Actually, we have developed experience on this issue (SPARQL-based
implementation for path extraction). I think that Andrea could lead
the task and bring in the work already done as a starting point.
We have also identified a number of indicators that is worth to
compute and associate to paths. Everything is in the two papers (and
the vocabulary) referred by Andrea. For example, we compute the
occurrences of paths in a dataset, their popularity (we have defined a
measure for this), and other ones.
They can be optional features offered by the SPARQL-based services.
Val
Quoting [email protected]:
Hi Rupert, Stanbol team
I am interested in the SPARQL based implementation.
We have recently worked on extracting paths from linked data.
The work has been just presented at ISWC [1, 2].
Hence I have already some experience with the issue and some preliminary
results to reuse:
* a number of scripts for extracting paths
* a vocabulary for representing and storing them [3]
I am not sure I will be in Salzburg, but we can discuss this possibility
for including these issues at the hackathon.
--
Andrea Giovanni Nuzzolese
Semantic Technology Laboratory (STLab)
Institute for Cognitive Science and Technology (ISTC)
National Research Council (CNR)
Via Nomentana 56, Roma - Italy
[1] http://www.stlab.istc.cnr.it/documents/papers/cold2011.pdf
[2] http://www.stlab.istc.cnr.it/documents/papers/wikilinkpatterns.pdf
[3] http://www.ontologydesignpatterns.org/ont/lod-analysis-properties.owl
Hi Sebastian, Jakob, Stanbol team
Based on the positive feedback of Anil to participate on this I decided to
create an own thread to plan the next steps.
Next steps:
The first step will be to define Java API that allows to provide different
implementations. I think the Idea was to create an own Project (should we
use Github or GoogleCode? MIT/BSD/Apache licensed?) that only focusses on
the Specification of the Language [1] and the Java API. Sebastian needs to
take the lead of this. If I remember correctly his plan was to start this
next week.
As soon as a first version of this specification is available we can start
to work on implementations.
* Kiwi TripleStore: I assume Sebastian and Jakob will work on that
* Clerezza: Anil could you take the lead for that?
* Entityhub: This will be my responsibility
* SPARQL based implementation: I think that would be interesting - someone
interested to work on that?
* CMS Adapter: Suat could you follow this effort and check for possible
usage scenarios.
* Fact Store: This could be also an interesting. But same as for the CMS
Adapter we need first to check usage scenarios.
best
Rupert
On 28.10.2011, at 10:07, Ali Anil SINACI wrote:
Dear Rupert,
On 10/28/2011 08:47 AM, Rupert Westenthaler wrote:
On 27.10.2011, at 16:59, Ali Anil SINACI wrote:
* The LMF semantic search component overlaps greatly with the
recently by Anil contributed "contenthub/search/engines/solr"
component. Related to this it would be great if Anil could have a
look at [2] and check for similarities/differencies and possible
integration paths.
I had a look on the semantic search component of LMF. As you pointed
it out, LMF semantic search provides a convenient way to index any
part of documents with the help of RDFPath Language. I think that we
can make use of this feature in contenthub. As I described in my
previous e-mail, currently, contenthub indexes a number of semantic
fields based on DBPedia relations. These are hardcoded relations.
RDFPath language can be used to indicate specific semantic fields to
be indexed along with the content itself. Let me describe the thing in
our mind in a scenario:
A user provides a domain ontology (e.g. music domain), submits to
Entityhub to be used in the enhancement process. Suppose the domain
ontology includes vast of information about artists, their albums
etc... I assume that this ontology does not include conceptual
definitions (it only includes Abox definitions). User writes an RDF
Path Program (in LMF terminology) to indicate the fields to be indexed
when a content item has an enhancement related with any path in that
program. Suppose user submits a content item along with the RDF Path
Program(s) to be used to determine the fields to be indexed.
Enhancement engines find an entity (or lots of entities). Now, we
execute the selected RDF Path Program(s) and embed the results into
the Solr representation of the content item.
