Virtuoso and LODRefine – more vicious than virtuous pair (part 2)

First…

there was a big black hole (BBH). And then it got bigger. Seriously. At this point in my life I realized that more I learn more is there to learn.

Failure is success if we live to learn from it.
(Malcolm Forbes and me)

Second…

Chewing through the virtuoso documentation made me realize that using /sparql endpoint for updating graphs (i.e. inserting triples into it) is not  a particularly good idea. One has to have some security, right? I said to the SPARQL user that it has the right to return error on any non-SELECT demand. I found out that there are three possibilities of securing your virtuoso endpoint:

There is good news…

Implementing  digest authentication into LODRefine was easy peasy (after I found the right library that is). I used Apache HTTP Client for this:


...
import org.apache.http.client.params.AuthPolicy;
import org.apache.http.NameValuePair;
import org.apache.http.auth.AuthScope;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.auth.UsernamePasswordCredentials;
...
...
...
  DefaultHttpClient client = new DefaultHttpClient();
  client.getCredentialsProvider().setCredentials(
	new AuthScope(endpoint.getHost(),endpoint.getPort()),
		      new UsernamePasswordCredentials(properties.get("username"), properties.get("password"))
		     );
  client.getParams().setParameter(AuthPNames.PROXY_AUTH_PREF, AuthPolicy.DIGEST);
  HttpPost httpPost = new HttpPost(endpoint.toURI());  try {
        List  nvps = new ArrayList ();
        nvps.add(new BasicNameValuePair("query", query));
        httpPost.setEntity(new UrlEncodedFormEntity(nvps));
        HttpResponse response = client.execute(httpPost);
        ...
      }
  ...
  ...

Nice and simple, if only the virtuoso endpoint you are trying to use supports this kind of authentication – if it does, it is accessible at /sparql-auth. I had to enable it on my local virtuoso instance. I also created a new user with SPARQL UPDATE rights. For more details see Virtuoso guide.

… and there is oh-not-so-good news …

In LOD2 we decided to use WebID authentication. This will definitely not be a walk in the park. You’ll have to wait for part 3 to see, whether I survived this dangerous endeavor.

Avoiding danger is no safer in the long run than outright exposure. The fearful are caught as often as the bold. Especially if they don’t run fast enough.
(Hellen Keller and me)

Virtuoso and LODRefine – viciously virtuous pair (part 1)

Disclaimer

I’m assuming that you :

  • are familiar with the notion of linked data (triples, SPARQL endpoints)
  • have heard about Virtuoso Universal Server,
  • want to give LODRefine a chance and,
  • don’t mind waiting for part 2 of this post.

The beginning…

They: “We want to upload triples directly from LODRefine to Virtuoso.
Me: “A wha?

… and the (almost) joke

A Virtuoso, SPARQL, and SPARUL enter the bar.
Bartender: “Hey guys, what can I get you?
They: “Select ?drink where {?drink <http://www.w3.org/1999/02/22-rdf-syntax-ns#label “Martini (Coctail)” }
Bartender (puzzled): “Gesundheit!? 

But seriously!

If you are familiar with LODRefine, then you know you can transform your data to triples using RDF extension (thanks to Fadi Richard from DERI!). Now what? You can export triples to file and then upload this file to some triple store.

Imagine you could insert triples directly from LODRefine. Guess what? This is exactly what I’m working on right now. Yay me! :)

I started with installing Virtuoso Open-Source Edition (OS X 10.7) and (fortunately) had no problems building, configuring and installing it according to the instructions. After adding SPARQL_UPDATE rights to the SPARQL user I was ready to insert some triples. And I did… insert some triples via /sparql endpoint. Lovely!

At this point (not endpoint) I learned about SPARUL (could be a name of a villain in the next Batman movie) and figured out how to delete all named graphs containing a specific substring in their name. Why I wanted to do this? Because I installed demo, sparql demo and what-not … and shortly after realized I would be much happier person without all these graphs in my virtuoso instance and that I don’t want to click on each and every one of them to remove them.

[In Vonnegut’s  Breakfast of Champions style…]

This is how you can remove all the graphs containing specific substring in IRI:


DELETE {GRAPH ?g {?s ?p ?o}} 
WHERE {
   GRAPH ?g {?s ?p ?o}  
   FILTER( contains(str(?g), "your substring here"))
}

Level 1: install instance of Virtuoso locally finished.

