• Proceedings of the KSME Conference
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• 2000.04b
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• pp.154-161
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• 2000

As a mass flow controller is widely used in many manufacturing processes for controlling a mass flow rate of gas with accuracy of 1%, several investigators have tried to describe the heat transfer phenomena in a sensor tube of an MFC. They suggested a few analytic solutions and numerical models based on simple assumptions, which are physically unrealistic. In the present work, the heat transfer phenomena in the sensor tube of the MFC are studied by using both experimental and numerical methods. The numerical model is introduced to estimate the temperature profile in the sensor tube as well as in the gas stream. In the numerical model, the conjugate heat transfer problem comprising the tube wall and the gas stream is analyzed to fully understand the heat transfer interaction between the sensor tube and the fluid stream using a single domain approach. This numerical model is further verified by experimental investigation. In order to describe the transport of heat energy in both the flow region and the sensor tube, the Nusselt number at the interface between the tube wall and the gas stream as well as heatlines is presented from the numerical solution.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.641-644
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• 2000

Recently As the performance of the personal computer has been improving rapidly lots of research for the pc-based numerical computer actively progress in an easy repair maintenance and improving the performance with less cost. This paper presents the design using complex programmable logic device(CPLD). The CPU of Motion Controller that function as the real time control of the independent multi-axis motion the error-detect module and external I/O control made use of 80C196KC, In this paper The PC-NC effectively distributed to the load of NCK(numerical computer kernel) and have the advantage of high speed and precision.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.76.1-76
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• 2002

This paper addresses a method for nonlinear controller construction for a general nonlinear system with the separation of controller construction and manipulated values generation. The nonlinear system model is firstly expressed with the coefficients of state-depended representation. The nonlinear control is designed without any approximation based on the model with state-depended representation. At the stage of controller implementation for the nonlinear system, the manipulated values are calculated accurately by use of an algorithm of the numerical analysis. The numerical error for calculating the manipulated value can be reduced to zero by selecting the sampling interval being a small val...

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.352-354
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• 2004

In this paper, a parallel fuzzy controller for one degree of freedom magnetic levitation is designed and its performance is compared with the performance of a PID controller. Input, output scaling factor of fuzzy controller and gain of PID controller were tuned using the GA algorithm. The designed controllers are validated by numerical simulations. So it's shown that parallel fuzzy controller can give the better performance for the plant than PID controller.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2001.05a
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• pp.411-430
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• 2001

This Paper analyses characteristics of the numerical controller industry in market formation and the flow of information between users and producers and the characteristic of knowledge base of the industry and discusses the difficulties derived, from the characteristics, in accumulation of technological capability In market formation between users and producers, the multi-layered market is not favorable to domestic producers in that lower end market is not large enough to provide cradle market to them which produce inferior quality and lower price than imported products. The credibility of the performance of a product is difficult to prove until a critical mass of products are sold. Therefore gaining market share is deterred by unproven credibility of the performance of the product. The flow of information between users and producers is limited. The flow of information on users environment through mass market to producers is essential for improving credibility of a product. The nature of knowledge base is tacit and the means of knowledge transmission is limited. Technological licensing and reverse engineering, which have been conventional means of knowledge transmission, are not useful in the numerical controller industry. These characteristics provide conditions of vicious circle in accumulation of technological capability of the numerical controller industry. It is conjectured that these characteristics are derived from the fact that the numerical controller is the result of IT based technological convergence in controlling machining process. This paper argues that these characteristics of the industry challenges existing approach to R&D management and framework of science and technology Policy.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.68-68
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• 2000

This paper presents a fuzzy modified PID controller that uses linear fuzzy inference method. In this structure, the proportional and derivative gains vary with the output of the system under control. 2-input PD type fuzzy controller is designed to obtain the varying gains. The proposed fuzzy PID structure maintains the same performance as the general-purpose linear PID controller, and enhances the tracking performance over a wide range of input. Numerical simulations and experimental results show the effectiveness of the fuzzy PID controller in comparison with the conventional PID controller.

• Journal of the Korean Society for Marine Environment & Energy
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• v.2 no.1
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• pp.90-101
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• 1999

This paper is concerned with the design of automatic ship maneuvering system including automatic path tracking controller and automatic berthing controller. The optimal control technique is employed to design the automatic path tracking controller, which is based on the linearized equations of ship motion. The numerical example shows that the automatic path tracking controller is capable of tracking the line between way points which are determined by pilot a priori. The decentralized control technique is employed to design the automatic berthing controller. In addition to the automatic path tracking controller, the fuzzy logic controller is used to control the forward speed. The numerical example shows that the automatic berthing controller can be successfully implemented.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.2
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• pp.154-161
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• 2011

This paper is concerned with the modeling and active controller design for elevator lateral vibrations. To this end, a dynamic model for the lateral vibration of the elevator consisting of a supporting frame, cage and active roller guides was derived using the energy method. Free vibration analysis was then carried out based on the equations of motion. Active vibration controller was designed based on the PID control algorithm and applied to the numerical model. Rail irregularity were considered as external disturbance in the numerical simulations. The numerical results show that the active vibration control of elevator is possible.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.55 no.2
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• pp.62-66
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• 2006

This thesis focuses on the design of control schemes for highly efficient BLDC motor drive applications using drives with output capacity of 1Hp. The control system was designed and implemented on a PIC micro-controller and applied to an electric vehicle as a viable replacement to the existing a high phase induction motor that is currently being used for these low cost, small traction drive applications. This paper for the brushless drive research has shown the optimization of the drive system for improved drive design and switching techniques that can improve the entire drive system efficiency for electric vehicle both large and small traction applications using sinusoidal PWM techniques for synthesizing the AC waveforms needed to control these traction drives. In addition, Numerical simulation was conducted to evaluate the performance of designed BLDC Motor using MotorPro simulator.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.57-61
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• 2001

A conceptional framework is proposed in which a general feedback predictive controller is taken to be a feedback interconnection of controller and GPC (General predictive Control). Numerical example are included to illustrate the procedure and to show the performance of the control system.