Journal of Intelligent & Fuzzy Systems - Volume 21, issue 4

Authors: Wang, S. | Watada, J.

Article Type: Research Article

Abstract: The objective of this paper is to derive some limit theorems of fuzzy random variables under the extension principle associated with continuous Archimedean triangular norms (t-norms). First of all, some convergence theorems for the sum of fuzzy random variables in chance measure and expected value are proved respectively based on the arithmetics of continuous Archimedean triangular norms. Then, a law of large numbers for fuzzy random variables is established by using the obtained convergence theorems. The results of the derived law of large numbers can degenerate to the strong laws of large numbers for random variables and fuzzy variables, respectively.

Keywords: Limit theorem, Law of large numbers, Fuzzy random variable, Archimedean t-norm

DOI: 10.3233/IFS-2010-0446

Citation: Journal of Intelligent & Fuzzy Systems, vol. 21, no. 4, pp. 233-242, 2010

Authors: Bilgen, Bilge

Article Type: Research Article

Abstract: This paper addresses a supply chain network planning problem faced by a company that manages a golf club supply chain. The supply chain network is considered for the production of several products through an assembly of three modules supplied by different suppliers. A linear programming model is proposed to describe the problem, where multiple components can be assembled within a planning horizon of one to twelve months. The model involves the supply of various components from a set of suppliers and allocation of assembled products to customers. In real world problems practical situations are often not well-defined and thus can …not be described precisely. Therefore this model is transformed into the fuzzy models with flexibility in the objective function, in the market demand, and in the available capacity of resources. The main objective is to construct a procurement-assembly plan enabling it to minimize its costs while satisfying the customers’ demand over a given planning horizon in such a way as to hedge against uncertainty. Finally, the proposed model is tested using a case of supply chain from the golf club industry. Sensitivity analyses are also conducted on various parameters to gain insight into the proposed model. Numerical case demonstrates that the proposed fuzzy model can provide a better and more flexible way of representing the problem for the considered industry. Show more

Keywords: Supply chain management, fuzzy mathematical programming, supply chain modeling and optimization

DOI: 10.3233/IFS-2010-0454

Citation: Journal of Intelligent & Fuzzy Systems, vol. 21, no. 4, pp. 243-253, 2010

Authors: Cristea, Irina | Darafsheh, Mohammad Reza

Article Type: Research Article

Abstract: The study of fuzzy subhypergroups of the complete hypergroups is an important area of research in fuzzy structure theory. Since this structure relies on a certain decomposition of a group G,in this paper we consider the cyclic groups of orders p and p2 and prove that they have the required decomposition. Here we use some aspects of group theory to solve a problem in the fuzzy algebraic hyperstructure theory.

Keywords: Groups, fuzzy subhypergroups, complete hypergroups

DOI: 10.3233/IFS-2010-0455

Citation: Journal of Intelligent & Fuzzy Systems, vol. 21, no. 4, pp. 255-259, 2010

Authors: Touzi, Amel Grissa | Hassine, Mohamed Ali Ben

Article Type: Research Article

Abstract: Several applications need to stock and interrogate fuzzy data in a flexible manner. Unfortunately, these two requirements are not supported by the database management systems which currently dominate the databases servers market. Several works have tried to cure these insufficiencies; we speak henceforth of fuzzy databases and flexible querying of these databases. The design problem of such databases did not receive the interest that it deserves. The fuzzy data types are numerous and varied what puts the designer of a fuzzy database in front of a complex problem of choice. In this paper, we propose an approach based on an …expert system which helps the designer to choose the appropriate data types for the columns susceptible to stock fuzzy data or interrogated by flexible queries. This solution suits the migration toward a fuzzy database as well as a fuzzy database under design. Although this solution is based on the fuzzy model GEFRED (GEneralised model for Fuzzy RElational Database), it can be applied to other fuzzy models. This expert system can be integrated into the classic design environments like Rational Rose, Power AMC, etc. Show more

Keywords: Fuzzy Databases, Expert Systems, Fuzzy Attributes, FSQL, GEFRED

DOI: 10.3233/IFS-2010-0456

Citation: Journal of Intelligent & Fuzzy Systems, vol. 21, no. 4, pp. 261-273, 2010