• Molecular & Cellular Toxicology
• /
• v.3 no.2
• /
• pp.145-149
• /
• 2007

Studies of relationship between structure and toxicity of azo dyes have been performed with comparative molecular field analysis (CoMFA) techniques. 3D QSTR analyses indicate that the steric and electrostatic interactions are important. The steric field based model gives strong correlation ($q^2$=0.57, $r^2$= 0.92). The steric field in conjunction with electrostatic field give more strong correlation ($q^2$=0.57, $r^2$=0.95). All study indicates that a bulky and electronegative group at benzene ring and a small group at position 3 of aniline ring might be significant to reduce the mutagenicity.

• Advances in Traditional Medicine
• /
• v.8 no.1
• /
• pp.32-38
• /
• 2008

Galgeuntang water extract exhibited a strong free radical scavenging activity and reducing power determination. However, a gradual increase in the free radical scavenging activity and reducing power determination was obtained with increasing concentrations. The highest radical scavenging activity was shown by the water extract from Galgeuntang (116.93 ${\mu}g$/mL) and the water extract from Cinnamonum cassia Presl. (95.01 ${\mu}g$/mL). These results of phenolic and flavonoid contents of the extracts indicated that the strong radical scavenging activity of the Cinnamonum cassia Presl. extract might be in part due to the phenolic compounds. The correlation coefficient between TPC and DPPH ($r^2$ = 0.9312), TFC and DPPH ($r^2$ = 0.9677), showed positive correlation among total phenolic/flavonoid contents and antioxidant activity. These results suggest that Galgeuntang has a potential antioxidant activity.

• Nuclear Engineering and Technology
• /
• v.37 no.3
• /
• pp.293-298
• /
• 2005

We have performed the density functional theory calculations of $UO_2$ using the spin-polarized generalized gradient approximation (SP-GGA) and the SP-GGA+U approach. The SP-GGA+U approach correctly predicts the insulating electronic structure with antiferromagnetic ordering, but the SP-GGA calculations predict metallic behavior. The cohesive properties obtained from the SP-GGA+U calculations are in good agreement with the available experimental results and previous calculations. The spin-polarized local density of states shows that the antiferromagnetic ordering of $UO_2$ is governed by 5f orbitals of uranium ion. Our calculations demonstrate that the strong correlation of U 5f electrons should be taken into account for a reliable description of $UO_2$ physics.

• East Asian Economic Review
• /
• v.19 no.2
• /
• pp.189-220
• /
• 2015

Multi-scale representations are effective in characterising the time-frequency characteristics of financial return series. They have the capability to reveal the properties not evident with typical time domain analysis. Given the aforesaid, this study derives crucial insights from multi scale analysis to investigate the co-movements between Indian and emerging Asian equity markets using wavelet correlation and wavelet coherence measures. It is reported that the Indian equity market is strongly integrated with Asian equity markets at lower frequency scales and relatively less blended at higher frequencies. On the other hand the results from cross correlations suggest that the lead-lag relationship becomes substantial as we turn to lower frequency scales and finally, wavelet coherence demonstrates that this correlation eventually grows strong in the interim of the crises period at lower frequency scales. Overall the findings are relevant and have strong policy and practical implications.

• Journal for History of Mathematics
• /
• v.19 no.4
• /
• pp.97-106
• /
• 2006

The lattice originated from logic, not mathematics. Around 1880, Peirce thought that all the lattices were distributives, however $Schr{\"{o}}der$ corrected the error around 1890. In 1993, Birkhoff used the term lattice for the first time that had a different meaning from today's lattice. This paper introduces Peirce, and studies correlation among atomic lattices, atomistic lattices, J-lattices, strong lattices and distributive lattices.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.6
• /
• pp.1845-1847
• /
• 2013

The lateral photovoltaic effect (LPE) can be observed in semiconductors by irradiating a light spot position between electrodes on sample's surface. Because lateral photovoltaic voltage (LPV) is sensitively changed by light spot position, a LPE device has been tried as a position-sensitive detector. This study discusses the correlation between LPV and conductivity in p-type silicon and nano-structured Au deposited p-type silicon (nano-Au silicon), respectively. Conductivity measurement of the sample was carried out using the four-wire method to eliminate contact resistance, and conductivity dependence on LPV was simultaneously measured by changing the light irradiation position. The result showed a strong correlation between conductivity and LPV in the p-type silicon sample. The correlation coefficient was 0.87. The correlation coefficient between LPV and conductivity for the nano-Au silicon sample was 0.41.

