Re: Drilling into the LOD Cloud
Hummm, sorry. When talking about classes it does make sense ;) Or even skos:concepts ( which we can declared to belong to a given vocab, for example ). ( have been working with instance data for too long ). This might call for a way to make statements about a specific IRI, but that would require tertiary relations or some syntactic convention... sounds like going the wrong way. But no worse than the inferencing complexity that would arise from discarding owl:sameAs as a simple conceptual bridge between vocabularies. Sounds like a prob indeed. Best, A On Mon, Sep 29, 2008 at 1:16 AM, Aldo Bucchi [EMAIL PROTECTED] wrote: I think you're overlooking something If you're using dc:author to state http://dbpedia.org/resource/R%C3%B6yksopp dc:author example:me ( which translates to: I *created Royksopp*, the music band ) And then Umbel states that *they created* the music band ( I made this up for the example ). http://umbel.org/umbel/ne/wikipedia/R%C3%B6yksopp dc:author ex:someoneElse . you will indeed run into problems when equating the two IDs. http://dbpedia.org/resource/R%C3%B6yksopp owl:sameAs http://umbel.org/umbel/ne/wikipedia/R%C3%B6yksopp But, AFAIK, this is *incorrect usage of dc:author* and not a design flaw re. owl:sameAs. Luckily, neither UMBEL nor DBpedia seem to be using dc:author incorrectly. Authorship metadata should not be attached to the ID for the concept, but to the vocabulary namespace or through other indirection. Which brings up another point: how do you state that a URI belongs to a given vocabulary. - URI opaqueness plays against here - is this really something we want/need? - ... If what you intend to equate is a document ( which usually have dc:* metadata ) with another doc that has different metadata, stop and rethink it. You might be wanting to equate the concepts they reference. A On Sun, Sep 28, 2008 at 6:30 PM, Damian Steer [EMAIL PROTECTED] wrote: On 28 Sep 2008, at 19:01, Kingsley Idehen wrote: Dan Brickley wrote: Kingsley Idehen wrote: Then between UMBEL and OpenCyc: 1. owl:sameAs 2. owl:equivalentClass If these thingies are owl:sameAs, then presumably they have same IP-related characteristics, owners, creation dates etc? Does that mean Cycorp owns UMBEL? Dan, No, it implies that in the UMBEL data space you have equivalence between Classes used to define UMBEL subject concepts (subject matter entities) and OpenCyc. I think Dan's point is that owl:sameAs is a very strong statement, as illustrated by the ownership question. If opencyc:Motorcyle owl:equivalentClass umbel:Motorcycle then they have the same extension. Informally, any use you make of one as a class can be replaced by the other without changing the meaning of the whole. However if the are owl:sameAs they name the same thing, so dc:creationDate, dc:creator, cc:license, rdfs:isDefinedBy etc etc are the same for each, which strike me as unhelpful side effects. owl:equivalentClass is the vocabulary mappers' friend :-) Damian -- Aldo Bucchi +56 9 7623 8653 skype:aldo.bucchi twitter:aldonline http://aldobucchi.com/ http://univrz.com/ -- Aldo Bucchi +56 9 7623 8653 skype:aldo.bucchi twitter:aldonline http://aldobucchi.com/ http://univrz.com/
RE: RDFa in Wikipedia
hi jason, are you talking about tagging wikipedia articles or more about tagging other content with wikipedia URIs? best-- --cs -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: 27 September 2008 23:59 To: public-lod@w3.org Subject: RDFa in Wikipedia Some of the biggest linked datasets are derived from Wikipedia and semantic URIs are generated from article names. Wouldn't it make sense to develop a MediaWiki plugin (or core enhancement) that allows tagging of an article with a URI instead? Ideally you could tag any arbitrary content with the 'about' attribute, etc (a full featured RDFa plugin). Though tagging just the main content div would be a great start. Maybe it's as simple as a text box at the bottom of the article edit screen. Then we would just need to convince Mr. Wales to enable it on Wikipedia and we would have more robust subject mapping. Thoughts? Anyone familiar with MediaWiki have free cycles? :) Jason http://www.bbc.co.uk/ This e-mail (and any attachments) is confidential and may contain personal views which are not the views of the BBC unless specifically stated. If you have received it in error, please delete it from your system. Do not use, copy or disclose the information in any way nor act in reliance on it and notify the sender immediately. Please note that the BBC monitors e-mails sent or received. Further communication will signify your consent to this.
