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Knowledge-based systems consist of a knowledge base, containing information relevant to the problem, and a program to manipulate that knowledge base. The format of the knowledge—the knowledge representation—is important in making the system understandable and efficient. A key issue in many knowledge-based programs is the mechanism used to handle uncertainty. Here we outline four classes of knowledge representation and focus on the methods used to handle uncertainty.
The theory of fuzzy sets considers that everything exhibits some elasticity and is a matter of degree. When fuzzy numbers are used to evaluate the judgements of decision makers (DMs) in pairwise comparisons of alternatives following the analytic hierarchy process, the flexibility experienced by DMs has been exhibited. In order to capture this aspect of flexibility, it is important to know how to realize the flexibility degree of fuzzy numbers and further present a method of realizing its quantification. In this paper, a definition of the flexibility degree of fuzzy numbers is proposed. Some formulas are proposed to quantify the flexibility and rigidity degrees of interval numbers, triangular fuzzy numbers, and trapezoidal fuzzy numbers. A group decision making (GDM) model is developed under the consideration of the flexibility of DMs. By considering the effects of the applied scale and the reciprocal relation, the flexibility degree of interval multiplicative reciprocal comparison matrices is further defined, which is used to evaluate the flexibility degree of the DM involved in the decision process. An RD-IOWGA operator is proposed to aggregate individual interval multiplicative reciprocal matrices by associating more importance to that with less flexibility. A new algorithm is shown to solve GDM problems with interval multiplicative reciprocal preference relations. Numerical studies are carried out to illustrate the new definitions and offer some comparative analysis. The observations reveal that the developed consensus method can be used to model the GDM with a dominant position.
Fuzzy regression is one of important methods for data analysis. Fuzzy regression extends the concept of classical regression which has been constructed in the statistical framework. We show that a convex hull method can provide a powerful tool to reduce the computing time, especially for real-time data analysis. The main objective of this study is to propose an efficient real-time fuzzy regression analysis based on the use of convex hull, specifically a Beneath-Beyond algorithm. The reconstruction of convex hull edges depends on incoming vertices while a recomputing procedure can be implemented in real-time. An air pollution data is analyzed by applying the proposed approach. An important role of convex hull is emphasized in particular when dealing with the limitations of linear programming.
Holmes is a software product line tool that supports all core activities of software product line analysis and development. Holmes integrates its tools using a blackboard architecture based on a Linda tuple space. A novel feature is the use of a critiquing system to provide semantic support. This is demonstrated with an example.
This study delivers a comprehensive overview of the fundamentals of the technology of fuzzy sets, regarded as one of the essential conceptual and algorithmic settings of data mining. We review the underlying concepts of fuzzy sets and discuss their role in information granulation. The basic computing aspects of fuzzy sets are studied; these include operations on fuzzy sets, transformations of fuzzy sets, and quantification of information granularity. Our conjecture is that granularity of information plays a pivotal role in knowledge-based computing that dominates data mining pursuits. We contrast probability with fuzzy sets and underline their orthogonal character manifested in data mining.