• 반도체디스플레이기술학회지
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• 제18권1호
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• pp.5-9
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• 2019

Optical emission spectroscopy is used to identify chemical species and monitor the changes of process results during the plasma process. However, plasma process monitoring or fault detection by using emission signal variation monitoring is vulnerable to background signal fluctuations. IR heaters are used in semiconductor manufacturing chambers where high temperature uniformity and fast response are required. During the process, the IR lamp output fluctuates to maintain a stable process temperature. This IR signal fluctuation reacts as a background signal fluctuation to the spectrometer. In this research, we evaluate the effect of infrared background signal fluctuation on plasma process monitoring and improve the plasma process monitoring accuracy by using simple infrared background signal subtraction method. The effect of infrared background signal fluctuation on plasma process monitoring was evaluated on $SiO_2$ PECVD process. Comparing the $SiO_2$ film thickness and the measured emission line intensity from the by-product molecules, the effect of infrared background signal on plasma process monitoring and the necessity of background signal subtraction method were confirmed.

• 한국신뢰성학회지:신뢰성응용연구
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• 제18권2호
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• pp.153-160
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• 2018

Purpose: A traffic signal controller needs to control and coordinate to ensure that traffic and pedestrians move as smoothly as possible. Since a traffic signal controller has a significant impact on the safety of vehicles and pedestrians, it is important to monitor the failure and deterioration of the traffic signal controller. The purpose of this paper is to propose an IoT (Internet of Things)-based monitoring system for a traffic signal controller. Methods: Every traffic signal controller has a nominal system trajectory specified when it is deployed. The proposed IoT-based monitoring system collects the system trajectory information through real-time monitoring. By comparing the nominal system trajectory and the monitored system trajectory, we are able to detect the failure and deterioration of the traffic signal controller. Conclusion: The proposed IoT-based monitoring system can contribute to the safety of vehicles and pedestrians by maximizing the availability of a traffic signal controller.

• 소성∙가공
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• 제18권2호
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• pp.144-149
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• 2009

Recently, the monitoring technology of machining process is very important to improve productivity and quality in manufacturing filed. Such monitoring technology has been performed to measurement using vibration signal, acoustic emission signal and tool dynamometer. However, micro machining is limited small-scale parts machining because micro tool is very small and weakness to generate signal in micro machining process. Therefore, this study has efficient sensing technology for real monitoring system in micro machine that is proposed to supplement a disadvantage of single-sensor by multi sensor. From experimental result, it was evaluated tool wear and cutting situation according to repetitive slot cutting condition and changing cutting condition, and it was performed monitoring spindle rpm and condition according to compare acceleration signal with current signal.

• 대한설비관리학회지
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• 제23권4호
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• pp.21-27
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• 2018

This paper proposed the real-time monitoring methodology of a traffic signal controller. The proposed methodology is based on the simulation technology, and it is necessary to construct a simulation model imitating the behavior of a traffic signal controller. By executing the simulation model, we can obtain the 'nominal system trajectory' of the traffic signal controller. On the other hand, an IoT(Internet of Things)-based monitoring device is implemented in a traffic signal controller. Through the monitoring device, it is possible to obtain the 'actual system trajectory'. By comparing the nominal system trajectory and the actual system trajectory, we can estimate the degree of deterioration of a traffic signal controller.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 춘계학술대회 논문집
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• pp.30-34
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• 1998

In-process monitoring of cutting conditions and tool wear is important for improving productivity. This paper is concerned with on-line monitoring of tool wear and cutting force in end milling operation. The experimental study deals with the relations between flank wear and cutting force signal. Tool wear is detected by monitoring of cutting signal. A monitoring procedure is shown in this paper. The influence of flank wear on cutting signal activity was examined. The results are presented in the form of graphs. The analysis of the cutting signal and flank wear curves provides useful indicators of unacceptable wear development in the tool.

