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

Hi Vipul,

Peter is right that the term "EAV" is a data schema implementation 
model, even though it maps directly to a classic proposition model with 
subject, predicate, and object of the predicate.

Layer 0 then would be the most abstract layer consisting purely of 
formal propositions. In this layer, some propositions may express 
relationships between one or two other propositions, but otherwise, no 
grouping of propositions (classes) nor inheritance are characteristic of 
this layer.

Peter brings up a good point about the need to deal with belief and 
values in the model. After all, an ontology is really a belief system 
asserted by one or more people. How does one bring belief into a model, 
e.g. realism, creationism, etc?

Regarding your note below on Layer 2...The question is whether there are 
finer layers of distinction between level 1 and layer 2 (before one 
actually creates instances that apply to individual patients)?

Dan

Kashyap, Vipul wrote:

> Dan and Peter,
>  
> Based on conversations on this topic, there appears to be consensus of 
> the need for multi-layered knowledge representation schemes
> for heatlhcare.  Will be great if we could brainstorm and come to some 
> sort of consensus on these "layers". Would like to propose a
> strawman as enumerated below.
>  
> Layer 0 = Entity - Attribute - Value or RDF triple based rerpesentations.
> Layer 1 = MetaClasses, e.g., Observation as in HL7/RIM
> Layer 2 = Classes in a Patient Model, Document Models, etc, e.g., the 
> class of HbA1c results for a class of Patients.
> Layer 3 = Data that are instances of Classes, e.g., a particular HbA1c 
> result for a patient John...
>  
> As per your e-mail, you seem to be suggesting that there is something 
> in between Layer 1 and Layer 2. However, please note that Layer 2 consists
> of classes of assertions in the patient record and not instances.
>  
> More reespnses are embedded in the e-mail below.
>  
> <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. 
>  
> [VK] Are there mathematical ways of describing these "derivations" for 
> e.g., by using operations such as instantiations and 
> generalizations/specializations.
>  
> Also, in the above, it's not clear what the semantics of an 
> "observation order" object is?
> For e.g., observations and orders are semantically distinct concepts, 
> so in some sense an observation order class is likely to be unsatisfiable?
>  
> The semantics of "moodCode" is not clear in Knowledge Representation 
> terms. For instance, do various mood codes partition the instances of 
> a class
> into subclasses that are possbily mutually disjoint?
>  
>  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. />
> [VK] One way of looking at a Snomed code is that it defines a 
> class (e.g., blood pressure) of all the instances of blood pressure 
> readings which would imply that it belongs to Layer 2 as defined above? 
>
>>         <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." />
>>         [VK] Agree. As per the layering introduced above,  Layer 2
>>         would correspond to classes of assetions and Layer 3 would
>>         correspond to actual instances or assertions.
>>
>>          <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." />
>>          
>>         [VK]  Agree: As per layering introduced abiove,  The EAV/RDF
>>         triples layer could be layer 0, and the HL7/RIM layer could
>>         be layer 1
>>
>>          
>>         Look forward to further brainstorming and feedback on this.
>>          
>>         Cheers,
>>          
>>         ---Vipul
>>
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