• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.3
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• pp.52-57
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• 1997

Electronic Speckle Pattern Interferometry(ESPI) using the Model 95 Ar. laser, a video system and an image processor was applied to the in-plane displacement measurements. Unlike traditional strain gauges or Moire method, ESPI method requires no special surface preparation or attachments and can be measured in-plane displacement with no special surface preparation or attachments and can be measured in-plane displacement with no contact and real time. In this experiment specimen was loaded in parallel with a loadcell. The specimen was the cold rolled steel sheet of 2mm thickness, which was attached strain gauges. The study provides an example of how ESPI have been used to measure strain displacement in this specimen. The results measured by ESPI compare with the data which was measured by strain gauge method in tensile testing.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.407-410
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• 2002

Triangulation method, conoscopic holography method and interferometry method are analyzed for effective measurement of micro burr geometry, which is formed in micro drilling. To select proper sensor, cylinder with 0.5mm diameter is measured and the result shows that conoscopic holography method is effective for measuring highly inclined surface. Burr with 1.0mm height and 30$\mu\textrm{m}$ height are measured by all methods. The conoscopic holography method is probed to be most proper method for measuring micro burr. A Program for 3D display of measured burr is developed.

• Journal of Electrical Engineering and information Science
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• v.3 no.3
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• pp.348-354
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• 1998

The measured equation of invariance (MEI) method was introduced as a way to determine the electromagnetic fields scattered from discrete objects. Unlike more traditional numerical methods, MEI method over conventional methods over conventional methods are very substantial. In this work, Haar wavelets are applied to the measured equation of invariance (MEI) to solve two-dimensional scattering problem. We refer to "MEI method with wavelets" as "Wavelet MEI method". The proposed method leads to a significant saving in the CPU time compared to the MEI method that does not use wavelets as metrons. The results presented in this work promise that the Wavelet MEI method can give an accurate result quickly. We believe it is the first time that wavelets have been applied in conjunction with the MEI method to solve this scattering problem.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.6
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• pp.81-87
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• 2003

Triangulation method, conoscopic holography method and interferometry method are analyzed for effective measurement of micro burr geometry, which is formed in micro drilling. To select proper sensor, the cross section of a cylinder with 0.5mm diameter is measured and the result shows that conoscopic holography method is effective for measuring highly inclined surface in cylinder. Burrs with 1.0mm and 30${\mu}{\textrm}{m}$ height are measured by three suggested methods. As a result, the conoscopic holography method is proved to be most proper in measuring burr geometry. Burr measurement system is developed, which consists of conoscopic laser sensor, X-Y table, controller and burr measurement program. Burrs can be measured automatically and the result is displayed in 3D shape

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.10a
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• pp.116-120
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• 2001

Fiber fracture is one of the dominant failure phenomena to determine total mechanical properties in composites. Fiber fracture locations were measured by optical microscopic method and acoustic emission (AE) as functions of matrix toughness and surface treatment by the electrodeposition (ED), and then two methods were compared. Two AE sensors were attached on the epoxy specimen and fiber fracture signals were detected with elapsed time. The interfacial shear stress (IFSS) was measured using tensile fragmentation test and AE system. In ED-treated case, the number of the fiber fracture measured by an optical method and AE was more than that of the untreated case. The signal number measured by AE were rather smaller than the number of fragments measured by optical method, since some fiber fracture signals were lost while AE detection. However, one-to-one correspondence between the x-position location by AE and real break positions by optical method was generally established well. The fiber break source location using AE can be a valuable method to measure IFSS for semi- or nontransparent matrix composites nondestructively (NDT).

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.1180-1184
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• 2001

This paper presents the effect of air gap insertion on the results in measuring the transmission loss of sound barrier by using APAMAT. The measured results show that air gap insertion improves transmission loss as by two-room method or intensity method. The measured results are compared with the predicted transmission loss using MATLAB GUI program based on the transfer matrix method. Predicted results were found to be in reasonable agreement with measured results.

• Proceedings of the KSR Conference
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• 2002.10b
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• pp.1086-1093
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• 2002

In Korea mid chord offset method has been used to measure the track irregularities. This method has been also used all over the world widely because of its accessibility and the operational excellence for measured data. But it has been pointed out recently that track irregularities reconstructed from measured data have unexpected noise in the high frequency area as the defect of this way. This study shows the cause of noise which occurs during reconstructing process and mentions the solutions briefly.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.4
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• pp.204-208
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• 2006

This study is to describe continuous-flow analysis (CFA) for the determination of nitrate using hydrazine-copper in plant material and to test precision of this method compared with that of methods, which are RQflex method and salicylic acid method. Samples were leaves of watermelon, cucumber, melon and tomato. Nitrate values measured by the RQflex method were greater than those measured by CFA or salicylic acid method. The correlation of nitrate values between those measured by CFA and salicylic acid method was $R^2=0.9671$, and those measured by CFA between those measured by RQflex method was $R^2=0.9739$. Recovery rate of nitrate added to tissue extract by CFA method was $99.7{\pm}0.25%$.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.718-722
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• 2014

A method for estimating the cylindrical shape of a sound radiator is presented. It assumes that sound field can be measured by a linear array. A sound field, due to the radiator vibrating with uniform velocity, can be determined by its shape, size, and orientations. Measured data also can be varying from the array's position. To predict the shape of radiators from these measured data, mathematical relation between geometric parameter and measured information is needed. Assume that a radiator is cylinder, the magnitude and phase of measured pressure is related with the length and diameter of radiator, respectively. In this paper, the method for estimating length and shape of a finite cylinder by using its radiated pressure is proposed and verified through experiment.

• Korean Journal of Optics and Photonics
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• v.22 no.4
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• pp.161-169
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• 2011

In this paper, a tolerance allocation method using Monte-Carlo simulation with measured reflective eccentricity for high-sensitive IR optics is proposed. During optics fabrication and alignment, reflective eccentricity was measured using an optical centration measurement instrument. A Monte-Carlo simulation was performed using measured eccentricity data, and it gives statistical estimated performance of the optics after fabrication. The validity of the proposed tolerance allocation method was verified comparing the estimated MTF result with the measured MTF result of the fabricated optics.