Semantic Web Company

There’s a lot to know about semantic standards, languages, technologies and their application, so last week I attended TopQuadrant’s first European training from Oct 5th to 9th in Amsterdam.

We kicked off with Eddy Vanderlinden elaborating on the lessons he learned from 30 years of work in the financial sector. He outlined how improvements could be achieved by using data models relying on semantic web standards. You can read about his ideas in this essay.

TQ’s chief scientist Dean Allemang then continued with his talk “Enabling Creativity at the Edge”. “The edge” refers to the boundary between an information system and the real world, where the end users of a system work. As business needs change faster and faster, the people working at the edge need to be able to adapt the company’s applications on their own and shape them to their everyday needs.

Dean Allemang

Nowadays end user often achieve this kind of creativity on the edge by using self-made spreadsheets. The problem with that is their lack of interoperability. These data from different spreadsheets, databases, reports, etc. are often connected through business processes that rely on repetitive and error prone human processing, like copying things from a spreadsheet to a database, creating a report and pasting its result into another system, and so on.

The result is a complex system with many heterogenous parts and an organisation that cannot possibly know what it knows.

As a solution Dean proposed to “think outside the table” and go beyond the relational database way of orgranising data. This of course can be achieved by integrating the data using semantic technologies. TopQuadrant’s software offers possibilities to do just that, and makes it possible to create highly customizable dashboards and applications that all rely on the same data.

During the following days we learned about the ins and out of using semantic standards and languages and tried out TopBraid tools in several hands-on excercises. The TopBraid Suite is a very powerful, commercial toolkit. It includes TopBraid Composer, Live and Ensemble. Composer is a semantic web modeling and application developement tool, that uses the Eclipse framework. TopBraid Live is a server for semantic applications built with TopBraid Ensemble. Ensemble is a graphical application assembly toolkit, that enables end users to create custom apps that run in a browser and use RDF data and data models – thereby allowing for the above mentioned “creativity at the edge”.

I am very impressed with the capabilities of these tools, they enable the user to realize manifold possibilities that come with using semantic web standards – and that without programming. You can see some of these tools in action and learn about applying semantic standards in a series of webcasts from Semantic Universe. For the latter topic you might also attend one of our webinars.

On the last day Dean coverd several case studies, like connecting ontologies to legacy data sources (using e.g. D2RQ inside Composer), applying semantic technologies to the customer service management of a larger retailer or using ontologies in Federal Enterprise Architecture.

All in all I am very happy to have attended TopQuadrant’s training and hope they will establish a successful series of trainings in Europe just as they did in the US.

OWL 2 is in the final stages of becoming a W3C recommendation – as announced today. This means that the revision 2 of the Web Ontology Language should basically be stable now, only final fixes are expected. The OWL 2 Document Overview is the general entry point.

Pascal Hitzler

The Annual (German) AI Conference goes semantic: In 2009 there’s an “Ontologies & Semantic Web” track, Franz Baader and Frank van Harmelen are invited speakers, and there’s a tutorial on OWL 2 and Rules.

As a special treat, there’s also going to be a Mashup Challenge – which promises to be a fun event.

• Dates: September 15 – 18, 2009
• Location: Paderborn, Germany
• Paper submission: April 26, 2009
• Mashup Challenge Deadline: July 15, 2009

[Pascal Hitzler]

Andreas Blumauer (Semantic Web Company) talked with Brian Donnelly about a new system on the market called “Semantic Discovery System” (SDS), which helps to do sophisticated queries across existing datasets. Also talking why complex scripts or triple stores should not be exposed to the end-users anymore.

SDS is doing, what semantic web enterprises promised for years: An application that allows users to formulate sophisticated questions on their datasets and getting back data without writing SQL statements or going down to OWL concepts.

SDS leave the data in its orignal format and doing no transformation into triple stores. And then give the user through a graphical desktop software – with the use of OWL and SPARQL – the possibility to formulate questions on this datasets. So this is a software engine that focuses “at business people with a tool as easy to use as Excel or Mind Manager – with zero need to know or care about OWL, SPARQL” as Donnelly explains.

The next times will show if Donnelly’s “Semantic Discovery System” may be a semantic web killer application. In any case it seems to be a good step in bringing semantic technologies out of the teccie’s corner onto the desktops of business users.

Read the full interview at www.semantic-web.at

Bernardo Cuenca Grau, Ian Horrocks, Boris Motik, Bijan Parsia, Peter Patel-Schneider, and Ulrike Sattler. OWL 2: The next step for OWL. J. of Web Semantics, 2008.
Download (PDF, 248 KB)

Abstract:
Since achieving W3C recommendation status in 2004, the Web Ontology Language (OWL) has been successfully applied to many problems in computer science. Practical experience with OWL has been quite positive in general; however, it has also revealed room for improvement in several areas. We systematically analyze the identified short-comings of OWL, such as expressivity issues, problems with its syntaxes, and deficiencies in the definition of OWL species. Furthermore, we present an overview of OWL 2—an extension to and revision of OWL that is currently being developed within the W3C OWL Working Group. Many aspects of OWL have been thoroughly reengineered in OWL 2, thus producing a robust platform for future development of the language.

