ODW13 Draft URI-strategy for NL PSI


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Presentation with notes of considerations of the technical aspects of a URI-strategy for Public Sector Information in The Netherlands.

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  • This is a concept of the technical choices to be made for a national URI strategy for Public Sector Information in the Netherlads. It’s just a draft of ideas to be presented at Open Data on the Web 2013 (ODW13) to get feedback. Hans Overbeek works for the Dutch Ministery for the Interior and Kingdom Relations. Thijs Brentjens works for Geonovum, a Dutch public body for Geo standards and application of the Inspire directive.
  • Important sources of knowledge and information when we made this concept for the national URI strategy: The Inspire directive that prescribed a national strategy for URIs for geo-information with recommendation to connect this geo strategy to a national generic strategy. Designing URI sets for the UK Public Sector. A recommendation by the UK government, front runners in publishing Linked Open Government Data. 10 Rules for persistent URIs, a comprehensive report by the EU about comparable initiatives and a valuable overview of the latest best pracrtices.
  • The Linked Data cloud is huge and succesful, without any URI strategy, so why would we need a National Stratgy for URI’s for government information?
  • It is no longer possible to make a complete map like this one. There are many government registers with authentic data. How to
  • A URI strategy is supposed to facilitate re-use of authentic data and interoperability standards. A national strategy alines initiatives and helps custodians of these authentic data sets (registers) and interoperability standards to develop compatible components for a linked data eco system
  • We distinguish three categories of information sources: Standards, Registers and ‘ ordinary ’ Applications and three categories of concepts in an information source: terms in an abstract Model, Reference objects and ‘ ordinary ’ Data. The size of a cell indicates the importance of the concept category in that category of information source: The main function of a Standard usually is to define an abstract Model, Registers are usually set up to keep administration of Reference Objects and ‘ ordinary ’ Applications are usually just have a purpose to collect Data for a specific goal. Of course, a Register and an Application also might have an abstract Model of their own and some Standards provide lists of Reference values and Applications can have Reference tables too and Standards and Registers might contain ‘ ordinary ’ Data, for instance about provenance.
  • Concepts (classes and properties), which are defined in models, are used to classify reference objects and data. Registers and other applications re-use concepts defined by standards.
  • Reference objects, defined by standards (think of controled vocabularies) and managed in authentic registers are used in ‘ ordinary ’ applications.
  • The URI-strategy aims at Models and reference objects of Standards and Authentic Registers
  • When thinking about choosing identifiers for real life things, we realized that things in real life never have a suitable identifier by themselves. As soon as we try to mint identifiers for real life things we need to register them. Identifiers only exist in registers! In this sense standards have to be considered as particular registers.
  • We considered several options, but ended up at the same patern as suggested by data.gov.uk and ISA.
  • We decided for {register}.data.gov.nl/. To use {sector} would be nice from a semantic point of view, but there are issues: - How to find a custodian for each sector? How to decide to place an object type under which sector? And without a patern we would loose the recognizable patern of data.gov.nl.
  • URI’s for terms in the model follow a slightly different patern with a hash-URI. A model usually is not too big. Advantage is to always find the entire model if you request for one term.
  • ODW13 Draft URI-strategy for NL PSI

    1. 1. Concept URI Strategyfor the NL Public SectorDRAFT version – Q1 2013Hans Overbeek @hoverbeeThijs Brentjens @thijsbrentjens
    2. 2. Starting pointsDesigning URI Sets forthe UK Public Sector.D7.1.3 - Study on persistent URIs, with identification ofbest practices and recommendations on the topic for theMSs and the EC
    3. 3. URI-strategy: why?
    4. 4. URI-strategy: why?TrustIntuitionRecognizability
    5. 5. Goal of URI-strategy for PSIWhy is this important for Government information?•Indication that URI comes from trustworthy, authentic register.•Re-use of existing registers with authentic data•Re-use of existing harmonisation models•Making this ituitive, easy, attractiveInsight
    6. 6. Goal of URI-strategyModelDataReference-objectsa1b2c3c2c1a3a2b3b1Standard ApplicationAuthenticRegisterInsight
    7. 7. Re-use of Ontology TermsModelDataReference-objectsa1b2c3c2c1a3a2b3b1Standard ApplicationAuthenticRegisterInsight
    8. 8. Re-use of Reference ObjectsModelDataReference-objectsa1b2c3c2c1a3a2b3b1Standard ApplicationAuthenticRegisterInsight
    9. 9. Re-use of Reference ObjectsModelDataReference-objectsa1b2c3c2c1a3a2b3b1Standard ApplicationAuthenticRegisterInsighta3
    10. 10. No Register?No Identifier!Insight
    11. 11. URI paternTo encourage adoption:•KISS (human readable, short)•Trustworthy•Intuitive•Persistenthttp://{domain}/{type}/{concept}/{reference}Conclusion
    12. 12. http://{domain}/{type}/{concept}/{reference}{domain} identifies the register in a persistentwaySo idealy: {register}.data.gov.nl/• {register}: No register, no identifier!• ‘data.gov.nl’: recognisable, trustworthy, persistent.or: {sector}.data.gov.nl/{register} ?• Which part DNS-adressable?or {yourdomain}/{yourpath} ?Ques-tions
    13. 13. http://{domain}/{type}/{concept}/{reference}{domain} = {register}.data.gov.nl/What infrastructure is needed?• A register of registers• Register name• Register mnemonic• Register resolver• Register administrator• How will apps use the resolvers and how frequently?Ques-tions
    14. 14. http://{domain}/{type}/{concept}/{reference}{type}• ‘id’: identifier of real life object *in a register*• ‘doc’: documentation about the real life object bythis register• ‘def’:Wait, let me…
    15. 15. http://{domain}/{type}#{concept}{type}• ‘def’: definition of a term in an ontology• Hash-URI• URI of model: http://{domain}/defUK-strategy recommends slash URI’s forvocabulary terms. Why?Sometimes no clear distinction between modeland contentQues-tions
    16. 16. http://{domain}/{type}/{concept}/{reference}{concept}• The {concept} is ‘just a string’ NOT the formalclassification of the identified resource. It has nosemantic meaning, just comes in handy for thehuman reader and helps to make uniquereferences• Singular• Avoid all other characters than a-z, A-Z, 0-9• CamelCase or lowercase? Ques-tions
    17. 17. To identify concepts:• Classes, properties and skos:concepts• Hash-URI always retuns complete ontologyhttp://{domein}/def• Use UpperCamelCase for classes andconcepts, lowerCamelCase for propertieshttp://{domain}/def#{concept}
    18. 18. http://{domain}/{type}/{concept}/{reference}{reference}Key of the resource within the register. URI-strategyleaves lot of freedom to the registrar: many differentrequirementsSome recommendations:•Try to avoid special characters•Use W3CDTF for versions•Avoid information bearing keys