JOURNAL OF SCIENCES (ISLAMIC AZAD UNIVERSITY)
Year:2009 | Volume:18 | Issue:70/2 (MATHEMATICS ISSUE)|Papers Count:8

The existent methods to solve an assignment problem consider single or several crisp non-homogeneous costs. However, the real world assignments are complex and the costs are inexact. In this case, the costs are fuzzy values. In this paper, the assignment problem with several fuzzy non-homogeneous costs is introduced and a solution method based on fuzzy data envelopment analysis is suggested.

In this paper, some shortcomings of EFQM are considered. Then, using the input-output structure of EFQM and applying Data Envelopment Analysis (DEA), a method is developed to detect the nonexistence of the proportionate between the enablers and results in an organization.

Let L be a bounded lattice and ¦: G ® L be a function. We define the hyperoperation o on G for all a,b Î G as follows:a o b = {g Î G | ¦(a) Ù ¦(b) £ ¦(g)}.We prove that if G be a sublattice of L then (G,o) is a join space. Also, we prove that, if A be an abelian group, s: G ® A be a function and the image of G be a closed subset of A then (G,o) is a join space. In whicha o b = {g Î G | s(g) = s(a)s(b)}.Mathematics Subject Classification: 20N20

In this paper, we propose the numerical solution for a fuzzy nonlinear equation by fixed point method (simple iteration method). The fuzzy quantities are presented in parametric form. Some numerical illustrations are given to show the efficiency of method.

In present study, designing and fabricating a device similar to wrinkle recovery AATCC 128, and using microcontroller and computer, various torsional strains imposed to the fabric and the fabric wrinkle force was measured using a load cell.A stepper motor and screw shafts with different pitches were used to impose various strains on the fabric. Then the fabric surface changes in both direction of weft and warp were examined using image processing. Dimensional changes results in weft and warp directions were considered as (S1/S2) to represent input criteria to fuzzy model.The results of this research revealed that fabric samples with higher polyester fiber content exhibited, better wrinkle recovery and less wrinkling. According to the model of fuzzy, fabric wrinkling and deformation can be classified according to their properties and in this way the classes of fabrics can be determined.

In this paper, we introduce a new mathematical programming approach to estimate the parameters of fuzzy linear regression with crisp/fuzzy input and fuzzy output. The advantage of this approach is, both of dependent and independent variables are influenced on the objective function. Therefore, this model rectifies some problems about outliers. Also, in this paper we use possibility function in constraints. To compare the performance of the proposed approach with previous methods, three examples are presented. 

In this paper we introduce Euler method for solving one dimensional fuzzy differential inclusion. Fuzzy reachable set can be approximated by Euler method with complete analysis. The method is illustrated by numerical example.