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Re: The Power of Virtuoso Sponger Technology

From: Kingsley Idehen <kidehen@openlinksw.com>
Date: Sun, 18 Oct 2009 14:03:27 -0400
Message-ID: <4ADB586F.1070406@openlinksw.com>
To: Olaf Hartig <hartig@informatik.hu-berlin.de>
CC: "public-lod@w3.org" <public-lod@w3.org>
Olaf Hartig wrote:
> Hey,
>
> On Sunday 18 October 2009 09:37:14 Martin Hepp (UniBW) wrote:
>   
>> [...]
>> So it will boil down to technology that combines (1) crawling and
>> caching rather stable data sets with (2) distributing queries and parts
>> of queries among the right SPARQL endpoints (whatever actual DB
>> technology they expose).
>>
>> You can keep a text index of the whole Web, if crawling cycles in the
>> order of magnitude of weeks are fine. For structured, linked data that
>> exposes dynamic database content, "dumb" crawling and caching will not
>> scale.
>>     
>
> Interesting discussion!
>
> An alternative approach to query federation is the link traversal based query 
> execution as implemented in the SemWeb Client Lib. The main idea of this 
> approach is to look-up URIs during the query execution itself. With this 
> approach you don't rely on the existence of SPARQL endpoints and -even more 
> important- you don't have to know all the sources that contribute to the query 
> result in advance. Plus, the results are based on the most up-to-date data you 
> can get.
>
> Greetings,
> Olaf
>
>
>
>   
Olaf,

SemWeb Client [1] should benefit immensely from Sponger URIs.

If the SemWeb Client enables its consuming programs to designate 
traversal predicates beyond "seeAlso", even better. I say this because 
of the following statement from you "how it works" section: "..look up 
any URI y where the graph set includes the triple { x rdfs:seeAlso y } 
and x is a URI from the triple pattern. Add retrieved graphs to the 
local graph set."

Once you add custom crawl property/predicate designation, the SemWeb 
Client library is basically similar to what the Sponger does inside the 
Virtuoso Engine [2][3]:-)

Links:

1. http://www4.wiwiss.fu-berlin.de/bizer/ng4j/semwebclient/
2. http://virtuoso.openlinksw.com/dataspace/dav/wiki/Main/VirtSponger
3. http://docs.openlinksw.com/virtuoso/rdfiridereferencing.html
4. 
http://virtuoso.openlinksw.com/Whitepapers/html/VirtSpongerWhitePaper.html

-- 


Regards,

Kingsley Idehen	      Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO 
OpenLink Software     Web: http://www.openlinksw.com
Received on Sunday, 18 October 2009 18:03:58 UTC

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