• Journal of Korean Society for Quality Management
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• v.45 no.2
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• pp.191-207
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• 2017

Purpose: To develop an interactive version of the conventional process capability-based approach, called 'Interactive Process Capability-Based Approach (IPCA)' in multi-response surface optimization to obtain a satisfactory compromise which incorporates a decision maker(DM)'s preference information precisely. Methods: The proposed IPCA consists of 4 steps. Step 1 is to obtain the estimated process capability indices and initialize the parameters. Step 2 is to maximize the overall process capability index. Step 3 is to evaluate the optimization results. If all the responses are satisfactory, the procedure stops with the most preferred compromise solution. Otherwise, it moves to Step 4. Step 4 is to adjust the preference parameters. The adjustment can be made in two modes: relaxation and tightening. The relaxation is to make the importance of one of the satisfactory responses lower, which is implemented by decreasing its weight. The tightening is to make the importance of one of the unsatisfactory responses higher, which is implemented by increasing its weight. Then, the procedure goes back to Step 2. If there is no response to be adjusted, it stops with the unsatisfactory compromise solution. Results: The proposed IPCA was illustrated through a multi-response surface problem, colloidal gas aphrons problem. The illustration shows that it can generate a satisfactory compromise through an interactive procedure which enables the DM to provide his or her preference information conveniently. Conclusion: The proposed IPCA has two major advantages. One is to obtain a satisfactory compromise which is faithful to the DM preference structure. The other is to make the DM's participation in the interactive procedure easier by using the process capability index in judging satisfaction/unsatisfaction. The process capability index is very familiar with quality practitioners as well as indicates the process performance levels numerically.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.4
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• pp.313-318
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• 2010

This paper deals with the relationship between zeros and step response of the second and third order LTI (Linear Time Invariant) SISO (Single-Input and Single-Output) systems with complex poles. Although it has been known that the maximum number of local extrema is less than the number of zeros in the system with only real poles[8], some cases with complex poles are shown in this paper to have many local extrema. This paper proposes monotone nondecreasing conditions and describes the relationship between the transient response and the number of local extrema in step response with each region of zeros.

• Food Science of Animal Resources
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• v.43 no.2
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• pp.374-381
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• 2023

In a previous study, 'response surface methodology (RSM) using a fullest balanced model' was proposed to improve the optimization of food processing when a standard second-order model has a significant lack of fit. However, that methodology can be used when each factor of the experimental design has five levels. In response surface experiments for optimization, not only five-level designs, but also three-level designs are used. Therefore, the present study aimed to improve the optimization of food processing when the experimental factors have three levels through a new approach to RSM. This approach employs three-step modeling based on a second-order model, a balanced higher-order model, and a balanced highest-order model. The dataset from the experimental data in a three-level, two-factor central composite design in a previous research was used to illustrate three-step modeling and the subsequent optimization. The proposed approach to RSM predicted improved results of optimization, which are different from the predicted optimization results in the previous research.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.203-206
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• 1998

This paper describes the procedure of getting information about auto-tuning of PID regulator by the injection of high step input, called limited input, during a transient time of control. The key point is that system identification and control could be continuously executed. This means that the system information obtained by limited input despite of system uncertainty can be continuously applied to the PI regulator. Simulation and experiment result of brushless DC motor system having monotone increasing step response demonstrate the usefulness of proposed auto-tuning algorithm.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.323-325
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• 2009

In this paper, we present simulation results of Dynamic Matrix Control(DMC) to a boiler steam temperature. In order to control of steam temperature, we choose the input-output variables and generate the step response model by each input variable's step test. After that, the control structure executes on-line control with optimization using step response model. Proposed controller is applied to the APESS(Doosan company's boiler model simulator) and it is observed that the simulation results show satisfactory performance of proposed control.

• Steel and Composite Structures
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• v.25 no.3
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• pp.287-298
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• 2017

The present study aims to determine the structural response of full scaled rectangular columns under both of vertical and lateral loads using numerical methods. In the study, the composite columns considering full concrete filled circular steel tube (FCFRST) and concrete filled double-skin rectangular steel tube (CFDSRST) section types are numerically modelled using ANSYS software. Vertical and lateral loads are applied to models to assess the structural response of the composite elements. Also similar investigations are done for reinforced concrete rectangular (RCR) columns to compare the results with those of composite elements. The analyses of the systems are statically performed for both linear and nonlinear materials. In linear static analyses, both of vertical and lateral loads are applied to models as only one step. However in nonlinear analyses, while vertical loads are applied to model as only one step, lateral loads are applied to systems as step by step. The displacement and stress changes in some critical nodes and sections and contour diagrams are reported by graphs and figures. At the end of the study, it is demonstrated that the nonlinear models reveal more accurate result then those of linear models. Also, it is highlighted that composite columns provide more and more safety, ductility compared to reinforced concrete column.

• IE interfaces
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• v.23 no.3
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• pp.257-263
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• 2010

Taguchi defined a good quality as 'A correspondence of product characteristic's expected value to the objective value satisfying the minimum variance condition.' For his good quality, he suggested Taguchi Method which is called Robust design which is irrelevant to the effect of these noise factors. Taguchi Method which has many success examples and which is used by many manufacturing industry. But Optimal solution of Taguchi Method is one among the experiments which is not optimal area of experiment point. On the other hand, Response Surface Method (RSM) which has advantage to find optimal solution area experiments points by approximate polynomial regression. But Optimal of RSM is depended on initial point and RSM can not use many factors because of a great many experiment. In this paper, we combine the Taguchi Method and the Response Surface Method with each advantage which is called Taguchi-RSM. Taguchi-RSM has two step, first step to find first solution by Taguchi Method, second step to find optimal solution by RSM with initial point as first step solution. We give example using catapults.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.3
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• pp.295-302
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• 1998

In this paper, a new auto-tuning PI controller for the speed servo system of a PMSM is designed by using limited step response characteristics. The method is proposed that gets information about auto-tuning of PI regulator by the injection of step input, called limited input, during a transient response time of control. System parameter estimation and speed control could be continuously executed. This means that in despite of system uncertainty the system information obtained by limited input can be continuously applied to the PI regulator. We demonstrate the effectiveness of the proposed auto-tuning algorithm through simulation and experiment result of the speed control for a PMSM having monotone increasing step response.

• Journal of the Korean Institute of Intelligent Systems
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• v.27 no.1
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• pp.50-58
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• 2017

For nonlinear control system design, there are many studies based on TSK fuzzy model. However, TSK fuzzy modelling needs nonlinear dynamic equations of the object system or a data set fully distributed in input-output space. This paper proposes an modelling technique using only step input response data. The technique uses also the genetic algorithm. The object systems in this paper are nonlinear to control input variable or output variable. In the case of nonlinear to control input, response data obtained with several step input values are used. In the case of nonlinear to output, step input response data and zero input response data are used. This paper also presents a fuzzy controller design technique from TSK fuzzy model. The effectiveness of the proposed techniques is verified with numerical examples.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.12
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• pp.1974-1980
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• 2001

The control algorithm of a new type self-bearing step motor is presented. The motor actuator is used for both motor and bearing functionality without any redundant coil windings or redundant electromagnets. The self$.$bearing step motor layout and its control method are described. A linearized farce-current-displacement relationship is derived. As the result of the unbalance response approach, the constant torque production is possible fur the supply current regulation algorithm. And even if the bearing functionality is added in the motor functionality, no additional current for bearing functionality is possible, and this leads to minimize the net power loss. Also, the unbalance response shows the independent bearing force and motor torque.