VO-DAS Chenzhou CUI Chao LIU, Haijun TIAN, Yang YANG, etc National Astronomical Observatories, CAS.
-
Upload
jaiden-thornock -
Category
Documents
-
view
229 -
download
0
Transcript of VO-DAS Chenzhou CUI Chao LIU, Haijun TIAN, Yang YANG, etc National Astronomical Observatories, CAS.
VO-DAS
Chenzhou CUIChao LIU, Haijun TIAN, Yang YANG,
etc
National Astronomical Observatories, CAS
VO Data Access Service (VO-DAS)
An OGSA-DAI based service system to provide unified access to astronomy data, including catalogs, images and spectra.
Goals of VO-DAS Supporting high volume data query Interlinking distributed and heterogeneous archives
• catalogs, images, spectrums Providing a software that works for astronomersworks for astronomers
First Science Paper from China-VO
Candidate Milky Way satellites in the Galactic halo ( Liu et al., 2008, A&A)
SDSS DR5 photometric data were searched for new Milky Way companions or substructures in the Galactic halo.
Data analysis procedures were based on the VO-DAS. Five candidates are identified as over-dense faint stellar sources that
have color-magnitude diagrams similar to those of known globular clusters, or dwarf spherical galaxies.
Predicted Features
Goals: Uniform access to heterogeneous distributed datasets, bulk of data support
Functions Catalog, image, and spectrum support Dataset encapsulating and registry Data discovery Metadata description Jointed query on heterogeneous databases Bulk of data transfer support Sync and async queries Query status tracer ADQL support
Architecture Components
VO-DAS server DataNode Clients Registry Data storage
Technical Highlights
OGSA-DAI based data nodeAsynchronous query and cross match on
distributed databasesExtended ADQL, supporting catalog, image
and spectrum at the same time
Async Query Query segmented into sub-
queries Queries assigned to specific
DataNodes Query results transfer among
DataNodes Final results sent to data storage
service (VOSpace, FTP, etc) VO-DAS server supervises the
whole process No data exchange between
DataNode and VO-DAS server
Extended ADQL
SELECT s.ra, s.dec, s.g-s.i gi, s.i FROM SDSSDR5:star s WHERE s.ra>=120 AND s.ra<=270 AND s.dec>=25 AND s.dec<=70 AND s.i>=19 AND s.i<=22 AND s.g-s.i>=0 AND s.g-s.i<=1
SELECT f.Access_reference FROM SDSSDR6:specfile f, SDSSDR6:sspParams s WHERE s.specID=f.specID AND f.SNR>10 AND s.alphafea<=0.2 AND s.feha>-0.9
VO-DAS Clients GUI CLI WebBrowser MATLAB Client
Interoperability
PLASTIC, SAMP
MATLAB based DM environments
AstroboxAstrobox
AstroBox A plug-in package for MATLAB to
provide an astronomical data mining application service, supporting VO protocols and tools.
A high-level data analysis environment supporting: PLASTIC VOTable Local DB VO-DAS client Astronomical algorithms
VO-DAS
MATLAB VO-DAS Client
MA
TL
AB
D
ata
base
Too
lbox
Local DBJa
vaLi
brar
ies
VO
Tab
les
PLASTIC
VO Tools(Aladin, TOPCAT)
AstroBoxAstroBox
MATLAB based DM environments (cont.)
Science case:Sub-structure study for the Galaxy
Methodology
Density count in area (ra=120~270deg, dec=25~70deg) where i=19~22 and g-i=0~1 in the SDSS DR5 (bin=0.2x0.2deg)
Obtained 524 over density areaCalculate CMD for each areaIdentify these CMDs by hands
Results
Work done by VO-DAS 70 millions records queried from
SDSS DR7 database Calculate CMD for each over
density area
Other tasks done by MATLAB
Lessons learned
Grid and SOAP based data access solution is feasible
Too complex to control
Low performance
Current: RESTful TAP DAS
Collaboration Environment
CSCW(computer supported cooperative work)
e-ScienceVO
Collaboration Enviroments
LAMOST DBs
Project Scientists
ObservationDB
SciDB (internal)
SciDB (public)
Scientific WGs
Papers
Public Users
Data Processing
Research Projects