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[Dbpedia-discussion] SKOS property in DBPedia

From: KANZAKI Masahide <mkanzaki@gm...> - 2008-01-24 03:16

Hi Richard,

It seems very strange for me to relate a DBPedia resource and its
category by skos:subject. Although its rdfs:domain is not defined, I
think skos:subject (and its super property dc:subject) is normally
used to relate a (creative) work and its subject, not a concept and
other concept, nor such real world thing as a person and a concept.

How do you think ?

08/01/24 Richard Cyganiak<richard@cyganiak.de>
> Masahide,
>
> On 17 Jan 2008, at 10:31, KANZAKI Masahide wrote:
> > of course, I love DBPedia :-)
> >
> > (though its use of SKOS properties is something questionable -- that's
> > another story)
>
> I'd love to hear it ;-)
>
> Especially with dbpedia-discussion@lists.sourceforge.net in CC ;-)

--
@fix : <http://www.kanzaki.com/ns/sig#> . <> :from [:name
"KANZAKI Masahide"; :nick "masaka"; :email "mkanzaki@gmail.com"].

Re: [Dbpedia-discussion] SKOS property in DBPedia

From: Richard Cyganiak <richard@cy...> - 2008-01-24 10:08

On 24 Jan 2008, at 03:16, KANZAKI Masahide wrote:
> It seems very strange for me to relate a DBPedia resource and its
> category by skos:subject. Although its rdfs:domain is not defined, I
> think skos:subject (and its super property dc:subject) is normally
> used to relate a (creative) work and its subject, not a concept and
> other concept, nor such real world thing as a person and a concept.

I agree that the most typical use of skos:subject is to relate
creative works and concepts.

We decided early on to model the Wikipedia category system using SKOS,
and I think it's a very good match. The only problem was: What
property to use for indexing DBpedia resources into their respective
categories?

We couldn't find any indication in the SKOS documentation that
skos:subject should be used *only* for creative works. I also asked on
the SKOS list if this was okay, and the consensus seemed to be that
it's a bit strange, but not illegal.

So we went with skos:subject.

Maybe there is a better choice? Do you have a suggestion for another,
more appropriate property to use in place of skos:subject?

Cheers,
Richard

>
>
>
> How do you think ?
>
> 08/01/24 Richard Cyganiak<richard@cyganiak.de>
>> Masahide,
>>
>> On 17 Jan 2008, at 10:31, KANZAKI Masahide wrote:
>>> of course, I love DBPedia :-)
>>>
>>> (though its use of SKOS properties is something questionable --
>>> that's
>>> another story)
>>
>> I'd love to hear it ;-)
>>
>> Especially with dbpedia-discussion@lists.sourceforge.net in CC ;-)
>
> --
> @fix : <http://www.kanzaki.com/ns/sig#> . <> :from [:name
> "KANZAKI Masahide"; :nick "masaka"; :email "mkanzaki@gmail.com"]. /> >
> -------------------------------------------------------------------------
> This SF.net email is sponsored by: Microsoft
> Defy all challenges. Microsoft(R) Visual Studio 2008.
> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
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> Dbpedia-discussion@lists.sourceforge.net /> > https://lists.sourceforge.net/lists/listinfo/dbpedia-discussion

Re: [Dbpedia-discussion] SKOS property in DBPedia

From: KANZAKI Masahide <mkanzaki@gm...> - 2008-01-24 11:06

2008/1/24, Richard Cyganiak:
> We couldn't find any indication in the SKOS documentation that
> skos:subject should be used *only* for creative works. I also asked on
> the SKOS list if this was okay, and the consensus seemed to be that
> it's a bit strange, but not illegal.

Well, there is no domain restriction for skos:subject, so it's 'legal'
to relate anything and skos:Concept with skos:subject, but sometimes
inappropriate. Let's think the following statement:

dbpedia:Tim_Berners-Lee skos:subject dbpedia:Category:Living_people .

I don't think it's good idea to say that "TimBL's subject (or topic)
is Living_people" although we can say that "TimBL is categorized as
Living_people". A person can be a subject of some works, and a person
may be interested in some topics, but I can't imagine that a person
has a subject or a topic ...

> Maybe there is a better choice? Do you have a suggestion for another,
> more appropriate property to use in place of skos:subject?