I’m not going to explicitly comment on the panel discussion at ISWC08, entitled An OWL 2 Far? Let’s simply say it was controversial. I don’t mind controversial panels. In fact, I think that few things are more boring than a panel where all panelists more or less agree. But at the same time, at the ISWC08 panel, I think, an important message got lost, namely that we really need reasoning for the Semantic Web, and that we need diversity in reasoning. (Admittedly, some people said so, but I think the message didn’t really get through.)

So, instead, let me give you some web search problems. They all came up in my real life, so they are not artificially created. It seems to me that the Semantic Web should make answering them easier, but with the existing web resources, they are really difficult.

• Find all papers having received best paper awards at ISWC conferences. I did that today, and it took me more than 30 minutes. And I’m not sure if I got all of them – indeed I would have missed one of them if I hadn’t known beforehand about that specific paper having received the award. Isn’t this a typical Semantic Web problem? (The results of my search are further below.)
• There’s an owl-like bird in southern German woods, and in colloquial german it’s called Käuzchen. Try to find out the english name for this bird. I actually failed, though I think I got close to the answer when I merged web search with an external knowledge base (in form of a biologist I happen to know). And actually, simply going to Wikipedia and clicking on the English link is not enough, since I’m not looking for the Strix genus of owls, but rather for a particular bird …
• Who is this researcher with the russian looking name who worked on resolution-based methods for the description logic EL? This also looks like a typical Semantic Search problem, which shouldn’t be too difficult if you have the corresponding knowledge (and background knowledge) available. I admit I failed on this one using traditional methods (unless you consider it a traditional method to ask Franz Baader by email about it.)
• Are lobsters spiders? I.e. are lobsters classified as spiders by biologists? This one is actually tougher than you would think using traditional methods. Should be easy using Semantic Web knowledge bases and some simple reasoning, shouldn’t it?

For all these tasks (and many others), it seems to be apparent that Semantic Web Reasoning – and the availability of corresponding knowledge bases – would make the finding of answers much easier. The current reality of the Semantic Web is still quite a bit away from this. But we’re working on it.

Finally, as promised, the results of my inquiry about the ISWC best paper awards:

• 2004: Y. Guo, Z. Pan, and J. Heflin, An Evaluation of Knowledge Base Systems for Large OWL Datasets.  This one compares different semantic web reasoners.
• 2005: The award was split that year. One half was awarded to P. Mika, Ontologies Are Us: A Unified Model of Social Networks and Semantics. The other half was awarded to B. Motik, On the Properties of Metamodeling in OWL. Edit: Apologies to Peter Mika. I accidently forgot his paper and mentioned instead a paper which won the best paper award at the International Symposium on Wearable Computers 2005, which is also abbreviated ISWC. It’s now been corrected. We definitely need Semantic Search!
• 2006: H. Chen, Y. Wang, H. Wang, Y. Mao, J. Tang, C. Zhou, A. Yin, Z. Wu, Towards a Semantic Web of Relational Databases: a Practical Semantic Toolkit and an In-Use Case from Traditional Chinese Medicine.
• 2007: D. Zeginis, Y. Tzitzikas and V. Christophides, On the Foundations of Computing Deltas Between RDF Models. This one is about a diff for RDF, and it involves RDF inferencing.
• 2008: M. Horridge, B. Parsia and U. Sattler, Laconic and Precise Justifications in OWL.

So why did I dig these awards out? Because I noticed that among these 6 papers there are 3 which are explicitly concerned with OWL. And the 2007 paper involves RDF inferencing. Talk about the importance of reasoning for the Semantic Web …

Author: Pascal Hitzler, AIFB, University of Karlsruhe (TH), Germany

As ISWC08 is drawing to a close, it dawns to me that something which Frank van Harmelen has been forecasting for years is now happening, seemingless without conscious effort. He calls it Approximate Reasoning – have a look at his ESWC06 keynote. The basic idea behind it is to do reasoning over ontologies with a different focus, namely by giving up some reasoning correctness in order to gain better scalability.

And indeed, at ISWC08 I have seen a number of things which fit exactly into this corner (while at the same time the authors/programmers might not even be aware of it).

