Valentin's Blog

We finally came round to write up our ideas on how to overcome the motivation and incentive problems for collaborative heavyweight knowledge formalization:

This paper argues for collaborative incremental augmentation of text retrieval as an approach that can be used to immediately show the benefits of relatively heavyweight knowledge formalization in the context of Web 2.0 style collaborative knowledge formalization. Such an approach helps to overcome the "Curse of Prepayment"; i.e. the hitherto necessary very large initial investment in formalization tasks before any benefit of Semantic Web technologies is visible. Some initial ideas about the architecture of such a system are presented and it is placed within the overall emerging trend of "people powered search".

You can read the entire paper here. I will present it at the INSEMTIVE workshop at this year's ISWC; if you're in Karlsruhe, it would be great to see you there!

Labels: publication, SemanticWeb, SOBOLEO

There is a considerable gap between the potential of rules bases to be a simpler way to formulate high level knowledge and the reality of tiresome and error prone rule bases creation processes.
Based on the experience from three rule base creation projects this paper identifies reasons for this gap between promise and reality and proposes steps that can be taken to close it. An architecture for a complete support of rule base development is presented.

A publication of mine accepted for this years ICEIS conference, you can read the whole thing here.

Labels: KBSDevelopment, publication

This paper argues that a significant part of today's Semantic Web research is still dominated by ideas from centralized databases. Furthermore, the main thread of reasoning research focusses on approaches that can never scale to anything similar to the Web. Starting from these negative observations we argue that emergent semantics and ontology maturing are more suitable approaches for dealing with ontologies on the Web. Similarly, a few approaches for more Semantic Web appropriate reasoning exist, but are in dire need of realistic use cases.

A paper by me, Andreas Abecker, Denny Vrandecic, Imen Borgi, Simone Braun and Andreas Schmidt; Denny will present it at the Workshop: "New forms of reasoning for the Semantic Web: scalable, tolerant and dynamic". The entire paper is here.

The paper reflects my frustration with the fact that a large part of Semantic Web research (in particular in Europe) is concerned with something like "Semantic Databases" and not even trying to tackle the challenges unique to the Semantic Web. The paper had a bit of a strange creation process and ended up being not very controversial, but I think its still useful, particular since it collects and orders references to innovative work related to the Semantic Web (as opposed to Semantic Databases). 

Labels: publication, SemanticWeb

A paper by the usual suspects (Andreas Walter, Simone Braun, Andreas Schmidt and me) about some evaluation results and our plans for future work surrounding the ontology maturing ideas.  It will be presented at the Workshop on Emergent Semantics and Ontology Evolution at the ISWC 2007.

Ontology maturing as a conceptual process model is based on the assumption that ontology engineering is a continuous collaborative and informal learning process and always embedded in tasks that make use of the ontology to be developed. For supporting ontology maturing, we need lightweight and easy-to-use tools integrating usage and construction processes of ontologies. Within two applications – Imagination for semantic annotation of images and SOBOLEO for semantically enriched social bookmarking – we have shown that such ontology maturing support is feasible with the help of Web 2.0 technologies. In this paper, we want to present the conclusions from two evaluation sessions with end users and summarize requirements for further development.

The entire paper can be downloaded here.

Labels: publication, SOBOLEO

In this paper we describe novel ideas and their prototypical implementation for the visualization of rule bases. In the creation of the visualization our approach considers not only the structure of a rule base but also records of its usage. We also discuss methods to address the challenges for visualization tools posed by rule bases that are large, created with high level knowledge acquisition tools or that contain low level rules that should remain hidden from the users.

My paper for the special track on knowledge visualization of the I-Know conference this fall. The entire paper is here. Its no rocket science, but I really think its something that's generally useful (for relatively small rule bases) and that hasn't been done before.

Labels: KBSDevelopment, publication

(Please excuse the German)

Bisher gibt es kein integriertes Werkzeug, welches sowohl die kollaborative Erstellung eines Indexes relevanter Internetressourcen („Social Bookmarking“) als auch einer gemeinsamen Ontologie, welche zur Organisation des Indexes genutzt wird, integriert unterstützt. Die derzeitigen Werkzeuge gestatten entweder die Erstellung einer Ontologie oder die Strukturierung von Ressourcen entsprechend einer vorgegebenen, unveränderlichen Ontologie bzw. ganz ohne jegliche Struktur. In dieser Arbeit zeigen wir, wie sich kollaboratives Tagging und kollaborative Ontologieentwicklung vereinen lassen, so dass jeweilige Schwächen vermieden werden und die Stärken einander ergänzen. Wir präsentieren SOBOLEO, ein System, das kollaborativ und web-basiert die Erstellung, Erweiterung und Pflege von Taxonomien und gemeinsamer Lesezeichensammlung ermöglicht und gleichzeitig die Annotierung von Internetressourcen mit Konzepten aus der erstellten Taxonomie unterstützt.

