Kingsley,
Thanks for the background on how things are added manually when they hit your
radar,
for verifying that the default graph is the union, and
for the pointer to adding inference.
I’ll go have fun playing with the cache now :-)
Regards,
Tim
On Feb 20, 2014, at 3:02 PM, Kingsley Idehen <kide...@openlinksw.com> wrote:
> On 2/20/14 2:44 PM, Timothy Lebo wrote:
>> Virtuoso,
>>
>> I’m using the LOD Cloud Cache [1] as a sample of the LOD Cloud, and wanted
>> to make sure that I was using it to its full potential.
>> Thanks for such a useful resource.
>> Could you comment on the following?
>>
>>
>> A)
>> What portion of Linked Data is in the cache?
>
> You mean what portion of the datasets in the LOD Cloud pictorial are in this
> cache? If so, all the datasets we've been able to get our hands on over the
> years -- typically the larger ones.
>
>> i.e., what methodology is used to load data into the cache?
>
> We listen for new and interesting datasets an add them, basically.
>
>> Does it use crawls, load data dumps, use specific seed URIs or datasets?
>
> No, this is quite a manual process, at this time.
>
>> Do the lists at http://datahub.io/group/lodcloud or
>> http://datahub.io/dataset?tags=lod influence the loads?
>
> A little, but no more than a ping from someone, or a dataset announced via
> Twitter, G+, or LOD mailing list.
>
>>
>> Unfortunately, http://lod.openlinksw.com/facet_doc.html
>> mentionshttp://lod.openlinksw.com/void/Dataset, but that 404s.
>
> Yes, and for good reason, it has 50 Billion+ triples, and we've opted to fill
> the DBMS up with data rather than more data about datasets in the DBMS :-)
>
>>
>>
>> B)
>> How often is new Linked Data added to the cache?
>>
>
> As per my comments above, as an when a dataset comes to our attention.
>
>> C)
>> Is the default graph the only graph that one needs to query to “query all of
>> it”?
>
> Yes.
>
>> i.e., Can you verify http://lod.openlinksw.com/sparql's claim that:
>> <http://lod2.openlinksw.com/sparql> sd:feature
>> <http://www.w3.org/ns/sparql-service-description#UnionDefaultGraph>
>
> Yes query without a Named Graph IRI scope. Even better, search using a text
> pattern via <http://lod.openlinksw.com/fct> and then look at the "Metadata"
> tab which always shows you:
>
> 1. Named Graphs with triples where the description subject (i.e., entity
> denoted by the URI in About: section) is in the subject role
> 2. Ditto but where the description subject is in the object role
> 3. Explicit Coreferences
> 4. Inferred Coreferences.
>
>
>
>>
>> (and, what’s the difference between http://lod.openlinksw.com/sparql
>> andhttp://lod2.openlinksw.com/sparql?)
>
> No difference, just admin artifact re. DNS.
>
>>
>>
>> D)
>> Is the following query an appropriate way to find out how many foaf:Person
>> instances are in the cache?
>> I get 141,721,466 people.
>>
>> select count(?s) where {?s a <http://xmlns.com/foaf/0.1/Person>}
>
> Yes, but can also use "settings" to enable inference (there are some preset
> inference rules there plus the ability to enable owl:sameAs reasoning), which
> will increase the solution size.
>
>>
>>
>> E)
>> Is the following query an appropriate way to find out how many instances
>> foaf:knows another?
>> I get 84 “knowers”.
>>
>> select count(distinct ?s) where {?s <http://xmlns.com/foaf/0.1/knows> []}
>
> Yes, but note my comments about reasoning and inference.
>>
>>
>> Thanks so much for your time.
>>
>> Regards,
>> Tim
>>
>>
>> [1] http://lists.w3.org/Archives/Public/public-lod/2013May/0154.html
>> ------------------------------------------------------------------------------
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>
>
> --
>
> Regards,
>
> Kingsley Idehen
> Founder & CEO
> OpenLink Software
> Company Web: http://www.openlinksw.com
> Personal Weblog: http://www.openlinksw.com/blog/~kidehen
> Twitter Profile: https://twitter.com/kidehen
> Google+ Profile: https://plus.google.com/+KingsleyIdehen/about
> LinkedIn Profile: http://www.linkedin.com/in/kidehen
>
>
>
>
>
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