I've tried similar approach that used Wikipedia as PSI of a subject,
and used Wikipedia category as basis to categorize these subjects.
Since I couldn't find appropriate terms for this purpose, I defined
own vocabulary to describe them.
<http://purl.org/net/ns/wordmap#category> can be used to relate
DBPedia resource and its category, though the vocabulary is not well
known (so far ;-).

Or, since DBPedia already defined many terms for own project, it'd be
no problem to define one more property for category relationship.

best regards,
--
@fix : <http://www.kanzaki.com/ns/sig#> . <> :from [:name
"KANZAKI Masahide"; :nick "masaka"; :email "mkanzaki@gmail.com"].

Re: [Dbpedia-discussion] SKOS property in DBPedia

From: Richard Cyganiak <richard@cy...> - 2008-01-24 13:03

Hmmm, re-reading some of the SKOS docs I get the feeling that
skos:subject is indeed appropriate only for documents:

http://www.w3.org/TR/swbp-skos-core-guide/#secindexing
| These properties [including skos:subject] can be used for subject
| indexing of information resources on the web. Here 'subject indexing'
| means the same as 'indexing' as defined by Willpower Glossary.

The Willpower Glossary says:
| indexing: intellectual analysis of the subject matter of a document
| to identify the concepts resented in it, and allocation of the
| corresponding ferred terms to allow the information to be retrieved

So, skos:subject is intended for use on information resources, that is,
documents. DBpedia resources in general are not documents.

I'm logging this as a bug in the tracker. I think that a new property
in the DBpedia namespace is perhaps the simplest solution, e.g.
dbpedia:category.

Thoughts anyone?

Richard

On 24 Jan 2008, at 11:06, KANZAKI Masahide wrote:

> 2008/1/24, Richard Cyganiak:
>> We couldn't find any indication in the SKOS documentation that
>> skos:subject should be used *only* for creative works. I also asked
>> on
>> the SKOS list if this was okay, and the consensus seemed to be that
>> it's a bit strange, but not illegal.
>
> Well, there is no domain restriction for skos:subject, so it's 'legal'
> to relate anything and skos:Concept with skos:subject, but sometimes
> inappropriate. Let's think the following statement:
>
> dbpedia:Tim_Berners-Lee skos:subject dbpedia:Category:Living_people .
>
> I don't think it's good idea to say that "TimBL's subject (or topic)
> is Living_people" although we can say that "TimBL is categorized as
> Living_people". A person can be a subject of some works, and a person
> may be interested in some topics, but I can't imagine that a person
> has a subject or a topic ...
>
>> Maybe there is a better choice? Do you have a suggestion for another,
>> more appropriate property to use in place of skos:subject?
>
> I've tried similar approach that used Wikipedia as PSI of a subject,
> and used Wikipedia category as basis to categorize these subjects.
> Since I couldn't find appropriate terms for this purpose, I defined
> own vocabulary to describe them.
> <http://purl.org/net/ns/wordmap#category> can be used to relate
> DBPedia resource and its category, though the vocabulary is not well
> known (so far ;-).
>
> Or, since DBPedia already defined many terms for own project, it'd be
> no problem to define one more property for category relationship.
>
> best regards,
> --
> @fix : <http://www.kanzaki.com/ns/sig#> . <> :from [:name
> "KANZAKI Masahide"; :nick "masaka"; :email "mkanzaki@gmail.com"].

Re: [Dbpedia-discussion] SKOS property in DBPedia

From: Frederick Giasson <fred@fg...> - 2008-01-24 13:28

Hi Richard,

> I'm logging this as a bug in the tracker. I think that a new property
> in the DBpedia namespace is perhaps the simplest solution, e.g.
> dbpedia:category.
>

What is a category for DBPedia?

Answering to this question will tell you if it is the good thing to do
or not.

If one is answering that it is a Wikipedia Category, then I will answer
that it is not the good thing to do in my opinion.

If one ask me why? I would answer that it is become many of the
wikipedia categories are classes and in such a case why not defining
them as a Class, and not a "category" (that could be considered a class
for some sense of that class)?

What if a category is not a class but something else? It is where the
cleaning process is starting :)

Take care,

Fred

Re: [Dbpedia-discussion] SKOS property in DBPedia

From: KANZAKI Masahide <mkanzaki@gm...> - 2008-01-24 13:57

Hi Fred

2008/1/24, Frederick Giasson :
> If one ask me why? I would answer that it is become many of the
> wikipedia categories are classes and in such a case why not defining
> them as a Class, and not a "category" (that could be considered a class
> for some sense of that class)?

