Re: AW: [smila-dev] Re: [Aperture-devel] Aperture bundlization for SMILA

[Leo Sauermann <leo.sauermann@xxxxxxx>]

It was Daniel.Stucky@xxxxxxxxxxx who said at the right time 26.01.2009 15:17 the following words:

Hi all,
some more comments inline. (It's getting confusing :-) )
  

I cut down the length..... I am looking at the other mail by Antoni *right now*
he has some points ... will answer later... one thing about RDF now:

aperture is a SEMANTIC framework (as the S in SMILA :-),
so we build on RDF,
= sesame has to stay in or nothing will work in aperture.

theoretically, it can be exchanged by Jena, because we are based on
RDF2go,
but you don't want to look into their own private hell of ~10mb of
dependencies
    

I know that aperture is based on RDF, I hoped that for just using extractors no RDF store was required. I still think it is not used anyway, but some implementations just come with this jar. 
On the other hand this offers Smila a ready to use rdfstore, which will be needed in the near future. This is nice.
  

Ha, truth is:
we use the Sesame implementation's in-memory RDF containers!
(called memoryrepository).

We use these containers everywhere!
also in the extractors.
see also:
http://aperture.wiki.sourceforge.net/RDFUsage

We use the in-memory models as a kind of "complex hashmap that does all the RDF tricks including sparql", which is the way to go, which is clever, and "good".
To pass around RDF from one place in the framework to another, this in-memory representation is perfect.
Also we need Sesame to actually create the data - we use RDF2go and sesame
inside the extractors and crawlers to express the information.

Aperture as such does *not* use the disk-backed storage model of sesame,
although projects built on aperture may do.

For SMILA we will have the same problem:
how to hande  in-memory RDF.
You need parsers, serilaizers, inferencers,
sparql, programming API, in-memory model, etc etc etc
I know about this, but I have no time to spent in SMILA to manage a working group to do it,
so best would be if someone picks up the ball there,
the best solution would be to just copy the Aperture model (rdf2go and sesame) for now,
and then use it for a while until SMILA has gathered enough experience with RDF
to bake its own.

Just for the records:
we thought about making a JSR for RDF2Go long ago,
Henry Story from SUN just loved the idea.
but confronted with the overwhelming work that THIS would take
(= multiple manyears) we quickly gave up on this idea.
of course, sooner or later a JSR for handling RDF in memory
and a JSR for RDF storage abstaction will hopefully evolve,
and if you weigh me in gold to pay for these man-years I would even
be eager to work in such a standardization group ;-)

best
Leo

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DI Leo Sauermann       http://www.dfki.de/~sauermann 

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