• Advances in environmental research
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• v.6 no.4
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• pp.265-279
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• 2017

The climate change has made adverse effects on land surface temperature for many regions of the world. Several climatic studies focused on different downscaling techniques for climatological parameters of different regions. For statistical downscaling of any hydrological parameters, conventional Neural Network Models were used in common. However, it seems that in any modeling study, uncertainty is a vital aspect when making any predictions about the performance. In this paper, Gamma Test is performed to determine the data length selection for training to minimize the uncertainty in model development. Another measure to improve the data quality and model development are wavelet transforms. Hence, Gamma Test with Wavelet decomposed Feedforward Neural Network (GT-WNN) model is developed and tested for downscaled land surface temperature of Patna Urban, Bihar. The results of GT-WNN model are compared with GT-FFNN and conventional Feedforward Neural Network (FFNN) model. The effectiveness of the developed models is illustrated by Root Mean Square Error and Coefficient of Correlation. Results showed that GT-WNN outperformed the GT-FFNN and conventional FFNN in downscaling the land surface temperature. The land surface temperature is forecasted for a period of 2015-2044 with GT-WNN model for Patna Urban in Bihar. In addition, the significance of the probable changes in the land surface temperature is also found through Mann-Kendall (M-K) Test for Summer, Winter, Monsoon and Post Monsoon seasons. Results showed an increasing surface temperature trend for summer and winter seasons and no significant trend for monsoon and post monsoon season over the study area for the period between 2015 and 2044. Overall, the M-K test analysis for the annual data shows an increasing trend in the land surface temperature of Patna Urban.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.94-96
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• 2003

Since 1995, MOCT(Ministry of Construction and Transportation) and KOWACO(Korea Water Resources Corporation) have established the National Groundwater Monitoring Network in South Korea and also MOE(Ministry of Environment) has operated Groundwater Quality Monitoring network. Until 2001, 202 monitoring stations by MOCT and 780 monitoring wells by MOE have been constructed, measured groundwater level and analyzed water samples. Groundwater quality analysis has been conducted two times a year during last 6 years for all monitoring wells. The quality data has about 15 components including pH, COD, Count of Coliform group, and etc.. Trend analysis has been peformed for 6 components(Coliform, pH, COD, NO$_3$-N, Cl and EC) of water quality which are analyzed more than 7 times for total monitoring wells. Two test methods have been used ; Sen's test and Mann-Kendall test. These trend tests have been done at the 0.05 significance level. By the result of Sen's test, Count of Coliform group has either upward or downward trends at 4.3 percent of the monitoring points. pH does at 5.6 percent, COD does at 8.6 percent, Nitrate-Nitrogen does at 13.2 percent, Chloride does at 13.4 percent, and. EC does at 11.6 percent of the monitoring points. The exact causes of the groundwater quality trends are difficult to specify. Notable downward trends in nitrate at many monitoring points may be the result of reduction on some contamination sources. Potential causes include diminished agricultural areas, improvements in sewage treatment and a decrease in atmospheric deposition. Increase in chloride at many monitoring points may be the result of increased non-point source pollution such as road salting and runoff from sprawling paved developments and suburbs.

• Journal of the Ergonomics Society of Korea
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• v.29 no.2
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• pp.183-188
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• 2010

The purpose of this study is to investigate the stationarity of the electromyographic signal in various flexion angles, loads, and window sizes, which influence the result of the mean power frequency (MPF) and median frequency (MNF) analysis. Six healthy subjects participated in the experiment. They were tested in the combination of 3-level flexion angles (0 degree, 22.5 degree, 45 degree) and 3-level loads (0Nm, 30Nm, 60Nm). Electromyographic data were collected for 20 seconds during isometric contraction. The stationarity of collected data were analyzed with four different window sizes including 250, 500, 1000 and 2000ms. Two test methods for stationarity such as Reverse Arrangements Test and Modified Reverse Arrangements Test were used. In order to show the effect of nonstationarity, the increasing/decreasing trend of MPF and MNF trend were discussed. In results, the stationarity of the electromyographic signal decreased as flexion angle increased and load decreased while window size decreased based on Reverse Arrangements Test. The highest stationarity was shown at 500 ms window in Modified Reverse Arrangements Test. The inclination of MNF and MPF indicated 3.6-6.3%, 3.8-5.1% discrepancy compared to the result from stationary data.

