Re: How to model valid time of resource properties?

Hi all

Quickly browsing this thread, seems to me that the Property Reification
Vocabulary [1] provides exactly what is needed without going through the
burden of explicit reification or named graphs, and I did not see it
mentioned unless I missed something.
It would be cool if this vocabulary could move upwards to some standard
status (it's work in progress, last version is Feb 2011). Certainly at
least one of the great brains beyond it is lurking here :)

http://purl.org/ontology/prv/core#


2014-10-16 0:02 GMT+02:00 John Walker <john.walker@semaku.com>:

>   Hi
>
>
> On October 15, 2014 at 2:59 PM Kingsley Idehen <kidehen@openlinksw.com>
> wrote:
>
>  On 10/15/14 8:36 AM, Frans Knibbe | Geodan wrote:
>
>  On 2014-10-13 14:14, John Walker wrote:
>
>
>  Hi Frans,
>
>  See this example:
>  http://patterns.dataincubator.org/book/qualified-relation.html
>
>
> Thank you John! Strangely enough, I had not come across the Linked Data
> Patterns book before. But I can see it is a valuable resource with
> solutions for many common problems. And it looks pretty too! I am sure it
> will come in handy for problems that I haven't stumbled upon yet.
>
> A nice thing about this solution is that it doesn't need any extensions of
> core technologies. I do see some downsides, though:
>
> Let's assume I want to publish data about people, as in the examples. A
> person can have common properties defined by the FOAF vocabulary, like
> foaf:age or foaf:based_near. Properties like these are likely to change. If
> I want to record the time in which a statement is valid I would have to
> create a class for that relationship and add properties to that class that
> will allow me to associate a start time and an end time with the class. But
> by doing that I would not only be forced to create my own vocabulary, I
> would also replace common web wide semantics with my own semantics. Or
> would it still be possible to relate the original property with the custom
> class somehow?
>
>  Personally I would not use this approach for foaf:age and
> foaf:based_near as these capture a certain snapshot/state of (the
> information about) a resource. Having some representation where the
> foaf:age triple could be entailed could lead to having multiple conflicting
> statements with no easy way to find the truth.
>
> Having a clear understanding of the questions you want to ask of your
> knowledge base should help steer modelling choices.
>
>  In the cases known to me that require the recording of history of
> resources, *all* resource properties (except for the identifier) are
> things that can change in time. If this pattern would be applied, it would
> have to be applied to all properties, leading to vocabularies exploding and
> becoming unwieldy, as described in the Discussion paragraph.
>
> I think that the desire to annotate statements with things like valid time
> is very common. Wouldn't it be funny if the best solution to a such a
> common and relatively straightforward requirement is to create large custom
> vocabularies?
>
>  If you want to be able to capture historical states of a resource, using
> named graphs to provide that context would be my first thought.
>
> If that resource consists of just one triple, then RDF reification of that
> statement would also work as Kingsley mentions.
>
>
> Regards,
> Frans
>
>
> Frans,
>
> How about reified RDF statements?
>
> I think discounting RDF reification vocabulary is yet another act of
> premature optimization, in regards to the Semantic Web meme :)
>
> Some examples:
>
> [1] http://bit.ly/utterances-since-sept-11-2014 -- List of statements
> made from a point in time.
> [2] http://linkeddata.uriburner.com/c/8EPG33 -- About Connotation
>
> --
> Regards,
>
> Kingsley Idehen
> Founder & CEO
> OpenLink Software
> Company Web: http://www.openlinksw.com
> Personal Weblog 1: http://kidehen.blogspot.com
> Personal Weblog 2: http://www.openlinksw.com/blog/~kidehen
> Twitter Profile: https://twitter.com/kidehen
> Google+ Profile: https://plus.google.com/+KingsleyIdehen/about
> LinkedIn Profile: http://www.linkedin.com/in/kidehen
> Personal WebID: http://kingsley.idehen.net/dataspace/person/kidehen#this
>
>
>
>



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