• The Korean Journal of Applied Statistics
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• v.35 no.1
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• pp.119-129
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• 2022

In this paper, we predict the earthquake magnitudes which were recently occurred in Gyeongju and Pohang, using statistical methods based on historical data. For this purpose, we use the five-year block maximum data of 1392~1771 period, which has a relatively high annual density, among the historical earthquake magnitude data of the Chosun Dynasty. Then, we present the prediction and analysis of earthquake magnitudes for the return level over return period in the Chosun Dynasty using the extreme value theory based on the distribution of generalized extreme values (GEV). We use maximum likelihood estimation (MLE) and L-moments estimation for parameters of GEV distribution. In particular, this study also demonstrates via the goodness-of-fit tests that the GEV distribution can be an appropriate analytical model for these historical earthquake magnitude data.

• The Journal of the Acoustical Society of Korea
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• v.41 no.2
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• pp.143-149
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• 2022

In this paper, we evaluate the underwater frequency diversity communication performance of Selective Combination (SC) using Maximum Likelihood Estimation (MLE). In an underwater multipath frequency selective channel, destructive interference fading due to delay spread of a received signal affects the increase in error and Signal to Noise Ratio (SNR) variability of an underwater acoustic communication. Selective Combination frequency diversity using a single sensor is applied as a transmission performance improvement technique according to the frequency selectivity of a channel. In the sea experiment applying MLE for SC decision value extraction, we evaluate the performance of SC frequency diversity and MLE-SC frequency diversity. In experiment result, we confirm through experiment that the Bit Error Rate (BER) is relatively lower when the decision value extracted through MLE-SC is applied than when the SC decision value is fixed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.4
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• pp.722-727
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• 2010

This paper presents Dynamic-Simulation to estimate the inductance of a permanent magnet type transverse flux rotating motor by applying the real-time parameter estimation theory. As transverse flux rotating motor has the complex structure, it can be happen to some errors between real value and designed one with respect to the inductance. To reduce this kinds of errors, the real-time parameter estimation theory was applied to dynamic-simulation. And then, By comparing the estimated inductance and designed one, it is realized that the real-time parameter estimation theory can be applied in the permanent magnet type transverse flux rotating motor.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.4
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• pp.16-22
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• 2013

This paper presents a method to analyze the voltage sag data obtained from monitoring systems. In order to establish effective countermeasures against voltage sag problems, an assessment of the system performance with respect to voltage sags is needed. Generally, the average annual sag frequency can be estimated by using the recorded voltage sag events for several years. However, the simple average value can not give the information about the errors of estimation. Such an average estimation is not useful for establishing effective solutions for voltage sag problems. Therefore, this paper proposes an effective method based on the Interval Estimation method. The estimation of voltage sag frequency is performed by using the average frequency and Poisson probability model. The proposed method can give the expected annual sag frequency and upper one-sided bound frequency.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.7
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• pp.2480-2495
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• 2014

This paper describes a hierarchical method for image-based age estimation that combines age group classification and age value estimation. The proposed method uses a coarse-to-fine strategy with different appearance features to describe facial shape and texture. Considering the damage to continuity between neighboring groups caused by fixed divisions during age group classification, a dynamic grouping technique is employed to allow non-fixed groups. Based on the given group, an ordinal hyperplane ranking (OHRank) model is employed to transform age estimation into a series of binary enquiry problems that can take advantage of the intrinsic correlation and ordinal information of age. A set of experiments on FG-NET are presented and the results demonstrate the validity of our solution.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.8
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• pp.1444-1456
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• 2011

This paper presents a low-complexity algorithm for an H.264/AVC encoder. The proposed motion estimation scheme determines the best coding mode for a given macroblock (MB) by finding motion-blurred MBs; identifying, before motion estimation, an early selection of MBs; and hence saving processing time for these MBs. It has been observed that human vision is more sensitive to the movement of well-structured objects than to the movement of randomly structured objects. This study analyzed permissible perceptual distortions and assigned a larger inter-mode value to the regions that are perceptually less sensitive to human vision. Simulation results illustrate that the algorithm can reduce the computational complexity of motion estimation by up to 47.16% while maintaining high compression efficiency.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.178-180
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• 2001

State estimation in power system is to estimate state variable value which minimizes the error from the real state measured by the gauge and connection state of the circuit breaker. In the past, it was difficult to determine measure function considering the correlation of the measured values. In this paper, an extended state estimation is proposed to process easily various kinds of estimation variable. The proposed algorithm is developed by expanding state variable concept based on many measured values and treating correlation between estimation variable and state variable, it is considered that the state variable satisfy some limitations named "Equality Limitation conditions".

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.1073-1075
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• 1998

This paper presents the method of parameter estimation of diffusion model for monitoring Demand-Side Management Program. Bass diffusion model was applied in this paper, which has different values according to parameters ; coefficients of innovation, imitation and potential adopters. Though it is very important to estimate three parameter, there are no empirical results in practice. Thus, this paper presents the method of parameter estimation in case of few data with constraints to reduce the possibility of bad estimation. The constraints are empirical results or expert's decision. Case studies show the diffusion curves of high-efficient lighting and also forecasting of the peak value for power demand considering diffusion of high-efficient lighting, the feedback and least-square parameter estimation method used in this paper enable us to evaluate the status and forecasting of the effect of DSM program.

• Journal of the Korean GEO-environmental Society
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• v.6 no.3
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• pp.25-34
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• 2005

The governing design point of shallow foundation is not its bearing capacity but its settlemen and N-value by the SPT is one of the key parameters for settlement estimation. However, if the N-value is more than 50/30, such as 50/10 or 50/20, the N-vlaues are not blow count of 30cm depth penetration. In these cases, the estimated settlements have big difference with the measured values because the applied maximum N value for the settlement estimation is 50. Therefore, in this study, the modified method for N-value estimation is suggested. The settlements by four methods, which are based on Elastic Theory with application of modified N-value, are compared with the Origina Plate Load Test data. The same comparision was carried out with another seven Empirical Methods. The result of this study showed that the error range of settlement is decreased from 260.4~2136.5% to 20.3~272.7%. Among four methods which are based on Elastic Theory, the original method by Elastic Theory is the most accurate with the application of modified N-value. Among Empirical Methods, Terzaghi-Peck's(1948, 1967) modified method 1 is the most accurate with the application of modified N-value. The differences between the original method by Elastic Theory and Terzaghi-Peck's(1948, 1967) modified method 1 are neglectable.

• Journal of the Korean Statistical Society
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• v.35 no.1
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• pp.91-103
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• 2006

Yun (2005) introduced an estimator of the second order parameter characterizing the tail behavior of probability distributions and proved its consistency. In this paper we prove its asymptotic normality under a third order condition.