• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2887-2890
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• 2003

This paper describes the possibility of analyzing gait pattern from the variation of the lower leg electrical impedance. This impedance is measured by the four-electrode method. Two current electrodes are applied to the thigh, knee, and foot, and two potential electrodes are applied to the lateral, medial, and posterior position of lower leg. The correlation coefficients of the joint angle and the impedance change from human leg movement was obtained using electrogoniometer and 4ch impedance measurement system developed in this study. We found the optimal electrode position for ankle, knee and hipjoint movements based on high correlation coefficient, least interference, and maximum magnitude of impedance change. The correlation coefficients of the ankle, knee, and the hip movements -0.87, 0.957 and 0.80. respectively. From such features of the lower leg impedance, it has been made clear that different movement patterns exhibit different impedance patterns and impedance level. This system showed possibility that lower leg movement could be easily measured by impedance measurement system with a few skin-electrodes.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1998.10a
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• pp.122-125
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• 1998

In this article, a reduction method for nominal variables is presented and its use illustrated. Factor analysis model (FAM) generally enables us to reduce variables having interval or ratio scale based on their correlation coefficients. We developed an extensive method that makes FAM applicative to the case of nominal variables which does not give correlation coefficients, but only the degree of association. Cramer's V coefficient is a well-established measure that provides the strength of association for nominal variables with a range of [0,1]. When Cramer's V coefficient can logically substitute for correlation coefficient, FAM would be extensively used for reduction of nominal variables.

• Geomechanics and Engineering
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• v.15 no.5
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• pp.1091-1100
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• 2018

In this study, the relationships between hydraulic conductivity of GCLs and physico-chemical properties of bentonites were assessed. In addition to four factory manufactured GCLs, six artificially prepared GCLs (AP-GCLs) were tested. AP-GCLs were prepared in the laboratory without bonding or stitching. A total of 20 hydraulic conductivity tests were conducted using flexible wall permeameters ten of which were permeated with distilled deionized water (DIW) and the rest were permeated with tap water (TW). The hydraulic conductivity of GCLs and AP-GCLs were between $5.2{\times}10^{-10}cm/s$ and $3.0{\times}10^{-9}cm/s$. The hydraulic conductivities of all GCLs to DIW were very similar to that of GCLs to TW. Then, simple regression analyses were conducted between hydraulic conductivity and physicochemical properties of bentonite. The best correlation coefficient was achieved when hydraulic conductivity was related with clay content (R=0.85). Liquid limit and plasticity index were other independent variables that have good correlation coefficients with hydraulic conductivity (R~0.80). The correlation coefficient with swell index is less than other parameters, but still fairly good (R~0.70). In contrast, hydraulic conductivity had poor correlation coefficients with specific surface area (SSA), smectite content and cation exchange capacity (CEC) (i.e., R < 0.5). Furthermore, some post-test properties of bentonite such as final height and final water content were correlated with the hydraulic conductivity as well. The hydraulic conductivity of GCLs had fairly good correlation coefficients with either final height or final water content. However, those of AP-GCLs had poor correlations with these variables on account of fiber free characteristics.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.669-672
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• 1998

In this paper, w epropose a fast fractal coding method based on correlation coefficients of subblocks in input image. In the proposed method, domain pool is selected based on correlation analysis of input image and the isometry transform for each block is chosen based on the IFS method. To investigate the performance of the proposed method, we compared image quality and encoding time with full search PIFS method and jacquin's PIFS method. Experimental results show that proposed method yields nearly the same performance in PSNR, and its encoding time is reduced for images size of 512*512 compared with full search PIFS method and jacquin's PIFS method.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.11
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• pp.83-88
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• 2011

The spectral field data on the observation planes inside a mode stirred chamber have been computed by using the FDTD method. They can describe the directional dependence of all supported modes in the reverberation chamber (RC). Correlation coefficients have been found to evaluate the stirring effects. The correlation coefficients were obtained and compared for three different sizes of stirrers and statistical uniformity was investigated.

• Korean Journal of Poultry Science
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• v.50 no.1
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• pp.15-22
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• 2023

This study was to investigate the relationship between chick weight in the growing period and the laying performance of Korean native chicken (KNC) breeders. We measured the body weights of 1,384 KNC breeders at 1-140 days of age at two-week intervals. The age at first egg laying, hen-day and hen-housed egg production, and the egg weights were investigated. Correlation coefficients between the body weight and egg production traits were analyzed. The results showed that the correlation coefficients between body weight and age at first egg laying were significantly positive before 4 weeks, but negative after 8 weeks of age. The correlation coefficients between body weight and egg production rate were estimated to be negative before 8 weeks and positive after 12 weeks of age. Coefficients of hen-day and hen-housed egg production were similar. There was little correlation between body weight and egg weight at 32 weeks of age, whereas a low positive correlation was with egg weight at 50 weeks. In conclusion, there was little correlation between body weight and laying performance before 8 weeks of age, whereas a significant positive correlation was with body weight after 12 weeks. The results suggest that as the chick's weight increases in the late growing stage, sexual maturity is faster, the egg production rate is higher, and the egg weight increases. Therefore, the weight management of KNC female breeders is very important in the late growing stage, and the body weight of chicks must be maintained above the standard weight.

