• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.179-182
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• 2011

Second-order rate constants ($k_{OH^-}$) have been measured spectrophotometrically for reactions of Y-substituted phenyl phenyl thionocarbonates (4a-i) with $OH^-$ in 80 mol % $H_2O$/20 mol % DMSO at $25.0{\pm}0.1^{\circ}C$. The $k_{OH^-}$ values for the reactions of 4a-i have been compared with those reported previously for the corresponding reactions of Y-substituted phenyl phenyl carbonates (3a-i) to investigate the effect of changing the electrophilic center from C=O to C=S on reactivity and mechanism. Thionocarbonates 4a-i are less reactive than the corresponding carbonates 3a-i although 4a-i are expected to be more reactive than 3a-i. The Bronsted-type plot for reactions of 4a-i is linear with $\beta_{lg}$ = -0.33, a typical $\beta_{lg}$ value for reactions reported to proceed through a stepwise mechanism with formation of an intermediate being the rate-determining step (RDS). Furthermore, the Hammett plot correlated with $\sigma^o$ constants results in much better linearity than that correlated with $\sigma^-$ constants, indicating that expulsion of the leaving group is not advanced in the RDS. Thus, alkaline hydrolysis of 4a-i has been concluded to proceed through a stepwise mechanism with formation of an intermediate being RDS, which is in contrast to the forced concerted mechanism reported for the corresponding reactions of 3a-i. Enhanced stability of the intermediate upon modification of the electrophilic center from C=O to C=S has been concluded to be responsible for the contrasting mechanisms.

• Mass Spectrometry Letters
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• v.9 no.1
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• pp.30-36
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• 2018

A quantitation method for free amino acids in human serum was developed using a stepwise-dilution method and a bimodal cation exchange (CEX)/hydrophilic interaction liquid chromatography (HILIC)-tandem mass spectrometry system equipped with an electrospray ionization source (ESI/MS/MS). This method, which was validated using quality control samples, was optimized for enhanced selectivity and sensitivity. Dithiothreitol (DTT) was used as a reducing agent to prevent the oxidation of a serum sample ($50{\mu}L$), which was then subjected to stepwise dilution using 3, 30, and 90 volumes of acetonitrile containing 0.1% formic acid. Chromatographic separation was performed on an Imtakt Intrada Amino Acid column ($50mm{\times}3mm$, $3{\mu}m$) in mixed mode packed with CEX and HILIC ligands embedded in the stationary phase. Underivatized free amino acids were eluted and separated within 10 min. As a result of the validation, the precision and accuracy for the inter- and intraday assays were determined as 2.11-11.51% and 92.82-109.40%, respectively. The lowest limit of quantification (LLOQ) was $0.5-4.0{\mu}g/mL$ and the matrix effect was 80.22-115.93%. The proposed method was successfully applied to the quantitative analysis of free amino acids in human serum.

• The Journal of the Korea Contents Association
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• v.15 no.1
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• pp.211-220
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• 2015

Purpose: The purpose of this study was to identify the effect of self efficacy and self leadership on stress in adolescents. Methods: Data were collected from 722 adolescents and analyzed using descriptive statistics, t-test, ANOVA, Scheffe's test, Pearson correlation coefficients and stepwise multiple regression with the SPSS 20.0 program. Results: Stress differed according to gender, grade, economic level. Self efficacy and self leadership had a significant negative correlation with stress. Stepwise multiple regression analysis showed self efficacy(general self efficacy), self leadership(cognitive strategies), gender(female), grade(high school) explained 32.5% of the total variance in stress. The findings indicate that self efficacy and self leadership had an influence on stress. Conclusions: The results of this study offer basic data for the development of intervention programs to prevent adolescents stress.

• Korean Journal of Hospice Care
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• v.6 no.2
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• pp.69-78
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• 2006

Purpose: This study was conducted to analysis relationship about quality of life and family burden of the home-based hospice patient families. Method: The subjects consisted of 94 families with home-based hospice patient. The ages of the subjects were 17-73 years with hospice patient who receivedhome visiting care and registered at 4 hospitals in Daegu and Kyung-Buk. The data was collected from March to November 2004. The instruments used for the study were Quality of Life Scale (GLS) and Family Burden Questionnaire (FBQ). The analysis was done using frequency, mean, standard deviation, correlation and stepwise multiple regression with SPSS WIN 11.0. Results: The results were as follows: 1. The mean score of family burden was 3.36 ($\pm0.55$). The highest mean score of family burden 6 factors were wellness of future 3.85($\pm1.10$), and the second was economic family burden 3.63($\pm0.97$). 2. The mean score of quality of life was 3.09 ($\pm0.48$). The lowest score of quality of life 6 factors were economic status 2.86($\pm0.54$), and the second was physical state and function 3.01($\pm0.62$). 3. In the home-based hospice patient families, family burden had significant negative correlation with quality of life(r=-0.25, p=0.012). 4. Emotional status accounted for 11% of family burden in the home-based hospice patient families by means of stepwise multiple regression. 5. Economical status accounted for 18 and age accounted for an additional 11% of quality of life in the home-based hospice patient families by means of stepwise multiple regression. Conclusion: The finding showed that family burden and quality of life of home-based hospice patient families were significantly negative correlation and the highest factor of family burden was wellness of future and the most important factor of quality of life was economic status.

