- From: Jeff Heflin <heflin@cs.umd.edu>
- Date: Thu, 19 Oct 2000 15:30:52 -0400
- To: "Hart, Lewis" <lhart@grci.com>
- CC: www-rdf-logic@w3.org
"Hart, Lewis" wrote: > > > To me the definition of 'globally agreed to' means a specified version > of the ontology, as given by its URL, which everyone who cares knows > about. The kid in the Philippines could publish whatever he wants, but > it doesn't mean anyone will use it. If an author intends to use the > agreed to meanings, then they must reference the appropriate defining > ontology: > > <rdf:RDF > xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" > xmlns:daml="http://www.w3.org/2000/08/daml-ont#" > > xmlns:EC="http://www.e.commerce.org/standards/ontology#" > > > > <EC:Purchase_Order> > ... blah blah blah > </EC:Purchase_Order> > </rdf:RDF> > > If a different ontology (say xmlns:EC="http://hackers.net/ontology") is > referenced, > then you do not necessarily know what is meant. You may or may not trust it. > The problem comes not so much in interacting with a site or exchanging messages between agents (in which case certificates and/or case-by-case acceptance might work sufficiently), the problem comes with an "ontology-based" search engine. Here's an overly-simplified example: Let's say we have the following in our E-commerce ontology: Product isa Thing Computer isa Product ... Let's say someone has built the first quantum computer and is offering it for sale. They need to extend the E-commerce ontology with a special QuantumComputerOntology, which might include the following: QuantumComputer isa Computer Finally, on a web page this person now says: Q2000 instance-of QuantumComputer Let's say I'm in the market for a new computer. I might be interested in the QuantumComputer if I knew about it, but if I didn't know about the QuantumComputerOntology beforehand, I couldn't say that I trust this ontology. Thus, my query about Computers will never return this instance b/c I don't believe that "QuantumComputer isa Computer." In this case, it would be nice if my reasoner automatically used the new ontology, so that my query would return the Q2000 as well as more traditional computers. However, let's say that some hacker creates an ontology the extends the E-commerce ontology with this beauty: Thing isa Computer Now if my reasoner automatically accepts this ontology, I'm in for a world of trouble. It will tell me that everything is a computer! The problem is we want different behaviors depending on our a priori knowledge of the ontology. How do we make sure the right thing is done? I don't want users of the brave new web to be asked every minute by their computers if they accept John Doe's new ontology (which may be very complicated and contain implications that they don't understand), but I also don't want some guy selling widgets out his basement to have to wait 3 months for some certification body to say his ontology is trustworthy before people can even find out that he sells that kind of widgets! That goes totally against the distributed nature of the Web! Jeff
Received on Thursday, 19 October 2000 15:30:59 UTC