• 대한한의진단학회지
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• 제12권2호
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• pp.8-17
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• 2008

Objectives: For the traditional pulse diagnosis in Oriental Medicine, not only the pulse shape in time domain, but the width, length and depth of arterial pulse also should be measured. However, conventional pulse diagnostic systems have failed to measure the spatial parameters of the arterial pulse e.g. effective length of arterial pulse in the wrist. In fact, there are many ways to measure that kind of spatial features in arterial pulsation, but among them, the method using image sensor provides relatively cheap and simple way, therefore I tested feasibility of measuring 2-dimensional pressure distribution by imaging devices. Methods: Using widely used PC cameras and dotted balloons, the subtle oscillation of skin over the radial artery was recorded continuously, and then the displacement of every dot was calculated. Consequently, the time course of that displacements shows arterial pulse wave. Results: By the proposed method I could get pressure distribution map with 30Hz sampling rate, 21steps quantization resolution, and approximately 1mm spatial resolution. With reduced quantization resolution, $3cm{\times}4cm$ view angle could be achieved. Conclusion: Although this method has some limitations, it would be useful method for detecting 2-dimensional features of arterial pulse, and accordingly, this method provides a novel way to detect 'narrow pulse', 'wide pulse', 'long pulse', 'short pulse', and their derivatives.

• 한국자기학회지
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• 제12권6호
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• pp.206-211
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• 2002

본 연구에서는 3개의 펄스자기장발생 장치와 3-축의 탐지코일을 이용하여 3차원 좌표를 비접촉으로 측정할 수 있는 장치를 제작하였다. 펄스자기장을 만들어 주기 위하여 환 계수기와 아날로그 곱셈기를 사용하여 원하는 한 주기의 파형을 자기장발생장치의 각 축에서 만들어 질 수 있도록 하였다. 그리고 발생된 자기장 값을 거리 r에서 측정하기 위해 탐지코일에 유도된 전압을 증폭시키고 S/H증폭기로 최대 값을 측정하였다. 자기장발생 장치로부터 거리를 0.5m에서 1.5m까지 1차원과 2차원 상에서 탐지코일을 움직여 간을 측정하고 이를 거리로 환산하는 계산식에 의한 결과가 실제 거리의 값과 그 편차가 $\pm$0.5%에서 그 위치를 측정할 수 있음을 알 수 있었다.

• 한국인터넷방송통신학회논문지
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• 제15권1호
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• pp.179-186
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• 2015

본 논문에서는 탐지영역에 존재하는 이동 표적의 유무 정보만을 제공하는 USN(Ubiquitous Sensor Network) 기반 PDR(Pulse Doppler Radar) 센서 노드 환경에서 인접한 PDR 센서로 부터 이동하는 표적의 경로에 따른 검출 시간차의 통계적 특성을 이용한 표적 경로 검출 알고리즘을 제안한다. 알고리즘에 사용된 변수는 실측 실험정보를 기반으로 도출한 표적 검출 시간차와 비검출 시간차이다. 그리고 PDR 센서 탐지 영역에서 발생되는 표적 이동경로는 센서를 관통하는 경로, 센서와 병렬로 이동하는 경로 그리고 두 센서 사이를 바라보고 진입한 후 한쪽 센서 방향으로 향하는 3가지 경우이고, 각 경우에 대해 500회의 실험을 수행 하였다. 그 결과 각 경우에 따른 오류 검출 백분율은 각각 5.67%, 5.83% 그리고 7.17% 으로 제한된 표적 검출 환경에서 정확하게 표적 경로를 검출한다.

• 센서학회지
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• 제25권1호
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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.

• 한국자기학회지
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• 제22권5호
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• pp.178-182
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• 2012

영구자석과 반도체 홀센서가 구비된 집게형 맥진기로 얻은 맥진파형에 고속 푸리에변환(FFT)을 적용하여 생체신호인 호흡수를 추출하였다. 추출된 호흡수는 맥진파형의 형태가 항상 변화하는 요인에 의존하는 심장의 운동에 대한 오차까지 고려하였다. 인위적인 호흡수 템포 15, 20, 30, 40, 50에 각각 측정한 맥진파형의 FFT 스펙트럼에서 피크값과 일치하는 주파수 0.125 Hz, 0.16 Hz, 0.25 Hz, 0.33 Hz, 0.41 Hz와 일치하였다. 100 s, 200 s, 300 s 동안 얻은 맥진파형 데이터에서 호흡성분 추출 알고리즘을 적용한 결과, 시간이 긴 300 s에서 FFT 스펙트럼 피크가 가장 크게 뾰쪽해지는 결과를 얻었다. 집게형 맥진기가 인체의 물리적인 영향을 주는 호흡수를 추출해 내는데 유용한 기기임을 확인하였다.

