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

Dan,

We are talking apples and oranges.

I am talking about the semantics of "class", of which the Observation  
class is an example. [1], for example, says, "A class is the  
descriptor for a set of objects with similar structure, behavior, and  
relationships." (p. 50)

You are talking about aggregations, like an instance of Population is  
an aggregation of Person instances. The Population class still denotes  
a set of instances, each of which is an aggregation of Person  
instances  (e.g., the population of subjects enrolled in trial X).

The idea of a class as denoting a set of individuals is common to UML,  
frame representation, and OWL. I would like to view, in any of these  
formalisms, the Observation class as denoting a set of individual  
observations, and the WhiteBloodCellCountObservation class as denoting  
a subset of the observations whose code is the LOINC code for white  
blood cell count.

Samson

[1] Rumbaugh, Jacobson, & Booch, The Unified Modeling Language  
Reference Manual, 2nd edition.

-- 
Samson Tu                                                     email: swt@stanford.edu
Senior Research Scientist                               web: www.stanford.edu/~swt/
Center for Biomedical Informatics Research 	phone: 1-650-725-3391
Stanford University                                          fax:  
1-650-725-7944





On Jul 23, 2008, at 8:02 PM, Dan Russler wrote:

> Hi Samson,
>
> Sorry for my older-style jargon...
>
> Here is the Wikipedia entry on collection/aggregation. We often  
> called these classes "collectors" in jargon:
>
>