Re: ANN: Sparallax! - Browse sets of things together (now those on your SPARQL endpoint)

[Alan Ruttenberg]

Congratulations on doing this, and thanks! Parallax is an excellent
experiment in browsing and I'm excited seeing work has been done to
bring it to semweb use.

Regards,
Alan

On Mon, Jul 27, 2009 at 12:24 PM, Giovanni
Tummarello wrote:
> Dear Semi Structured Data Enthusiasts,
>
> we are today pleased to announce version 1 of Sparallax
>
> Sparallax is an adaptation of the  FreeBase Parallax to use SPARQL endpoints.
>
> Thanks to a proxy and query translation modules (SPARQL to MQL and
> results translated back), Sparallax is minimally invasive to the
> original code of Freebase Parallax and will be maintained in parallel
> in the same SVN repository.
>
> Due to requirements of query functionalities and aggregates, Sparallax
> currently only works on Virtuoso SPARQL endpoints. (do other
> triplestores have aggregates? if so please let us know and we'll try
> to support other syntaxes as well)
>
> Sparallax allows faceted browsing of very large and complex SPARQL
> datasets. More than this it allows moving from sets of resources to
> other sets which are related through properties
>
> Try sparallax on our test datasets or put just the URL of your SPARQL
> endpoint (but make sure you have materialized your RDFs triples, it's
> needed)
>
> http://sparallax.deri.ie/
>
> (please dont forget to visit the original parallax site, to watch that
> original screencast in case you didn't already)
>
> Big thanks to David Huynn for the support
> All credits must go to Nishant Jaint (Development) and Michele Catasta
> (Supervision)
>
> Giovanni
>
>

Re: owl:sameAs [recipe]

[Alan Ruttenberg]

On Mon, Jul 27, 2009 at 9:23 PM, Eric Lease
Morgan wrote:
>
> On Jul 25, 2009, at 5:09 AM, Bill Roberts wrote:
>
>> Regarding linking to external resources, what it seems you want
>> to do is to identify the dc:creator of the book, hence say that
>> the creator is the person whose name was Thomas More. You could
>> create your own URI and if you are managing a whole bunch of data
>> about books and authors, then there could be reasons to do that,
>> but in general if there is a satisfactory existing URI, it is
>> preferable to use it. Dbpedia seems to have become the de facto
>> standard...
>
>

I will put in, for the record, a dissenting voice to this recipe,
which I believe does not best serve the semantic web community.
Specifics below

> Okay, then how's this for a recipe to create rich linked data of electronic
> books and authors within my own site as well as to the outside world:
>
>  1. Mint URIs pointing to representations of local etexts

This one makes sense. There are particular manifestations (in the FRBR
sense) in the form of etexts, that you are providing.

>  2. Mint URIs pointing to representations of authors of local etexts

There is only one instance of an author. If there is an existing URI
for the author - a dbpedia URI, for instance, then I think that should
be used. There is no use for an additional URI, and having them puts
additional strain on every single client that has to manage them.

>  3. In resources of etexts, include owl:sameAs links to DBpedia resources

As I pointed out before, these are not sameAs. The dbpedia resource
are better understood as representing the expression, in the FRBR
sense, and the link from expression to manifestation is not sameAs.

>  4. In resources of etexts, point to local URIs of authors

No, point to already existing URIs of authors. If you have a web page
you wish to provide to give additional information about these
authors, link to that by an assertion
 foaf:page , or
 foaf:primaryTopicOf 

>  5. In resources of authors, include owl:sameAs links to DBpedia resources

It is not at all clear to me that you need or want additional RDF for
each author, unless you are saying something new about them. If it is
for indexing, then the links go both ways and an aggregator will be
able to follow the link you already established from etext to author.

>  6. In resources of authors, include owl:creatorOf links to local etexts

What is owl:creatorOf? I presume you would have used, in the
representation of the etext,
 dc:creator 

I am unconvinced, as I say above, that there is any need for you to
create any representation of the author.

>  7. For extra credit, do the same thing for subjects/keywords

Given the direction things are going, I am worried. This deserves
further explication.

