Adrian Giurca

Handbook of Research on Emerging Rule-based Languages and Technologies: Open Solutions and Approaches

Selecting an appropriate rules-based engine requires balancing many different, and often, not well-understood properties such as business rules representation methods, rule history and life cycle management, and interoperability with external data sources. The Handbook of Research on Emerging Rule-Based Languages and Technologies: Open Solutions and Approaches provides a comprehensive collection of state-of-the-art advancements in rule languages, containing methodologies for building rule-based applications, rule interoperability and interchange, and rule-based applications. Developers of rule-based languages and technologies as well as users of these applications will find this Handbook of Research to be a significant resource within the field.

Rules on the Web: Research and Applications

We sketch a logic-based framework in which computation consists of performing actions to generate a sequence of states, with the purpose of making a set of reactive rules in the logical form antecedents → consequents all true. The antecedents of the rules are conjunctions of past or present conditions and events, and the consequents of the rules are disjunctions of conjunctions of future conditions and actions. The antecedents can be viewed as complex/composite events, and the consequents as complex/composite/macro actions or processes. States are represented by sets of atomic sentences, and can be viewed as global variables, relational databases, Herbrand models, or mental representations of the real world. Events, including actions, transform one state into another. The operational semantics maintains only a single, destructively updated current state, whereas the model-theoretic semantics treats the entire sequence of states, events and actions as a single model. The model-theoretic semantics can be viewed as the problem of generating a model that makes all the reactive rules true.

Using rules and R2ML for modeling negotiation mechanisms in e-commerce agent systems

With the spread of e-commerce on a global scale, the development of truly open semantic descriptions of negotiation mechanisms for agent systems generated a lot of interest in the research community. This paper proposes the use of the REWERSE rule-markup language R2ML for semantic modeling of negotiation mechanisms to enable agents to engage in more flexible and open negotiations. Rules are developed on top of an ontology of negotiation concepts and define a lingua franca for all software agents participating in negotiation.

Towards Sharing Rules Between OWL/SWRL and UML/OCL

The paper presents a metamodel-driven model transformation approach to interchanging rules between the Semantic Web Rule Language along with the Web Ontology Language (OWL/SWRL) and Object Constraint Language (OCL) along with UML (UML/OCL). The solution is based on the REWERSE Rule Markup Language (R2ML), a MOF-defined general rule language, as a pivotal metamodel and the bidirectional transformations between OWL/SWRL and R2ML and between UML/OCL and R2ML. Besides describing mapping rules between three rule languages, the paper proposes the implementation by using ATLAS Transformation language (ATL) and describes the whole transformation process involving several MOF-based metamodels, XML schemas, EBNF grammars.

Sharing OCL Constraints by Using Web Rules

This paper presents an MDE-based approach to interchanging rules between the Object Constraint Language (OCL) and REWERSE I1 Rule Markup Language (R2ML). The R2ML tends to be a standard rule markup language by following up the W3C initiative for Rule Interchange Format (RIF). The main benefit of this approach is that the transformations between languages are completely based on the languages’ abstract syntax (i.e., metamodels) and in this way we keep the focus on the language concepts rather than on technical issues caused by different concrete syntax. In the current implementation, we have supported translation of the OCL invariants into the R2ML integrity rules. While most of the OCL expression could be represented in the R2ML and other rule languages, we have also identified that collection operators could only be partially supported in other rule languages (e.g., SWRL).

Using UML-based Rules for Web Services Modeling

In this paper, we present a UML- and rule-based approach to modeling Web services. The core of the solution is the UML-based rule model language (URML) that allows for developing business vocabularies and rules independent of an implementation technology. This helps developers to focus on solving problems under study rather than on low-level platform-specific details. Here we demonstrate how several Web service message exchange patterns can be modeled by URML. To support the use of the proposed solution we: extend a well-known UML tool Fujaba, employ the REWERSE rule markup language (R2ML) for encoding rules, and provide transformations between R2ML and WSDL, and thus round-trip engineering of Web services.

Towards a BPMN Semantics Using UML Models

Standardization initiatives on the field claim to be a consequence of the long expected maturity of Business Process Management (i.e. BPM) market and they try to impose a precise semantics for an unique and common understanding. Standard specifications provide usually less or more informal description of the involved languages. Open-source/proprietary tools often do not succeed to generate an executable code by following only the specifications requirements. Therefore, they could not make a clear distinction between the specification technology they implement, and their own requirements vis-a-vis the enactment. For the sake of a common understanding of the concepts, and for future improvements of the languages, a high-level modelling using UML is needed. The aim of the paper is to discuss Service Interaction Patterns directly supported by BPMN 1.1, and to use UML models in order to describe the abstract syntax of the involved concepts. An informal correspondence with WS-BPEL 2.0 elements is provided, together with their associated UML models description. As a consequence of the limited support for Service Interaction Patterns, another purpose of the paper is to discuss the directions in which the BPMN Standard seems to evolve, in order to suit the industry demands.

Semantic Web and Rule Reasoning inside of E-Learning Systems

This paper describes how the Semantic Web and the JenaRules can work together in order to empower e-Learning platform Moodle with rich reports and flexible courses management. We discuss aspects of using Semantic Web technologies in e-learning in general and the JenaRules in particular. The main focus is towards using rules for reasoning on top of existing Moodle content.

Approximate Reasoning Using Fodor's Implication

Using generalized modus ponens reasoning, we examine the values of the inferred conclusion using the Fodor’s implication in order to interpret a fuzzy if-then rule with a single input single output and the T-norms t1(x, y) = min(x, y), t2(x, y) = xy and t3(x, y) = max(0, x + y − 1) for composition operation. These are the very used T-norms in generalized modus ponens reasoning.

Rule Modeling and Interchange

This paper is a brief survey on the topic of rule modeling and rule interoperability. A framework focusing on the first two levels of the MDA (that is, on business/domain models and on logical design models) is described. Rules are modeled either in natural language (ACE) or by means of a visual language (VRML). The interoperability layer is performed by R2ML an XML markup for rules. OMG has defined a markup language for UML models but this language does not markup embedded integrity constraints expressed in OCL. VRML is designed to cover this lack of representation. R2ML follows principles initiated in RuleML but, despite RuleML, it performs the on- tological distinction between objects and data values. Also, by its rich syntax, 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 EC A rule into a production rule, a function into a predicate, or a typed atom into an untyped atom.