services and intelligent agents technologies by making use of ontologies to facilitate their interoperation. The proposed framework can assist in the development of powerful and flexible distributed systems in complex, dynamic, heterogeneous, unpredictable and open environments. Our approach is backed up by a proof‐of‐concept implementation, where the breakthrough of integrating disparate eGovernment services has been tested.     

A distributed semantic network model for a collaborative intelligent system

A methodology based on topology theory to model a semantic network for a collaborative system is given. This framework is used to support the creation of a semantic network and to define the associated intelligent cooperative system. Our methodology is illustrated via a set of agents whose knowledge-base is a semantic network. By a series of functions applied on a base of entities, issued from the application domain, a family of sets are synthesized with their subspaces correlated. The resultant subspaces and their relations form a network of elementary and complex concepts that can be naturally represented with the IDEF1x language. A prototype Multi-Agent System (MAS), set up with the Zeus platform,¹ was developed for the Process Plan domain, which was used as a case study. Full correspondence among the subspaces, the semantic network IDEF1x information model and the MAS implementation is obtained by employing this framework.     

Conceptual framework for document semantic modelling: an application to document and knowledge management in the legal domain

The main contribution of this paper is to lay down a conceptual framework for document semantics modeling. This framework provides a generic graphical knowledge representation model based on Sowa’s conceptual structures. Modeling primitives are introduced to represent factual and ontological knowledge that can be expressed in electronic documents. Binding features are proposed so as to keep knowledge representation and knowledge formulation linked together.

This framework may be applied to various domains and may accept, for this purpose, many different ontological extensions. Thus an extension is provided so as to properly handle the particular kind of knowledge encountered in the legal domain.     

面向资源融合网格的数据语义框架

当前语义web服务成了语义web研究和应用的热点之一,提出了几种语义web服务框架,但是这些架构主要是用于web服务的自动发现、自动调用、自动服务纽合,不适合描述网格环境下的数据语义。本文在目前的语义web服务框架基础上,提出面向资源容融合网格（FuseGrid）的数据语义框架（ODSF）。在ODSF中,数据对象的语义是自描述的;ODSF包括4个顶层元素,分别为元属性、数据库本体、映射以及业务规则,其中元属性、数据库本体以及映射本体表示数据对象的静态语义,而业务规则描述数据对象的动态语义。同时分析了该框架的语义数据访问方法及其关键算法。     

基于语义网格的E-Learning平台研究

E-Learning是信息时代重要的学习方式,它旨在打破时间和空间的限制,支持大规模范围的资源共享和学习协作,提供个性化和自适应的学习环境.在分析语义Web和网格计算对E-Learning开发的支持作用的基础上,提出了基于语义网格的E-Learning平台体系结构框架,面向服务的语义网格中间件是核心.对提出的E-Learning平台体系结构框架的层次结构进行了分析,描述了各层的功能划分和组成,最后探讨了通用E-Learning平台的组件化构建策略.     

基于多代理的分布式构件库系统框架

本文提出了一个基于多代理的用于主动服务的分布式构件库系统框架,并将构件语义网络应用到该系统框架之中。在局域网环境下,根据分布式构件库系统框架实现了一个原型系统,该系统能够实现基于语义导航的构件搜索、构件间关系的展现,以及基于移动代理的构件搜索过程。基于多代理的分布式构件库系统框架具有一定的智能性和良好的扩展性。     

社会语义网分析技术研究

为满足在线社会网络语义分析的需要,提出社会语义网络分析框架。该框架由两部分构成:一是在线社会网络的语义表示,利用RDF模型和已建立的本体描述在线社会网络,赋予社会网络丰富的语义信息;二是在线社会网络的语义分析,利用SPARQL对在线社会网络语义图进行检索过滤,获取满足语义要求的数据,在分析过程中利用属性的层次结构实现分析粒度的控制,通过属性路径检索实现整体网分析。通过应用案例,说明了所提框架的有效性。     

语义规则驱动的中国古代建筑造型

根据中国古代建筑具有完整的营造规则约束的特点,提出了一种语义规则驱动的快速建模方法．根据中国古代建筑的建造规范,从中提取出若干造型规则,并且参数化表示主要的建筑结构特征,利用它们来控制模型的生成．定义了模型的构造模块——组件,通过迭代解释造型规则来控制组件的变换和组合,从而构造出一系列的中国古代建筑模型．通过扩充纹理库,可以得到不同效果的建筑模型．     

