• KIPS Transactions on Software and Data Engineering
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• v.10 no.3
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• pp.79-84
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• 2021

A feature extraction method capable of reflecting features well while mainaining the properties of data is required in order to process high-dimensional data. The principal component analysis method that converts high-level data into low-dimensional data and express high-dimensional data with fewer variables than the original data is a representative method for feature extraction of data. In this study, we propose a principal component analysis method based on adaptive correlation when selecting principal component variables in principal component analysis for data feature extraction when the data is high-dimensional. The proposed method analyzes the principal components of the data by adaptively reflecting the correlation based on the correlation between the input data. I want to exclude them from the candidate list. It is intended to analyze the principal component hierarchy by the eigen-vector coefficient value, to prevent the selection of the principal component with a low hierarchy, and to minimize the occurrence of data duplication inducing data bias through correlation analysis. Through this, we propose a method of selecting a well-presented principal component variable that represents the characteristics of actual data by reducing the influence of data bias when selecting the principal component variable.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.2A
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• pp.383-390
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• 2006

In this paper, a stochastic field that is compatible with Monte Carlo simulation is suggested for an expansion-based stochastic analysis scheme of weighted integral method. Through investigation on the way of affection of stochastic field function on the displacement vector in the series expansion scheme, it is noticed that the stochastic field adopted in the weighted integral method is not compatible with that appears in the Monte Carlo simulation. As generally recognized in the field of stochastic mechanics, the response variability is not a linear function of the coefficient of variation of stochastic field but a nonlinear function with increasing variability as the intensity of uncertainty is increased. Employing the stochastic field suggested in this study, the response variability evaluated by means of the weighted integral scheme is reproduced with high precision even for uncertain fields with moderately large coefficient of variation. Besides, despite the fact that only the first-order expansion is employed, an outstanding agreement between the results of expansion-based weighted integral method and Monte Carlo simulation is achieved.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.213-216
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• 2001

The H.263 Annex I method for the intraframe coding is based on the prediction in DCT domain, unlike JPEG, MPEG-1, and MPEG-2 where the intraframe coding uses block DCT, independent of the neighboring blocks. In this paper, we show the ineffectiveness of H.263 Annex I prediction method by mathematically deriving the spatial domain meaning of H.263 Annex I prediction method. Based on the derivation, we propose a prediction method which is based on the spatial correlation property of image signals. From the experiment and derivation, we verified the proposed method.

• The Journal of the Acoustical Society of Korea
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• v.17 no.2E
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• pp.31-37
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• 1998

This paper proposes a feature extraction method using wavelet transform for speech recognition. Speech recognition system generally carries out the recognition task based on speech features which are usually obtained via time-frequency representations such as Short-Time Fourier Transform (STFT) and Linear Predictive Coding(LPC). In some respects these methods may not be suitable for representing highly complex speech characteristics. They map the speech features with same may not frequency resolutions at all frequencies. Wavelet transform overcomes some of these limitations. Wavelet transform captures signal with fine time resolutions at high frequencies and fine frequency resolutions at low frequencies, which may present a significant advantage when analyzing highly localized speech events. Based on this motivation, this paper investigates the effectiveness of wavelet transform for feature extraction of wavelet transform for feature extraction focused on enhancing speech recognition. The proposed method is implemented using Sampled Continuous Wavelet Transform (SCWT) and its performance is tested on a speaker-independent isolated word recognizer that discerns 50 Korean words. In particular, the effect of mother wavelet employed and number of voices per octave on the performance of proposed method is investigated. Also the influence on the size of mother wavelet on the performance of proposed method is discussed. Throughout the experiments, the performance of proposed method is discussed. Throughout the experiments, the performance of proposed method is compared with the most prevalent conventional method, MFCC (Mel0frequency Cepstral Coefficient). The experiments show that the recognition performance of the proposed method is better than that of MFCC. But the improvement is marginal while, due to the dimensionality increase, the computational loads of proposed method is substantially greater than that of MFCC.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.15 no.2
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• pp.186-194
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• 2008

Purpose: The purpose of this studγ is to understand relations among perceived stress, stress coping method, self-rare behavior and Hemoglobin $A_1c$ of elderly diabetic mellitus patients. Method: Participants were 128 patients who were under medical treatment in outpatient department at C university hospital. The collected data were analyzed using technical statistics, frequency, percentage, T-test, ANOVA and person's correlation coefficient by SPSS 12.0. Result: There were positive correlation between self-care behavior and coping method based on emotions under the lower category of stress coping method. Hemoglobin $A_1c$ of patients had a negative correlation with physical exorcise of self coping method under the lower category. Perceived stress had also a negative correlation with emotions as coping method in the lower category and medication of self-care behavior. Conclusion: It was noted that elderly diabetic mellitus patients didn't much use a coping method based mainly problems and another method based emotions in case of perceived stress. The findings of this study will be useful for developing an nursing intervention program focused on elderly diabetic mellitus patients.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.292-296
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• 2008

