• 대한의용생체공학회:의공학회지
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• 제43권4호
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• pp.280-289
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• 2022

In this paper, we present a QRS-complex detection algorithm to calculate an accurate heartbeat and clearly recognize irregular rhythm from ECG signals. The conventional Pan-Tompkins algorithm brings false QRS detection in the derivative when QRS and noise signals have similar instant variation. The proposed algorithm uses amplitude differences in 7 adjacent samples to detect QRS-complex which has the highest amplitude variation. The calculated amplitude is cubed to dominate QRS-complex and the moving average method is applied to diminish the noise signal's amplitude. Finally, a decision rule with a threshold value is applied to detect accurate QRS-complex. The calculated signals with Pan-Tompkins and proposed algorithms were compared by signal-to-noise ratio to evaluate the noise reduction degree. QRS-complex detection performance was confirmed by sensitivity and the positive predictive value(PPV). Normal ECG, muscle noise ECG, PVC, and atrial fibrillation signals were achieved which were measured from an ECG simulator. The signal-to-noise ratio difference between Pan-Tompkins and the proposed algorithm were 8.1, 8.5, 9.6, and 4.7, respectively. All ratio of the proposed algorithm is higher than the Pan-Tompkins values. It indicates that the proposed algorithm is more robust to noise than the Pan-Tompkins algorithm. The Pan-Tompkins algorithm and the proposed algorithm showed similar sensitivity and PPV at most waveforms. However, with a noisy atrial fibrillation signal, the PPV for QRS-complex has different values, 42% for the Pan-Tompkins algorithm and 100% for the proposed algorithm. It means that the proposed algorithm has superiority for QRS-complex detection in a noisy environment.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.58-63
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• 1998

B.Widrow established fundamental relations between the least-mean-square (LMS) algorithm and the digital Fourier transform［1］. By extending these relations, we proposed the short time spectra analysis system using the LMS algorithm［2]. In that paper, we used the normal LMS algorithm on the thought of dealing with only real analytical signal. This algorithm minimizes the real mean-square by recursively altering the complex weight vector at each sampling instant. But, the short time spectra analysis sometimes deals with the complex signal that is outputted from complex analog filter. So, in order to optimize and develop this methods, furthermore it is necessary to derive an algorithm for the complex analytical signal. In this paper, we first discuss the new adaptive system for the spectra analysis using the complex LMS algorithm and then derive convergence condition, time constant of coefficient adjustment and frequency resolution by extending the discussion. Finally, the effectiveness of the proposed method is experimentally demonstrated by applying it to the measurement of transfer performance on complex analog filter.

• 한국통신학회논문지
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• 제34권5C호
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• pp.521-526
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• 2009

In this paper, a complex-valued recursive least squares escalator filter algorithm with reduced computational complexity for complex-valued signal processing applications is presented. The local tap weight of RLS-ESC algorithm is updated by incrementing its old value by an amount equal to the local estimation error times the local gain scalar, and for the gain scalar, the local input autocorrelation is calculated at the previous time. By deriving a new gain scalar that can be calculated by using the current local input autocorrelation, reduced computational complexity is accomplished. Compared with the computational complexity of the complex-valued version of RLS-ESC algorithm, the computational complexity of the proposed method can be reduced by 50% without performance degradation. The reduced computational complexity of the proposed algorithm is even less than that of the LMS-ESC. Simulation results for complex channel equalization in 64QAM modulation schemes demonstrate that the proposed algorithm has superior convergence and constellation performance.

• The Journal of the Acoustical Society of Korea
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• 제17권1E호
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• pp.36-43
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• 1998

A fuzzy logic filter is constructed from a set of fuzzy IF-THEN rules which change adaptively to minimize some criterion function as new information becomes available. This paper generalizes the fuzzy logic filter and it's adaptive filtering algorithm to include complex parameters and complex signals. Using the complex Stone-Weierstrass theorem, we prove that linear combinations of the fuzzy basis functions are capable of uniformly approximating and complex continuous function on a compact set to arbitrary accuracy. Based on the fuzzy basis function representations, a complex orthogonal least-squares (COLS) learning algorithm is developed for designing fuzzy systems based on given input-output pairs. Also, we propose an adaptive algorithm based on LMS which adjust simultaneously filter parameters and the parameter of the membership function which characterize the fuzzy concepts in the IF-THEN rules. The modeling of a nonlinear communications channel based on a complex fuzzy is used to demonstrate the effectiveness of these algorithm.

