• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.834-837
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• 2005

In this paper, we describe the method of non-invasive blood pressure measurement using pulse wave transit time(PWTT). PWTT is a new parameter involved with a vascular that can indicate the change of BP. PWTT is measured by continuous monitoring of ECG and pulse wave. No additional sensors or modules are required. In many cases, the change of PWTT correlates with the change of BP. We measure pulse wave using the photo plethysmograph(PPG) sensor in an earlobe and we measure ECG using the ECG monitoring device our made in the chest. The measurement device for detecting pulse wave consists of infrared LED for transmitted light illumination, pin photodiode as light detector, amplifier and filter. We composed 0.5Hz high pass, 60Hz notch and 10Hz low pass filter. ECG measurement device consists of multiplexer, amplifier, filter, micro-controller and RF module. After amplification and filtering, ECG signal and pulse wave is fed through micro-controller. We performed the initial work towards the development of ambulatory BP monitoring system using PWTT. An earlobe is suitable place to measure PPG signal without the restraint in daily work. From the results, we can know that the dependence of PWTT on BP is almost linear and it is possible to monitoring an individual BP continuously after the individual calibration.

• Bulletin of the Korean Chemical Society
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• 제24권3호
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• pp.279-284
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• 2003

The One Pass Method (OPM) previously presented for the identification of single input single output systems is used to estimate the parameters of a Decentralized Control System (DCS). The OPM is a linear and therefore a simple estimation method. All of the calculations are performed in one pass, and no initial parameter guess, iteration, or powerful search methods are required. These features are of interest especially when the parameters of multi input-output model are estimated. The benefits of the OPM are revealed by comparing its results against those of two recently published methods based on pulse testing. The comparison is performed using two databases from the literature. These databases include single and multi input-output process transfer functions and relevant disturbances. The closed loop responses of these processes are roughly captured by the previous methods, whereas the OPM gives much more accurate results. If the parameters of a DCS are estimated, the OPM yields the same results in multi or single structure implementation. This is a novel feature, which indicates that the OPM is a convenient and practice method for the parameter estimation of multivariable DCSs.

• 한국산학기술학회논문지
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• 제10권7호
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• pp.1526-1531
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• 2009

RFID Reader IC에 응용하기 위한 저전압 특성의 5차 일립틱 CMOS Gm-C 필터를 설계하였다. 설계된 필터는 CMOS 자기바이어스 차동 트랜스컨덕터를 설계하여 구성하였으며 차동 트랜스컨덕터는 기존의 자기 바이어스 차동증폭기의 이득특성을 개선하기 위하여 병렬형으로 구성되었다. 설계된 필터는 RFID 리더용 저전압 필터 설계사양에 따라 1.8V의 저전압으로 동작이 가능하도록 설계되었다. 1.8V, 0.18${\mu}m$CMOS 공정 파라미터를 사용하여 HSPICE 시뮬레이션 결과, 설계된 5차 일립틱 저역 필터가 설계사양인 1.35MHz의 차단주파수를 만족함을 확인하였다.

• 대한기계학회논문집A
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• 제41권4호
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• pp.307-312
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• 2017

레이저 클래딩은 아크 용접 및 용사와 같은 기존 클래딩 기술보다 우수한 장점을 가진다. 레이저 클래딩으로 형성한 클래드 층의 희석률은 낮으며 모재와의 결합력이 우수하고 결함이 거의 존재하지 않는다. 이러한 특징을 가진 레이저 클래딩을 실제 선박용 배기밸브에 적용하기에 위해 지난 제1보의 논문에서 조사한 공정변수에 따른 1 패스 클래드 층의 특성을 통해 넓은 면적에 클래딩 시 1 패스 클래드 층의 중첩이 필수적이라는 것을 알 수 있었다. 따라서 본 논문에서는 중첩률에 따른 멀티패스 클래드 층의 형상 차이를 비교하고 일정 중첩률 조건에서 EDS 및 EPMA를 통해 합금 성분 분포를 파악하였다. 실험결과, 중첩률이 증가할수록 클래드 층의 길이가 감소하고 높이가 증가하였으며 동일한 조건의 1 패스 클래드 층보다 높이가 상승하였다. 성분 분석을 통해 모재 희석이 많이 발생한 첫 번째 클래드 층에서 Fe이 높게 측정되었으나 나머지 영역에서는 희석이 감소하여 Co가 증가하고 Fe이 감소하였으며 균일한 성분 분포가 관찰되었다.

