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Re: Linked Data Fragments: Web-scale querying

From: (wrong string) čius <martynas@graphity.org>
Date: Wed, 19 Mar 2014 12:58:15 +0100
Message-ID: <CAE35VmxEHDLRAxpjoDtLOGs4hHcFdv59GWDdtYj8qGkj3FOBzA@mail.gmail.com>
To: Luca Matteis <lmatteis@gmail.com>
Cc: Kingsley Idehen <kidehen@openlinksw.com>, Linked Data community <public-lod@w3.org>, "semantic-web@w3.org Web" <semantic-web@w3.org>

interesting stuff. I remember another project that does something like that:
SQUIN http://squin.sourceforge.net/index.shtml

How does LDF compare to to it?



On Wed, Mar 19, 2014 at 12:41 PM, Luca Matteis <lmatteis@gmail.com> wrote:
> Hi Rueben,
> Just finished reading the paper. Really great stuff. The idea of
> splitting a single resourceful SPARQL request into multiple
> fine-grained requests was always attractive to me and I've also
> thought of something similar (http://lmatteis.github.io/restpark/). I
> applaud you and your team for coming up with a formal client algorithm
> as well as a server implementation for offering this functionality.
> I wonder, given a Linked Data set, if you could easily and generically
> wrap it with a basic LDF interface. Sort of how Pubby wraps SPARQL to
> expose Linked Data, maybe there can be a wrapper for a Linked Data
> site to expose basic LDF.
> This makes sense because:
> * I build a nice site and my data is available as HTML, marked up with RDFa
> * Database is not a triple store, just regular MySQL
> If people want to query this data, they have to crawl all my RDFa
> pages and stuck them in their own triple-store.
> Where I see LDF being a *huge* deal is that I could use something to
> wrap my RDFa pages and expose a basic LDF server, without having to
> change any of my technology stack for my app. This could potentially
> allow thousands of RDFa providers to expose querying functionality
> with minimum effort.
> Best,
> Luca
> On Tue, Mar 11, 2014 at 8:27 PM, Kingsley Idehen <kidehen@openlinksw.com> wrote:
>> On 3/11/14 12:36 PM, Bernadette Hyland wrote:
>> Dear Semantic Web and Linked Data enthusiasts,
>> If you're curious about new ways to query Linked Data,
>> you might like our Linked Data Fragments client.
>> It lets your browser execute SPARQL queries over Web data
>> in a scalable way: http://client.linkeddatafragments.org/
>> Today's answer to Web querying consists of SPARQL endpoints.
>> Publishers of data sets offer a public endpoint, which
>> answers highly specific questions for any client. Unfortunately,
>> the availability of public SPARQL endpoints is problematic [1] -
>> and thus so is the availability of publicly queryable datasets.
>> We cannot rely on them for building applications, and that's a pity.
>> It is not an issue of performance but an inherent architectural issue:
>> making a public server responsible for arbitrarily complex requests
>> doesn't work on a Web scale. We have to create more simple servers,
>> only answering simple questions that don't endanger availability.
>> Yet at the same time, the dataset should remain easily queryable.
>> This is the goal of the Linked Data Fragments project [2].
>> "Linked Data Fragments" is a term for all ways to offer parts of a dataset:
>> - SPARQL results are (precise but expensive) Linked Data Fragments.
>> - Data dumps are (huge but straightforward) Linked Data Fragments.
>> Between those two extremes, an underexplored range of fragments exists.
>> We propose a new type called "basic Linked Data Fragments",
>> which partitions a dataset in all its basic triple patterns.
>> This reconciles the need for queryable public datasets
>> with the availability demands of Web applications.
>> A basic Linked Data Fragments server with well-known datasets
>> is available online [3] (and so is its source code [4]).
>> Try our online client [5] that answers SPARQL queries
>> using only basic Linked Data Fragments (source code [6]).
>> It works up to two magnitudes faster than Linked Data Querying [7]
>> because servers offers those fragments that assist client-side querying -
>> without needing to solve expensive queries at the server side.
>> Basic Linked Data Fragments are not a definitive answer;
>> there are many other types of fragments to explore.
>> However, you might be surprised to see quite acceptable query times,
>> and - most importantly - high availability and scalability.
>> Read more on Linked Data Fragments on the website
>> http://linkeddatafragments.org/ and discover all details
>> in our forthcoming LDOW2014 publication [8].
>> Looking forward to your feedback!
>> Best regards,
>> Ruben Verborgh
>> Ghent University - iMinds, Belgium
>> [1] http://sw.deri.org/~aidanh/docs/epmonitorISWC.pdf
>> [2] http://linkeddatafragments.org/
>> [3] http://data.linkeddatafragments.org/
>> [4] https://github.com/LinkedDataFragments/Server
>> [5] http://client.linkeddatafragments.org/
>> [6] https://github.com/LinkedDataFragments/Client
>> [7]
>> https://cs.uwaterloo.ca/~ohartig/files/Hartig_LDQueryExec_DBSpektrum2013_Preprint.pdf
>> [8] http://linkeddatafragments.org/publications/ldow2014.pdf
>> Great stuff!
>> It certainly goes a long way towards making Linked Data's follow-your-nose
>> pattern easy to exploit, across SPARQL endpoints. Same applies to anyone
>> trying to construct their own pathways over SPARQL endpoints etc..
>> --
>> 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
Received on Wednesday, 19 March 2014 11:58:42 UTC

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