> For example, the following resource descriptions:
>
> 
>   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#";
>  xmlns:dcterms="http://purl.org/dc/terms/";
>  xmlns:owl="http://www.w3.org/2002/07/owl#";
+  xmlns:frbr = "http://purl.org/vocab/frbr/core#";

>
>      rdf:about="http://infomotions.com/etexts/id/more-utopia-221";

-    owl:sameAs="http://dbpedia.org/resource/Utopia_(book)">
+   frbr:embodimentOf="http://dbpedia.org/resource/Utopia_(book)"
>
<

>    Utopia
>    http://infomotions.com/etexts/authors/resource/thomas-more"; />
+ rdf:resource="http://dbpedia.org/resource/Thomas_More"/>
>  

http://infomotions.com/authors/page/thomas-more";>
  http://dbpedia.org/resource/Thomas_More";>


> 


ditto for below

> 
>   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#";
>  xmlns:dcterms="http://purl.org/dc/terms/";
>  xmlns:owl="http://www.w3.org/2002/07/owl#";>
>      rdf:about="http://infomotions.com/etexts/id/more-reality-404";
>    owl:sameAs="http://dbpedia.org/resource/Reality_(book)">
>    Reality
>     rdf:resource="http://infomotions.com/etexts/authors/resource/thomas-more"; />
>  
> 
>
>

Toss this.

> 
>   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#";
>  xmlns:owl="http://www.w3.org/2002/07/owl#";>
>      rdf:about="http://infomotions.com/etexts/authors/resource/thomas-more";
>    owl:sameAs="http://dbpedia.org/resource/Thomas_More";>
>     rdf:resource="http://infomotions.com/etexts/id/more-utopia-221"/>
>     rdf:resource="http://infomotions.com/etexts/id/more-reality-404"; />
>  
> 
>
> --

Sorry to be critical, but there is an important principle here: First
do no harm. Willy nilly inventing URIs and entities when there are
perfectly good ones in existence is not "cool" from a semweb point of
view, and unnecessary use of sameAs is both burdensome and likely to
lead to gross errors, as I have pointed out in my previous emails.

-Alan

Re: owl:sameAs [recipe]

[Eric Lease Morgan]

On Jul 25, 2009, at 5:09 AM, Bill Roberts wrote:


Regarding linking to external resources, what it seems you want
to do is to identify the dc:creator of the book, hence say that
the creator is the person whose name was Thomas More. You could
create your own URI and if you are managing a whole bunch of data
about books and authors, then there could be reasons to do that,
but in general if there is a satisfactory existing URI, it is
preferable to use it. Dbpedia seems to have become the de facto
standard...



Okay, then how's this for a recipe to create rich linked data of  
electronic books and authors within my own site as well as to the  
outside world:


  1. Mint URIs pointing to representations of local etexts
  2. Mint URIs pointing to representations of authors of local etexts

  3. In resources of etexts, include owl:sameAs links to DBpedia  
resources

  4. In resources of etexts, point to local URIs of authors

  5. In resources of authors, include owl:sameAs links to DBpedia  
resources
  6. In resources of authors, include owl:creatorOf links to local  
etexts


  7. For extra credit, do the same thing for subjects/keywords

For example, the following resource descriptions:


http://www.w3.org/1999/02/22-rdf-syntax-ns#";
  xmlns:dcterms="http://purl.org/dc/terms/";
  xmlns:owl="http://www.w3.org/2002/07/owl#";>
  http://infomotions.com/etexts/id/more-utopia-221";
owl:sameAs="http://dbpedia.org/resource/Utopia_(book)">
Utopia
http://infomotions.com/etexts/authors/resource/thomas-more 
" />

  




http://www.w3.org/1999/02/22-rdf-syntax-ns#";
  xmlns:dcterms="http://purl.org/dc/terms/";
  xmlns:owl="http://www.w3.org/2002/07/owl#";>
  http://infomotions.com/etexts/id/more-reality-404";
owl:sameAs="http://dbpedia.org/resource/Reality_(book)">
Reality
http://infomotions.com/etexts/authors/resource/thomas-more 
" />

  




http://www.w3.org/1999/02/22-rdf-syntax-ns#";
  xmlns:owl="http://www.w3.org/2002/07/owl#";>
  rdf:about="http://infomotions.com/etexts/authors/resource/thomas-more 
"

owl:sameAs="http://dbpedia.org/resource/Thomas_More";>
http://infomotions.com/etexts/id/more-utopia-221 
"/>
http://infomotions.com/etexts/id/more-reality-404 
" />

  


--
Eric Lease Morgan

Re: ANN: Sparallax! - Browse sets of things together (now those on your SPARQL endpoint)

[Giovanni Tummarello]

Hi Kingsely,

we are a bit unsure about your complaint, please clarify,  do you mean
to say that sparallax give that user agent when trying to connect to
an external sparql endpoint?  we tried and got the user agent of the
browser. Not sure how it is important to use a user agent instead of
another when making a request to a sparql endpoint anyway.

