• Tribology and Lubricants
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• 제26권1호
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• pp.73-77
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• 2010

One of the important trends for condition monitoring in the 21st century is the development of smart sensors that will permit the cost-effective continuous monitoring of key machine equipments. In this study, an integrated in-line oil monitoring sensor assigned for continuous in situ monitoring multiple parameters of oil performance is presented. The sensor estimates oil deterioration based on the information about chemical degradation, total contamination, water content of oil and oil temperature. The oil oxidation is estimated by "chromatic ratio", total contamination is measured by the changes in optical density of oil in three optical wave-bands ('Red', 'Green' and 'Blue') and water content is evaluated as relative saturation of oil by water. In order to evaluate the sensor's effectiveness, the sensor was applied to several used oil samples in steel making industry and the results were compared with those measured by standard test methods.

• 한국인공지능학회지
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• 제4권1호
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• pp.8-10
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• 2016

These days, citizens have a lot of ways to get access to IT. In the past, they tended to neglect IT that was thought to be difficult. But, currently, everyone can manufacture and get access not only software but also hardware when he has an idea. Arduino is used. Rinnai had recently released new product named Smart Sensor Range. Safe consumer who gave priority to the safety made new trend gave attention to fire prevention and smart sensor range. The ones who buy gas range prefer safety to economic advantage and/or fire power. The safety system does not always prevent fire accident. This study makes design and produces alarm that perceives temperature of pot when boiling. Not only temperature sensor but also alarm sensor was used to make alarm of boiling water and to give convenient living life. The arduino can be used at practical life to make products for various kinds of people. The invention can give convenience to housewives at kitchen, children and many persons making use of gas range. Another function can be added to develop. This arduino can develop a lot of products by using the study and other designs.

• 문화기술의 융합
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• 제2권4호
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• pp.55-59
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• 2016

본 논문에서는 물 부족, 불균형을 해결하기 위해 우수 이용률을 높이는 방법의 하나로 지하저류조를 설치하여 빗물을 저장하고, 관리하고자 하는 곳을 위한 저류조 수위의 모니터링과 제어에 대한 시스템을 제안하고 이를 구현하였다. 이를 위해 제어를 위한 모듈에는 ATMEL사의 Atmega 128의 마이크로프로세서를 사용하고 수위를 측정할 수 있는 센서는 접촉식 센서의 일종인 부자형태의 레벨센서를 사용하였다. 특히 레벨센서는 출력을 산업체 일반에서 많이 사용하는 크기로 출력하므로 기존의 센서를 대체할 수 있도록 호환성이 높도록 하였다.

• 한국전자통신학회논문지
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• 제17권1호
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• pp.201-206
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• 2022

본 논문은 변기 커버 자동 개폐식 기능을 갖춘 물 내림 시스템을 연구하였다. 커버 위에 부착된 적외선 센서의 감지 여부에 따라 작동하게 된다. 열림 기능의 적외선 센서가 감지 되면 변기 커버의 서보모터를 구동시켜 커버를 올리도록 설정하였고, 닫힘 기능의 적외선 센서가 감지되면 커버를 내리도록 설정하였다. 커버 내부에 기울기 센서를 달아서 커버가 내려가는 것에 동작하도록 설정한 뒤 이것이 작동되면 변기 레버와 연결되어 있는 서보모터가 공급 구의 마개를 열어 물을 내려보내는 방식이다. 또한, 물을 내려보내는 과정 중에서 물이 막혔을 때 알리기 위한 비접촉 수위센서와 LED 기능을 이용해 다음 사용자가 양변기를 이용할 때 겪을 수 있는 불펀을 최소화하였고, 변기가 닫혀있는 동안 세균 증식을 막기 위해 UV-LED 기능도 구현하였다.

• Smart Structures and Systems
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• 제20권1호
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• pp.75-83
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• 2017

Effectively monitoring the concrete cracks is an urgent question to be solved in the structural safety monitoring while cracks in hydraulic concrete structures are ubiquitous. In this paper, two experiments are designed based on the measuring principle of Pulse-Pre pump Brillouin Optical Time Domain Analysis (PPP-BOTDA) utilizing Brillouin optical fiber sensor to monitor concrete cracks. More specifically, "V" shaped optical fiber sensor is proposed to determine the position of the initial crack and the experiment illustrates that the concrete crack position can be located by the mutation position of optical fiber strain. Further, Brillouin distributed optical fiber sensor and preinstall cracks are set at different angles and loads until the optical fiber is fractured. Through the monitoring data, it can be concluded that the variation law of optical fiber strain can basically reflect the propagation trend of the cracks in hydraulic concrete structures.

