Fundamenta Informaticae - Volume 82, issue 3

Article Type: Other

Citation: Fundamenta Informaticae, vol. 82, no. 3, pp. i-i, 2008

Authors: de Bruijn, Jos | Heymans, Stijn

Article Type: Research Article

Abstract: Many popular ontology languages are based on (subsets of) first-order predicate logic, with classes represented by unary predicates and properties by binary predicates. Specifically, the SemanticWeb ontology language OWL DL is based on the Description Logic SHOIN. F-Logic is an ontology language which is also based on first-order logic, but classes and properties are modeled as terms rather than predicates. Our goal is to enable interoperation between predicate-based and F-Logic-based ontology languages. To …this end, we define an intuitive translation from predicate-based ontologies to F-Logic ontologies and show that this translation preserves entailment for large classes of ontology languages, including most of OWL DL. Specifically, we define the class of equality-safe (E-safe) formulas, show that the Description Logic SHIQ is E-safe, and show that the translation preserves validity of E-safe formulas. We use these results to close the open problem of layering F-Logic programming on top of Description Logic Programs and we show that our results apply to HILOG, a syntactically higher-order, but semantically first-order language. Finally, we show that our results also apply to a meta-modeling extension for Description Logics (v-semantics). Show more

Keywords: frame logic, ontology translation, ontology meta-modeling, equality-safe formulas, semantic web language layering, f-logic programming

Citation: Fundamenta Informaticae, vol. 82, no. 3, pp. 213-236, 2008

Authors: Behrends, Erik | Fritzen, Oliver | May, Wolfgang | Schenk, Franz

Article Type: Research Article

Abstract: We describe how Event-Condition-Action (ECA) rules can be combined with event algebras like SNOOP for specification of the event part, and process algebras like CCS for specification of the action part to obtain a powerful, declarative formalism that also covers intuitively procedural tasks in an appropriate way. Since these formalisms have a concise formal semantics, verification and other kinds of reasoning about such specifications are possible. Using a rulemarkupwith cleanly distinguished rule components allows …for such a compositional approach. The approach is currently under implementation in the MARS (Modular Active Rules for the Semantic Web) Framework. Show more

Citation: Fundamenta Informaticae, vol. 82, no. 3, pp. 237-263, 2008

Authors: Damásio, Carlos Viegas | Pan, Jeff Z. | Stoilos, Giorgos | Straccia, Umberto

Article Type: Research Article

Abstract: The RuleML initiative defines a normalized markup for expressing and exchange rules in the Semantic Web. However, the syntax of the language is still limited and lacks features for representing rule-based languages capable of handling uncertainty and vagueness. It is desirable to have a general extension of RuleML which accommodates major existing languages proposed in the latest two decades. The main contribution of the paper is to propose such a general extension, showing how to encode …many of the existing languages in this extension. It is detailed the important case of fuzzy rule languages. We hope this work can also provide some insights on how to cover uncertainty in the RIF framework. Show more

Citation: Fundamenta Informaticae, vol. 82, no. 3, pp. 265-288, 2008

Authors: Lukasiewicz, Thomas

Article Type: Research Article

Abstract: There are numerous semantic web applications where dealing with vagueness and imprecision plays an important role. Some examples of such applications are (i) multimedia information processing and retrieval, (ii) natural language interfaces to the Web, and (iii) ontology mapping and information retrieval. In this paper, towards dealing with vagueness and imprecision in the reasoning layers of the Semantic Web, we present an approach to normal fuzzy description logic programs under the answer set semantics, …which are a generalization of normal description logic programs (dl-programs) under the answer set semantics by fuzzy vagueness and imprecision in both the description logic and the logic program component. We define a canonical semantics of positive and stratified fuzzy dl-programs in terms of a unique least model and iterative least models, respectively. We then define the answer set semantics of general fuzzy dl-programs, and show in particular that all answer sets of a fuzzy dl-program are minimal models, and that the answer set semantics of positive and stratified fuzzy dl-programs coincides with their canonical least model and iterative least model semantics, respectively. We also provide a characterization of the canonical semantics of positive and stratified fuzzy dl-programs in terms of a fixpoint and an iterative fixpoint semantics, respectively. Furthermore, we provide a reduction of fuzzy dl-programs under the answer set semantics to normal dl-programs under the answer set semantics. Finally, we also describe a special case of fuzzy dl-programs where query processing can be done in polynomial time in the data complexity. Show more

Keywords: Fuzzy description logic programs, fuzzy description logics, fuzzy normal programs, answer set semantics, vagueness and imprecision, Semantic Web

Citation: Fundamenta Informaticae, vol. 82, no. 3, pp. 289-310, 2008