• 대한교통학회지
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• 제23권6호
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• pp.7-18
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• 2005

현재 우리나라의 설계속도는 도로의 기능, 지역특성, 지형에 의해 결정하도록 규정하고 있다. 그러나 도로의 기능을 구분하는 뚜렷한 기준이 없어 적정 설계속도 결정에 설계자의 주관이 개입될 여지가 많으며, 기능분류가 단순하여 설계에 반영되지 못하는 도로기능이 존재하고, 지역분류기준 또한 모호하여 주변지역의 토지이용 특성을 제대로 반영하지 못하였다. 한편 도로가 통과하는 지역의 지형적 특성을 충분히 고려치 않고 단순히 교통소통 만을 강조하여 지나치게 높은 설계속도로 설계하여 도로의 건설비가 증가하고 있다. 따라서 본 연구에서는 지방부 도로 기능분류 및 설계속도 결정에 계획교통량 규모를 반영토록 하여 설계자의 주관적 판단소지를 줄이고 경제적 효율성을 기하였으며, 도시부 기능을 세분화하여 기능분류의 단순함과 설계에 반영되지 못하는 도로의 기능이 존재하는 문제를 해결하였다. 또한 GIS의 지형고도 데이터를 이용하여 지형을 구분하는 구체적 기준을 제시하였다. 즉 기능, 지역, 지형요소를 보다 세분하여 고려하고, 보완기준으로 계획교통량을 추가한 새로운 기능분류와 설계속도 결정기준을 제시하였다.

• 디자인학연구
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• 제17권3호
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• pp.123-132
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• 2004

이 논문은 한국의 환경에 맞는 한국형 고속전철 디자인 방법과 그 디자인 과정을 한국의 환경에 맞추어 연구하고, 그로부터 이루어진 결과를 바탕으로 공기역학적 최적화에 초점을 둔 시제차량(prototype test train, HSR 350${\times}$)의 외형형상 디자인 개발의 형태로 밝힌다. 이는 고속전철 기술개발 사업의 일환으로 1996년부터 2002년까지 6년간 진행되었다. 그 사업의 최종 결과로 제작된 시제차량은 두개의 동력차와 두개의 동력대차 그리고 세 개의 객차로 구성되어 있으며, 2003년에 경부고속전철 선로에서 최고 380km/h까지 성공적으로 시험을 마쳤다. 그러나 시제차량의 디자인 개발과 제작에서는 턱없이 부족한 진행일정과 경제적 제한으로 많은 것들이 유보되었다. 따라서 시제차량에서는 구현되지 못하였으나 향후 미래에 필요성을 염두에 두어, 시제차량과 병행하여 상용차량과 차세대 차량을 위한 보다 개선된 개념 디자인 연구가 진행되었다.

• Journal of Advanced Marine Engineering and Technology
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• 제20권4호
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• pp.27-35
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• 1996

The ship's propulsion efficiency depends upon a combibation of engine and propeller. The propeller has better efficiency as the engine has lower rotational speed. This situation led the engine manufacures to design the engine that has lower speed, longer stroke and a small number of cylinders. With this new trends the conventional mechanical-hydrualic governors for engine speed control have been replaced by digital speed controllers which adopted the PID control or the optimal control algorithm. But these control algorithms have not enough robustness to suppress the variations of the delay-time and the parameter perturbation especially in low speed engine. In this study we consider the perturbations of the engine parameters as the modeling uncetainties and design a robust speed controller for marine medium speed diesel engine by means of $ extit{H}_{infty}$control theory having the central solution. By comparing the results of the robust speed controller with those of mechanical governor and PID controller, the validity of the robust speed controller under parameter variations is confirmed. The speed control of the experimental diesel engine of carried out using actuator which is composed of PWM signal generator and D.C servo motor.