• Nuclear Engineering and Technology
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• 제33권5호
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• pp.483-497
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• 2001

In this work, a neuro-fuzzy inference system combined with the wavelet denoising, PCA (principal component analysis) and SPRT (sequential probability ratio test) methods is developed to detect the relevant sensor failure using other sensor signals. The wavelet denoising technique is applied to remove noise components in input signals into the neuro-fuzzy system The PCA is used to reduce the dimension of an input space without losing a significant amount of information. The PCA makes easy the selection of the input signals into the neuro-fuzzy system. Also, a lower dimensional input space usually reduces the time necessary to train a neuro-fuzzy system. The parameters of the neuro-fuzzy inference system which estimates the relevant sensor signal are optimized by a genetic algorithm and a least-squares algorithm. The residuals between the estimated signals and the measured signals are used to detect whether the sensors are failed or not. The SPRT is used in this failure detection algorithm. The proposed sensor-monitoring algorithm was verified through applications to the pressurizer water level and the hot-leg flowrate sensors in pressurized water reactors.

• 센서학회지
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• 제24권2호
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• pp.96-100
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• 2015

In the present study, we developed a real-time radiation-monitoring sensor for an underwater radiation-monitoring system and evaluated its effectiveness using reference radiation sources. The monitoring sensor was designed and miniaturized using a silicon photomultiplier (SiPM) and a cerium-doped-gadolinium-aluminum-gallium-garnet (Ce:GAGG) scintillator, and an underwater wireless monitoring system was implemented by employing a remote Bluetooth communication module. An acrylic water tank and reference radiation sources ($^{137}Cs$, $^{90}Sr$) were used to evaluate the effectiveness of the monitoring sensor. The underwater monitoring sensor's detection response and efficiency for gamma rays and beta particles as well as the linearity of the response according to the gammaray intensity were verified through an evaluation. This evaluation is expected to contribute to the development of base technology for an underwater radiation-monitoring system.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2004년도 학술대회지
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• pp.130-136
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• 2004

Presence of water in the lubricating oils could be one of the first indicators of potentially expensive and possibly catastrophic failure of the machine as it may cause displace the oil films to prevent the lubrication function of the oil or chemically react with many oil additives resulting in the oil degradation. In order to detect water content quantitatively in lubricating oils many methods and sensors has been developed. Among these, capacitive sensors including sensitive layer, whose dielectric factor changes according to the water content absorbed in the layer, are proposed mainly in the market. But these sensors are not sensitive to a high water content. Besides, the absorbing layer soils in time. In this work, an evaporation of water moisture from oil into air volume above lubricant surface and condensation of water vapor at a cooling surface was used to measure water content quantitatively in an lubricating oil. Laboratory test results of a prototype sensor were presented. Test results showed that the proposed method could be avaliable to measure a low levels of oil moisture.

• Journal of Magnetics
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• 제14권2호
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• pp.80-85
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• 2009

The mineral dissolution sensor system using GMR-SV and glass/Mg(200 nm) was prepared and characterized. The magnetic field sensitivity of GMR-SV to microscopic magnetic variation was about 0.8%/Oe. The change that occurs when Mg-film dissolves in water, the solubility of water, which is one of the basic properties of mineral water, was sensed by measuring the subtle variation of an electric current. In the case of edible water with Mg mineral added, bubbles were generated on the surface of the Mg film in the first 45 minutes, and the number of drops that were dissolved more rapidly than with the tap and DI waters later reduced to zero. For the edible water samples that each had different mineral Mg concentrations, the Mg solubility speed significantly differed. After injecting Mg film into the edible water, the magnetoresistance of the output GMR-SV signal decreased from a maximum of $45.4\;{\Omega}$ to a minimum of $43.6\;{\Omega}$. The measurement time was within 1 min, giving the rate of change ${\Delta}R/{\Delta}t=0.18\;{\Omega}/s$. This measurement system can be applied to develop a mineral Mg solubility GMR-SV sensor that can be used to sense the change from edible water to reduced alkali.

• International Journal of Precision Engineering and Manufacturing
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• 제5권2호
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• pp.46-52
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• 2004

Numerous connectors are used in automobiles for transmission of electrical signals across various electro-mechanical components. The connectors must operate with high reliability in order to minimize failures due to signal degradation. In this work, the effects of contamination at the contact interface of connectors used fur automobile crankshaft position sensor on the impedance change were investigated. An experimental set-up was built to simulate the electrical signal transmitted from the sensor to the engine control unit through a connector. Output from the connector was investigated using connectors contaminated with engine block residues and water droplets. It was found that slight contamination of the connectors could lead to significant signal degradation which can lead to engine failure. Also, the effect of water in the connector altered the signal severely. However, the signal gradually regained the original state as the water evaporated from the interface.