• Title/Summary/Keyword: size effect model

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Effect of Underground Building for the Groundwater flow in the Ground Excavation (지반굴착에 따른 지반 안정성 평가 시 지하시설물이 지하수흐름에 미치는 영향 분석)

  • Cha, Jang-Hwan;Lee, Jae-Young;Kim, Byung-Chan
    • Journal of Korean Society of Disaster and Security
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    • v.11 no.2
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    • pp.17-28
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    • 2018
  • The purpose of this study is to investigate the effect of underground facilities around excavation zone on groundwater flow characteristics during excavation. The scenarios were constructed considering the size of the underground facility, the separation distance, and the hydraulic gradient. As a result, as the size of the underground facility increases, the difference of head and the hydraulic gradient become large. The shorter the separation distance of underground facility is, the more the difference of head and the hydraulic gradient occur. The effect of hydraulic gradient on model area was relatively small. As a result of analysis of groundwater flow rate for the scenario, groundwater flow rate tends to decrease as the size of underground facility increases or groundwater flow rate tends to decrease as the separation distance decreases. It is necessary to examine the effect of underground facilities on the groundwater flow analysis in the ground excavation.

Evaluation of Changesin the Physical Characteristics of Raindrops Under a Canopy in Central Korea (나무 아래 빗방울(雨滴)의 물리적 특성변화 분석)

  • Kim, Jin Kwan;Kim, Min Seok;Yang, Dong Yoon;Lim, Young Shin
    • Journal of The Geomorphological Association of Korea
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    • v.23 no.3
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    • pp.105-122
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    • 2016
  • To evaluate the changes in the physical characteristics of open rainfall related to canopy effects and rainfall intensity in Korea, the terminal velocity of raindrops and drop size distributions(DSD) were continuously measured by an optical-laser disdrometer in an open site(Op) and in two forest stands(Th1: Larix leptolepis, Th2: Pinus koraiensis) during five rainfall events in 2008. The terminal velocity, DSD and two forms of kinetic energy(KE, $Jm^{-2}$ $mm^{-1}$; KER, $Jm^{-2}$ $h^{-1}$) of open rainfall drops were determined and were compared with those of throughfall drops under two different canopy heights. The effects of the canopy and rainfall intensity, together with wind speed, on the changes in drop size and kinetic energy of throughfall were evaluated. Throughfall drops were larger than open rainfall drops. The distribution of terminal velocities for the drop sizes measured at Th2 was lower than that at Op; however, at Th1 the distribution was similar to that at Op. The total kinetic energy of throughfall at Th1 and Th2 was higher than the total kinetic energy of open rainfall, and the kinetic energy distribution for the drop sizes wassimilar to the drop size distribution. The observed throughfall-KER at Th1 was lower than an estimate previously produced using a model. The overestimation from the modeled value at Th1 was likely to be due to overestimated values of a square root transformation of fall height and its coefficient in the model because the distributions of terminal velocity for the drop size measured at Th1 were similar to those of open rainfall.

Conditions For Hyper-EM And Large Graphical Modelling

  • Kim, Seong-Ho;Kim, Sung-Ho
    • Proceedings of the Korean Statistical Society Conference
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    • 2002.11a
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    • pp.293-298
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    • 2002
  • We propose an improved version of Kim (2000) to the effect that in principle we may deal with a graphical model of any size. Kim (2000) proposed a method of estimating parameters for a model of categorical variables which is too large to handle as a single model. We applied the proposed method to a simulated data of 158 binary variables.

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Small Area Estimation via Nonparametric Mixed Effects Model

  • Jeong, Seok-Oh;Shin, Key-Il
    • The Korean Journal of Applied Statistics
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    • v.25 no.3
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    • pp.457-464
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    • 2012
  • Small area estimation is a statistical inference method to overcome the large variance due to the small sample size allocated in a small area. Recently some nonparametric estimators have been applied to small area estimation. In this study, we suggest a nonparametric mixed effect small area estimator using kernel smoothing and compare the small area estimators using labor statistics.

Fabrication of Aluminium Flake Powder by Ball Milling Process (볼밀링에 의한 알루미늄 프레이크 분말 제조)

  • 이동원
    • Journal of Powder Materials
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    • v.3 no.3
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    • pp.159-166
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    • 1996
  • A series of test were undertaken in order to estabilish the effect of different milling variables on dimension and quality of aluminium flake powder. Milling conditions such as initial powder size, milling container rotation speed, milling time, and ball size were varied to produce aluminium flake powder. Flake powder could then be obtained with size range from 15 $\mu$m to 40 $\mu$m with a maximum specific surface area of 5 $m^{2}$/g by controlling milling conditions. Diameter of milled powders with different milling container rotation speed and ball size were compared with that obtained from theoretical model. The best flake powder was obtained in milling condition of initial powder with average size of 19 $\mu$m, mill container rotation speed of 80 rpm, balls of 9.5 mm diameter, and milling time of 40 hours.

