• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.137-137
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• 2020

국지성 집중호우의 증가로 인하여 각종 수재해 역시 증가하고 있으며 수재해 피해를 막기 위해서는 강우량 정보는 매우 중요한 요소이다. 이러한 강우량의 관측은 물론 미계측 지역의 강우량 추정을 위한 면적강우량 산정은 매우 중요하며 이에 관한 연구가 활발하게 수행되고 있다. 차량용 레인센서는 강우측정이 어려운 미계측 지역의 강수량 측정이 가능하고, 실시간으로 강우정보를 생성이 가능한 강우관측 방법이다. 차량용 강우센서는 일반적인 강우관측기와 달리 물 입자가 커질수록 빛의 산란이 크게 일어나는 현상을 이용한다. 산란이 크게 일어나면 강우 센서에 입력되는 값이 줄고 이는 강수가 높다는 것을 의미하고 이러한 관계를 이용하여 강원대학교 S-R 관계식을 통해 강우량을 관측할 수 있다. 본 연구에서는 강원도 삼척시를 대상지역으로 선정하였고 삼척 레이다 정보와 인근 지상관측소 6개 정보를 이용하여 강우보정을 수행하고 차량용 레인센서 강우관측 위치는 삼척시가지 내에서 강우를 관측하였다. 보정된 강우장과 레인센서 강우자료와 삼척관측소를 제외한 5개 지상관측소 강우정보를 합성하여 면적강우량을 산정하였고 검증을 위하여 삼척관측소 강우량과 면적강우의 해당격자의 강우량 값을 비교하여 검증하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.2
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• pp.227-235
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• 2018

In this study, we developed a relational formula for observing high - resolution rainfall using vehicle rain sensor. The vehicle rain sensor consists of eight channels. Each channel generates a sensor signal by detecting the amount of rainfall on the windshield of the vehicle when rainfall occurs. The higher the rainfall, the lower the sensor signal is. Using these characteristics of the sensor signal generated by the rain sensor, we developed a relational expression. In order to generate specific rainfall, an artificial rainfall generator was constructed and the change of the sensor signal according to the variation of the rainfall amount in the artificial rainfall generator was analyzed. Among them, the optimal sensor channel which reflects various rainfall amounts through the sensitivity analysis was selected. The sensor signal was generated in 5 minutes using the selected channel and the representative values of the generated 5 - minute sensor signals were set as the average, 25th, 50th, and 75th quartiles. The calculated rainfall values were applied to the actual rainfall data using the constructed relational equation and the calculated rainfall amount was compared with the rainfall values observed at the rainfall station. Although the reliability of the relational expression was somewhat lower than that of the data of the verification result data, it was judged that the experimental data of the residual range was insufficient. The rainfall value was calculated by applying the developed relation to the actual rainfall, and compared with the rainfall value generated by the ground rainfall observation instrument observed at the same time to verify the reliability. As a result, the rain sensor showed a fine rainfall of less than 0.5 mm And the average observation error was 0.36mm.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.5
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• pp.223-228
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• 2018

In this paper the water sensor using a coaxial cavity resonator is designed and manufactured. The water sensor which can sense water drop linearly has been constructed with voltage controlled oscillator(VCO), coaxial cavity resonator, RF switch, RF detector, A/D converter, DAC and micro controller. The operating frequency range of the designed water sensor is from 2.5GHz to 3.2GHz and the input voltage and current source are 24[V/DC] and 1[A]. The designed sensor circuit includes VCO, RF switch, RF detector which varies the frequency characteristics of the devices in the high frequency of 3GHz. And so we should correct the error of the frequency characteristics of those devices in the sensor circuit. To do this, we make the reference path which switches the signals to the RF detector directly without sending it to the resonator. According to the result of simulation and measurement, we can see that there is 0-50MHz difference between simulated resonator frequency and manufactured resonator frequency.

• Journal of the Microelectronics and Packaging Society
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• v.9 no.3
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• pp.37-41
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• 2002

In this research, we investigate the properties of membrane and thin film sensor which is using magnetic resonance properties. we expect to $Si_xN_y$ and SiC materials as membrane materials, we measured thin film stress and properties to find the best membrane fabrication condition. Of the two membrane, $Si_xN_y$ thin film is the better than SiC thin film. because of an adequate tensile stress and lower thermal expansion coefficient as sensor structure layer. After performing deposition and patterning thin film sensor material on $Si_xN_y$, we analyzed the magnetic hysteresis and magnetic resonance frequency of sensor. If the magnetic field which is applied in sensor material is removed, magnetization made by magnetic field is transited to elastic mode. moreover. energy radiation is induced during the transition and voltage generates in sensor by energy radiation. At this moment, If voltage generation period is longer, mechanical vibration is induced and signal is generated by mechanical vibration. we also see that as the increase of thin film sensor' length and width, magnetic resonance frequency is decreased.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2022.10a
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• pp.417-418
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• 2022

최근 기후변화와 집중호우, 도시배수체계의 한계로 인해 도시침수가 빈번하게 일어나고 있으며 이에 따른 인적·물적 피해가 지속적으로 발생하고 있다. 기후변화 보고서에 따르면 우리나라 강우량은 21세기 후반까지 증가할 것으로 예측되고 있어 도시 침수 피해를 사전에 예측하고 피해 규모를 감소시키기 위한 위기 대응 시스템의 개발이 필요하다. 본 논문에서는 효율적이고 정확한 도시침수 상황관리를 가능하게 하기 위해 센서 계측 기술, IoT, 빅데이터 등의 최신 기술을 적용한 도시침수 모니터링 시스템을 설계하였다. 도시침수 모니터링 시스템은 스마트 레인센서, 스마트 지표 침수계측센서, 스마트 지표하 침수계측센서 등 다양한 종류의 센서와 연동되어 있으며 시스템에서 계측 데이터를 감시, 분석, 통계할 수 있어 효율적인 재난관리 대응이 가능하다. 또한, 도시침수 모니터링 시스템은 재난상황 발생 시 사전에 침수예상지역을 분석하고 대피계획 및 시점을 제공함으로써 인명피해를 줄이고 급작스런 홍수에 대비할 수 있다.