A Semantic Cache Framework for Secure XML Queries

Secure XML query answering to protect data privacy and semantic cache to speed up XML query answering are two hot spots in current research areas of XML database systems. While both issues are explored respectively in depth,they have not been studied together,that is,the problem of semantic cache for secure XML query answering has not been addressed yet. In this paper,we present an interesting joint of these two aspects and propose an efficient framework of semantic cache for secure XML query answering,which can improve the performance of XML database systems under secure circumstances. Our framework combines access control,user privilege management over XML data and the state-of-the-art semantic XML query cache techniques,to ensure that data are presented only to authorized users in an efficient way. To the best of our knowledge,the approach we propose here is among the first beneficial efforts in a novel perspective of combining caching and security for XML database to improve system performance. The efficiency of our framework is verified by comprehensive experiments.     

Active semantic caching to optimize multidimensional data analysis in parallel and distributed environments

In this paper, we present a multi-query optimization framework based on the concept of active semantic caching. The framework permits the identification and transparent reuse of data and computation in the presence of multiple queries (or query batches) that specify user-defined operators and aggregations originating from scientific data-analysis applications. We show how query scheduling techniques, coupled with intelligent cache replacement policies, can further improve the performance of query processing by leveraging the active semantic caching operators. We also propose a methodology for functionally decomposing complex queries in terms of primitives so that multiple reuse sites are exposed to the query optimizer, to increase the amount of reuse. The optimization framework and the database system implemented with it are designed to be efficient irrespective of the underlying parallel and/or distributed machine configuration. We present experimental results highlighting the performance improvements obtained by our methods using real scientific data-analysis applications on multiple parallel and distributed processing configurations (e.g., single symmetric multiprocessor (SMP) machine, cluster of SMP nodes, and a Grid computing configuration).     

教学文档中图像的本体构建

为了使得广大高校教师和学生能够快速准确地进行信息检索和知识获取,以便了解本学科前沿领域知识,研究开发了一个基于语义Web的教研辅助系统平台,本文就该平台中图像的本体构建问题进行了探讨.按照图像所属的学科专业、课程和图像所表达的主题对图像进行分类,并用Web本体语言OWL来对本体进行描述.     

基于Word Embedding语义相似度的字母缩略术语消歧

该文提出基于Word Embedding的歧义词多个义项语义表示方法,实现基于知识库的无监督字母缩略术语消歧。方法分两步聚类,首先采用显著相似聚类获得高置信度类簇,构造带有语义标签的文档集作为训练数据。利用该数据训练多份Word Embedding模型,以余弦相似度均值表示两个词之间的语义关系。在第二步聚类时,提出使用特征词扩展和语义线性加权来提高歧义分辨能力,提高消歧性能。该方法根据语义相似度扩展待消歧文档的特征词集合,挖掘聚类文档中缺失的语义信息,并使用语义相似度对特征词权重进行线性加权。针对25个多义缩略术语的消歧实验显示,特征词扩展使系统F值提高约4%,使用语义线性加权后F值再提高约2%,达到89.40%。     

Frameworks for incorporating semantic relationships into object‐oriented database systems

A semantic relationship is a data modeling construct that connects a pair of classes or categories and has inherent constraints and other functionalities that precisely reflect the characteristics of the specific relationship in an application domain. Examples of semantic relationships include part–whole, ownership, materialization and role‐of. Such relationships are important in the construction of information models for advanced applications, whether one is employing traditional data‐modeling techniques, knowledge‐representation languages or object‐oriented modeling methodologies. This paper focuses on the issue of providing built‐in support for such constructs in the context of object‐oriented database (OODB) systems. Most of the popular object‐oriented modeling approaches include some semantic relationships in their repertoire of data‐modeling primitives. However, commercial OODB systems, which are frequently used as implementation vehicles, tend not to do the same. We will present two frameworks by which a semantic relationship can be incorporated into an existing OODB system. The first only requires that the OODB system support manifest type with respect to its instances. The second assumes that the OODB system has a special kind of metaclass facility. The two frameworks are compared and contrasted. In order to ground our work in existing systems, we show the addition of a part–whole semantic relationship both to the ONTOS DB/Explorer OODB system and the VODAK Model Language. Copyright © 2003 John Wiley & Sons, Ltd.     

