Re: foaf:page vs. foaf:topic

On Sat, Feb 13, 2010 at 7:02 AM, Martin Hepp (UniBW) <
martin.hepp@ebusiness-unibw.org> wrote:

> Dear all:
>
> In the context of the GoodRelations ontology, there is a regular need to
> link
>
> 1. a data entity (e.g. representing a company, a product, or an offer)
>
> with
>
> 2. the URI of a XHTML/HTML Web Resource that contains human-readable
> information about that entity (often combining the info for multiple such
> entities, i.e. it is NOT a direct representation of the data entity).
>
> Example: We define Microsoft as a business entity in our own namespace and
> want to preserve a link to the established, browsable resource.
>
> foo:microsoft a gr:BusinessEntity;
>                       gr:legalName "Microsoft Corp.".
>
> Up to now, we generally use and recommend rdfs:seeAlso for the link from
> the data entity to the Web page URI, e.g.
>
> foo:microsoft a gr:BusinessEntity;
>                       gr:legalName "Microsoft Corp.";
>                        rdfs:seeAlso <http://www.microsoft.com/>.
>
> Note that we cannot simply do content negotiation (i.e. redirect http
> requests for html to http://www.microsoft.com), because of practical and
> theoretical reasons. Also, content negotiation is IMO no substitute for a
> traversable link from the data node to the HTML node in the graph of data).
>
> The initial motivation for rdfs:seeAlso was that it does not require
> importing a second ontology like FOAF, and I would also hold that using
> rdfs:seeAlso is, in principle, correct.
>
> However, due to the growing amount of links on the Web of Linked Data,
> rdfs:seeAlso is now being used so frequently that it has become too
> unspecific for our purpose.
> If there are 20+ rdfs:seeAlso links from an entity,  e.g. to images and
> other resources, it's hard for a user agent to spot the single one link that
> points to the Web page, e.g. for actually buying a product.
>
> Now, the two main candidate predicates for replacing rdfs:seeAlso are IMHO
>
> 1. foaf:topic
> and
> 2. foaf:page.
>
> I have seen many usages of foaf:topic in such scenarios, but from reading
> the FOAF spec, I think that foaf:page is much more appropriate.
>

It's not about being more "appropriate" really since there are inverse of
each other, follow the domain/range to know which one to use, see
http://xmlns.com/foaf/spec/#term_page


>
> Proposed Pattern:
>
> foo:microsoft a gr:BusinessEntity;
>                       gr:legalName "Microsoft Corp.";
>                       foaf:page <http://www.microsoft.com/>.
>
> foaf:topic could be used for linking back from the Web page URI to the data
> entity URI, e.g.
>
> <http://www.microsoft.com/> foaf:topic foo:microsoft.
>

foaf:topic domain is foaf:Document, range is owl:Thing, it works.


>
> What's your opinion on that? Will that work with your software
> applications? Or should we use foaf:topic instead? If so, in which
> direction?
>
> Alternative 1:
>
> foo:microsoft a gr:BusinessEntity;
>                       gr:legalName "Microsoft Corp.".
>
> <http://www.microsoft.com/> foaf:topic foo:microsoft.
>

ok.


>
> Alternative 2:
>
> foo:microsoft a gr:BusinessEntity;
>                       gr:legalName "Microsoft Corp.";
>                       foaf:topic <http://www.microsoft.com/>.
>
> I personally think that the second alternative is wrong, because the data
> entity does not describe the Web page, but vice versa.
>

Right, <http://www.microsoft.com/> is a foaf:Document, you should not use
this alternative.

Steph.


>
> Since this decision will be important for compatibility with SemWeb /
> Linkedata applications, I would be very thankful for your comments.
>
> Best wishes
>
> Martin Hepp
>
> --
>
> --
> --------------------------------------------------------------
> martin hepp
> e-business & web science research group
> universitaet der bundeswehr muenchen
>
> e-mail:  hepp@ebusiness-unibw.org
> phone:   +49-(0)89-6004-4217
> fax:     +49-(0)89-6004-4620
> www:     http://www.unibw.de/ebusiness/ (group)
>        http://www.heppnetz.de/ (personal)
> skype:   mfhepp twitter: mfhepp
>
> Check out GoodRelations for E-Commerce on the Web of Linked Data!
> =================================================================
>
> Project page:
> http://purl.org/goodrelations/
>
> Resources for developers:
> http://www.ebusiness-unibw.org/wiki/GoodRelations
>
> Webcasts:
> Overview - http://www.heppnetz.de/projects/goodrelations/webcast/
> How-to   - http://vimeo.com/7583816
>
> Recipe for Yahoo SearchMonkey:
> http://www.ebusiness-unibw.org/wiki/GoodRelations_and_Yahoo_SearchMonkey
>
> Talk at the Semantic Technology Conference 2009: "Semantic Web-based
> E-Commerce: The GoodRelations Ontology"
>
> http://www.slideshare.net/mhepp/semantic-webbased-ecommerce-the-goodrelations-ontology-1535287
>
> Overview article on Semantic Universe:
>
> http://www.semanticuniverse.com/articles-semantic-web-based-e-commerce-webmasters-get-ready.html
>
> Tutorial materials:
> ISWC 2009 Tutorial: The Web of Data for E-Commerce in Brief: A Hands-on
> Introduction to the GoodRelations Ontology, RDFa, and Yahoo! SearchMonkey
> http://www.ebusiness-unibw.org/wiki/Web_of_Data_for_E-Commerce_Tutorial_ISWC2009
>
>
>