26 October 2004ADASS Pasadena1 Publishing and Resource Discovery with Registries Ray Plante T HE US N ATIONAL V IRTUAL O BSERVATORY Kevin Benson Sebastien Derriere Pierre Fernique Matthew Graham Gretchen Greene Bob Hanisch Paul Harrison Martin Hill Jeongin Lee Gerard Lemson Tony Linde Tom McGlynn Wil O’Mullane Keith Noddle Ramon Williamson Visit the NVO Demo Booth

26 October 2004ADASS Pasadena2 Summary (2003) We built a working prototype registry system to support an end-user VO service –Distributed Publishing and Searchable components –Encoded descriptions using emerging VO XML standard schemas –OAI Harvesting Standard deployed easily –Used to discover Cone Search and SIA services What’s next: Interoperable registries IVOA-wide –Stablize XML metadata standard –Standardize registry interfaces

26 October 2004ADASS Pasadena3 Summary (2004) We built a working production registry system to support an end-user VO services –DataScope: discovers Cone Search, Simple Image Access services –OpenSkyQuery Portal: discovers OpenSkyNodes What’s next: Interoperable registries IVOA-wide –Stabilize XML metadata standard –Standardize registry interfaces => IVOA: Frozen working draft standard for January ’05 releases

26 October 2004ADASS Pasadena4 Registries 2004 Review of Registry architecture Resource Metadata Model IVOA Registry Interface Standard –Harvesting –Searching The NVO Publishing Process Searching for Resources Curation Issues

26 October 2004ADASS Pasadena5 The role of Resource Registries Used to discover and locate resources—data and services—that can be used in a VO application Resource: anything that is describable and identifiable. –Besides data and services: organizations, projects, software, … –Presently concerned with simple set of resource types Registry: a list of resource descriptions –Expressed as structured metadata to enable automated processing and searching

26 October 2004ADASS Pasadena6 Selected Requirements Allow user to select resources that are likely to pertain to a scientific question Select resources based on characteristics… –Type of resource: catalogs, image archives, EPO, services –Coverage in space, time, and frequency –Where data comes from, who curates it Dynamic: resources will come and go Distributed: Should not depend on a single point of failure or single view of the VO. Preserve the data providers’ control over their data –Curators control what gets registered, content, updates –Allow integration with existing resource management Allow extension to new types of resources

26 October 2004ADASS Pasadena7 IVOA Registry Working Group (RWG) IVOA = International Virtual Observatory Alliance Common, global approach to registries Towards a standard framework –Registry Model –Resource Identifiers –Metadata schemas –Registry Interface Distributed model for registries

26 October 2004ADASS Pasadena8 Local Publishing Registry Local Searchable Registry Full Searchable Registry Local Publishing Registry Full Searchable Registry Data Centers VO Projects Specialized Portals & Services Registry Model

26 October 2004ADASS Pasadena9 Local Publishing Registry Local Searchable Registry Full Searchable Registry Local Publishing Registry Full Searchable Registry Data Centers VO Projects Specialized Portals & Services Registry Model harvest (pull)

26 October 2004ADASS Pasadena10 Local Publishing Registry Local Searchable Registry Full Searchable Registry Local Publishing Registry Full Searchable Registry Data Centers VO Projects Specialized Portals & Services Registry Model harvest (pull) replicate

26 October 2004ADASS Pasadena11 Local Publishing Registry Local Searchable Registry Full Searchable Registry Local Publishing Registry Full Searchable Registry Data Centers VO Projects Specialized Portals & Services Registry Model harvest (pull) replicate selective harvesting

26 October 2004ADASS Pasadena12 Local Publishing Registry Local Searchable Registry Full Searchable Registry Local Publishing Registry Full Searchable Registry Data Centers VO Projects Specialized Portals & Services Client Applications search queries Registry Model

26 October 2004ADASS Pasadena13 Local Publishing Registry Local Searchable Registry Full Searchable Registry Local Publishing Registry Full Searchable Registry Data Centers VO Projects Specialized Portals & Services Client Applications search queries Registry Model

