Re: An argument for bridging information models and ontologies at the syntactic level

Peter and Vipul...See below...dan

Kashyap, Vipul wrote:

>  
>
>     IMHO, codes don't represent classes in some information model. An
>     information model has classes like Observation, whose instances
>     are clinical statements made by some entity (person or machine). I
>     think information model is "meta" in the sense that its instances
>     are statements  
>     [VK] This the reason I think theHL7 is a meta-model rather than an
>     Information Model. Of course this depends on the viewpoint you
>     take and the information architecture you adopt.
>
<dan> With apologies to Peter in case I misrepresented your SOA 
presentation...Last week, Peter Elkin of Mayo Clinic delivered a 
presentation where he called the HL7 RIM a "first order ontology" 
because of the abstraction level of the RIM. He called the models 
derived from the RIM, e.g. analytic models, patient care document models 
like CDA, etc, "second order ontology" because they add a layer of 
concreteness to the abstractions of the RIM, i.e. an object with 
classCode of observation and moodCode of order becomes an "observation 
order object" with neither a classCode nor a moodCode. Finally, the 
coding systems themselves support the concreteness of a "third order 
ontology." For example, the SNOMED concept becomes an object itself 
without a code attribute, moodCode attribute, or classCode attribute, 
e.g. a WBC order. />

>      
>      (The observation that "John has diabetes") about something that
>     happens in the real world (the person named John has an instance
>     of Diabetes).  In BFO term, the observation is an instance of
>     information-content-entity, as opposed to an assertion about the
>     John instance of Person and an instance of Diabetes.
>     [VK] While not disagreeing with the above, here is one way to
>     model it in terms of multi-layer representation
>      
>     Oberrvation = MetaClass
>     Instances of Observation MetaClass = DiabetesObservation Class =
>     The set of statements that A Person has Diabetes
>     Instances of DiabetesObservation Class = The statement "John has
>     Diabetes"
>      
>     The fundamental issue here is that in the HL7/RIM contains a filed
>     called Observation.code which will be assigned the code for the
>     class Diabetes in Snomed, etc.
>
<dan> see above for the "first order to third order model." Your 
metaclass looks like Peter's "first order ontology." However, your 
"instances" get introduced too early...your "instances" point to actual 
medical record assertions, and Peter's model suggests that there is more 
"in between." In Peter's model, the actual medical record assertion 
would be an instance of his "third order ontology." />

>
>      I don't understand how a class of HbA1c can be an instance of the
>     RIM Observation class.  I don't see how the Observation class
>     having the value field is the issue.
>      
>     Observation.code = Code for HbA1c
>     Observation,value = Value for HbA1c
>      
>     One way of looking at the HL7/RIM as a meta-model is aa follows:
>     Observation = MetaClass
>     Instances of Observation MetaClass = HbA1cObservation Class = The
>     set of HbA1c observation for a given person
>     Instances of the HbA1c Class = The Value for HbA1c for John at a
>     given point in time.
>      
>     So one could view the HL7/RIM as an EAV model (Entity =
>     Observation.code = HbA1c, Attribute = Observation.value, Value =
>     Actual value)
>     which "serializes" or represents this multi-layer represntation.
>
<dan> I completely agree that the HL7 RIM is one level more "concrete" 
than the earlier EAV models. The EAV model represents the ultimate in 
abstraction, similar to RDF triples. Perhaps Peter would be more correct 
to say that EAV is a "first order ontology" and that the HL7 RIM is a 
"second order ontology." />

>      
>     Hope that clarifies this modeling approach.
>      
>     Cheers,
>      
>     ---Vipul
>      
>
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