Data files and their interdependences: a data base for the tokamak fusion experiment ASDEX Upgrade

• Published in: Fusion engineering and design 1999, Vol.43 (3), p.451-456
• Main Authors: Maier, J., Pacco Düchs, M.G., Precht, I., Tichmann, C., Hertweck, F.
• Format: Article
• Language: English
• Subjects: Applied sciences; ASDEX-Upgrade data; Consistency problems; Controled nuclear fusion plants; Database systems; Dependence data base; Energy; Energy. Thermal use of fuels; Exact sciences and technology; File organization; Installations for energy generation and conversion: thermal and electrical energy; Online systems; Thermonuclear reactions
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/S0920-3796(98)00417-7

Fusion experiments produce large amounts of raw data which must be evaluated. From these data the diagnosticians derive ‘processed’ data files in increasing ‘levels’ of evaluation. The processed data files can be modified several times due, for example, to recalibration or correction of errors. The re-computation of files and the invalidation of the previous versions cause consistency problems. The dependence data base (DDB) addresses this problem, which is essential for the users of experimental data. The DDB keeps track of the mutual dependences between data files. Any re-computation creates a new ‘valid’ version of a file and renders the previous version and all files derived from it ‘invalid’. Previous versions are kept in the file system and a file history can be retrieved. The DDB works on-line, so that it is always up-to-date. The structure of the DDB and its application to ASDEX-Upgrade data are described.