John F. Sowa wrote:
> After the SemTech conference and some further discussions on related
> topics, I realized that many of the debates about the kinds of logics
> and ontologies could be clarified with some useful distinctions.
> Different kinds of applications require different levels of detail
> and precision in the definitions and different levels of expressive
> power in the logic.
> To make the distinctions memorable, good labels are necessary.
> I suggest the following four levels of semantics:
> 0. Zero semantics: Data with no explicit semantics of any kind.
> 1. Lightweight semantics: Some semantic tagging with terminologies
> or folksonomies, loose hierarchies such as WordNet, but no formal
> definitions, logic, or reasoning methods.
> 2. Middleweight semantics: Some formal notations, but only a modest
> amount of logic and reasoning.
> 3. Heavyweight semantics: Detailed ontologies represented in a
> rich version of logic with extensive reasoning.
> There are gradations of levels from Comma Separated Values to Cyc,
> The Linked Data applications are at levels 0 and 1. They usually
> depend on traditional terminologies and folksonomies that have
> no formal definitions.
> Most Semantic Web applications are at levels 1 and 2. (01)
What constitutes a Semantic Web Application? (02)
I would assume you are referring to Application Logic that sits atop and
orchestrates RDF data sources, for instance? (03)
If so, RDF is a form of Linked Data. Thus, Linked Data Spaces also hover
between levels 0 and 2, I would think. (04)
I certainly like your scheme, it will ultimately bring a lot of clarity
to a pretty confusing subject area.
> RDFS and
> RDFa use tags that don't have detailed definitions. Light use
> of OWL supports middleweight semantics, but extensive use of
> all the OWL features begins to cross the boundary between
> middleweight and heavyweight semantics.
I am able to perform backward chained and/or contrained forward chained
reasoning (using SPARQL CONSTRUCTs) against the massive live Linked Data
Space we called the LOD Cloud Cache . Examples include:
owl:sameas, owl:equivalentClass, owl:equivalentProperty, owl:inverseOf,
owl:TransitiveProperty, rdfs:subClass, rdfs:subProperty .. (05)
1. http://lod.openlinksw.com --- live LOD Cloud Cache instance with 17
-- some identifiers with you as co-referent
-- DBpedia data
-- Not so complete data from DBpedia
-- merged data via "owl:sameAs" inference context and resulting union
expansion (for better or worse) . (012)
President & CEO
Twitter/Identi.ca: kidehen (015)
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