• As part of the Billion Triple Challenge, Axel Polleres presented the SAOR system, which does approximate OWL reasoning by means of forward chaining rules. Now you can’t do OWL reasoning (in a sound and complete way) with forward chaining rules (and Axel knows this), so in the end you’re losing some consequences. But at the same time you do get some consequences when having to deal with large amounts of data.
• Eyal Oren, also at the Billion Triple Challenge, presented the MARVIN system which performs approximate RDF reasoning by means of massive parallelisation. MARVIN comes out of the EU project LarKC, which is actually pursuing approximate reasoning on a large scale (pun intended). Edit: This one actually won the 3rd prize at the challenge.
• Among the results presented at ISWC08, I found those by Claudia D’Amato on Statistical Learning for Inductive Query Answering on OWL Ontologies really amazing. She and her collaborators managed to do OWL instance retrieval without any deduction algorithm. Instead they used Support Vector Machines and learned which (named) OWL classes individuals belong to. The learning was done from a small sample set (generated by a reasoner), but the network was able to generalise from the data to achieve about 90% of coverage. In my opinion, this is something conceptually new and it is really remarkable that it works.
• In a regular paper Eyal Oren also reported on using Evolutionary Algorithms for RDF query answering.

The above is only a selection of approximate reasoning related things at ISWC08. There was also the Workshop on Nature inspired Reasoning for the Semantic Web where related ideas were discussed. At the colocated Web Reasoning and Rule Systems conference, RR2008, there will be two papers on approximate reasoning (incidentially, with me as coauthor).

I foresee the importance of such approaches rising substiantially in the future (and I think it’s a safe guess since Frank also seems to think so). The Billion Triple Challenge series could become one of the driving forums for this. There are exciting times ahead!

Author: Pascal Hitzler, AIFB, University of Karlsruhe (TH), Germany

I am sure you are aware that the Web Ontology Language OWL is currently undergoing a revision by the W3C OWL Working Group. The revised version will be known as OWL 2, and is going to feature some enhancements of expressivity, and will also designate tractable sublanguages (called profiles).

What is less known is that the current effort to revise OWL was in part driven by the workshop series OWL – Experiences and Directions (OWLED), where the initial proposal for the revision was discussed as early as 2005. The OWLED series has become a major forum for the OWL community, where practitioners in the industry and academia, tool developers and others interested in OWL can describe real and potential applications, share experience and discuss requirements for language extensions/modifications.

The next installment of the OWLED workshop, OWLED2008, has just released its call for papers. So if you have an opinion how OWL could or should be improved, consider writing a note and participate in the meeting and the discussions. The general chair of OWLED2008, Alan Ruttenberg, is actually also co-chair of the W3C OWL Working Group, which obviously isn’t just coincidence.

OWLED2008 is going to take place end of October 2008 in Karlsruhe, Germany, and is co-located with the International Semantic Web Conference (ISWC2008), and the conference on Web Reasoning and Rule Systems. So it’s going to be a good place to be to get up-to-date news on what’s going on in and around the Semantic Web.

Come share your expertise with linked data and semantic technologies and learn from others at LinkedData Planet in New York City (June 17-18, 2008).

In creating the modern generation of enterprise and web applications, we typically integrate information from multiple sources. Relating data from disparate sources presents a challenge of deriving information. However, semantic tools and technologies are evolving that enable us to understand information derived by linking data from different sources, including data from applications, databases, ontologies and content management systems. Semantic technologies and tools support techniques such as tagging online information to make it more readily accessible for data integration. This makes it easier to understand data in relation to other data, even if some of this data is inside your firewall, some is in a business partner’s system, and some is part of the growing collection of useful publicly available data on the web.

LinkedData Planet provides insights into those technologies that enableus to:

• connect data contained in silos within organizations in a meaningful way
• extract and correlate data from web sites and databases for purposes such as analyzing trends and decision support, customer and vendor relationship management, and social networking

(more…)

It has been half a year now that our German textbook on Foundations of the Semantic Web has appeared [1]. We received very positive feedback and see our book adopted for Semantic Web courses throughout the German speaking countries. We are particularly pleased that our concept seems to have worked out, i.e. our decision to focus on established standards which form the foundation of the Semantic Web instead of giving a shallow overview of the many Semantic Web topics which are not yet mature enough for applications.

In particular, our book introduces RDF, RDF Schema, and OWL in very detail, and does so in an intuitive manner. Separate from this are chapters explaining the formal semantics in terms of logical foundations for these languages in depth, including deduction algorithms. This is accompanied by a discussion of SPARQL and conjunctive queries.

The book is accompanied by a website which contains slides which are ready-to-use for lectures, as well as exercises and selected solutions.

We have received many requests for providing a similar book in the English language, and indeed we are already working on it. This will also include a discussion of the forthcoming revision of the OWL standard, OWL 2, formerly known as OWL 1.1.

Any feedback is very welcome.

[1] Pascal Hitzler, Markus Krötzsch, Sebastian Rudolph, York Sure: Semantic Web. Grundlagen. Springer 2008, ISBN: 978-3-540-33993-9