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Subject: Review and Comments on initial draft Semantic Representations of the UN/CEFACT CCTS-based Electronic Business Document
Review and
Comments
Semantic
Representations of the UN/CEFACT CCTS-based Electronic Business Document
Review
GS1, UBL, and OAGIS documents will all eventually be semantically
harmonized with the CCTS information model and with the CC Library. Harmonization
means that document structure will be mapped into CCTS information model
patterns and that semantic primitives for messages will be found in the CC
Library. SET has proposed an ¡°upper ontology¡± of OWL DL assertions, with content
taken from the CCTS model of business information. The upper ontology is
combined with additional assertions describing information structures from
messages that are defined by the message standards bodies (GS1, UBL, and
OAGIS). The ontologies are combined and ¡°classified¡± to produce a completed set
of asserted and inferred OWL claims, containing many class equivalences. These
equivalences form the basis for maps between information elements within the
overall documents. The resulting maps are not normally complete, and ¡°heuristic¡±
rules are used to derive additional class equivalences until all
¡°corresponding¡± parts of documents are connected. (For a given pair of
documents, it may still be that some parts in either document have no parts in
the other; each document may, for example, make use of some semantic primitives
not found in the other. Comments &
Questions.
Given that GS1, UBL and OAGIS are seeking to harmonize against the CC
Library, there should be a number of correlations based not on the CCTS models,
but on the low level maps of document parts to core components. David Webber
leveraged these ¡°couplets¡± to discover equivalences through the UID dictionary
cross-references which he then adds to his transforms or More generally, the framework provided in the current draft seems to
combine a very constrained DL approach to knowledge representation and
inference, with several escape mechanisms to maneuver around various obstacles
tied to both the ontology¡¯s limited content (insufficient to derive various
needed equivalences) and the inference engines constraints on inferences. The need for Jess based augmentation of inferences[i]
and special rules that have sufficient content to derive additional
equivalences seems to be ¡°a patch¡± for something that points to an inadequacy
in the CCTS model, the CC Libraries (which may not be adequately leveraged), or
perhaps in the constraints on inference rules. Maybe what we are seeing is that
there is a need for a richer ontology in CCTS? Or more information in the CC library? If we are to add more general rules and inferences to overcome OWL
limitations, I think SWRL could be considered as at least connected to the OWL
technology in some ways. In addition, the Pellet reasoner is said to support
SWRL reasoning, so that demonstrations could still be run within Prot¨¦g¨¦, if
that is the preferred development environment. SWLR can be stored in an OWL
file, apparently, and then the additional equivalences would come out of OWL
syntax and DL reasoners with greater inferential powers. However, the fact that these additional rules have not come from an analysis
of the content of the CCTS models, the specifics about GS1 or UBL or OAGIS
information structures, or the CC library suggests that the project falls short
as a proof of concept for UN/CEFACT technologies in producing maps. At the very least, the precise details need to be captured with more
care about just what can be derived (without the heuristic patches) and what
those equivalences or inclusions can accomplish with respect to generating maps
between documents. [i]
¡°Note
that a DL reasoner by itself cannot process predicate logic rules and we resort
to a well accepted practice of using a rule
engine to execute the more generic rules and carry the results back to the DL reasoner through
wrappers developed. ¡° |
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