Wikipedia category is a classification, but not a Class in RDF/OWL
sense (in most cases).

For example, a category 'Internet_history' (taken from Tim Berners-Lee
example) has 'Internet' as its super category. It's maybe OK as
classification, but doesn't work as Classes, because
'Internet_history' cannot be a subClassOf 'Internet' (perhaps
subClassOf 'History').

There are such categories as 'Tokyo', which could be used as labes of
classification, but not even Concepts (or think it like 'Tokyo as
concept' ? sounds tricky).

I do support to use wikipedia concepts for useful information. Just
concern how they should be related to DBPedia resources.

best,

--
@fix : <http://www.kanzaki.com/ns/sig#> . <> :from [:name
"KANZAKI Masahide"; :nick "masaka"; :email "mkanzaki@gmail.com"].

Re: [Dbpedia-discussion] SKOS property in DBPedia

From: Richard Cyganiak <richard@cy...> - 2008-01-24 14:03

Fred,

On 24 Jan 2008, at 13:31, Frederick Giasson wrote:
> What is a category for DBPedia?
>
> Answering to this question will tell you if it is the good thing to
> do or not.
>
> If one is answering that it is a Wikipedia Category, then I will
> answer that it is not the good thing to do in my opinion.
>
> If one ask me why? I would answer that it is become many of the
> wikipedia categories are classes

No. The Wikipedia category system is simply not appropriate as a class
hierarchy. That's not a bug; it serves its purpose well, and the
Wikipedia community likes it that way. It is essentially a tagging
system, where tags themselves can be tagged. See [1] for an in-depth
analysis.

SKOS is an appropriate vocabulary for modelling the Wikipedia category
system. RDFS is not. Hence, we do need a property for indexing
arbitrary non-document resources into skos:Concepts.

(By the way: Yes, class hierarchies can be created from the Wikipedia
category system, e.g. by using cleanup heuristics and combining it
with other data sources such as WordNet. Research on this is ongoing
in the DBpedia project and elsewhere.)

Richard

[1] http://arxiv.org/abs/cs/0604036

>
> and in such a case why not defining them as a Class, and not a
> "category" (that could be considered a class for some sense of that
> class)?

> What if a category is not a class but something else? It is where
> the cleaning process is starting :)
>
>
>
>
>
> Take care,
>
>
> Fred

Re: [Dbpedia-discussion] SKOS property in DBPedia

From: Frederick Giasson <fred@fg...> - 2008-01-24 14:09

Hi Masahide,

>> If one ask me why? I would answer that it is become many of the
>> wikipedia categories are classes and in such a case why not defining
>> them as a Class, and not a "category" (that could be considered a class
>> for some sense of that class)?
>>
>
> Wikipedia category is a classification, but not a Class in RDF/OWL
> sense (in most cases).
>
>
You just hit the nail :)

You said it: in most cases.

In fact, Wikipedia categories can be many things: named entities,
concepts, relations, (something else?)

So, why defining all wikipedia "categories" as "categories"
(classification purposes) when it is *clearly* not the case?

In my point of view, it just make things worse. In case of ambiguity,
discard them, don't pollute the dataset with false assertions.

In would encourage, everyone on that list, to read and re-read the work
of Fabian on Yago:

http://www.mpi-inf.mpg.de/~suchanek/publications/yagotr.pdf

> For example, a category 'Internet_history' (taken from Tim Berners-Lee
> example) has 'Internet' as its super category. It's maybe OK as
> classification, but doesn't work as Classes, because
> 'Internet_history' cannot be a subClassOf 'Internet' (perhaps
> subClassOf 'History').
>

I think this would be a relation.
> There are such categories as 'Tokyo', which could be used as labes of
> classification, but not even Concepts (or think it like 'Tokyo as
> concept' ? sounds tricky).
>
>

Tricky, but it just found the gray area between a "subject concept" and
a "named entity" I think.

> I do support to use wikipedia concepts for useful information. Just
> concern how they should be related to DBPedia resources.
>

What is a "Wikipedia concept"? I mean, is it different from a "concept"?

How they should be related to DBPEdia resources?

With great care.