Re: Drilling into the LOD Cloud
On 29 Sep 2008, at 00:51, Peter Ansell wrote: That is fine for classes, but how do you map individuals without metadata side-effects? The simple answer is you can't, at least in general. The trick with equivalentClass (and property) is that it takes equivalence with respect to a particular facet of the individual: its 'class-ness'. See also OWL 2 punning (as far as I understand it), where you'd think about [X qua class] and [X qua individual]. For a generic individual we have no facets. Now there's not necessarily a problem here. There are plenty of perfectly good uses for sameAs: foo:Tony_Blair owl:sameAs bar:Tony_Blair. But what about foo:Gordon_Brown owl:sameAs bar:PM_of_UK? foo:Geo_China owl:sameAs bar:PRC? There's a huge literature about these issues, which ought to be warning enough that there's no simple solution. And a neutral term equivalentTo strikes me as virtually useless. So go for the easy patches, things like sameConceptAs and the frbr-ish sameWorkAs. They cover a lot of what we want to do. I could see sameGeoRegion having some utility in the future, and no doubt others can chip in more. These are my Monday morning thoughts, so be warned. Damian
Re: Drilling into the LOD Cloud
On 29 Sep 2008, at 05:16, Aldo Bucchi wrote: I think you're overlooking something If you're using dc:author to state http://dbpedia.org/resource/R%C3%B6yksopp dc:author example:me ( which translates to: I *created Royksopp*, the music band ) And then Umbel states that *they created* the music band ( I made this up for the example ). http://umbel.org/umbel/ne/wikipedia/R%C3%B6yksopp dc:author ex:someoneElse . you will indeed run into problems when equating the two IDs. http://dbpedia.org/resource/R%C3%B6yksopp owl:sameAs http://umbel.org/umbel/ne/wikipedia/R%C3%B6yksopp But, AFAIK, this is *incorrect usage of dc:author* and not a design flaw re. owl:sameAs. Yes, this is incorrect usage of the property. (I presume you mean dc:creator.) Luckily, neither UMBEL nor DBpedia seem to be using dc:author incorrectly. Authorship metadata should not be attached to the ID for the concept, but to the vocabulary namespace or through other indirection. What we usually do: We attach the metadata to the *document* that contains the *description* of the entity. So, in the DBpedia case the authorship information would be attached to the URI of the RDF document describing the band: http://dbpedia.org/data/R%C3%B6yksopp and not to the band's identifier. Multiple datasets can of course talk about the same band, but they will do so in different documents, and the different documents will have different metadata. This is the Named Graph model of metadata management. It works very well with Linked Data, but it's less clear how to apply it best to SPARQL-accessible RDF data. Which brings up another point: how do you state that a URI belongs to a given vocabulary. I'm not convinced that this is a useful thing to do. When defining RDFS/OWL terms, you can use rdfs:isDefinedBy to connect the class/ property to the defining RDFS/OWL document. - URI opaqueness plays against here - is this really something we want/need? - ... If what you intend to equate is a document ( which usually have dc:* metadata ) with another doc that has different metadata, stop and rethink it. You might be wanting to equate the concepts they reference. Yes exactly, nicely put. Yours, Richard A On Sun, Sep 28, 2008 at 6:30 PM, Damian Steer [EMAIL PROTECTED] wrote: On 28 Sep 2008, at 19:01, Kingsley Idehen wrote: Dan Brickley wrote: Kingsley Idehen wrote: Then between UMBEL and OpenCyc: 1. owl:sameAs 2. owl:equivalentClass If these thingies are owl:sameAs, then presumably they have same IP-related characteristics, owners, creation dates etc? Does that mean Cycorp owns UMBEL? Dan, No, it implies that in the UMBEL data space you have equivalence between Classes used to define UMBEL subject concepts (subject matter entities) and OpenCyc. I think Dan's point is that owl:sameAs is a very strong statement, as illustrated by the ownership question. If opencyc:Motorcyle owl:equivalentClass umbel:Motorcycle then they have the same extension. Informally, any use you make of one as a class can be replaced by the other without changing the meaning of the whole. However if the are owl:sameAs they name the same thing, so dc:creationDate, dc:creator, cc:license, rdfs:isDefinedBy etc etc are the same for each, which strike me as unhelpful side effects. owl:equivalentClass is the vocabulary mappers' friend :-) Damian -- Aldo Bucchi +56 9 7623 8653 skype:aldo.bucchi twitter:aldonline http://aldobucchi.com/ http://univrz.com/