In terms of what sparallax is for well i think a pretty interesting
use for Sparallax is that of installing it on the same servers as LOD
datasets and offereing it to the users as way to browse the entire
dataset via textual search and filtering/hopping from set to set.

This as opposed to (on top of) the simple click and browse currently
offered which does nothing but mimiking the normal document web. (its
completely impossible to explain to anyone what the power is).
With sparallax this becomes clear, you can search via text, then
browse, refine link etc.

if you have your sparql endpoint it all comes for free! :-) nothing
else to install but a simple .. Javascript (and a php file, ok)


Cheers!
Giovanni




> Giovanni,
>
> Please relay the following to whoever performed this port:
>
> Please unshackle the HTTP URIs of the "Things" mentioned in the page. Giving
> user agents "run scrip []" is simply not what the Web is supposed to be
> about.
>
> David fixed this glitch in his effort, so please embrace and extend his work
> with more Linked Data compliance, assuming this is a Linked Data oriented
> offering.
>
>
>
> --
>
>
> Regards,
>
> Kingsley Idehen       Weblog: http://www.openlinksw.com/blog/~kidehen
> President & CEO OpenLink Software     Web: http://www.openlinksw.com
>
>
>
>
>

Re: ANN: Sparallax! - Browse sets of things together (now those on your SPARQL endpoint)

[Kingsley Idehen]

Giovanni Tummarello wrote:

Dear Semi Structured Data Enthusiasts,

we are today pleased to announce version 1 of Sparallax

Sparallax is an adaptation of the  FreeBase Parallax to use SPARQL endpoints.

Thanks to a proxy and query translation modules (SPARQL to MQL and
results translated back), Sparallax is minimally invasive to the
original code of Freebase Parallax and will be maintained in parallel
in the same SVN repository.

Due to requirements of query functionalities and aggregates, Sparallax
currently only works on Virtuoso SPARQL endpoints. (do other
triplestores have aggregates? if so please let us know and we'll try
to support other syntaxes as well)

Sparallax allows faceted browsing of very large and complex SPARQL
datasets. More than this it allows moving from sets of resources to
other sets which are related through properties

Try sparallax on our test datasets or put just the URL of your SPARQL
endpoint (but make sure you have materialized your RDFs triples, it's
needed)

http://sparallax.deri.ie/

(please dont forget to visit the original parallax site, to watch that
original screencast in case you didn't already)

Big thanks to David Huynn for the support
All credits must go to Nishant Jaint (Development) and Michele Catasta
(Supervision)

Giovanni


  

Giovanni,

Please relay the following to whoever performed this port:

Please unshackle the HTTP URIs of the "Things" mentioned in the page. 
Giving user agents "run scrip []" is simply not what the Web is supposed 
to be about.


David fixed this glitch in his effort, so please embrace and extend his 
work with more Linked Data compliance, assuming this is a Linked Data 
oriented offering.




--


Regards,

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

ANN: Sparallax! - Browse sets of things together (now those on your SPARQL endpoint)

[Giovanni Tummarello]

Dear Semi Structured Data Enthusiasts,

we are today pleased to announce version 1 of Sparallax

Sparallax is an adaptation of the  FreeBase Parallax to use SPARQL endpoints.

Thanks to a proxy and query translation modules (SPARQL to MQL and
results translated back), Sparallax is minimally invasive to the
original code of Freebase Parallax and will be maintained in parallel
in the same SVN repository.

