The increased number of data repositories has greatly increased the availability of open data.To enable broad discovery and access to research dataset,some data repositories have begun leveraging the web architecture ...The increased number of data repositories has greatly increased the availability of open data.To enable broad discovery and access to research dataset,some data repositories have begun leveraging the web architecture by embedding structured metadata markup in dataset web landing pages using vocabularies from Schema.org and extensions.This paper aims to examine metadata interoperability for supporting global data discovery.Specifically,the paper reports a survey on which metadata schema has been adopted by participating data repositories,and presents an analysis of crosswalks from fourteen research data schemas to Schema.org.The analysis indicates most descriptive metadata are interoperable among the schemas,the most inconsistent mapping is the rights metadata,and a large gap exists in the structural metadata and controlled vocabularies to specify various property values.The analysis and collated crosswalks can serve as a reference for data repositories when they develop crosswalks from their own schemas to Schema.org,and provide the research data community a benchmark of structured metadata implementation.展开更多
Multidatabase systems are designed to achieve schema integration and data interoperation among distributed and heterogeneous database systems. But data model heterogeneity and schema heterogeneity make this a challeng...Multidatabase systems are designed to achieve schema integration and data interoperation among distributed and heterogeneous database systems. But data model heterogeneity and schema heterogeneity make this a challenging task. A multidatabase common data model is firstly introduced based on XML, named XML-based Integration Data Model (XIDM), which is suitable for integrating different types of schemas. Then an approach of schema mappings based on XIDM in multidatabase systems has been presented. The mappings include global mappings, dealing with horizontal and vertical partitioning between global schemas and export schemas, and local mappings, processing the transformation between export schemas and local schemas. Finally, the illustration and implementation of schema mappings in a multidatabase prototype - Panorama system are also discussed. The implementation results demonstrate that the XIDM is an efficient model for managing multiple heterogeneous data sources and the approaches of schema mapping based on XIDM behave very well when integrating relational, object-oriented database systems and other file systems.展开更多
文摘The increased number of data repositories has greatly increased the availability of open data.To enable broad discovery and access to research dataset,some data repositories have begun leveraging the web architecture by embedding structured metadata markup in dataset web landing pages using vocabularies from Schema.org and extensions.This paper aims to examine metadata interoperability for supporting global data discovery.Specifically,the paper reports a survey on which metadata schema has been adopted by participating data repositories,and presents an analysis of crosswalks from fourteen research data schemas to Schema.org.The analysis indicates most descriptive metadata are interoperable among the schemas,the most inconsistent mapping is the rights metadata,and a large gap exists in the structural metadata and controlled vocabularies to specify various property values.The analysis and collated crosswalks can serve as a reference for data repositories when they develop crosswalks from their own schemas to Schema.org,and provide the research data community a benchmark of structured metadata implementation.
文摘Multidatabase systems are designed to achieve schema integration and data interoperation among distributed and heterogeneous database systems. But data model heterogeneity and schema heterogeneity make this a challenging task. A multidatabase common data model is firstly introduced based on XML, named XML-based Integration Data Model (XIDM), which is suitable for integrating different types of schemas. Then an approach of schema mappings based on XIDM in multidatabase systems has been presented. The mappings include global mappings, dealing with horizontal and vertical partitioning between global schemas and export schemas, and local mappings, processing the transformation between export schemas and local schemas. Finally, the illustration and implementation of schema mappings in a multidatabase prototype - Panorama system are also discussed. The implementation results demonstrate that the XIDM is an efficient model for managing multiple heterogeneous data sources and the approaches of schema mapping based on XIDM behave very well when integrating relational, object-oriented database systems and other file systems.