• 터널과지하공간
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• 제30권1호
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• pp.1-14
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• 2020

미소진동 모니터링은 구조물의 미세 수준의 손상을 감지하여 구조물의 성능확인 및 안전관리에 활용된다. 신뢰도 높은 미소진동 모니터링 시스템을 구성하기 위해서는 수집된 신호를 변환하는 시그널 컨디셔너의 역할이 매우 중요하다. 시그널 컨디셔너는 정확한 데이터 수집과 기기 정밀 제어에 도움을 주며 신호변환, 선형화, 증폭 등의 추가적인 기능을 수행한다. 본 기술보고는 기존에 개발한 미소진동 모니터링 시스템의 성능을 향상하여 보다 정밀한 모니터링 구현을 목적으로 광산현장에 적합한 노이즈 저감형 시그널 컨디셔너를 개발하고 이를 검토하였다.

• ETRI Journal
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• 제30권3호
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• pp.461-468
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• 2008

This paper presents a chromatic dispersion monitoring technique using a clock-frequency component for carrier-suppressed return-to-zero (CSRZ) signal. The clock-frequency component is extracted by a clock-extraction (CE) process. To discover which CE methods are most efficient for dispersion monitoring, we evaluate the monitoring performance of each extracted clock signal. We also evaluate the monitoring ability to detect the optimum amount of dispersion compensation when optical nonlinearity exists, since it is more important in nonlinear transmission systems. We demonstrate efficient CE methods of CSRZ signal to monitor chromatic dispersion for optimum compensation in high-speed optical communication systems.

• 융합신호처리학회논문지
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• 제11권3호
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• pp.197-202
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• 2010

본 논문에서는 가정 내에서 보다 편리하게 건강모니터링을 수행하기위한 홈헬스케어용 다중생체 계측시스템을 구현하였다. 측정대상 신호는 가정 내에서 일반인들이 쉽게 측정할 수 있으며 많은 건강정보를 포함하고 있는 심전도, 맥파 그리고 체온을 대상으로 하였다. 구현된 생체계측 시스템은 신호검출을 위한 센서부, 각각의 생체신호를 증폭 및 필터링하기 위한 아날로그 신호처리부, 아날로그신호를 디지털로 변환하여 처리하고 시스템 주변장치를 제어하기위한 시스템제어부 및 모니터링 프로그램으로 구성되었다. 구현된 시스템은 시스템자체에서의 디스플레이뿐만 아니라 블루투스무선통신을 통해 홈서버용 PC 또는 웹을 통해 원격모니터링이 가능하여 원격건강정보 모니터링에 활용이 가능하다. 구현된 생체신호 계측시스템의 성능평가 결과 실제 홈 헬스케어에 적용 가능성을 확인하였다.

• 대한의용생체공학회:의공학회지
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• 제16권3호
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• pp.317-324
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• 1995

A need exists for the accurate identification of time series models having time varying parameters, as is important in the case of real time identification of nonstationary EMG signal. Thls paper describes real time identification and muscle fatigue monitoring method of nonstationary EMG signal. The method is composed of the efficient identifier which estimates the autoregressive parameters of nonstationary EMG signal model, and its real time implementation by using T805 parallel processing computer. The method is verified through experiment with real EMG signals which are obtained from surface electrode. As a result, the proposed method provides a new approach for real time Implementation of muscle fatigue monitoring and the execution time is 0.894ms/sample for 1024Hz EMG signal.

• International Journal of Internet, Broadcasting and Communication
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• 제11권2호
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• pp.27-30
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• 2019

Factory monitoring systems are gaining importance in wide areas of industry. Especially, there have been many efforts in implementation of vibration measurement and analysis for monitoring the status of rotating machines. In this paper, a digital signal processor (DSP) based monitoring system dedicated to the vibration monitoring and analysis on rotating machines is discussed. Vibration signals are acquired and processed for the continuous monitoring of the machine status. Time domain signals and fast Fourier transform (FFT) are used for vibration analysis. All of the signal processing procedures are done in the DSP to reduce the production and maintenance cost. The developed system could also provide remote and mobile monitoring capabilities to operator via internet connection. This paper describes the overview of the functional blocks of the implemented system. Test results based on signals from small-size single phase motors are discussed for monitoring and defect diagnosis of the machine status.