For once a German publication (this may be my first) about the relations between tagging and semantic annotations (and Soboleo). Its written by the usual people (Simone Braun, Andreas Schmidt and me) and will presented at the German Mensch und Computer conference by Simone.

It focusses on the question why you could want to augment tags with more structure. You can access the entire paper here.

Labels: publication, SOBOLEO

Another publication, it reflects on adoption of agile methodologies (in particular XP) for the use in the development of rule bases. I developed the ideas while writing an offer for a very interesting contract to develop some rule based system; still not decided whether we get the contract, but at least I got a paper out of it :)

Both reviewers gave it the highest possible score for readability - so if this topic interests you at all you can read the paper here.  

Recently, with the large scale practical use of business rule systems and the interest of the Semantic Web community in rule languages, there is an increasing need for methods and tools supporting the development of rule based systems. Existing methodologies fail to address the challenges posed by modern development processes in these areas: namely the increasing number of end user programmers and the increasing interest in iterative methods.

To address these challenges we propose and discuss the adoption of agile methods for the developments of rule based systems. The main contribution of this paper are three development principles for and changes to the XP development process to make it suitable for the development of rule based systems.

I'm the sole author and I'll be presenting it at the 16th International Conference on Information Systems Development (ISD2007) in Galway. The submitted version (still anonymous, the conference has a double blind review process) is here.

Labels: KBSDevelopment, publication

We present Explorative Debugging as a novel debugging paradigm for rule based languages. Explorative Debugging allows truly declarative debugging of rules and is well suited to support rapid, try and- error development of rules. We also present the Inference Explorer, an open source explorative debugger for horn rules on top of RDF.

By myself and Andreas Abecker.  I'll be presenting it at the Scripting for the Semantic Web Workshop at the European Semantic Web conference next week.

You can read the entire paper here, I think its actually quite readable and worth your time (if you have any interested in how to debug rules - that is).

I haven't really decided on how much further I develop this line of research and the implementation of this debugger - Hence I' ld love to hear any feedback concerning this ideas - think its worthwhile? waste of time? better debuggers exist already? Would use such a tool?

Labels: KBSDevelopment, publication

With the growing interest in rule languages in the Semantic Web and the Business Rule community it is time to look again at the issue of debugging rule bases. New challenges have arisen since the time most concepts for today's debuggers where created: end user programming has grown in importance, graphical editors have become more common and programs are increasingly interconnected. Today there is no debugger for rule-based systems that takes into account the declarative nature of rules and that addresses these challenges.

This paper proposes Explorative Debugging as a paradigm for building debuggers that truly take into account the declarative nature of rules. The Inference Explorer is presented as an implementation of the explorative debugging ideas.

A publication by me and Andreas Abecker that was accepted for this years SEKE conference (Nineteenth International Conference on Software Engineering and Knowledge Engineering). 

It is a paper more about the challenges for debugging and less about the solution ... I hopefully post a paper that concentrates on the core concepts of Explorative Debugging in a week or two (IF it gets accepted :)

The entire paper is here.

Labels: KBSDevelopment, publication

We present SOBOLEO, a system for the webbased collaborative engineering of SKOS ontologies and annotation of web resources. SOBOLEO enables the simple creation, extension and maintenance of taxonomies. At the same time, it supports the annotation of web resources with concepts from this taxonomy.

And another publication. I talked about SOBOLEO before, but now it got its own demo paper. SOBOLEO is a rather nice tool that brings together Semantic Search, a lightweight annotation tool (AJAX bookmarklet) and a collaborative real time taxonomy editor. In the coming days SOBOLEO (and all other demos) will also be available for the workshop participants to try out - I'm curious how that'll work out; how well it will be able to holds its own against the likes of collaborative Protégé and Bibsonomy (I always like it when the other approaches that you dismiss in the "related work" section are actually present at the same workshop :)

It's also published at the Workshop on Social and Collaborative Construction of Structured Knowledge @ WWW. Authors are the developers of SOBOLEO - Valentin Zacharias and Simone Braun. You can read the entire (demo) paper here.

Labels: publication, SOBOLEO

Most of the current methodologies for building ontologies rely on specialized knowledge engineers. This is in contrast to real-world settings, where the need for maintenance of domain specific ontologies emerges in the daily work of users. But in order to allow for participatory ontology engineering, we need to have a more realistic conceptual model of how ontologies develop in the real world. We introduce the ontology maturing processes which is based on the insight that ontology engineering is a collaborative informal learning process and for which we analyze characteristic evolution steps and triggers that have users engage in ontology engineering within their everyday work processes. This model integrates tagging and folksonomies with formal ontologies and shows maturing pathways between them. As implementations of this model, we present two case studies and the corresponding tools.