Due to requirements of query functionalities and aggregates, Sparallax
currently only works on Virtuoso SPARQL endpoints. (do other
triplestores have aggregates? if so please let us know and we'll try
to support other syntaxes as well)

Sparallax allows faceted browsing of very large and complex SPARQL
datasets. More than this it allows moving from sets of resources to
other sets which are related through properties

Try sparallax on our test datasets or put just the URL of your SPARQL
endpoint (but make sure you have materialized your RDFs triples, it's
needed)

http://sparallax.deri.ie/

(please dont forget to visit the original parallax site, to watch that
original screencast in case you didn't already)

Big thanks to David Huynn for the support
All credits must go to Nishant Jaint (Development) and Michele Catasta
(Supervision)

Giovanni

Re: Sig.ma - live views on the web of data

[Giovanni Tummarello]

Hi Leight

sorry for the delay

i think sigma likes this node in your ldodds-knows.rdf file way more
than it should
I have logged this as a bug or an improvement.
thanks
Giovanni




On Thu, Jul 23, 2009 at 4:19 PM, Leigh Dodds wrote:
> Hi,
>
> Nice service. I like how the descriptions are progressively enhanced.
>
> As is usual with a new search engine I instantly did a vanity search.
> Somehow it seems to have merged me with my children, wife and parents.
> I think the data is all correct, so perhaps some over-aggressive
> smushing in there somewhere?
>
> Cheers,
>
> L.
>
> 2009/7/23 Giovanni Tummarello :
>> Dear Web of Data enthusiasts,
>>
>> we are very happy to share with you today the first public version of
>> Sigma,  http://sig.ma ,  a browser, a mashup engine and an API for the
>> web of data.
>>
>> here is blog post with screencast, sample "sigma" embedded mashup etc.
>>
>> http://blog.sindice.com/2009/07/22/sigma-live-views-on-the-web-of-data/
>>
>> Sig.ma is heavily based on Sindice but also takes important hints from
>> Yahoo BOSS,  the OKKAM service and likely several others soon
>>
>> cheers
>>
>> Giovanni, also on behalf of all -  Michele Catasta, Richard Cyganiak
>> and Szymon Danielczyk who worked specifically on this but also
>> .. and of the Data Intensive Infrastructure Group, DERI as a whole.
>> http://di2.deri.ie/team/
>>
>>
>> __
>> This email has been scanned by the MessageLabs Email Security System.
>> For more information please visit http://www.messagelabs.com/email
>> __
>>
>
>
>
> --
> Leigh Dodds
> Programme Manager, Talis Platform
> Talis
> leigh.do...@talis.com
> http://www.talis.com
>

Re: Sig.ma - live views on the web of data

[Giovanni Tummarello]

Thanks Neubert,

sorry for the delay, was seriously taken for a few days.

Fine suggestions.

We'll add a host:* to what you can put in the box so that this can be
done very simply also some more url options to inject sources
explicitly, why not.

As a hacky workaround,  in the meanwhile a workaround can be to add a
specific term in the query e.g. if you ask
http://sig.ma/search?q=tim+berners+lee+dbpedia

you do tend to get more dbpedia sources than otherwise ;-) so if you
have a specific term in your datafiles (e.g. thename of your files) a
certain part of the queries would locate those first (or only).

Cheers
Giovanni

On Thu, Jul 23, 2009 at 9:05 AM, Neubert Joachim wrote:
> Hi guys,
>
> fine tool! Up to now I was a bit shy to demonstrate Semantic Web Browsers to 
> end users, and here I see the potential to don't have them scared away.
>
> The incremental enrichment of the view is very nice. However it would be 
> great to see our own sources showing up firsthand. Is there a possiblity to 
> influence the order in which sources are searched?
>
> One Suggestion: It would be great to have an option (maybe even as default 
> for new users) to show the labels instead or in front of the URIs, prefered 
> language according to browser settings. If a skos:prefLabel is available, 
> this one could be the best choice.
>
> Cheers, Joachim
>
>> -Ursprüngliche Nachricht-
>> Von: public-lod-requ...@w3.org
>> [mailto:public-lod-requ...@w3.org] Im Auftrag von Giovanni Tummarello
>> Gesendet: Donnerstag, 23. Juli 2009 02:58
>> An: semantic-web at W3C; Linking Open Data
>> Betreff: Sig.ma - live views on the web of data
>>
>> Dear Web of Data enthusiasts,
>>
>> we are very happy to share with you today the first public
>> version of Sigma,  http://sig.ma ,  a browser, a mashup
>> engine and an API for the web of data.
>>
>> here is blog post with screencast, sample "sigma" embedded mashup etc.
>>
>> http://blog.sindice.com/2009/07/22/sigma-live-views-on-the-web
>> -of-data/
>>
>> Sig.ma is heavily based on Sindice but also takes important
>> hints from Yahoo BOSS,  the OKKAM service and likely several
>> others soon
>>
>> cheers
>>
>> Giovanni, also on behalf of all -  Michele Catasta, Richard
>> Cyganiak and Szymon Danielczyk who worked specifically on
>> this but also .. and of the Data Intensive Infrastructure
>> Group, DERI as a whole.
>> http://di2.deri.ie/team/
>>
>>
>

