Tag Archives: Web of Data

Tassilo Pellegrini

LOD2 Kick Off Meeting in Leipzig

by , Category: Linked Data & Open Data

From September 6 – 8, 2010 we kicked off the LOD2 project in Leipzig / Germany. LOD2 is funded by the European Commission within the 7th Framework Programme (Grant Agreement No. 257943) consisting of 10 partners from 7 countries. Its main aim is to integrate and syndicate linked data with large-scale, existing applications and showcase the benefits in three application scenarios: 1) Media & Publishing, 2) Enterprise Data Management and 3) Open Government Data. The resulting tools, methods and data sets have the potential to change the Web as we know it today. (You can download the project flyer here.)

The first day was dedicated to the general introduction of the project partners which are Universität Leipzig (Germany), Centrum Wiskunde & Informatica (Netherlands), National University of Ireland in Galway (Ireland), Freie Universität Berlin (Germany), OpenLink Software (United Kingdom), Semantic Web Company (Austria), TenForce (Belgium), Exalead (France), Wolters Kluwer Deutschland (Germany) and Open Knowledge Foundation (United Kingdom). Below you see a picture of the kick off team.

During the morning of the second day a first introduction to the technical components took place. The picture below shows an abstraction of the LOD2 high level architecture.

Orri Erling and Hugh Williams from OpenLink introduced Virtuoso, which will be used as one of the storage technologies in the LOD2 stack. The second knowledge store technology will be MonetDB introduced by Peter Boncz from CWI. Both systems will also be used as a kind of benchmark laboratory for hosting and querying linked data.

Christian Bizer from FU Berlin talked about Silk and D2R. In combination they will be used to discover relationship and similarities between entities within different linked data sources – generally called identity resolution.

Giovanni Tummarello from DERI introduced Sindice and Sig.ma under the aspect of how to update, validate and reuse data that is available on the web and support the production of professional, collaboratively governed linked data especially for enterprise use. Beside that an important aspect will be how to handle the high amounts of generated data. So according to Giovanni scaling the infrastructure and the use of appropriate hardware will be central in bringing the Sindice index into enterprise stacks i.e. as an approach for lightweight data consolidation purposes.

Norman Heino from AKSW University of Leipzig introduced OntoWiki and Semantic Pingback. Ontowiki will be used at the interface layer for producing, annotating, browsing and querying linked data and presenting it to the enduser in various GUIs. Semantic Pingback’s aim is to interlink the Web 2.0 with the Semantic Web by backwards compatible RPCs (remote procedure calls). It detects new typed or untyped external links, manages the GET and POST commands and it takes care of server autodiscovery.

Andreas Blumauer from Semantic Web Company demonstrated PoolParty as a smart editor for metadata in enterprise stacks. Like Ontowiki PoolParty also addresses the interface level of LOD2 especially when it comes to generate, edit and link metadata to documents primarily based on SKOS. PoolParty deliberatelly uses Thesauri as a mapping layer to discover similarities of documents, generate tag recommendations for their annotation and publish used vocabularies as Linked Data.

In the afternoon we continued with individual breakout sessions to discuss work package interdependencies and start profiling the use cases and requirements eingineering in more detail.

The third day started with an introduction by Stefano Bertolo – the responsible scientific project officer from the EC side for the LOD2 project – who pointed out that the LOD2 project is an important one for the European Web of Data and the EC among others specially is interested in the Open Government Data use case of LOD2.

After this introduction talks of the 3 Use Cases were presented by A) Jonathan Gray (OKFN) about the Open Gov Data use case followd by B) Amar-Djalil MEZAOUR (Exalead) speaking about the Linked Business Data use case and C) Christian Dirschl (Wolters Kluwer) having a talk about the LOD in the publishing & media industry use case.

Central to the success of LOD2 will be a smart handling of all the integration issues which will come up in the course of the project. Here Tenforce, an integration specialist from Belgium, will have the lead. CEO Bastiaan Deblieck gave a detailed outlook on the methodologies  and he presented a nice and comprehensive overview how the integration issues will be approached from a SCRUM perspective.

