• 한국전자통신학회논문지
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• 제5권5호
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• pp.504-508
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• 2010

현 농촌사회는 점차 고령화 사회가 되어감에 따라 노동력 감소 문제점이 발생하고 있다. 본 연구을 통하여 생육 단계별 수위를 자동 컨트롤하여 관리할 수 있는 농작물의 수위 조절 시스템 연구 개발하였다. 수위측정에는 초음파 센서를, 급 배수로의 수문 제어에는 서보모터를 사용하고 이들의 신호를 처리하는 제어부로는 ATmega128을 사용하였다. 본 시스템을 통하여 노동력 감소의 문제점을 해결하고 농촌사회의 자동화 발전 및 고령화 사회에 큰 기여를 기대 할 수 있을 것이다.

• 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.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권3호
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• pp.380-386
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• 2016

This paper presents a compact and low-power on-chip touch sensor and readout circuit using shunt proximity touch sensor and its design scheme. In the proposed touch sensor readout circuit, the touch panel condition depending on the proximity of the finger is directly converted into the corresponding voltage level without additional signal conditioning procedures. Furthermore, the additional circuitry including the comparator and the flip-flop does not consume any static current, which leads to a low-power design scheme. A new prototype touch sensor readout integrated circuit was fabricated using complementally metal oxide silicon (CMOS) $0.18{\mu}m$ technology with core area of $0.032mm^2$ and total current of $125{\mu}A$. Our measurement result shows that an actual 10.4 inches capacitive type touch screen panel (TSP) can detect the finger size from 0 to 1.52 mm, sharply.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 영호남학술대회 논문집
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• pp.175-178
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• 2000

In this study, the ultrasonic transducer was fabricated with piezoceramic-polymer 1-3 type composites. Pulse-echo response of that transducer in water was investigated with variable water-level. Output of LED was under the control of the signal, which was analyzerd by the self-made Electric Unit. This paper represents automatically water-detecting system with variable water level. There was in good agreement water level between the virtual level and output signal by using the self-made water-detecting system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.86.5-86
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• 2001

This work describes a design and implementation of the level & flow rate control system by using a single-chip microcontroller. The proposed model system is designed based on the use of the single-chip microcontroller 8031 with the EPROM emulator for programming the computer software. The microcontroller reaches the input level and flow signals from the level sensor and the turbine flowmeter, respectively, via the signal conditioning circuits and A/D converters in order to calculate the control signal. Moreover, the status of the process variable can easily be set up and controlled by program monitoring through the emulator, and can be graphically displayed on the computer screen. Experiment results were carried out which can be ...

• 한국가스학회지
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• 제14권4호
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• pp.56-62
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• 2010

본 논문은 LPG 엔진의 전자제어센서에 대한 고장사례를 분석하고 고찰한 연구이다. LP가스의 연료 분사량을 컨트롤하는 크랭크 각도센서의 기능이상은 불규칙하고 불균일한 파형형태로 나타나고 있다. 크랭크 각도센서의 노이즈에 관련된 파형은 톱니형의 불규칙한 피크형상으로 나타났고, 2.46V 정도의 노이즈 레벨이 간헐적으로 발생하고 있다. 1번 TDC센서의 내부불량으로 인해 발생한 고장사례는 엔진의 출력을 떨어뜨리고 시동을 간헐적으로 꺼지게 하는 문제점을 초래한다. 산소센서의 성능이상은 센서의 배선에서 연결이 단절되었기 때문에 발생한 것으로 차량의 울컥거리는 현상과 엔진의 부조화 현상이 나타나고 있다. 에어 크리너를 이종품으로 사용한 경우는 신기가 정상적으로 공급되지 못했기 때문에 차량의 가속불량과 엔진의 부조화 현상이 발생하는 원인으로 작용하고 있었다.

• Nuclear Engineering and Technology
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• 제33권5호
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• pp.457-467
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• 2001

It is well known that the performance of a fuzzy neural network strongly depends on the input features selected for its training. In its applications to sensor signal estimation, there are a large number of input variables related with an output As the number of input variables increases, the training time of fuzzy neural networks required increases exponentially. Thus, it is essential to reduce the number of inputs to a fuzzy neural network and to select the optimum number of mutually independent inputs that are able to clearly define the input-output mapping. In this work, principal component analysis (PCA), genetic algorithms (CA) and probability theory are combined to select new important input features. A proposed feature selection method is applied to the signal estimation of the steam generator water level, the hot-leg flowrate, the pressurizer water level and the pressurizer pressure sensors in pressurized water reactors and compared with other input feature selection methods.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.27-30
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• 2003

In this paper a new approach of digitalized ‘Takbon’ is introduced. By image signal processing, the letters which were written on stones can be deciphered. Epigraphic letter is detected by digital image device, digital camera. The two dimensional digital image is preprocessed because of sensor noise and detective turbulence. Color image is transformed into grey level. The letter image is analyzed in time/frequency domain. By the resultant analysis data decisive functions are calculated. Signal Processing techniques, such as scaling, clipping, digital negative, high/low filter, morphology and so on, provide algorithms that can extract letter from stones.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.376-380
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• 2009

Surface acoustic wave (SAW) device is widely used as a bandpass filter, a chemical or physical sensor, and an actuator. In this paper, we propose the capacitive gap measurement system with high precision through the signal processing using SAW device. The research process is mainly composed of theoretical part and experimental part. In theoretical part, equivalent circuit model was used to simulate the SAW response by the change of capacitance. In experimental part, commercialized capacitor was used to see the SAW response by the change of load capacitance. After that, gap adjustment system was made physically and the SAW response by the change of gap which caused the capacitance change was measured. And resolution and stroke was decided comparing the signal change and basic measurement noise level.

• Smart Structures and Systems
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• 제22권2호
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• pp.239-247
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• 2018

A magnetic flux leakage (MFL) method was applied to detect and quantify defects in a steel bar. A multi-channel MFL sensor head was fabricated using Hall sensors and magnetization yokes with permanent magnets. The MFL sensor head scanned a damaged specimen with five levels of defects to measure the magnetic flux density. A series of signal processing procedures, including an enveloping process based on the Hilbert transform, was performed to clarify the flux leakage signal. The objective damage detection of the enveloped signals was then analyzed by comparing them to a threshold value. To quantitatively analyze the MFL signal according to the damage level, five kinds of damage indices based on the relationship between the enveloped MFL signal and the threshold value were applied. Using the proposed damage indices and the general damage index for the MFL method, the detected MFL signals were quantified and analyzed relative to the magnitude of the damage increase.