• Membrane Journal
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• v.31 no.2
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• pp.87-100
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• 2021

With a striking increase in the level of contamination and subsequent degradations in the environment, detection and monitoring of contaminants in various sites has become a crucial mission in current society. In this review, we have summarized the current research areas in membrane-based colorimetric sensors for trace detection of various molecules. The researches covered in this summary utilize membranes composed of cellulose fibers as sensing platforms and metal nanoparticles or fluorophores as optical reagents. Displaying decent or excellent sensitivity, most of the developed sensors achieve a significant selectivity in the presence of interfering ions. The physical and chemical properties of cellulose membrane platforms can be customized by changing the synthesis method or type of optical reagent used, allowing a wide range of applications possible. Membrane-based sensors are also portable and have great mechanical properties, which enable on-site detection of contaminants. With such superior qualities, membrane-based sensors examined in the researches were used for versatile purposes including quantification of heavy metals in drinking water, trace detection of toxic antibiotics and heavy metals in environmental water samples. Some of the sensors exhibited additional features like antimicrobial ability and recyclability. Lastly, while most of the sensors aimed for a detection enabled by naked eyes through rapid colour change, many of them investigated further detection methods like fluorescence, UV-vis spectroscopy, and RGB colour intensity.

• Journal of Sensor Science and Technology
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• v.9 no.1
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• pp.22-27
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• 2000

Amorphous FeCoSiB films with high saturation magnetostriction and excellent soft magnetic properties have been studied to evaluate their strain sensitivity. Films were subjected to a strain by bending of their substrates, which caused a change in the magnetic anisotropy of films via magnetoelastic coupling. Films were exhibited a figure of merit $F=({\Delta}{\mu}/{\mu})/{\varepsilon}$ (change in film permeability $\mu$ per unit strain $\varepsilon$) of $1.2{\times}10^5$, which is comparable with that of amorphous ribbons. To make a study of application of magnetostrictive films as strain sensor elements, we have prepared a micro-patterned film by means of the photolithography and ion milling processes. Impedance change in the patterned films, when strain was applied, was measured over the frequency range from 1 MHz to 1 GHz. Reflecting a large value of figure of merit F, a variation of 46% impedance of films was shown at 100 MHz frequency when a strain of $300{\times}10^{-6}$ was applied.

• Korean Journal of Optics and Photonics
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• v.8 no.4
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• pp.333-339
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• 1997

We fabricated a sensor head which consists of spliced different-diameter fiber gratings for discrimination between strain and temperature. Because the fibers were drawn from the same preform, their temperature characteristics were the same but not for strain sensitivities which are inversely proportional to fibers cross-sectional areas. In measurement range of 0-1500$\mu$strain and 20-10$0^{\circ}C$, we could obtain, by using the matrix calculation, the unknown physical quantities within 10% of calculation error compared with the micrometer and thermocouple values. To improve the strain measurement accuracy, we suggest a new, novel method which deploys an unbalanced fiber Mach-Zehnder interferometer. This new signal processing technique converts the strain information to interference signal amplitude variation, temperature-independently. we obtained measurement accuracy nearly 80 times better than that obtainable with the conventional optical spectrum analyzer usage.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.2
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• pp.147-151
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• 2001

An optical fiber sensor is capable of nondestructive measurement of a structure and it has an advantage of the immunity to electromagnetic interference because light is not affected by electromagnetic wave. In addition, if optical fibers are buried in an object like a concrete, this sensor tan analyze defects and physical status of the object without disassembling it. Especially, the fiber Bragg grating sensor is a promising optical fiber sensor capable of nondestructive test of such an object. A fiber Bragg grating has the characteristics of reflecting or blotting light of a specific wavelength. If we apply physical quantity like strain to the fiber Bragg grating, the center wavelength of the reflected light is shifted and then we can find the physical quantity applied to the fiber Bragg grating by measuring the center wavelength shift of the reflected light. The fiber Bragg grating sensor capable ot static and dynamic strain measurement is being used in health-monitoring of buildings, structures, etc. Recently increasing is interest in dynamic strain measurement inevitable to the civil structures such as roads and bridges. In this study we implemented the optical fiber sensor system which can measure dynamic strain at multiple points using Fabry-Perot wavelength demodulation. And we measured the static and dynamic strain using this sensor system with a test structure(cantilever). Measurement results were similar to those obtained with the conventional electrical measurement methods.

• 전자공학회논문지 IE
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• v.44 no.1
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• pp.6-9
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• 2007

Twenty four types of thermopile for micro spectrometer infrared sensors were fabricated on low-stress Si3N4 membranes with $l.2{\mu}m-thickness$ using MEMS technology. Thermopile were designed and fabricated for optimum conditions by five parameters of thermocouple numbers $(16\sim48)$, thermocouple line widths $(10{\mu}m-25{\mu}m)$, thermocouple lengths $(100{\mu}m-500{\mu}m)$, membrane areas $(12mm2\sim2.52mm2)$ and junction areas $(150{\mu}m2\sim750{\mu}m2)$, respectively. It was thought that measurement results could be used for thermopile infrared sensors optimum structure for micro spectrometers.