After a presentation about LOD2 project dissemination, training and community building activities by Martin Kaltenböck (Semantic Web Company) there were serveral discussions going on until the successful kick off meeting was closed by project lead Sören Auer (Universität Leipzig) at 04.00pm of 08 September 2010.

Updated news information can be accessed on the LOD2 project website as well as on the LOD2project twitter stream (and on twitter using #lod2)…

Stay tuned!

Tassilo Pellegrini

Interview with Juan Sequeda: “I believe Linked Data will enable new killer apps that are only possible thanks to Linked Data.”

by , Category: Calls & Competitions, Linked Data & Open Data, Semantic Web Applications

Juan Sequeda, co-chair of the Triplification Challenge 2010 and one of the core figures in the Linked Data movement, gives us his view how the Semantic Web might evolve. His central message: “Once there is an incentive to create quality links, these links will start to show up. And then users will start linking to the data hubs of their interest.”

Linked Data itself has grabbed a lot of attention inside the Semantic Web community recently. But what about the outside perspective? Could linked data be called the killer app for the Semantic Web?

I foresee two things happening with Linked Data. One is from the web development perspective (the so-called Web 2.0 developers) and the other is from the enterprise perspective. The web development community will sooner than later realize that Linked Data will enable easy integration of data and therefore will ease the pain of consuming data from different data sources. Thanks to big organizations such as BBC, New York Times, Reuters, Best Buy, etc. web developers will start paying attention to this “new thing” called Linked Data.

What we need is that the inside Semantic Web community starts to create applications on top of current Linked Data so when the outside web development community starts to pay attention, they have something to chew on. We (the semantic web community) needs to start speaking the web development language. There is still a big gap. I have had personal experiences with people in the web development community who think that RDF is XML and because they hate XML, they will never consider it. This is false and this is something that we need to change.

From the enterprise perspective, Linked Data is another data integration solution. Data integration has been a problem since day one of relational databases. I believe enterprises will be open to consider new solutions with new technologies. I’m hoping to see new startups tackling the enterprise domain. Imagine being able to query “get all my clients from cities whose population is greater than 1 million” even though I don’t have the data about population of cities in my database.

Is Linked Data the killer app for the Semantic Web? Before I answer that, I would like to ask, what was the killer app of the Web? Was it the browser? Was it e-commerce? Was it search? Was it Amazon or Ebay or Google? I believe Linked Data will enable new killer apps, apps that are only possible thanks to Linked Data. The browser was only possible because of HTML. So let’s ask ourselves what is possible because of Linked Data, and there we will find our killer app.

One of the core deficiencies of the young open data cloud is the little amount of interlinks between datasets. Is it just a matter of time to overcome this or are there other measures needed to turn the existing datasets into a true giant global graph?

I like to remind myself that this new wave of semantic web technologies is an extension of the current web. Therefore we should analyze how the web evolved in the beginning. Initially, everything were a bunch of documents on the web in which people manually created links to other documents. When Google started, it created an incentive to offer quality links between documents. This also created data hubs. If you write a blog post about a book, most probably you will link to the web document of that book either on Amazon and/or Wikipedia. I believe that this will happen with Linked Data. Once there is an incentive to create quality links, these links will start to show up. And then users will start linking to the data hubs of their interest.

Open Governmental Data is a big issue at the moment. The US and UK government have started to apply Linked Data principles to turn this vision into reality. Lots of other countries are following. What do you expect from this trend?

I believe that Linked Data will take off thanks to the initiative of governments. We always talk about the chicken and egg problem of the semantic web. Once we have organizations that don’t even think about it and are just interested in putting their data on the web, the semantic web will start to grow. If Bookstore ABC puts their data on the web, it may not be so meaningful. But if the US and UK government puts their data on the web, following the Linked Data principles, then people can wake up and say “ok, so this is for real. Let me start paying attention to this”.

You are one of the chairs of the Triplification Challenge 2010. Can you give us a brief insight what to expect from this year’s challenge? What are the conditions to participate?

The Triplification Challenge this year has grown and is very exciting. For the first time, it is offering two different tracks.

