• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2004년도 춘계학술대회
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• pp.241-245
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• 2004

In this paper, we implement a portable bioelectric signal measurement system for the safety of industrial workers. The developed system consists of two parts: the one is boielectric signal measurement unit and the other is signal analyzer system with PDA. The former includes signal processing part, A/D convertor, and 8051 based microprocessor, the latter includes software for signal analysis and display. The developed system detects industrial worker's ECG and displays and stores it to PDA. The ECG data in PDA can be transmitted to PC located in a distance, allowing a doctor to review the ECG and make a treatment decision. A doctor analyzes the ECG data and gives medical treatment to industrial worker.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.409-412
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• 2000

A high performance EEG signal measurement system is fabricated. It consists of high precision pre-amplifier and auto identification bandwidth unit. High precision pre-amplifier is composed of signal generator, signal amplifier with a impedance converter, body driver and isolation amplifier. The pre-amplifier is designed for low noise characteristics, high CMRR, high input impedance, high IMRR and safety, Auto identification bandwidth unit is composed of AD-converter and PIC micro-controller for real time processing EEG signal. The performance of EEG signal measurement system has been shown the classified bandwidth through the clinical demonstrations.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.883-886
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• 2005

This paper proposed a wireless measurement system (WMS) for an effective condition monitoring using wireless communication. WMS consists of two parts: transmitter(TM) acquired a dynamic signal from physical system using ICP type accelerometer sensor. An acquired signal modulated through the low/high pass filter and amplifier in DAQ board, which converted to digital signal. Embedded board(E-board) transferred digital signals to base station(BS) through the socket IEEE.802.11.b. BS is adopted IOCP server structure. Because it can acquired signal well during transferred digital signal. Signal processing used LabVIEW Library, BS(server) designed to realize multi-thread using visual C++.NET for 1 many meaning data processing

• 산업경영시스템학회지
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• 제20권41호
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• pp.221-229
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• 1997

This study concerns with the comparing and evaluation for Signal - Noise Ratio of the quantitative signal factors in the measurement devices for developing efficiency for product system. On the basis of this conditions and purpose, this study presents a general procedure for deriving the Signal - Noise Ratio, confidence intervals and significiant testing for the measurement devices.

• 대한의용생체공학회:의공학회지
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• 제16권3호
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• pp.301-308
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• 1995

A high-precision pre-amplifier is designed for general use in EEG measurement system. It consists of signal generator, signal amplifier with a impedance converter, shield driver, body driver, differential amplifier, and isolation amplifier. The combination of minimum use of inaccurate passive components and the appropriate matching of each monolithic amplifiers results in good noise behavior, low leakage current, high CMRR, high input impedance, and high IMRR. The performance of EEG pre-amplifier has been verified by showing the typical EEG pattevn of a nomad person through the clinical experiments.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제4권2호
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• pp.143-152
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• 2000

As muscular contraction is sustained, the Fourier spectrum of the myoelectric signal is shifted toward the lower frequency. This spectral density is associated with muscle fatigue. This paper describes a quantitative measurement method that performs the measurement of localized muscle fatigue by tracking changes of median frequency based on stationary wavelet transform. Applying to the human masseter muscle, the proposed method offers the much information for muscle fatigue, comparing with the conventional FFT-based method for muscle fatigue measurement.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.607-612
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• 2000

Roundness measurement method using three displacement sensors makes in-process roundness measurement possible on the NC machine because it eliminates the vibration signal and eccentricity signal from measured roundness signal from the workpiece. But if measured signals contain noises, high precision measurement of the roundness isn't possible. In this study, a high precision in-process roundness measurement system is developed, which applies a Kalman filter to the roundness measurement method using three displacement sensors and can be used to measure vibration of the spindle.

• 대한산업공학회지
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• 제30권2호
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• pp.84-92
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• 2004

A process control procedure is proposed when 100% inspection is performed in a process with excellent capability. Only the incomplete measurement data is assumed to be available, i.e. the specific measurement value of the quality characteristic is not available for each item but it can be determined to be smaller or larger than any prescribed value. In the suggested model, a signal limit is introduced to determine whether the process under study is in control or not. If the quality characteristic of an incoming item exceeds the upper signal or the lower signal limit, the process is determined to be stopped or not by comparing the number of consecutively accepted items with a predetermined threshold number. The procedure is designed based on the type I and II errors. The performance of the model is evaluated by the expected number of items produced under the in-control and out-of-control states until the process is stopped.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제32회 KOSCO SYMPOSIUM 논문집
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• pp.157-163
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• 2006

A new technique utilizing LII signal for the measurement of flow velocities of laminar diffusion flames has been investigated. Soot particles in ethylene diffusion flames are heated by a modulated Ar-ion laser beam. LII signals and their phase angles are measured using a lock-in amplifier at the different flame heights and the axial flow velocity are obtained from the measured phase angle delay. The measured velocities are similar to those from LDV measurements under the same operating conditions. The effects of laser power, LII signal wavelength, and modulation frequency are not sensitive to the velocity measurement. However, the choice of an optical chopper blade type could affect the measurement result. The use of a 6/5 chopper blade showed the better result that is possibly due to the square shape of modulated laser beam. This study successfully demonstrated that axial flow velocities of laminar diffusion flames can be measured by a new technique utilizing LII signal, which does not need particle seeding unlikely to LDV or PIV techniques.

• 비파괴검사학회지
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• 제36권2호
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• pp.138-148
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• 2016

Measurement of elastic constants is crucial for engineering aspects of predicting the behavior of materials under load as well as structural health monitoring of material degradation. Ultrasonic velocity measurement for material properties has been broadly used as a nondestructive evaluation method for material characterization. In particular, pulse-echo method has been extensively utilized as it is not only simple but also effective when only one side of the inspected objects is accessible. However, the conventional technique in this approach measures longitudinal and shear waves individually to obtain their velocities. This produces a set of two data for each measurement. This paper proposes a simultaneous sensing system of longitudinal waves and shear waves for elastic constant measurement. The proposed system senses both these waves simultaneously as a single overlapped signal, which is then analyzed to calculate both the ultrasonic velocities for obtaining elastic constants. Therefore, this system requires just half the number of data to obtain elastic constants compared to the conventional individual measurement. The results of the proposed simultaneous measurement had smaller standard deviations than those in the individual measurement. These results validate that the proposed approach improves the efficiency and reliability of ultrasonic elastic constant measurement by reducing the complexity of the measurement system, its operating procedures, and the number of data.