SVAC Prototype Database 

Ashmi  Ashokkumar Chokshi' , Jian Zhong,  Xin Chen ,

 Dylan ThurstonEduardo do Couto e Silva 

Last update October 22, 2004

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Check our new prototype and the  old in case you like history


The primary calibration database is maintained by the Science Analysis Software (SAS) group since the reconstruction programs need to read in the calibration constants for the various detectors. In the current prototype, the SVAC database will extract, via scripts, data  from the SAS database and populated tables of  the SVAC database, which  are designed to allow trend analysis with a pre-defined query system using a web interface. 

SVAC - Requirements

Allowing users to access data from the results GLAST calibration tasks and also allow them to perform trend analysis on these data. To be made accessible via Internet/intranet.

How the system will work

        As shown in Fig.1, our web pages will reside on the NT server. Users will access these web pages to view the data in various forms (histograms, tables etc.)

        Our data is on the Unix server, and we use Java Servlets to access the raw data and process it.

        Thus, the web page will invoke a servlet on the Unix machine, and this servlet will run inside the servlet container (in our case, in Tomcat).

Note: Tomcat is a server plugin that creates an environment for servlet execution. Thus, it is a servlet container or engine. The processed results will be sent back to the invoking HTML/ASP/other web page, which then outputs the results to the client (browser) in the  required format.


Fig1: System description

What has been done so far:

        I have been using parts of JAS (Java Analysis Studio) to implement the functionality.

        I extended the parts of JAS that relate to histogramming and XY-plots to work with database data. So now, it is possible to extract data dynamically from the database and use it to make basic histograms and XY plots. These are then output to a web page by the servlets.

        The user can  specify query  parameters via a form.

        A skeleton database is in place for present use.

Ongoing work:

        Calculating and displaying statistics with the plots.

        Presentation and arrangement of dynamically generated graphs on the web page. 

On my agenda:

        Allow more detailed query specification by user.

        Suggest database design to optimize performance.

Possible problem areas:

        Database design that is different from what would be optimal for the type of data access we require.

        JAS documentation is not detailed. (But Tony Johnson has been very helpful  in this regard).

        Manipulating arrangement and presentation of graphs is tedious GUI work.