Recently XML has become a standard for data representation and the preferred method of encoding struc- tured data for exchange over the Internet. Moreover it is fre- quently used as a logical format to store structure...Recently XML has become a standard for data representation and the preferred method of encoding struc- tured data for exchange over the Internet. Moreover it is fre- quently used as a logical format to store structured and semi- structured data in databases. We propose a model-driven and configurable approach for modeling hierarchical XML data using object role modeling （ORM） as a flat conceptual model. First a non-hierarchical conceptual schema of the problem domain is built using ORM and then different hierarchical views of the conceptual schema or parts of it are specified by the designer using transformation rules. A hierarchical mod- eling notation called H-ORM is proposed to show these hier- archical views and model more complex semi-structured data constructs and constraints. We also propose an algorithm to map hierarchical H-ORM views to XML schema language.展开更多
BIM数据的存储与传递都主要依靠文件的形式,例如Autodesk的. rvt格式,Industry Foundation Classes格式,在Revit Architecture/Structure/MEP基础上设计的BIM模型大多采用这两种格式.但是,在建筑全生命周期的信息管理中,很难保证模型数...BIM数据的存储与传递都主要依靠文件的形式,例如Autodesk的. rvt格式,Industry Foundation Classes格式,在Revit Architecture/Structure/MEP基础上设计的BIM模型大多采用这两种格式.但是,在建筑全生命周期的信息管理中,很难保证模型数据的一致性、完整性.简述BIM与IFC标准的概念,分析基于IFC的BIM数据库类型,并对基于IFC的BIM半结构化数据库构建进行探讨.展开更多
As the popularity of XML (extensible Markup Language) keeps growing rapidly,the management of XML compliant structured-document databases has become a very interesting andcompelling research area. Query optimization f...As the popularity of XML (extensible Markup Language) keeps growing rapidly,the management of XML compliant structured-document databases has become a very interesting andcompelling research area. Query optimization for XML structured-documents stands out as one of themost challenging research issues in this area because of the much enlarged optimization (search)space, which is a consequence of the intrinsic complexity of the underlying data model of XML data.We therefore propose to apply deterministic transformations on query expressions to mostaggressively prune the search space and fast achieve a sufficiently improved alternative (if not theoptimal) for each incoming query expression. This idea is not just exciting but practicallyattainable. This paper first provides an overview of our optimization strategy, and then focuses onthe key implementation issues of our rule-based transformation system for XML query optimization ina database environment. The performance results we obtained from experimentation show that ourapproach is a valid and effective one.展开更多
文摘Recently XML has become a standard for data representation and the preferred method of encoding struc- tured data for exchange over the Internet. Moreover it is fre- quently used as a logical format to store structured and semi- structured data in databases. We propose a model-driven and configurable approach for modeling hierarchical XML data using object role modeling （ORM） as a flat conceptual model. First a non-hierarchical conceptual schema of the problem domain is built using ORM and then different hierarchical views of the conceptual schema or parts of it are specified by the designer using transformation rules. A hierarchical mod- eling notation called H-ORM is proposed to show these hier- archical views and model more complex semi-structured data constructs and constraints. We also propose an algorithm to map hierarchical H-ORM views to XML schema language.
文摘BIM数据的存储与传递都主要依靠文件的形式,例如Autodesk的. rvt格式,Industry Foundation Classes格式,在Revit Architecture/Structure/MEP基础上设计的BIM模型大多采用这两种格式.但是,在建筑全生命周期的信息管理中,很难保证模型数据的一致性、完整性.简述BIM与IFC标准的概念,分析基于IFC的BIM数据库类型,并对基于IFC的BIM半结构化数据库构建进行探讨.
基金Supported by the National Science Foundation of China(40672104)Special Foundation for Excellent Talents of Beijing (2009D005022 000006)+2 种基金National Science and Technology Support Program (2006BAK01A02-07)the Science Foundation of Beijing Union University (zk201018x)the University Talents Project of Beijing Union University~~
文摘As the popularity of XML (extensible Markup Language) keeps growing rapidly,the management of XML compliant structured-document databases has become a very interesting andcompelling research area. Query optimization for XML structured-documents stands out as one of themost challenging research issues in this area because of the much enlarged optimization (search)space, which is a consequence of the intrinsic complexity of the underlying data model of XML data.We therefore propose to apply deterministic transformations on query expressions to mostaggressively prune the search space and fast achieve a sufficiently improved alternative (if not theoptimal) for each incoming query expression. This idea is not just exciting but practicallyattainable. This paper first provides an overview of our optimization strategy, and then focuses onthe key implementation issues of our rule-based transformation system for XML query optimization ina database environment. The performance results we obtained from experimentation show that ourapproach is a valid and effective one.
