Tutorial on Semantic Modelling (Feb 25th)

Posted in OWL, Ontology, Presentation, RDF, SKOS, artificial intelligence on February 23rd, 2010 by Rinke HoekstraBe the first to comment

I have given (part of) a tutorial on semantic modelling for the XMLHolland community on February 25th. Course material about my part (about Semantic Web technology) is available online at:

http://www.few.vu.nl/~hoekstra/semantic-modelling-2010.zip

My presentation is available on SlideShare, and embedded below:

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TimBL on the Next Web (TED February 2009)

Posted in OWL, RDF on February 9th, 2010 by Rinke HoekstraBe the first to comment

Twitter Weekly Updates for 2010-02-07

Posted in Uncategorized on February 7th, 2010 by Rinke HoekstraBe the first to comment

(Famous) first lines of Jurix 2009

Posted in Quotes on January 4th, 2010 by Rinke HoekstraBe the first to comment

Search in semi-structured documents has received the interest of researchers for several decades. The automated validation of XML documents is of fundamental importance when dealing with large collections of legal documents. Laws tend to be drafted in abstract terms intended to express the legislative will in a way which covers the widest possible range of situations. Normative systems are “systems in the behavior of which norms play a role and which need normative concepts in order to be described or specified”. MetaLex has been confirmed as a CEN/ISSS publicly available specification (CWA15710) in 2006, and is in the process of being updated in late 2009 by the MetaLex CEN/ISSS workshop on an Open XML Interchange Format for Legal and Legislative Resources. In the domains of accounting and law there is a long standing debate about the relative merits of rule-based versus principle-based regulatory systems. New and emerging technologies have led to new ways of doing business.

The complexity and quantity of legislation and regulations in both governmental and business operations are increasing at an alarming rate. Knowledge modelling represents a structural pre-condition for implementing the Semantic Web concept as well as intelligent systems dealing with legal information. The need to share and improve access to government data is currently acknowledged around the globe. Fuel fraud is a prevailing crime of the black market in Poland and some other countries, e.g. UK (where it is costing UK taxpayers 350 mln up to a billion pounds a year). Recently there has been a growing interest in the development of intelligent systems to support evidential legal and forensic reasoning. This paper presents an ontology based model developed with regard to the transposition of the EU Directive on Services 2006/123/EC in Austria.

Diagrammatic models of argument are a growing area of research in AI and Law. At the Leibniz Center for Law, we have developed an editor for legislative drafters with which they can create laws in CEN/MetaLex XML format: MetaVex. This paper explores a novel approach to study legal interactions by means of agent-based simulation. In recent years, there has been a growing interest in improving the accessibility of legislation. There are many national and international XML standards for modelling and representing legal resources, and when it comes to modelling norms by way of rules, we also find a worldwide array of standards (such as RIF, SBVR, RuleML). Managing the information represented in large collections of documents is a big problem for public administrations: the size of documental archives grows continuously while peculiarities of the legal domain imposes searches which may span across decades and a plethora of information sources.

The Japanese Presupposed Ultimate Fact Theory (called “Yoken-jijitsu-ron” in Japanese), which we will call the JUF theory in this paper, has been mainly developed by judges in the Japanese Legal Training Institute in order to handle the uncertainty that sometimes occur in the court because of a lack of enough evidence. This paper describes a system for generating artificial law cases for students to solve autonomously in an E-Learning setting. More and more people on the working floor are expected to have knowledge of the sources of law that are applicable to their field.

jurix2009-wordle

(from Jurix 2009 proceedings)

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Cherry-picking Jurix 2009 papers

Posted in OWL, Ontology, What other people think, artificial intelligence on January 4th, 2010 by Rinke HoekstraBe the first to comment

Just a first batch of cherries from the Jurix 2009 paper cake (online versions here):

Emerald: Legal Knowledge Engineering using OWL and Rules
András Förhécz, Gábor Kőrösi, András Millinghoffer and György Strausz

Emerald is a knowledge engineering environment developed by the people at the Budapest University of Technology and Economics together with Multilogic. The system is an extensive redesign of the Allex Gold system, which performed backward-chaining on Prolog like rules. Emerald is based on the OWL 2 language, and adds expressiveness in the form of aggregate functions (translatable to DL queries), and reasoning with incomplete knowledge (i.e. a local closed-world interpretation of property values). The system also uses a simple rule language to specify the flow of user interaction: rules indicate what property values must be filled before a class restriction is satisfied.