Take care,

Fred

Re: [Dbpedia-discussion] SKOS property in DBPedia

From: Frederick Giasson <fred@fg...> - 2008-01-24 14:14

Hi Richard,

> No. The Wikipedia category system is simply not appropriate as a class
> hierarchy. That's not a bug; it serves its purpose well, and the
> Wikipedia community likes it that way. It is essentially a tagging
> system, where tags themselves can be tagged. See [1] for an in-depth
> analysis.
>

Sure, but we are talking about the use of wikipedia categories in
dbpedia; I am not questionning the use of categories in WIkipedia.

> SKOS is an appropriate vocabulary for modelling the Wikipedia category
> system. RDFS is not. Hence, we do need a property for indexing
> arbitrary non-document resources into skos:Concepts.
>
RDFS is not in some case, but it is in some other.

> (By the way: Yes, class hierarchies can be created from the Wikipedia
> category system, e.g. by using cleanup heuristics and combining it
> with other data sources such as WordNet. Research on this is ongoing
> in the DBpedia project and elsewhere.)

Exactly what I am talking about. And as I said in my reply to Masahide:
should be handled with grat care.

Many others? For sure, there are more than 50 papers that talk about
that :) In multiple research groups around the globe.

The only thing I say is that it is neither black or white, but there are
much gray in there. And putting everything in the same bag doesn't help
making it more useful.

Take care,

Fred

Re: [Dbpedia-discussion] SKOS property in DBPedia

From: Bernard Vatant <bernard.vatant@mo...> - 2008-01-24 14:14

Hi Richard

See also the other thread about decation of skos:subject (I suggest
to close the current thread and follow-up on that one to avoid parallel
discussions)

Richard Cyganiak a écrit :
> Hmmm, re-reading some of the SKOS docs I get the feeling that
> skos:subject is indeed appropriate only for documents:
>
> http://www.w3.org/TR/swbp-skos-core-guide/#secindexing
> | These properties [including skos:subject] can be used for subject
> | indexing of information resources on the web. Here 'subject indexing'
> | means the same as 'indexing' as defined by Willpower Glossary.
>
> The Willpower Glossary says:
> | indexing: intellectual analysis of the subject matter of a document
> | to identify the concepts resented in it, and allocation of the
> | corresponding ferred terms to allow the information to be retrieved
>
Indeed, but the genral notion of resource has evolved in the history of
the Web from documents to more and more abstract resources. As you know,
I belong to people who consider that there is a continuum from physical
documents to abstract concepts, and any distinct limit between
"document", "information resource", "named entity", "concept" ... is
arbitrary.
So, if we want to avoid endless discussions about that, let's assume that

Everything is a resource
Everything (including concepts themselves) can be indexed by concepts
in order to be retrieved
A generic mechanism for that should encompass all resources

Indexing writers, musicians, buildings by art style, towns and countries
by used languages or religions, restaurants by food type etc ... make
sense whenever this is intended to retrieve those resources, not to
declare classes and attributes. So, using skos:subject for grouping and
retrieving DBpedia resources by Wikipedia categories makes perfect sense
to me. That said, I agree the example pointed out by Masahide can seem
weird.

dbpedia:Tim_Berners-Lee skos:subject dbpedia:Category:Living_people

... but, as said in the other thread, not because of the use of
skos:subject, but because of the strangeness of the Wikipedia category
"Living people", which unfortunately tends to be not very reliable, and
subject to permanent modification ...

That said, it is perfectly functional : it supports queries retrieving
all people indexed in this category. And you don't ask more to such a
declaration.
> So, skos:subject is intended for use on information resources, that is,
> documents. DBpedia resources in general are not documents.
>
See above. Don't put your foot on this slippery slope ...
> I'm logging this as a bug in the tracker. I think that a new property
> in the DBpedia namespace is perhaps the simplest solution, e.g.
> dbpedia:category.
>
Well, I don't think it's a good idea. How will you federate this
property with other indexing pointers?
> Thoughts anyone?
>
>
You got some :-)

