• Korean Chemical Engineering Research
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• 제54권6호
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• pp.792-799
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• 2016

Monodisperse silica nanospheres were synthesized by Stober method using rotating cylinder systems with batch or continuous manner. The particle size could be controlled by adjusting the reactant compositions such as the amount of monomer, catalyst, and water in the reaction mixture. The size and monodispersity of the ceramic particles could be controlled by changing the reaction medium with different alcohols other than ethanol or changing the reaction temperature. The effect of Taylor number (Ta) on the average diameter and standard deviation of silica particles were also studied by adjusting the rotation speed of inner cylinder, and the maximum diameter of particles was observed at Ta ${\approx}3,000$.

• 대한기계학회논문집A
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• 제24권11호
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• pp.2762-2770
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• 2000

The refuse incineration plant has an important role in saving the combustion energy for local heating system. But harmful combustion gas(NOx etc.) leads to some serious environmental problem. To reduce the gas, a SCR(Selective Catalytic Reduction)system is installed and it is controlled by adjusting the flow of ammonia gas(NH3) . In this paper, we apply a repetitive control method to reduce NOx by adjusting the flow of ammonia gas for SCR system in a refuse incineration plant which is located in Haeundae, Pusan, Firstly, we analyze the inlet NOx period by FFt method, and verify its periodic variations. Secondly, we design a repetitive control system by using state space model method. Lastly, the effectiveness of repetitive control system is shown by comparing to a conventional PID control in simulation and experimental results.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1366-1370
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• 2010

This paper supposes the vector control algorithm to estimate the rotor position of permanent magnet synchronous traction motor using the hall-effect sensor. The hall-effect provides 60 electrical degrees resolution in rotor position sensing and it is very low resolution. The algorithm makes resolution high as optical encoders or electromagnetic resolver. If necessary, the reference rotor position angle is controlled by adjusting the variable. When a rotor position sensor such as either a optical encoder or a electromagnetic resolver is misalignment, it is useful to align with those. The method on adjusting the reference rotor position angle can compensate for misalignment error degrees by 60 electrical degrees.

• Journal of Electrical Engineering and Technology
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• 제8권3호
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• pp.428-435
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• 2013

Flexible AC Transmission System (FACTS) application study on enhancing the flexibility of AC power system has continued to make progress. A thyristor-controlled series capacitor (TCSC) is a useful FACTS device that can control the power flow by adjusting line impedances and minimize the loss of power flow and voltage drop in a transmission system by adjusting line impedances. Reduced power flow loss leads to increased loadability, low system loss, and improved stability of the power system. This study proposes the optimal location and compensation rate method for TCSCs, by considering both the power system loss and voltage drop of transmission systems. The proposed method applies a multi-objective function consisting of a minimizing function for power flow loss and voltage drop. The effectiveness of the proposed method is demonstrated using IEEE 14- and a 30-bus system.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2000년도 추계학술대회 논문집(Proceeding of the KOSME 2000 Autumn Annual Meeting)
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• pp.135-142
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• 2000

The adjusting parameter set which enable control systems to locate on stability limit can be derived from theoretical or trial methods for an existing real system. The data from the results are much available to keep a system in the Proper stability condition even to site engineers who are inexperienced in the control system. In this paper, a general one loop control system was adopted for a model system the process of which was assumed to consist of a time-delay element and a first order-lag element in series. After obtaining the corresponding parameter set for the model system by mathematical procedures, their loci on the parameter space was taken according to frequency change. The parameter set loci of stability limit showed unique pattern, and particularity , the curves on the Kg-Ti parameter space were able to be generalized in the form of, an unique exponential formula. These properties were also compared with the results taken from experimental procedures by Nyquist response method and Ziegler & Nichols method on the time domain, and both results were confirmed to be nearly same.

• 한국멀티미디어학회논문지
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• 제3권6호
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• pp.643-651
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• 2000

초고속 인터넷의 멀티미디어 서비스 통합에 대한 해결책으로 ATM네트워크 기술이 널리 사용되고 있다. 특히 ABR과 UBR 서비스 클래스는 데이터 애플리케이션을 지원하기 위해 발전되었다. 본 논문에서는, UBR 서비스 상에서는 빠른 재전송과 회복 (FRR) 및 Nagle's 알고리즘의 적용과, ABR 서비스 강에서는 EFCI 스위치 파라미터 조절을 통한 TCP 데이터의 전송성능 향상 효과를 시뮬레이션을 통해 분석하였다. 본 연구의 결과로, ATM 네트워크 상에서 TCP의 성능향상은 TCP 파라미터의 조절과 효과적인 스위치 파라미터의 설정을 통해 가능해 짐을 알 수 있었다.

• Journal of Mechanical Science and Technology
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• 제14권10호
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• pp.1081-1088
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• 2000

In this paper, a compliance control strategy for robot manipulators that employs a self-adjusting stiffiness function is proposed. Based on the contact force, each entry of the diagonal stiffness matrix corresponding to a task coordinate in the operational space is adaptively adjusted during contact along the corresponding axis. The proposed method can be used for both the unconstrained and constrained motions without any switching mechanism which often causes undesirable instability and/or vibrational motion of the end-effector. The experimental results involving a two-link direct drive manipulator interacting with an unknown environment demonstrates the effectiveness of the proposed method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1800-1803
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• 2002

The pulsed power system was widely making use good of many industrial and environments. The pulse generator generally required for short pulse duration and high peak value was forced to consider its volume and economy. In this paper, this system is designed and fabricated which has a compact size of pulse generator with switched MOSFET. We have studied the removal of rust material using Arc discharging in pulsed power system. It have tested their characteristics by adjusting variable voltage charging and pulse repetition rate. As a result, We can eliminate rust materials with this device.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.425-426
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• 2006

This study proposes a new simulation method of high speed rotor system with the dynamic model using multi body dynamic analysis tool and with a new phase modulating technique as a system control algorithm. A dynamic model of high speed rotor system was built by, ADAMS, commercial multi body dynamic program. The phase modulating technique is a new control algorithm for a rotor system. This algorithm can control system using an adaptive proportional gain and an adaptive phase which are obtained from periodical input signal. To make control system, a ADAMS model and component parameters and phase controller was composed by Matlab Simulink And simulate it.

• 한국정밀공학회지
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• 제16권8호
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• pp.38-45
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• 1999

The 2-trowel type concrete floor finishing robot can move in any direction by adjusting the posture or trowels without any wheels. Since the quality of the smoothed and polished concrete floor is determined by plastering speed, we need to control the velocity of the robot. However, we cannot use the typical motion control method because it is very difficult to measure the velocity of the robot, in contrast to the mobile robots with wheels. To overcome this difficulty, the following are studied in this paper: we found that the robot dynamics has the disturbance depending on its translational speed, and showed that there exists the saturated velocity of the robot which is set by the posture of the trowels, and obtained the relationship between the saturated velocity and the posture in the translation. The result enables us to control the motion of the robot only by adjusting the posture of trowels without measuring the velocity of the robot. Currently, we built the troweling robot and are experimenting its performance with the proposed motion control method.