• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.342-348
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• 2002

This paper presents a computer image processing system, which measures the thickness of the ALC block and inspects the defect on a real-time basis. The Image processing system was established with a CCD camera, an image grabber, and a personal computer without using assembled measurement equipment. The image obtained by the system was analyzed by a devised algorithm, specially designed for the enhanced measurement accuracy. For the realization of proposed algorithm, the pre-processing method that can be applied to overcome uneven lighting environment, and threshold decision method, and subpixel method are developed. from the experimental results, we could find that the required measurement accuracy specification is sufficiently satisfied using our proposed method.

• Journal of Surface Science and Engineering
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• v.29 no.6
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• pp.660-665
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• 1996

Thin films of indium oxide and indium tin oxide have been prepared by d.c. magnetron sputtering onto the fused silica substrates kept at 90, 200 and $300^{\circ}C$. In order to elucidate the optical absorption process in low energy region below 3 eV, we have analyzed the absorption coefficients obtained from reflectance and transmittance measurements for these films based on the Lucovsky model. It has been found for the first time that a defect center in the band gap is located at 0.8~1.4 eV below the Fermi level in all films and arises from oxygen vacancies in their films. The optical absorption in low energy region is explained to be dominated by the transition of electrons trapped at the positively charged (+2e) oxygen vacancies with s-like nature to the conduction band formed from the 5s-orbit in indium atoms.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.277-278
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• 1998

CT/MRI images were frequently taken to evaluate the anatomic structure and disease status, and to plan the treatment modality for oral and maxillofacial surgery. However, surgeons have many difficulties in reading and understanding 2D images without long time experiences. This study presents the method of 3D reconstruction with fine CT slices and its clinical application. We applied this method a clinical patient with oral and maxillofacial trauma and produced 3D reconstructed model which shows the fracture line in panfacial area and bone defect.

• International Journal of Korean Welding Society
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• v.1 no.1
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• pp.7-12
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• 2001

Real time monitoring has become critical as the use of laser welding increases. Plasma and spatter are measured and used as the signal for estimating weld quality. The estimating algorithm was made using the fuzzy pattern recognition with the area of data that is beyond the tolerance boundary. Also, an algorithm that detects the spatter and the localized defect was created in order to kd the partially produced pit and the sudden loss of weld penetration. These algorithms were used in quality monitoring of the $CO_2$ laser tailored blank weld. Statistical program that can display the laser weld quality result and the signal transition was made for the first stage of the remote control system.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.5
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• pp.33-39
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• 1995

This paper presents a method of detecting localized defects on tapered roller bearing in main spindle of machine tool system. The statistical parameters in time-domain processing technique have been calculated to extract useful features from bearing vibration signals. These features are used by the input feature of an artificial neural network to detect and diagnose bearing defects. As a results, the detection of bearing defect conditions could be successfully performed by using an artificial neural network with statistical parameters of acceleration signals.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.6
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• pp.650-655
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• 2011

Analysis of two-dimensional Rayleigh wave scattering pattern by a surface defect is studied through modified boundary element method. BEM proposed in this paper has special treatment at each end of boundary which should have the Rayleigh wave go away without any generation of virtual reflections. It is shown that treatment for truncated boundary which is used to model two-dimensional Rayleigh waves' behavior in an elastic half-space is successfully implemented. To check numerical results' accuracy, time domain IFFT signal of the displacements is presented. Improvement on getting rid of unwanted influence of truncated boundary induced by 2-D Rayleigh waves on a flat surface of an elastic half-infinite medium is shown. As a final goal, the numerical results of Rayleigh wave scattering trend are plotted and they are compared with theoretical curves to prove its accuracy.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2402-2404
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• 1999

In this study, we measured the PD pattern with multiple voids in PET film. The analysis of PD pattern was employed the statistical factor such like CCF(cross correlation factor), asymmetry, kurtosis and etc. The difference of PD patterns caused by arrangement of voids, even if the same size and numbers of void in PET film. Such result of experiment will be used to know the PD source in the real equipment about arrangement and numbers of the defect in insulator.

• Journal of the Semiconductor & Display Technology
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• v.16 no.1
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• pp.112-115
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• 2017

ITO thin films were grown on the glass substrate under various oxygen gas flow and substrate temperature by using FTS (Facing Target Sputtering) system. To investigate properties of as-prepared films for transparent electrical devices, we employed four-point probe, UV-VIS spectrometer, X-ray diffractometer (XRD), scanning electron microscopy (SEM), Hall Effect measurement system and Atomic Force Microscope (AFM). As a results, all of prepared samples has high transmittance of over 80 % in the visible range (300-800 nm). Their resistivity increased as a function of oxygen gas flow and substrate temperature due to their crystal structure and oxygen defect in the films. As-prepared films have a resistivity of under $10^{-4}({\Omega}-cm)$.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.267-267
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• 2013

Band engineering of a nanowire is related to the question what is the minimum size of a nanowire-based device. At the subnanometer scale, there has been a long standing problem whether it is possible to both control an energy band of an isolated nanowire by a dopant and measure it using angle-resolved photoemission spectroscopy (ARPES). This is because an extra atom in the subnanometer wire plays as a defect rather than a dopant and it is challenging to assemble isolated subnanometer wires into an array for an ARPES measurement. We demonstrate that only one of multiple metallic subnanometer wires canbe controlled electronically by a dopant maintaining the whole metallic bands of other wires, which was observed directly by ARPES. Here,the multiple metallic subnanometer wires were produced on a stepped Si(111) surface by a self-assembly method. The selective band engineering proves that the selectively-controlled metallic wire is nearly isolated electronically from other metallic wires and an electronic structure controlcan be realized down to subnanometer scale.

• Journal of Surface Science and Engineering
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• v.37 no.3
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• pp.175-178
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• 2004

The size and number of nano-size defects of thin trivalent chrome layers were determined by small angle neutron scattering (SANS) without breaking the thin chrome layers. Most of defect size of the trivalent chromium prepared in this test conditions is in the range of about 40nm. The number of nano-size defects less than about 40nm of the trivalent chromium layer increases with plating voltage at constant current density From this study, SANS is proved as one of useful techniques to evaluate nano-size defects of thin film layer.