• 대한기계학회논문집A
• /
• 제21권10호
• /
• pp.1730-1741
• /
• 1997

In this paper, we developed a surface profile measuring system and a profile measuring software for EGL conductor roll. For the profilemeter, we designed a linear guided control system with Laser displacement sensors and developed a 3-dimensional software. Additionally, the AC motor and AC motor driver were used to control the precise position of linear guide system. The measuring principle of the Laser sensor is optical triangulation method. Also, two Laser sensors were used to remove the disturbance and vibration effects of the linear guide system.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 C
• /
• pp.1874-1876
• /
• 2000

In this paper, the effects of the positions of the current probe on the measurements of the ground resistanc, and potential gradients with fall-of-potential method are described, and the testing techniques to minimize the measuring errors are proposed. The fall-of-potential method is theoretically based on the potential and current measuring principle and the measuring error is primarily caused by the position of the measuring auxiliary probes. The ground resistance is calculated by applying the 61.8% lute using fall-of-potential method.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2009년도 춘계학술대회 논문집
• /
• pp.289-292
• /
• 2009

This paper describes the analysis for ground impedance measurement influenced by distance of current probe and frequency using the fall-of-potential method and the testing techniques to minimize the measuring errors are proposed. The fall-of-potential method is theoretically based on the potential and current measuring principle and the measuring error is primarily caused by the position of auxiliary probes. In order to analyze the effects of ground impedance due to the distance of the current probe and frequency, ground impedances were measured in case that the distance of current probe was located from 5[m] to 20[m] and the measuring frequency was ranged in 55[Hz], 128[Hz], 342[Hz], and 513[Hz]. The results could be help to determine the position of current probe when the ground impedance was measured at grounding system.

• Journal of Magnetics
• /
• 제15권4호
• /
• pp.221-224
• /
• 2010

A laboratory sensor model was designed, constructed, and tested based on a newly proposed working principle of magnetic field detection. The principle of sensing employed a time-coded method in correlation with exploiting the advantageous features of the GMI effect. The sensor demonstrated a sensitivity of $10\;{\mu}s/{\mu}T$ in the field range of ${\pm}100\;{\mu}T$. The sensing element in the form of an amorphous thin wire, $100\;{\mu}m$ in diameter ${\times}50\;mm$ long, was fit into a small field modulation coil of 60 mm length. At a magnetic field modulation in the range of hundreds of Hz, the change in time interval of two adjacent GMI voltage peaks was linearly related to the external magnetic field to be measured. This mechanism improved the sensor linearity of the GMI sensor to better than 0.2% in the measuring range of ${\pm}100\;{\mu}T$.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 추계학술대회논문집 II
• /
• pp.1073-1077
• /
• 2001

The objective of this paper is to apply an experimental method based on the principle of reciprocity to measuring the structural intensity. Since only one accelerometer is used in this method it has the advantages of shortening measurement time. reducing accelerometer phase error. overcoming the limitation that the situation should be stationary during the experiment. It has been used to measure the vibration intensity of an infinite beam (beam with damped ends) and a semi-infinite beam (beam with simply supported and damped ends). Results showed that the experiment method based on the principle of reciprocity can be effectively used to measure the structural intensity.

• 대한공업교육학회지
• /
• 제32권1호
• /
• pp.117-133
• /
• 2007

이 연구는 중등학교 학생들에게 비행의 원리를 이해하고 항공 기술 분야에 흥미를 가질 수 있도록 하기 위해 학교 현장에 적용 가능한 교수-학습 자료인 학습용 풍동의 힘 측정 장치를 개발하였다. 연구의 내용은 학습용 풍동의 힘 측정 장치 개발과 실험으로 이루어져 있다. 이 연구에서 얻은 주요 결과를 정리하면 다음과 같다. 공과대학 기계계열 학과나 항공연구소 등에서 사용하는 고가의 Load cell을 이용한 장치 대신에 지렛대 원리를 활용한 간단한 구조이다. 종합된 하나의 장치로 양력, 항력 및 유체 저항 비교 실험이 가능하다. 에어포일 받음각에 따른 양력 계수는 실험값과 이론값이 전체적으로 비슷한 경향성을 갖으며, 실속 현상은 실험값이 이론값보다 더 큰 받음각에서 나타났다. 에어포일 받음각에 따른 항력 계수는 실험값과 이론값이 전체적으로 비슷한 경향성을 갖으며, 실험값은 이론값에 비해 항력 계수의 증가 비율이 완만하게 증가하였다.

• Structural Engineering and Mechanics
• /
• 제54권2호
• /
• pp.379-392
• /
• 2015

A number of acceleration-based damage detection methods have been developed but they have not been widely applied in engineering practices because the acceleration response is insensitive to minor damage of civil structures. In this article, a damage detection approach using the long-gauge strain sensing technology and the principle component analysis technology is proposed. The Long gauge FBG sensor has its special merit for damage detection by measuring the averaged strain over a long-gauge length, and it can be connected each other to make a distributed sensor network for monitoring the large-scale civil infrastructure. A new damage index is defined by performing the principle component analyses of the long-gauge strains measured from the intact and damaged structures respectively. Advantages of the long gauge sensing and the principle component analysis technologies guarantee the effectiveness for structural damage localization. Examples of a simple supported beam and a steel stringer bridge have been investigated to illustrate the successful applications of the proposed method for structural damage detection.

• 펄프종이기술
• /
• 제35권3호
• /
• pp.43-52
• /
• 2003

The new principle to measure a sizing degree by a contact angle was developed using an automatic determination of the 3-end point coordinates of the water droplet on a sheet, which could diminish the operator's bias during measurement. A constant amount of water was first placed on a sample sheet by a water dispenser, and then an image of the liquid droplet was captured by a digital camera and then transmitted to a computer. The program measuring for contact angle extracted a liquid contour by Gaussian function combined with a 8-direction chain code. The Euclidean equation was applied to the binary image of the liquid contour in order to measure the diameter of the contour. Finally, the contact angle of the liquid was calculated by using the diameter and the top coordinates. In addition, a surface free energy of the sample sheet and an elapsed time taken up to the complete absorption into the sheet were simultaneously measured with the contact angle.

• 한국항해학회지
• /
• 제21권2호
• /
• pp.59-67
• /
• 1997

This paper describe the method and the result of making a fiber optic gyrocompass measuring the heading angles of a ship with a fiber optic sensor. As the method seeking for the heading angles, it is possible to get the heading angles by measuring the output signals from a stationary fiber optic sensor in at least three directions such as a heading direction and other two directions having phase difference ${\phi}1$ and ${\phi}2$ to the heading. We made the static fiber optic gyrocompass by a high performance fiber optic sensor having scale factor of 210mV/deg/s and resolution of 0.5deg/hr using this principle. The accuracy of this system was $0.29^{\circ}$ from 20 numbers of data measuring the arbitrary heading angle.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2000년도 추계종합학술대회
• /
• pp.577-580
• /
• 2000

The aim of this paper is to develop a high stable measuring device for radioactive pulses. The device consists of a high voltage supply unit using a fly-back converter principle, and a pulse detection unit for gamma-rays and neutrons. The high voltage supply unit designed can generate DC voltage up to 1,500v at 5V-input, and have a series voltage regulator to maintain the output voltage constantly, resulting in less than 1.63% of voltage regulation. The pulse detection parts consists of an active integrator, a pole-zero circuit, and a 3-stage amplifier of 60 dB, and its frequency bandwidth is from 37 Hz to 300 kHz. From the experimental results, it is confirmed that the measuring device can count at least 10,000 pulses in a second.