• 센서학회지
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• 제16권2호
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• pp.97-103
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• 2007

Crystallized carbon nitride film that has many stable physical and/or chemical properties has been expected potentially by a new electrical material. However, one of the most significant problems degrading the quality of carbon nitride films is an existence of N-H and C-H bonds from the deposition environment. The possibility of these reactions with hydroxyl group in carbon nitride films, caused by a hydrogen attack, was suggested and proved in our previous reports that this undesired effect could be applied for fabricating micro-humidity sensors. In this study, MIS capacitor and MIM capacitor with $5{\mu}m{\times}5{\mu}m$ meshes were fabricated. As an insulator, carbon nitride film was deposited on a $Si_{3}N_{4}/SiO_{2}/Si$ substrate using reactive magnetron sputtering system, and its dielectric constant, C-V characteristics and humidity sensing properties were investigated. The fabricated humidity sensors showed a linearity in the humidity range of 0 %RH to 80 %RH. These results reveal that MIS and MIM $CN_{X}$ capacitive humidity sensors can be used for Si based micro-humidity sensors.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1796-1797
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• 2011

본 연구에서는 기존 오실로메트리(oscillomatry) 혈압측정에서 가압 커프의 영향을 최소화 하기위하여, 캐패시턴스 센서를 추가하여 혈압측정 동안의 혈압 및 혈류의 변화량을 측정하여 얻은 신호로 수축기 혈압 및 이완기 혈압을 추정하였다. 필터를 적용한 캐패시턴스 센서의 값을 피크의 크기에 따른 알고리즘을 적용하였으며 얻어진 혈압값과 기존의 혈압계의 값을 비교분석 하였다. 피험자의 연령은 $25{\pm}4$세의 15명을 기준으로 실험하였으며 알콜 및 운동 등 혈압에 영향을 미치는 요소들에 대해 제한 시켰으며 측정 전 15분의 안정을 취했다. 결과적으로 피험자 15명에 대해 수축기 혈압에서의 오차범위는 ${\pm}4$ mmHg이하로 나타났으며 평균 및 표준편차는 각각 2.13 mmHg 과 1.36 mmHg이었다. 이완기 혈압에서는 오차범위가 11명에 대해 수축기혈압과 같았으며 4명은 ${\pm}7mmHg$이상 이였고 평균과 표준편차는 4.20 mmHg와 2.24 mmHg 로 수축기 혈압에서 오차 및 분산 모두 이완기혈압 추정보다 비교적 정확한 값을 검출했다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2017년도 춘계학술발표대회
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• pp.1131-1134
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• 2017

본 연구는 차동 용량형 섬유 압력 센서를 개발하고, 이를 깔창에 부착하여 보행 측정에 응용하는 것을 목적으로 한다. 차동 용량형 섬유 압력 센서는 3장의 전도성 섬유 사이에 2장의 절연체를 위치시키는 형태로, $5cm{\times}5cm{\times}0.23cm$ (가로 ${\times}$ 세로 ${\times}$ 두께) 크기로 제작하였다. 커패시턴스를 측정하기 위해 커패시턴스-디지털 변환칩(AD7152), ATMega328로 구성된 시스템을 제작하였고 PC로 데이터를 전송하여 모니터링을 수행하였다. 센서의 힘-커패시턴스 변화 특성 평가를 위해 센서에 가하는 중량을 65 kg 까지 5 kg 씩 증가시켜 가며 커패시턴스 변화를 측정하였다. 실험 결과, 무게에 따라 커패시턴스가 증가하는 것을 확인하였다. 보행 측정 가능성을 평가하기 위해 센서를 깔창에 부착한 후 보행 신호를 측정하였으며, 그 결과 보행에 따라 센서의 커패시턴스 값이 변화하는 것을 확인하였다. 이로부터 제작한 차동용량형 섬유 센서는 보행 측정에 활용할 수 있는 가능성을 확인하였다.

• 센서학회지
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• 제23권5호
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• pp.326-331
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• 2014

In this study, a MEMS microphone that uses $Si_3N_4$ as the vibration membrane was produced for application as an auditory device using a sound visualization technique (sound visualization) for the hearing impaired. Two sheets of 6-inch silicon wafer were each fabricated into a vibration membrane and back plate, after which, wafer bonding was performed. A certain amount of charge was created between the bonded vibration membrane and the back plate electrodes, and a MEMS microphone that functioned through the capacitive method that uses change in such charge was fabricated. In order to evaluate the characteristics of the prepared MEMS microphone, the frequency flatness, frequency response, properties of phase between samples, and directivity according to the direction of sound source were analyzed. The MEMS microphone showed excellent flatness per frequency in the audio frequency (100 Hz-10 kHz) and a high response of at least -42 dB (sound pressure level). Further, a stable differential phase between the samples of within -3 dB was observed between 100 Hz-6 kHz. In particular, excellent omnidirectional properties were demonstrated in the frequency range of 125 Hz-4 kHz.

