One of the foci of the recent developments in object-oriented modeling Ε½ . OOM has been the extension of fuzzy logic to OOM to handle information that is imprecise in nature. Fuzzy theory, as a modeling mechanism, is especially useful in tackling real world applications whose complexity demands are growing intensively. In this volume, we are featuring five papers devoted to integration of fuzzy logic and object-oriented technology as a special issue.
J. Lee, J. Y. Kuo, and N. L. Xue have attempted a survey of current approaches carried out in the confluence of the two technologies, fuzzy set theory and object-oriented technology, that could provide a powerful tool for enhancing database management systems, software modeling, and knowledge representation in AI systems.
G. Bordogna and G. Pasi advocate a set of graph-based operations to browse and retrieve information from a graph-based fuzzy object-oriented data model. For the aim of retrieving data on the basis of selection conditions, both crisp and soft constraints on data can be specified either on attribute values or on objects relations.
V. Cross examines various semantics of uncertainty and the interaction with three kinds of relationships inherent to object models: instance-of, a-kind-of, and a category. A generalized object model is the basis for the recommendation for fuzzy extensions to these three kinds of relationships.
N. Marin, O. Pons, and M. A. Vila offer a new perspective for representing the fuzzy type associated to a class, tackling the problem of vagueness in the database schema and defining the concept of fuzzy type. They have defined a fuzzy type as a pair with structural and behavioral components.
A. Yazici, Q. Zhu, and N. Sun introduce a semantic data modeling approach for spatiotemporal database application. This approach extends UML Ε½ . unified modeling language for handling spatiotemporal information, uncertainty, and fuzziness especially at the conceptual level of database design.
We express our sincere gratitude to everyone who has contributed to this special issue including the authors, the reviewers, and the IJIS Editor-in-Chief Professor Ronald Yager.