26 October 2004ADASS Pasadena14 Local Publishing Registry Local Searchable Registry Full Searchable Registry Local Publishing Registry Full Searchable Registry Data Centers VO Projects Specialized Portals & Services Client Applications search queries Registry Model

26 October 2004ADASS Pasadena15 Local Publishing Registry Full Searchable Registry Local Publishing Registry Caltech JHU/STScI harvest (pull) DataScope search for services Registries in Use: DataScope NCSA DS

26 October 2004ADASS Pasadena16 Local Publishing Registry Local Publishing Registry Local Publishing Registry Full Searchable Registry Local Publishing Registry Caltech JHU/STScI harvest (pull) DataScope search for services NCSA DS HEASARC CDS Full Searchable Registry AstroGrid Registries in Use: DataScope

26 October 2004ADASS Pasadena17 Cone Search Service Cone Search Service Simple Image Access Simple Image Access Full Searchable Registry JHU/STScI search for services Cone Search Service Simple Image Access Data Providers DataScope DS Full Searchable Registry AstroGrid Local Publishing Registry Local Publishing Registry Local Publishing Registry Local Publishing Registry Caltech harvest (pull) NCSA HEASARC CDS Registries in Use: DataScope

26 October 2004ADASS Pasadena18 Registries in Use Registries in the NVO are currently operating and functional –DataScope: discovers Cone Search, Simple Image Access (SIA) services –OpenSkyQuery Portal: discovers OpenSkyNodes –CDS Aladin/GLU: (Pierre Fernique) harvests Cone Search and SIA services converts them into GLU dictionary records Accessible directly by the Aladin image and catalog viewer AstroGrid Registry foundation for building workflows –Portal uses descriptions to stitch services together –(Previous talk by Keith Noddle) Cross-project harvesting –NVO, AstroGrid, AVO (Vizier, GLU) Registries are at the leading edge of VO development

26 October 2004ADASS Pasadena19 Resource Metadata Model IVOA Recommendation: Resource Metadata

26 October 2004ADASS Pasadena20 Resource Metadata Model IVOA Recommendation: Resource Metadata Resource OrganisationService IVOA Working Draft: VOResource as XML Core Metadata

26 October 2004ADASS Pasadena21 Resource Metadata Model IVOA Recommendation: Resource Metadata Resource OrganisationAuthority Registry Service IVOA Working Draft: VOResource VORegistry DataCollection SkyService TabularSkyService VODataService as XML

26 October 2004ADASS Pasadena22 Resource Metadata Model IVOA Recommendation: Resource Metadata Resource OrganisationAuthority Registry Service IVOA Working Draft: VOResource VORegistry DataCollection SkyService TabularSkyService VODataService SimpleImageAccess SIA ConeSearch as XML

26 October 2004ADASS Pasadena23 Resource Metadata Model IVOA Recommendation: Resource Metadata Resource OrganisationAuthority Registry Service IVOA Working Draft: VOResource VORegistry DataCollection SkyService TabularSkyService VODataService SimpleImageAccess SIA ConeSearch CEAApplication CEAService VOCEA as XML

26 October 2004ADASS Pasadena24 IVOA Working Draft: Registry Interface (RI) Standard Kevin Benson (AstroGrid), Editor Harvesting Delivering resource descriptions from publishers to searchable registries –Adoption of Open Archives Initiative (OAI) standard: Protocol for Metadata Harvesting –RI defines application of OAI to VO resource records Plug in VOResource as metadata format –Optional SOAP version to augment HTTP Get standard Searching –Returns XML VOResource records –Keyword search –Advanced search Uses the Astronomical Dataset Query Language (ADQL) Refer to metadata items via a simplified XPath –Easily mapped to either SQL for an RDBMS implementation, XQuery for an XML DB implementation

26 October 2004ADASS Pasadena25 Publishing to the NVO Resources are published if one can use VO facilities to find them. Multiple layers of publishing –Starts with registry description of resource –Data Access Services Incremental exposure for incremental effort Who are you? How you publish depends on what you want to publish. –An individual with a small data collection –An archive center –Someone with a cool service Extinction Correction Service –Developed by C. Miller, K. S. Krughoff –In one day of the NVO Summer School using VO tools

