Ralf-Erik Ebert

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The Grist project is developing a grid-technology based system as a research environment for astronomy with massive and complex datasets. This knowledge extraction system will consist of a library of distributed grid services controlled by a workflow system, compliant with standards emerging from the grid computing, web services, and virtual observatory(More)
The recent upsurge in astrophysical research applications of grid technologies, coupled with the increase in temporal and spatial sky-coverage by dedicated all-sky surveys and on-line data archives, have afforded us the opportunity to develop an automated image reduction and analysis pipeline. Written using Python and Pyraf, the Python implementation of the(More)
We describe the activity done in the contest of the Grid.it project to access Astronomical Catalogues and Archives through grid environment. Different approaches are tested: job oriented, web service oriented. The crucial aspect of this work is the development and deployment of an IVOA compliant Data Source Engine model in the grid middleware.
The Grist project is developing a grid-technology based system as a research environment for astronomy with massive and complex datasets. This knowledge extraction system will consist of a library of distributed grid services controlled by a workflow system, compliant with standards emerging from the grid computing, web services, and virtual observatory(More)
One of the new frontiers of astronomical research is the exploration of time variability on the sky at different wavelengths and flux levels. We have carried out a pilot project using DPOSS data to study strong variables and transients, and are now extending it to the new Palomar-QUEST synoptic sky survey. We report on our early findings and outline the(More)
We describe the architecture of the Japanese Virtual Observatory (JVO) prototype system version 2. JVO aims at seamless access to astronomical data archives stored in distributed data servers as well as data analysis environment. For this purpose, it is important to establish a framework for access to remote servers, including remote procedure calls (RPCs)(More)
Currently two query languages are defined as standards for the Virtual Observatory (VO). Astronomical Data Query Language (ADQL) is used for catalog data query and Simple Image Access Protocol (SIAP) is for image data query. As a result, when we query each data service, we need to know in advance which language is supported and then construct a query(More)
Modern classification and clustering techniques analyze collections of objects that are described by a set of useful features or parameters. Clustering methods group the objects in that feature space to identify distinct, well separated subsets of the data set. However, real observational data may contain missing values for some features. A " shape "(More)
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