The first track, the Open Track will accept submissions on three areas 1) new datasets that are published following the Linked Data principles and that show potential benefit, 2) generic methods, mechanisms and approaches of creating Linked Data from legacy datasets and 3) applications that make use of Linked Data.

The second track is the New York Times track which will accept submissions of applications that make use of the New York Times Linked Data and one or more government dataset. The objective is to create an application powered by Linked Data that would be of interest to any constituent of that government.

I personally believe that the year 2010 is the year of creating Linked Data applications and the Triplification Challenge is the way to be part of it.

Tassilo Pellegrini

Interview with Georgi Kobilarov: “I believe that data publishing must happen in a distributed style.”

by , Category: Linked Data & Open Data, Mashups & Web services, Semantic Web Applications, Tools & Software

Uberblic.org connects structured data from the web. The Berlin-based inventor Georgi Kobilarov gives a brief insight into the mashup service and talks about the challenges when it comes to build applications upon linked data.

You have recently published the service uberblic.org, a Linked Data mashup editor. What was your motivation to develop this tool?

Uberblic.org provides an integrated view of web data. Our goal is to integrate all the structured data on the web, and give web-developers a single point to access to that reconciled data. More than that, we will open up the tools we use to manage the data sources to the community, so that the people can help us curating that repository of free data. We re-publish all the data we import as Linked Data, under the licenses of the original data publishers.

Some of the data sources we import are available in the Linked Open Data cloud as well, but many are not. Linked Data is an elegant way to publish data in a distributed way on the web, but consuming it from that distributed cloud is – at least – impractical. In every real-world application using linked data from the web I’ve seen, organizations built up internal copies of the cloud, and often even reconcile linked data sources. They build their own Linked Data proxies. Uberblic.org helps those users by providing one public proxy for data from the web. Many of our sources get monitored for data changes, and the according data in uberblic is updated in real-time.

uberblic

Can you give us a brief insight how the tool works? What technology is is built on?

My company, Uberblic Labs, has developed a data integration platform that we use to power uberblic.org. We call it the Uberblic Platform (the name uberblic is derived from the German “Überblick” – English “overview”). This platform enables us to do the full process of “data fusion”: Importing and converting external data sources, mapping the data schemas to a central ontology, filtering out data errors, automatically suggesting duplicates to the user, and merging data from different sources into a single, reconciled representation.

Structured and semi-structured data from the web is an excellent use case for our software platform, since there we come across all the interesting cases of real-world data heterogeneity. But what I think is especially powerful and yet missing in other Linked Data projects I know, is the ability to subscribe to update-feeds. We do that extensively, fetching updates in real-time from Wikipedia and the like.

Our platform is built in Scala and runs a on cluster of machines, with workers communicating through a messaging system. We developed an RDF storage layer on top of a distributed key-values store for storing all provenance information used in the extraction process, currently around 100 million named graphs for uberblic.org. That storage layer does not directly provide SPARQL access, so we push all the output data into a SPARQL endpoint hosted by Talis as well.

What have been the biggest challenges in tackling the integration issues of dispersed data?

It was quite a steep learning curve to do Linked Data not only in an academic environment, but in a reliable, industry-strength set-up. In academia, there was always the excuse that things are just research prototypes. Now that excuse is gone. That’s also where it becomes necessary to manually clean up data. And there are two ways to do that: Either you enable the users to change facts directly in your repository after you have imported the external data (that is what Freebase does), or you facilitate clean-up cycles in the original data source and fetch these updates in real-time. That is what we do.

I believe that data publishing must happen in a distributed style, because then each data source gets taken care of by a specialized group of people using specialized tools. And it’s what you see not only on the web, but also inside organizations and enterprises. But consuming data trough centralized APIs is more than just convenient. We all use Google
or another search engine as a central access point to web pages which are published in a distributed way all over the web, don’t we? Can you imagine today researching a topic on the web without the centralization power of search engines, just by following links across web sites, like in the old days?