RE: owl:sameAs

[bill.roberts]

Hi Eric
 
Regarding your first point - yes, your two options are equivalent and the 
second one is neater, so go for that.
 
Regarding linking to external resources, what it seems you want to do is to 
identify the dc:creator of the book, hence say that the creator is the person 
whose name was Thomas More.  You could create your own URI and if you are 
managing a whole bunch of data about books and authors, then there could be 
reasons to do that, but in general if there is a satisfactory existing URI, it 
is preferable to use it.  Dbpedia seems to have become the de facto standard so 
you could simply say:
 
http://www.w3.org/1999/02/22-rdf-syntax-ns 

 #"
   xmlns:dcterms="http://purl.org/dc/terms/ 
 
"
   xmlns:owl="http://www.w3.org/2002/07/owl 

 #">
   http://infomotions.com/etexts/id/more-utopia-221 

 
">
 http://dbpedia.org/resource/ 

 
Utopia_(book)" />
 http://dbpedia.org/resource/Thomas_More"; />
 people
 pleasure
   


If you want to go further and say that the person with that URI has name "More, 
Thomas" then you can add that as an additional triple with 
http://dbpedia.org/resource/Thomas_More as the subject, perhaps using the FOAF 
vocabulary.
 
Because owl:sameAs is used for saying that two URIs label the same thing, then 
you can't use it with literals. 
 
When it comes to the subjects, I expect that finding good, unambiguous URIs for 
concepts like 'people' or 'pleasure' is a bit more difficult. Perhaps other 
readers of the list might know about useful existing tagging/classification 
schemes you could use.  
 
I hope I'm understanding your problem correctly and hope these suggestions are 
helpful.
 
Regards
 
Bill Roberts



Van: public-lod-requ...@w3.org namens Eric Lease Morgan
Verzonden: ma 27-7-2009 15:54
Aan: public-lod@w3.org
Onderwerp: Re: owl:sameAs




On Jul 25, 2009, at 5:09 AM, Bill Roberts wrote:

>> I would like to make my Alex Catalogue more accessible as linked 
>> data, but I need some help in regards to the syntactical use of 
>> owl:sameAs.
>
> Simply use owl:sameAs like you would any other property.  The object 
> of the triple is the URI you want to say refers to the same thing.  So
>
>  http://infomotions.com/etexts/id/more-utopia-221
> >
> http://dbpedia.org/resource/Utopia_(book)">
>  


Thank you for the prompt reply, but I still need some additional help 
regarding syntax.

My goal is to link my resources as well as literals to outside 
resources. To link my books to additional versions of the books seems 
easy. Either of the following two example validate, but the later -- 
with an attribute -- seems simpler:

http://www.w3.org/1999/02/22-rdf-syntax-ns#";
   xmlns:dcterms="http://purl.org/dc/terms/";
   xmlns:owl="http://www.w3.org/2002/07/owl#";>

   http://infomotions.com/etexts/resource/more-utopia-221
">
 More, Thomas
 people
 pleasure
   

   http://infomotions.com/etexts/resource/more-utopia-221
">
 http://dbpedia.org/resource/
Utopia_(book)" />
   




http://www.w3.org/1999/02/22-rdf-syntax-ns#";
   xmlns:dcterms="http://purl.org/dc/terms/";
   xmlns:owl="http://www.w3.org/2002/07/owl#";>
   http://infomotions.com/etexts/id/more-utopia-221
">
 http://dbpedia.org/resource/
Utopia_(book)" />
 More, Thomas
 people
 pleasure
   



I suppose it is six of one and half a dozen of the other.

More importantly, how do link the creator and subject literals to 
outside resources? Adding owl:sameAs proves to invalidate the dcterms 
schema. Maybe I need to create local resources for each of my creators 
and subjects, and then link those to outside resources?

