• Structural Engineering and Mechanics
• /
• v.76 no.6
• /
• pp.781-797
• /
• 2020

In recent years, there is an increasing interest to optimize the fuzzy logic controller with different methods. This paper focuses on the optimization of a fuzzy logic controller applied to a seismically excited nonlinear building. In most cases, this problem is formulated based on the linear behavior of the structure, however in this paper, four sets of objective functions are considered with respect to the nonlinear responses of the structure as the peak interstory drift ratio, the peak level acceleration, the ductility factor and the maximum control force. The Improved Charged System Search is used to optimize the membership functions and the rule base of the fuzzy controller. The obtained results of the optimized and the non-optimized fuzzy controllers are compared to the uncontrolled responses of the structure. Also, the performance of the utilized method is compared with various classical and advanced optimization algorithms.

• The KIPS Transactions:PartC
• /
• v.14C no.7
• /
• pp.611-620
• /
• 2007

Distributing the routing path over the entire network is an important factor to maintain the lifetime of wireless sensor network as long as possible. This paper proposes a fuzzy routing protocol that decides a routing path based on the fuzzy control rules. The fuzzy controller receives the energy values, distances, and hop counts of possible route paths as input, and the inference engine produces the contribution factors for each of route paths. The route path with the largest contribution factor is elected as the final routing path. The nodes contained in the routing path reduce their energy after transmitting a data packet so as to prevent the same route path from being selected repeatedly. It makes the network traffic spreaded over the network resulting longer network lifetime. The computer simulations on TinyOS have shown that the fuzzy routing protocol is more energy efficient and has longer network lifetime compared to the existing routing protocols.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2004.05a
• /
• pp.86-91
• /
• 2004

As many organizations are searching for ways to compete more effectively in today's market environment. Image of Product is become the most important fact to improve their competition. The objectives of this paper are to provide an overview of PDM(Purchasing Decision Factor) and to discuss how to measure it more efficiently. This study develops a conceptual 'relation model of the purchasing decision factor', which identifies only performance based measurement, and proposes Fuzzy Measuring Method which uses the Fuzzy rule based algorithm to adept survey to date sets.

• Journal of Institute of Control, Robotics and Systems
• /
• v.13 no.4
• /
• pp.329-334
• /
• 2007

This paper deals with self-tuning of fuzzy control systems. The fuzzy logic controller(FLC) has parameters that an: input and output scaling factors to effect control output. Tuning method is proposed for the scaling factor. In this paper. it is studied to control and to monitor the remote system statues using SOAP for communicate between the server part and the client part. The remote control system is controlled by using a web browser or a application program. The server part is waiting for the request of client part that uses internet network for communication each other and then the request is reached. the server part saves client data to the database and send a command set to the client part and then the client part sends command to controller in a cool chamber. The administrator can control and monitor the remote system just using a web browser. The effects of membership functions, defuzzification methods and scaling factors are investigated in the FLC system.

• Proceedings of the KIEE Conference
• /
• 1993.07a
• /
• pp.251-253
• /
• 1993

This paper proposes an automatic tuning fuzzy controller for frequency control of a hydro power plant (HPP). The proposed automatic tuning fuzzy controller consists of fuzzy control part and scaling factor calculation part. Scaling factor tuning is based on the concept of conventional tuning rules for the PI controller. The proposed controller was evaluated by simulation. Good results have been obtained for the 5kW model HHP.

• Proceedings of the KIEE Conference
• /
• 1996.07b
• /
• pp.990-992
• /
• 1996

The design of I/O scaling factors for fuzzy controller system is proposed in this paper. The proposed method is for nonlinear input scaling factor and variable output scaling factor. The fuzzy controller is evaluated by computer simulation on the 1st order process and 2nd order process. Simulation results showed robust characteristics for variable reference signal.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.3 no.2
• /
• pp.138-145
• /
• 2003

Performance assessment was introduced to improvement of self-directed learning and method of assessment for differenced learning as the seventh educational curriculum is enforced. Performance assessment is overcoming limitation about problem solving ability and higher thinking abilities assessment that is problem of a written examination and get into the spotlight by way for quality of class and school normalization. But, performance assessment has problems about possibilities of assessment fault by appraisal, fairness, reliability, and validity of grading, ambiguity of grading standard, difficulty about objectivity security etc. This study proposes fuzzy performance assessment system to solve problem of the conventional performance assessment. This paper presented an objective and reliable performance assessment method through fuzzy reasoning, design fuzzy membership function and define fuzzy rule analyzing factor that influence in each sacred ground of performance assessment to account principle subject. Also, performance assessment item divides by formation estimation and subject estimation and designed membership function in proposed performance assessment method. Performance assessment result that is worked through fuzzy performance assessment system can pare down burden about appraisal's fault and provide fair and reliable assessment result through grading that have correct standard and consistency to students.

• Proceedings of the KIEE Conference
• /
• 1992.07b
• /
• pp.1238-1241
• /
• 1992

The series type DC motor is normally nonlinearly modeled, but in this paper, the nonlinear model is linearized for the speed control. The proposed algorithm is constructed by the fuzzy logic controllers. Then the system is investigated for the effects of changes by the scale factor, and fuzziness of fuzzy variables.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.32B no.6
• /
• pp.828-839
• /
• 1995

Although the fuzzy logic controller(FLC) has been adopted in many engineering applications, its performance is not guaranteed since there is no definite theoretic analysis. It may be the main factor that one hesitates to adopt the FLC in critical applications. In this paper, observing the similarity in the pattern of control input between the FLC and a conventional robust controller, i.e., the variable structure controller, we present theoretic analysis for robustness of a fuzzy control system based on the Lyapunov theory.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 1999.11a
• /
• pp.240-246
• /
• 1999

This parer proposes fuzzy reasoning algorithm for improvement in Zonal Cavity Method that is difficult to calculate average illumination without lighting scope and reflection factor so on. This parer use fuzzy reasoning algorithm for maintainment of the best illumination in spite of some variation those are influenced of room illumination and cut down the difficult to be calculated used Zonal Cavity Method.