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Catalogue service is crucial to the sharing and utilizing of geographic information. This paper provides a new architecture and its implementation of a geographic information catalogue service that can effectively manage distributed geographic data and services. The catalogue service is based on the Open Geospatial Consortium (OGC) Catalogue Service for Web(More)
It is now common for academic institutes, government sectors and commercial corporations all over the world to engage in collaborative, complex applications. Most of them require international and interoperable access to large quantities of distributed, heterogeneous geospatial data, services, computing abilities and other facilities. The open grid services(More)
This paper presents the work performed for the implementation of the geospatial product virtualization in the Grid environment. A virtual geospatial product is a product that does not exist in a geospatial data system but the system knows how to create such a product when a user requests the product. We use a two-step approach to the implementation. The(More)
Estimating exposures to PM2.5 within urban areas requires surface PM2.5 concentrations at high temporal and spatial resolutions. We developed a mixed effects model to derive daily estimations of surface PM2.5 levels in Beijing, using the 3 km resolution satellite aerosol optical depth (AOD) calibrated daily by the newly available high-density surface(More)
The synchronisation of time and frequency between remote locations is crucial for many important applications. Conventional time and frequency dissemination often makes use of satellite links. Recently, the communication fibre network has become an attractive option for long-distance time and frequency dissemination. Here, we demonstrate accurate frequency(More)