• Journal of Information Processing Systems
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• 제16권3호
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• pp.588-598
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• 2020

An alternative state estimation filtering algorithm is designed for continuous time systems with noises as well as control input. Two kinds of estimation filters, which have different measurement memory structures, are operated selectively in order to use both filters effectively as needed. Firstly, the estimation filter with infinite memory structure is operated for a certain continuous time system. Secondly, the estimation filter with finite memory structure is operated for temporarily uncertain continuous time system. That is, depending on the presence of uncertainty, one of infinite memory structure and finite memory structure filtered estimates is operated selectively to obtain the valid estimate. A couple of test variables and declaration rule are developed to detect uncertainty presence or uncertainty absence, to operate the suitable one from two kinds of filtered estimates, and to obtain ultimately the valid filtered estimate. Through computer simulations for a continuous time aircraft engine system with different measurement memory lengths and temporary model uncertainties, the proposed state estimation filtering algorithm can work well in temporarily uncertain as well as certain continuous time systems. Moreover, the proposed state estimation filtering algorithm shows remarkable superiority to the infinite memory structure filtering when temporary uncertainties occur in succession.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.6-7
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• 2018

In the previous study, durometer, namely rubber hardness tester Was used to confirm the possibility of using the setting time of concrete for determination. in this study, the possibility of using condensation time judgment condensation estimation system by comparing the measuring station setting estimation system Measuring needle of the proctor penetration resistance tester by newly making a measurement needle and refining the coagulation estimation system Want to make sure. As a result of this study, it was possible to use one condensation estimation system showing similar correlation between the two types of durometer showing high correlation with the penetration resistance value of proctor testers, It is considered to be fruitful to use the dew condensation estimation system for determining the setting time.

• 전기학회논문지P
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• 제59권2호
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• pp.202-205
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• 2010

In this paper, mechanical reliability(Life-time) estimation method for 25.8kV SIS(Solid Insulated Switchgear) has been studied. Recently enacted KEPCO's standard includes clause that have to submit a warrantable reliability data for life-time(over B10 25 years) of an epoxy-solid insulating material. Accordingly, this research was carried out on the ALT(Accelerated Life Test) and Life-Estimation method for SIS's insulating material. Mechanical life-time estimation for SIS's insulating material is to verify reliability for tensile creep & fatigue stress, which is the major mechanical stress of SIS. This study proved that SIS's reliability for mechanical stress and established that confidence for estimation results in further verification test.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1129-1134
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• 2006

Mass estimation was derived as functions of acceleration magnitude and primary frequency. The conventional method of mass estimation used frequency data directly in the frequency domain. The signals that can be obtained sensor contained noise as well as impact signal. Therefore, how well we can detect the frequency data in noise directly determines the quality of mass estimation. To find exact frequency data, we used time-frequency analysis. The time frequency method are expected to be more useful than the conventional frequency domain analyses for the mass estimation problem on a plate type structure. Also it has been concluded that the smoothed WVD can give more reliable means than the other methodologies for the mass estimation in a noisy environment.

• 한국소음진동공학회논문집
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• 제16권8호
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• pp.872-878
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• 2006

Mass estimation was derived as functions of acceleration magnitude and primary frequency. The conventional method of mass estimation used frequency data directly in the frequency domain. The signals that can be obtained sensor contained noise as well as impact signal. Therefore, how well we can detect the frequency data in noise directly determines the quality of mass estimation. To find exact frequency data, we used time-frequency analysis. The time-frequency methods are expected to be more useful than the conventional frequency domain analyses for the mass estimation problem on a plate type structure. Also it has been concluded that the smoothed WVD can give more reliable means than the other methodologies for the mass estimation in a noisy environment.

• 대한의용생체공학회:의공학회지
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• 제26권2호
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• pp.87-93
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• 2005

A new method for real-time estimating left ventricular relaxation time constant (T) from the left ventricular (LV) pressure waveform, based on the isovolumic relaxation model, is proposed. The presented method uses a recursive least squares (RLS) algorithm to accomplish real-time estimation. A new criterion to detect the end-point of the isovolumic relaxation period (IRP) for the estimation of T is also introduced, which is based on the pattern analysis of mean square errors between the original and reconstructed pressure waveforms. We have verified the performance of the new method in over 4,600 beats obtained from 70 patients. The results demonstrate that the proposed method provides more stable and reliable estimation of τ than the conventional 'off-line' methods.

• International journal of advanced smart convergence
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• 제4권2호
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• pp.46-53
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• 2015

This paper suggests a method of real time confidence interval estimation to detect abnormal states of sensor data. For real time confidence interval estimation, the mean square errors of the exponential smoothing method and moving average method, two of the time series analysis method, were compared, and the moving average method with less errors was applied. When the sensor data passes the bounds of the confidence interval estimation, the administrator is notified through alarms. As the suggested method is for real time anomaly detection in a ship, an Android terminal was adopted for better communication between the wireless sensor network and users. For safe navigation, an administrator can make decisions promptly and accurately upon emergency situation in a ship by referring to the anomaly detection information through real time confidence interval estimation.

• 전자공학회논문지A
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• 제28A권5호
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• pp.347-354
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• 1991

In this paper, the Automatic Tracking Window(ATW) algorithm is applied to the Generalized Cross-Correlation(GCC) time delay estimation algorithm as a preprocessing. The Linear Prediction(LP) algorithm, which is a pararmetric spectral estimation algorithm, is applied to the time delay estimation. And the ATW, a preprocessing algorithm is applied to this algorithm too. This paper shows that the ATW algorithm attenuates the sidelobes very much and improves the resolution of the timedelay estimation.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.909-915
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• 2008

시간지연 추정 방법들에 대한 연구는 예전부터 활발히 진행되고 있다. 하지만 실제 환경에서 측정된 신호들을 이용하여 시간지연을 추정함에 있어 그 성능에 미치는 영향들에 대한 연구는 미흡한 실정이다. 1997 년에 Brandstein 과 Siverman 은 공간의 잔향 시간이 길어질수록 그 공간에서의 시간지연 추정 성능이 나빠짐을 모의 실험을 통해 밝혔다. 하지만 동일한 잔향시간을 갖는 공간에서 측정된 신호의 경우에도 시간 구간에 따라 추정 성능에 차이를 보이고 있다. 따라서 본 연구에서는 시간지연 추정 성능에 미치는 영향들에 대해서 살펴보고, 그 원인들에 대해 분석하였다. 그 결과, 동일한 잔향시간을 갖는 공간에서 측정된 신호일지라도 시간 구간에 따라 R/D 비와 신호의 특성들이 다르기 때문에 추정 성능에 차이가 나타남을 알 수 있었다.

• 제어로봇시스템학회논문지
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• 제4권1호
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• pp.76-81
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• 1998

This paper presents an on-line scheme for parameter estimation of continuous-time systems, based on the model adjustment technique and the genetic algorithm technique. To deal with the initialisation and unmeasurable signal problems in on-line parameter estimation of continuous-time systems, a discrete-time model is obtained for the linear differential equation model and approximations of unmeasurable states with the observable output and its time-delayed values are obtained for the nonlinear state space model. Noisy observations may affect these approximation processes and degrade the estimation performance. A digital prefilter is therefore incorporated to avoid direct approximations of system derivatives from possible noisy observations. The parameters of both the model and the designed filter are adjusted on-line by a genetic algorithm, A set of simulation works for linear and nonlinear systems is carried out to demonstrate the effectiveness of the proposed method.