W3C home > Mailing lists > Public > public-swbp-wg@w3.org > November 2006

Re: Time Ontology in OWL WD published

From: Bernard Vatant <bernard.vatant@mondeca.com>
Date: Fri, 10 Nov 2006 16:46:03 +0100
Message-ID: <45549EBB.2050604@mondeca.com>
To: public-swbp-wg@w3.org

Hello all

Some remarks on the Time Ontology WD I just start to explore.
I'm much interested by the rich modeling of time:Interval, and 
singularly the time:ProperInterval, but am puzzled by all those 
properties having it for both domain and range, without further 
comments. Unless I miss something, there is no explanation about their 
specific semantics and intended use, neither inside the RDF file, nor in 
the presentation document. One can only guess from the URI what is the 
semantics of intervalMeets vs intervalOverlaps or intervalEquals (the 
latter I really don't have any guess on what it is intended to convey, 
certainly equality, but which kind of equality?). And actually, I should 
not even try to guess, since there should not be any semantics embedded 
in those URI fragments, right? Are semantics defined in extra 
documentation. If so, pointers, please!
How are people supposed to use those properties correctly? I suggest at 
least some prose should be added either somewhere in the Draft, and/or 
preferably as comments in the RDF file itself.
Moreover, maybe I'm wrong, but seems to me those different properties 
are formally linked to each other by rules, like e.g., the following in 
SPARQL (if I got intervalOverlaps semantics and SPARQL syntax correctly 
...) BTW I find strange that time:inside has domain time:Interval and 
range time:Instant. One would expect it the other way round ...

PREFIX time:    <http://www.w3.org/2006/time#>

CONSTRUCT   { 	?x time:intervalOverlaps ?y }

WHERE       { 	?y time:hasBeginning ?a.
		?y time:hasEnd ?b.
		?x time:inside ?a.
		?x time:inside ?b.
	    } 		

Cheers

Bernard

-- 

*Bernard Vatant
*Knowledge Engineering
----------------------------------------------------
*Mondeca**
*3, citÚ Nollez 75018 Paris France
Web:    www.mondeca.com <http://www.mondeca.com>
----------------------------------------------------
Tel:       +33 (0) 871 488 459
Mail:     bernard.vatant@mondeca.com <mailto:bernard.vatant@mondeca.com>
Blog:    Lešons de Choses <http://mondeca.wordpress.com/>
Received on Friday, 10 November 2006 15:46:15 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Tuesday, 8 January 2008 14:17:22 GMT