- From: ZENG, MARCIA <mzeng@kent.edu>
- Date: Thu, 25 Aug 2011 15:48:00 -0400
- To: "Young,Jeff (OR)" <jyoung@oclc.org>, Antoine Isaac <aisaac@few.vu.nl>, "public-xg-lld@w3.org" <public-xg-lld@w3.org>
Hi, all, Sorry for being away for a while. Just read your emails. On 8/25/11 1:37 PM, "Young,Jeff (OR)" <jyoung@oclc.org> wrote: >> As far as the "linking issue" appendix is concerned, as discussed >> during the call, I implemented the following modifications: >> >http://www.w3.org/2005/Incubator/lld/wiki/index.php?title=Draft_Vocabul >> aries_Datasets_Section2&diff=5906&oldid=5882 > >I like this. I'm a little uncomfortable with the overlap between >"semantic alignment" and what the OWL guide calls "ontology mapping": > >http://www.w3.org/TR/2004/REC-owl-guide-20040210/#OntologyMapping > >I'm sure there is enough of a difference, though, that we shouldn't fret >about it. Thanks for the revision Antoine did right after the telecon. In the definition the word 'links' is where I stopped for a minute. "+"Alignments" are links between semantically equivalent, similar, or related entities across different value vocabularies, metadata element sets, or datasets." Here we mean conceptually the 'links', right? Is it more a connection? Is 'alignment' a process or product? If it is a process, then it leads to the links/connections. > >> The point was to hint here at some "interoperability gradient". >> Ideally, there would be APs directly re-mixing existing classes and >> properties. > >I'm uncomfortable using the term AP even for situations where a variety >of existing classes and properties are getting reused. An OWL ontology >can be created to document this situation, even if no new terms are >being defined there. Granted, you don't see much of that happening yet, >but presumably that's presumably because people are still trying to wrap >their minds around OWL in general. > >> But there are many situations in which re-using a >> vocabulary comes with risks/costs that could motivate coining one's >own >> "duplicate" elements. Consider what schema.org did: they just prefered >> to coin all the elements they need, rather than spend time shopping >> around for existing elements--which may be not well maintained anyway. >> That's maybe not the best practice around, but that will continue to >> happen. In such cases, establishing alignments between element sets is >> a lesser evil. > >As a species, I think we are still beginners in terms of modular >thinking. I can't think of a single existing model or set of models that >doesn't make me squirm and shake. "Alignments" or "mappings" give me >hope that we will be able to adapt regardless. Both of you have expressed observations that there is no 'one-size-fits-all' and there are variety of ways when dealing with alignments, mapping, reuse, or creation of metadata element sets. We could acknowledge the diversity of approaches. > >> >> The "gradient" of best practice here would be: (1) own duplicate >> element sets with no alignment; (2) own element sets with alignment to >> existing vocabularies (3) "true" APs with re-use of existing >> vocabularies. These seemed to be a fair grouping. They may align well with the 5 star criteria TBL suggested. I think when you said alignment to or reuse existing vocabularies, should we indicate those existing vocabularies should be well-recognized standards? > >I agree with these idealized gradients with a couple of caveats. > >1) Existing vocabularies that don't conform to best practice recipes >suck: http://www.w3.org/TR/swbp-vocab-pub/ >2) Some existing vocabularies (even popular ones) can be very weird and >arguably would be better off being mapped >3) The ability to transform domain-specific vocabularies into foreign >vocabularies shouldn't be that far off if the mappings exist These are true. > >> >> I'm not saying that it was clearly worded here, far from it :-) >> I can also live with this point being mentioned in another section. >But >> I wanted to warn against making this disappear, altogether. > >I suspect that all these thoughts are too controversial to used on short >notice, though. > >Jeff Right. If we have more time and more experience we can provide better information. But showing the diversity and possible new approaches in this matter is also a good reference. > >> >> Cheers, >> >> Antoine Thanks, Antoine. Can we finalize this today? I will be on the road tomorrow (forwarding the hurricane actually). So I hope we fix this and keep this appendix nicely. Marcia >> >> > Dear all, >> > >> > Re-reading the paragraph in [1]: >> > >> > A similar concern can be voiced regarding metadata element >sets. >> As >> > testified in the Linked Open Vocabularies inventory, >> practitioners >> > generally follow the good practice of re-using existing element >> sets or >> > building "application profiles" of them. And some projects, >such >> as the >> > Vocabulary Mapping Framework, aim at supporting that process. >> But the lack >> > of long-term support for them threatens their enduring meaning >> and common >> > understanding. Further, some reference frameworks, notably >FRBR, >> have been >> > implemented in different RDF vocabularies, which are not always >> connected >> > together. Such situation lowers the semantic interoperability >of >> the >> > datasets expressed using these RDF vocabularies. The community >> should >> > encourage the coordinated re-use of element sets for particular >> entity >> > descriptions, their extension through, e.g., application >> profiles, or their >> > alignment using, e.g., semantic relations from RDFS and OWL. >> Here, we hope >> > that better communication between the creators and maintainers >> of these >> > resources, as encouraged by our own incubator group or the LOD- >> LAM >> > initiative, will help to consolidate the conceptual connections >> between >> > them. >> > >> > ...where "a similar concern" refers to "semantic links across value >> vocabularies". >> > >> > Looking closer: >> > >> >> A similar concern can be voiced regarding metadata element sets. As >> >> testified in the Linked Open Vocabularies inventory, practitioners >> >> generally follow the good practice of re-using existing element >sets >> or >> >> building "application profiles" of them. >> > >> > If we mean Dublin-Core-style application profiles (as Singapore >> Framework is >> > cited further on in the paragraph), then we could say something >like: >> > >> > A similar concern can be voiced regarding metadata element >> sets. As >> > testified in the Linked Open Vocabularies inventory, >> practitioners >> > generally follow the good practice of re-using existing >element >> sets or >> > building "application profiles" that re-use elements from >> multiple sets. >> > >> > Then, I do not really understand the first part of this sentence: >> > >> >> The community should encourage the coordinated re-use of element >> sets for >> >> particular entity descriptions, their extension through, e.g., >> application >> >> profiles, or their alignment using, e.g., semantic relations from >> RDFS and >> >> OWL. >> > >> > The phrase "encourage the coordinated re-use of element sets for >> > particular entity descriptions" seems to be saying something like: >> > >> > ...promote the use of common patterns of mixing vocabularies >for >> > describing particular types of things. >> > >> > However, I do not think this reference to application profiles >really >> belongs >> > in a section on alignment. >> > >> > Rather, I would like to propose the following: >> > >> > -- That the section "The linking issue" (vague, because the whole >LLD >> XG report is >> > arguably about a "linking issue") be renamed something like: >> > >> > Semantic alignment >> > >> > -- In this case, the first sentence -- "Many semantic links across >> value >> > vocabularies are already available..." -- could be preceded with >> a definition >> > along the lines of: >> > >> > "Alignments" are links between semantically equivalent, >> similar, or >> > related terms or entities across different value >> vocabularies, metadata >> > element sets, or datasets. >> > >> > -- The notion of application profiles is more appropriately >> referenced in the point >> > about re-using patterns: >> > >> > In the paragraph: >> > >> > Design patterns allow implementers to build on the experience >of >> > predecessors. Traditional cataloging practices are documented >> with a rich >> > array of patterns and examples, and best practices are starting >> to be >> > documented for the Linked Data space as a whole (e.g., >> > <ref>http://linkeddatabook.com/editions/1.0/#htoc61</ref>). [*] >> What is needed >> > are design patterns specifically tailored to LLD requirements. >> Such design >> > patterns would meet the needs of people and developers who >> understand new >> > techniques through patterns and examples and will increase the >> coherence of >> > Library Linked Data overall. >> > >> > I propose inserting a sentence: >> > >> > Application profiles >(http://dublincore.org/documents/singapore- >> framework/) >> > provide a method for a community of practice to document and >> share patterns >> > used for describing specific types of materials. >> > >> > -- ...and application profiles are also relevant to "data design" >> [2]: >> > >> > Another boost for Linked Data is the growing use of OWL for >> purposes of >> > data design. Prior to OWL, domain experts could use RDFS to >> create metadata >> > element sets, but there was no way to map equivalencies across >> > vocabularies. Among other features, OWL includes an upgrade to >> RDFS to >> > support ontology mapping. This allows experts to describe their >> domain >> > using community idioms, while still being interoperable with >> related or >> > more common idioms. A variety of tools related to OWL can be >> found on the >> > W3C's RDF wiki and OWL wiki. Unified Modeling Language (UML) >> tools are also >> > value to help designers represent and manipulate domain models >> visually. >> > The Ontology Definition Metamodel (ODM) specification should >> help bridge >> > some of the gaps between UML and OWL. [*] >> > >> > I propose to add: >> > >> > Application profiles >(http://dublincore.org/documents/singapore- >> framework/) >> > provide a way to specify how a community of practice defines a >> > domain model and re-uses specific vocabularies in order to >> create metadata >> > conforming to a particular pattern. >> > >> > Tom >> > >> > [1] >> >http://www.w3.org/2005/Incubator/lld/wiki/DraftReportWithTransclusion#T >> he_linking_issue >> > [2] >> >http://www.w3.org/2005/Incubator/lld/wiki/DraftReportWithTransclusion#T >> ools_for_data_designers >> > [3] >> >http://www.w3.org/2005/Incubator/lld/wiki/DraftReportWithTransclusion#D >> evelop_and_disseminate_best-practices_design_patterns_tailored_to_LLD >> > >> > >> >> > > >
Received on Thursday, 25 August 2011 19:48:44 UTC