• Proceedings of the KIEE Conference
• /
• 1993.07a
• /
• pp.489-491
• /
• 1993

Many optimization problem or multiple attribute, multiple alternative decision making problem may have fuzzy evaluation factors. In this case, fuzzy number operation technique is needed to evaluate and compare object functions which become fuzzy sets. Generally, fuzzy number operations can be defined by extension principle of fuzzy set theory, but it is tedious to do fuzzy number operations by using extension principle when the membership functions are defined by complex functions. Many fast methods which approximate the membership functions such as triangle, trapezoidal, or L-R type functions are proposed. In this paper, a fast fuzzy number operation method is proposed which do not simplify the membership functions of fuzzy numbers.

• Communications for Statistical Applications and Methods
• /
• v.15 no.4
• /
• pp.517-530
• /
• 2008

In this paper we introduce a time series model using the triangle fuzzy numbers in order to construct a statistical relation for the data which is a sequence of observations which are ordered in time. To estimate the proposed fuzzy model we split of a universal set includes all observation into closed intervals and determine a number and length of the closed interval by the frequency of events belong to the interval. Also we forecast the data by using a difference between observations when the fuzzified numbers equal at successive times. To investigate the efficiency of the proposed model we compare the ordinal and the fuzzy time series model using examples.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.27 no.4
• /
• pp.94-104
• /
• 2004

This paper proposed a new method to evaluate service quality attribute of perceived service quality in public sectors, using triangle fuzzy numbers and hamming distance. Our method measured the ratio of the expected and perceived service for the customers' perceived service quality. By using fuzzy numbers, This method not only overcomes linguistic variable problems but also provides more objective and direct information for service quality attributes. The discrepancy rate between expected service and perceived service that is perceived service quality is evaluated by hamming distance. To evaluate the discrepancy rate from hamming distance, we induced general solutions to compute the intersection area between two triangle fuzzy numbers and the weak or strong attributes in public sectors are clarified.

• Journal of Korean Society for Quality Management
• /
• v.32 no.3
• /
• pp.182-197
• /
• 2004

In this paper we propose a new method of evaluating customers' service quality using triangle fuzzy numbers and semantic differential scale. These two parameters are useful for quantifying the customers' linguistic variables and subjective judgements. We define the Service Quality(SQ) as the ratio of the expected and perceived service and address the Agreement Rate(AR) calculated from the hamming distance in order to define the Service Rate(SR) as the geometric mean of the SQ and AR. Using the SR in the analysis of service attributes provides more appropriate to measure the customers' service quality and to establish a creative service policy for competitive service quality improvement.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 1993.06a
• /
• pp.1191-1194
• /
• 1993

We consider a fuzzy controller corresponding to PI controller. This controller is applied to a controlled object which is a first order lag system with dead time. An antecedent part is divided into 3, 5, and 7 parts ( membership function of triangle shape ), and a consequent part into 3, 5, and 7 parts ( membership function of singleton ). In each combination of an antecedent part and a consequent one. We compare control efficiency under the performance criteria such that the overshoot is kept 20% and the ITAE index is minimized.

• Proceedings of the KIEE Conference
• /
• 2004.11c
• /
• pp.337-339
• /
• 2004

In this paper, we discuss optimal design of Fuzzy Polynomial Neural Networks by means of Genetic Algorithms(GAs). Proceeding the layer, this model creates the optimal network architecture through the selection and the elimination of nodes by itself. So, there is characteristic of flexibility. We use a triangle and a Gaussian-like membership function in premise part of rules and design the consequent structure by constant and regression polynomial (linear, quadratic and modified quadratic) function between input and output variables. GAs is applied to improve the performance with optimal input variables and number of input variables and order. To evaluate the performance of the GAs-based FPNNs, the models are experimented with the use of Medical Imaging System(MIS) data.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.27 no.3
• /
• pp.66-74
• /
• 2004

In this paper the authors presents a new method, named FR-SERVQUAL, of evaluating perceived service quality in Public Sectors, using triangle fuzzy numbers and semantic differential scale. By conventional quantification methods, it is not easy to express the notion of a linguistic variables and customers' subjective judgements. In contrast to the conventional PZB methods which express the customers' perception of quality as a function of gap between the expected and perceived service, this paper suggests to use the ratio of the two. Through an application example, this paper shows that the current FR-SERVQUAL approach provides a more realistic way of measuring service quality compared to existing methods.