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Re: Owning URIs (Was: Yet Another LOD cloud browser)

From: Samur Araujo <samuraraujo@gmail.com>
Date: Tue, 2 Jun 2009 12:34:34 -0300
Message-ID: <4bb9c0570906020834v24a4eaa2qaeb0430a0140aa71@mail.gmail.com>
To: Sherman Monroe <sdmonroe@gmail.com>
Cc: Daniel Schwabe <dschwabe@inf.puc-rio.br>, Kingsley Idehen <kidehen@openlinksw.com>, Linked Data community <public-lod@w3.org>, semantic-web@w3.org
Dear Sherman, note that no matter what query tool or browser you are using,
it is necessary to tune the underline database to achieve your performance
requirements. Enabling all Explorator's repositories mean that you want to
query several databases and sparql enpoint at the same time. When you do so,
Explorator queries a federation of endpoints, groups all results and
retrieves an  unique set of triples. Of course, you should keep in mind that
we have not tune our sesame or virtuoso instances to achieve the best
performance, also we have not created FTS for sesame or virtuoso yet.
Again, such performance problem will be encountered no matter what system
you use.

About sesame, we are using it just as a proof of concept, however you can
extend Explorator adapters to connect to others rdf repositories. At the
moment, Explorator is able to connect to whatever sparql endpoint (we have
tested it for Virtuoso and Sesame endpoints.) you want. Keep in mind that we
can not guarantee performance for external endpoints. Most of them retrieve
timeout when you do a complex query that takes longer that a few


Samur Araujo

On Tue, Jun 2, 2009 at 11:45 AM, Samur Araujo <samuraraujo@gmail.com> wrote:

> Dear Sherman, Notes that doesn
> On Tue, Jun 2, 2009 at 11:43 AM, Sherman Monroe <sdmonroe@gmail.com>wrote:
>> Daniel,
>> I see some interesting concepts worth exploring here, e.g. using windows
>> (with paging inside the window). But as I refine my query, there isn't any
>> apparent context that orients me in the data. E.g. how does one box/set
>> relate to the others.
>> I notice you're using Sesame, do you think it can scale? I tried selecting
>> several repositories at once, but the system seems to hang awhile (couple of
>> minutes)  before returning results.
>> -sherman
>> On Tue, Jun 2, 2009 at 8:26 AM, Daniel Schwabe <dschwabe@inf.puc-rio.br>wrote:
>>> Kingsley Idehen wrote:
>>>> Daniel Schwabe wrote:
>>>>> Sherman,
>>>>> as another alternative, I urge you to take a look at Explorator [1]
>>>>> (there is a short movie explaining the basic idea, you can also play with
>>>>> the live interface), which can do all of what you said, and more.
>>>>> It provides a more general exploration paradigm, of which the example
>>>>> you give below is only one of the possibilities...
>>>>> Best
>>>>> Daniel
>>>>> [1] http://www.tecweb.inf.puc-rio.br/explorator.
>>>> Daniel,
>>>> When you speak to the <http://lod.openlinksw.com> instance, do you use
>>>> SPARQL Protocol or the Faceted Browsing REST API or either depending on task
>>>> ?
>>>> I suspect SPARQL protocol,  but please confirm.
>>>>  We use the SPARQL protocol, because the code is geared to deal with any
>>> SPARQL endpoint. The only thing we have customize, precisely because of lack
>>> of standardization, is the FTS function. There is special code to detect
>>> when the server is Virtuoso, to use bif:contains. Other than that, is uses
>>> standard constructs.
>>> If I understand it correctly, the Faceted Browsing REST API would not
>>> allow us to issue the kinds of queries we need; as I mentioned in earlier
>>> messages, Explorator is much more than pure faceted browsing.
>>> Did you have anything specific in mind in this regard?
>>> Cheers
>>> D.
>> --
>> Thanks,
>> -sherman
>> I pray that you may prosper in all things and be healthy, even as your
>> soul prospers
>> (3 John 1:2)
Received on Tuesday, 2 June 2009 15:40:06 UTC

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