• Journal of Digital Convergence
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• v.17 no.1
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• pp.259-267
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• 2019

The purpose of this study was to examine relationships among empowerment, awareness and performance on standard precautions and identify the factors that affect performance of standard precaution in nursing students experiencing clinical practice. The data were collected from 168 nursing students who experienced clinical practice in the two colleges located Jeonnam. The data were analyzed by descriptive statistics, t-test, ANOVA, Scheffe, Pearson's correlation coefficient, and stepwise multiple regression with SPSS 20.0 program. The result of the stepwise multiple regression indicates the awareness predict 77.7% (F=579.84, p<.001) in the performance of standard precaution. Therefore, it is necessary to develop awareness of the standard precaution strategy program for improving the performance of standard precautions in nursing students experiencing clinical practice.

• Journal of Korean Society of Forest Science
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• v.82 no.4
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• pp.420-430
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• 1993

This study was conducted to investigate the effect of the forest environmental factors(5 items) and physico-chemical properties of soil(13 items) on the growth of Pinus thunbergii stands. The 218 plots were sampled over the coastal district of the whole country. In statistical analysis, the explanatory variables were soil and environmental factors(18 items), and the response variable was the site index of Pinus thunbergii stands. Data computation was processed in order of preparation of original data, computation of inner correlation matrix table by correlation analysis, calculation of partial correlation coefficients and coefficients of determination, estimation of regression equation by stepwise begression analysis, and stepwise regression analysis by factor score of factor analysis. The main results obtained were summarized as follows ; 1. The site index in Pinus thunbergii stands way highly correlated with effective soil depth(r=0.8668), slope percentage, organic matter, and total nitrogen. 2. According to the coefficients by partial correlation analysis, effective soil depth(r=0.6270), slope percentage (r=-0.5423) and base saturation(r=0.3278) among environmental factors had a great effect on tree growth. 3. With stepwise regression analysis, the factors effecting on the Pinus thunbergii stands growth were effective soil depth, slope percentage, organic matter, base saturation, soil pH, content of silt, exchangeable Ca, and etc. 4. Estimation equation for the site index of Pinus thunbergii stands was given by $Y=13.2691+0.0242\;X_2-1.2244\;X_4+0.6142\;X_5-0.3472\;X_{11}+0.0355\;X_{13}+0.1552\;X_{15}-0.1002\;X_{17}$. The coefficient of determination for the estimation model was 0.77, which was significant at the 1 percent level. 5. In result of factor analysis by the environmental factors, principal components were 6 factors, and communality contribution percentage was 71.1 percent. 6. By stepwise regression analysis between factor score and site index of Pinus thunbergii stands, the factor group effecting on site index was 5 principal components. The coefficients of determination was 85 percent, which was significant at the 1 percent level. In conclusion, on the occasion of analizing which factors to effect on the tree height growth in Pinus thunbergii stands the stepwise regression analysis proved to be greatly significant. Also the management of Pinus thunbergii stands should be working by the above selected growth factors.

• Journal of Broadcast Engineering
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• v.21 no.3
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• pp.425-435
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• 2016

In this paper, we propose a classification model by analyzing raw material images recorded using a color CCD camera to automatically classify good and defective agricultural products such as rice, coffee, and green tea, and raw materials. The current classifying agricultural products mainly depends on visual selection by skilled laborers. However, classification ability may drop owing to repeated labor for a long period of time. To resolve the problems of existing human dependant commercial products, we propose a vision based automatic raw material classification combining mean shift clustering and stepwise region merging algorithm. In this paper, the image is divided into N cluster regions by applying the mean-shift clustering algorithm to the foreground map image. Second, the representative regions among the N cluster regions are selected and stepwise region-merging method is applied to integrate similar cluster regions by comparing both color and positional proximity to neighboring regions. The merged raw material objects thereby are expressed in a 2D color distribution of RG, GB, and BR. Third, a threshold is used to detect good and defective products based on color distribution ellipse for merged material objects. From the results of carrying out an experiment with diverse raw material images using the proposed method, less artificial manipulation by the user is required compared to existing clustering and commercial methods, and classification accuracy on raw materials is improved.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.1
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• pp.138-143
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• 2011