• The Korean Journal of Applied Statistics
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• v.30 no.4
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• pp.503-512
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• 2017

In test with multiple choices, it is necessary to have the position of correct answers of each question spreaded evenly over all the questions in order to minimize the influence of answering tendency of test takers with preference to specific position of multiple choices. The scores of tests with correct answers in specific positions would not reflect exactly the academic aptitude of examinees who do not know correct answers but have the biased answering tendency. In this paper, we have randomness test for the positioning of correct answers at the 2017 College Scholastic Ability Test (CSAT) using Bartels rank test, the Wald-Wolfowitz runs test, the turning point test, the Cox Stuart trend test, the difference sign test and the Mann-Kendall tank test, etc. We also do independence test between the location of correct answer and the allocation of score in each question, for it may result in overestimating the test-taker with specific position preference in marking correct answers.

• Proceedings of the Korean Society for Quality Management Conference
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• 1998.11a
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• pp.259-268
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• 1998

A family of test statistics is proposed for testing whether or not the mean residual life(MRL) changes its trend. We do not assume that the turning point or the proportion before the turning point is known. This family includes the test statistic proposed by Aly (1990) and Hawkins, Kochar and Leader (1992) for complete samples. We establish the asymptotic null distribution of test statistics and obtain asymptotic critical values of the asymptotic null distribution using Durbin's approximation. We study Monte Carlo simulation to compare the proposed tests with previously known tests.

• Proceedings of the KIEE Conference
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• 2005.07e
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• pp.100-102
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• 2005

This paper is purpose to introduce the database management program of insulation tests for high voltage rotating machines. KEPRI has carried out insulation tests for high voltage equipment since 1998, the number of tests grow larger every year. It is difficult to manage the numerous test results, so we developed the insulation diagnostic database program. The features of this program are an easy-search test result and making a graph of AC, tan${\Delta}$ test. the most useful function is the trend management. Using the trend function, we can find the aging deterioration for high voltage machines easily.

• Nuclear Engineering and Technology
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• v.53 no.11
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• pp.3852-3859
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• 2021

This paper presents experimental and numerical analysis results regarding the effects of an incomplete penetration defect on the fatigue lives of socket welded pipes. For the experiment, four-point bending fatigue tests with various defect geometries (defect depth and circumferential length) were performed, and test results are presented in terms of stress-life data. The results showed that for circumferentially short defects, the fatigue life tends to increase with increasing crack depth, but for longer defects, the trend becomes the opposite. Finite element analysis showed that for short defects, the maximum principal stress decreases with increases in crack depth. For a longer defect, the opposite trend was found. Furthermore, the maximum principal stress tends to increase with an increase in defect length regardless of the defect depth.

• Culinary science and hospitality research
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• v.15 no.3
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• pp.307-323
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• 2009

This study aims to redefine people's attitudes about well-being trend LOHAS(Lifestyles Of Health And Sustainability) by a systematic research on diners' perspectives about LOHAS and menu-selecting behavior since well-being trend has been a main interest of the media and the food service industry. Also, this study has focused on understanding customers' menu-selecting behavior through a customer interest survey and on customers' interests and verifying factors for healthy food inclination and satisfaction level to give basic information and marketing suggestions for healthful menu. SPSS 12.0 was used for the data analysis, and $x^$-test was carried to make clear the different perspectives about well-being trend LOHAS according to the general characteristics of those polled. Factor analysis was done to menu-selecting behavior. Differences between sampling menu-selecting factors and general characteristics(t-test & ANOVA) were inspected and multiple regression analysis between health inclination and satisfaction level was also conducted. According to the survey, customers' well-being menu selecting behavior showed highly in married women, relatively older people, those with higher general income and higher education. Regression analysis showed that menu-selecting behavior influenced customers' inclination toward health and satisfaction level. Therefore, the food service industry should target those groups and improve its promotional communication strategy with proper menu development and an improved concept.