Cheers

Bernard
> Richard
>
>
>
> On 24 Jan 2008, at 11:06, KANZAKI Masahide wrote:
>
>
>> 2008/1/24, Richard Cyganiak:
>>
>>> We couldn't find any indication in the SKOS documentation that
>>> skos:subject should be used *only* for creative works. I also asked
>>> on
>>> the SKOS list if this was okay, and the consensus seemed to be that
>>> it's a bit strange, but not illegal.
>>>
>> Well, there is no domain restriction for skos:subject, so it's 'legal'
>> to relate anything and skos:Concept with skos:subject, but sometimes
>> inappropriate. Let's think the following statement:
>>
>> dbpedia:Tim_Berners-Lee skos:subject dbpedia:Category:Living_people .
>>
>> I don't think it's good idea to say that "TimBL's subject (or topic)
>> is Living_people" although we can say that "TimBL is categorized as
>> Living_people". A person can be a subject of some works, and a person
>> may be interested in some topics, but I can't imagine that a person
>> has a subject or a topic ...
>>
>>
>>> Maybe there is a better choice? Do you have a suggestion for another,
>>> more appropriate property to use in place of skos:subject?
>>>
>> I've tried similar approach that used Wikipedia as PSI of a subject,
>> and used Wikipedia category as basis to categorize these subjects.
>> Since I couldn't find appropriate terms for this purpose, I defined
>> own vocabulary to describe them.
>> <http://purl.org/net/ns/wordmap#category> can be used to relate
>> DBPedia resource and its category, though the vocabulary is not well
>> known (so far ;-).
>>
>> Or, since DBPedia already defined many terms for own project, it'd be
>> no problem to define one more property for category relationship.
>>
>> best regards,
>> --
>> @fix : <http://www.kanzaki.com/ns/sig#> . <> :from [:name
>> "KANZAKI Masahide"; :nick "masaka"; :email "mkanzaki@gmail.com"]. /> >>
>
>
> -------------------------------------------------------------------------
> This SF.net email is sponsored by: Microsoft
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>
>
>

--

*Bernard Vatant
*Knowledge Engineering
----------------------------------------------------
*Mondeca**
*3, cité 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>
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Re: [Dbpedia-discussion] SKOS property in DBPedia

From: Richard Cyganiak <richard@cy...> - 2008-01-24 15:28

On 24 Jan 2008, at 14:09, Frederick Giasson wrote:
> In fact, Wikipedia categories can be many things: named entities,
> concepts, relations, (something else?)

They certainly all are skos:Concepts. SKOS was created for the purpose
of resenting exactly that sort of things -- thesauri, taxonomies,
and tagging schemes -- in RDF.

> So, why defining all wikipedia "categories" as
> "categories" (classification purposes) when it is *clearly* not the
> case?

Some of the categories might conceivably be modelled as other things
as skos:Concepts. That doesn't change the fact that *all* of them can
be modelled as skos:Concepts.

> In my point of view, it just make things worse. In case of
> ambiguity, discard them, don't pollute the dataset with false
> assertions.

What false assertions?

> In would encourage, everyone on that list, to read and re-read the
> work of Fabian on Yago:
>
> http://www.mpi-inf.mpg.de/~suchanek/publications/yagotr.pdf

It is true that a lot of interesting things can be done on top of the
Wikipedia categories.

This doesn't change the fact that there is value in a faithful RDF
resentation of the Wikipedia category system, warts and all, using
an appropriate RDF vocabulary. That's what we have done so far.

Richard

>
>
>
>
>
>
>> For example, a category 'Internet_history' (taken from Tim Berners-
>> Lee
>> example) has 'Internet' as its super category. It's maybe OK as
>> classification, but doesn't work as Classes, because
>> 'Internet_history' cannot be a subClassOf 'Internet' (perhaps
>> subClassOf 'History').
>>
>
> I think this would be a relation.
>> There are such categories as 'Tokyo', which could be used as labes of
>> classification, but not even Concepts (or think it like 'Tokyo as
>> concept' ? sounds tricky).
>>
>>
>
> Tricky, but it just found the gray area between a "subject concept"
> and a "named entity" I think.
>
>> I do support to use wikipedia concepts for useful information. Just
>> concern how they should be related to DBPedia resources.
>>
>
> What is a "Wikipedia concept"? I mean, is it different from a
> "concept"?
>
>
> How they should be related to DBPEdia resources?
>
> With great care.
>
>
> Take care,
>
> Fred
>

