• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.4
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• pp.145-153
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• 2003

In this Paper, we examine the limiting distributional behaviour of extreme values of mixed Erlang random variables. We show that, in the finite mixture of Erlang distributions, the component distribution with an asymptotically dominant tail has a critical effect on the asymptotic extreme behavior of the mixture distribution and it converges to the Gumbel extreme-value distribution. Normalizing constants are also established. We apply this result to characterize the asymptotic distribution of maxima of sojourn times in M/M/s queuing system. We also show that Erlang mixtures with continuous mixing may converge to the Gumbel or Type II extreme-value distribution depending on their mixing distributions, considering two special cases of uniform mixing and exponential mixing.

• Journal of the Korean Statistical Society
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• v.35 no.1
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• pp.37-47
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• 2006

Recently, as a result of the growing interest in modeling stationary processes with discrete marginal distributions, several models for integer valued time series have been proposed in the literature. One of these models is the integer-valued autoregressive (INAR) models. However, when modeling with integer-valued autoregressive processes, the distributional properties of forecasts have been not yet discovered due to the difficulty in handling the Steutal Van Ham thinning operator 'o' (Steutal and van Ham, 1979). In this study, we derive the mean squared error of h-step-ahead prediction from a Poisson INAR(1) process, reflecting the effect of the variability of parameter estimates in the prediction mean squared error.

• Journal of Forest and Environmental Science
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• v.26 no.3
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• pp.193-202
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• 2010

To analyze the effects of tree roots on the stability of damage slope, distributional and physical properties of five-year Pinus densiflora roots were investigated. In the composition of roots, the proportion of main root to lateral root was 1 to 9 in slope condition. Root tensile force was increased in accordance with increased proportion to diameter of Pinus densiflora roots. However, tensile strength was decreased in proportion to diameter of roots. Root shear strength showed that soil containing Pinus densiflora roots was higher than that of non-treated soils. This result shows that Pinus densiflora roots significantly stabilize the surface-soil rather than sub-soil in damage slopes.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.525-530
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• 2007

Although just developed in recent years, curved box girder has widely used in modern highway system due to their load resistance capacity as well as aesthetic considerations. According to recent literature reviews on curved box girder designs, distortional load was not considered as much as it deserves to be. In practice, the effect of distributional force is very small in straight bridge systems but yet unknown how it is in curved bridge systems. For the reason, this paper will show up an extensive parametric study on distortional behavior of curved box girder with trapezoidal section. Based on Dabrowski formulas, using finite element method, various bridges were investigated. In this study, following parameters will be included: span length, curvature radius, section height, section width, and internal section angle (web slope). From the obtained results, some initial geometric parameters are proposed for curved box girder bridges.

• 한국노년학
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• v.31 no.4
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• pp.855-870
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• 2011

This paper investigates the effect of retirement-related subjective expectations on the capital accumulation of the Korean baby-boom generation. Using the 1st, 2nd waves of the KLoSA (2006, 2008), we estimate the distributional effects with quantile regression. In addition, the endogeneity of the expectation variables is handled using the fixed effect model. The quantile regression results reveal that the schooling, gender and the number of children are important determinants, but their effects are heterogenous across quantiles to a significant margin. The expectations of the stronger bequest motives and longer lifespan turned out to lead to more capital accumulation. The expectation regarding the expanded role of government retirement support seemed to crowd out private savings for the baby boomers with the total assets over 0.7 percentile.

• Korean Journal of Social Welfare Studies
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• v.47 no.3
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• pp.35-60
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• 2016

This study analyzes the unequal distributional effect of threesome of family policy(child benefit, childcare services and parental leave) focusing on family income, mother's status in labor market in Korea. To measure the unequal distributional effect of family policies, this study used the quantile analysis. The results of this study are as follows. First, in terms of childcare service and parental leave, there is some difference of the rate of use by family income and mother's status in labor market. Second, total public fund for childcare services, child benefits and parental leave are high in fourth income quintile, and mothers work regularly. Third, public fund is high in fourth income quintile, dual earners, mothers work regularly, the family has many number of child, and is high educational level of parents. Finally, the results of quantile regression show the biggest factors of unequal distribution of family policy are mother's stable work and it deepens the inequalities and differences. Based on these results, this article suggests that more equal right to access and use family policy regardless of the type of employment, adequate minimum income through income transfer, and universal application of the policy.

