• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.60-63
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• 1997

A new approach to the position sensor elimination of PM synchronous motor drives is presented in this study. Using the position sensing characteristics of PMSM itself, the actual rotor position as well as the machine speed can be estimated by adaptive flux observer and used as the feedback signal for the vector controlled PMSM drive. The adaptive speed estimation is achieved by model reference adaptive technique. The adaptive laws are derived by the Popov's hyperstability theory and the positivity concept. In order to verify the effectiveness of the proposed scheme, computer simulations are carried out for the actual parameters of a PM synchronous motor and the results well demonstrate that the proposed scheme provides a good estimation value of the rotor speed without mechanical sensor. It is also shown that the actual rotor position as well as the machine speed can be achieved under the variation of the magnet flux linkage. Since the flux linkages are estimated by the adaptive flux observer and used for the identification of the rotor speed, robust estimation of the rotor speed can be performed.

• 한국자동차공학회논문집
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• 제11권6호
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• pp.108-117
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• 2003

Development of advanced restraint system challenges both restraint and automobile manufacturers to come up with proper airbag design to reduce occupant out-of-position related injury. The important component of the advanced restraint system is the multi stage inflator. The multi stage inflator can independently control two or more airbag inflation stages to maximize occupant protection. The objective of this research is to develop relationship between airbag inflation characteristics, the occupant positions and the airbag design variables. The tests are conducted using five kinds of inflators, two kinds of airbag cushion folding methods and two kinds of tear lines. In the case of inflator, the out-of-position tests are performed with a traditional inflator, a depowered inflator and a dual stage inflator. And the efficiency and injury mechanism are evaluated by analyzing the injury pulses and values. Using this relationship, airbag design guideline is established for airbag aggressivity thresholds and the risk of injury is identified according to occupant positions.

• 동력기계공학회지
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• 제20권4호
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• pp.83-90
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• 2016

This study proposes a high-performance PI controller design method for an oil cooler system in conjunction with zero position adjustment and the characteristic parameters in its closed loop control system. The characteristic parameters included PI gains are decided by design specifications such as settling time and overshoot. The fine tuning on decided gains was performed by adjustment the zero position to get more desirable control performances. The simulations and experimental results show that the proposed PI controller design for an oil cooler system was possible to accomplish good control performances and to satisfy the design specifications.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 추계학술대회 논문집
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• pp.214-219
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• 2001

For navigation of a mobile robot, it is one of the essential tasks of find out its current position. Dead reckoning is the most frequently used method to estimate its position. However conventional dead reckoner is prone to give us false information on the robot position especially when the wheels are slipping. This paper proposes an improved dead reckoning scheme using neural networks. The network detects the instance of wheel slipping and estimates the linear velocity of the wheel ; thus it calculates current position and heading angel of a mobile robot. The structure and variables of the neural network are chosen based on the analysis of slip motion robot. The structure and variables of the neural network are chosen based on the analysis of slip motion characteristics. A series of experiments are performed to investigate the performance of the improved dead reckoning system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.599-604
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• 2002

Substructures position is considered as design parameter to obtain optimal structural changes to raise its dynamic characteristics. In conventional SDM (structural dynamics modification) method, the layout of modifying substructures position is first fixed and at that condition the structural optimization is performed by using the substructures size and/or material property as design parameters. But in this paper as a design variable substructures global translational and rotational position is treated. For effective structural modification the eigenvalue sensitivity with respect to that design parameter is derived based on measured frequency response function. The optimal structural modification is calculated by combining eigenvalue sensitivities and eigenvalue reanalysis technique iteratively. Numerical examples are presented to the case of beam stiffener optimization to raise the natural frequency of plate.

• Journal of Trauma and Injury
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• 제33권3호
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• pp.191-194
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• 2020

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a novel technique to maintain proximal arterial pressure. It is important to locate the balloon catheter correctly in performing REBOA but it is inaccurate to check the catheter position by external measurement. Even if the position of the catheter is initially confirmed by X-ray, it is difficult to determine the location of the catheter that changes according to various situations. We performed REBOA under real-time fluoroscopy and could maintain the catheter in correct position under various situations.

• 한국지구과학회지
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• 제28권1호
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• pp.105-111
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• 2007

우리나라에서의 심부 소형 터널의 탐사에는 주로 탄성파 탐사법이나 지오레이다 탐사법이 사용되어 왔으며, 그중에서 탄성파 탐사는 주로 주시나 진폭을 이용하여 터널의 위치를 해석하였다. 그러나 측정 시추공간의 짧은 거리와 초동의 피킹 오차 등에 의해서 터널의 정확한 위치 해석은 매우 불안정하였다. 이러한 문제를 극복하기 위하여, 본 연구에서는 주시 자료와 진폭 자료의 시뮬레이션에 의한 위치 추적을 시도하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국제학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.832-836
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• 1988

"Motion Stereo" is quite useful for visual guidance of the robot, but most range finding algorithms of motion stereo have suffered from poor accuracy due to the quantization noise and measurement error. In this paper, 3-D position estimation and refinement scheme is proposed, and its performance is discussed. The main concept of the approach is to consider the entire frame sequence at the same time rather than to consider the sequence as a pair of images. The experiments using real images have been performed under following conditions : hand-held camera, static object. The result demonstrate that the proposed nonlinear least-square estimation scheme provides reliable and fairly accurate 3-D position information for vision-based position control of robot. of robot.

• 제어로봇시스템학회논문지
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• 제16권8호
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• pp.804-809
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• 2010

This paper proposes a Taylor-series design method which reduces the height error of the tag when readers are arranged at the same height in 3-dimensional space. The proposed method consists of two steps. Firstly, the planar position is estimated by the Taylor-series method using the TDOA measurement. Next, the height is estimated from the estimated planar position. In order to show the validity of the proposed method, computer simulations were performed for the static case and linear trajectory of the tag. Results show that the proposed method gives convergent estimated position and better height estimate than the Taylor series method.

• The Journal of Korean Physical Therapy
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• 제13권3호
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• pp.829-837
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• 2001

Using Video Display Terminals(VDT) in the working environment often causes health complaints in the neck and shoulder region. This study was conducted on ten subjects, in order to investigate the change of electromyographic activities in the neck region(sternocleidomastoid muscle, upper trapezius muscle and erector muscle of cervical spine)with regards to the screen height and document holder position. A total of six different conditions of screen height and document holder position were measured during subjects performed a text-entry task for a duration of 10min. The raw EMG signal was transmuted into the root mean square(RMS). Two-way ANOVA for repeated measures was used to analyse the effects of the two factors. As a result, changing the screen height and document holder position has no effect on electromyographic activities in the neck region.