• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.317-319
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• 1996

In this paper, an active vibration control system using a voice coil type linear oscillating actuator(LOA) is studied to suppress structural vibration. Being compared with a hydraulic actuator, a LOA has simplified structure and requires a few elements in the driving system, so it has lots of merits with respect to economics and maintenance. The general mathematical dynamic model to obtain the algorithm for the realization of vibration active control system is treated. Actually, the performance test of the control system using LOA is carried out on a steel test structure under sinusoidal and white noise excitation. From this test it is conformed that acceleration level of test structure is reduced near the resonance region. In the future research on the application to large structures will be studied.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
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• pp.181-183
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• 2003

본 연구에서는 현재 국내-외 논문을 참조하여 배전계통에 적용된 조류계산 알고리즘의 적용사례를 조사하였다. 배전계통에 적용된 조류계산알고리즘은 Power Summation Method와 Current Summation Method가 있다. 배전계통은 선로의 구조가 거의 대부분 방사상으로 성되어 있기 때문에 Newton Raphson, Gauss Seidel, Fast Decoupled 방법을 그대로 사용하기는 문제가 있다. 그래서 DistFlow, Forward/Backward sweeping 법 등이 주로 사용되어 왔다. 그러나 미래의 계통은 현재와는 또 다른 Topology로 방사상과 루프가 혼합된 형태로 다르게 구성되어야 할 것이다. 이러한 상황에서 미래의 배전계통에 대하여 적용 가능한 알고리즘을 전망하고져 한다.

• 한국해안해양공학회지
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• 제8권1호
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• pp.18-27
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• 1996

표층으로 방류되는 온배수의 거동을 효율적으로 해석하기 위하여 실시된 본 연구에서는 근역의 특성을 전문가 기법이 응용된 CORMIX3로부터 주변수 유동장의 변화를 고려하여 노출하였고, 이 결과를 원역모형인 2차원의 유한요소모형에 patch형태로 격자체계상에 위치시킨 후 Gaussian puff 개념을 도입하여 해석하였다. 실제의 임해발전소를 대상으로 하여 4회에 걸쳐 관측된 현장자료를 분석하여 연직 및 수평적인 표층온수의 방출특성을 면밀히 살펴보았고, 본 연구에서 제시한 방법을 적용하여 측정치와 비교한 결과 근역에서 뿐만 아니라 원역에서도 본 방법에 의하여 계산된 결과가 관측치와 거의 일치되는 매우 만족스러운 결과를 얻을 수 있었다. 배출 인근의 근역을 l0m내외로 이산화한 유한요소모형과 근역특성이 결합되어 초기 제모멘텀과 주변 유동장에 의하여 매우 불규칙한 온배수의 분포특성이 전역에 걸쳐 해석됨으로써 본 연구에서 제시한 방법이 온배수확산 거동해석에 경제적으로 적용되어 질 수 있다.

• International Journal of Automotive Technology
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• 제8권5호
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• pp.583-591
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• 2007

This paper describes the development of the $H_{\infty}$ lateral control system for an autonomous ground vehicle operating a limited area using the RTK-DGPS(Real Time Kinematic-Differential Global Positioning System). Before engaging in autonomous driving, map data are acquired by the RTK-DGPS and used to construct a reference trajectory. The navigation system contains the map data and computes the reference yaw angle of the vehicle using two consecutive position values. The yaw angle of the vehicle is controlled by the $H_{\infty}$ controller. A prototype of the autonomous vehicle by the navigation method has been developed, and the performance of the vehicle has been evaluated by experiment. The experimental results show that the $H_{\infty}$ controller and the RTK-DGPS based navigation system can sufficiently track the map at low speed. We expect that this navigation system can be made more accurate by incorporating additional sensors.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 추계학술대회
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• pp.118-121
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• 1996