This paper was accepted to the workshop on Social and Collaborative Construction of Structured Knowledge @ WWW2007 (authors are Simone Braun, Andreas Schmidt, Andreas Walter, Gabor Nagypal and me). You can read the complete text here.

It got pretty good reviews, so you might actually want to read it :)

Labels: publication, SOBOLEO

I thought that only ever publishing accepted papers gives a wrong impression of my work (and probably those of many scientists). So, here: three papers that didn't get published (yet).

The Verification of Rule Bases - this I put together rather hastily for the PING symposium. It tries to describe the software engineering challenges posed by rule languages and how my dissertation addresses them. Didn't work out, apparently it was completely impossible to understand what I wrote. Luckily it was only an extended abstract so I'll just throw it away.

A Semi-Automatic Debugger for Subject Matter Experts (with Anthony Jameson) - well, the title says it all: a semi automatic debugger for F-logic, created for Project Halo. In this case the workshop where we submitted it to, AADEBUG, got canceled - not that many people interested in automated debugging systems these days (will change, these kind of tools really work better with Semantic Web languages than with procedural and object oriented languages). The things described in this paper are still valid and new - I'm still looking for a venue to publish it. Sadly the evaluation is (so far) to weak to have a chance at a decent conference.

Finally an ESWC submission about test driven development of rule bases by domain experts (together with Michael Erdmann and Anthony Jameson). This was a really annoying reject, because a lot of work went into the paper and the reviews where superficial at best. The paper had its limitations and submitting it to ESWC was a longshot, but still ... you didn't get the impression that the reviewers took the time to understand it.

And now, hopefully, the next publication posts only about accepted papers :)

Labels: publication

Another publication. Will be presented at the Workshop on Productive Knowledge Work : Management and Technological Challenges (ProKW), 4th Conference on Professional Knowledge Management - Experiences and Visions (WM 2007).

Authors are Simone Braun, Andreas Schmidt and me.

Ontology building is an important prerequisite for state-of-the-art semantic technologies for knowledge worker support. But ontology engineering methods have so far neglected the early phase of ontology building where a conceptualization only exists rather informally and underlies continuous evolution through collaboration and interaction within the community. We have to view ontology building as a maturing process that requires collaborative editing support and the integration into the daily work processes of knowledge workers. In spirit of current Web 2.0 applications, we present an AJAX-based lightweight ontology editor as a first approach to this problem.

I won't be at the conference, but the other two will be. My role in writing the paper was rather small anyway. I did, however, do most of the work in defining and implementing one "lightweight collaborative ontology editing tool" presented in the paper. A rather nice AJAX application. A collaborative editor for a subset of SKOS. The cool thing about the editor is that it really support truly collaborative work - Google Spreadsheet style;  i.e. two people can really change the same concept at exactly the same time and nothing will break. Users see almost realtime* updates of the changes other people do to the same taxonomy.

The paper is not yet online, but someday you'll find it here.

* depending on configuration and connection - but maybe a third of a second.

Labels: publication, SOBOLEO

A poster I presented at the 1st Semantic Web Authoring and Annotations Workshop at the ISWC 2006. 

We describe a generic architecture for the (semi-automatic) creation, storage and querying for annotations of web resources. Our BAsAS architecture uses recent advances from the Semantic Web and Web 2.0 communities to make Semantic Web annotations a reality. The BAsAS architecture makes it easy for users to start to annotate and easy for
developer to use the annotations that get created.

Besides describing the general architecture we will also detail an implementation of this architecture build for a Semantic Web community portal.

Think of it as Annotea but better. The presented system addresses some of the most important shortcomings of Annotea: that there are only plugins for the firefox browser (shutting out the majority of web users) and that there is no query language for annotations.

Actually I'm still quite annoyed that it only got accepted as poster. It was not "innovative enough", the changes to Annotea not big enough. Ahh well, I put it down to my bad writing. In a way I even agree that we don't need another Semantic Annotation Paper  - we need applications that come with a nice user interface and are usable "out of the box" (in particular without the need for the user to worry about finding a server - something you've to do with current Annotea tools).

The long version of the paper is here.  

Labels: publication, SemanticWeb

In this paper we describe novel ideas and their prototypical implementation for the visualization of rule bases. In the creation of the visualization our approach considers not only the structure of a rule base but also records of its usage. We also discuss the challenges for visualization algorithms posed by rule bases created with high level knowledge acquisition tools. We describe the methods we employ to deal with these challenges.

Authors are Valentin Zacharias and Imen Borgi. It was published at the SWUI workshop at the ISWC 2006. The entire paper is here.

Labels: publication

We present the conceptual basis and a prototypical implementation of a technical framework for computing syntactical and semantical similarities between instances within an ontology. The focus of this work did not only comprise the implementation of specific, ontology-based similarity measures, but also their flexible and efficient combination and extensibility.

