• Nuclear Engineering and Technology
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• 제53권1호
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• pp.294-303
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• 2021

Various types of sensors are used at industrial sites to measure vibration. With the increase in the diversity of vibration measurement methods, vibration monitoring methods using camera equipment have recently been introduced. However, owing to the physical limitations of the hardware, the measurement resolution is lower than that of conventional sensors, and real-time processing is difficult because of extensive image processing. As a result, most such methods in practice only monitor status trends. To address these disadvantages, a high-resolution vibration measurement method using image analysis of the edge region of the structure has been reported. While this method exhibits higher resolution than the existing vibration measurement technique using a camera, it requires significant amount of computation. In this study, a method is proposed for rapidly processing considerable amount of image data acquired from vision equipment, and measuring the vibration of structures with high resolution. The method is then verified through experiments. It was shown that the proposed method can fast measure vibrations of structures remotely.

• 전기학회논문지
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• 제58권10호
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• pp.2071-2078
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• 2009

In this paper, we proposed a non-contact respiration measurement system with ultrasonic proximity sensor. Ultrasonic proximity sensor approach of respiration measurement which respiration signatures and rates can be derived in real-time for long-term monitoring is presented. 240 kHz ultrasonic sensor has been applied for the proposed measurement system. The time of flight of sound wave between the transmitted signal and received signal have been used for a respiration measurement from abdominal area. Respiration rates measured with the ultrasonic proximity sensor were compared with those measured with standard techniques on 5 human subjects. Accurate measurement of respiration rate is shown from the 50 cm measurement distance. The data from the method comparison study is used to confirm the performance of the proposed measurement system. The current version of respiratory rate detection system using ultrasonic can successfully measure respiration rate. The proposed measurement method could be used for monitoring unconscious persons from a relatively close range, avoiding the need to apply electrodes or other sensors in the correct position and to wire the subject to the monitor. Monitoring respiration using ultrasonic sensor offers a promising possibility of non-contact measurement of respiration rates. Especially, this technology offers a potentially inexpensive implementation that could extend applications to consumer home-healthcare and mobile-healthcare products. Further advances in the sensor design, system design and signal processing can increase the range of the measurement and quality of the rate-finding for broadening the potential application areas of this technology.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2005년도 공동학술대회 논문집
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• pp.71-76
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• 2005

이 논문에서는 수리시설물을 효율적으로 유지관리하기 위하여 저수지 및 방조제제체에 계측 시스템을 설치하고, 전기비저항, SP, 수위, 간극수압 및 지중변위를 주기적으로 모니터링하여 그 결과를 분석함으로써 제체의 누수현상 및 안정성 평가를 시도하였다. 저수지 및 방조제의 체제에 설치된 전기비저항/SP 측정 시스템으로부터 측정한 각 단계별 측정 자료의 변화영상을 구하고, 변화추이를 비교분석함으로써 누수현상을 정확하게 파악할 수 있었고, 수위, 간극수압 및 지중변위량의 자료를 종합적으로 해석함으로써 제체의 안정성을 평가할 수 있었다. 이러한 결과로부터 종래의 일시적으로 실시한 물리탐사 결과로부터 누수현상을 파악하는 것보다 모니터링 계측시스템을 설치하여 운용하는 것이 수리시설물을 효율적이고 경제적으로 유지관리하기 위한 방법임을 알았다.

• 지구물리와물리탐사
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• 제8권2호
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• pp.177-183
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• 2005

이 논문에서는 수리시설물을 효율적으로 유지관리하기 위하여 저수지 제체에 계측 시스템을 설치하고, 전기비저항, 수위, 간극수압 및 지중변위를 주기적으로 모니터링하여 그 결과를 분석함으로써 제체의 누수현상 및 안정성 평가를 시도하였다. 저수지 제체의 댐마루에 설치된 전기비저항 측정 시스템으로부터 측정한 각 단계별 전기비저항의 변화영상을 구하고, 변화추이를 비교분석함으로써 누수현상을 정확하게 파악할 수 있었고, 수위, 간극수압 및 지중변위량의 자료를 종합적으로 해석함으로써 제체의 안정성을 평가할 수 있었다. 이러한 결과로부터 종래의 일시적으로 실시한 전기비저항탐사 결과로부터 누수현상을 파악하는 것보다 전기비저항 등 모니터링 계측시스템을 설치하여 운용하는 것이 수리시설물을 효율적이고 경제적으로 유지관리하기 위한 방법임을 알았다.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2017년도 춘계공동학술대회
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• pp.122-122
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• 2017

Recently, environmental problems have become an area of growing interests. In-situ monitoring of water quality is fundamental to most environmental applications. The accurate measurement of nitrate concentrations is fundamental to understanding biogeochemistry in aquatic ecosystems. Several studies have reported that one of the most feasible methods to measure nitrate concentration is the use of Ion Selective-electrodes (ISEs). The ISE application to water monitoring has several advantages, such as direct measurement methodology, high sensitivity, wide measurement range, low cost, and portability. However, the ISE methods may yield inconsistent results where there was a difference in temperature between the calibration and measurement solutions, which is associated with the temperature dependence of ionic activity coefficients in solution. In this study, to investigate the potential of using the combination of a temperature sensor and nitrate ISEs for minimizing the effect of temperature on real-time nitrate sensing in natural water, a prototype of on-site water monitoring system was built, mainly consisting of a sensor chamber, an array of 3 ISEs, an waterproof temperature sensor, an automatic sampling system, and an arduino MCU board. The analog signals of ISEs were obtained using the second-order Sallen-key filter for performing voltage following, differential amplification, and low pass filtering. The performance test of the developed water nitrate sensing system was conducted in a monitoring station of drinking water located in Jeongseon, Kangwon. A temperature compensation method based on two-point normalization was proposed, which incorporated the determination of temperature coefficient values using regression equations relating solution temperature and electrode signal determined in our previous studies.

