• 동력기계공학회지
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• 제19권4호
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• pp.89-96
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• 2015

This paper investigates some strategies to overcome the chattering problem of the conventional sliding mode observer (SMO) and to improve the rotor position estimation performance for full range sensorless control of a PMSM. An adaptive observer gain based on the Lyapunov's stability criterion and a cascade low pass filter with advanced phase delay compensation were proposed to reduce the chattering problem and to strengthen the filtering capability of the SMO. Several cases studies through experiments were carried out to confirm conventional SMO's problems and effectiveness of the proposed strategies. The experimental results show that the proposed method gives precise estimation on speed and rotor position when the motor rotates on 2% of its rated speed.

• 한국광학회지
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• 제7권2호
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• pp.112-119
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• 1996

TM 편광된 광자가 frustrated total internal reflection(FTIR) 구조에서 2차원적 터널링을 할 때 터널링에 소요되는 시간과 터널링되어 나오는 위치를 계산하였다. 이는 TM 편광된 광자의 FTIR 터널링 문제를 효과질량이 다른 이종 포텐셜 장벽을 터널링하는 전자의 문제로 변환시킴으로써 가능하였다. 계산된 결과를 TE 편광된 광자에 대한 경우와 비교하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.102-109
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• 1997

A study to determine a proper sensor placement was developed to improve force identification. Improper selection of response position cause erroneous result in force identification problem. This paper presents two methods to improve the conditioning of the system's FRM(Frequency Response Matrix) which affects the accuracy of result. The basic strategy of the two methods in selecting the response position is to let the smallest singular value be as large as possible by maximizing the orthogonality of FRM. The suggested methods are tested numerically with a fixed-fixed beam model. The test results show that the proposed methods are very effective in dealing with the force identification problem.

• Structural Engineering and Mechanics
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• 제4권1호
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• pp.49-59
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• 1996

This paper considers large deflection problem of a simply supported beam with variable are length subjected to a point load. The beam has one of its ends hinged and at a fixed distance from this end propped by a frictionless support over which the beam can slide freely. This highly nonlinear flexural problem is solved by elliptic-integral method and shooting-optimization technique, thereby providing independent checks on the new solutions. Because the beam can slide freely over the frictionless support, there is a maximum or critical load which the beam can carry and it is dependent on the position of the load. Interestingly, two possible equilibrium configurations can be obtained for a given load magnitude which is less than the critical value. The maximum arc-length was found to be equal to about 2.19 times the fixed distance between the supports and this value is independent of the load position.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2240-2242
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• 2001

A rotary double inverted pendulum, the nonlinear system has a regulation problem. In this paper, we linearize the nonlinear system at the upright equilibrium position. The linearized system can be expressed in state space. To maintain the upright position, we design a feedback controller using LQR(Linear Quadratic Regulator) algorithm. Then we simulate the system with third-order Adams Bashforth Moulton Method. The simulated result shows that the applied algorithm is effective for the regulation problem.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.901-905
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• 2005

It is very important to arrange landmarks when a mobile robot needs to measure its own location. So, it has been discussed often how to arrange landmarks in the optimal way until now. We, there, chose the RFID (Radio frequency Identification) tags as landmarks which can be observed by a mobile robot, and demonstrated the possibility of the optimal arrangement of them. For this work first, we defined the optimization problem and its parameters for the arrangement of tags. Second, we proposed the algorithm which can be applied to the optimization problem. Finally we could obtain closely optimal and practical arrangement with the minimum number of landmarks which satisfied the necessary condition by experimentation.

• 산업경영시스템학회지
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• 제19권39호
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• pp.19-26
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• 1996

A solution procedure to minimize the number of storage carousels has been developed under the carousel throughput rate and total storage capacity requirements. The number of carousels can be reduced by increasing the throughput rate of carousels which depends upon the size of carousels, the storage item allocation to carousels, and the item position assignments in each carousel. Since the problem is very complicated and hard to solve optimally, the following solution procedure to solve the problem hierarchically is proposed: With a given number of carousels, the storage items are allocated to carousels so that the slowest average transaction time among carousels may be minimized, and then the position of each item is assigned in the allocated carousel so that the throughput of the carousel can be maximized.

• 한국컴퓨터정보학회논문지
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• 제24권11호
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• pp.119-126
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• 2019

부분역최적화는 역최적화의 흥미로운 변형으로, 주어진 최적화문제와 그 문제의 부분해가 주어지면 이 부분해가 최적해에 포함되도록 문제를 최소한으로 수정하는 문제이다. 이 논문은 라인위에서 정의되는 순환외판원문제(TSP)를 다루는데, 이는 배달시스템, 창고 선반에서 물건을 수집하는 것, 등의 많은 응용을 가진다. 라인 위에서 위치하는 n개의 일이 주어지고 이 중 연속적으로 처리해야하는 일 k개가 부분적으로 주어진다. 각각의 일은 라인 위의 특정 장소에 위치하고 라인을 움직이는 서버에 의해 처리되어야 한다. 우리의 임무는 k개의 일이 최적해에서 연속적으로 처리되도록 n개의 일의 위치를 라인 위에서 최소한으로 조정하는 것이다. 이 논문에서 이 문제와 이 문제의 다양한 변종을 다항시간 내에 푸는 알고리즘을 개발한다. 구체적으로, 서버가 특정한 Forward Trip이라는 특정한 내부 알고리즘을 사용하는 경우와 일반적인 최적 알고리즘을 사용하는 경우에 대한 부분역최적화를 다룬다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.772-777
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• 2003

A vision-based tool position estimation system for the inspection and maintenance manipulator working inside the steam generator bowl of nuclear power plants can help human operators ensure that the inspection probe or plug are inserted to the targeted tube. Some previous research proposed a simplified tube position verification system that counts the tubes passed through during the motion and displays only the position of the tool. In this paper, by using a general camera calibration approach, tool orientation is also estimated. In order to reduce the computation time and avoid the parameter bias problem in an ellipse fitting, a small number of edge points are collected around the large section of the ellipse boundary. Experiment results show that the camera calibration parameters, detected ellipses, and estimated tool position are appropriate.

• 경영과학
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• 제34권2호
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• pp.103-113
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• 2017

The artillery is a key element of the ground forces operation during wartime, and the military engineers support the artillery position development operation to support the smooth operation of the artillery. In establishing the artillery position development operation plan, the commander requires more than his intuition to find the best option reflecting a number of elements of the battlefield situation which changes every minute. Moreover, the number of available equipment is smaller than the number of required position developments, and the effective equipment operation becomes essential element of this issue. This study quantified the capability of the available engineering equipment, organized a number of teams enabling equipment to put out the maximum capacity based on the quantified figures, and formed the model which allocates the team to the developing points to minimize the developing time. The goal programming method was applied to resolve the problem. The developed model was applied to compare the total mission duration following the number of teams, the variable for commander's decision, and the result of this study can be used as the quantitative data for commander's decision making process in establishing the artillery position development support operation through effective equipment management.