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Ivan Herman W3C. (2)  Current RDF has been published in 2004  Significant deployment since then ◦ implementation experiences ◦ users’ experiences 

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Presentation on theme: "Ivan Herman W3C. (2)  Current RDF has been published in 2004  Significant deployment since then ◦ implementation experiences ◦ users’ experiences "— Presentation transcript:

1 Ivan Herman W3C

2 (2)  Current RDF has been published in 2004  Significant deployment since then ◦ implementation experiences ◦ users’ experiences  Some cracks, missing functionalities, etc, came to the fore  There are significant communities that have not picked up RDF ◦ e.g., Web Developers

3 (3)  Shall we ◦ live with those issues and go on with our lives? ◦ dump it and start all over again from scratch? ◦ do some minimal changes?

4 (4)  W3C organized a Workshop in June 2010 ◦ 32 submissions, 28 accepted, 18 were presented at the workshop ◦ 2 busy days at Stanford (courtesy of NCBO)

5 (5) 5

6 (6)  Try to answer the question: live with it, redo it, mend it… ◦ if something has to be changed, what is it and with what priority?  Give a list of possible work items, with priorities

7 (7)  Yes, it is probably o.k. to touch some issues  But we have to be very careful not to send the wrong signal to adopters, tool providers, etc.  I.e.: keep the changes to the minimum

8 (8)

9 (9)  Workshop report published: ◦  W3C Team began working on chartering  …but felt the larger community should be asked  A questionnaire was published in August 2010 ◦  And, of course, lots of discussion on various fora

10 (10)  I will list the major items that came up during the discussions ◦ mostly the Workshop+Questionnaire, plus some others  I will list them in the order of ◦ may end up in the RDF Working Group Charter ◦ should be done but not clear yet where and how ◦ postpone it for now

11 (11)

12 (12)  There are some errata that have to be taken care of ◦ exact relationship to IRI-s ◦ more flexible references to XML versions ◦ etc  Not worth discussing them here

13 (13)  A.k.a. “named graphs”, “quoted graphs”, “knowledge bases”  Is on the top of all priority lists…  But the semantics is not absolutely clear ◦ e.g., are we talking about a mutable or immutable collection of triples? ◦ maybe we have two different concepts here…

14 (14)  We have a stable “team submission”, widely used by the community ◦ another top priority item…  Additional syntax should be added for graph identification

15 (15)  Is essential for Web Developers  The syntax may not be a complete syntax; to be decided as we go ◦ e.g., no blank nodes, only syntax for Skolemized nodes  The syntax may also include tools for lists, graph identification, etc.  Note that it may make sense to separate that into a different group…

16 (16)  Some features may be deprecated: reification, containers, …  Unclear what “deprecation” means in this context ◦ old RDF graphs should not become invalid…

17 (17)  A number of semantics extensions and features have appeared in Recommendations since ◦ rdf:plainLiteral ◦ “finite” versions of RDF(S) semantics as part of the SPARQL 1.1 entailment regimes ◦ bridge between URI-s as strings and RDF resources in POWDER  Probably useful to reconcile these in one place for wider and easier adoption

18 (18)

19 (19)  oData, for example, is gaining ground: ◦ “…Web protocol for querying and updating data that provides a way to unlock your data and free it from silos that exist in applications today”  Relationship between RDF and these should be defined ◦ oData/Atom based serialization of RDF?

20 (20)  General guidelines for bnode Skolemization ◦ e.g., define a scheme of the form {uuid} ◦ … that could be used by some syntaxes, ie, consumers would know that this is, in fact, an anonymous node  There are a number of Recommendation that rely on Skolemization (e.g., SPARQL)

21 (21)  We currently have plain literal, xsd:string, rdf:plainLiteral… ◦ it leads to, e.g., convoluted SPARQL queries  These should be harmonized

22 (22)  Refresh the vocabulary examples being used  Multi-syntax example (like, e.g., the OWL documents)  Linked Data guidelines should be included ◦ “follow your nose” ◦ usage of owl:sameAs or others ◦ etc.

23 (23)

24 (24)  Issues that arose: ◦ httpRange-14 as a standard ◦ “Cool URI-s for the Semantic Web” ◦ “follow your nose principles” ◦ social contracts around URI-s ◦ etc.  Not clear that these should be Recommendations  Some of the issues might become part of a renewed RDF Primer

25 (25)  Clearly a major problem to be solved  There is a general requirement (graph identification) that is part of the RDF Core  W3C may start a separate group on Provenance vocabularies

26 (26)  Goal: define a subset of (essentially) OWL 2 RL ◦ more palatable to developers ◦ can be “referenced” as an entity, not only a set of rules  Should be done, not clear where and how ◦ not clear this should be part of an RDF Core ◦ would a SWIG Note be enough, or does it need a full Recommendation status?

27 (27)  Mainly on the Linked Data Cloud owl:sameAs is widely used ◦ the usage is not necessarily semantically correct ◦ a vocabulary should be defined to reflect the various usages  could be very close to the relevant SKOS terms, actually…  Some elements may be part of an updated RDF Primer

28 (28)  A bit like RDFa 1.1’s profile mechanism ◦ a single file that collects all namespaces in one  May find its way as part of the JSON serialization ◦ not explicitly out of scope, but has not been added as a requirement either

29 (29)  Mainly the Web Developers’ community needs API-s  But there is already an established set of API-s in Java, Python, etc  The RDFa API work defines its own API which includes a more generic RDF API mainly for Javascript  Not clear whether a separate group would be necessary…

30 (30)

31 (31)  RDF/XML is generally disliked ◦ no one wants to spend time on improving it…  New features (e.g., graph identification) may not find its way to RDF/XML

32 (32)  There is a disconnect between the formal, model-theoretic semantics of RDF(S) and applications ◦ there are also theoretical inadequacies, too  But the overall feedback was: don’t touch it, deployment has learned to live with it, etc.

33 (33)  Bnodes as predicates, literals as subject  Literals as subject has deeply divided the community ◦ some are violently against it, others ask for it ◦ clearly no consensus at the moment!

34 (34)  W3C team should finalize the charter soon  Then the W3C process kicks in ◦ AC members vote with a yea or nay ◦ if the vote is positive: work can begin in early 2010

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