• Water for future
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• v.28 no.1
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• pp.81-90
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• 1995

This study attempts to develop a stochastic system model for extension and prediction of monthly runoff series in river basins where the observed runoff data are insufficient although there are long-term hydrometeorological records. For this purpose, univariate models of a seasonal ARIMA type are derived from the time series analysis of monthly runoff, monthly precipitation and monthly evaporation data with trend and periodicity. Also, a causual model of multiple input-single output relationship that take monthly precipitation and monthly evaporation as input variables-monthly runoff as output variable is built by the cross-correlation analysis of each series. The performance of the univariate model and the multiple input-output model were examined through comparisons between the historical and the generated monthly runoff series. The results reveals that the multiple input-output model leads to the improved accuracy and wide range of applicability when extension and prediction of monthly runoff series is required.

• Journal for History of Mathematics
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• v.26 no.2_3
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• pp.163-176
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• 2013

This study concerns Stanojevic's academic works on the $\mathfrak{L}^1$-convergence of Fourier series from 1973 to 2002. We review his academic works. Also, we briefly investigate a simple academic lineage for the researchers of $\mathfrak{L}^1$-convergence of Fourier series until 2012. First, we introduce the classical lineage of the researchers for $\mathfrak{L}^1$-convergence Fourier series in section 2. Second, we investigate the backgrounds of Stanojevic's study at Belgrade University and University of Missouri-Rolla respectively. Finally, we compare and consider the $\mathfrak{L}^1$-convergence theorems of Stanojevic's results from 1973 to 2002 successively. In addition, we compose a the simple lineage of $\mathfrak{L}^1$-convergence of Fourier series from 1973 to 2012.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.294-297
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• 2005

Time series are comprehensively appeared and developed in many applications, ranging from science and technology to business and entertainrilent. Similarity search under time warping has attracted much interest between the time series in the large sequence databases. DTW (Dynamic Time Warping) is a robust distance measure and is superior to Euclidean distance for time series, allowing similarity matching although one of the sequences can elastic shift along the time axis. Nevertheless, it is more unfortunate that DTW has a quadratic time. Simultaneously the false dismissals are come forth since DTW distance does not satisfy the triangular inequality. In this paper, we propose an efficient range query algorithmbased on a new similarity search method under time warping. When our range query applies for this method, it can remove the significant non-qualify time series as early as possible before computing the accuracy DTW distance. Hence, it speeds up the calculation time and reduces the number of scanning the time series. Guaranteeing no false dismissals, the lower bounding function is advised that consistently underestimate the DTW distance and satisfy the triangular inequality. Through the experimental result, our range query algorithm outperforms the existing others.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.426-429
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• 2004

To reconstruct the 3-D information of a irregular object, this paper proposes a new method applying the composition focus measure to time-series image. A focus measure function is carefully selected because a focus measure is apt to be affected by the working environment and the characteristics of an object. The proposed focus measure function combines the variance measure which is robust to noise and the Laplacian measure which, regardless of an object shape, has a good performance in calculating the focus measure. And the time-series image, which considers the object shape, is proposed in order to efficiently applying the interesting window. This method, first, divides the image frame by the window. Second, the composition focus measure function be applied to the windows, and the time-series image is constructed. Finally, the 3-D information of an object is reconstructed from the time-series images considering the object shape. The experimental results have shown that the proposed method is suitable algorithm to 3-D reconstruction of an irregular object.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.1
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• pp.140-145
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• 2005

The existing analytical expression for the voltage between the power and ground plane consist of metal-dielectric-metal board is expressed in the two dimensional infinite series. To reduce the computation time, the two dimensional infinite series is converted to the one dimensional infinite series using the summation formula of Fourier series. We applied these equations to the analysis of voltage between the $9‘{\times}4'$ size power-ground plane. The derived one dimensional infinite series shows the more rapid convergency and the more accurate result than the two dimensional infinite series. This equation can be applied to the power-ground plane analysis which needs a lot of the repeating computation.