Authors are Mark Hefke, Valentin Zacharias, Ernst Biesalski, Andreas Abecker, Qingli Wang, Marco Breiter.

Published at 8th International Conference on Enterprise Information Systems, 23 - 27, May 2006, Paphos - Cyprus

The entire paper is here.

Labels: publication

We present the architecture and the interface of a metadata registry for a large e-learning site. The metadata registry if very simple to integrate by content and application providers and thereby tries to motivate more members of the community to contribute. It takes its inspiration from currently successful semantic web architectures and aims to be an evolutionary change to the web – using long established standards where possible.

Author is just "Valentin Zacharias", published at IAWTIC 2005.

The entire paper is here.

Labels: publication

We present the architecture and interface of a metadata registry for a large e-learning site. The metadata registry is very simple to integrate by both content and application providers. It takes its inspiration from currently successful metadata architectures and aims to be an evolutionary change to the web – using long established standards where possible.

Poster at the ISWC 2005, authors are Valentin Zacharias and Stephan Grimm.

The entire paper is here.

Labels: publication, SemanticWeb

This paper stems from the idea that maybe the painstainkingly slow adoption of the Semantic Web into the mainstream www can be accelerated by taking clues from these tiny Semantic Weblets already present today.
We have identified RSS as one particularly successful Semantic Weblet, formed an opin-ion on why it was successful and have than tried to include all its success factors into a new Semantic Web application.
This paper argues that in order to build a successful Semantic Web application, considering only technical aspects is not enough; econom-ics, the motivation of the actors, necessary changes and available know how is also important.

Authors are: Valentin Zacharias and Mike Sibler

Published in the Proceedings of the Fachgruppentreffen Wissenamangement 2004.

The entire paper is here.

Labels: publication, SemanticWeb

This was actually my master project and I don't have a pdf of the paper version at hand. Not to proud of this work anyway.

Published in ASME Press Series on Intelligent Engineering Systems Through Artificial Neural Networks (ANNIE 2003), Smart Engineering System Design, eds C. Dagli et al, (2003) November, Missouri, USA

Authors:  I.Valova, N.Gueorguieva, V.Zacharias

Labels: publication

The Semantic Web will bring structure to the content of Web pages, being an extension of the current Web, in which information is given a welldefined meaning. Especially within e-commerce applications, SemanticWeb technologies in the form of ontologies and metadata are becoming increasingly prevalent and important. This paper introduce KAON - the Karlsruhe Ontology and Semantic Web Tool Suite. KAON is developed jointly within several EU-funded projects and specifically designed to provide the ontology and metadata infrastructure needed for building, using and accessing semantics-driven applications on the Web and on your desktop.

In Kurt Bauknecht and A. Min Tjoa and Gerald Quirchmayr, E-Commerce and Web Technologies, Third International Conference, EC-Web 2002, Aix-en-Provence, France, September 2-6, 2002, Proceedings, volume 2455 of Lecture Notes in Computer Science, pp. 304-313. Springer, 2002.
ISBN: 3-540-44137-9

Very long list of authors (there is actually a funny story behind one name in the authors list ... but not something to write on a website. ask me)

The entire paper is here.

Labels: publication, SemanticWeb

Text Mining is about discovering novel, interesting and usefil patterns from textual data. In this paper we discuss several means that introduce background knowledge into unsupervised text mining in order to improve the novelty, the interestingness or the usefulness of the detected patterns. Germane to the different proposals is that they strive for higher abstractions that carry more explanatory power and more possibilities for exploring the input texts that is achievable by unknowledgeable means.

Andreas Hotho, Alexander Mädche, Steffen Staab and Valentin Zacharias: Text Mining Workshop Proceedings, Springer, 2002

The entire paper is here.

Labels: publication, SemanticWeb

The Semantic Web is an extension of the current web in which information is given well-defined meaning, better enabling computers and people to work in cooperation. Recently, different applications based on this vision have been designed, e.g. in the fields of knowledge management, community web portals, e-learning, multimedia retrieval, etc. It is obvious that the complex metadata descriptions generated on the basis of pre-defined ontologies serve as perfect input data for machine learning techniques. In this paper we propose an approach for clustering ontology-based metadata. Main contributions of this paper are the definition of a set of similarity measures for comparing ontology-based metadata and an application study using these measures within a hierarchical clustering algorithm.

A. Mädche and Valentin Zacharuas, Proceedings of the Joint Conferences 13th European Conference on Machine Learning (ECML'02) and 6th European Conference on Principles and Practice of Knowledge Discovery in Databases (PKDD'02).

Entire Paper is here.

(older paper, just posted it for completeness)

Labels: publication, SemanticWeb