• Proceedings of the IEEK Conference
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• 2000.11c
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• pp.69-72
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• 2000

In this paper, a novel algorithm for digital watermarking is proposed. We use two pattern keys from BCH (15, 7) code and one randomizing key. In the embedding process, optimal watermark coefficients are determined by statistical analysis of the DCT coefficients from the standpoint of HVS. In the detection, watermark coefficients are restored by correlation matching of the possible pattern keys and minimizing the estimation errors. Attacks tested in the experiments ate image enhancement and image compression (JPEG). Performance is evaluated by BER of the logo images and SNR/PSNR of the restored images. Our method has higher performance against JPEG attacks. Analysis for the performance is included.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2001.11a
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• pp.15-20
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• 2001

This study investigated the condensation heat transfer coefficients of R-22, R-290 and R-600a inside horizontal tube. Heat transfer measurements were peformed for smooth tube with outside diameter of 12.7 mm Condensation temperatures and mass velocity were ranged from 308 K to 323 K and $51kg/\textrm{m}^2s$s to $250kg/\textrm{m}^2s$, respectively. The test results showed that the local condensation heat transfer coefficients increased as the mass flux increased, and also the effects of mass velocity on heat transfer coefficients of R-290 and R-600a were less than R-22. Average condensation heat transfer coefficients of natural refrigerants were superior to that of R-22. The present results had a good agreement with Haraguchi's correlation.

• Journal of Korean Academy of Nursing
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• v.45 no.2
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• pp.240-250
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• 2015

Purpose: The purpose of this study was to validate the Korean version of the Ethical Leadership at Work questionnaire (K-ELW) that measures RNs' perceived ethical leadership of their nurse managers. Methods: The strong validation process suggested by Benson (1998), including translation and cultural adaptation stage, structural stage, and external stage, was used. Participants were 241 RNs who reported their perceived ethical leadership using both the pre-version of K-ELW and a previously known Ethical Leadership Scale, and interactional justice of their managers, as well as their own demographics, organizational commitment and organizational citizenship behavior. Data analyses included descriptive statistics, Pearson correlation coefficients, reliability coefficients, exploratory factor analysis, and confirmatory factor analysis. SPSS 19.0 and Amos 18.0 versions were used. Results: A modified K-ELW was developed from construct validity evidence and included 31 items in 7 domains: People orientation, task responsibility fairness, relationship fairness, power sharing, concern for sustainability, ethical guidance, and integrity. Convergent validity, discriminant validity, and concurrent validity were supported according to the correlation coefficients of the 7 domains with other measures. Conclusion: The results of this study provide preliminary evidence that the modified K-ELW can be adopted in Korean nursing organizations, and reliable and valid ethical leadership scores can be expected.

• Speech Sciences
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• v.9 no.3
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• pp.3-16
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• 2002

We examined some problems in speaker identification procedures: transformation of acoustic parameters into auditory scales, invalid measurement values, and comparability of spectral energy values across the frequency range. To resolve those problems, we analyzed the acoustic spectral energy of three Korean numbers produced by ten female students from narrow-band spectrograms at 19 proportional time points of each voiced segment. Then, cells of the first five spectral matrices were averaged to form a matrix model for each speaker. The correlation coefficients and sum of the absolute amplitude difference in each pair of the spectral models of the ten subjects were obtained. Also, some individual matrix models were compared to those of the same subject or the other subject with a similar spectral model. Results showed that in numbers '2' and '9' subjects could not be clearly distinguished from the others but in number '4' it shed some possibility of setting threshold values for speaker identification if we employed the coefficients and the sum of absolute difference. Further studies would be desirable on various combinations of the range of long-term average spectra and the degree of signal pre-emphasis.

• Journal of Environmental Science International
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• v.14 no.12
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• pp.1171-1176
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• 2005

This study was conducted to identify the runoff characteristics of non-point source according to rainfall in Dalseo and Daemyung watershed. Land-uses of the Dalseo and Daemyung watershed were surveyed to urban $72.1\%$ and mountainous $6.7\%$, and urban $49.3\%$ and mountainous $20.5\%$, respectively Mean runoff coefficients in each area were estimated to Dalseo watershed 0.49 and Daemyung watershed 0.16. In the relationship between the rainfall and peak-flow correlation coefficients(r) were determined to Dalseo watershed 0.9060 and Daemyung watershed 0.5620. In the relationship between the antecedent dry period and flrst flow runoff correlation coefficients(r) were determined to Dalseo watershed 0.7217 and Daemyung watershed 0.2464. In the relationship between the rainfall and watershed loading, exponent values of SS in Dalseo and Daemyung watershed were estimated to 0.54 and 0.496, respectively.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.1
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• pp.54-61
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• 2001

