Re: [Dbpedia-discussion] DBtax questions

Hi Magnus and thanks for your interest,

Generally speaking, the challenge of assigning "correct" types to 
entities is always a highly subjective task.
 From a strictly linguistic point of view, a classification taxonomy is 
itself a very debatable way to describe the semantics of content 
expressed in natural language: one should always keep in mind contextual 
pieces of information to deeply understand the sense of e.g., some 
Wikipedia article.

Said that, the main goal of DBTax is to assign as many types as 
possible, provided that they are different from owl#Thing.
In this way, we can cluster entities with more meaningful types and 
query the knowledge base accordingly.

Of course, you can say that owl#Thing has 100% coverage, but does it 
make sense?
The claimed 99% stems instead from a *set* of more specific types.
Then high recall comes with a precision cost.

On 9/17/15 4:04 PM, Magnus Knuth wrote:
> One structural problem I recognized when seeing the approach [http://jens-lehmann.org/files/2015/semantics_dbtax.pdf], is that there is in most (non-complex) categories an article having exactly the same name, e.g. dbr:President dc:subject dbc:President. And indeed these resources are typed accordingly, e.g. http://it.dbpedia.org/resource/Presidente is a dbtax:President and http://it.dbpedia.org/resource/Pagoda is dbtax:Pagoda.
That is obvious for a human, but is it the same for an algorithm? :-)
>
> A type coverage of more than 99 percent is very suspicious, because I’d expect much more resources in DBpedia not type-able. Why? A lot of articles in DBpedia describe very abstract concepts, e.g. Liberty, Nationality, Social_inequality (well, you have the class dbtax:Concept, but what is on the other hand not a concept?), or they describe classes by their selves, e.g. President, Country, Person, Plane (well, you have the class dbtax:Classification, but it is not used as such [http://it.dbpedia.org/sparql?default-graph-uri=&query=SELECT+*+%7B%3Fres+a+%3Chttp%3A%2F%2Fdbpedia.org%2Fdbtax%2FClassification%3E%7D&format=text%2Fhtml&debug=on]). For some articles it is arguable whether they are instance or class, e.g. Volkswagen_Polo, Horse.
>
> I see that the classes you extracted are truly valuable for enriching the DBpedia ontology, but it obviously needs some tidy up and disambiguate efforts.
I completely agree: I think we should merge DBTax into the DBpedia 
ontology mappings wiki to do so.
BTW, DBTax overlaps with the DBpedia ontology by more than 20%.

Cheers!
>
> Best regards and thanks for this work.
> Magnus
>
> Am 07.09.2015 um 15:33 schrieb Marco Fossati <hell.j.fox@gmail.com>:
>
>> Hi Vladimir and thanks for the feedback!
>>
>> On 9/7/15 2:57 PM, Vladimir Alexiev wrote:
>>> Hi Marco!
>>>
>>> A couple of questions about DBtax:
>>> - could you publish the ontology in a resolvable way?
>>>    E.g. http://it.dbpedia.org/resource/Bitcoin/html has rdf:type http://dbpedia.org/dbtax/Term but that doesn’t resolve.
>> Sure, it's in the list of things to be done.
>>> - are there definitions of the classes?
>> Since DBTax is an automatic approach, it is difficult to automatically
>> generate human-readable definitions.
>> I believe this can be crowdsourced to the DBpedia mappings wiki, what fo
>> you think?
>>>    E.g. Bitcoin has these classes, but I think those marked with !! are wrong and those with ?? are hard to tell before we have a definition for them
>>> dbtax: Page !!
>>> dbtax: Article !!
>>> dbtax: Protocol
>>> dbtax: Communication
>>> dbtax: Term ??
>>> dbtax: Payment
>>>
>>> Also looking in http://it.dbpedia.org/downloads/dbtax/T-Box.ttl, it's hard to tell what these mean:
>>>
>>> dbtax:Center  rdfs:label  "Center"@en ; rdfs:subClassOf  dbtax:Art .
>>> dbtax:Pagoda  rdfs:label  "Pagoda"@en ; rdfs:subClassOf  dbtax:Art .
>>> dbtax:Term  rdfs:label   "Term"@en ; rdfs:subClassOf  dbtax:Art .
>>>
>>> Cheers!
>>>
>> Cheers,
>> --
>> Marco Fossati
>> http://about.me/marco.fossati
>> Twitter: @hjfocs
>> Skype: hell_j
>>
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-- 
Marco Fossati
http://about.me/marco.fossati
Twitter: @hjfocs
Skype: hell_j

Received on Thursday, 17 September 2015 15:26:26 UTC