• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.5
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• pp.307-311
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• 2016

Although there are existing Residual Current Protective Device (RCD) including detect electric leakage and elements such as short circuit and surge, the occurrence of incidents caused by electric faults, including fire, are still constant. The purpose of this study is to analyze the causes of accidents through the electric field distribution in the interpretation of the fault contact breaker. Simulation results by the arc fault has shown the convergence of temperature and electric field to the defect. Through their simulation results, the main cause of erosion phenomena in circuit breaker bar is the electric arc by concentration of electric field not due to dissolve by temperature.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.7
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• pp.387-393
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• 2016

Threshold voltage shift has been observed from many thin-film transistors (TFTs) and the time evolution of the shift can be modeled as the stretched-exponential and -hyperbola function. These analytic models are derived from the kinetic equation for defect-creation or charge-trapping and the equation consists of only reversible reactions. In reality TFT's a shift is permanent due to an irreversible reaction and, as a result, it is reasonable to consider that both reversible and irreversible reactions exist in a TFT. In this paper the case when both reactions exist in parallel and make a combined threshold voltage shift is modeled and simulated. The results show that a combined threshold voltage shift observed from a TFT may agrees with the analytic models and, thus, the analytic models don't guarantee whether the cause of the shift is defection-creation or charge-trapping.

• Journal of the Korean Institute of Gas
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• v.16 no.1
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• pp.22-25
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• 2012

Welding and/or fusion in polyethylene(PE) system made on site is focused on the control of the welding or fusion process to follow proper procedure. The process control is important, but it is not sufficient for the long term reliability of a pipe system. To achieve the rate of failure close to zero, Non Destructive Testing(NDT) is necessary in addition to joining process control. For electrofusion joints several non-destructive testing methods are available. The ultrasonic phased array technique is possible to detect various defects including wire deviations and regions with lack of fusion. In this studies, testing was carried to detect the defect after electrofusion joining of polyethylene piping is utilized by the ultrasonic phased array technique. From testing data, ultrasonic phased array technique is recommended as a reliable non-destructive testing method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.12
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• pp.1710-1715
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• 2014

In this paper, we propose a novel on-chip test logic for TSV fault detection in 3-dimensional integrated circuits. The proposed logic called OTT realizes the input signal delay-based TSV test method introduced earlier. OTT only includes one F/F, two MUXs, and some additional logic for signal delay. Thus, it requires small silicon area suitable for TSV testing. Both pre-bond and post-bond TSV tests are able to use OTT for short or open fault as well as small delay fault detection.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.818-823
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• 2003

본 논문에서는 입력 매칭(input matching) BIST(Built-In Self-Test) 회로를 이용한 RF font end의 새로운 결함 검사방법을 제안한다. BIST 회로를 가진 RF front end는 1.8GHz LNA(Low Noise Amplifier: 저 잡음 증폭기)와 이중 대칭 구조의 Gilbert 셀 믹서로 구성되어 있으며, TSMC 0.25$\mu\textrm{m}$ CMOS 기술을 이용하여 설계되었다. catastrophic 결함 및 parametric 변동을 가진 RF front end와 결함을 갖지 않은 RF front end를 판별하기 위해 RF front end의 입력 전압 특성을 조사하였다. 본 방법에서는 DUT(Device Under Test: 검사대상이 되는 소자)와 BIST 회로가 동일한 칩 상에 설계되어 있기 때문에 측정할 때 단지 디지털 전자계와 고주파 전압 발생기만이 필요하며, 측정이 간단하고 비용이 저렴하다는 장점이 있다. BIST 회로가 차지하는 면적은 RF front end가 차지하는 전체면적의 약 10%에 불과하다. 본 논문에서 제안하는 검사기술을 이용하여 시뮬레이션해 본 결과 catastrophic 결함에 대해서는 100%, parametric 변동에 대해서는 약 79%의 결함을 검출할 수 있었다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.4
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• pp.83-90
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• 2018

In this research, we developed a process design hot-forging technology that precisely forms an inner race. The inner race transmits power to a one-way clutch of an automatic transmission and minimizes the CNC machining allowance. For a multi-stage hollow shape (inner race), we proposed several shapes of blocker and finisher for the precision hot-forging process and analyzed the forging process using DEFORM. The hot-forging process was optimized for several parameters, such as metal flow pattern, forging defect, and forming load. Blockers and finisher dies in the hot-forging process were designed to select optimal shapes from finite element analysis, and experiments were conducted to optimize the hot-forging process.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.892-894
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• 2013

Edge has been utilized in various application fields with development of technique of digital image processing. In conventional edge detection methods, there are some methods using mask including Sobel, Prewitt, Roberts and Laplacian operator. Those methods are that implement is simple but generates errors of edge detection in images added AWGN(additive white Gaussian noise). Therefore, to compensate the defect of those methods, in this paper, an edge detection algorithm using modified mask is proposed, and it showed superior edge detection property in AWGN.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.404-406
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• 2013

An image edge has been utilized as preprocessing procedure in various field such as object detection, object recognition. there are Sobel, Prewitt, Roberts, Laplacian as conventional edge detection methods. existing methods are implement is simple, but edge detection characteristics is insufficient in impulse noise area. Therefore, to compensate the defect of conventional methods, in this paper, an edge detection algorithm using modified mask is proposed.

• Journal of Korea Foundry Society
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• v.20 no.6
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• pp.368-376
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• 2000

Rheology forming technology has been accepted as a new method for fabricating near net shaped products with lightweight aluminum alloys. The rheology forming process consists of reheating process of billet, billet handling, filling into the die cavity and solidification of rheology formed part. The rheology forming experiments are performed with two different die temperatures ($T_d$ = $200^{\circ}C$, $300^{\circ}C$) and orifice gate type. The filling behavior and various defects of Al-Si materials with wear resistance (A357, A390 and ALTHIX 86S) fabricated in rheology forming process are evaluated in terms of alloying elements and surface non-uniformity. Finally, the methods to obtain the rheology formed products with high quality are described by solutions for avoiding the surface and internal defects.

• Journal of Korean Society for Quality Management
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• v.38 no.3
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• pp.425-438
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• 2010

This study investigates what effects employment flexibility have on the business performance in the computer programming, system consultancy and related services. An analysis of the effects of employment flexibility on outcomes of human resource management revealed that companies which had a higher proportion of temporary agency workers and adjusted employment more frequently had higher turnover rates. The study also showed that the higher the proportion of non-regular workers, outsourcing and the easier it was to adjust working hours, the higher the absence rate. Meanwhile, companies that made employment adjustments more often showed higher defect rates and lower customer satisfaction. It was also found that in companies with a higher proportion of outsourcing and higher possibility of employment adjustments, workers were less interested in new technologies.