• Journal of the Semiconductor & Display Technology
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• v.18 no.4
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• pp.87-91
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• 2019

The diagnosis of the failure for the existing electrical facilities was based on regular preventive maintenance, but this preventive maintenance was limited in preventing a lot of cost loss and sudden system failure. To overcome these shortcomings, fault prediction and diagnostic techniques are critical to increasing system reliability by monitoring electrical installations in real time and detecting abnormal conditions in the facility early. As the performance and quality deterioration problem occurs frequently due to the increase in the number of users of the motor pump, the purpose is to build an intelligent control system that can control the motor pump to maximize the performance and to improve the quality and reliability. To this end, a vibration sensor, temperature sensor, pressure sensor, and low water level sensor are used to detect vibrations, temperatures, pressures, and low water levels that can occur in the motor pump, and to build a system that can identify and diagnose information to users in real time.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.401-408
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• 2022

As research on a controlled environment system based on crop growth environment sensing for sustainable production of horticultural crops and its industrial use has been important, research on how to properly utilize soil moisture sensors for outdoor cultivation is being actively conducted. This experiment was conducted to suggest the proper method of utilizing the TEROS 12, an FDR (frequency domain reflectometry) sensor, which is frequently used in industry and research fields, for each orchard soil in three regions in Korea. We collected soils from each orchard where fruit trees were grown, investigated the soil characteristics and soil water retention curve, and compared TEROS 12 sensor calibration equations to correlate the sensor output to the corresponding soil volumetric water content through linear and cubic regressions for each soil sample. The estimated value from the calibration equation provided by the manufacturer was also compared. The soil collected from all three orchards showed different soil characteristics and volumetric water content values by each soil water retention level across the soil samples. In addition, the cubic calibration equation for TEROS 12 sensor showed the highest coefficient of determination higher than 0.95, and the lowest RMSE for all soil samples. When estimating volumetric water contents from TEROS 12 sensor output using the calibration equation provided by the manufacturer, their calculated volumetric water contents were lower than the actual volumetric water contents, with the difference up to 0.09-0.17 m³·m^-3 depending on the soil samples, indicating an appropriate calibration for each soil should be preceded before FDR sensor utilization. Also, there was a difference in the range of soil volumetric water content corresponding to the soil water retention levels across the soil samples, suggesting that the soil water retention information should be required to properly interpret the volumetric water content value of the soil. Moreover, soil with a high content of sand had a relatively narrow range of volumetric water contents for irrigation, thus reducing the accuracy of an FDR sensor measurement. In conclusion, analyzing soil water retention characteristics of the target soil and the soil-specific calibration would be necessary to properly quantify the soil water status and determine their adequate irrigation point using an FDR sensor.

• Journal of Sensor Science and Technology
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• v.6 no.6
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• pp.508-513
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• 1997

We exploited a new molecular system - acetylcholine (neurotransmitter) detection system as a building block for the perfect molecular information system (sensing membrane of the chemical sensor) - using water soluble calix[n]arene-p-sulfonates which are useful even in aqueous (water/methanol) neutral solution. This achievement is due to several outstanding properties of these calix[n]arene derivatives such as low $pK_{a}$ values, cation-interactions, and high water-solubility, etc.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.160-164
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• 2000

This paper describes oil water separator using difference of electrical resistor. Oil is a non-conductive element and water is a relatively high conductive element. It is possible to detect water included in oil. Electric sensor is formed 8mm iron stick. Valve is operated With controller inputting signal of electric sensor. A experiment was done for necessary voltage in making program of controller. Oil water separator which was tested in field conditions was saved 7% of whole oil and was drained over 150% water than manual valve.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.849-851
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• 2010

This paper applicate to the large flowers management house, personal office or home, which breed flowers for the profit or hobby. We suggest flower water supply assistant, which supply water anytime to prevent die from water shortage. Our system applicate to the flowerpot less than two at first. We measure humidity by use humidity sensor and control water supply valve automatically. The water supply valve will be opened when the humidity drop to the less than critical values.