Re: [Dbpedia-discussion] SKOS property in DBPedia

From: Frederick Giasson <fred@fg...> - 2008-01-24 15:49

Hi Richard,
>> In fact, Wikipedia categories can be many things: named entities,
>> concepts, relations, (something else?)
>
> They certainly all are skos:Concepts. SKOS was created for the purpose
> of resenting exactly that sort of things -- thesauri, taxonomies,
> and tagging schemes -- in RDF.
>
Yes I know what SKOS is used for.
>> So, why defining all wikipedia "categories" as "categories"
>> (classification purposes) when it is *clearly* not the case?
>
> Some of the categories might conceivably be modelled as other things
> as skos:Concepts. That doesn't change the fact that *all* of them can
> be modelled as skos:Concepts.
>

You said *all*, so you mean that:

A Named Entity
A Concept
A Relation

are all skos:Concept?

so, each of these things are: An abstract idea or notion; a unit of thought.

Could I ask you how you would define a named entity? Also, what about
the Wikipedia Category "Elvis"?

I do I agree that there are gray areas between named entities and
concepts. However, is it safe to say that *all* named entities are concept?

I don't say I am right here, I only ask questions to make things clearer.

>> In my point of view, it just make things worse. In case of ambiguity,
>> discard them, don't pollute the dataset with false assertions.
>
> What false assertions?

Saying that all named entities are skos:Concept. Everything depends on
how you define things....

>> In would encourage, everyone on that list, to read and re-read the
>> work of Fabian on Yago:
>>
>> http://www.mpi-inf.mpg.de/~suchanek/publications/yagotr.pdf
>
> It is true that a lot of interesting things can be done on top of the
> Wikipedia categories.

Really depends what for. For ontological purposes? I would say no, or at
last barely useful (as Fabian would say).

For other purposes? Sure it does, we only have to check on Wikipedia :)

> This doesn't change the fact that there is value in a faithful RDF
> resentation of the Wikipedia category system, warts and all, using
> an appropriate RDF vocabulary. That's what we have done so far.
What is the value you give to it? (I am just asking the question here, I
am not saying that there is none; I only want to know what is the value
DBPedia have from these categories). What is the added value.

Take care,

Fred

Re: [Dbpedia-discussion] SKOS property in DBPedia

From: Richard Cyganiak <richard@cy...> - 2008-01-24 16:40

On 24 Jan 2008, at 15:49, Frederick Giasson wrote:
>>> So, why defining all wikipedia "categories" as =20
>>> "categories" (classification purposes) when it is *clearly* not =20
>>> the case?
>>
>> Some of the categories might conceivably be modelled as other =20
>> things as skos:Concepts. That doesn't change the fact that *all* of =20=

>> them can be modelled as skos:Concepts.
>
> You said *all*, so you mean that:
>
> A Named Entity
> A Concept
> A Relation
>
> are all skos:Concept?

No.

I said that each Wikipedia category is a skos:Concept. The Wikipedia =20
category system is a concept scheme, in the SKOS sense. There are no =20
=93named entities=94, or =93relations=94 in a concept scheme.

The category "Berlin" is still a concept. It might have a =20
corresponding named entity somewhere, but that's another story. The =20
named entity is not part of the concept scheme.

Richard

>
>
> so, each of these things are: An abstract idea or notion; a unit of =20=

> thought.
>
>
> Could I ask you how you would define a named entity? Also, what =20
> about the Wikipedia Category "Elvis"?
>
> I do I agree that there are gray areas between named entities and =20
> concepts. However, is it safe to say that *all* named entities are =20
> concept?
>
>
> I don't say I am right here, I only ask questions to make things =20
> clearer.
>
>>> In my point of view, it just make things worse. In case of =20
>>> ambiguity, discard them, don't pollute the dataset with false =20
>>> assertions.
>>
>> What false assertions?
>
> Saying that all named entities are skos:Concept. Everything depends =20=

> on how you define things....
>
>>> In would encourage, everyone on that list, to read and re-read the =20=

>>> work of Fabian on Yago:
>>>
>>> http://www.mpi-inf.mpg.de/~suchanek/publications/yagotr.pdf
>>
>> It is true that a lot of interesting things can be done on top of =20
>> the Wikipedia categories.
>
> Really depends what for. For ontological purposes? I would say no, =20
> or at last barely useful (as Fabian would say).
>
> For other purposes? Sure it does, we only have to check on =20
> Wikipedia :)
>
>> This doesn't change the fact that there is value in a faithful RDF =20=