• Health Policy and Management
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• v.25 no.3
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• pp.240-251
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• 2015

Background: Dentist's income is quite variable. We investigate the factors underlying the distribution of dental revenue and dentist income. Methods: Financial and structural variables of private dental practices(N=13,967) were examined with 2010 Economic Census microdata which include non-insurance revenue. We conducted quantile regression method(QRM) and ordinary least square(OLS) in treating skewness and heteroskedasticity of distributions. The effective estimation for the upper and lower range of distribution becomes possible by QRM. Results: Mid-career dentists are shown to have higher revenue and income. Male dentists achieve the higher revenue and income than female dentists in all quantiles. Group practices show lower income per owner than solo practices significantly. The revenue and income are increased with increasing size of clinics. The high cost in renting the clinic office is found to have a big positive effect on the revenue but a little positive effect on the income. Interestingly the density of dentists shows negative effect on the lowest quantile of the revenue but positive effect on the highest quantile. The lowest quantile of the revenue in the capital areas have the relatively high revenue. The lowest quantile of the income in metropolitan city show higher income than those in other areas significantly. Conclusion: The suggested QRM is shown to have more effective and efficient tool in finding out determinants of dentists' revenue and income of our concern. The results of this study are expected to be employed for dentists preparing for the opening practices in their organizational settings and locational selections. The distributional efficiency of dental human resources could be accomplished if policy makers guide dentists with this knowledge.

• Journal of Korean Society of Forest Science
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• v.94 no.2 s.159
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• pp.108-111
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• 2005

This study was conducted to identify the road effect on small rodent populations within fragmented forest areas around the road from June to September 2002, in 9 study sites of Baekdugdaegan mountains, Korea. Two species of small rodents, Korean field mouse Apodemus peninsulae and striped field mouse Apodemus agrarius, were captured in this study. Korean field mouse preferred forest area, and striped field mouse generally has been found edge area around road. Mean body weight of Korean field mouse was significantly different, but that of striped field mouse was not between both distance from road. Korean field mouse is forest-dwelling species and their distribution is limited in forest area. In contrast, striped field mouse has wide distributional range around road. The effects of road is different in each small rodent species and their habitat preferences.

• Journal of Distribution Science
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• v.15 no.9
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• pp.85-93
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• 2017

Purpose - The volume and valence of online word-of-mouth(eWOM) have become an important part of the retailer's market success for a wide range of products. This study aims to investigate how the growth of eWOM has generated the product's final financial outcomes in the introductory period influences. Research design, data, and methodology - This study uses weekly box office performance for 117 movies released in the South Korea from July 2015 to June 2016 using Korean Film Council(KOFIC) database. 292,371 posted online review messages were collected from NAVER movie review bulletin board. Using regression analysis, we test whether eWOM incurred during the opening week is valuable to explain the last of box office performance. Three major eWOM metrics were considered after controlling for the major distributional factors. Results - Results support that major eWOM variables play a significant role in box-office outcome prediction. Especially, the growth rate of the positive eWOM volume has a significant effect on the growth potential in sales. Conclusions - The findings highlight that the speed of eWOM growth has an informational value to understand the market reaction to a new product beyond valence and volume. Movie distributors need to take positive online eWOM growth into account to make optimal screen allocation decisions after release.

• Land and Housing Review
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• v.11 no.1
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• pp.79-86
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• 2020

The number of business closure is one of key indicators diagnosing the status of local economy. The increases in closure are attributed to various endogenous/exogenous factors such as decreases in sales of stores, decline of local market, deterioration of global financial condition, but it is not trivial task to figure out the cause and effect mechanism among variables. The effects of those factors are expected to show geographical variations, which the empirical analysis results in this study presented. As such, the objective of this study is to estimate the effects of variables on increase in the number of business closure and examine the distributional properties of the geographic variations of the effects among spatial units of analysis. To this end, GWR (Geographically Weighted Regression) model was utilized to draw empirical analysis outcomes. It is expected that the outcomes of the sort in this research may be useful in aiding decision-making process of drafting locality-specific policies and/or deciding where to prioritize the limited public resources available.