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: http://www.adass.org/adass/proceedings/adass99/P3-06/
Дата изменения: Wed Oct 11 04:13:30 2000 Дата индексирования: Tue Oct 2 05:11:33 2012 Кодировка: Поисковые слова: п п п п п п п п п |
This paper presents the notification mechanism which uses a specially developed server and a number of database triggers. The client interface for data products exchange is also presented, as is the mechanism to generate parameters for a pipeline run and store their updated values as returned by the pipeline for subsequent retrieval at higher levels of processing. In addition, the mechanism for the public access of the data files and metadata via the Web is described.
Automatic processing (AP) uses the arc4gl client to make requests to the archive server for ingest and retrieval of data files. In addition, it utilizes the obspar program to extract ancillary data from database tables in the Sybase SQL server. Automatic processing has the capability to register with the AP notification server to be notified of events such as data arrivals or changes in an observation's status.
Observers and public users download Java applets from the Web server using a Web browser. Data browse and retrieve requests are made through applet buttons and are sent through the Gateway to the SQL server or to the archive server. Data is sent back to the applet for viewing or retrieval.
The arc4gl language used to make data requests is presented in the form ``keyword = value''. The server responds by executing an ingest, a browse, or a retrieve operation. Users must specify these operations along with other arc4gl keywords like filename, file type, level of processing, observation identifier (obsid), observation interval (obi), time range, etc. in order to correctly identify data products in the database and in the file storage area. If a file is ingested, pertinent archival information is extracted from the file and stored in the database by the archive server. This information is used for future browse and retrieve operations.
Included is an example of an arc4gl request for an observation that has an obsid, 1069. The user is requesting to browse the archive contents of level 1 event lists for the specified observation. The filename, file size, and the time it was archived is given back to the user.
arc4gl> operation=browse arc4gl> dataset=flight arc4gl> detector=acis arc4gl> level=1 arc4gl> obsid=1069 arc4gl> filetype=evt1 arc4gl> go Browsing... Filename FileSize(bytes) File_TimeStamp acisf01069_000N001_evt1.fits 14276160 9/5/1999 22:50:09 1 record(s) browsed Browse succeeded arc4gl>
Included is an excerpt of an obspar-generated parameter file for planned data for obsid, 1069.
CLI PROMPT: obspar -o1069
title,s,h,"",,,"Proposal title" observer,s,h,"DR. CAL",,,"Principal investigator" object,s,h,"LMC X-1",,,"Source name" obs_id,i,h,1069,,,"Observation id" obi_num,i,h,0,,,"Obi number" instrume,s,h,"ACIS",,,"Instrument" detector,s,h,"ACIS-S",,,"Focus detector" detnam,s,h,"ACIS-456789",,,"Detector" ra_pnt,r,h,84.914583,,,"Pointing RA" dec_pnt,r,h,-69.743611,,,"Pointing Dec" tstart,r,h,51711568.184000,,,"Observation start time" tstop,r,h,51713568.184000,,,"Observation end time"
Planned and scheduled observation data can be accessed by the OCAT browser applet and Chandra data files can be browsed and retrieved through the Search and Retrieve applet. Users set observation search criteria in the OCAT browser applet and submit the request. Observation records matching the criteria are returned for viewing. Data products for all observations or for a subset of these observations can then be selected and retrieved using the Search and Retrieve applet.
Chary, S., DuPrie, K., Harbo, P., Pak, K., & Zografou P. 1997, Search and Retrieval of the AXAF Data Archive on the Web using Java, in ASP Conf. Ser., Vol. 145, Astronomical Data Analysis Software and Systems VII, ed. R. Albrecht, R. N. Hook, & H. A. Bushouse (San Francisco: ASP)
Zografou, P., Chary, S., DuPrie, K., Harbo, P., & Pak, K. 1997, AXAF Science Center Data Archive for AXAF Ground Calibration, in ASP Conf. Ser., Vol. 145, Astronomical Data Analysis Software and Systems VII, ed. R. Albrecht, R. N. Hook, & H. A. Bushouse (San Francisco: ASP)