- From: Antoine Isaac <aisaac@few.vu.nl>
- Date: Sun, 28 Aug 2011 16:07:09 +0200
- To: public-xg-lld@w3.org
Hi everyone, It seemed difficult to extract a consensus from the thread :-) Anyway I've tried: http://www.w3.org/2005/Incubator/lld/wiki/index.php?title=Draft_Vocabularies_Datasets_Section2&diff=6006&oldid=5906 As APs are already mentioned in this section (and I understand Tom would add them in other parts of the report) I have removed them from the debatable sentence. And I've tried to make my "gradation" more explicit, while not presenting it as a formal framework. Btw "alignments" do indeed include ontology mappings as expressed in OWL, clearly. Cheers, Antoine > Quoting "Young,Jeff (OR)" <jyoung@oclc.org>: > > >> 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. > > I agree with Jeff here. It seems that AP is being used for any ontology that uses a mix of namespaces or that adopts properties from existing namespaces. This seems to me to be normal practice for ontology development. At what point does a choice of properties become an AP? In DC terms, I think that it becomes an AP only when constraints are added (mandatory, optional, repeatable or not, etc.). > > I commonly hear people use the term AP when someone consciously creates a personalized or modified version of a known metadata schema. So a sub-set of, say, MARC that selects out the fields needed to encode music resources but not cartographic resources would be an AP in this definition. > > Basically, I think we don't have a clear enough definition of AP to use the term in this report without going through a lengthy discussion that would allow us to make it clear. I'd prefer to leave it out, but think that the concept is important and definitely needs more thought. > > kc > >> 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. >> >>> >>> 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. >> >> 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 >> >>> >>> 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 >> >>> >>> Cheers, >>> >>> Antoine >>> >>> > 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 Sunday, 28 August 2011 14:05:47 UTC