I think it’s unfortunate that this work was only accepted as a short paper, since this work may turn out to become very influential in enterprise-class legal assessment systems (e.g. it is a big step from the propositional calculus of ORACLE’s Haley Office Rules to OWL 2 DL). On the other hand, this work should really be presented at a venue such as OWLED or the KR workshop series as the system is essentially domain independent. From a more legal perspective, the system is described at a too technical level, leaving many issues unmentioned that are particular to (normative) legal knowledge, such as exceptions. Also, I feel the Hungarian language should drop some of its accents.

MetaLex Naming Conventions and the Semantic Web
Alexander Boer

As an XML standard for legal sources (laws, court proceedings etc.) MetaLex has been around for some time now (developed by the University of Amsterdam in 2001), but the relatively new CEN MetaLex brings a significant overhaul of the original design. The new mechanism for specifying naming conventions is but one aspect of this.  MetaLex names are used in self-identification of documents, citation of other documents, and inclusion of document components according to the FRBR levels of item, manifestation, expression and work. A naming mechanism is important for interchange between systems because local implementations may depend on different ways to combine property-value pairs in constructing the IRI’s used to uniquely identify bibliographic entities. In other words, insight in the way in which IRI’s are constructed helps in the discovery of owl:sameAs relations between entities. Arguably, this is a topic very much of interest to the linked open data community (e.g. considering the submissions to the Web of Data track at ESWC 2010, and European projects such as OKKAM).

This paper introduces the naming mechanism (which is quite intricate), and describes how the uniqueness of IRIs can be guaranteed by using a GRDDL transform for translating the property-value pairs encoded in the IRI to OWL class axioms (using nominals, and proper relations between the different FRBR levels). A DL classifier can then infer owl:sameAs relations between entities (individuals) described using the appropriate property value pairs.

Again, given the issues at hand in linked open data, this approach has potential well beyond the AI and Law community.

Rule-based versus Principle-based Regulatory Compliance
Brigitte Burgemeestre, Joris Hulstijn and Yao-Hua Tan

The paper discusses the problems surrounding regulatory compliance, and the influence of different legal systems in specifying regulations on the type of legal reasoning required for systems. The authors focus on rule-based versus principle-based regulations, and identify seven dimensions along which the two approaches differ:

  • temporal (ex ante vs. ex post),
  • conceptual (specific vs. general),
  • functional (little vs. large discretionary power),
  • representation (procedural vs. declarative),
  • background knowledge needed (little vs. a lot),
  • exception handling (strict vs. defeasible),
  • conflict resolution (no conflicts possible vs. tradeoff between weights)

They study these dimensions in the context of European (AEO) and US customs regulations (C-TPAT). It turns out that although AEO is mostly principle-based, and C-TPAT is mostly rule-based, both can indeed be positioned at a continuum on which strictly rule- or principle-based regimes form the extremes (as argued earlier by Cunningham and Sadiq et al.). The paper represents a case using Reason Based Logic (Verheij et al.) which illustrates the difficulty in deciding what to represent as a principle, and what to represent as a rule.

I think it is a good thing that the distinction between the two regimes is again brought to the attention of the AI and Law community (especially by authors not especially active in the field): it emphasises the bigger picture of one of the real challenges in AI and Law, namely the development of technology that can be broadly applied, rather than only to interesting, but highly specific problems.

… that’s it for now, more to come (I hope)

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BestMap

Posted in BEST project, OWL, Ontology, SKOS, mapping on December 22nd, 2009 by Rinke HoekstraBe the first to comment

Just created a page that explains some of the benefits of the BestMap ontology approach to vocabulary mapping. Its most important feature is the ability to specify many-to-many mappings between concepts in two or more SKOS vocabularies, in a way that does not interfere with the semantics of standard SKOS relations.

BestMap is defined in OWL 2 and was developed as part of my work on the BestPortal, a portal that is intended to help citizens to determine whether their case has a chance in court (developed within the BEST project).

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One year hence

Posted in BEST project, Life, OWL, Ontology, artificial intelligence, dissertation on December 15th, 2009 by Rinke HoekstraBe the first to comment
175 px
Image via Wikipedia

Just realised that the last post on this blog dated December 2008… a lot has happened since then. For one, I became the father of Lieve.

Less importantly, I submitted the manuscript of my dissertation just before Christmas… luckily it was accepted, and I became a ‘doctor’ on the 18th of September this year (took a while because of planning issues…).

My dissertation was published by IOS Press and has the title “Ontology Representation – Design Patterns and Ontologies that Make Sense“. It really turned into a proper book, with (I think) several good introductory chapters on (the history of) knowledge representation, the requirements imposed on knowledge representation languages and on ontologies. I have tried to demystify several assumptions underlying ontology engineering related to methodologies and reusability, and describe a structured approach to ontology representation (that is, the construction of ontologies used as knowledge representation artefacts). This approach has brought forth several quite elaborate design patterns that make extensive use of the new OWL 2 constructs (such as role chains, self restrictions and qualified cardinality).