• Journal of Advanced Marine Engineering and Technology
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• 제20권4호
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• pp.349-349
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• 1996

The ship's propulsion efficiency depends upon a combibation of engine and propeller. The propeller has better efficiency as the engine has lower rotational speed. This situation led the engine manufacures to design the engine that has lower speed, longer stroke and a small number of cylinders. With this new trends the conventional mechanical-hydrualic governors for engine speed control have been replaced by digital speed controllers which adopted the PID control or the optimal control algorithm. But these control algorithms have not enough robustness to suppress the variations of the delay-time and the parameter perturbation especially in low speed engine. In this study we consider the perturbations of the engine parameters as the modeling uncetainties and design a robust speed controller for marine medium speed diesel engine by means of $ extit{H}_{infty}$control theory having the central solution. By comparing the results of the robust speed controller with those of mechanical governor and PID controller, the validity of the robust speed controller under parameter variations is confirmed. The speed control of the experimental diesel engine of carried out using actuator which is composed of PWM signal generator and D.C servo motor.

• 제어로봇시스템학회논문지
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• 제10권3호
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• pp.232-238
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• 2004

The brake system of a high-speed train has a crucial role for the safety of human mass transportation. However, it is hard to acquire design parameters of the brake system in the design step of the new high-speed train. In this paper, we build a HILS (Hardware In-the- Loop Simulation) system for the brake system of the Korea High-Speed Train (KHST) that is supposed to run up to 350 km/h, and analyze the characteristics of the brake system of the KHST (composed of 7 cars) via real-time simulations. In the HILS system that is built using a DSP board of dSPACE, the dynamics of the 7 car bodies and several bogies and characteristics of springs and dampers of connection devices between cars are considered separately. Simulation results show that the designed brake system of the KHST is valid and satisfies design specifications.

• 한국자동차공학회논문집
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• 제5권5호
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• pp.104-113
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• 1997

In this paper, the effects of intake manifold systems on volumetric efficiency were investigated in the 4-cylinder 4-stroke cycle diesel engines. The effects of intake manifold system were analyzed on resonant speed and on volumetric efficiency. Resonant speed was calculated by acoustic theory and volumetric efficiency by the method of characteristics. The calculation results agreed well with rest results. It was assured that between the resonant speed and the volumetric efficiency there exists good correlation in multi-cylinder engines. As the results, the prediction of resonant speed was useful to design the optimum intake system. It was assured that the intake manifold systems for BOX-type and RAM-type have different characteristics on the trend of volumetric efficiency. Also a procedure to design the desirable intake manifold system was proposed.

• Journal of Power Electronics
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• 제1권1호
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• pp.19-25
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• 2001

A high speed, three phase, 12/8 pole, 225 kW switched reluctance motor (SRM) has been designed and analyzed. A circuital approach has been used to find the geometry, windings parameters and electromagnetic loading. Then, the 3D finite element method (FEM) has been used to calculate the static torque more accurately and optimize the design. The efficiency of the designed SRM is almost constant over wide range of speed and its phase current is less sensitive to the speed than that of an induction motor of the same rating. Recommendations for manufacturers and users are given.

• Journal of Power Electronics
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• 제16권4호
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• pp.1346-1354
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• 2016

This paper proposes a design guideline for the feedback gain of the adaptive full-order observer in the speed sensorless control of induction machines. The performance of the adaptive full-order observer is dependent on its feedback gain. This paper presents a pole placement method for the observer feedback gain design to improve the estimation performance of the speed adaptive observer. In the proposed method, the observer poles can be chosen independently of the induction motor poles. Instead, they can be positioned according to the operating speed. An analysis and experimental results obtained with the proposed method reveals better performances under general operating conditions.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.67-70
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• 2001

The tool geometry parameters and cutting process have complex relationships. Until now, numerous cutting tests were needed to acquire optimal design of end mill for the purpose of high speed machining, due to the insufficient knowledge about cutting process in high speed machining. Using various tools with different geometry, relationships between tool geometry parameter(rake angle, clearance angle, length of cutter) and cutting process(cutting force, surface accuracy, surface roughness) have been studied. Acquired data can be used to design optimal tool for high speed machining

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.500-503
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• 2003

The tool geometry parameters and cutting process have complex relationships. Until now, various cutting test were needed to acquire optimal design of end mill for the purpose of high speed machining, due to the insufficient knowledge about cutting process in high speed machining. Using various tools with different geometry, relationships between tool geometry parameter (rake angle, clearance angle, length of cutter) and cutting process (cutting force, surface accuracy, surface roughness) have been studied. Acquired data can be used to design optimal tool for high speed machining