• 전기전자학회논문지
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• 제17권2호
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• pp.145-150
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• 2013

본 논문에서 ICS(Interference Cancellation System) 중계기에서 간섭제거를 위한 새로운 CSS(Complex Signed-Signed) CMA(Constant Modulus Algorithm) 알고리즘을 제안한다. 중계기가 궤환 신호를 가질 때 CSS CMA 알고리즘은 궤환 경로로부터 간섭 신호를 제거하기 위한 디지털 신호 처리를 사용한 ICS 중계기에 대해 제안한다. 제안된 Complex Signed Signed CMA 알고리즘은 스텝 사이즈를 조절함에 따라 하드웨어 복잡도와 성능이 개선된다. 제안된 Complex Signed Signed CMA 알고리즘에서 스텝사이즈가 0.00043인 경우 수렴상태에서 평균 자승 에러는 기존 CMA 알고리즘보다 약 4dB정도 더 낮다. 그리고, 평균 자승 에러 -25dB를 기준으로 LMS(Least Mean Square)와 Signed LMS(Normalized Least Mean Square)보다 수렴회수가 1950 ~ 2150회 정도 줄어든다.

• 대한전자공학회논문지
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• 제21권5호
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• pp.55-60
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• 1984

CMOS기술의 발전에 따라 디지탈 회로를 실현하는데 complex gate 구조를 많이 사용하게 되었다. CMOS complex gate에 대해 내부 게이트 응답과 unknown state등을 고려하여 모든 stuck-open(이하 s-op)과 stuck-on(이하 s-on) 고장을 검출할 수 있는 새로운 테스트 생성 알고리즘이 제소되었다 이 알고리즘은 minimal하고 complete한 테스트 집합을 구할 수 있게 해준다. 또한, 임의의 CMOS complex gate 회로에 대해 본 알고리즘을 적용시켜, 컴퓨터를 통해 그와 같은 테스트 집합이 구해짐을 입증하였다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제3권2호
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• pp.121-135
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• 1999

This paper studies the problem of inverting minimal path sets to obtain minimal cut sets for complex system. We describe efficiency of inversion algorithm by the use of boolean algebra and we develop inclusion-exclusion algorithm and pivotal decomposition algorithm for reliability calculation of complex system. Several examples are illustrated and the computation speeds between the two algorithms are undertaken.

• 대한전기학회논문지
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• 제35권4호
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• pp.127-135
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• 1986

This paper represents a real time algorithm which improves the some drawbacks in the past methods for detection of the QRS conplexes of ECG signals. In the conventional method we can't detect QRS complex and QRS duration more correctly in case of (1) the contaminated ECG with 60Hz noise, muscle noise. (2) the movement of the baseline for a QRS complex. (3) being abnormal QRS complex with prolonging QRS. Therefore, we have proposed a new algorithm which can detect accurate QRS complex detection in case of the contaminated ECG with 60Hz noise, muscle noise, and movement of baseline for QRS complex. Moreover, in case of prolonging QRS we accomplished to detect not only QRS complex but also a single pulse that has a width proportional to QRS duration. This algorithm which is proposed in our paper in our paper in programmed with 6502 assembly language for real time ECG signal processing.

• 한국통신학회논문지
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• 제35권8A호
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• pp.760-767
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• 2010

For complex channel blind equalization, this study presents the performance and characteristics of two complex blind information theoretic learning algorithms (ITL) which are based on minimization of Euclidian distance (ED) between probability density functions compared to constant modulus algorithm which is based on mean squared error (MSE) criterion. The complex-valued ED algorithm employing constant modulus error and the complex-valued ED algorithm using a self-generated symbol set are analyzed to have the fact that the cost function of the latter forces the output signal to have correct symbol values and compensate amplitude and phase distortion simultaneously without any phase compensation process. Simulation results through MSE convergence and constellation comparison for severely distorted complex channels show significantly enhanced performance of symbol-point concentration with no phase rotation.

• 센서학회지
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• 제28권1호
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• pp.13-16
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• 2019

The analysis of electrocardiogram (ECG) signals facilitates the detection of various abnormal conditions of the human heart. The QRS complex is the most critical part of the ECG waveform. Further, different diseases can be identified based on the QRS complex. In this paper, a new algorithm based on the well-known Pan-Tompkins algorithm has been proposed. In the proposed scheme, the QRS complex is initially extracted by removing the background noise. Subsequently, the R-R interval and heart rate are calculated to detect whether the ECG is normal or has some abnormalities such as tachycardia and bradycardia. The accuracy of the proposed algorithm is found to be almost the same as the Pan-Tompkins algorithm and increases the R peak detection processing speed. For this work, samples are used from the MIT-BIH Arrhythmia Database, and the simulation is carried out using MATLAB 2016a.