Next level: add “Upload data to triplestore” to LODRefine…

 

 

Enhanced by Zemanta

When CubeViz meets statistical data

It is time for the next free webinar in the LOD2 webinar series: CubeViz – a facetted browser for statistical data. The webinar starts on May 28, 2013 at 4:00 PM CEST.

In this one hour webinar Michael Martin (University of Leipzig, AKSW) will present CubeViz – a facetted browser for statistical data utilizing the RDF Data Cube vocabulary which is the state-of-the-art in representing statistical data in RDF. Based on the vocabulary and the encoded Data Cube, CubeViz is generating a facetted browsing widget that can be used to filter interactively observations to be visualized in charts. Who doesn’t like charts instead of raw (linked) data? :)

 

So… If you are interested in Linked (Open) Data principles and mechanisms, LOD tools & services and concrete use cases that can be realised using LOD then join us in the free LOD2 webinar series!

Do not forget to register here: https://www4.gotomeeting.com/register/687215863

Enhanced by Zemanta

European Data Forum 2013 – your data, our data, Big Data!

This year April will start Big… big as in Big Data, especially in Dublin, Ireland. LOD2 is one of the main organizers of a special event: on April 09-10,2013 Dublin hosts European Data Forum – EDF2013, an annual meeting place for industry, researchers, policy makers, and community initiatives, where they will be able to discuss the challenges and opportunities of (Big) Data in Europe.

‘The amount of data in our world has been exploding, and analysing large datasets — so-called big data — will become a key basis of competition, underpinning new waves of productivity growth, innovation, and consumer surplus.’ (McKinsey Global Institute, May 2011)

These challenges and opportunities around big data management, the single steps of the data value chain, technological innovations and innovative business models, as well as the legal framework for a sustainable European data economy will be discussed at EDF 2013.

Prestigious hardcore keynote speakers from Statoil, Telefonica Digital and Erricson will talk about Linked Data, Open Data, Big Data — you name it –, a moderated CIO discussion panel with selected experts will take place and comprehensive exhibition area is open to everyone willing to share and showcase their advances in solving real-world Big Data challenges. Check the call for Exhibits.

Registration and participation is free of charge. There is also an opportunity for financial travel support (mainly for SMEs and NGO/NPO) – please see the respective EDF2013 website for further details.

 

European Data Innovator Award

If you are an outstanding enterprise or individual

“… who have shown extraordinary vision and execution in the field of linked enterprise data management for their use of linked (open) data to start more efficient data management”

you might get the European Data Innovator Award, which was made possible by eccenca, a spin-off of Brox IT Solutions and AKSW Research group from University of Leipzig. More details here.

Are you the one?

 

Important facts, bits and dates

Location: Croke Park Conference Centre in Dublin, Ireland
Date: April 9 to 10, 2013
More Information: http://2013.data-forum.eu/

Registration 

Registration (EDF2013 is free of charge): http://2013.data-forum.eu/news/european-data-forum-2013-call-contribution/registration

If you would like to attend better register today (i.e. ASAP). Space at EDF 2013 is limited to 300 participants and more than 50% of tickets are already booked.

 

Contact, share, communicate

Twitter: https://twitter.com/EUDataForum , hashtag: #EDF2013

Press Area: http://2013.data-forum.eu/about/press-area

LinkedIn Group: http://www.linkedin.com/groups/European-Data-Forum-4356346
Get in touch: edf2013@data-forum.eu

 

Organizers

The European Data Forum 2013 is a joint activity of the EC projects:

The EDF2013 is supported by the European Commission as well as by the Digital Repository of Ireland (http://www.dri.ie/), STI International (http://www.sti2.org/) and DERI, NUI Galway (http://www.deri.ie/).  EDF2013 is an associated event of the Irish Presidency of the Council of the EU (http://www.eu2013.ie/).

 

2nd release of LOD2 technology stack

LOD2 project consortium announced new LOD2 technology stack release – a set of free tools, services and activities  serving one common purpose: creating knowledge out of interlinked data.

Linked Open Data Lifecycle

Linked Open Data Lifecycle (Photo credit: haschek)

The project coordinator Dr. Sören Auer states that “in a world of an emerging new data economy innovative and scalable mechanisms and technologies are needed to solve the arising data management problems – we see that lots of organisations are seeking for state-of-the-art data publishing and integration technologies along the whole data value chain to be able to efficiently use this growing amount of data. The efficient handling of data – available inside of organisations as well as on the internet – becomes more and more important to reach competitive advantage.

