- From: Andreas Langegger <al@jku.at>
- Date: Tue, 17 Jun 2008 22:47:40 +0200
- To: Giovanni Tummarello <giovanni.tummarello@deri.org>
- Cc: Michael Hausenblas <michael.hausenblas@joanneum.at>, public-lod@w3.org, Semantic Web <semantic-web@w3.org>
Giovanni, On Jun 13, 2008, at 1:27 AM, Giovanni Tummarello wrote: > Licence: yes i agree, it will be added to the sitemap extention much > like it happens in microformats already. > if you want to use RDF i believe this is what you're looking for > http://validator.creativecommons.org/ yes, especially for LOD. In our case, we'll have to provide means of restriction and even billing (when SemWIQ gets integrated into Grid middleware - our requirement is a middleware for virtual data integration in the Grid). However, because I want SemWIQ being as generic as possible and also usable as a general data integration middleware, I want to re-use as much as possible and build on standards to be compatible to LOD/WOD. > Statistics: > > i'd tend to see this use case as a low level one that concerns > implementation of distributed sparql (an interesting aspect however!). sure. That's why I would extend voiD and maybe even Scuvo [1] for my purposes. > > It seems strange at least to ask people to write some triples to say > how many triples they have when a sparql endpoint is there just to > answer you any query you might want? that's why I said, it's just because of performance. At the moment my DataSourceMonitor uses a { [] a rdfs:Class } query to get classes of a dataset and then it iterates over classes to fetch instance statistics: count (*) where { [] a c_i } - this can be done remotely. However, for good cost-based optimization I need histograms for any class/property[/range] combination. RDFStats will run directly (and "nice") at a SPARQL endpoint to generate such histograms - at least in my case. Query federation for >20 public SPARQL endpoints is not feasible anyway with acceptable performance if you have many joins. > Sorry for the late answer, Andy [1] http://sw.joanneum.at/scovo/schema.html ---------------------------------------------------------------------- Dipl.-Ing.(FH) Andreas Langegger Institute for Applied Knowledge Processing Johannes Kepler University Linz A-4040 Linz, Altenberger Straße 69 http://www.langegger.at
Received on Tuesday, 17 June 2008 20:48:27 UTC