--
Eric Morgan

Re: owl:sameAs

[Eric Lease Morgan]

On Jul 25, 2009, at 5:09 AM, Bill Roberts wrote:

I would like to make my Alex Catalogue more accessible as linked  
data, but I need some help in regards to the syntactical use of  
owl:sameAs.


Simply use owl:sameAs like you would any other property.  The object  
of the triple is the URI you want to say refers to the same thing.  So


 http://infomotions.com/etexts/id/more-utopia-221 
>

http://dbpedia.org/resource/Utopia_(book)">
 



Thank you for the prompt reply, but I still need some additional help  
regarding syntax.


My goal is to link my resources as well as literals to outside  
resources. To link my books to additional versions of the books seems  
easy. Either of the following two example validate, but the later --  
with an attribute -- seems simpler:


http://www.w3.org/1999/02/22-rdf-syntax-ns#";
  xmlns:dcterms="http://purl.org/dc/terms/";
  xmlns:owl="http://www.w3.org/2002/07/owl#";>

  http://infomotions.com/etexts/resource/more-utopia-221 
">

More, Thomas
people
pleasure
  

  http://infomotions.com/etexts/resource/more-utopia-221 
">
http://dbpedia.org/resource/ 
Utopia_(book)" />

  




http://www.w3.org/1999/02/22-rdf-syntax-ns#";
  xmlns:dcterms="http://purl.org/dc/terms/";
  xmlns:owl="http://www.w3.org/2002/07/owl#";>
  http://infomotions.com/etexts/id/more-utopia-221 
">
http://dbpedia.org/resource/ 
Utopia_(book)" />

More, Thomas
people
pleasure
  



I suppose it is six of one and half a dozen of the other.

More importantly, how do link the creator and subject literals to  
outside resources? Adding owl:sameAs proves to invalidate the dcterms  
schema. Maybe I need to create local resources for each of my creators  
and subjects, and then link those to outside resources?


--
Eric Morgan

Re: cool urls and redirects

[Eric Lease Morgan]

On Jul 25, 2009, at 9:43 AM, Alan Ruttenberg wrote:

To what degree is it a best practice to implement "cool" URLs as  
redirects?


The essential thing is consistency. It is common practice to use
redirects from URIs that name resources. Often this is done so that it
will be possible, as is proposed in the Shared Name project, to move
hosting to a different server without having to notify people who have
made statements about the resource (or bookmarked them) and have them
adjust their content. In you case you are using a redirect from the
same domain, but you might consider using PURLs for you public facing
URLs.

If you do so, be consistent - make all RDF statements use the
preferred URLs, as well as all links in the HTML. For a dose of good
measure you might want to use rel=canonical in your html.


This sounds like sound advice. Thank you.

--
Eric Lease Morgan
Infomotions, Inc.

Re: owl:sameAs

[Hugh Glaser]

On 27/07/2009 11:50, "Ivan Herman"  wrote:

> Eric,
> 
> although not directly relevant to your question (ie, sorry to chime in
> on another subject) but you might want to consider using the bibo
> ontology for the books:
> 
> http://bibliontology.com/
> 
> this ontology is certainly getting attraction (tools like Zotero is
> planning to use it, for example). There are other ontologies for
> publications around, I guess bibo is probably the newest.
> 
> Just an idea...
> 
> Cheers
> 
> Ivan
And just to add to that.
We are truing to move towards bibo for the rkb stuff, and are using it for
our new dotAC project ( http://www.ecs.soton.ac.uk/research/projects/697 )
on UK research metadata.
Best
Hugh

Re: Alternatives to OWL for linked data?

[Ivan Herman]

Axel Rauschmayer wrote:
>> You were asking about description logic programming; well, OWL 2 RL:
>>
>> http://www.w3.org/TR/owl2-profiles/#OWL_2_RL
>>
>> is exactly that: it is a manifestation of DLP. It has a Direct Semantics
>> 'side', compatible with OWL 2 DL, and a rule based 'side', described by
>> the rule set:
>>
>> http://www.w3.org/TR/owl2-profiles/#Reasoning_in_OWL_2_RL_and_RDF_Graphs_using_Rules
>>
>>
>> This rule set can be used for a forward or backward chaining approach
>> (or a combination thereof) that you describe. I have heard rumours
>> and/or statements on implementations coming up from various vendors. I
>> have, actually, a purely proof-of-concept-stupid-simple implementation
>> doing brute force forward chaining:
>>
>> http://www.ivan-herman.net/Misc/2008/owlrl/
>>
>> Just to show what happens. And I am sure other implementations will come
>> to the fore that I do not yet about.
> 
> 
> Cool stuff. How would backward chaining work? Would it be invoked via
> SPARQL? Is listing all properties of a given resource still possible?
> 

At this moment, your guess is as good as mine:-) We will have to see how
implementers will come up with solution.