• ETRI Journal
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• 제29권3호
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• pp.300-304
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• 2007

This paper proposes a new data-driven method for high-pass approaches, which suppresses slow-varying noise components. Conventional high-pass approaches are based on the idea of decorrelating the feature vector sequence, and are trying for adaptability to various conditions. The proposed method is based on temporal local decorrelation using the information-maximization theory for each utterance. This is performed on an utterance-by-utterance basis, which provides an adaptive channel normalization filter for each condition. The performance of the proposed method is evaluated by isolated-word recognition experiments with channel distortion. Experimental results show that the proposed method yields outstanding improvement for channel-distorted speech recognition.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.468-471
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• 2005

The Air Quality Sensor(AQS), located near the fresh air inlet, serves to reduce the amount of pollution entering the vehicle cabin through the HVAC(heating, ventilating, and air conditioning) system by sending a signal to close the fresh air inlet door/ventilation flap when the vehicle enters a high pollution area. One chip sensor module which include above two sensing elements, humidity sensor and bad odor sensor was developed for AQS (air quality sensor) in automobile. With this sensor module, PIC microcontroller was designed with back propagation neural network to reduce detecting error when the motor vehicles pass through the dense fog area. The signal from neural network was modified to control the inlet of automobile and display the result or alarm the situation. One chip microcontroller, Atmega128L (ATmega Ltd., USA) was used. For the control and display. And our developed system can intelligently detect the bad odor when the motor vehicles pass through the polluted air zone such as cattle farm.

• 한국물환경학회지
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• 제21권4호
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• pp.327-331
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• 2005

The study was conducted with two laboratory biological aerated filter (BAF) reactors: denitrification filter (DF) and nitrification BAF. The influent flow (Q) was fixed to 48 L/d and total empty bed contact time (EBCT) was 1 hr. The flow direction was upflow with NRCY of 1 to 2Q. The secondary effluent was fed to the reactors and the influent concentrations were adjusted with some stock solutions to simulate by-pass concentration during rainfall. The study results indicate that COD and SS removal efficiencies were excellent and not influenced by temperature. Nitrification efficiency was over 90% at the influent loading less than $1.12kg/media\;m^3/d$, but the efficiencies were decreased in low temperature. TN removal efficiencies were 10% to 60%.

• 한국해안해양공학회지
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• 제19권5호
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• pp.418-428
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• 2007

Boussinesq 방정식에 의한 파랑전파의 계산과정 중 파랑의 비선형 상호작용 및 쇄파발생에 의하여 수치잡음이 흔히 발생하며 이 잡음을 적절히 제어하지 않을 경우 해가 급속히 발산하게 된다. 본 연구에서는 계산 중간과정에 주기적으로 적용하여 수치잡음을 제거하기 위한 세가지 형태의 저파수통과 필터(FFT 필터, 가우스 필터, 그리고 Shapiro 필터)의 특성에 대하여 고찰하였다. 경사면 파동장에 대한 기존의 수리실험 결과와 본 수치해석 결과를 비교하고 각 필터의 잡음 제거효과, 주 시그널의 보존성, 그리고 계산 소요시간에 대하여 검토하였다. 그 결과, Shapiro 필터의 매개변수(필터 요소수와 통과수, 그리고 필터적용주기)를 적절히 설정함으로써 계산의 정확성과 효율성을 잘 달성할 수 있는 것으로 나타났다. 적정한 매개변수 선정을 위해서는 다소의 시행착오적 계산이 요구되나 대체적으로 필터 요소수 4에 대하여 50이내의 필터 통과수와 $100{\sim}200$ 시간스텝 정도의 적용주기가 타당한 것으로 판단된다.

• ETRI Journal
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• 제33권4호
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• pp.641-644
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• 2011

In this letter, we propose a novel bitrate control, using both Kalman and FIR filters, based on a Hamiltonian analysis with respect to the amount of bits from each macroblock, in an encoding of a general video codec such as H.264/AVC. Since the proposed bitrate control is based on the simple computation of an optimal control method based on the Hamiltonian analysis, it is not necessary to use additional computation, such as a DCT or quantization, to estimate the bits for bitrate control. As a result, the proposed algorithm can be applied to single-pass encoding and can provide sufficient encoding speed with respect to various applications, even those requiring real-time control.

• 한국신뢰성학회지:신뢰성응용연구
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• 제9권3호
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• pp.233-248
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• 2009

PAM(Power Amplifier Module) is the important part of a mobile phone transmitter. It amplifies the strength of signal transmitting from a mobile phone to base stations enough to resist noise or interference. In this paper reliability assessment criteria for the PAM are established in terms of quality certification test and lifetime test. The former quality certification test comprises general performance test and environmental test. Items which pass the test undergo lifetime test which guarantees the extent of mean lifetime with certain confidence.