• Title/Summary/Keyword: 10분위

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Analysis of Long-term Linear Trends of the Sea Surface Height Along the Korean Coast based on Quantile Regression (분위회귀를 이용한 한반도 연안 해면 고도의 장주기 선형 추세 분석)

  • LIM, BYEONG-JUN;CHANG, YOU-SOON
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.23 no.2
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    • pp.63-75
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    • 2018
  • This study analyzed the long-term linear trends of the sea surface height around the Korea marginal seas for the period of 1993~2016 by using quantile regression. We found significant difference about 2~3 mm/year for the linear trend between OLS (ordinary least square) and median (50%) quantile regression especially in the Yellow Sea, which is affected by extreme events. Each area shows different trend for each quantile (lower (1%), median (50%) and upper (99%)). Most areas of the Yellow Sea show increasing trend in both low and upper quantile, but significant "upward divergence tendency". This implies that significant increasing trend of upper quantile is higher than that of lower quantile in this area. Meanwhile, South Sea of Korea generally shows "upward convergence tendency" representing that increasing trend of upper quantile is lower than that of lower quantile. This study also confirmed that these tendencies can be eliminated by removing major tidal components from the harmonic analysis. Therefore, it is assumed that the regional characteristics are related to the long term change of tide amplitude.

A Study of Disease Prevalence According to Green Tea Consumption (녹차 섭취기간에 따른 질병 발현 연구)

  • 백송남;진현화;이현정;김양하;양정례
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.31 no.5
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    • pp.856-861
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    • 2002
  • It has been reported in animal and human studies that green tea shows a health protective characteristics. In the present study, we investigated the disease prevalence according to chronic green tea consumption in 92 subjects (mean age: 59.548.9, men: 41, women: 51) living in green tea cultivation village. The consumption of green tea and other life-style characteristics were ascertained by a questionnaire. The subjects were divided into three groups according to the period of green tea consumption (0, < 10 year, and $\geq$ 10 year). For green tea consumption groups, most of the subjects have been drinking green tea in order to protect disease and recognized the effects of green tea as detoxification of alcohol and smoking, protection of cold or release from fatigue. There were no significant differences in drinking and smoking, physical activity, and a cold prevalence among the groups. Green tea consumption was associated with lower levels of prevalence of tooth decay as well as the osteoporosis. The score of dietary habits was higher by increasing green tea consumption period (p<0.05). Consequently, chronic green tea consumption can be considerably effective in health promotion.

Relationship between the Sample Quantiles and Sample Quantile Ranks (표본분위수와 표본분위의 관계)

  • Ahn, Sung-Jin
    • Communications for Statistical Applications and Methods
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    • v.18 no.6
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    • pp.707-716
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    • 2011
  • Quantiles and quantile ranks(or plotting positions) are widely used in academia and industry. Sample quantile methods and sample quantile methods implemented in some major statistical software are at least seven, respectively. Small looking differences between the methods can make big differences in outcomes that result from decisions based on them. We discussed the characteristics and differences of the basic plotting position using the empirical cumulative probability and the six plotting positions derived from the suggestion of Blom (1958). After discussing the characteristics and differences of seven quantile methods used in the some major statistical software, we suggested a general expression covering all seven quantile methods. Using the insight obtained from the general expression, we proposed four propositions that make it possible to find the plotting position method that correspond to each of the seven quantile methods. These correspondences may help us to understand and apply quantile methodology.

도협소식

  • Korean Library Association
    • KLA journal
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    • v.10 no.7
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    • pp.28-32
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    • 1969
  • PDF

A Study on the User Satisfaction of Demand Response Transport(DRT) by Quantile Regression Analysis (분위회귀분석에 의한 수요응답형교통 이용자 만족도 분석)

  • Jang, Tae Youn;Han, Woo Jin;Kim, Jeong Ho
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.15 no.3
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    • pp.118-128
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    • 2016
  • As the rural areas have experienced the population reduction and the aging, the service level of public transit decreases. This study analyzes the effecting factor to user satisfaction of demand response transport(DRT) as alternative to rural public transit by the quantile regression that aims at estimating either the conditional median or other quantiles of the response variable. Jeonbuk Province tested DRT operations in Dongsang of Wanju County and Sannae of Jeongup City each in 2015. The user DRT satisfaction of Wanju was higher than one of Jeongup in basic statistics analysis. The difference in satisfaction between higher quantile and lower quntile of Wanju is smaller than one of Jeongupy as a result of quantile regression analysis. Also, Wanju DRT continues the second test operation of DRT as satisfaction from Ordinary Least Squares(OLS) close to higher satisfaction quantile.

Influence Comparison of Customer Satisfaction Factor using Quantile Regression Model (분위회귀모형을 이용한 고객만족도 요인의 영향력 비교)

  • Kim, Seong-Yoon;Kim, Yong-Tae;Lee, Sang-Jun
    • Journal of Digital Convergence
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    • v.13 no.6
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    • pp.125-132
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    • 2015
  • It is current situation that a number of issues are being raised how the weight is calculated from customer satisfaction survey. This study investigated how the weight of satisfaction for each quantile is different by comparing ordinary least square regression model to quantile regression model and carried out bootstrap verification to find the influence difference of regression coefficient for each quantile. As the analysis result of using R(Quantreg package) that is open software, it appeared that there was the influence size of satisfaction factor along study result and quantile and there was the significant difference statistically regarding regression coefficient for each quantile. So, to use quantile regression model that offers the influence of satisfaction factor for each customer group along satisfaction level would contribute to plan the quantitative convergence policy for customer satisfaction.

