Recently I had an interesting conversation with Werner Cuesters, professor in Bufallo and colleague of Barry Smith. He has some theory about ontology maintenance and versioning and it considers both "classes" and "instances". Both can change either because you made en error, either you view on the world changed, either because the world changed . It turns out that you can only handle changes if you know for each change exactly what de reason of the change was. That reason should be documented in the system. I refer to a powerpoint which is available from his site (slides 39-42). Maybe it makes sence to dig a little deeper in his publications or contact him. The presentation is (amongst other topics) about the quality of an ontology (be it on class level or instance level) , the fact that at a certain point in time some concepts are rightfully or wrongly present or absent and the corrective measures you should take.
______________________________________ Dr. Dirk Colaert MD Advanced Clinical Application Research Manager Agfa Healthcare mobile: +32 497 470 871 "Xiaoshu Wang" <[EMAIL PROTECTED]> Sent by: [EMAIL PROTECTED] 11/01/2007 23:30 To "'w3c semweb hcls'" <public-semweb-lifesci@w3.org> cc "'w3c semweb hcls'" <public-semweb-lifesci@w3.org> Subject RE: Versioning vs Temporal modeling of Patient State Chimezie, > If a class has a particular 'definition' (i.e., the criteria > for membership of its instances) at a particular time and > that definition 'changes' then we are talking about a > different class altogether not a 'version' of the same class Yes. That is why I consider the OBO Foundry's wording "the original URI should still point to the old term or concept, even if it is deprecated" (From William Bug) is a bit self-contradicted. In software engineering, if a class or a function is labeled as "deprecated", it intends to warn the programmers that the code/functionality might not be available some point in the future. But when crafting an ontology, we present our view on certain reality. If the view is wrong or inadequate, there will certainly less cited (i.e., linked) by others and eventually die. Hence, the notion of deprecation seems not apply if the URI is to be persisted. (I strongly support this OBO policy). But on the other hand, there is situiations that the crafted ontology is due to errors but not due to different theories or views. Hence, we need to "deprecate" certain URIs. I think it is necessary to make distinctions between the two and give different URI policies. Xiaoshu
