• Journal of Welding and Joining
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• v.28 no.4
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• pp.81-86
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• 2010

In resistance spot welding, regardless of the optimal condition, bad weld quality was still produced due to complicated manufacturing processes such as electrode wear, misalignment between the electrode and workpiece, poor part fit-up, and etc.. Therefore, the goal of this study was to measure the process signal which contains weld quality information, and to develop the process fault monitoring system. Welding force signal obtained through variety experimental conditions was analyzed and divided into three categories: good, shunt, and poor fit-up group. And then a monitoring algorithm made up of an artificial neural network that could estimate the process fault of each different category based on pattern was developed.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.287-290
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• 2003

Over the last few years computer based image processing has become more prominent in forensic science. The image quality from many CCTV systems is too poor for facial recognition. but there are other human characteristics which allow us to recognize individuals from a distance. one of these parameters is a human's height. In this paper, we propose useful height measurement method by auto Position, size adjustment which uses image superimposition and edge detection regardless of lens distortion and not uses conventional photogrammetry calibration methods.

• Journal of Digital Convergence
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• v.10 no.11
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• pp.383-387
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• 2012

Development of automated document management system specified for scanned invoice images suffers from rigorous accuracy requirements for extraction of monetary data, which necessiate automatic validation on the extracted values for a generative invoice table model. Use of certain internal constraints such as "amount = unit price times quantity" is typical implementation. In this paper, we propose a noble invoice information extraction model with improved auto-validation method by utilizing table header detection and column classification.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.639-644
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• 2002

Password typing is the most wifely ued identity verification method in computer security domain. However, due to its simplicity, it is vulnerable to imposter attacks Keystroke dynamics adds a shield to password. Discriminating imposters from owners is a novelty detection problem. Auto-Associative Multilayer Perceptron (AaMLP) has teen proved to be a good novelty detector. However, the wifely used 2-layer AaMLP cannot identify nonlinear boundaries, which can result in serious problems in computer security. In this paper, a nonlinear model, i.e. 4-layer AaMLP, is proposed to serve as the novelty detector, which can remedy the limitations of 2-layer AaMLP.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.345-348
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• 2017

버퍼 오버플로우(Buffer Overflow) 취약점은 시스템 보안에서 아주 중요하다. 본 논문은 바이너리 파일에서 버퍼 오버플로우 취약점을 자동 감지하는 시스템을 제안하였다. 다양한 버퍼 오버플로우 샘플소스를 이용하여 패턴을 만들고, 이렇게 만들어진 패턴을 이용하여 바이너리 파일에서 버퍼 오버플로우 취약점이 포함되어 있는지를 판단한다. 제안한 시스템의 유용성을 위해 실험을 하였고, 어느 정도 의미 있는 결과를 얻을 수 있었다.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.2
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• pp.107-114
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• 2007

This paper describes the Petri Net(PN) model for reliability analysis of fault-tolerant dual Ethernet which Is applied in Naval Combat System. The network for Naval Combat System performs failure detection and auto path recovery by handling redundant path in case of temporary link failure. After studying the behavior of this kind of network, the reliability analysis model is proposed using stochastic Petri Net and continuous-time Markov chains. Finally, the numerical result is analyzed according to changing the failure rate and the recover rate of link.

• Journal of Sensor Science and Technology
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• v.25 no.1
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• pp.71-78
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• 2016

PPG signal measured by pulse oximeter can measure pulse and the oxygen saturation of arterial blood. But the PPG signal is distorted by finger movement or other movement in the body. To detect pulse from the PPG signal with motion artifact, we use band pass filter(BPF), Independent component analysis(ICA) and nonlinear autocorrelation(NAC). BPF is used to remove DC component and high frequency noise in the PPG signal with motion artifacts. ICA is used to separate pulse signal and motion artifact. However, pulse signal separated by ICA have no choice but to accompany signal distortion because pulse signal and motion artifact are not completely independent. So, we use nonlinear autocorrelation to emphasize the pure pulse signal from the distorted signal.

• Journal of the Korean Society of Safety
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• v.12 no.2
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• pp.80-86
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• 1997

In this paper, a temperature controller with monitor function is proposed for the electric furnace system. This controller includes holding and ramp control function, and the control program for the temperature process monitor of the electric furnace. For this purpose, the implementation and performance of auto tuning algorithms in a computer-based controller was studied in relation to the control of nonlinear electric furnace system which is characterized with large delay time. The control program for this controller programmed by c-language. To communicate a control and detection signals, between the controller and the electric furnace is implemented by the I/O data card. We apply the temperature controller to the practical electric furnace. As a result, the proposed controller shows the better status characteristic.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1908-1909
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• 2007

The design of an intelligent toothbrush, capable of monitoring brushing motion, orientation through the grip axis, during toothbrushing is described. Inappropriate Toothbrushing styles, even in adults, sometimes cause dental problems, cavities, gingivitis, etc. This smart system provides user to monitor his or her brushing pattern using accelerometer and magnetic sensors for evaluation of toothbrushing style. Directional information of toothbrush with respect to earth's magnetic field and activity data were measured by a miniaturized low-power micro- controller, MSP430 and transmitted to personal computer by 2.4GHz radio transmitter, nRF2401. A personal computer provides an on-line display of activity and orientation measurements during toothbrushing. The signal trace is then analyzed to extract clinically relevant measurement. This preliminary study showed that the proposed monitoring system was conceived to aid dental care personnel in patient education and instruction in oral hygiene regarding brushing style.

• Proceedings of the KIEE Conference
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• 2006.07e
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• pp.53-54
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• 2006

본 논문에서는 유도전동기의 고정자권선 고장진단을 목적으로 이상적인 전동기의 전류신호와 실시간으로 운전하고 있는 전동기 전류신호를 Park's Vector에 각각 적용시켜 Park's Vector 패턴을 만들고 패턴 피크값의 기준치와 측정치의 편차를 이용하여 오차치를 벗어날 때 고장으로 진단하는 Park's Vector 패턴의 피크값을 이용한 고정자권선의 고장진단을 시도하였다. 숙달된 작업자가 Park's Vector패턴을 보고 고장을 분석해야 했던 방법과는 달리 패턴을 비교하지 않고도 자동으로 고장을 진단하고 경보해주는 진단 방법을 제시하였다. 실제 전류분석 및 진단을 위해 상용 프로그램인 LabVIEW를 이용하였다.