Re: RDF Update Feeds

FWIW, I had a quick look at the current caching support in LOD datasets [1]
- not very encouraging, to be honest.

Cheers,
      Michael

[1] http://webofdata.wordpress.com/2009/11/23/linked-open-data-http-caching/

-- 
Dr. Michael Hausenblas
LiDRC - Linked Data Research Centre
DERI - Digital Enterprise Research Institute
NUIG - National University of Ireland, Galway
Ireland, Europe
Tel. +353 91 495730
http://linkeddata.deri.ie/
http://sw-app.org/about.html

> From: Michael Hausenblas <michael.hausenblas@deri.org>
> Date: Sat, 21 Nov 2009 11:19:18 +0000
> To: Hugh Glaser <hg@ecs.soton.ac.uk>, Georgi Kobilarov
> <georgi.kobilarov@gmx.de>
> Cc: Linked Data community <public-lod@w3.org>
> Subject: Re: RDF Update Feeds
> Resent-From: Linked Data community <public-lod@w3.org>
> Resent-Date: Sat, 21 Nov 2009 11:19:57 +0000
> 
> Georgi, Hugh,
> 
>>> Could be very simple by expressing: "Pull our update-stream once per
>>> seconds/minute/hour in order to be *enough* up-to-date".
> 
> Ah, Georgi, I see. You seem to emphasise the quantitative side whereas I
> just seem to want to flag what kind of source it is. I agree that  "Pull our
> update-stream once per seconds/minute/hour in order to be *enough*
> up-to-date" should be available, however I think that having the information
> regular/irregular vs. how frequent the update should be made available as
> well. My main use case is motivated from the LOD application-writing area. I
> figured that I quite often have written code that essentially does the same:
> based on the type of data-source it either gets a live copy of the data or
> uses already local available data. Now, given that data set publisher would
> declare the characteristics of their dataset in terms of dynamics, one could
> write such a LOD cache quite easily, I guess, abstracting the necessary
> steps and hence offering a reusable solution. I'll follow-up on this one
> soon via a blog post with a concrete example.
> 
> My main question would be: what do we gain if we explicitly represent these
> characteristics, compared to what HTTP provides in terms of caching [1]. One
> might want to argue that the 'built-in' features are sort of too fine
> granular and there is a need for a data-source-level solution.
> 
>> in our semantic sitemaps, and these suggestions seem very similar.
>> Eg
>> http://dotac.rkbexplorer.com/sitemap.xml
>> (And I think these frequencies may correspond to "normal" sitemaps.)
>> So a naïve approach, if you want RDF, would be to use something very similar
>> (and simple).
>> Of course I am probably known for my naivity, which is often misplaced.
> 
> Hugh, of course you're right (as often ;). Technically, this sort of
> information ('changefreq') is available via sitemaps. Essentially, one could
> lift this to RDF straight-forward, if desired. If you look closely to what I
> propose, however, then you'll see that I aim at a sort of qualitative
> description which could drive my LOD cache (along with the other information
> I already have from the void:Dataset).
> 
> Now, before I continue to argue here on a purely theoretical level, lemme
> implement a demo and come back once I have something to discuss ;)
> 
> 
> Cheers,
>       Michael
> 
> [1] http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html
> 
> -- 
> Dr. Michael Hausenblas
> LiDRC - Linked Data Research Centre
> DERI - Digital Enterprise Research Institute
> NUIG - National University of Ireland, Galway
> Ireland, Europe
> Tel. +353 91 495730
> http://linkeddata.deri.ie/
> http://sw-app.org/about.html
> 
> 
> 