This paper describes ECG signal labeling based on Fuzzy clustering, which is necessary at automated ECG diagnosis. The NPPA(Non parametric partitioning algorithm) compares the correlations of wave forms, which tends to recognize the same wave forms as different when the wave forms have a little morphological variation. We propose to apply Fuzzy clustering to ECG QRS Complex labeling, which prevents the errors to mistake by using If-then comparision. The process is divided into two parts. The first part is a parameters extraction process from ECG signal, which is composed of filtering, QRS detection by mapping to a phase space by time delay coordinates and generation of characteristic vectors. The second is fuzzy clustering by FCM(Fuzzy c-means), which is composed of a clustering, an assessment of cluster validity and labeling.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 추계학술대회
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• pp.217-220
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• 1996

In this paper, we compare three mehods to obtain PSD of HRV - FFT, AR modeling, and residual integration. Using these methods we speculate the balances of the LP and HF powers of HRV at $0^{\circ}$, $45^{\circ}$, $90^{\circ}$ tilt levels of head-up tilt table for young and healthy 24 men. R peaks are located at the highest point of QRS complex detected from modified spacial velocity algorithm. In general FFT is the most fast way to obtain PSD but PSD from FFT has too many peaks and valleies. AR PSD can show frequency of ANS activity effectively but LF component of PSD is often invisible due to interference of VLF power. The residual integration method that decomposes the AR PSD is very efficient way to extract LF component. Applying the above three methods to HRV we can visualize the trend of PSD variations along tilt levels.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 춘계학술대회
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• pp.298-302
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• 1996

The representative beat with high SNR could be obtained by the signal averaging, correct and fast detection of significant points and waveform boundary could be obtained by adoption of search interval. All experimental results of waveform boundary were compared with CSE database which had the 5 referees results and 11 ECG measurement programs. All results were within tolerance made by referees, especially the end point of T wave were more close to the referee's results than other 11 measurement programs. The diagnosis parameters that might be used in the Minnsota code criteria were extracted from the representative beat. The diagnostic classification were fulfilled using Minnsota code criteria. Through the comparison on the diagnosis results from designed automated ECG analyzer(YECGA) and the results ECG analyzer manufactured by Fukuda denshi(FCG-2201) in Japan, reliance of the performance on designed system(YECGA) could be validated.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 춘계학술대회
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• pp.288-292
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• 1996

This paper describes far the detection of heart event that is, QRS complex and P wave which are result from heart activity. The proposed QRS detection method by using the spatial velocity was identified as having the 99.6% detection accuracy as well as fast processing time. Atrial flutter, coupled P wave, and noncoupled P wave as well as atrial fibrillation could be detected correctly by three different algorithms according to their origination farm. About 99.6% correction accuracy coupled P wave could be obtained and we could be found that most detection errors are caused by establishing wrong search interval.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 춘계학술대회
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• pp.283-287
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• 1996

This paper described the estimator and eliminator far three kinds of artifacts in electrocardiogram. The most efficient estimation of baseline drift could be obtain in the cubic spline interpolation method with the PQ and TP segment which are considered to be isoelectric, from the experimental results obtained from the applied 4 types of algorithms. The time loss and distortion could be avoided with the aid of detection criteria by checking if baseline drifts exist or not. The AIEF proposed in this paper was verified as having the best removal performance with less distortion in the QRS complex through the comparison of 5 proposed algorithms. furthermore, the AIEF are most suitable far the ECG analyzer which was only needed relatively short time data due to the fast conversion into the stable state. The proposed parabolic filter with 11 points width was identified as having the best performance for the elimination of muscle artifacts. Also we could obtain 99.7% detection accuracy of spike component and minimize the error identifying QRS complex as spike.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 춘계학술대회
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• pp.320-324
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• 1996

Digital fetal monitoring system based on the personal computer combined with the digital signal processing board was implemented. The DSP board acquires and digitally processes ultrasound fetal Doppler signal for digital rectification, FIR filtering, autocorrelation function calculation, its peak detection and MEDIAN filtering. The personal computer interfaced with the DSP board is in charge of graphic display, hardcopy, data transmission and on-line analysis of fetal heart rate change including and variability. I used a recursive technique for autocorrelation function computation method and MEDIAN filter which can greatly reduce the amount of calculation and accuracy. I also implemented analysis algorithm of fetal heart rate change based on normal fetal sample data in order to exact diagnosis.