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: http://www.adass.org/adass/proceedings/adass00/P1-09/
Дата изменения: Tue May 29 19:37:07 2001 Дата индексирования: Tue Oct 2 04:46:11 2012 Кодировка: Поисковые слова: п п п п п п п п п п п п п п п п п п п п п п п п п |
Huairou Solar Observing Station's (HSOS) magnetograph can simultaneously measure the solar 2-D magnetic field and velocity field with different spectral lines. The photospheric vector magnetograms and dopplergrams, chromospheric longitudinal magnetograms and dopplergrams, and corresponding filtergrams can be obtained by this system. So far, 13 years of observations have been obtained.
Because of the international character of astronomy, we are planning to develop software that is independent of the archive architecture and which provides users with Web access capabilities.
Given the large amount of data, and that the data is not only plain text but also image file, visual file, we select a relational database--MySQL--to build the database management system, and use PHP to build the database engine and user query interface.
The final system is expected to allow users to get good response time and easy browsing of the HSOS on-line database by the means of a Web-based user interface, display results graphically, and save them locally for further analysis.
In Figure 1, we give an overview of the architecture of the system:
At present, only the data which are currently being used or built in the HSOS database project are foreseen to be included in the database. They are: photospheric longitudinal magnetic field data, photospheric filtergram image data and photospheric transverse magnetic field. Other data, for example, chromospheric longitudinal magnetic field, filtergram image, longitudinal velocity field data, etc., may be added in the future depending on users' requirements. Users can learn more about HSOS data through reading the the on-line README file.
All data in the collection are described in a metadata structure we call the metadata table. All applications will access the database through the table, so that they will work independently of any data-specific structure. Using a table will also simplify the addition of new data to the collection. Metadata access has been developed in the PHP language.
We are following the recent efforts directed at giving users direct access to HSOS database through the HSOS Web site. We will give users integrated access to world-wide distributed astronomical data collections. Our efforts will be directed to providing open access to the system by means of standard interfaces. In our view, this is the most effective way to maximize our system's utilization.
We are currently prototyping simple WWW-based clients able to submit queries to the on-line system. These clients are implemented in PHP. In this way, users are not required to install special client software and more interactivity is possible at the user workstation level. After this prototyping phase, we plan to design and build more sophisticated, intuitive interfaces to allow users to submit complete queries to the database, possibly in a graphical way.
PHP has the following useful features:
The critical factors for a database management system are:
PHP and MySQL work with each other very well. Both PHP and MySQL are open source software. In combination with our Linux operating system, they form a ideal network database environment.