>> From: Hugh Glaser <hg@ecs.soton.ac.uk>
>> Date: Fri, 20 Nov 2009 18:29:17 +0000
>> To: Georgi Kobilarov <georgi.kobilarov@gmx.de>, Michael Hausenblas
>> <michael.hausenblas@deri.org>
>> Cc: Linked Data community <public-lod@w3.org>
>> Subject: Re: RDF Update Feeds
>> 
>> Sorry if I have missed something, but...
>> We currently put things like
>> <changefreq>monthly</changefreq>
>> <changefreq>daily</changefreq>
>> <changefreq>never</changefreq>
>> in our semantic sitemaps, and these suggestions seem very similar.
>> Eg
>> http://dotac.rkbexplorer.com/sitemap.xml
>> (And I think these frequencies may correspond to "normal" sitemaps.)
>> So a naïve approach, if you want RDF, would be to use something very similar
>> (and simple).
>> Of course I am probably known for my naivity, which is often misplaced.
>> Best
>> Hugh
>> 
>> On 20/11/2009 17:47, "Georgi Kobilarov" <georgi.kobilarov@gmx.de> wrote:
>> 
>>> Hi Michael,
>>> 
>>> nice write-up on the wiki! But I think the vocabulary you're proposing is
>>> too much generally descriptive. Dataset publishers, once offering update
>>> feeds, should not only tell that/if their datasets are "dynamic", but
>>> instead how dynamic they are.
>>> 
>>> Could be very simple by expressing: "Pull our update-stream once per
>>> seconds/minute/hour in order to be *enough* up-to-date".
>>> 
>>> Makes sense?
>>> 
>>> Cheers,
>>> Georgi 
>>> 
>>> --
>>> Georgi Kobilarov
>>> www.georgikobilarov.com
>>> 
>>>> -----Original Message-----
>>>> From: Michael Hausenblas [mailto:michael.hausenblas@deri.org]
>>>> Sent: Friday, November 20, 2009 4:01 PM
>>>> To: Georgi Kobilarov
>>>> Cc: Linked Data community
>>>> Subject: Re: RDF Update Feeds
>>>> 
>>>> 
>>>> Georgi, All,
>>>> 
>>>> I like the discussion, and as it seems to be a recurrent pattern as
>>>> pointed
>>>> out by Yves (which might be a sign that we need to invest some more
>>>> time
>>>> into it) I've tried to sum up a bit and started a straw-man proposal
>>>> for a
>>>> more coarse-grained solution [1].
>>>> 
>>>> Looking forward to hearing what you think ...
>>>> 
>>>> Cheers,
>>>>       Michael
>>>> 
>>>> [1] http://esw.w3.org/topic/DatasetDynamics
>>>> 
>>>> --
>>>> Dr. Michael Hausenblas
>>>> LiDRC - Linked Data Research Centre
>>>> DERI - Digital Enterprise Research Institute
>>>> NUIG - National University of Ireland, Galway
>>>> Ireland, Europe
>>>> Tel. +353 91 495730
>>>> http://linkeddata.deri.ie/
>>>> http://sw-app.org/about.html
>>>> 
>>>> 
>>>> 
>>>>> From: Georgi Kobilarov <georgi.kobilarov@gmx.de>
>>>>> Date: Tue, 17 Nov 2009 16:45:46 +0100
>>>>> To: Linked Data community <public-lod@w3.org>
>>>>> Subject: RDF Update Feeds
>>>>> Resent-From: Linked Data community <public-lod@w3.org>
>>>>> Resent-Date: Tue, 17 Nov 2009 15:46:30 +0000
>>>>> 
>>>>> Hi all,
>>>>> 
>>>>> I'd like to start a discussion about a topic that I think is getting
>>>>> increasingly important: RDF update feeds.
>>>>> 
>>>>> The linked data project is starting to move away from releases of
>>>> large data
>>>>> dumps towards incremental updates. But how can services consuming rdf
>>>> data
>>>>> from linked data sources get notified about changes? Is anyone aware
>>>> of
>>>>> activities to standardize such rdf update feeds, or at least aware of
>>>>> projects already providing any kind of update feed at all? And
>>>> related to
>>>>> that: How do we deal with RDF diffs?
>>>>> 
>>>>> Cheers,
>>>>> Georgi
>>>>> 
>>>>> --
>>>>> Georgi Kobilarov
>>>>> www.georgikobilarov.com
>>>>> 
>>>>> 
>>>>> 
>>> 
>>> 
>> 
> 
>

Received on Tuesday, 24 November 2009 08:52:05 UTC