• 한국경영과학회지
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• 제28권4호
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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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• 제35권1호
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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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• 제26권3호
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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.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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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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• 제31권4호
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• pp.855-870
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• 2011

본 논문에서는 한국 베이비붐 세대의 미래 사건에 대한 주관적 기대가 자산축적에 미친 효과를 분위회귀분석(quantile regression)을 통해 살펴보았다. 한국고령화패널 1, 2차년도(2006, 2008년) 자료를 이용하여 자산 결정요인을 추정한 결과, 학력, 성별, 자녀수는 어떤 분위에서도 유의한 결정요인이었다. 특히, 학력과 자녀수는 상위 분위로 갈수록 총자산의 격차를 확대시키는 방향으로 증가하였다. 미래 사건에 대한 주관적 기대의 경우, 증여에 대한 기대가 높을수록, 좀 더 긴 수명을 기대할수록, 베이비붐 세대는 좀 더 많은 자산축적을 하고 있는 것으로 추정되었다. 한편 노후 생활에 대한 국가의 보장 정도가 개인의 자산축적을 구축하는 정도는 총자산 하위 분위 보다는 상위 분위에서 증가하였으며, 상위 분위의 효과는 통계적으로도 유의하였다.

• 사회복지연구
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• 제47권3호
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• pp.35-60
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• 2016

본 연구는 보육을 둘러싼 갈등이 계속적으로 심화되는 한국사회에서 공보육서비스, 부모휴가급여, 양육수당 등 대표적인 가족정책을 통한 급여가 가구소득, 엄마의 노동시장에서의 지위 등 계층에 따라 불평등하게 분배되고 있는 양상을 분위회귀분석(quantile analysis)을 통해 실증적으로 분석하였다. 분석의 결과는 다음과 같다. 첫째, 보육서비스와 휴가급여 측면에서 모두 가구소득과 여성의 노동시장에서의 지위에 따라 이용률에서의 차이가 발견되었다. 둘째, 가족정책을 통한 지원금의 수준이 가구소득 4분위, 어머니가 상용직인 집단에서 가장 높게 나타났다. 셋째, 다중회귀분석 결과, 1분위를 기준으로 4분위, 맞벌이가구, 어머니가 상용직인 경우, 그리고 미취학 자녀수가 많고 부모 학력이 높을수록 가족정책을 통한 지원금의 수준이 증가하였다. 마지막으로 분위회귀분석을 통해 가족정책 지원금 불평등의 영향요인을 분석한 결과, 전업모를 기준으로 상용직이라는 엄마의 안정적인 근로형태가 가족정책 급여의 차이와 불평등을 심화시키는 대표적인 요인으로 나타났다. 이러한 분석 결과를 토대로 본 연구에서는 한국의 가족정책이 가진 보편성과 재분배 속성이 구현되기 위한 방안으로서 근로형태에 관계없이 정책 접근 권리에 대한 평등한 보장, 이전소득을 통한 저소득가구에 대하여 최저소득 보장, 정책의 보편적 적용의 보장 등을 제안하였다.

• 보건행정학회지
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• 제25권3호
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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.

• 한국산림과학회지
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• 제94권2호통권159호
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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.

• 유통과학연구
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• 제15권9호
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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.

• 토지주택연구
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• 제11권1호
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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.