Family Gaps Across the Wages Distribution in Korea (자녀유무별 여성임금격차(Family gap) : 소득분위에 따른 비교연구)

  • Huh, Soo-Yeon
    • Korean Journal of Social Welfare Studies
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    • v.43 no.2
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    • pp.345-366
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    • 2012
  • This study analyze Family gaps(the wage gap between mothers and non-mothers) across the wages distribution in Korea using 2008 Korean Labor and Income Panel Study. Analysis models include Heckman's two stage estimation to control women's labor participation selection and Quantile regression method to examine the effects of children at different points of the wage distribution. The result indicates that first, comparing non-mothers, mothers with one child suffer statistically significant hourly wage losses at 25th, 50th, and 75th distribution, however not significant effects are found at lowest(10th) and highest(90th) distribution. Second, comparing non-mothers, mothers with two more children suffer statistically significant hourly wage losses at all distribution. Family gap differs across the wage distribution and highest family gaps are found at 25th distribution. With these results, the author suggests universal family policies to support mothers' labor participation and the reconciliation of work and family.

Intergenerational economic mobility in Korea using a quantile regression analysis (한국의 세대 간 경제적 이동성 - 분위수회귀분석을 중심으로 -)

  • Richey, Jeremiah;Jeong, Kiho
    • Journal of the Korean Data and Information Science Society
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    • v.25 no.4
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    • pp.715-725
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    • 2014
  • This study uses a quantile regression analysis to investigate intergenerational economic mobility in Korea. The analysis is based on data from the 1st through 11th waves of the Korean Labor and Income Panel Study (KLIPS) conducted from 1998-2008. The household nature of the data allows us to link parents' incomes to children's incomes at different points in time. Using a quantile regression analysis instead of mean one reveals that the effect of fathers' earnings are different across the conditional distribution of sons' earnings, particularly being larger on the upper quantile than on the lower quantile. After controlling effect of sons' college education by including a dummy variable for the degree, however, the pattern among quantile effects for fathers' earnings is no longer clear. Instead a new pattern emerges that education has a much larger effect on the upper quantiles than on the lower ones. Using nonparametric estimates of conditional density curves based on the quantile regression results, we derive some interesting features in graphical forms, which are not obvious in numerical analysis.

An Analysis of Eating Out Expenditure Behavior of Urban Households by Decile Group (도시가계의 10분위별 외식비 지출행태 분석)

  • Choi, Mun-Yong;Mo, Soo-Won;Lee, Kwang-Bae
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.11
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    • pp.7820-7830
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    • 2015
  • Korean households' demand for food consumed away from home is on the steady increase. The ratio of eating-out expenditure of the household income, however, tends to decrease recently irrespective of income groups. This paper, therefore, aims to analyse the food-away-from-home expenditures of salary and wage earners' households by income decile group. The eating-out expenditure is modelled as a function of household income and then estimated using econometric methods such as regression, rolling regression, impulse response, and variance decomposition of forecast error. The regression results indicate that the higher the income decile group is, the lower the income elasticity of eating-out expenditure is, and the high income groups enjoy seasonal eating-out, the low groups do not. The coefficients of dynamic rolling regression are much smaller than those of static one, meaning that households tend to decrease the eating-out expenditure of their income. The impulse response analysis suggests that the eating-out expenditure increase of higher income groups lasts long relative to that of lower income groups. The variance decomposition, also, shows that household income plays much more important role in determining eating-out expenditure at the higher income groups than at the lower income groups.

Infinite Slope Stability Analysis based on Rainfall Pattern in Ulleung-do (울릉도지역 강우패턴을 고려한 무한사면 안정성 해석)

  • Lee, Chung-Ki;Moon, Seong-Woo;Yun, Hyun-Seok;Seo, Yong-Seok
    • The Journal of Engineering Geology
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    • v.28 no.1
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    • pp.11-24
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    • 2018
  • The purpose of slope stability analysis is to predict the location and occurrence time considering the rainfall, topographic and soil characteristics, etc. In this study, infinite slope stability analysis considering the time distribution characteristics of the daily maximum rainfall was conducted using a model that combines a digital terrain model and a groundwater flow model. As the results of slope stability analysis, 69.1~70.0% of Fs < 1 cells are in the range of slope angle $20{\sim}50^{\circ}$ and Fs < 1 starts to appear in 2 hours for $Q_1$ model, 5 hours for $Q_2$, 7 hours for $Q_3$ and 6 hours for $Q_4$. Furthermore, the maximum number of Fs < 1 cells appear in 6 hours for $Q_1$ model, 12 hours for $Q_2$, 16 hours for $Q_3$ and 20 hours for $Q_4$, and the area of Fs < 1 is 14.3% for $Q_1$ model, 15.0% for $Q_2$, 15.6% for $Q_3$, and 16.3% for $Q_4$.