Re: Drilling into the LOD Cloud
Hi all, First of all, I think that this thread is going out of control and some things have to be keep into mind when we talk about this stuff. Then between UMBEL and OpenCyc: 1. owl:sameAs 2. owl:equivalentClass If these thingies are owl:sameAs, then presumably they have same IP- related characteristics, owners, creation dates etc? Does that mean Cycorp owns UMBEL? Dan, No, it implies that in the UMBEL data space you have equivalence between Classes used to define UMBEL subject concepts (subject matter entities) and OpenCyc. Exact Damian, does that mean Cycorp owns UMBEL? : no. Dan wanted to show the strongness of the sameAs property with such a conclusion But the current fact is that UMBEL is a subset of OpenCyc (that is a subset of Cyc) where each UMBEL subject concept is an equivalentClass to a OpenCyc class. No sameAs relationship exists between umbel subject concepts and opencyc classes: everything happen at the class level. Now, what happen for UMBEL named entities? (invididual of classes). Some UMBEL named entities are sameAs dbpedia resources, yago resources, etc. However, the question is: does that mean that dbpedia or yago own umbel named entities? No. One set of named entities that describes named entities that appear on Wikipedia (and another one describe named entities described in the john peel sessions dataset from the bbc). On its side, DBpedia has done the same thing: it described individual of classes that appear on Wikipedia. So, if a sameAs statement is done between the UMBEL named entity (that is an individual of a class; so a candidate to use sameAs) that describe Abraham Lincoln for example, is sameAs, DBPedia's resource describing Abraham_Lincoln; does that mean that the meta data that describe the creator of the description of the resource is the same too? No since as other said on this thread: this meta-data would be described as its own resource. In any case, sameAs is a really strong statement to link instances of classes together. It is why we introduced the property umbel:isLike in umbel for example (still a test and feedbacks are welcome :) ) Thanks, Take care, Fred
Re: Drilling into the LOD Cloud
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 [sorry, forgot to reply-all] Peter Ansell wrote: | That is fine for classes, but how do you map individuals without metadata side-effects? Looking at my previous answer again I think I should take another run at this :-) One way of thinking about equivalence is in terms of substitution: if :x :equiv :y when is it safe to substitute :x with :y? The default is: it's not safe (obviously). :x equivalentClass :y - safe when used as a class (e.g. rdf:type :x) :x sameAs :y - always safe (watch out!) :x sameConceptAs :y - safe in subject positions :x sameWorkAs :y - safe for author, creation date :x sameManifestationAs :y - safe for the the above, and length (?) Does that help? Damian -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFI4NdRAyLCB+mTtykRAppqAJ9kzkWgcWt0zeWfWdMfWwqtdhoblwCeNCWH 54J20+PaNd1xmCmcFLs9DN8= =/gW2 -END PGP SIGNATURE-
Re: Drilling into the LOD Cloud
On Mon, Sep 29, 2008 at 2:08 PM, Dan Brickley [EMAIL PROTECTED] wrote: Damian Steer wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 [sorry, forgot to reply-all] Peter Ansell wrote: | That is fine for classes, but how do you map individuals without metadata side-effects? Looking at my previous answer again I think I should take another run at this :-) One way of thinking about equivalence is in terms of substitution: if :x :equiv :y when is it safe to substitute :x with :y? The default is: it's not safe (obviously). :x equivalentClass :y - safe when used as a class (e.g. rdf:type :x) :x sameAs :y - always safe (watch out!) :x sameConceptAs :y - safe in subject positions do you mean subject in the 'topic, dc:subject' sense, rather than subject/predicate/object sense? On first reading I thought you meant the latter, which would be problematic since any inverse of property can flip values into 'object' role. So assuming the former, I quite agree. Also thanks for expanding on what I meant. I was indeed picking a strong example to emphasise my (under articulated) case. Using an owl:sameAs claim between independently developed classes and properties