_Conceptually_ one could say that the SPARQL query is done on the
deductive closure (via OWL RL) of the data set. But taking it literally
(ie, expanding the graph with, say, forward chaining, and making the
query on top of it) is probably not efficient, so I expect implementers
coming up with cool tricks:-)

Ivan


> Axel
> 

-- 

Ivan Herman, W3C Semantic Web Activity Lead
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Re: Alternatives to OWL for linked data?

[Axel Rauschmayer]

You were asking about description logic programming; well, OWL 2 RL:

http://www.w3.org/TR/owl2-profiles/#OWL_2_RL

is exactly that: it is a manifestation of DLP. It has a Direct  
Semantics
'side', compatible with OWL 2 DL, and a rule based 'side', described  
by

the rule set:

http://www.w3.org/TR/owl2-profiles/#Reasoning_in_OWL_2_RL_and_RDF_Graphs_using_Rules

This rule set can be used for a forward or backward chaining approach
(or a combination thereof) that you describe. I have heard rumours
and/or statements on implementations coming up from various vendors. I
have, actually, a purely proof-of-concept-stupid-simple implementation
doing brute force forward chaining:

http://www.ivan-herman.net/Misc/2008/owlrl/

Just to show what happens. And I am sure other implementations will  
come

to the fore that I do not yet about.



Cool stuff. How would backward chaining work? Would it be invoked via  
SPARQL? Is listing all properties of a given resource still possible?


Axel

--
axel.rauschma...@ifi.lmu.de
http://www.pst.ifi.lmu.de/~rauschma/

Re: owl:sameAs

[Ivan Herman]

Eric,

although not directly relevant to your question (ie, sorry to chime in
on another subject) but you might want to consider using the bibo
ontology for the books:

http://bibliontology.com/

this ontology is certainly getting attraction (tools like Zotero is
planning to use it, for example). There are other ontologies for
publications around, I guess bibo is probably the newest.

Just an idea...

Cheers

Ivan

Eric Lease Morgan wrote:
> I would like to make my Alex Catalogue more accessible as linked data,
> but I need some help in regards to the syntactical use of owl:sameAs.
> 
> I am well on my way to minting URIs and "cool" URLs, I think. For example:
> 
>  * negotiation - http://infomotions.com/etexts/id/more-utopia-221
>  * RDF - http://infomotions.com/etexts/data/more-utopia-221
>  * HTML - http://infomotions.com/etexts/page/more-utopia-221
> 
> More importantly, I need to figure out how to make my RDF richer. Here
> is what I have so far for my local copy of Thomas More's Utopia:
> 
>  
>  xmlns:rdf = "http://www.w3.org/1999/02/22-rdf-syntax-ns#";
>xmlns:dcterms = "http://purl.org/dc/terms/";
>xmlns:owl = "http://www.w3.org/2002/07/owl# >
> 
> rdf:about="http://infomotions.com/etexts/id/more-utopia-221";>
>  More, Thomas
>  -00-00
>  
>  en
>  Wiretap Electronic Text Archive
> 
> http://creativecommons.org/licenses/GPL/2.0/
> 
>   rdf:resource="gopher://wiretap.spies.com:70/00/Library/Classic/utopia.txt";
> />
>  man
>  people
>  utopia
>  english
>  literature
>  Utopia
>  text
>   rdf:resource="http://infomotions.com/etexts/literature/english/1500-1599/more-utopia-221.txt";
> />
>   rdf:resource="http://infomotions.com/etexts/concordance/more-utopia-221"; />
>   rdf:resource="http://infomotions.com/etexts/page/more-utopia-221"; />
>
> 
>  
> 
> Specifically, I need to know how to:
> 
>  * specify that the title is the same as
> http://dbpedia.org/resource/Utopia_(book)
>  * specify the author is the same as
> http://dbpedia.org/resource/Thomas_More
>  * point the subject words to things like a linked data version of WordNet
> 
> Is most of this done by simply adding an owl:sameAs attribute to the
> appropriate element(s), like this:
> 
>rdf:about="http://infomotions.com/etexts/id/more-utopia-221";
>  owl:sameAs="http://dbpedia.org/resource/Utopia_(book)">
> 
> or
> 
>   owl:sameAs="http://dbpedia.org/resource/Thomas_More";>More,
> Thomas
> 