• 대한의용생체공학회:의공학회지
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• 제23권5호
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• pp.397-403
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• 2002

뇨당 측정 시스템은 소변 속의 글루코오스 농도를 측정함으로서 당뇨 수치를 모니터링하는 비침습적인 당뇨병 자가 진단 장치이다. 본 논문에서는 기존의 침습형 혈당측정방법의 불편성과 비색계를 이용한 뇨당 검사법의 단점을 보완한 뇨당 측정시스템을 설계하였다. 뇨당 측정시스템은 뇨당 측정용 화학센서, 신호검출부, 디지털 제어 및 신호분석부, 디스플레이부 및 전원부로 구성된다. 뇨당측정용 센서로는 재현성이 뛰어나고 다루기가 간편하며 저렴한 가격으로 대량 생산할 수, 있는 일회용 뇨당측정용 전류화학센서를 개발하였다. 설계한 뇨당 측정시스템의 성능을 평가하기 위하여 사람의 소변에 임의의 농도의 글루코오스 성분을 섞은 용액에 대하여 글루코오스 성분 분석시 사용되는 표준장비와의 비교분석을 통해서 글루코오스 농도 검출에 대한 신뢰성 평가를 수행하였다. 회귀분석에 기초한 신뢰성 평가를 수행한 결과 표준오차는 2.85282로 나타났다. 또한, 화학센서를 사용해서 측정하는 시스템을 평가 시 중요한 파라미터인 S.D(Standard Deviation)는 10%로서 임상적으로 유효한 15% 범주 내에 있음을 확인하였고, C.V(Coefficient of Validation)값은 ,5%이내이므로 혈당센서의 기준으로 평가해 볼때 만족하는 결과를 보였다.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2009년도 추계학술대회 논문집
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• pp.473-474
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• 2009

• 한국소음진동공학회논문집
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• 제15권1호
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• pp.3-11
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• 2005

For monitoring of the civil and building structure, optical fiber sensors are very convenient. The fiber sensors are very small and do not disturb the structural properties. They also have several merits such as electro-magnetic immunity, long signal transmission, good accuracy and multiplexibility in one sensor line. Strain measurement technologies with fiber optic sensors have been investigated as a part of smart structure. In this paper, we investigated the possibilities of fiber optic sensor application to the monitoring of beam-column joints of structures. We expect that the fiber optic sensors replace electrical strain gauges. The commercial electric strain gauges show good stability and dominate the strain measurement market. However, they lack durability and long term stability for continuous monitoring of the structures. In order to apply the strain gauges, we only have to attach them to the surfaces of the structures. In this paper, we investigate the possibility of using fiber optic Bragg grating sensors to joint structure. The sensors show nice response to the structural behavior of the joint.

• Structural Monitoring and Maintenance
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• 제7권1호
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• pp.1-12
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• 2020

Railway tracks are the direct supporting structures of the trains, which are vulnerable to produce large deformation under the temperature stress or subgrade settlement. The health status of track is critical, and the track should be routinely monitored to improve safety, lower the risk of excess deformation and provide reliable maintenance strategy. In this paper, the distributed optical fiber sensor was proposed to monitor the continuous deformation of the track. In order to validate the feasibility of the monitoring method, two deformation monitoring tests on one steel rail model in laboratory and on one real railway tack in outdoor were conducted respectively. In the model test, the working conditions of simply supported beam and continuous beam in the rail model under several concentrated loads were set to simulate different stress conditions of the real rail, respectively. In order to evaluate the monitoring accuracy, one distributed optical fiber sensor and one fiber Bragg grating (FBG) sensor were installed on the lower surface of the rail model, the strain measured by FBG sensor and the strain calculated from FEA were taken as measurement references. The model test results show that the strain measured by distributed optical fiber sensor has a good agreement with those measured by FBG sensor and FEA. In the outdoor test, the real track suffered from displacement and temperature loads. The distributed optical fiber sensor installed on the rail can monitor the corresponding strain and temperature with a good accuracy.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.834-837
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• 2005

In this paper, we describe the method of non-invasive blood pressure measurement using pulse wave transit time(PWTT). PWTT is a new parameter involved with a vascular that can indicate the change of BP. PWTT is measured by continuous monitoring of ECG and pulse wave. No additional sensors or modules are required. In many cases, the change of PWTT correlates with the change of BP. We measure pulse wave using the photo plethysmograph(PPG) sensor in an earlobe and we measure ECG using the ECG monitoring device our made in the chest. The measurement device for detecting pulse wave consists of infrared LED for transmitted light illumination, pin photodiode as light detector, amplifier and filter. We composed 0.5Hz high pass, 60Hz notch and 10Hz low pass filter. ECG measurement device consists of multiplexer, amplifier, filter, micro-controller and RF module. After amplification and filtering, ECG signal and pulse wave is fed through micro-controller. We performed the initial work towards the development of ambulatory BP monitoring system using PWTT. An earlobe is suitable place to measure PPG signal without the restraint in daily work. From the results, we can know that the dependence of PWTT on BP is almost linear and it is possible to monitoring an individual BP continuously after the individual calibration.