Re: [SE] Suggestion of new note

Holger,

A very interesting document indeed - thanks. Here are just some quick comments of the second paragraph of Section 2.

> The vision behind the Semantic Web is to make internet contents machine-readable so that it >can be easier analyzed by software agents and shared between Web Services. For that >purpose, the World Wide Web Consortium (W3C) is recommending a number of Web-based >languages that can be used to formalize internet contents. RDF and OWL can be used to >describe classes, attributes and relationships similar to object-oriented languages. For example, >RDF can be used to define that the class Product has a property hasPrice which takes values of type float. 

This might not be very precise. Domains and ranges in RDF, such as

hasPrice rdfs:range xsd:float,

are global constraints. If we want to assert a local range for the hasPrice property of the Product class, we should use an OWL restriction

Class( Product partial
            restriction( hasPrice allValuesFrom( xsd:float ))).
          
>And you can define a class Purchase with a property hasProducts which relates it 
>with multiple Products. OWL extends RDF by additional constructs to define more 
>complex relations. 

I guess you meant to say complex "classes", as suggested by the following example.

>For example, OWL can be used to define a class DutyFreeOrder as the subclass of all >purchases that have a delivery address to a country that is known to have a free-trade >agreement. The W3C also works on other languages for describing if-then rules and complex >SQL-like queries, but our focus here lies on RDF and OWL. 

Greetings,
Jeff

--
Dr. Jeff Z. Pan  ( http://DL-Web.man.ac.uk/ )
School of Computer Science, The University of Manchester


----- Original Message ----- 
From: "Holger Knublauch" <holgi@stanford.edu>
To: <public-swbp-wg@w3.org>
Sent: Monday, September 19, 2005 12:54 PM
Subject: [SE] Suggestion of new note


> 
> The SETF is currently working on a note intended to act as a Semantic 
> Web Primer for software developers with background in object-oriented 
> languages like UML and Java.  Our goal is to clarify the differences 
> between RDF/OWL and OO languages, and to attract more mainstream 
> developers to add Semantic Web technology to their routine tool kit.
> 
> The current draft of this note is available at
> 
> http://www.knublauch.com/oop/2005/09/19
> 
> We welcome comments of any sort.
> 
> Please note that due to recent problems with the SMI email server, many 
> messages addressed to me have been lost.  I therefore had to switch to a 
> different stanford.edu address.  If you had sent a message to me in the 
> last few days, please consider to resend it again.
> 
> Regards,
> Holger
> 
> 
>

Received on Tuesday, 20 September 2005 07:50:44 UTC