RE: Multi-layered Knowledge Representations for Healthcare (was RE: An argument for bridging information models and ontologies at the syntactic level)

Dan,
 
Looks like there is increasing convergence in our view points and some minor
divergences.

	<dan> I'm confused...can you illustrate in UML, perhaps with the blood
pressure example? />
	[VK] The UML Diagram illustrating WBC is attached with this e-mail (GIF
format). Look forward to your thoughts on this issue.
	 
	
	<dan> depends what one means when one says they "create" an ontology. An
ontology is just another name for a belief system. When one writes down one's
beliefs, one is not really creating an ontology. />
	[VK] Well, that could be part of the confusion. Another viewpoint is
that an ontology is a knowledge artifact that has a broad consensus on what it
means. 
	
	 <dan> looks like the antecedent to my statement "In small domains..."
is lost somewhere above. In any case, in small domains, one can easily get a
picture of all the classes on a small diagram that is easy for people to look at
together. In large domains, the multitude of classes makes the diagram huge and
makes it difficult to express the essentials on one computer screen or piece of
paper (too many trees to see the forest). The HL7 UML model of the RIM that
makes mood and class code attributes is simply a pictorial approach that assists
discussion in many venues, i.e. one doesn't need a huge piece of paper on the
wall! Again, not to get hung up in pictures of concepts. Focus on the concepts.
/>
	[VK] Yes, the requirement to make a model compact shouldn't negatively
impact the understandability of the model. Mood and type codes can be very
tricky to understand. Also these are some sort of attributes at layer 1 as
opposed to Layer 2. In some cases, the model may be more understandable in one
explicitly represents subclasses based on these codes. 
	

					[VK] OK, then what you are suggesting is
that a template is logically equivalent to a set of constraints on the
information model. Would be interested in representing these conformance
statements as a set of OWL axioms 

	<dan> I agree...Adding an OWL version of these conformance statements
would be a great next step. />
	 
	I hope this long-winded description helps in this "multi-layered
Knowledge Representation" discussion. How one classifies the concept of
"context" for a given concept, or the concept of "conformance testing the
constraints on an aggregation of structure and vocabulary" in a multi-layer
Knowledge Representation is not clear to me. 

			<dan> There are many kinds of "conformance." One basic
example is testing the contents of a data entry field before committing the
contents to the database to make sure the contents have the right kinds of
characters, e.g. numeric, alphabetic, etc. 
			[VK]  This is basically syntax checking which checks for
the format in which data is represented and is not an information modeling or
semantics issue.
			 
			 Schematron testing in CDA tests the conformance of the
XML structure and the codes and other values within the XML structure (think
terminology) to make sure the wrong codes aren't used in a specific XML
structure. 
			[VK] XMl structure testing can be tricky because the
healthcare IT community has used XML Schema to represent information models. XML
Schema is a language designed to describe the format and structure of XML
documents in contrast with languages
			such as RDF, OWL and UML which seek to describe the
semantics underlying these documents. So "checking for conformance of XML
Structure" could either (A) check for the validitiy of the structure of the XML
Document or for (B) validity of the information
			model (R-MIM) underlying the XML document. What would be
relevant is (B) and we could try to use OWL axioms to describe the type of
conformance statements represented by (B)
			Finally matching terminologies is a semantics issues and
OWL/Description Logics have been used to represent Snomed and terminology
matchin can be expressed in terms of OWL subsumptions.

	<dan> Again...agreed...OWL is a natural tool for this task />
	

			 
			 I'm sure that a broader definition of conformance can
be created that includes things as basic as character validation and as complex
as information model/vocabulary model validation. />
			[VK] What can easily be implemted using OWL is
information model/vocabulary validation
			 
			In Summary, we could propose the following Task Force
which looks at the following aspects as a part of HCLSIG:
			(A)  Determine the feasibility of OWL as a common
representational formalism for healthcare delivery information models and
terminologies
			(B) Define and implement the notion of "Semantic
Conformance" of an information model to HL7/RIM + Terminologies (may require a
restructuring of the RIM to some extent)
			 
			Let me know what your thoughts are on this and we can
figure out the next steps.
			 
			Cheers,
			 
			---Vipul


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Received on Monday, 21 July 2008 21:02:39 UTC