• 대한기계학회논문집A
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• 제33권11호
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• pp.1294-1299
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• 2009

The Korean tilting train called Hanvit 200 was launched recently in Korea to improve train speed up to 200 km/h at conventional lines. In this paper, we propose a HILS system for simulations of mechanical braking of the Hanvit 200 train using actual ASCU, actual dump valves, Simulink, dSPACE board, and ControlDesk software. In the proposed HILS system, dynamics of wheelsets, bogies and car body, brake force generation, creep force generations are realized via mathematical models, and anti-skid logic is realized using actual components. The validity of the proposed HILS system is demonstrated via comparing results of real-time and off-line simulations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.264-267
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• 1995

In indirect vector control, if the value or the rotor tine constant used in slip calculation is different from the actual rotor time constant because of the temperature rising and flux saturation level, model flux angle and actual flux angle is different so that the transient and steady state response is degraded. In this paper, flux deviation angle is calculated by using actual torque and reference torque, and this flux deviation angle is summed to slip angle, therefore rotor flux angle is always accurate and indirect vector control is satisfied.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 추계학술대회 논문집
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• pp.23-26
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• 2001

This paper presents a digital motion control system for Reluctance Synchronous Motor (RSM) drives with direct torque control (DTC). The system consists of stator flux observer, torque estimator: two hysteresis band controllers, an optimal switching look-up table, IGBT voltage source inverter(VSI), and TMS320C31 DSP controller by using fully integrated control software. The stator flux observer is based on the combined voltage and current model with stator flux feedback adaptive control of which inputs are current, voltage and actual rotor angle for wide speed range. In order to prove the suggested motion control algorithm, There are some simulation and testing at actual experimental system. The developed digitally high-performance motion control system are shown a good motion control response characteristic results and high performance features using 1.0Kw RSM.

• 대한수학교육학회지:수학교육학연구
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• 제11권2호
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• pp.341-349
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• 2001

Infinity is one of the important concept in mathematics, science, philosophy etc. In history of mathematics, potential infinity concept conflicts with actual infinity concept. Reason that mathematicians refuse actual infinity concept during long period is because that actual infinity concept causes difficulty in our perceptions. This phenomenon is called epistemological obstacle by Brousseau. Potential infinity concept causes difficulty like history of development of infinity concept in mathematics learning. Even though students team about actual infinity concept, they use potential infinity concept in problem solving process. Therefore, we must make clear epistemological obstacles of infinity concept and must overcome them in learning of infinity concept. For this, it is useful to experience visualization about infinity concept. Also, it is to develop meta-cognition ability that students analyze and control their problem solving process. Conclusively, students must adjust potential infinity concept, and understand actual infinity concept that is defined in formal mathematics system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.334-340
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• 2002

This paper proposes a new anti-slip re-adhesion control system fur electric railway vehicle driven by inverter-fed induction motors. This paper introduces an instantaneous tangential farce coefficient estimator between driving wheel and rail, which is based on disturbance observer. The torque command of proposed system regulates to exceed this estimated tangential farce coefficient in order to avoid undesirable slip phenomenon of driving wheels. We have already proposed the anti-slip re-adhesion control system based on disturbance observer for simplified one wheel equivalent model successfully. This paper extend to this system to the actual bogie system, which has four driving wheels driven by two induction motors fed by one inverter. In order to apply anti-slip re-adhesion control to the actual bogie system a new anti-slip re-adhesion control based on both disturbance observer and speed sensor-less vector control of induction motor with quick response are combined. The experimental results and the numerical simulation results prove the validity of the proposed control system.

• 드라이브 ㆍ 컨트롤
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• 제15권3호
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• pp.8-13
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• 2018

This paper presents a phase portrait analysis-based safety control algorithm for excavators, using adaptive sliding mode control. Since working postures and material types cause the excavator's rotational inertia to vary, the rotational inertia was estimated, and this estimation was used to design an adaptive sliding mode controller for collision avoidance of the excavator. In order to estimate the rotational inertia, the recursive least-squares estimation with multiple forgetting was applied with the information of the swing velocity of the excavator. For realistic evaluation, an actual working scenario-based performance evaluation was conducted. Based on the estimated rotational inertia and an analysis of estimation errors, sliding mode control inputs were computed. The actual working scenario-based performance evaluation of the designed safety algorithm was conducted, and the results showed that the developed safety control algorithm can efficiently avoid a collision with an object in consideration of rotational inertia variations.

• 디지털융복합연구
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• 제19권8호
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• pp.49-57
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• 2021

본 연구의 목적은 자기통제 차원의 통제 소재 차원과 조직통제 차원의 경직성 문화 차원이 정보보안 태도에 미치는 영향력을 확인하는 것이다. 연구는 통제 소재와 경직성 문화의 교차방안으로 구조화되었고, 정보보안 태도는 정보보안 실제 태도, 준수행동 태도, 정보보안 효능감의 세 가지 변수들로 이루어졌다. 연구 결과, 통제 소재 차원이 정보보안 태도에 끼치는 효과는 통계학적으로 유의미한 것으로 실증되었다. 즉, 정보보안 실제 태도, 준수행동 태도, 정보보안 효능감에 영향력을 미치고 있었으며, 내적통제 조건의 영향이 외적통제 조건보다 더 큰 것으로 실증되었다. 두 번째로 경직성 문화 차원이 정보보안 태도에 끼치는 효과는 통계학적으로 유의미한 것으로 실증되었다. 즉, 준수행동 태도, 정보보안 효능감에 영향력을 미치고 있었으며, 경직된 문화 조건의 영향이 느슨한 문화 조건보다 더 큰 것으로 실증되었다. 아울러, 논의점은 이러한 결과들을 중심으로 정보보안에 요구되는 내용들을 중심으로 학술적, 제도적 지향성을 설명하였다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 추계학술발표회논문집(1)
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• pp.79-84
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• 1996

The robust controller for the nuclear reactor power control system is designed. The reactor model is set up by use of the point kinetics equations and the singly lumped energy balance equations. Since the model is different from the actual plant, the controller which makes the system robust is necessary. The perturbation of the actual plant is investigated with respect to several possible sources of uncertainty. Then the overall system is configured into the two port model and the $H_{\infty}$ controller is designed. The loop shaping and the permissible control rod speed are considered as the design constraints. The designed $H_{\infty}$ controller provides the sufficient margins for the robustness, and the system output as well as the control input satisfy their relevant requirements.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.415-417
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• 2005

This paper proposes tracking control method using pseudo-backstepping control for wheeled mobile robots with nonholonomic constraints. First, the pseudo commands for forward linear velocity and angular velocity are chosen based on the kinematics. Then, the actual torque control inputs are designed to make the actual forward linear velocity and angular velocity follow the pseudo commands. Both semi-global practical posture(position and heading direction angle) stabilization and trajectory tracking are achieved for reference trajectories such as straight line and sinusoidal curve. The stability and performance analysed and numerical simulations are performed to confirm the effectiveness of the proposed scheme.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국제학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.921-927
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• 1988

The process and results of computer simulation using bond graphs for a hydraulic system driving large rotational inertia are presented in this paper. As the large rotational inertia and its application characteristics, control criteria of this system is not position-control nor velocity-control but appropriate acceleration, deceleration and inching ability. All the components' nonlinear characteristics are modelled using bond graphs. The equationing and solution process is carried out by a package. Finally it is concluded that modelling of this kind of system by bond graphs and using a software as its solver shows good approximated results to actual experimental data, and that the proposed modelling may be useful to actual design process for this kind of hydraulic system.