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Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
PGP Key: http://www.ivan-herman.net/pgpkey.html
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Re: Alternatives to OWL for linked data?

[Ivan Herman]

Axel,

you might want to have a look at the profiles of OWL 2:

http://www.w3.org/TR/owl2-profiles/

which tries to strike a balance. The idea for all these profiles is that
you trade in expressiveness for an ease of implementation. Ie, I would
not write off OWL just yet!

You were asking about description logic programming; well, OWL 2 RL:

http://www.w3.org/TR/owl2-profiles/#OWL_2_RL

is exactly that: it is a manifestation of DLP. It has a Direct Semantics
'side', compatible with OWL 2 DL, and a rule based 'side', described by
the rule set:

http://www.w3.org/TR/owl2-profiles/#Reasoning_in_OWL_2_RL_and_RDF_Graphs_using_Rules

This rule set can be used for a forward or backward chaining approach
(or a combination thereof) that you describe. I have heard rumours
and/or statements on implementations coming up from various vendors. I
have, actually, a purely proof-of-concept-stupid-simple implementation
doing brute force forward chaining:

http://www.ivan-herman.net/Misc/2008/owlrl/

Just to show what happens. And I am sure other implementations will come
to the fore that I do not yet about.

The other profile that might become interesting is OWL 2 QL:

http://www.w3.org/TR/owl2-profiles/#OWL_2_QL

that is, in many respect, simpler than RL and may be very advantageous
when mapped on top of SQL. Again, I have heard rumours of
implementations for that profile, too.

We can also expect that both these profiles (and others) will play well
with the new version of SPARQL (well, actually, with the current one,
too). Because OWL 2 RL provides a clear deductive closure via the rules,
that one is certainly not a problem; I am not 100% sure about QL (but I
am sure there will be ways).

Cheers

Ivan

P.S. B.t.w., OWL 2 RL is also 'expressed' via RIF rules

http://www.w3.org/2005/rules/wiki/OWLRL

in case you have looked at RIF before


Axel Rauschmayer wrote:
> I'm currently reading Hendler's brilliant book "Semantic Web for the
> Working Ontologist". It really drove home the point that OWL is not a
> good fit when using RDF for *data* (names are generally not unique, open
> world assumption, ...).
> 
> But what is the alternative? For my applications, I have the following
> requirements:
> 
> - Properties: transitivity, inverse, sub-properties.
> - Resources, classes: equivalence. For my purposes, equivalence is a way
> of implementing the topic merging in topic maps [1].
> - Constraints for integrity checking.
> - Schema declaration: partially overlaps with constraints, serves for
> documentation and for providing default values for properties.
> - Computed property values: for example, one property value being the
> concatenation of two other property values etc.
> 
> The difficulty seems to me to find something universal that fulfills
> these requirements and is still easy to understand. Inference, when used
> for transitivity and equivalence, is simple, but when it comes to
> editing RDF, they can confound the user: Why can some triples be
> replaced, others not? Why do I have to replace the triples of a
> different instance if I want to replace the triples in my instance?
> 
> While it's not necessarily easier to understand for end users, I've
> always found Prolog easy to understand, where OWL is more of a challenge.
> 
> So what solutions are out there? I would prefer description logic
> programming to OWL. Does Prolog-like backward-chaining make sense for
> RDF? If so, how would it be combined with SPARQL; or would it replace
> it? Or maybe something frame-based?
>
> Am I making sense? I would appreciate any pointers, hints and insights.
> 
> Axel
> 
> [1] http://www.topicmaps.org/xtm/index.html#desc-merging
> 

-- 

Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
PGP Key: http://www.ivan-herman.net/pgpkey.html
FOAF: http://www.ivan-herman.net/foaf.rdf


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