A new method of evaluating critical damage values of commercial materials is presented in this paper. The method is based on the previous study of the methodology [1] of acquisition of true stress-strain curves or flow stress curves over large strain from the tensile test in which the flow stress is described by the Hollomon law-like form, that is, by the strain dependent strength coefficient and the strain hardening exponent. The strain hardening exponent is calculated from the true strain at the necking point to meet the Considere condition. The strength coefficient is assumed to be constant before necking and represented by a piecewise linear function of strain after necking. With the predicted flow stress, a tensile test is simulated by a rigid-plastic finite element method with higher accuracy of less than 0.5% error between experiments and predictions. The instant when the fracture begins and thus the critical damage is obtained is determined by observing the stress variation at the necked region. It is assumed that the fracture due to damage begins when the pattern of stress around the necked region changes radically. The method is applied to evaluate the critical damage of a low carbon steel.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.4
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• pp.383-389
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• 2011

The negative fishery factors from an environmental perspective are greenhouse gas emissions due to high fossil fuel use, destruction of underwater ecosystems by bottom trawls, a reduction in resources by fishing, and damage to ecosystem diversity. In particular, the greenhouse gas emissions from fisheries is an important issue based on the Cancun meeting in Mexico in 1992 and the Kyoto protocol in 2005. However, no investigations on the GHG emissions from Korean fisheries have been conducted. Therefore, a quantitative analysis of GHG emissions from the Korean fishery industry is needed as a first step to identify a method to reduce GHG emissions from fisheries. The purpose of this study was to investigate the degree of GHG emitted from fisheries. Here, we calculated the GHG emissions from four main Korean fisheries(i.e., large trawls, large purse seines, Danish seines, and bottom pair trawls) using the life cycle assessment(LCA) method. The system boundary and input parameters for each process level were defined for LCA analysis. The fuel use coefficient of each fishery was also calculated. The GHG emissions from edible seafood were calculated considering different consuming areas. The results will be helpful to understand GHG emissions from Korean fisheries.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1925-1933
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• 2017

The brushless DC motor's commutation torque ripple is caused by inconsistency in the rate of phase current change. Thus, a method that considers armature resistance is proposed to modulate phase current. The three-phase control strategy, which involves the "open-phase conduction, off-phase pulse width modulation, and maintained non-commutation phase" technique, is applied during commutation at full-speed segments of the motor. Changes in each phase current are analyzed theoretically by establishing mathematical model based on phase current to determine the relative difference among shutdown phase, duty, and motor operating parameters. The turn-on and turn-off phase current change rates are made to be consistent to ensure less non-commutation phase current ripple, then the torque ripple is inhibited. The simulation results show that the phase commutation current and torque ripple coefficient of the proposed method are reduced from 56.9% and 55.5% to 6.8% and 6.1%, respectively. In the experiment system, the pulsation coefficient of the motor phase current is reduced from 40.0% to 16.7% at low speed and 50.0% to 18.8% at high speed. The simulation and experimental results show that the proposed control method significantly inhibits commutation current and torque in the full section.

• Membrane and Water Treatment
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• v.4 no.3
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• pp.157-174
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• 2013

The present study is devoted to the validation of a new method for in line electrokinetic characterisation of deposits on membrane surfaces. This method is based upon simultaneous measurements of transversal streaming potential and permeates flux at constant pressure before and during the deposit formation. Dead-end filtration experiments were conducted with negative flat membranes forming a narrow slit channel, negative hollow fiber membranes and mono-dispersed suspensions of (negatively charged) polystyrene latex and (positively charged) melamine particles at various concentrations. It was observed that the overall streaming potential coefficient increased in absolute value with the deposited latex quantity, whereas it decreased and changed of sign during the filtration of melamine suspensions. By considering a resistance-in-series model, the streaming potential coefficient of the single deposit ($SP_d$) was deduced from the electrokinetic and hydraulic measurements. The independence of $SP_d$ with respect to growth kinetics validates the measurement method and the reliability of the proposed procedure for calculating $SP_d$. It was found that $SP_d$ levelled off much more quickly when filtration was performed through the slit channel. This different behaviour could result from a non-uniform distribution of the deposit thickness along the membrane given that the position of measuring electrodes is different between the two cells.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.6
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• pp.1361-1368
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• 2009

This study attempts to present investment priorities and select industry for regional economic reinvigorating by analysing regional inter-industry of Chungchong area(including Chungnam and Chungbuk region) After the regional inter-industry table of Chungchong area has been made using a location quotient(LQ) method based on national inter-industry table of 2006 derived from national inter-industry table of 2003 using RAS method, various kind of impacts to Chungchong area are analysed. Manufacturing has the highest result in the result of production-inducing effect and value-added-inducing effect and hotels and restaurants has the highest result in employ-inducing effect. Sensitivity coefficient is highly analysed in mining and quarrying and influential coefficient is highly analysed in manufacturing.