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Decomposing the Effect of Population Changes on Crime Changes

  • Lee, Soochang;Jang, Cheolyeung
    • International Journal of Advanced Culture Technology
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    • v.9 no.1
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    • pp.1-6
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    • 2021
  • This study aims to test the relationship between the change in population size and population composition and crime changes. The analytical model includes variables representing changes in population size and population composition, three dependent variables for crime changes, and three control variables. Changes in popuvpdllation size and population composition are measured by indicators such as population size, gender, age groups, and immigrants and foreign workers, and crime changes by felonious, burglary, and violent crime volumes. The sample includes 154 cities and counties in South Korea, and the sample period is from 2010 to 2017. As a result of the analysis, I examine that the decrease in the number of young and men are likely to lead to a decline in felonious and violent crimes, but a high rate of the elderly and the increasing racial heterogeneity are likely to accelerate the fear and worries about crimes.

Population Aging and Wage Structure: An Empirical Study of Cohort Size Effect on Korean Male Worker since 1990 (인구 고령화와 임금구조: 1990년대 이후 한국 남성 근로자의 세대규모효과에 대한 실증분석)

  • Eom, Dong-Wook
    • Korea journal of population studies
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    • v.31 no.1
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    • pp.75-97
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    • 2008
  • Recently Korea is expected with the decrease of population in working ages and also population structure, especially age structure, has changed as aging goes faster. This study focuses on the relationship between age structure and wage structure to analyzes the cohort size effect on the change of age-earnings profile. Our empirical analysis based on Wright(1991)'s model takes weighted OLS regression using the male worker's data of Ministry of Labor 'Wage Structure Survey'($1990{\sim}2006$). In pooled data, we take the conclusion that the cohort size effect was found in high school and college graduate workers, but the effect is different between them. The labor market entry effect of high school graduate workers is negative(-) and his persistent effect is positive(+). On the other hand, the cohort size effect of college graduate workers have appeared the opposite directions in contrary with the existing results of Welch(1979) and Wright(1991). This results are seen as the possibility that college graduate worker has the benefit of wage level by his relative cohort size in spite of high unemployment of young graduate. It will be the sign of need that we should interest in the change of age structure with balancing the labor supply side approach and the demand side study which the previous studies was mainly tended to focus on.

A Meta-Analysis on the Effect of Entrepreneurship on the Entrepreneurial Intention: Mediating Effect of Entrepreneur Education (기업가정신이 창업의지에 미치는 영향에 관한 메타분석: 창업교육의 매개효과)

  • Yoon, Byeong seon;Kim, Chun Kyu
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.15 no.3
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    • pp.207-221
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    • 2020
  • This study conducted a meta-analysis on the effects of innovation, risk-taking, and enterprising on entrepreneurship. From 2013 to 2020, 392 papers, which were judged as quantitative research from doctoral and master thesis, and academic journals published in Korea were selected as research subjects. 28 duplicates of thesis and thesis are excluded. A total of 52 papers were finally selected, excluding 312 papers that were insufficient to be used as research data because there were no statistical values such as correlation coefficients. For the 52 selected papers, the homogeneity of the variables was first verified. As a result of the homogeneity test, the innovativeness, risk-taking, initiative, and entrepreneurship education all showed great effects on heterogeneity, and the average effect size was analyzed by random effect model. The average effect size analyzed was 0.38 ~ 0.49, and all four variables showed moderate average effect size. As a result of analyzing the average effect size by forest plot, all showed proper results. From the results of funnel plot analysis of entrepreneurship education, published errors were confirmed asymmetric. Research data on entrepreneurship education shows that it cannot represent the whole. It is a structural equation model with entrepreneurship and entrepreneurial intention as a parameter. Iinnovation and risk-taking have an impact on entrepreneurship by taking entrepreneurship education as a parameter. Initiative had an effect on the entrepreneurial intention a business, regardless of entrepreneurship education. In a number of studies, university entrepreneurship education has had an impact on the entrepreneurial intention. It should be changed to entrepreneurship education that combines theory and practice. Entrepreneurship education should be transformed into continuous and field-oriented education.

The Effect of CVD Reaction Variable on SnO2 Powder Characteristics

  • Kim, Kyoo-Ho
    • The Korean Journal of Ceramics
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    • v.4 no.3
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    • pp.235-239
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    • 1998
  • Ultrafine $SnO_2$ powder was prepared by the diffusion mixing gas-phase reaction of $SnCl_4$(g) and water vapor. The effects of reaction variables, such as the chloride partial pressure, the reaction temperature, and the residence time is the reactor, on the powder size were examined systematically. Calculated concentration and distribution of chemical species, using the Burke-Schumann diffusion mixing model, were compared with the experimetal results. The effects of the reaction variables on the powder size were also discussed qualitatively.

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A Study on the Effect of Change Management for the ERP Performance in Small and Medium Companies (변화관리요인이 중소기업의 ERP도입성과에 미치는 영향 연구)

  • Park, Chy-Gwan
    • Journal of Information Technology Applications and Management
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    • v.15 no.4
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    • pp.123-136
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    • 2008
  • This study tried to find out the effect of change management on the ERP performance in small and medium size companies. Communication, BPR management, education and training were selected as independent variables which might bring an effect on ERP performances which were classified as quality and quantity one. Structure equation model was built and analyzed with AMOS 5.0 version from data gathered through 127 companies which already implemented ERP systems. The result of this study shows that all the three independent variables give positive impacts on two dependent variables, which means change management is critical when small and medium size companies want to implement ERP systems.

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