• Proceedings of the KSPS conference
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• 2003.05a
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• pp.101-104
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• 2003

The purpose of this study was to compare acoustic differences of fricative /s/ between the dysarthric subjects and normal subjects. In additional, the subjects' speeches were evaluated in terms of word intelligibility containing /s/ and perceptual severity. Acoustic parameters were duration, peak frequency and intensity of /s/. The results showed that the first peak frequency and intensity of /s/ were significantly different between dysarthric subjetcts and normal subjects. Second, peceptual parameters were significantly different between dysarthric subjetcts and normal subjects. The Pearson correlation coefficient was used to determine the relationship between the acoustical and perceptual data. The results showed that there was a strong correlation between perceptual parameters and peak frequency of /s/.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.919-922
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• 2003

The correlation between noise and vibration by a heavy-weight floor impact was studied. The triggering technique was used for increasing the reliability and stability to measure the level of sound pressure, sound intensity and vibration acceleration. The simple finite element and rigid body analysis method were suggested to calculate the natural frequencies of the multi-layer floor system. The result show that the isolation material adapted to reduce the light-weight floor impact noise, causing the natural frequency lower, make resonance with dominant driving frequency, and increase the noise level very sharply. Therefore the noise level Peak in the region of low frequency, below 63Hz, would be related with the natural frequencies of the floor system.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.10a
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• pp.582-586
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• 2004

The purpose of this study is to examine the lead-lag relationship between volatility and returns in high frequency stock market data to see the validity of two hypotheses that explain volatility asymmetry. Specifically, wavelet analysis is applied to decompose the volatility process into permanent and transitory components and then each component is investigated in conjunction with returns. The results from cross-correlation analysis between volatility and returns support the leverage effect hypothesis rather than the volatility feedback hypothesis in all cases.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7A
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• pp.628-638
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• 2005

The analysis of maximum diversity order and coding gain for multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems over time-and frequency-selective (or doubly-selective) channels is addressed in this paper. A novel channel time-space correlation function is developed given the spatially correlated doubly-selective Rayleigh fading channel model. Based on this channel-model assumption, the upper-bound of pairwise error probability (PEP) for MIMO-OFDM systems is derived under the maximum likelihood (ML) detection. For a certain space-frequency code, we quantify the maximum diversity order and deduce the expression of coding gain. In this wort the impact of channel time selectivity is especially studied and a new definition of time diversity is illustrated correspondingly

• Journal of the Korea Convergence Society
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• v.9 no.5
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• pp.15-20
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• 2018

In modern society, crime is one of the major social problems. Crime has a great impact not only on victims but also on those around them. It is important to predict crimes before they occur and to prevent crime. Various studies have been conducted to predict crime. One of the most important factors in predicting crime is frequency of crime occurrence. The frequency of crime is widely used as basic data for predicting crime. However, the frequency of crime occurrence is announced about 2 years after the statistical processing period. In this paper, we propose a frequency analysis of crime - related key words retrieved from the web as a way to indirectly grasp the frequency of crime occurrence. The relationship between the number of frequency of crime occurrence and frequency of actual crime occurrence was analyzed by correlation coefficient.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.85-88
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• 2002

We have implemented a system of falling weight impact tester. Absorbed energy of orthotropic composites with using T300 fiber, which are composed of the same fiber and stacking number is higher than that of quasi-isotropic specimen over impact energy 7J, but in case of using T700 fiber, much difference does not show. Also, absorbed energy of orthotropic composites with using T300 fiber, which are composed of stacking number and orientation became more than that of T700 fiber specimen; however great change doesn't show in case of quasi-isotropic specimens. Delamination area of impacted specimens was measured with ultrasonic C-scanner to find correlation between impact energy and delamination area. Delamination area and frequency responses was evaluated between impacted and unimpacted specimens. There is a strong correlation between frequency responses and impact-induced delamination. The presence and scale of damages have been investigated based on the variations of frequency responses.