26 October 2004ADASS Pasadena26 Small collections: VO-ready Repositories Repositories that allow users to deposit data to share with community –Guarantee long-term storage, availability Automatic support for VO publishing mechanisms –Entries into NVO Registry –Support for standard services: Cone Search, SIA, SSA, SkyNode Currently available Repositories –Images: NCSA Astronomy Digital Image Library –Spectra: Spectrum Services for the VO More public repositories are expected to emerge Check NVO website ( for latesthttp://us-vo.org/

26 October 2004ADASS Pasadena27 Persistent Archives: Tools for Federation Registering your resources with a public VO publishing registry Choose resource type Edit Form STScI Registry NCSA Registry

26 October 2004ADASS Pasadena28 Persistent Archives: Tools for Federation Registering your resources with a VO publishing registry –Enter description into registration form at one of the available NVO registries: STScI/JHU Registry: NCSA Registration Portal: Caltech Carnivore: –If you have a large number of resources to register, you can run your own registry on your own site NCSA VORegistry-in-a-Box Caltech Carnivore:

26 October 2004ADASS Pasadena29 What can/should you register? –Should: your Organization Declares yourself as a publisher with an ID –Should: your Collection Users at least know how to access it via a Browser –Can: your existing services Browser-based services: e.g. search page Traditional CGI services Web Services The next level… Implement and register one or more standard services –Cone Search –Simple Image Access –SkyNode* –Simple Spectral Access* *standard still in development NVO Summer School Software package: server-side templates and toolkits Persistent Archives: Tools for Federation

26 October 2004ADASS Pasadena30 Cool Services: Integrating with the VO 1.Register your service at a registry 2.Integrate support for standard VO formats, schemas FITS and VOTable  Enable integration with existing tools & visualizers Standard Data Model schemas (emerging) VOResource, Space-time Coordinates, Spectra  Enable integration with other services using these models 3.Implement Standard Support Interface a standard in development for: Self-description, tracking health and usage

26 October 2004ADASS Pasadena31 Searching the Registry Use a searchable registry to find data and services –NVO has two searchable registries available: STScI/JHU Registry: Caltech Carnivore: Two types of searches: –Simple keyword-based search –Advanced search STScI/JHU: SQL-based Caltech: XQuery-based Currently working on user-oriented improvements to interactive interface G. Greene & W. STScI –Help with advanced searches –Improved organization of returned results

26 October 2004ADASS Pasadena32 Accessing the Registry from Applications Custom Web Service Interfaces available –keyword and advanced search functions –Currently used by DataScope and SkyPortal IVOA Standard Web Service interface –Full support targeted for January 2005 roll-out –Beta support available from Caltech Carnivore Available Java client software –Currently available via NVO Summer School software distribution Zip file: HowTos: –Includes: Client library for IVOA Standard search interface Sample client code for both custom and standard interfaces

26 October 2004ADASS Pasadena33 Curation Issues NVO Registries now contain over 3000 records  Lots of problematic metadata: –Missing information, incorrect usage, truncated values –Duplicates, deprecated records, missing resources –Broken/non-compliant services People need to assume responsibility for curation –Software can help, but is not sufficient –Role of Registry administrator?

26 October 2004ADASS Pasadena34 A practical approach to Curation Proposal: “VerificationLevel” tag attached to resource descriptions by a registry curator –3 levels: Unverified Verified by software Verified by human curator –Tag exposed to users/apps: e.g. select only highly verified resources –Tag is specific to a registry; can by overridden when harvested by another registry. Software verification –NCSA: building a suite of software verifiers –Can be incorporated directly into registries Either locally or by calling a remote web service –First example: Cone Search Verifier

26 October 2004ADASS Pasadena35 Summary 2004 NVO is operating production registries –serving end-user applications –greater emphasis on user interfaces –registry searches easily integrated into applications –Full release of latest improvements by January 2005 Interoperable exchange between IVOA registries Extensible Resource Metadata model IVOA Registry Interface Standard is emerging What’s next: shift from development to curation Finalize RI standard Address curation issues No talk on registries next year