• 한국컴퓨터산업교육학회:학술대회논문집
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• 한국컴퓨터산업교육학회 2003년도 제4회 종합학술대회 논문집
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• pp.99-102
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• 2003

Data acquisition of biomedical signal is important that can convert health of human body to measurable datas. In this paper, we developed system that can send multiple ECG data, ECG signal in biomedical signals, using Bluetooth wireless transmission. Developed system has several features, total gain of 1000, filtering data for noise reduction in hardware / software parts, portable to carry cause it has small size and battery operation. And system was designed which can measures data in several OS(Windows 2000, Windows CE).

• 대한전자공학회논문지
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• 제22권5호
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• pp.45-49
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• 1985

자동이득 제어장치에서 신호대잡음비가 큰 신호나 중첩신호(ova.lapped signal)인 경우, 장치의 출력단에서 신호 감쇄가 일어나게 된다. 이런 문제점을 해결하기 위해 guasi-noise alone reference (QNAR)알고리즘이 발표 되었다. 그러나 이 QNAR 알고리즘을 계산의 복잡성 때문에 real time processing 이 어려운 단점을 가지고 있다. 본 논문에서는 이 문제점을 해결 하기위해 새로운 방법 즉 QNAR-Bl알고리즘을 제시 하였다. 제시된 QNAR-Bl 알고리즘은 계산의 복잡성을 대폭 감소시키면서도, 시abf레이션 결과 성능은 기존의 QNAR 알고리즘 보다 향상 되었다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1993년도 춘계학술대회
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• pp.109-113
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• 1993

In this paper, we devised a simple portable digital recorder for a day life ECG signal recording. The system are consisted of ECG amp. part, signal conditioning part. A/D converter, data compression part and digital memory part. An ADPCM algorithm used at data compress part for 50% of data reduction. The maximum lengths of recording times take 3 hours in 1 mega byte memory.

• ETRI Journal
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• 제33권2호
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• pp.176-183
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• 2011

This paper presents a new analytical approach and experimental verification for the improvement of noise performance in phased-array receivers. For analysis purposes, a multi-channel array system is converted into an equivalent single-channel system, such that the two presents the identical signal and noise powers at the output, respectively. We define an effective gain, noise figure, and signal-to-noise ratio in the equivalent system. Through the proposed approach, the noise performance of the array receiver is analyzed in a general and straightforward manner and then compared to that of each individual array channel. In addition, the phase noise of the array system is analyzed in a rigorous manner, showing its effective reduction by a factor of the array size. The predicted improvement of the noise performance is experimentally confirmed with a CMOS integrated phased-array receiver.

• The Journal of the Acoustical Society of Korea
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• 제18권2E호
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• pp.45-52
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• 1999

This paper presents the integrated speech enhancement system for hands-free mobile communication. The proposed integrated system incorporates both acoustic echo cancellation and engine noise reduction device to provide signal enhancement of desired speech signal from the echoed plus noisy environments. To implement the system, a delayless subband adaptive structure is used for acoustic echo cancellation operation. The NLMS based adaptive noise canceller then applied to the residual echo removed noisy signal to achieve the selective engine noise attenuation in dominant frequency component. Two sets of computer simulations are conducted to demonstrate the effectiveness of the system; one for the fixed acoustical environment condition, the other for the robustness of the system in which, more realistic situation, the acoustic transmission environment change. Simulation results confirm the system performance of 20-25dB ERLE in acoustic echo cancellation and 9-19 dB engine noise attenuation in dominant frequency component for both cases.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.269-269
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• 2013

Redox cycling in between the two working electrodes in an electrochemical cell can lead a great signal enhancement. In this work, we report on a systematic examination of current amplification along with the decrease in the gap distance of a nanogap device which was fabricated by the combination of photo and chemical lithography [1]. The gap distance was controlled by the chemical lithographic process of surfacecatalyzed growth of metallic layer on pre-defined electrodes with wider initial gap. Enhancement of the redox current of ferri/ferrocyanide was observed upon gap distance reduction and the current is amplified about a thousand times in this redox system when the gap distance was decreased from 200 nm to 30 nm. The experimental results were discussed on the basis of the cyclic voltammetry (CV), atomic force microscopy (AFM) and scanning electron microscopy (SEM).

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.22.1-22
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• 2001

In this paper we present Multiple-Channel Active Noise Control[ANC] system by employing Independent Component Analysis[ICA] and Adaptive Network Fuzzy Inference System[ANFIS]. ICA is widely used in signal processing and communication and it use prewhiting and appropriate choice of non-linearities, ICA can separate mixed signal. ANFIS controller is trained with the hybrid learning algorithm to optimize its parameters for adaptively canceling noise. This new method which minimizes a statistical dependency of mutual information(MI) in mixed low frequency noise signal and there is no need to secondary path modeling. The proposed implementations achieve more powerful and stable noise reduction than Filtered-X LMS algorithms which is needed for LTI assumption and precise secondary error

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.203-204
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• 2008

A novel method using scaling down and restoration to reduce the PAPR of OFDM signal is proposed. This method shows a better BER performance than clipping method. And also the throughput efficiency is better than SLM.

• 한국통신학회논문지
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• 제34권8A호
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• pp.583-591
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• 2009

높은 PAPR을 갖는 직교 주파수 분할 다중 접속 신호는 비선형 왜곡을 발생시키거나, 송신기의 전력 증폭기의 효율을 나쁘게 한다. 그래서 비선형 왜곡을 줄이기 위한 상호 변조 왜곡 저감 기법이 제안되었다. IMD 저감 기법은 비선형 왜곡에 대하여 PAPR 저감 기법보다 비트 오차율 작게 한다. 하지만 IMD 저감 기법의 결정 기준은 주파수 영역에서 이루어지기 때문에 송신기에 FFT가 추가되어 시스템 복잡도가 증가하고, IMD 연산의 복잡한 계산 과정과, 이에 따른 처리시간이 증가하는 문제가 있다. 그러므로 본 논문에서는 이러한 기존의 IMD 저감 기법의 복잡도와 계산량 저감하기 위한 새로운 방식의 IMD 저감 방식을 제안한다. 또한 본 논문에서는 제안된 방식을 PTS 방식의 OFDM 통신 시스템에 적용하여 기존의 기법과 복잡도와 계산량을 비교한다. 제안된 기법은 PAPR처럼 시간영역에서 IMD의 전력량을 계산하므로 송신기에서 시스템의 복잡도와 계산량을 크게 줄일 수 있다. 또한 새로운 기법은 기존 방식과 BER 성능 면에서 차이를 보이지 않는다.

• 대한조선학회논문집
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• 제42권4호
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• pp.421-426
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• 2005

Scattering center extraction schemes for radar cross section reduction of large complex targets, like warships, was developed, which are an 1-D radar image method(range profile), and a direct analysis based on an object precision method. The analysis result of partial dihedral model shows that the presented direct analysis method is more efficient than the 1-D radar image method for scattering center extraction of interested targets, in terms of radar cross section reduction design, not signal processing. In order to verify the accuracy of the direct analysis method, a scattering center analysis of an naval weapon system was carried out, and the result was coincident with that of another well-known RCS analysis program. Finally, an analysis result of RCS and its scattering center of an 120m class warship-like model presented that the direct analysis method can be an efficient and powerful tools for radar cross section reduction of large complex targets.