If you have any other suggestions, please let me know so that we can
discuss in detail (in SRDC) before the meeting.
This is exactly what I was thinking about. Let me only add that such
additional Knowledge to be included within the Semantic Index might not
only come from the Entityhub, but also from other sources (like the CMS
via the CMS adapter)
I you would like to help me with an Implementation of the
RdfPathLanguage (e.g. the Clerezza based Implementation, or maybe a
Jena bases implementation) please let me know. Help would be greatly
welcome, because I have already a lot of things on my TODO list before
the Meeting in November (such as defining a Proposal for the Stanbol
Enhancement Structure).
We would like to get involved in the implementation of RDFPathLanguage
for Stanbol. We plan to work on this starting from next week. I think
you & LMF team already have a design in your mind. I will appreciate if
you could share your thoughts with us.
* The Semantic Search Inteface: The Contenthub currently defines it's
own query API (supports keyword based search as well as "field ->
value" like constraints, supports facets). The LMF directly exposes
the RESTful API of the semantic Solr index. I strongly prefer the
approach of the LMF, because the two points already described above.
We think that we do not have to make a selection here. We can keep a
simple wrap-up on the Solr interface (contenthub's own query API)
while providing the Solr RESTful API as is. IMO a wrap-up on Solr
interface would be beneficial. On the other hand, in this interface we
try to make use of an ontology to be used in
OntologyResourceSearchEngine. This might help to figure out new
keywords based on the subsumption hierarchy inside the ontology.
However, I think this may lead to performance issues and may not be
useful at all. We can decide on this later.
You forgot to mention one additional advantage for using the Solr
RESTful API: If we do that one could create the Semantic Index and than
copy it over to some other SolrServer without the need to run Stanbol
directly on the production infrastructure.
In general I would suggest to first focus the discussion on the unique
features we would like to provide with the Semantic Search component. I
already included three features I would like to have in my first Mail
(Query preprocessing, Entity Facets, Semantic Facets). As you now
mention the OntologyResourceSearchEngine is very relevant in relation
to such features.
However adding such features must not necessarily mean to create an own
query language. One could also try to add such features directly to
Solr by implementing some Solr extensions.
Let me briefly comment in your suggestions about the semantic search.
But I am also the opinion that a semantic search interface should at
least provide the following three additional features:
1. Query preprocessing: e.g. substitute "Paris" in the query
with "http://dbpedia.org/resource/Paris";;
2. Entity Facets: if a keyword matches a Entity (e.g. "Paris" ->
"dbpedia:Paris", "dbpedia:Paris_Texas", "dbpedia:Paris_Hilton")
than provide a Facet to the user over such possible
nnnnnnnnmatches;
As far as we understand, first and second features will be handled by
querying the Entityhub with the query keyword (Paris) i.e the first
entity obtained from the Entityhub will help us to recognize its type
and the other entities will be served as facet values of Paris facet.
3. Semantic Facets: if a user uses an instance of an ontology
type (e.g. a Place, Person, Organization) in a query, that
provide facets over semantic relations for such types (e.g.
fiends for persons, products/services for Organizations, nearby
Points-Of-Interests for Places, Participants for Events,
). To
implement features like that we need components that provide
query preprocessing capabilities based on data available in the
Entityhub, Ontonet
. To me it seams that the
contenthub/search/engines/ontologyresource component provides
already some functionality related to this so this might be a
good starting point.
Currently, we are trying to integrate an exploration mechanism like you
said above. It is also based on DBPedia ontology.
OntologyResourceEngine can be used for this purpose for the user
registered ontologies. Current implementation of this engine only
computes closures by exploiting the hierarchy in the ontology. RDFPath
Programs can also be an option at this point. With an RDF Path Program
user may specify the relations to be used in the exploration process.
But I think this means the user decides beforehand which fields should
be presented to him as exploration fields. I think this is open to
discussion.
best
Rupert
Regards,
Anil.
----------------------------------------------------------------
This message was sent using IMP, the Internet Messaging Program.