The book is available from Amazon, and other online outlets, but can also be browsed in digital form through the DARE repository of the University of Amsterdam.

Another fairly big change is that since the first of March, I am ‘on loan’ to the AI department of the Vrije Universiteit, to work on the BEST project. I am very lucky to be able to spend my weekdays at one of the foremost research departments on knowledge representation and the Semantic Web.

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Blog Back

Posted in Life on December 14th, 2009 by hoekstraBe the first to comment

I just reinstated my blog thing, which was lost during the previous backup-reinstallation-nightmare-event. So, at least my older posts will be found again by Google, and I will have a slightly more eloquent way to share some ideas than just the 140 character blurts of Twitter (RinkeHoekstra)

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W3C Publishes OWL 2 “last call” drafts

Posted in OWL, Ontology, RDF on December 5th, 2008 by Rinke HoekstraBe the first to comment

The W3C OWL Working Group has just published a set of eleven documents for public review.  These documents cover “OWL 2“, which is now fairly stable.  This is a good time to review this work and send us comments (at public-owl-comments@w3.org).  Comments received by 23 January will be answered and taken into account in the next round of publications. The group expects to issue the OWL 2 Candidatate Recommendations, with a call for implementations, shortly after that comment deadline.

The documents are:

1. Structural Specification and Functional-Style Syntax
http://www.w3.org/TR/2008/WD-owl2-syntax-20081202/
2. Direct Semantics
http://www.w3.org/TR/2008/WD-owl2-semantics-20081202/
3. RDF-Based Semantics
http://www.w3.org/TR/2008/WD-owl2-rdf-based-semantics-20081202/
4. Conformance and Test Cases
http://www.w3.org/TR/2008/WD-owl2-test-20081202/
5. Mapping to RDF Graphs
http://www.w3.org/TR/2008/WD-owl2-mapping-to-rdf-20081202/
6. XML Serialization
http://www.w3.org/TR/2008/WD-owl2-xml-serialization-20081202/
7. Profiles
http://www.w3.org/TR/2008/WD-owl2-profiles-20081202/
8. Quick Reference Guide
http://www.w3.org/TR/2008/WD-owl2-quick-reference-20081202/
9. New Features and Rationale
http://www.w3.org/TR/2008/WD-owl2-new-features-20081202/
10. Manchester Syntax
http://www.w3.org/TR/2008/WD-owl2-manchester-syntax-20081202/
11. rdf:text: A Datatype for Internationalized Text
http://www.w3.org/TR/2008/WD-rdf-text-20081202/

Of these eleven documents:

* The first seven are the core technical specification for OWL 2.
Six of these now at “Last Call”.  This means the Working Group
believes the design is done and that the only changes going
forward will be editorial, along with certain items highlighted
as “at risk” in the documents.  The other one, “RDF-Based
Semantics” (which specifies OWL 2 Full) is expected to proceed
to Last Call shortly.

* The “Quick Reference Guide” and “New Features and Rationale” will
be a good place to start for many OWL users, these documents will
be a good place to start.  (A Primer is also being developed, and
a earlier draft was published, but it has not yet been updated to
account for the current state of the language.)

* “Manchester Syntax” specifies an alternative syntax for OWL
which some users prefer and some tools implement, but which is
not required.

* “rdf:text” specifies an XML datatype (developed jointly with
the RIF Working Group) which provides a way to deal with RDF
language-tagged literal strings without making them be a
special case.

Again, please send comments to public-owl-comments@w3.org by 23 January.
Discussion on either of these lists is fine, but might not be seen by the Working Group.

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EKAW 2008: Polishing Diamonds in OWL 2

Posted in OWL, Ontology, Presentation on October 10th, 2008 by Rinke HoekstraBe the first to comment

Last week I gave a presentation at the EKAW 2008 conference on the paper I wrote together with Joost Breuker entitled Polishing Diamonds in OWL 2:

Rinke Hoekstra and Joost Breuker. Polishing diamonds in OWL2. In Aldo Gangemi and Jérôme Euzenat, editors, Proceedings of the 16th International Conference on Knowledge Engineering and Knowledge Management (EKAW 2008), LNAI/LNCS. Springer Verlag, October 2008.

Unfortunately I cannot publish the paper itself here (though it is available from the Springer LNAI website under the DOI: http://dx.doi.org/10.1007/978-3-540-87696-0_8 ). The presentation can be downloaded at Polishing Diamonds in OWL 2 (EKAW 2008).

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