ADEC Interoperability Technical Working Group Report

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ADEC Interoperability Technical Working Group
Report
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Membership

• IRSA Bruce Berriman, John Goode
• ADC Kirk Borne, Brian Thomas
• CXC Arnold Rots
• NED Joe Mazzerella
• ADS Guenther Eichhorn
• MAST Tim Kimball
• HEASARC Tom McGlynn

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Charter

• Goal
• The top level goal is to provide seamless (one
  stop shopping) access to all the NASA
  astrophysics catalog and data services,
  irrespective of where the information is located.
• Charter Requirements
• All services will be accessible via standard
  protocols
• Access will be via the existing user interfaces
• Results will appear consistent with the interface
  that initiated the request
• Attribution of data to original site will be
  clearly stated

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Current Interoperating Services

• Many interoperating services are already in place
  at ADEC sites. E.g.,
• ADC links to HEASARC, IRSA and MAST archives
• ADS links to all datasets associated with a given
  bibcode.
• HEASARC links to CXC and MAST data and provides
  access to all VizieR tables.
• IRSA suite of remotely accessible catalog and
  data services
• MAST provides transparent access to HEASARC ROSAT
  and EUVE archives
• NED links to multiple ADEC/non-ADEC data sources
  for many objects. NED name resolver used many
  places.
• Astrobrowse services at CXC, MAST and HEASARC.
• No general framework for interoperations
• Limited capabilities
• Incompleteness/inconsistency
• Resource discovery is difficult
• Fragile links

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Summary of Activities

• Telecons
• January 18, 2002
• February 8, 2002
• Strawman design implementations
• Temporary Web site
• heasarc.gsfc.nasa.gov/itwg

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Areas of Agreement

• No generic mandates on user interfaces
• Each site uses resources developed in this effort
  to present information appropriate to its users.
• Layered approach to implementation
• Stage 1 Links to data products and services
• Stage 2 Seamless services
• Stage 3 ??
• Standardized publication of services
• Monitoring of VO activities

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Technical Issues

• What kinds of links should be made?
• What do we link to?
• Home page, service forms, availability summaries,
  queries, data products
• How do we mediate links?
• Metadata or tables

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Technical Issues

• How are links/services published?
• Machine versus human readable
• Dynamic database or static pages
• Syntax/standard to be used
• How frequently updated
• How is metadata about link included

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Technical Issues

• What is the vocabulary of linking?
• Linking by characteristic
• Links by position, time, object name
• Other fields (exposure, observer, ...)
• Table links, e.g., bibcode joins
• Metadata vocabulary
• Image/spectra
• resolution,
• Where do we get metadata information from?

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Technical Issues

• Formats for metadata and queries
• Usefulness of existing formats
• Usefulness of emerging standards
• Relationship to non ADEC institutions and efforts
  (CDS, VO)

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Phase 1 Plan

• Develop vocabulary for description of data center
  services (including access to data products).
• Establish desired ancillary metadata for
  services.
• Agree on protocol for publication of description
  of services.
• Publish descriptions of services in agreed
  protocol.
• Include links to described services/data in user
  interfaces.

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Develop Linkage Vocabulary

• How do we link?
• Develop use cases
• Describe current services
• Name and provenance of the resource
• How is the resource parametrized?
• Position, time, name, bibcode,
• How is the resource accessed?
• What is the format of the result?

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Establish Ancillary Metadata

• Why do we link?
• Type of information returned
• Product summary, catalog, image, spectra, home
  page,
• Wavelength regime
• Optional metadata
• Resolution, epoch range, volume estimators,
  desirability, ...
• Dependencies/linkages to other services

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Publication Protocol

• Answer how and why questions
• May use static product descriptor web pages at
  each site
• Fixed location for each site
• TBD XML? Format
• Role of GLU -- if any.
• Transition to UDDI/WSDL later?

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Publish Service Descriptions

• Multiple levels of description
• Site
• Data availability summaries
• service data entry
• service results
• data products.
• Most popular services first

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Integrate into user interfaces

• Site-based requirements
• Not all services may be appropriate even when
  they are in principal queryable.
• Review by ADEC

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Schedule Issues

• Dependent on resources allocated
• Effort uncertain but anticipated at a few
  person-months per institution
• Risk of impact on other activities
• Coordination of diffuse resources is difficult

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Schedule for Phase 1

• Six months to one year
• Development of metadata
• Initial vocabulary and ancillary metadata design
• Agreement on publication format
• Publication of services
• Publication of popular services
• Updates to vocabulary and ancillary metadata
• Integration within existing interfaces
• Integration within user interfaces
• Additional service descriptions

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Phase 2 ideas

• More seamless integration of systems.
• Use of remote services as database servers.
• Adoption of common machine readable format for
  results.
• Coordination with VO activities
• Use of Web as distributed file system for data
  products

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ClassX Classifying the High Energy Sky

• Two year NASA AISR program to develop science
  prototype for Virtual Observatory.
• Collaboration with ST ScI and CDS.
• Classify high energy sources
• Discover and collect data on sources from
  existing services
• Collate information into coherent dossiers.
• Use information to classify sources.
• Explore discovery, integration and metadata
  issues for VO.
• Science goals Samples of AGNs, early evolution
  of stars, analysis of XMM fields, ...

A SkyView ROSAT field around TY Pyx showing the
numerous serendipitous -- and largely
unclassified -- WGACAT sources in that field.