When we built the Uberblic Platform, some of the things I imagined to be large headaches, like schema mapping, turned out to work really well. Those pathologic cases you often see in academic “challenges” are – well – pathologic. It’s not necessary to solve them fully automatically through super-intelligent algorithms. Much more important than the sophistication of your algorithms are well designed workflows so that the user becomes a part of the solution. And that’s not about crowd-sourcing or swarm intelligence, the editorial curating of schema mappings and object reconciliation can be done just by a small team of people. If they have the right set of tools.

What are the next plans with uberblic.org? Where will the journey go?

Uberblic.org will continue to integrate more interesting and useful data sources from the web, and we will start making more APIs available to web developers to build their applications on top. We are also looking for partners who are interested in developing applications and have been struggling in the past to get the cross-source data from the web they need.

The work on improving uberblic.org will also benefit our Uberblic Platform, and hence our clients who use that same software for integrating organizational data sources with each other and with the web of data.

About Georgi Kobilarov

Georgi is founder and managing director of Uberblic Labs, a company based in Berlin specialized in Linked Data integration. He worked as a research associate in the Web-based Systems Group at Freie Universität Berlin and as a visiting researcher at Hewlett Packard Labs Bristol. As co-founder and lead developer of DBpedia, he was also a day-one contributor to the Linking Open Data project. Georgi is consulting with the BBC on several Linked Data related projects. He organizes the Web of Data Meetup London, a bi-yearly gathering of the UK Linked Data community. Georgi graduated with a Diplom in business administration from Freie Universität Berlin and has many years of work experience as a software developer. Visit his blog: http://blog.georgikobilarov.com

Tassilo Pellegrini

Linked Data Flows: A new picture to illustrate the “openness” we mean

by , Category: Corporate Semantic Web, Linked Data & Open Data

(Original post taken from “About the Social Semantic Web“)

A lot of activities around Linking Open Data (“LOD”) and the associated data sets which are nicely visualised as a “cloud” are going on for quite a while now. It is exciting to see how the rather academic “Semantic Web” and all the work which is associated with this disruptive technology can be transformed now into real business use cases.

What I have observed in the last few months, especially in business communities, is the following:

  • “Linked Data” sounds interesting for the business people because the phrase creates a lot of associations in a second or two; also the database crowd seems to be attracted by this web-based approach of data integration
  • “Web of Data” is somehow misleading because many people think that this will be a new web which replaces something else. Same story with the “Semantic Web”
  • “Linking Open Data” sounds dangerous and not trustworthy to many companies

For insiders it is clear, that the “openness” of data, especially in commercial settings, can be controlled and has to be controlled in many cases i.e. by defining the right licensing models. But here we are still at the beginning as a workshop at ISWC 2009 has illustrated.

Anyway, looking at the characteristics of Linked Data Flows, they can be one-way or mutual. In some cases data from companies will be put into the cloud, and can be opened up for many purposes, in other use cases it will stay inside the boundaries. In other scenarios only (open) data from the web will be consumed and linked with corporate data, but no data will be exposed to the world (except the fact, that data was consumed by an entity).

And of course: On many other occasions datasets and repositories will be opened up partly depending on the CCs (or similar, not yet defined attributes) and the underlying privacy regulations one wants to use.

This makes clear that LOD / Linking Open Data is just one detail of a bigger picture. Since companies (and governments) play a crucial role to develop the whole infrastructure, we need to draw a new picture that illustrates the various Linked Data Flows in a better way:

linkeddataworld

Concluding from this the best thing would be to talk about Linked Data in general and just refer to Linking Open Data in the right context. Despite better knowledge for business people the term  “open” is still associated with “free” and “dubious provenance”. And given the fact that hardly anybody has given hard evidence on the ROI of open business models the “open argument” does count little in a time of decreasing economic prosperity.

So what would be critical to get the Linked Data thing running is to provide the corresponding business and licensing models for your Linked Data strategy. But this includes having a good understanding of the assets you want to capitalize. Given the fact that metada assets are still a novel and vastly unexplored business field which so far lack a regulated supply and demand structure there are still lots of structural obstacles that hinder the uptake of Linked Data. Providing more of the same in a laissez faire mode – like TimBL critisized at this year’s Web 2.0 Summit – might be inspiring for the in-crowd, but it might not be sufficient to build a linked data business.