Web

1
Web Grid Services Track Summary
Coordinators Brian Wilson, Paul Davis
Contributors Mike Smorul, Gary Jackson, Rudy
Husar,Heather Weir, Michael Burnett, Yonsook
Enloe, and many others
2
Promo

• Well Answer These Provocative Questions
• Is SOAP the universal "glue" for distributed
  scientific data processing? The IT world seems
  to think so.
• Will Web and Grid services ever converge (as in
  OGSI and WSRF)? Yes.
• What exactly can one do with a Data Grid?
  Plenty.
• Can I really use the Globus Toolkit to find and
  use compute resources on the Grid? Yes.
• How do I do distributed computing and still sleep
  at night? (i.e., with security, authentication,
  authorization, single sign-on, reliability,
  traceability, data provenance, load balancing,
  etc.)

Carbon Cycle
3
WS Summary

• SOAP, WS, and Service Collaborations
• Significant interest in and use of Simple Object
  Access Protocol (SOAP) for accessing services and
  WSDL for describing them.
• Significant work has already been done on
  creating a taxonomy of services and a service
  registry.
• GCMD SERF documents services catalog
• ECHO service taxonomy UDDI registry
• Promote service collaborations (service chains)
  within the Federation by developing pilot
  projects.
• WSRF and WS- Standards are still evolving.

4
WS Recommendations

• Use the GCMD SERF catalog for Federation service
  registry discovery.
• As opposed to creating an independent Federation
  survey of available services.
• Many ESIPs have already written SERF documents.
• Modify/add XML tags to the SERF document to
  support URL links to WSDL and XML schema docs.
• Promote the GCMD SERF Activity
• Have SERF Fest at the next ESIP Federation
  Meeting.
• Publish TOP 20 list of services discovered and
  called via the GCMD services catalog.
• Coordinators Comments/suggestions to Heather
  Weir at GCMD and/or Brian Wilson.

5
WS Recommendations

• Create a test bed for registry and discovery of
  Federation SOAP/WSDL services.
• ECHO will support a UDDI registry in v7.
• Mature our understanding of shared service
  descriptions.
• Promote interoperability and links between SERF
  documents, service taxonomies, and UDDI
  registries.
• Coordinator Michael Burnett.

6
WS Recommendations

• Start a Federation Service Collaboration
  Cluster to create a Federation Service-Oriented
  Architecture (SOA) built on contemporary Web
  Service technologies (SOAP/WSDL).
• Create service collaborations (chains) within the
  Federation.
• Develop a taxonomy of services (data discovery,
  query, access, etc.) for SOAP purposes
  (leveraging work by ECHO and others).
• Use the taxonomy to design a standard set of
  Federation SOAP service interfaces.
• Explore the problems of tying together
  independently developed services with varying
  interfaces (semantic mediation).
• Demonstrate interoperability between OpenDAP, OGC
  WMS/WCS and SOAP services.
• Organizer Brian Wilson.

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Grid Services Summary

• Data Grid
• Storage Resource Broker (SRB) is stable and
  usable.
• A SRB-based Federation Data Grid exists (3 site
  consortium led by U. Maryland)
• Globus also provides Data Grid services (MCS,
  RLS, RFT).
• Grid Services
• WS- Standards are still evolving.
• Globus Alliance Toolkit is evolving rapidly.
• Globus v2.4 in production use, but not WS based.
• Globus v3.2 works (OGSI spec.) but has been
  superseded.
• Globus v4 (WSRF spec.) is not available yet
  (beta, Mar 2005).
• Further technology exploration (testbed
  activity) will be required.

8
Grid Services Recommendations

• Expand participation in the SRB-based Federation
  Data Grid
• Write a white paper describing the benefits of
  joining the Fed. Data Grid (WHY-TO doc).
• Create a HOW-TO document for installing SRB and
  joining the Fed. Data Grid.
• Review and report back about advances in Globus
  services maturity (v4).
• Presentation, with a demo, at the next ESIP
  Federation Meeting.
• Coordinator Paul Davis.

9
Grid Services Recommendations

• Investigate WS Choreography / Grid Workflow
  technologies.
• One activity within the new Services
  Collaboration cluster.
• Join Grid Workflow activities discussions at
  Global Grid Forum (GGF) meetings.
• NASA Federation input to GGF world.
• Earth Science is a new application domain for GGF
  workflow efforts.
• Coordinators Brian Wilson, Yonsook Enloe.

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11
Data Query/Access Services

• Services Chain goes beyond simple data access
• Time Geolocation Query ? yielding data
  inventory
• Query on Quality Flags
• General Metadata Query ? catalog satisfying
  conditions
• Data Access - by object or granule ID and
  variable name
• Data Slicing - as in OpenDAP
• Data Subsetting by lat, lon, alt, time ranges
• Parameter Subsetting select only desired
  physical variables
• Data Reformatting choose output format as in
  WMS/WCS
• On-Demand Grid Computations grid diff in
  GraDS/DODS
• Variable Bundles external metadata from
  scientist
• Return Composite Data Objects
• 4DRectilinearGrid, 4DCurvilinearGrid (swath)
• XML Native Binary representations
• User Composites add custom object to data model
• Semantic Support
• Use generic variable names
• Reason about variables to be bundled

12
SciFlo Data Query/Access (SOAP) Services

• QueryByGeoLocation(startTime, endTime, lat, lon,
  timeTolerance, distanceTolerace, variable,
  metadataGroups)
• Returns granule IDs and geolocation info. for
  AIRS L2 swaths that intersect lat/lon point or
  are near enough.
• QueryByGeoRegion(startTime, endTime, lat/lon
  region, . . .)
• Returns granule IDs and geolocation info. for
  AIRS L2 swaths that intersect the lat/lon region
  or are near enough.
• QueryByMetadata(variable, ListOfConstraints,
  groups)
• Returns granule IDs and selected metadata for
  AIRS granules that satisfy the metadata
  constraint expression(min1 lt field1 lt max1
  and/or min2 lt field2 lt max2 . . .).
• FindDataById(IdList, UrlOptions)
• Given list of unique IDs, returns list of ftp,
  http, or DODS URLs pointing to the granules
  (files). Uses cache and redirection server.
• -- Other semantic interfaces possible

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SciFlo Data Query/Access (SOAP) Services

• GetMetadata(type, groups)
• Returns metadata describing scientific domain,
  dataset info, list of metadata fields, generic
  name translation table, location of XML schema
  documents, location of related ontologies
  (OWL/RDF), etc.
• GetHelp(type, groups)
• A SOAP service that itself returns help
  documentation describing the available SOAP
  services.
• --These Services Combined Can Support
• Data Catalog, General Query, Data Access, Generic
  Names,
• Data Discovery by Domain and Dataset Keywords
• Type checking via XML schemas
• Hooks to semantic web

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Data Discovery to Inventory Level

• SOAP Services just described provide
• Domain description Metadata
• Dataset Info. and Keywords
• Generic VariableName Lookup Table
• Query by Metadata or just Time GeoRegion
• Layer more semantics on top of these services
• Dataset Discovery by keyword search
• Bind in additional metadata provided by scientist
• Tie ontologies into keywords and
  genericVariableNames
• Semantic Inference AIRS and MODIS both provide
  atmosphericTemperature and cloudProperties.
  Hmmm. Compare them.
• XML/SOAP provides substrate possibilities only
  limited by ontology development.