• 한국임상보건과학회지
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• 제10권2호
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• pp.1587-1593
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• 2022

Purpose. This study was to investigate the degree of refractive error that occurs depending on the measurement location of the subject when performing a refraction test using the automatic refractor. Methods. When performing the auto-refraction test, measurements were taken while increasing the distance between the forehead and the forehead rest, and the measurements were made by tilting the head clockwise and counterclockwise. Results. During the auto-refraction test, significant refractive error occurred when the forehead was not attached to the forehead support or the subject's head was turned clockwise or counterclockwise. Conclusions. When performing a refraction test using an automatic refractor, the examiner will have to pay attention to whether the subject's forehead is in close contact with the forehead rest, and whether the head is tilted.

• Structural Engineering and Mechanics
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• 제15권3호
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• pp.299-314
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• 2003

This investigation presents an efficient method for identifying modal characteristics from the measured displacement, velocity and acceleration signals of multiple channels on structural systems. A Vector Backward Auto-Regressive model (VBAR) that describes the relationship between the output information in different time steps is used to establish a backward state equation. Generally, the accuracy of the identified dynamic characteristics can be improved by increasing the order of the Auto-Regressive model (AR) in cases of measurement of data under noisy circumstances. However, a higher-order AR model also induces more numerical modes, only some of which are the system modes. The proposed VBAR model provides a clear characteristic boundary to separate the system modes from the spurious modes. A numerical example of a lumped-mass model with three DOFs was established to verify the applicability and effectiveness of the proposed method. Finally, an offshore platform model was experimentally employed as an application case to confirm the proposed VBAR method can be applied to real-world structures.

• 한국지능시스템학회논문지
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• 제21권4호
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• pp.530-535
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• 2011

본 논문에서는 방사 및 연신 공정에 쓰이는 히터 시스템의 정밀온도 제어를 다룬다. 히터 시스템의 정밀온도 제어를 위해 자동동조(auto-tuning) IMC-PID 제어기를 최적화 기법인 uDEAS를 이용해서 설계하는 방법을 제안한다. 이를 위해 롤 히터의 측정 데이터로부터 히터를 근사 모델링하고, 이 모델로부터 안정성과 제어성능을 널리 만족시키는 최적의 IMC-PID 제어기 저역필터 값을 uDEAS로 동조한다. 마지막으로, 설계된 제어기를 DSP 키트를 사용하여 실험하였다.

• 한국안광학회지
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• 제16권4호
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• pp.433-438
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• 2011

목적: 개방형과 가상주시형 자동굴절검사기에 의한 굴절이상도를 비교하여 그 차이를 알아보고 개방형 검사기를 이용하여 정적굴절검사를 시행할 때 주시시표와 피검자와의 최소거리를 알아보고자 하였다. 방법: 교정시력 1.0 이상이고 안과적 질환이 없는 성인(22.2${\pm}$3.4세) 21명(42안)을 대상으로 자동굴절검사기에 의한 굴절검사를 실시하였다. 굴절검사는 가상주시형(RK-F1, Canon, Japan)을 사용하였으며 개방형(N-vision-K5001, Shin-nippon, Japan)을 사용하여 1 m, 3 m, 4 m, 6 m의 위치를 주시하는 상태에서 거리에 따른 굴절이상도를 비교하였다. 결과: 1 m 주시거리에서 개방형에 의한 전체대상자의 평균 굴절이상도(-2.75${\pm}$1.84 D)는 가상주시형에 의한 평균 굴절이상도(-2.95${\pm}$2.04 D)와 유의적인 차이가 없었다(p=0.06). 그러나 3 m, 4 m, 6m 주시거리에서 개방형에 의한 평균굴절이상도는 가상주시형에 의한 굴절이상도보다 낮은 근시성 굴절이상도를 보였다(p<0.05). 결론: 정적굴절검사를 위해 개방형 굴절검사기를 사용하는 경우 5~6 m의 검사거리를 확보하지 않더라도 3 m 이상의 측정거리에서도 가능하다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1999년도 제14차 학술회의논문집
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• pp.194-197
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• 1999

Automatic weld bead removal system is consisted of bead removal tool, bead profile measurement system and tool motion control system. In this paper, design of weld bead profile measurement system which is used for automatic weld bead removal system is described. The system measures the weld bead position, normal vector of the auto-body and weld bead profile. The optical sensor with structured laser beam is used as a sensor and comparison of the sensor that can be used for this purpose is discussed in detail. The measurement process and the related software developed for this purpose are also described. A median filter, average filter and long line filters are used and their effects in bead profile measurement are discussed. The measurement system is integrated into automatic bead removal system and is used to remove weld bead in rear pillar of automotive body. The whole system operates well in automotive body assembly line and thus the system is proved to be good for this purpose.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 추계학술대회 논문집
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• pp.238-242
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• 1992

Thus paper deals with a study of the automatic machining and measurement system based on Features. The system includes following 5 modules : a feature-based design module, an automatic NC programming module, an automatic measurement programming module, and a simulation module. The system is developed by using IBM-PC in the AutoCAD and the BORLAND c $\^$++/ environment. A vertical machining center equipped with FANUC 0MC is used for experiments. Performance of the system is confirmed by a large amount of experiment.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.987-990
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• 2007

The accuracy of sound strength (G) measurement method in ISO 3382 has been questioned. One of the main reason is the difficulty in measuring a reference sound level in an anechoic chamber with the same set-up which was applied for the actual hall measurements. In the present paper, an in-situ measurement method for G was proposed by investigating the present G measurement method shown in ISO 3382. In addition, the sound radiation characteristics of typical omnidirectional loudspeakers were investigated and Phi (O) of auto correlation function (ACF) parameters was also calculated from an actual music excerpt to characterize the sound energy distribution in concert halls.

• Journal of the Optical Society of Korea
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• 제17권5호
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• pp.392-398
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• 2013

As the essential techniques for the CD (Critical Dimension) measurement of the LCD pattern, there are various modules such as an optics design, auto-focus [1-4], and precise edge detection. Since the operation of image enhancement to improve the CD measurement repeatability, a ring type of the reflected lighting optics is devised. It has a simpler structure than the transmission light optics, but it delivers the same output. The edge detection is the most essential function of the CD measurements. The CD measurement is a vital inspection for LCDs [5-6] and semiconductors [7-8] to improve the production yield rate, there are numbers of techniques to measure the CD. So in this study, a new subpixel algorithm is developed through facet modeling, which complements the previous sub-pixel edge detection algorithm. Currently this CD measurement system is being used in LCD manufacturing systems for repeatability of less than 30 nm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.165-167
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• 2001

This paper presents a study on successive approximation measurement of mechanical parameters for motor control system. At the first step of servo system installation, control system gain tuning is troublesome work. Recently, auto-tuning method of motion controller for motor drive system is based on parameter measurement and identification. On the case of first order mechanical system (mechanical parameters are modified by simple inertia and friction), it is necessary for good response to get the accurate measurement or identification of the mechanical parameters. In this paper, novel method applies the binary successive approximation measurement to the inertia and friction coefficient. Computer simulation and experiment for the proposed method will show verification of accuracy and usefulness.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 춘계학술대회 논문집
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• pp.795-796
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• 2007