• 한국자기학회지
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• 제23권4호
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• pp.135-143
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• 2013

요골 동맥의 중앙 부에 위치 한 "관"이란 곳에 영구자석 부착하여 맥의 움직임에 따라 발생하는 자기장의 변화를 홀센서로 정량화하여 맥진파형을 측정하는 집게형 맥진기를 개발하였다. 홀소자 맥진센서로 얻어진 전기적 신호로 심전도와 용적맥파계를 사용해 동시에 측정된 맥박수, 비침습적 혈압, 호흡수, 맥파전달속도와 공간맥파전달속도를 환자감시장치에 디스플레이하였다. 개발된 장치는 한방과 양방의 의료용 저장 매체와 새롭게 시도되거나 융합되어지고 있는 환자감시 장비 및 유비쿼터스 헬스케어 시스템 개발에 도움이 될 것이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.132-135
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• 2008

This paper presents a PLL(Phase Lock Loop) control method for speed control of high speed miniature BLDCM(Brushless DC Motor) using hall sensor. The Proposed PLL based speed control method uses a only phase shift between reference pulse signal according to speed reference and actual pulse signal from hall sensor. It doesn't use any speed calculation, and calculates a direct current reference from phase shift. The current reference is changed to reduce the phase shift between reference and actual pulse. So the actual speed can keep the reference speed. The proposed control scheme is very simple but effective speed control is possible.

• 센서학회지
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• 제24권3호
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• pp.145-150
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• 2015

We introduce a new method of time-division visible light communication (VLC) using LED lamp light for the generation of synchronizing pulses. The LED lamp, driven by an AC 220-V power line, radiates light that has a 120-Hz frequency component. The pulse generator in each VLC system receives the LED lamp light and generates the synchronizing pulses that are required for time-division transmission of multiple VLC channels. The pulse period is subdivided into several time slots for VLC channels. In experiments, 120-Hz synchronizing pulses were generated using LED lamp light, and three VLC channels were transmitted independently without interfering with each other in a condition where the VLC signals overlapped in space. This configuration is useful in constructing multiple wireless sensor networks that are safe and without interference in locations where LED lamps are used for illumination.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표대회 논문집(III)
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• pp.725-730
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• 1998

Recently, non-destructive tests are getting popular in evaluating concrete properties without braking specimens. Among several NDT methods, P-wave velocity measurement technique has been widely used to evaluate the stiffness and strength of concrete. The purpose of this study is to investigate factors influencing P-wave velocity measured by impact-resonant method and ultrasonic pulse velocity method, such as moisture content of concrete, existence and size of coarse aggregates, sensor and sampling rate. Test results show that rod-wave velocity measured by impact-resonant method and ultrasonic pulse velocity are significantly affected by the moisture content of concrete, i.e., the lower moisture content, the lower velocity. Moisture content influences rod-wave velocity stronger than ultrasonic pulse velocity. Rod-wave velocity is faster in concrete than in mortar and is also faster in concrete containing small size aggregates. Sensor and sampling rate have little influence on velocity.

• Advances in nano research
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• 제15권2호
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• pp.155-163
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• 2023

Exercise is beneficial to the body in some ways. It is vital for people who have heart problems to perform exercise according to their condition. This paper describes how an Android platform can provide early warnings of fatigue during wushu exercise using Photoplethysmography (PPG) signals. Using the data from a micro-electro-mechanical system (MEMS) gyroscope to detect heart rate, this study contributes an algorithm to determine a user's fatigue during wushu exercise. It sends vibration messages to the user's smartphone device when the heart rate exceeds the limit or is too fast during exercise. The heart rate monitoring system in the app records heart rate data in real-time while exercising. A simple pulse sensor and Android app can be used to monitor heart rate. This plug-in sensor measures heart rate based on photoplethysmography (PPG) signals during exercise. Pulse sensors can be easily inserted into the fingertip of the user. An embedded microcontroller detects the heart rate by connecting a pulse sensor transmitted via Bluetooth to the smartphone. In order to measure the impact of physical activity on heart rate, Wushu System tests are conducted using various factors, such as age, exercise speed, and duration. During testing, the Android app was found to detect heart rate with an accuracy of 95.3% and to warn the user when their heart rate rises to an abnormal level.