• Korean Journal of Human Ecology
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• v.13 no.6
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• pp.833-845
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• 2004

This study examines different individual and environmental factors that affect children's self-control. For an analysis, locus of control, perceived competence, and achievement motivation were all included in individual variables. For family variables, mothers' parenting and patents' marriage conflict were examined. For classroom psycho-social environment, teacher support, peer relationship, class involvement, and teachers' supervision were used. The sample consisted of 548 fifth and sixth grade children. Statistics and methods used for the data analysis were Cronbach's alpha, frequency, percentage, Pearson's correlation, and Hierarchical Regression. Several major results were found from the analysis: First, locus of control, perceived competence, and achievement motivation had a positive correlation with children's self-control. Second, mothers' affective parenting had a positive correlation with children's self-control. However, mothers' controlling parenting and parents' marriage conflict had a negative correlation with it. Third, teacher support, peer relationship, and class involvement had a positive correlation with children's self-control. In addition, teacher supervision had a positive correlation with girls' self-control. Fourth, class involvement, locus of control, and academic competence were important variables predicting boys' self-control. On the other hand, Class involvement, achievement motivation, academic competence, teacher's supervision, and mothers' controlling parenting were important variables predicting girl's self-control.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.207-210
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• 2003

In this research analyzed the daily precipitation depths of 4 climatic stations in south eastern part of Korea. It aimed to present some indices for regionalization of the area. The items are frequency distributions of precipitation quantity and days and the longest days less than class limit set up by arithmetic differences. The regression analysis between class value and frequency show very good correlation coefficients better than 0.99 which are cubic equation for the precipitation, exponential equation for the precipitation days, and first degree equation for the longest day less than class limit.

• Nutrition Research and Practice
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• v.2 no.4
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• pp.275-282
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• 2008

In this study, the soy food intake behaviors including perception and intake frequency of soybean foods by sociodemographic variables were analyzed in housewives. The perception of housewives for soy foods showed that soybean paste, soybean curd, and Dambuk were high in the descending order for nutritional quality and health promotion effect, and soybean paste received the highest score in taste and flavor. Soybean sprouts received the highest evaluation score in the economic aspect. In the aspect of safe food, soybean paste received the highest evaluation score, as mush as a traditional food. The analysis of perception by sociodemographic variables showed that soybean curd, Dambuk, and soybean sprouts had higher perceptions as education level increased, and soy milk had higher perceptions in subjects with younger age and with employment. In the intake frequency, more than 50% of the subjects had soybean curd, soybean sprouts, and soybean paste more than once a week. The analysis for correlation between the intake frequency of soy foods and the degree of perception showed that taste and flavor had high correlation with the intake frequency of soy foods except soybean sprouts. The intake frequency of soybean paste, Dambuk, and soy milk had positive correlations to familiarity and that of soy milk had positive correlations to nutrition and health perception, and those of soybeam paste, soybean sprouts, and soy milk had positive correlations to safe food perception. From the above results, housewives in Korea had very high perceptions to nutritional quality and health promotion effect of soy foods and the degree of perception and accompanied intake frequency had significant differences by age, education level, and economic level among sociodemographic variables.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.1
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• pp.30-35
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• 2017

In this study, we measured the natural frequencies of aluminum honeycomb sandwich beams using digital image correlation technique. The vibration images were captured using two high speed digital cameras and the images were converted to displacements by the digital image correlation technique. Displacement data in time domain were tranformed to frequency domain data by fast Fourier transform software. To reduce noise invoked by random exitation, a spectrum averaging technique and Savitsky-Golay digital filter were adopted. A conventional vibration measurement using an accelerometer and a finite element analysis were performed to compare the results by high speed digital camera measurement method. In conclusion, new method using high speed digital cameras and digital image correlation technique can measure the vibration of beam structures and can be applied to bio-structures where sensors cannot be attached.