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Re: fast inferencing with jena and "?"

From: Dave Reynolds <der@hplb.hpl.hp.com>
Date: Tue, 22 Mar 2005 17:32:52 +0000
Message-ID: <424056C4.70900@hplb.hpl.hp.com>
To: Leo Sauermann <leo@gnowsis.com>
CC: semantic-web@w3.org

Hi Leo,

OK. I understand about commercial sensitivity, though an abstracted data 
example might still be possible.

There are a few coding approaches that could make a difference to 
performance of that sort of algorithm. Rather than spam this list with 
jena-specific details I'll take the rest of the discussion off list (and 
copy to jena-dev).

Cheers,
Dave

Leo Sauermann wrote:

> Hi Dave,
> 
> actually a colleague of me is doing it and it is a commercial project we 
> do for a telecommunications company, so we can't publish the triples :-|
> 
> roughly, its about checking if two graph A, B are "near" to each other,
> A,B describe resources and the resources are of Schema S
> now what we do is complete A and B by using S and then doing some graph 
> matching algorithm combined with property matching,
> so we combine A with S and B with S and then use A(S) and B(S) to do the 
> matching.
> 
> like
> if type(A(S)) == type(B(S)) then "quite match"
> and forallPropertiesOf( prop(A(S)) == prop(B(S))) then add "quite match"
> ...
> 
> so there are  a few find(spo) that fire into the graph which the graph 
> does not like
> 
> we'll try the new Jena release and see what happens.
> 
> regards
> Leo
> 
> Es begab sich aber zu der Zeit 21.03.2005 12:16,  da Dave Reynolds schrieb:
> 
>>
>> Hi Leo,
>>
>>> The problem with Jena is: the Model RDFS_MEM_TRANS_INF is too slow to do
>>> simple inference (and it was the fastest we found in jena)
>>
>>
>>
>> Which version of Jena? There was a bug fix affecting TRANS between 2.1 
>> and 2.2beta1 and a performance problem fixed between 2.2beta1 and 
>> 2.2beta2.
>>
>>> It has 200ms performance of matching two small rdf instance models
>>> against a RDF/S ontology model (180 classes). 
>>
>>
>>
>> What do you mean by "matching" a model against an RDFS model?
>>
>> If you can show us what you are doing (ideally a self-contained code 
>> example) then we might be able to advise on optimizations. Though code 
>> exchange is probably better done over on jena-dev or off list.
>>
>>> We did everything we could to make it faster, including prefetching all
>>> classes, properties, trying out different Jena inferencers, etc.
>>
>>
>>
>> If you prefetched all classes and properties then there is presumably 
>> no inference left. If the performance wasn't good enough in that set 
>> up then you don't need faster inference you need a faster algorithm or 
>> reduced API overheads. That would make it even more interesting to see 
>> exactly what you are doing to figure where the performance problem is.
>>
>> Cheers,
>> Dave
>>
>>
> 
Received on Tuesday, 22 March 2005 17:33:25 UTC

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