施事的语义分布考察与动词的语义特征

在自然语言处理中,语义角色标注是一个比较重要的任务。语义角色标注任务以语义角色理论为基础。语义角色标注任务和语言学的相关理论都要求同一个动词在不同语句中相应的语义角色成分保持一致。该文统计了北京大学973课题语义角色标注语料库及中文PropBank中“施事”的语义分布,进而根据该语义分布,加上人工筛选,共找出了85个在“施事”语义角色的标注上无法保持一致的动词。该文指出,这些动词的 “施事”语义无法保持一致的原因在于它们是一类有致使语义特征、无自主语义特征的动词。该文的研究对于处理其他语义角色(如“客体”)也存在的标注不一致问题有一定的启示。     

离散ADMM方法下像素与对象基元协同优化的遥感影像无监督语义分割

语义分割是遥感影像分析中的重要技术之一。现有的方法（如基于深度卷积神经网络的方法等）虽然在语义分割中取得了显著进展,但往往需要大量训练数据。基于图模型的马尔可夫随机场模型（Markov random field model,MRF）提出了一种不依赖训练数据的无监督语义分割思路,可以有效地刻画地物空间关系,并对地物空间分布的统计规律进行建模。但现有的MRF模型方法通常建立在基于像素或对象的单一粒度基元上,难以充分利用影像信息,语义分割效果不佳。针对上述问题,引入交替方向乘子法 （alternative direction method of multiplier,ADMM）并将其离散化,提出了一种像素与对象基元协同的MRF模型无监督语义分割方法（MRF-ADMM）。首先构建像素基元和对象基元两个概率图,其中像素基元概率图用于刻画影像的细节信息,保持语义分割的边界;对象基元概率图用于描述较大范围的空间关系,以应对遥感影像地物内部的高异质性,使分割结果中地物内部具有良好的区域完整性。在模型求解过程中,针对像素和对象基元的特点,提出了一种离散化的ADMM方法,并将其用于两种基元类别标记的传递与更新,实现像素基元细节信息和对象基元区域信息的协同优化。高分二号和航拍影像等不同数据库不同类型遥感影像的语义分割实验结果表明,相较于现有的MRF模型,提出的MRF-ADMM方法能有效地协同不同粒度基元的优点,优化语义分割结果。     

A logical foundation for the semantic Web

World Wide Web (WWW) has been one of important channels from which people acquire information and services, but most web pages are only used by humans at pre-sent, and these pages cannot be processed and understood automatically by computers. The semantic Web is an essential reformation of Web. The main objective of the seman-tic Web is to enrich Web with semantics and make Web be understood by computers, in order to communicate and cooperate between people and computer. The key of the se-…     

An ontology,intelligent agent-based framework for the provision of semantic web services

Intelligent agents and semantic web services are two technologies with great potential. Striking new applications can be developed by using the tools and techniques they provide. However, semantic web services need for an upper software entity able to deal with them and, on the other hand agent technology has historically suffered from a number of drawbacks that must be addressed. Integrating these two technologies in a joint environment can overcome their problems while strengthening their advantages. In this paper, the necessity for integrating these technologies and the potential benefits of their combination are analyzed. Based on this study, we present SEMMAS, an ontology-based framework for seamlessly integrating Intelligent Agents and Semantic Web Services. The basics of the framework are detailed and a proof-of-concept implementation described.     

语义物联网中一种多领域信息互操作方法

针对当前语义物联网尚未形成一套比较完善、可共享的语义系统,无法支持不同领域资源描述和语义互操作性问题,提出了一个语义物联网中基于多个领域本体及链接开放数据的语义互操作方法。该方法可以半自动化标注新部署的传感器,为传感器数据添加语义,使机器理解数据含义,并对其进行推理;采用本体实体表管理同一领域本体,来规范统一本体;基于链接开放数据获取命名实体相关的语义,对信息进行补充。最后通过具体实例阐述其工作过程,并与其它经典的方法进行比较。结果表明,其可以较好的实现多领域信息的互操作。