>> resentation of the Wikipedia category system, warts and all, =20
>> using an appropriate RDF vocabulary. That's what we have done so far.
> What is the value you give to it? (I am just asking the question =20
> here, I am not saying that there is none; I only want to know what =20
> is the value DBPedia have from these categories). What is the added =20=

> value.
>
>
>
> Take care,
>
>
> Fred

Re: [Dbpedia-discussion] SKOS property in DBPedia

From: Frederick Giasson <fred@fg...> - 2008-01-24 16:48

Hi Richard,

My last answer to that thread since it could evolves that way for years
:) It is all about definitions and our views of these things

> I said that each Wikipedia category is a skos:Concept. The Wikipedia
> category system is a concept scheme, in the SKOS sense. There are no
> “named entities”, or “relations” in a concept scheme.
>

It is what I was saying: a Wikipedia Category can be: a named entity
(Elvis), a concept, a relation, and possibly other things.

So it is why I was making sure that all these three things where
concepts for you (because you said *all*). However it seems clear now
that it is not (at my standpoint, and at yours).

> The category "Berlin" is still a concept. It might have a
> corresponding named entity somewhere, but that's another story. The
> named entity is not part of the concept scheme.
Totally agree that Berlin is both a named entity and a concept. It is
part of the gray area between concepts and named entities.

Take care,

Fred

Re: [Dbpedia-discussion] SKOS property in DBPedia

From: Kingsley Idehen <kidehen@op...> - 2008-01-24 17:15

Frederick Giasson wrote:
> Hi Richard,
>
>>> In fact, Wikipedia categories can be many things: named entities,
>>> concepts, relations, (something else?)
>>>
>> They certainly all are skos:Concepts. SKOS was created for the purpose
>> of resenting exactly that sort of things -- thesauri, taxonomies,
>> and tagging schemes -- in RDF.
>>
>>
> Yes I know what SKOS is used for.
>
>>> So, why defining all wikipedia "categories" as "categories"
>>> (classification purposes) when it is *clearly* not the case?
>>>
>> Some of the categories might conceivably be modelled as other things
>> as skos:Concepts. That doesn't change the fact that *all* of them can
>> be modelled as skos:Concepts.
>>
>>
>
> You said *all*, so you mean that:
>
> A Named Entity
> A Concept
> A Relation
>
> are all skos:Concept?
>
> so, each of these things are: An abstract idea or notion; a unit of thought.
>
>
> Could I ask you how you would define a named entity? Also, what about
> the Wikipedia Category "Elvis"?
>
> I do I agree that there are gray areas between named entities and
> concepts. However, is it safe to say that *all* named entities are concept?
>

Fred,

YES.

Everything in DBpedia is a skos:Concept (imho).
>
> I don't say I am right here, I only ask questions to make things clearer.
>
>
>>> In my point of view, it just make things worse. In case of ambiguity,
>>> discard them, don't pollute the dataset with false assertions.
>>>
>> What false assertions?
>>
>
> Saying that all named entities are skos:Concept. Everything depends on
> how you define things....
>
Well I believe all things are units of perception that provide routes to
comhension. Thus, all perceptions are Concepts :-)

We get this right and then inject MOAT for the tags / categories and
things get a little better.

As you said, DBpedia 3.0 should leverage Yago better this time around.

Kingsley
>
>>> In would encourage, everyone on that list, to read and re-read the
>>> work of Fabian on Yago:
>>>
>>> http://www.mpi-inf.mpg.de/~suchanek/publications/yagotr.pdf
>>>
>> It is true that a lot of interesting things can be done on top of the
>> Wikipedia categories.
>>
>
> Really depends what for. For ontological purposes? I would say no, or at
> last barely useful (as Fabian would say).
>
> For other purposes? Sure it does, we only have to check on Wikipedia :)
>
>
>> This doesn't change the fact that there is value in a faithful RDF
>> resentation of the Wikipedia category system, warts and all, using
>> an appropriate RDF vocabulary. That's what we have done so far.
>>
> What is the value you give to it? (I am just asking the question here, I
> am not saying that there is none; I only want to know what is the value
> DBPedia have from these categories). What is the added value.
>
>
>
> Take care,
>
>
> Fred
>
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>

--

Regards,

Kingsley Idehen Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO
OpenLink Software Web: http://www.openlinksw.com

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