LOD2 tool stack at your service: supporting every step in the Linked Open Data Lifecycle.

This 2nd release of the stack contains updates to the components:

  • Ontowiki,
  • Silk,
  • SigmaEE and
  • Virtuoso,

but also some new components:

  • SPARQLED (by DERI),
  • LOD enabled OpenRefine (by Zemanta),
  • extended version of Silk (University of Mannheim) with link suggestion management from LATC (by DERI),
  • rdfAuthor library (by ULEI) and
  • SPARQLPROXY (by ULEI)

LOD2 stack is organized as a Debian package repository and can be relatively easy installed on any Debian-based system (yes, Ubuntu is one of them) or you can try it in an online demo or experiment with it on a virtual machine (you’ll need free VMware player).  In case you need some help with installation, you can also check How-to document with more details and instructions.

Hold on, there’s more.

Next webinar is all about this 2nd release of the LOD2 Stack on December 12, 2012 at 4pm CET. More information and registration are available here.
Join us and the may the LOD force will be with you.

Enhanced by Zemanta

Information and publishing industry get ready for Linked Open Data!

I’m glad to announce another free one-hour  LOD2webinar, this time it’s about “Linked Open Data in information and publishing industry”. Webinar will be presented by Wolters Kluwer Deutschland GmbH on November 19, 2012, at 4pm CET.

One of the main problems in publishing industry is information overload on one hand and scarce resources giving meaning to information on the other hand. Wolters Kluwer is a LOD2 partner from industry and they provide an use case how LOD and Semantic Web may/can solve this problem for their business. Presentation will guide you through different parts (tools) of the LOD2 stack, which are being used in their use case and expose the challenges that had to be addressed in the last two years. The topics covered are relevant for any industry that deals with a lot of data and documents, not only publishing.

What: LOD2 in information and publishing industry
Who: LOD2 project, presenter: Wolters Kluwer Deutschland GmbH
When: November 19, 2012, 04.00pm – 05.00pm CET
Information & Registration: https://www2.gotomeeting.com/register/853703530

The LOD2 team is looking forward to meeting you at the webinar!

Enhanced by Zemanta

Exploring the land of links: meet LIMES in the next LOD2 webinar

It’s been a while since I last posted about LOD2. This doesn’t mean nothing is going on… on the contrary! We are working hard to make a life LOD users a bit easier. I could go on and on about this, but I won’t… not yet. This time I’d like to announce the 5th free LOD2 webinar about the tools in LOD2 Stack. Missed previous ones? You can find info about them on the LOD webpage.

Interested? Continue reading (the official text).

——

LOD2 Webinar: LIMES

The 1st version of the LOD2 Stack has been published in September 2011 in the form of a LOD2 Stack demo and the downloadable LOD2 Stack virtual machine image – additional details and the instructions on installing the LOD2 Stack from scratch are available in the HOWTO Start document.
Born from the wish to make linking tractable, the (LIMES) is tailored towards the time-efficient and lossless discovery of links across knowledge bases. LIMES is an extensible declarative framework that encapsulates manifold algorithms dedicated to the processing of structured data of any sort. Built with extensibility and easy integration in mind, LIMES allows implementing applications that integrate, consume and/or generate Linked Data. Within LOD2, it will be used for discovering links between knowledge bases.

LIMES dashboard (image from their official page)

This webinar will be presented by the LOD2 Partner: University of Leipzig (ULEI), Germany.
The LOD2 webinar series is powered by the LOD2 project organised and produced by the Semantic Web Company(Austria). If you are interested in Linked (Open) Data principles and mechanisms, LOD tools & services and concrete use cases that can be realised using LOD then join us in the LOD2 webinar series! The LOD2 team is looking forward to meeting you at the webinar!!