• Communications for Statistical Applications and Methods
• /
• v.21 no.5
• /
• pp.445-459
• /
• 2014

This paper investigates the dependence structure of Korean financial markets (stock, foreign exchange (FX) rates and bond) using copula-GARCH and dynamic conditional correlation (DCC) models. We examine GJR-GARCH with skewed elliptical distributions and four copulas (Gaussian, Student's t, Clayton and Gumbel) to model dependence among returns, and then employ DCC model to describe system-wide correlation dynamics. We analyze the daily returns of KOSPI, FX (WON/USD) and KRX bond index (Gross Price Index) from $2^{nd}$ May 2006 to $30^{th}$ June 2014 with 2,063 observations. Empirical result shows that there is significant asymmetry and fat-tail of individual return, and strong tail-dependence among returns, especially between KOSPI and FX returns, during the 2008 Global Financial Crisis period. Focused only on recent 30 months, we find that the correlation between stock and bond markets shows dramatic increase, and system-wide correlation wanders around zero, which possibly indicates market tranquility from a systemic perspective.

• Speech Sciences
• /
• v.10 no.3
• /
• pp.29-36
• /
• 2003

The purposes of this study was to conduct a correlational analysis among $F_^{0}$, Jitter, Shimmer, and NHR (HNR), and NNE estimated by three speech analysis softwares, MDVP, Praat and Dr. Speech. Thirty females and 15 males with normal voice participated in the study. We used Sound Forge 6.0 to record their voice. MDVP, Praat and Dr. Speech were used to measure the acoustic parameters. The Pearson correlation coefficient was determined through a statistical analysis. The results came out as follows: Firstly, there was a strong correlation between $F_^{0}$ and Shimmer of both instruments. However, there was no correlation between Jitter of both instruments. Secondly, Shimmer showed a stronger correlation with HNR, NHR, and NNE than Jitter. Therefore, Shimmer was considered to be more useful and sensitive parameter to identify dysphonic voice compared to jitter.

• KCID journal
• /
• v.18 no.1
• /
• pp.25-32
• /
• 2011

In order to effectively manage the reservoir, reservoir water quality management should be based on physicochemical and configurational characteristics. In this research, correlation between factors affecting the reservoir water quality was examined. Chl-a and COD shows the highest positive correlation. Chl-a and T-P also has a high positive correlation, however Chl-a and T-N show lower correlation relatively. Even though T-N is an important factor for phytoplankton growth which increase Chl-a concentration, corelation of Ch1-a and T-N shows that enough nitrogen in the reservoir isn't no longer limiting factor. The age of reservoir can cause of increasing COD and SS. Embankment height and elevation of reservoirs shows strong negative correlation to water quality. That means reservoir which is higher embankment height and locate in higher elevations is less contaminated. Regression expression was derived with Chl-a and water quality parameters, and height of reservoir. Finally Chl-a was simulated using regression expression and it was a good approach to predict the Chl-a concentration.

• Journal of Korean Society for Quality Management
• /
• v.46 no.3
• /
• pp.509-522
• /
• 2018

Purpose: The purpose of this study was to propose more accurate mathematical model which can represent result of government quality assurance activity, especially corrective action and flaw. Methods: The collected data during government quality assurance activity was represented through histogram. To find out which distributions (Poisson distribution, Zero-Inflated Poisson distribution) could represent the histogram better, this study applied Pearson's correlation coefficient. Results: The result of this study is as follows; Histogram of corrective action during past 3 years and Zero-Inflated Poisson distribution had strong relationship that their correlation coefficients was over 0.94. Flaw data could not re-parameterize to Zero-Inflated Poisson distribution because its frequency of flaw occurrence was too small. However, histogram of flaw data during past 3 years and Poisson distribution showed strong relationship that their correlation coefficients was 0.99. Conclusion: Zero-Inflated Poisson distribution represented better than Poisson distribution to demonstrate corrective action histogram. However, in the case of flaw data histogram, Poisson distribution was more accurate than Zero-Inflated Poisson distribution.