• Journal of Hydrogen and New Energy
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• v.33 no.4
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• pp.353-362
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• 2022

In this study, water diffusion in proton exchange membrane fuel cell at open circuit voltage (OCV) was analyzed through experiment. First, the reliability of the micro-sensor (SHT31) was verified. It was concluded the micro-sensor has an excellent reliability at 60℃ and 70℃. After the sensor reliability test, the temperature and relative humidity measurement in bipolar-plate was conducted at OCV. To analyze water distribution and water flux, the temperature and relative humidity was converted into dew point. To the end, it was found water concentration affects water diffusion.

• International journal of advanced smart convergence
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• v.5 no.2
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• pp.73-79
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• 2016

Remote sensing and measurement are of paramount importance of providing information on the state of water quality in water bodies. The formation and growth of cyanobacteria is of serious concern to in land aquatic life forms and human life. The main cause of water quality deterioration stems from anthropogenic induced eutrophication. The goal of this research to quantify and determine the spatial distribution of cyanobacteria concentration in the water using remote sensing technique. The standard approach to measure water quality based on the direct measurement of the fluorescence of the chlorophyll a in the living algal cells and the same approach used to detect the phycobilin pigments found in blue-green algae (a.k.a. cyanobacteria), phycocyanin and phycoerythrin. This paper propose the emerging sensor design to measure the water quality based on the optical analysis by fluorescence of the phycocyanin pigment. In this research, we developed an method to sense and quantify to derive phycocyanin intensity index for estimating cyanobacteria concentrations. The development of the index was based on the reflectance difference between visible light band 620nm and 665nm. As a result of research this paper presents, an optical biological sensor design information to measure the Phycocyanin parameters in water content.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.5
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• pp.43-51
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• 2011

Irrigation facilities are spread over demand area in a low density and exposed in the field requiring efficient operation and maintenance. Thus, it could be more efficient to manage an irrigation system when it is with wireless sensor network (WSN) using RFID (Radio Frequency Identification) application. A WSN, a kind of ubiquitous sensor network composed of wireless network, RFID and database management system was developed for agricultural water management in terms of operational status and maintenance requirements. Identification code for RFID tag was designed and an application for RFID reader was developed for field data collection, and a database management system was constructed for managing irrigation facility attributes. The system was installed in I-dong irrigation districts in Gyounggi-province, Korea and the operated results showed the applicability of the WSN for agricultural water management.

• Journal of Biosystems Engineering
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• v.34 no.6
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• pp.434-438
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• 2009

This study was conducted to design an cone penetrometer type impedance sensor that can measure soil water content in realtime. The best width between electrical probe was determined by 5 mm. For optimization about realtime application device, linear regression analysis was applied between soil water content and impedance signal. It was concluded that proper combination of excitation frequency, impedance parameter, and model would provide acceptible performance of a soil waler content sensoe. Best model was obatained at a 36.5 MHz with |Z| as a predictor variable, with a coefficient of determination of 0.96 (RMSE=1.35, RPD=4.98).

• Journal of Sensor Science and Technology
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• v.33 no.5
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• pp.378-383
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• 2024

This study developed a buoyancy-based level sensor composed of a buoyant object, a sensing unit, and a signal generation unit to meet the demand of low-cost, high-efficiency inundation-detection sensors. The volume of the submerged buoyant object remained nearly constant even in the presence of water-level fluctuations, allowing stable water-level data acquisition. The measurement resolution and measurement repeatability were confirmed to be within 0.4 mm and 0.3%, respectively. LoRa-based communication was used to implement the IoT-based inundation-detection sensor. The measurement deviation between the sensors is approximately 0.15%. The unresponsive level at which measurement was not possible was confirmed to be approximately 2 mm. Excluding this unresponsive range, the water level measurements exhibited very high linearity, allowing precise measurements. Furthermore, a test bed was established in an inundation-vulnerable area using buoyancy-based level sensors.