When : 27.03. 2012, 04.00pm – 05.00pm CET
Information & Registration: https://www2.gotomeeting.com/register/369667514
The LOD2 team is looking forward to meeting you at the webinar!!
——

About the LOD2 Stack

The LOD2 stack is an integrated distribution of aligned tools which support the life-cycle of Linked Data from extraction, authoring/creation over enrichment, interlinking, fusing to visualization and maintenance. The stack comprises new and substantially extended existing tools from the LOD2 partners and third parties. The LOD2 stack is organized as a Debian package repository making the tool stack easy to install on any Debian-based system (e.g. Ubuntu). The first release of the LOD2 stack contains the following components (available as Debian packages):

  • LOD2 demonstrator, the root package (LOD2)
  • Virtuoso, RDF storage and data management platform (Openlink)
  • OntoWiki, semantic data wiki authoring tool (ULEI)
  • Silk, interlinking engine (FUB)
  • D2R, RDF wrapper for SQL databases (FUB)
  • ORE, ontology repair and enrichment toolkit (ULEI)

As online services were integrated into the LOD2 Stack: PoolParty (taxonomy manager by SWCG) and Spotlight (annotating texts w.r.t. DBpedia by FUB). The LOD2 Stack also makes use of dataset metadata repositories such as thedatahub.org and http://publicdata.eu. A selection of the datasets has been packaged and are available in the LOD2 stack repository.
The LOD2 stack is an open platform for Linked Data components. We are happy to welcome new components. Detailed instructions how to integrate your component into the LOD2 Stack as Debian package are available in the HOW-TO-CONTRIBUTE. For assistance or any questions related to the LOD2-stack contact support-stack@lod2.eu. From now on we will regularly release improved and extended versions of the LOD2 Stack. Major releases are expected for Fall 2012 and 2013.

More information about the LOD2 Stack
Demo: http://demo.lod2.eu/lod2demo
Virtual Machine Image: http://stack.lod2.eu/VirtualMachines/
How To Document: How to Start.

What’s next – the LOD2 webinar series

The LOD2 webinar series offers several (one per month) free webinars about Linked Open Data tools and services around the LOD2 project, the LOD2 Stack and the Linked Open Data Life Cycle, also in the form of 3rd party tools.
The next 2 dates of the LOD2 webinar series are already fixed as follows:

About LOD2 – Creating Knowledge out of Interlinked Data
LOD2 is a large-scale integrating project co-funded by the European Commission within the FP7 Information and Communication Technologies Work Programme (Grant Agreement No. 257943). Commencing in September 2010, this 4-year project comprises leading Linked Open Data technology researchers, companies, and service providers (15 partners) from across 11 European countries (and 1 associated partner from KOREA) and is coordinated by the AKSW research group at the University of Leipzig, Germany.
LOD2 will integrate and syndicate linked data with large-scale, existing applications and showcase the benefits in the three application scenarios of media and publishing, corporate data intranets and eGovernment. The resulting tools, methods and data sets have the potential to change the Web as we know it today.
More information about LOD2
Web: http://lod2.eu
Blog: http://blog.lod2.eu
Slideshare: http://www.slideshare.net/lod2project
Twitter: @lod2project , #lod2
flickR: http://www.flickr.com/photos/lod2/

 

 

Enhanced by Zemanta

What has LOD2 to do with OntoWiki … and me?

English: The following diagram visualizes the ...

Image via Wikipedia

It is time to announce (another) webinar from LOD2 webinar series, this time about OntoWiki.

But first things first…

In September last year I joined Zemanta (allright!) as a researcher… and Zemanta is a partner in a FP7 project called Linked Open Data 2 – Creating Knowledge out of interlinked Data. I already wrote about LOD2 in one of the posts on our blog (you can check it out here).

Upcoming webinar is just one of the webinars in the series describing tools released as LOD2 Stack – tools that will help you (and us) create, enrich, interlink and visualize open data. First webinar (November 2011) was in an introduction to LOD2 Stack, while second one  (December 2011) presented Virtuoso universal server for linked open data.

If you think this has nothing to do with you, think again. :) We all can contribute in this way or another to create new knowledge, better data and share it with others. There are already a bunch of cool projects related to Open data (ever heard about Freebase? Or DBpedia?) and contributing to “open things” it’s a good idea. :)

Back to announcement…

On January 24, 2012 @ 4p.m. you can participate in third free LOD2 webinar about OntoWiki. OntoWiki is a tool providing support for agile, distributed knowledge engineering scenarios. It enables intuitive authoring of semantic content, it supports RDF, it fosters social collaboration and much more.

Date: 24.01. 2012, 04.00pm – 05.00pm CET
Information & Registration: https://www2.gotomeeting.com/register/772475346

More information about webinar and registration: LOD2 webinar page.

It’ll only take one hour but it might change the way you see data for ever… ok, for now :)

Enhanced by Zemanta