There are a few issue here that might need to be parsed out. The first is indexing Linked Data. It seems to make sense from a performance perspective to have a local index for the URIs and their names. For example

http://viaf.org/viaf/102333412             name: Austen, Jane

Pretend 'name' is an index field and the URI is the index key or ID. If you are using a Lucene index, you can imagine having multiple names based on language variation, preferred label variation (i.e. 'Austen, Jane, 1775-1817') etc.

Another issue has to do with what is cached in the index. I would argue that nothing other then the lookup values should be cached. The system should go off the the key/ID (i.e. the URI) and fetch the data from it. This is important because data can change all the time and you do not want to rely on having to download monthly data dumps to rebuild your index. Plus the idea of data dumps stands in opposition to the idea of Linked Data and the Web (i.e. its on the Web for a reason and that is to be accessed on the Web not downloaded and stored in a silo).

The third issue has to do with using VIAF URIs or coining your own local URIs. This is a bit of a toss up but I would argue that it would be better if you could coin your own URI and simply use a sameAs link to other entities, such as VIAF, LCSH, FAST etc. This would allow you to have a localized world-view of the entity. Or, to explain it better, it would allow you to put a localized lens on the entity and show things like how does this entity relate to other things that I have, know about, vend to patrons, etc.  There are also practice reasons for this. If I see a hot-link in my local Library OPAC for 'Jane Austen' I expect to stay within my local OPAC domain when I click on it. I do not want to be taken out to VIAF or another place. The reason for clicking it is to learn about it within the context of what I am doing on that website. Finally, coining your own URI allows you provide people with a bookmark-able URL. That is important for search engine visibility.

The last issue would require the index example above to not have a VIAF URI but rather a local URI that could be retrieved from a local Triple Store. In the store you could provide sameAs links to VIAF as well as localized information about the entity such as what he/she has authored that you current have available. 

Thanks,

Jeff Mixter
Research Support Specialist
OCLC Research
614-761-5159
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________________________________________
From: Code for Libraries <[log in to unmask]> on behalf of Esmé Cowles <[log in to unmask]>
Sent: Tuesday, February 24, 2015 3:09 PM
To: [log in to unmask]
Subject: Re: [CODE4LIB] linked data question

Yes, I would expect each organization to fetch linked data resources and maintain their own local indexes, and probably also cache the remote resources to make it easier and faster to work with them.  I've heard discussions of caching strategies, shared indexing tools, etc., but haven't heard about anyone distributing pre-indexed content.

Many vocabularies are available as RDF data dumps, which can sometimes be very large and unwieldy.  So I could imagine being able to download, e.g., a Solr index of the vocabulary instead of having to index it yourself.  But I haven't heard of anybody doing that.

-Esme

> On 02/24/15, at 10:56 AM, Harper, Cynthia <[log in to unmask]> wrote:
>
> Ann - I thought I'd refer part of your question to Code4lib.
>
> As far as having to click to get the linked data: systems that use linked data will be built to transit the link without the user being aware - it's the system that will follow that link and find the distributed data, then display it as it is programmed to do so.
>
> I think Code4libbers will know more about my question about distributed INDEXES?  This is my rudimentary knowledge of linked data - that the indexing process will have to transit the links, and build a local index to the data, even if in displaying the individual "records", it goes again out to the source.  But are there examples of distributed systems that have distributed INDEXES?  Or Am I wrong in envisioning an index as a separate entity from the data in today's technology?
>
> Cindy Harper
>
> -----Original Message-----
> From: Harper, Cynthia
> Sent: Tuesday, February 24, 2015 1:20 PM
> To: [log in to unmask]; 'Williams, Ann'
> Subject: RE: linked data question
>
> What I haven't read, but what I have wondered about, is whether so far, linked DATA is distributed, but the INDEXES are local?  Is there any example of a system with distributed INDEXES?
>
> Cindy Harper
> [log in to unmask]
>
> -----Original Message-----
> From: AUTOCAT [mailto:[log in to unmask]] On Behalf Of Williams, Ann
> Sent: Tuesday, February 24, 2015 10:26 AM
> To: [log in to unmask]
> Subject: [ACAT] linked data question
>
> I was just wondering how linked data will affect OPAC searching and discovery vs. a record with text approach. For example, we have various 856 links to publisher, summary and biographical information in our OPAC as well as ISBNs linking to ContentCafe. But none of that content is discoverable in the OPAC and it requires a further click on the part of patrons (many of whom won't click).
>
> Ann Williams
> USJ
> --
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