Re: Available approaches for keyword based querying RDF federations

Thank you,Paul.


On Wed, Aug 13, 2014 at 8:19 PM, Paul Houle <ontology2@gmail.com> wrote:

> I would tend to stick up for a non-federated approach,  in the sense of
> gathering a lot of federated data into a centralized knowledge base and
> then querying that.  This is akin to how Google or Bing does web search by
> crawling the web and forming a distributed index.
>
> I can point to a number of reasons for this,  but some major ones are
>
> * many of the better IR algorithms depend on corpus-wide statistics,
>  topic modeling,  and other methods that need a global view (or at least a
> good sample of a global view)
> * even distributed search systems such as Solr (which in contrast to
> federated search are well controlled because the machines are in the same
> data center,  there is a deliberate approach to dealing with failures,
>  etc.) are not terribly scalable for the following reason.  If you run
> queries against N shards,  the time it takes to complete the query is
> greater than the the maximum response time.  As N gets bigger the
> probability that some glitch happens gets bigger and bigger.  Specifically
> when N>10 it is pretty hard to maintain an acceptable response time for
> interactive use.
>
> I'd say practically "centralized" search engines like Google and Bing have
> won the internet search war.  For various reasons, meta-search,  deep web
> search and similar services haven't really caught on.
>
>
>
> On Wed, Aug 13, 2014 at 8:12 AM, Thilini Cooray <
> thilinicooray.ucsc@gmail.com> wrote:
>
>> Hi,
>>
>> I would like to know available approaches for  keyword based querying RDF
>> federations.
>>
>> I found the following approach :
>> FedSearch: Efficiently Combining Structured Queries and Full-Text Search
>> in a SPARQL Federation by
>> Andriy Nikolov
>> <http://link.springer.com/search?facet-author=%22Andriy+Nikolov%22>,
>> Andreas Schwarte
>> <http://link.springer.com/search?facet-author=%22Andreas+Schwarte%22>,
>> Christian Hütter
>> <http://link.springer.com/search?facet-author=%22Christian+H%C3%BCtter%22>
>>
>> I would like to know whether there are any other approaches.
>>
>> Regards,
>> Thilini Cooray
>>
>
>
>
> --
> Paul Houle
> Expert on Freebase, DBpedia, Hadoop and RDF
> (607) 539 6254    paul.houle on Skype   ontology2@gmail.com
>