In spite of abundant clinical resources of stroke patients, the objective and logical data analyses or diagnostic systems were not established in oriental medicine. As a part of researches for standardization and objectification of differentiation of syndromes for stroke, in this present study, we tried to develop the statistical diagnostic tool discriminating the 4 subtypes of syndrome differentiation using the essential indices considering the sex. Discriminant analysis was carried out using clinical data collected from 1,448 stroke patients who was identically diagnosed for the syndrome differentiation subtypes diagnosed by two clinical experts with more than 3 year experiences. Empirical discriminant model(V) for different sex was constructed using 61 significant symptoms and sign indices selected by stepwise selection. We comparison. We make comparison a between discriminant model(V) and discriminant model(IV) using 33 significant symptoms and sign indices selected by stepwise selection. Development of statistical diagnostic tool discriminating 4 subtypes by sex : The discriminant model with the 24 significant indices in women and the 19 significant indices in men was developed for discriminating the 4 subtypes of syndrome differentiation including phlegm-dampness, qi-deficiency, yin-deficiency and fire-heat. Diagnostic accuracy and prediction rate of syndrome differentiation by sex : The overall diagnostic accuracy and prediction rate of 4 syndrome differentiation subtypes using 24 symptom and sign indices was 74.63%(403/540) and 68.46%(89/130) in women, 19 symptom and sign indices was 72.05%(446/619) and 70.44%(112/159) in men. These results are almost same as those of that the overall diagnostic accuracy(73.68%) and prediction rate(70.59%) are analyzed by the discriminant model(IV) using 33 symptom and sign indices selected by stepwise selection. Considering sex, the statistical discriminant model(V) with significant 24 symptom and sign indices in women and 19 symptom and sign indices in men, instead of 33 indices would be used in the field of oriental medicine contributing to the objectification of syndrome differentiation with parsimony rule.

• Food Science of Animal Resources
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• v.31 no.1
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• pp.115-121
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• 2011

The objective of this study was to develop models to predict freshness factors (total viable counts (TVC), pH, volatile basic nitrogen (VBN), trimethylamine (TMA), and thiobarbituric acid (TBA) values) and the storage period in beef using a visible and near-infrared (NIR) spectroscopic technique. A total of 216 beef spectra were collected during the storage period from 0 to 14 d at a $10^{\circ}C$ storage. A spectrophotometer was used to measure reflectance spectra from beef samples, and beef freshness spectra were divided into a calibration set and a validation set. Multi-linear regression (MLR) models using the stepwise method were developed to predict the factors. The MLR results showed that beef freshness had a good correlation between the predicted and measured factors using the selected wavelength. The correlation of determination ($r^2$), standard error of prediction (SEP), and ratio of standard deviation to SEP (RPD) of the prediction set for TVC was 0.74, 0.64, and 2.75 Log CFU/$cm^2$, respectively. The $r^2$, SEP, and RPD values for pH were 0.43, 0.10, and 1.10; those for VBN were 0.73, 1.45, and 2.00 mg%; those for TMA were 0.70, 0.19, and 2.58 mg%; those for TBA values were 0.73, 0.13, and 2.77 mg MA/kg; and those for storage period were 0.77, 1.94, and 2.53 d, respectively. The results indicate that visible and NIR spectroscopy can predict beef freshness during storage.

• Journal of the Korea Society for Simulation
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• v.17 no.4
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• pp.199-208
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• 2008

Lately, since Complementary Metal Oxide Semiconductor(CMOS) image sensor system has low power, low cost and been miniaturized, hardware and applied software studies using these strengths are being carrying on actively. However, the products equipped with CMOS image sensor based polling method yet has several problems in degree of completeness of applied software and firmware, compared with hardware’s. CMOS image sensor system has an ineffective synchronous problem due to superfluous message exchange. Also when a sending of data is delayed continually, overhead of re-sending is large. So because of these, it has a problem in structural stability according to Polling Method. In this study, polling cycle was subdivided in high-speed synchronization method of firmware -based through MCU and synchronization method of Stepwise was proposed. Also, re-connection and data sending were advanced more efficiently by using interrupt way. In conclusion, the proposed method showed more than 20 times better performance in synchronization time and error connection. Also, a board was created by using C328R board of CMOS image sensor-based and ATmega128L which has low power, MCU and camera modules of proposed firmware were compared with provided software and analyzed in synchronization time and error connection.