Condensing heat transfer coefficients of R-22 and R-134a were measured in smooth, horizontal copper tubes with inner diameters of 1.77mm, 3.36mm, and 5.35mm, respectively. The experiments were conducted in the closed loop, which was driven by a magnetic gear pump. Data are presented for the following range of variables : mass velocity from 200 to 500kg/$m^2$.s and quality from 0 to 1.0. The heat transfer coefficients in the small diameter tubes (ID < 7mm) were observed to be strongly affected by various diameters and the heat transfer characteristics in the small diameter tubes differed from those in the large diameter tubes. Heat transfer coefficients in the small diameter tubes are higher than those in the large diameter tubes at the same experimental condition. It was found that some well-known previous correlations(Shahs correlation and Cavallini-Zecchins correlation) were not suitable for small diameter tubes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5A
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• pp.709-716
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• 2000

We present an efficient algorithm using region-based average of variations of local correlation coefficients (LCC) for the extraction of texture regions. The key idea of this algorithm for the classification of texture and shade regions is to utilize the fact that the averages of the variations of LCCs according to different orientations texture regions are clearly larger than those in shade regions. In order to evaluate the performance of the proposed algorithm, we use nine test images (Lena, Bsail, Camera Man, Face, Woman, Elaine, Jet, Tree, and Tank) of 8-bit 256$\times$256 pixels. Experimental results show that the proposed feature extracts well the regions which appear visually as texture regions.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.256-261
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• 2005

In the present experimental study, condensation heat transfer coefficients between R404A and R152a flow in a horizontal smooth tube were compared. The outer and inner diameters of the tube were 9.52 mm and 7.55 mm, respectively, and the heated length was 1045 mm. The mass flux ranged from 150 to 400 $kg/m^{2}s$ and the test section were uniformly heated from 8 to 12. $kW/m^2$. The quality range was from 0.2 to 0.8 at the saturation temperature from 27.3 to $34^{\circ}C$. Experimental condensation heat transfer coefficients increased as the quality and mass flux increased. Modified Dobson and Chato correlation reduced the mean deviation of 5.1% for R404A and 9.4% for R152a than the original correlation$^{(2)}$.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.1
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• pp.29-38
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• 2004

The Condensation heat transfer coefficients of R-22 and R-l34a were measured in smooth horizontal copper tubes with inner diameters of 1.77. 3.36 and 5.35 mm. respectively. The experiments were conducted in a closed loop. which was driven by a magnetic gear pump. They were Performed for the following ranges of variables: mass flux (200 to $500\;kg/\textrm{m}^2{\cdot}s$) saturation temperature $30^{\circ}C$ and quality (0 to 1.0). The main results obtained are as follows Condensation heat transfer coefficients in the small diameter tubes (ID < 7 mm) were observed to be strongly affected by inner diameter change and to differ from those in the large diameter tubes. The heat transfer coefficients in the small diameter tubes were 20 ~ 40 % higher than those in the large diameter tubes as the inner diameter of the tube was reduced. Also. it was very difficult to apply some well-known previous predictions (Cavallini-Zecchin's. Haraguchi's and Dobson's correlation) to small diameter tubes. Based on an analogy between heat and mass transfer the new correlation is Proposed to predict the experimental data more accurately.

• Bulletin of the Korean Chemical Society
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• v.12 no.3
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• pp.309-315
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• 1991

The thermal transport coefficients-the self-diffusion coefficient, shear viscosity, and thermal conductivity-of liquid argon at 94.4 K and 1 atm are calculated by non-equilibrium molecular dynamics (NEMD) simulations of a Lennard-Jones potential and compared with those obtained from Green-Kubo relations using equilibrium molecular dynamics (EMD) simulations and with experimental data. The time-correlation functions-the velocity, pressure, and heat flux auto-correlation functions-of liquid argon obtained from the EMD simulations show well-behaved smooth curves which are not oscillating and decaying fast around 1.5 ps. The calculated self-diffusion coefficient from our NEMD simulation is found to be approximately 40% higher than the experimental result. The Lagrange extrapolated shear viscosity is in good agreement with the experimental result and the asymptotic formula of the calculated shear viscosities seems to be an exponential form rather than the square-root form predicted by other NEMD studies of shear viscosity. The agreement for thermal conductivity between the simulation results (NEMD and EMD) and the experimental result is within statistical error. In conclusion, through our NEMD and EMD simulations, the overall agreement is quite good, which means that the Green-Kubo relations and the NEMD algorithms of thermal transport coefficients for simple liquids are valid.