• Microbiology and Biotechnology Letters
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• v.30 no.3
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• pp.282-286
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• 2002

Seasonal succession of algae and water quality parameters were studied in artificial reservoirs in Daegu city from 2000 to 2001. The algal succession was evaluated with respect to dom-inant class and their frequencies. Succession order of algae in two reservoirs was : Bacillariophyceae longrightarrow Chlo-rophyceae longrightarrow Cyanobacteria longrightarrow Bacillariophyceae longrightarrow Bacillariophyceae longrightarrow Cyanobacteria longrightarrow Cyanobacteria longrightarrow Cyanobacteria. This succession order was different from other studies. The local environment condition maybe affects the succession of algae in these reservoirs. As result of correlation analysis between algal biom-ass and water quality parameters, we got low correlation coefficients. Also we got low correlation coefficients between chlorophyll-a and algal biomass. Between chlorophyll-a and water quality parameters, we got high correlation coefficients. An approach having attention to cell biovolume rather than cell number is made to understand the algal community and the ecosystem of reservoir.

• The Journal of the Acoustical Society of Korea
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• v.28 no.2
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• pp.96-106
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• 2009

In this paper, correlation between the headphone's acoustical characteristics and the subjective preferences is analyzed, and a possibility of predicting the subjective preferences using the acoustical characteristics is investigated, The headphone's acoustical characteristics include the total harmonic distortions, the variation of the frequency response which were measured by separate channel and the inter-aural correlation coefficients, Those characteristics were measured in a noise-free anechoic chamber, using a head and torso simulator, The subjective preferences were scored in terms of loudness, clearness, spaciousness, fullness and overall impression, In the subjective listening test, 12 subjects were participated who have plentiful listening experiences, The programs include 5 kinds of musics; korean popular song, pop song, light music, male-voice and classic, The 8 models of the headphones were employed, including 4 closed-type circumaural headphones, 2 open-type supraaural headphones and 2 intra-concha headphones, A significant test was carred on the results from the subjective test, using a two-way ANOVA test, The correlation coefficients between the acoustical parameters and the subjective preferences were computed, Experimental results showed that the variation of the magnitude of frequency response measured from a right channel revealed higher correlation with the subjective preferences. Whereas the inter-aural correlation coefficients have very low correlation coefficients.

• The Journal of the Acoustical Society of Korea
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• v.31 no.2
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• pp.93-99
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• 2012

For speech coding, a vocal tract is modeled using Linear Predictive Coding (LPC) coefficients. The LPC coefficients are typically transformed to Line Spectral Frequency (LSF) parameters which are advantageous for linear interpolation and quantization. If multidimensional LSF data are quantized directly using Vector-Quantization (VQ), high rate-distortion performance can be obtained by fully utilizing intra-frame correlation. In practice, since this direct VQ system cannot be used due to high computational complexity and memory requirement, Split VQ (SVQ) is used where a multidimensional vector is split into multilple sub-vectors for quantization. The LSF parameters also have high inter-frame correlation, and thus Predictive SVQ (PSVQ) is utilized. PSVQ provides better rate-distortion performance than SVQ. In this paper, to implement the optimal predictors in PSVQ for voice storage devices, we propose Multi-Frame AR-model based SVQ (MF-AR-SVQ) that considers the inter-frame correlations with multiple previous frames. Compared with conventional PSVQ, the proposed MF-AR-SVQ provides 1 bit gain in terms of spectral distortion without significant increase in complexity and memory requirement.

• Journal of Animal Science and Technology
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• v.44 no.5
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• pp.523-530
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• 2002

Repeatabilities and Correlations among Average Daily Gain, Backfat Thickness and Lean Percent in Swine The repeatability, correlation and rank correlation coefficients among average daily gain, backfat thickness and lean percent were estimated on the basis of records tested from August 1999 to February 2000 with 695 pigs of Duroc, Landrace and Yorkshire boars and gilts tested at 2nd Korea Swine Test Station located in Ha-dong, Kyeongnam Province. The effect of the sex, breed and month of measured were estimated by the least square method. The repeatabilities were estimated from the component of variance among repeated measurements of the trait for the same animal. The results obtained are summarized as follow ; 1. The means of the major economic traits studied were 142.1 days, 173.7 days and 182.5 days for age at 1st, 2nd and 3rd measure, 57.9%, 56.2% and 55.2% for lean percent at 1st, 2nd and 3rd measure, 1.33cm, 1.61cm and 1.63cm for backfat thickness at 1st, 2nd and 3rd measure, 946.6g, 879.2g and 879.4g for average daily gain at 1st, 2nd and 3rd measure, respectively. 2. The correlation coefficients between the backfat thicknesses measured at 1st and 2nd, at 2nd and 3rd, at 1st and 3rd were 0.424, 0.700 and 1.424, respectively. The correlation coefficients between the lean percent measured at 1st and 2nd, at 2nd and 3rd, at 1st and 3rd were 0.493, 0.619 and 0.471, respectively. The correlation coefficients between the average daily gain measured at 1st and 2nd, at 2nd and 3rd, at 1st and 3rd were 0.716, 0.861 and 0.601, respectively. 3. The rank correlation coefficients between backfat thickness measured at 1st and 2nd, at 2nd and 3rd, at 1st and 3rd were 0.438, 0.693 and 0.441, respectively. The rank correlation coefficients between lean percent measured at 1st and 2nd, at 2nd and 3rd, at 1st and 3rd were 0.508, 0.593 and 0.478, respectively. The rank correlation coefficients between average daily gain measured at 1st and 2nd, at 2nd and 3rd, at 1st and 3rd were 0.704, 0.834 and 0.571, respectively. 4. The estimated repeatabilities of the traits studied were 0.428 for the lean percent, 0.374 for the backfat thickness and 0.673 for the average daily gain, respectively.