• Journal of the Korea Fashion and Costume Design Association
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• v.6 no.3
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• pp.67-81
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• 2004

This research demonstrates clothing consumption values, fashion preferences of career women from the early 1920s to late 1930s. And having thorough understanding of values and preferences, allows us to establish marketing strategies for clothing companies. The main purpose of this study is (1) to formalize consumer group based upon the clothing consumption values, (2) to find for characteristics of consumer depending on classification of consumption value in clothing, (3) to understand the preferences of career women about fashion trends. Analyzing data was performed 292 copies, resulting factor analysis, Cluster analysis, X-test, Anova, Tukey test, t-test, frequency analysis, and reliability analysis. This paper showed 7 distinctive characteristics of career women about clothing consumption value. These characteristics can be listed as 1) value of brand image, 2) value of self-expression, 3) functional values, 4) epistemic values, 5) coordination values, 6) social values 7) psychological values. Importantly, brand image value became most significant aspects among 7 factors. Analyzing consumers based upon stated 7 factors, it was found that they are segregated into 4 groups; Self-expressive Group, Psychological Stability Group, Functional Group, Social Group. Secondly, for fashion trend preferences, self-expressive group, psychological stability group, and functional group favored Romantic Feminine Style respectively. Social Group showed preference in Nu-Basic'. The reason for such trend dealt with fabric materials and colors. Finally examining population statistics, younger generations showed more preferences in Nu-Basic', and consumers from ages of 26 to 28, 32 to 34 showed preferences in Romantic Feminine' regardless of their household income, clothing related expenditures, jobs, and education level. On the other hand, 'Modem Classic' was popular among college graduates and 'Paradise' was somewhat less popular among all ages except from ages of 32 to 34, consumers consumption 300,000Won to 400,000Won on clothing related expenditures. And 'Energy' seemed to attract more highly educated females, who had more than masters in degrees with over 300,000 to 400,000Won for clothing related expenditures.

• Korean Journal of Ecology and Environment
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• v.50 no.1
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• pp.169-185
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• 2017

Physicochemical properties of water quality were analyzed to understand the long-term variations in Lake Youngrang from 1998 to 2015. Nonparametric statistical methods were applied to deduct correlation among water quality parameters and water quality trend. In total observations(N=64), the Secchi depth (SD) transparency showed significant positive correlation with salinity (r=0.458) and highly significant negative correlation with chlorophyll-a (r= -0.649) for p<0.0001 in two-tailed test of Spearman's rank correlation. Significant negative correlations of SD were observed with chemical oxygen demand (COD), total phosphorus (TP) and total nitrogen (TN). These correlation patterns were very similar in rainy (N=25) and non-rainy (N=39) periods too. Chlorophyll-a (Chl-a) had significant correlation with COD. Sen's slope test was performed along with Mann-Kendall trend test (significance ${\alpha}=0.05$, two-tailed) to find water quality trend. Positive trends were observed for SD and salinity with Sen's slopes 0.012 and 0.385, respectively (p<0.0001). Negative significant trends were observed for total nitrogen (TN) and Chl-a with Sen's slopes -0.02 (p<0.0001) and -0.346 (p=0.0010), respectively. Temperature, COD and phosphorus components had no trends. Carlson's trophic state index (TSI) for SD, TP and Chl-a were obtained in the ranges of 46~80, 37~82 and 39~82, respectively. Trophic index values suggest that Lake Youngrang was mesoeutrophic to eutrophic and there could be possibility of anoxia during the summer and dominance of blue-green algae. Excess nutrient inputs from external and internal sources were the causes of eutrophication in this lake. The findings of this study would be helpful to recognize water quality variables to manage the water body.