is almost always misleading, confusing and untrue. So yup I agree that application-specific properties such as these are often more useful. Also btw folks there is no such thing as dc:author. It was changed in the mid-late 1990s to be dc:creator, so as to better cover non-written creations such as images, museum artifacts etc. So best to avoid/fix it in mail threads before 'dc:author' ends up getting mentioned in books etc. Oops. Made a quick search and I don't use author anywhere in my codebase ( I use creator ). But for some reason it is still sticking in my mind ( band, music, author ) If it shows up in a book I'll feel really guilty, as the material author of that crime ( or should I say creator )... This brings up another point ( re. retroactive edition ). Why haven't we found a replacement for mailing lists? Dog fooding anyone? ( rhetoric question perhaps. don't reply on this thread or it will go seriously off topic ). Thx, A cheers, Dan :x sameWorkAs :y - safe for author, creation date :x sameManifestationAs :y - safe for the the above, and length (?) Does that help? Damian -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFI4NdRAyLCB+mTtykRAppqAJ9kzkWgcWt0zeWfWdMfWwqtdhoblwCeNCWH 54J20+PaNd1xmCmcFLs9DN8= =/gW2 -END PGP SIGNATURE- -- Aldo Bucchi +56 9 7623 8653 skype:aldo.bucchi twitter:aldonline http://aldobucchi.com/ http://univrz.com/
Re: Drilling into the LOD Cloud
This is definitely too late, but still.. Have you seen http://der-mo.net/ 's visualizations? On Mon, Sep 22, 2008 at 6:43 AM, Ed Summers [EMAIL PROTECTED] wrote: I am doing a presentation (tomorrow) on lcsh.info at DC2008, and of course (hat tip to PaulMiller) I'm using the LOD Cloud to illustrate how you all actually putting RDF to work. While the LOD Cloud is great for visualizing the different data sets that are getting linked together, I was wondering if anyone happens to have some visualizations of the type of links that exist between resources in the LOD Cloud. I guess what I'm thinking of is the usual graph illustration with nodes, arcs, etc -- with resource URIs that live in different namespaces: geonames, dbpedia, etc ... I'd like to illustrate the importance of those linking assertions. If you have something handy, I'd love to use it, and spend more time drinking beer here in Berlin :-) //Ed -- Aldo Bucchi +56 9 7623 8653 skype:aldo.bucchi twitter:aldonline http://aldobucchi.com/ http://univrz.com/
Re: RDFa in Wikipedia
I was talking about tagging wikipedia articles with a subject (UMBEL or Open GUID, e.g.) I did see the Semantic-MediaWiki project, but that is more geared towards specific ontologies. There was a student recently working on an RDFa plugin for it [1], but not sure how extractable that is to base MediaWiki. There was also a student submission to the SWIKIG group that did not receive any responses. Might be out of date. 1. http://sourceforge.net/mailarchive/message.php?msg_id=DC7AB12E-3941-43E3-BB84-408802AA3C7D%40gmail.com 2. http://www.aifb.uni-karlsruhe.de/pipermail/swikig/2007-July/000427.html Chris Sizemore wrote: hi jason, are you talking about tagging wikipedia articles or more about tagging other content with wikipedia URIs? best-- --cs -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: 27 September 2008 23:59 To: public-lod@w3.org Subject: RDFa in Wikipedia Some of the biggest linked datasets are derived from Wikipedia and semantic URIs are generated from article names. Wouldn't it make sense to develop a MediaWiki plugin (or core enhancement) that allows tagging of an article with a URI instead? Ideally you could tag any arbitrary content with the 'about' attribute, etc (a full featured RDFa plugin). Though tagging just the main content div would be a great start. Maybe it's as simple as a text box at the bottom of the article edit screen. Then we would just need to convince Mr. Wales to enable it on Wikipedia and we would have more robust subject mapping. Thoughts? Anyone familiar with MediaWiki have free cycles? :) Jason http://www.bbc.co.uk/ This e-mail (and any attachments) is confidential and may contain personal views which are not the views of the BBC unless specifically stated. If you have received it in error, please delete it from your system. Do not use, copy or disclose the information in any way nor act in reliance on it and notify the sender immediately. Please note that the BBC monitors e-mails sent or received. Further communication will signify your consent to this.