• Journal of the Korea Convergence Society
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• v.6 no.4
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• pp.161-167
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• 2015

It is very difficult to predict time-series data. This is because data obtained from the signal having a non-linear characteristic has an uncertainty. In this paper, By differentiating time-series data is the average of the past data under the premise that change depending on what pattern, and find the soft look of time-series change pattern. This paper also apply the probability variables to generalize time-series data having a specific data according to the reflection ratio of the differentiation. The predicted value is estimated by removing cyclic movement and seasonal fluctuation, and reflect the trend by extracting the irregular fluctuation. Predicted value has demonstrated the superiority of the proposed algorithm and compared with the best results by a simple moving average and the moving average.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.3
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• pp.258-264
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• 2001

In this paper, a new control strategy of a series active power filter suing direct compensating voltage extraction method is proposed. The proposed series active power filter and shunt passive filters are used 3-phase 3-wire power system with nonlinear load. The series active power filter complements drawbacks of the shunt passive filter and contributes to a source side harmonic reduction. We can extract the compensating voltage of the series active power filter using performance function without phase transformations. Therefore, the calculating time is short and the control method is simple compared with conventional methods. Experimental results verify that the system using the proposed method appears a good performance.

• Journal of Power Electronics
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• v.16 no.4
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• pp.1426-1437
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• 2016

In different industrial and mission oriented applications, redundant or standby semiconductor systems can be implemented to improve the reliability of power electronics equipment. The proper structure for implementation can be one of the redundant or standby structures for series or parallel switches. This selection is determined according to the type and failure rate of the fault. In this paper, the reliability and the mean time to failure (MTTF) for each of the series and parallel configurations in two redundant and standby structures of semiconductor switches have been studied based on different failure rates. The Markov model is used for reliability and MTTF equation acquisitions. According to the different values for the reliability of the series and parallel structures during SC and OC faults, a comprehensive comparison between each of the series and parallel structures for different failure rates will be made. According to the type of fault and the structure of the switches, the reliability of the switches in the redundant structure is higher than that in the other structures. Furthermore, the performance of the proposed series and parallel structures of switches during SC and OC faults, results in an improvement in the reliability of the boost dc/dc converter. These studies aid in choosing a configuration to improve the reliability of power electronics equipment depending on the specifications of the implemented devices.

• International Journal of Advanced Culture Technology
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• v.8 no.3
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• pp.216-222
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• 2020

The purpose of this study was to predict the performance of female weightlifters using time series analysis. Based on this purpose, a time series analysis was used to calculate the performance prediction model for women(58kg) among the domestic women weightlifters who participated in the Olympics. As a result of creating time series data based on 10 years of record and then evaluating the sequential charts of each athlete group, the female athletes' records did not show any seasonality or difference. In addition, after examining the independence of the data through the creation of a time series model, it was shown that the models produced conformed to the criteria for compliance and that there was no difference in the data, but there was a trend. Accordingly, Holt linear trend analysis of the exponential smoothing model was applied. As a result of deriving the prediction model of the athletes through this process, it was found that the women (58kg) who participated in the Olympics continued to improve within the range of 166.11kg to 184.1kg.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.11
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• pp.1458-1469
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• 2004

In this study, color names focusing on the purple series, appearing in the clothing of the Joseon Dynasty, were classified systematically, and the conceptual meaning of each name were investigated through various methods. The results are as follows; First, the color names of purple-series were classified systematically. According to the integration scheme of morphemes, color names could be divided into two categories; single names and composite names. Color names could also be classified into universal and limited names according to the areal distribution of literatures. Secondly, the conceptual meaning of the color names of purple-series were considered. The conceptual meaning could be divided into two categories; one 'etymological and dyeing methodological meaning', the other 'color systematic meaning' By studying the dictionary definition of color names, comparing and analyzing the material composition of colors, the etymological and dyeing methodological meaning could be grasped. Furthermore, the color systematic meaning of each name could be grasped through the cluster analysis of L*, a*, b* values measured from the relics of clothing. Thirdly, the conceptual semantic structure were established on the basis of conceptual meanings of purple-series color names. The conceptual semantic structure of purple-series color names is forming discrete structure with the dyeing method and material of dyes as their semantic components.