Re: Linked Data available

Richard,
Thank you very much for all your helpful suggestions.
We will look at them all, but it may take a little while to get round to
them.
I am sorry you have found it a rather frustrating experience.
In the meantime, here are some comments that might help.

On 7/11/07 21:46, "Richard Cyganiak" <richard@cyganiak.de> wrote:

> Hugh,
> 
> This looks like it could be an awesome resource. Unfortunately I
> didn't have much luck getting any kind of data back from the services.
> 
> The "browse" function doesn't do anything useful for me. I searched
> for a wide variety of terms, including "the", "a" and "2003" in the
> first ten or so datasets, including the one called Citeseer and DBLP.
> No results. What am I supposed to put into the search box?
I am not sure why you have found nothing at all.
Certainly I would not expect a response to such queries from things like
Citeseer, as the dataset to return would be enormous.
And even responses much smaller than this can take too long for the browser
to render, in addition.
I have tried "Hendler", "Fensel" and "Semantic Web" on the Citeseer data,
and seem to get sensible things.
> 
> I also tried to explore the datasets using SPARQL queries. I started
> with queries such as
> 
>     SELECT DISTINCT ?class WHERE { ?x a ?class }
> 
> to learn about the vocabulary used in the dataset. These queries
> return some results on some of the datasets (they time out on others),
> but clicking any of the results consistently showed a page with zero
> results. Same for opening in an RDF browser.
> 
> So in fact, despite honestly trying, the only way I could get any real
> data back from the services was by using the four example URIs
> provided at www.rkbexplorer.com .
> 
> Obviously a lot of work went into this. It's a shame that it's so hard
> to make any use of it because the last 5% are missing.
> 
> What are those last 5%?
> 
> 1. A brief description of what each dataset actually is, and what sort
> of data it contains. The currently available information (who provided
> the data and some triple counts) are not enough.
> 
> 2. A bunch of representative example URIs for each dataset.
(I did put a few at the bottom of the main page.)
> 
> 3. A bunch of representative and interesting SPARQL queries against
> each dataset.
Agreed for all three.
> 
> 4. If possible, a note on what vocabulary (classes and properties) are
> used in each dataset. This would greatly simplify SPARQLing the
> datasets.
OK.
In the meantime, the ontology is at
http://www.aktors.org/ontology/
And the Portal is probably the one you want.
So, for example
SELECT * WHERE { ?s <http://www.aktors.org/ontology/portal#has-author> ?o }
Will work fine on many of the datasets, such as newcastle
> 
> 5. You should think really hard about ³natural² navigation entry
> points into the datasets. Is there any natural ³root² from which
> everything can be accessed? Is there a category system or class
> hierarchy that one can navigate along to find interesting stuff?
I take the point, however (to explain a bit)...
We essentially have these datasets so that we can provide a way of providing
an ontology-mediated unified view of multiple, distributed, semantic web
repositories (a true semantic *web* application).
So we are putting our resources into this RKB Explorer.
The prototype was at http://resist.ecs.soton.ac.uk/explorer/
Having built that, however, the re-engineering so that we were not caching
the RDF locally anymore, and adhering to linked data standards, took much
longer than we would have liked.Since the datasets have been pretty much
ready for a while, it seemed a shame not to announce them (things are never
really ready).
I think it is hard to say what would be a useful "root" for things like NSF
or DBLP.
So our story for the navigation is twofold:
1) The data is public, and so it should be possible to use any reasonable
tool to explore (given the ontology);
2) We provide an application of our own (the RKB Explorer,
http://www.rkbexplorer.com/ ) which is a human interface.
I think this issue relates very neatly to the useability discussion: I see
the Semantic Web as essentially a universe of machines/agents communicating,
with humans being blissfully unaware that the interfaces they are using are
part of the Semantic Web.
This is our intention for RKB Explorer.
> 
> 6. You should consider adding a few domain-specific search functions,
> such as the simple ³Find Yourself² function provided at
> http://dblp.l3s.de/d2r/
I suspect that the Search facility in the RKB Explorer will be enough.
>   .
> 
> I'm a bit frustrated because this looks like an amazingly great
> resource, but I can't actually get any clear feeling for its scope or
> quality or contents. This feels like exploring a pitch black room
> while wearing boxing gloves.
I do take your point - sorry.
> 
> I'm very hopeful that you can greatly improve this experience with
> little effort.
> 
> Thanks a lot,
> Richard
> 
> 
> On 6 Nov 2007, at 16:00, Hugh Glaser wrote:
> 
>> 
>> Hi,
>> 
>> We have constructed some rdf resources and an application that uses
>> them,
>> that can be found at:
>> http://www.rkbexplorer.com/
>> 
>> Each resource has a different domain, to make it easy to use, and
>> emphasising the fact that these are in fact completely separate
>> knowledge
>> bases.
>> 
>> For each resource, you can access it in the following ways:
>> 
>> Browse it, looking at the RDF triples;
>> Query it, using SPARQL;
>> Resolve each of the unique URIs for resources: depending on content
>> negotiation, RDF or HTML will be returned;
>> Query the associated CRS (Consistent Reference Service), to find out
>> which
>> other URIs are considered to be the same non-information resource.
>> 
>> We currently have the following:
>> 
>> budapest.rkbexplorer.com
>> citeseer.rkbexplorer.com
>> cordis.rkbexplorer.com
>> darmstadt.rkbexplorer.com
>> dblp.rkbexplorer.com
>> deepblue.rkbexplorer.com
>> eurecom.rkbexplorer.com
>> ft.rkbexplorer.com
>> ibm.rkbexplorer.com
>> ieee.rkbexplorer.com
>> irit.rkbexplorer.com
>> italy.rkbexplorer.com
>> kaunas.rkbexplorer.com
>> laas.rkbexplorer.com
>> lisbon.rkbexplorer.com
>> newcastle.rkbexplorer.com
>> nsf.rkbexplorer.com
>> pisa.rkbexplorer.com
>> roma.rkbexplorer.com
>> southampton.rkbexplorer.com
>> ulm.rkbexplorer.com
>> wiki.rkbexplorer.com
>> 
>> There are some quite big resources here: citeseer, cordis, dblp and
>> nsf are
>> a good size.
>> 
>> They all use the same ontology (AKT Reference Ontology, with some
>> small
>> additions), which hopefully makes them a useful resource for
>> applications
>> that use ontology-mediated separate knowledge bases.
>> 
>> There is also such an application:
>> http://www.rkbexplorer.com/explorer/
>> Since we have rebuilt the knowledge bases to conform to linked data
>> standards, the search and CRS information is still being analysed,
>> and thus
>> this version of the RKB explorer does not yet present as unified a
>> view as
>> we would like.
>> For a better unified view, please see the old version at
>> http://resist.ecs.soton.ac.uk/explorer/
>> 
>> Best
>> Hugh
>> 
>> -- 
>> Hugh Glaser,  Reader
>>               Dependable Systems & Software Engineering
>>               School of Electronics and Computer Science,
>>               University of Southampton,
>>               Southampton SO17 1BJ
>> Work: +44 (0)23 8059 3670, Fax: +44 (0)23 8059 3045
>> Mobile: +44 (0)78 9422 3822, Home: +44 (0)23 8061 5652
>> http://www.ecs.soton.ac.uk/~hg/
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>

Received on Wednesday, 7 November 2007 23:08:54 UTC