• International Journal of Internet, Broadcasting and Communication
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• 제7권2호
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• pp.73-78
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• 2015

Touch panel is mainly applied to pressure type touch panel but it occur a low recognition rate and error during long-term use. So, it is partly applied to capacitive touch panel to compensate for these problems but it also can occur a same problems via pollutions. Touch technology has developed a various method but it is not used because of high costs and difficult installation process. So, in this paper, we proposed an input method of touchless panel using IrDA matrix. This method is conducted using an IrDA Matrix composed of depth sensor. It is possible to offer a various contents for multi user. The proposed technology need a development of a high sensitivity sensing method and high-speed processing method of position information for Seamless operation control. And, it is required high-precision drive technology. Also, we proposed a Seamless user recognition for interactive contents service through a touchless panel using IrDA matrix.

• ETRI Journal
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• 제38권2호
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• pp.235-243
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• 2016

A low-noise readout integrated circuit (ROIC) for a microelectromechanical systems (MEMS) microphone is presented in this paper. A positive feedback signal amplification technique is applied at the front-end of the ROIC to minimize the effect of the output buffer noise. A feedback scheme in the source follower prevents degradation of the noise performance caused by both the noise of the input reference current and the noise of the power supply. A voltage booster adopts noise filters to cut out the noise of the sensor bias voltage. The prototype ROIC achieves an input referred noise (A-weighted) of -114.2 dBV over an audio bandwidth of 20 Hz to 20 kHz with a $136{\mu}A$ current consumption. The chip is occupied with an active area of $0.35mm^2$ and a chip area of $0.54mm^2$.

• 한국정밀공학회지
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• 제34권1호
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• pp.53-58
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• 2017

A fine stage is developed for the 3-DOF error compensation of a linear axis in order to improve the positioning accuracy. This stage is designed as a planar parallel mechanism, and the joints are based on a flexure hinge to achieve ultra-precise positioning. Also, the effect of Abbe's offsets between the measuring and driving coordinate systems is minimized to ensure an exact error compensation. The mode shapes of the designed stage are analyzed to verify the desired 3-DOF motions, and the workspace and displacement of a piezoelectric actuator (PZT) for compensation are analyzed using forward and inverse kinematics. The 3-DOF error of a linear axis is measured and compensated by using the developed fine stage. A marked improvement is observed compared to the results obtained without error compensation. The peak-to-valley (PV) values of the positional and rotational errors are reduced by 92.6% and 91.3%, respectively.

• 한국생산제조학회지
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• 제19권6호
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• pp.797-803
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• 2010

A method has been developed to tune the static stiffness at a rotation joint considering the whole machine tool system by interactive use of finite element method and experiment. This paper describes the procedure of this method and shows the results. The method uses the static experiment on measurement model which is set-up so that the effects of uncertain factors can be excluded. For FEM simulation, the rotation joint model is simplified using only spindle, bearing and spring. At the rotation joint, the damping coefficient is ignored, The spindle and bearing is connected by only spring. By static experiment, 500 N is forced to the front and behind portion of spindle and the deformation is measured by capacitive sensor. The deformation by FEM simulation is extracted with changing the static stiffness from the initial static stiffness considering only rotation joint. The tuning static stiffness is obtained by exploring the static stiffness directly trusting the deformation from the static experiment. Finally, the general tuning method of the static stiffness of machine tool joint is proposed using the force stream and the modal analysis of machine tool.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권6호
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• pp.733-740
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• 2014

A resistive micro Pirani gauge using amorphous silicon (a-Si) thin membrane is proposed. The proposed Pirani gauge can be easily integrated with the other process-compatible membrane-type sensors, and can be applicable for in-situ vacuum monitoring inside the vacuum package without an additional process. The vacuum level is measured by the resistance changes of the membrane using the low noise correlated double sampling (CDS) capacitive trans-impedance amplifier (CTIA). The measured vacuum range of the Pirani gauge is 0.1 to 10 Torr. The sensitivity and non-linearity are measured to be 78 mV / Torr and 0.5% in the pressure range of 0.1 to 10 Torr. The output noise level is measured to be $268{\mu}V_{rms}$ in 0.5 Hz to 50 Hz, which is 41.2% smaller than conventional CTIA.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권5호
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• pp.204-212
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• 2002

In order to improve the reliability of high voltage rotating machines, it is necessary to understand the breakdown mechanism of stator windings. Especially partial discharge(PD) inception and growth are important in stator winding insulation. Recently, many research on the diagnosis of stator winding insulation for large rotating machines have been developed since the 1970s. Capacitive couplers have been the most widely used sensor for on-line partial discharge detection in rotating machines. This paper deals with the electrical on-line monitor characteristics of ceramic coupler(CC) which has been developed to continuously measure the PD activity in operating high voltage motor stator windings on site. We investigated the electrical characteristics(PD quantity, breakdown voltage and frequency response) to develop CC. This paper presents frequency characteristics and laboratory test result to compare conventional 80([F] epoxy-mica coupler(EMC) and 105[pF] CC for PD measurement with 6.6㎸ model stator windings.