- From: Jim Hendler <hendler@cs.umd.edu>
- Date: Sat, 11 May 2002 20:49:06 -0400
- To: webont <www-webont-wg@w3.org>
The following is a long message - but please bear with me - I think it important to a critical area of our WG. As you might guess I've been thinking hard about the issue of levels of compliance, goals for the WG, etc. given the recent issues we've had with reaching consensus about these issues. I've come to the conclusion that there are essentially two main approaches to ontologies at the moment, and our group reflects members of both. I think it is important to understand these different (not competing!) goals, and think about how we make sure our langauge is useful in both cases. I am going to use a real world example, but please note that it is only meant to illustrate the issue, and not to imply either that that is the only place the issue comes up, or that the particular application is in any way more interesting than the others. The set up: A large govt organization in the US uses a set of Description Logic tools on a daily basis to develop a monthly vocabulary that they release to the world. The development process uses about seven full-time employees and some very complex (proprietary code). The current vocabulary release is in XML, against a DTD also available. Why would they want OWL?? --------- 1) Publishing the vocabulary: the THESAURUS level What we've been calling OWL core or Level 1 is what I'm going to call the thesaurus level -- this is also our "RDFS on steroids" My research group at Maryland wrote a Perl program to turn their monthly vocabulary dump into DAML+OIL. We used only the RDFS primitives, cardinality (they needed some restrictions to specific cardinalities - not just 1/0) and they needed unique property. So for publishing the thesaurus, they need a simply language that extends RDFS and looks like we've been calling OWL core -- they could put this into use tomorrow (and want to) 2) Building the vocabulary: the INFERENCE level But what about what we've been calling level 2? Do they need that? The answer is yes. They wouild like to find a way to share the ontology development with another organization or another group in their organizing a different tool kit - they are all using different tools. So they would like a way to share their class definitions and etc. between tools. For this they need a more extensive langauge. This is something they could not do right away, because their tool vendors would need to be involved - but if it was doable, they would indeed put pressure on their vendors to make this available and to make the tools interoperable. ------------ As a result, we see their are really two very different uses they (and many others) would like to put our language too. One is to writing down the "output" of the ontology creation process (the thesaurus level) the other is to write down the inputs/specs of that creations (the inference level). Many of the people I talked to at the WWW believe there is an immediate need for the thesaurus level, but when I discuss the inference level they see use there as well. Some (for example the genomics folsk Ian works with) are already doing the inference level and others are seeing them talk about it and getting excited. So my conclusion is that if our WG is going to fill "our client's needs" we must do both, we must discuss them clearly, and we must make it clear that the inference level builds on top of the thesaurus level (much as our thesaurus level extends RDFS in a functionality sense). I think the jury is still out on what the best way to describe this is (levels, document chapters, naming of functionality)- but I think it would be very valuable for us to start more clearly examining the real world issues like this with respect to how we'll make the language available - and how guide will write it up. As I'll say in another message later -- WWW has been amazingly exciting - a lot of real people want us to produce and will start using it immediately -- we will literally have millions of new OWL statements and thousands of pages using it soon after release -- so let's do it!! -JH -- Professor James Hendler hendler@cs.umd.edu Director, Semantic Web and Agent Technologies 301-405-2696 Maryland Information and Network Dynamics Lab. 301-405-6707 (Fax) AV Williams Building, Univ of Maryland College Park, MD 20742 http://www.cs.umd.edu/users/hendler
Received on Saturday, 11 May 2002 20:49:19 UTC