The mission of the working group "rule modeling and markup" is to facilitate the use of rule formalisms and technologies for inference-enabled Web applications by developing an integrated modeling, visualization, verbalization and markup framework that is supported by tools.


The REWERSE Working Group I1 on Rule Markup Languages has completed its work in February 2008. Its objectives are summarized in the following statement:
Facilitate the use of rule formalisms and technologies for inference-enabled Web applications by developing an integrated rule modelling, visualization, verbalization and markup framework that is supported by tools.

Work performed towards objectives

The work performed towards the objectives of WG I1 has focused on rule modelling and rule markup, but it has also been concerned with rule visualization and rule verbalization. In addition, WG I1 has adopted the objective to develop a Web rule formalism based on RDF.

In the area of rule markup and rule interchange, a markup language for different kinds of rules (R2ML) has been defined in the form of a MOF/UML model and an XML schema, and a set of experimental translators for rule interchange have been developed and deployed on the Web.

In the area of rule modelling, a UML-based rule modelling language (URML) has been defined (in the form of a MOF/UML model) and implemented in the graphical rule modelling tool Strelka, which allows to capture rules in the semi-graphical syntax of URML and to serialize the URML rule expressions in the R2ML format with the option to generate specific rule code from the R2ML representation for one of the target platforms Jena Rules, JBoss Rules and FLogic.

Concerning the objective to develop a Web rule formalism based on RDF, WG I1 has developed Extended RDF (ERDF) by extending the triple and XML syntax of RDF, and by conservatively extending its model-theoretic semantics on the basis of partial logic. Unlike RDF and OWL, ERDF supports two kinds of negation, open and closed predicates, as well as default rules for expressing heuristics. A prototype implementation of ERDF has been built on top of the Jena Semantic Web framework.

End results/durable impact

The main results are

Main Results: Reasoning Languages and Advanced Web Applications

Main results: Use-case suites, datasets, user studies

A rule-based implementation of the UServ use case for computing the fee of vehicle insurance policies using URML and R2ML

Main results: Publication/exploitation of demonstrators and prototypes

The group has published its demonstrators and prototypes on the project Web site:

Information Systems: Vocabularies, Ontologies and Rules for Enterprise and Business Process Modeling and Management

This special issue solicits papers focused on the following described research areas.

Strelka 0.3: UML-based rule modeling tool for Eclipse with rule code generation

The new Strelka version 0.3 for Eclipse is now available for download.

New features

  • Strelka 0.3 runs under the Eclipse Framework, which provides a user-friendly interface and a better performance.
  • The proven MDT OCL parser is used.
  • Integration with rule code generation services via the rule exchange format R2ML: just right-click on a rule circle and select the target rule language.

ACE to R2ML Translator

The first (demo) version of the ACE to R2ML translator is available. The translator allows any correct ACE sentence as an input and generates the corresponding R2ML integrity rule. The translator has some restrictions and does not support the full syntax of ACE.

UServ Use case implemented with Take

Jens Dietrich implemented the UServ Product Derby 2005 by using Take rule compiler. It is a JavaWebStart application. Read more.

Extending the Resource Description Framework (RDF) by Adding Negation and Rules

The REWERSE I1 Rules Framework

The REWERSE I1 Rules Framework is a comprehensive system involving languages and tools with two main goals: Visual Modeling of Rules and rule deployment into different execution platforms and Rule Interchange between different rules systems and tools.

R2ML -- The REWERSE I1 Rule Markup Language

R2ML is a comprehensive and user-friendly XML rule format that allows

  • interchanging rules between different systems and tools,
  • enriching ontologies by rules,
  • connecting your rule system with (our) R2ML-based tools for visualization, verbalization, verification and validation.

R2ML is comprehensive in the sense that it integrates

the Object Constraint Language (OCL)
a standard used in information systems engineering and software engineering,
the Semantic Web Rule Language (SWRL)
a proposal to extend the Semantic Web ontology language OWL by adding implication axioms,
the Rule Markup Language (RuleML)
a proposal based on Datalog/Prolog,

and it includes four rule categories: derivation rules, production rules, integrity rules and ECA/reaction rules.

"For enriching ontologies with rules, use R2ML rather than SWRL because it's more powerful." [Gerd Wagner, co-ordinator of the Rule Modeling and Markup research project REWERSE I1]

R2ML is a usable language in the sense that it allows structure-preserving markup and does not force users to translate their rule expressions into a different language paradigm such as having to transform a derivation rule into a FOL axiom, an ECA rule into a production rule, a function into a predicate, or a typed atom into an untyped atom.

Strelka -- An URML-Based Visual Rule Modeling Tool

The languages used in the communication between system analysts and domain experts for analyzing and documenting system requirements should not be ’technical’, but should allow visual and/or natural-language-like vocabulary and rule expressions that can be understood by domain experts without extensive technical training.