• 응용통계연구
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• 제31권2호
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• pp.287-301
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• 2018

0이 과도하게 많이 나타나는 자료는 여러 다양한 분야에서 흔히 볼 수 있다. 이러한 자료들을 분석할 때 대표적으로 영과잉 포아송 모형이 사용된다. 특히 반응변수들 사이에 상관관계가 존재할 때에는 랜덤효과를 영과잉 포아송 모형에 도입해서 분석해야 한다. 이러한 모형은 주로 빈도론자들의 접근방법으로 분석되어왔는데, 최근에는 베이지안 기법을 사용한 분석도 다양하게 발전되어 왔다. 본 논문에서는 반응변수들 사이에 상관관계가 존재하는 경우 랜덤효과가 포함된 영과잉 포아송 회귀모형을 베이지안 추론 방법을 토대로 제안하였다. 이 모형의 적합성을 판단하기 위해 모의 실험을 통해 랜덤효과를 고려하지 않은 모형과 비교 분석하였다. 또한, 실제 지역사회 건강조사 흡연 자료에 직접 응용하여 그 결과를 살펴보았다.

• 응용통계연구
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• 제27권5호
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• pp.743-753
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• 2014

Kim 등 (2006)과 Kim 등 (2009)은 2002년에 (사)볼런티어 21에서 조사한 설문자료에 기초하여 우리나라 개인의 기부횟수에 영향을 주는 유의적 설명변수를 보고한 바 있다. 본고에서는 Kim 등 (2006)과 Kim 등 (2009)의 계산오류를 발견하여 이를 수정하고, 아울러 Kim 등 (2009)이 적용한 0이 팽창된 포아송 모형에 로지스틱 회귀모형을 추가하였다. 동 로지스틱 모형으로 기부행위(0, 1)에 영향을 주는 설명변수를 식별하고, 아울러 기부횟수가 작은 군(群)과 큰 군(群)을 판별하여 주는 설명변수를 식별하고자 한다.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 학술논문집
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• pp.292-303
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• 2004

기존의 지수실험장치에 PLC와 스텝핑 모터로 구성된 자동화 제어장치를 부착하여 중성자 선원과 검출기를 자동으로 정확하게 이동할 수 있도록 개선하였다. 또한 GENIE 2000 라이브러리에 기반을 둔 MCA와 PLC를 동시에 구동할 수 있는 통합자동화 프로그램을 개발하였다. 이와 같이 체계적인 장치로 개선된 실험장치를 사용하여 고리 1 호기의 사용후핵연료 집합체, Cl4, Jl4 및 G23과 고리 2 호기의 사용후핵연료 집하체, J44의 대한 지수실험을 수행하였다. 그 결과 4 개 집합체에 대한 평균 지수감쇠계수는 각각 0.1302, 0.1267, 0.1247 및 0.1210으로 결정되었다.

• Environmental Engineering Research
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• 제21권4호
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• pp.365-372
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• 2016

The effects of hydrodynamics and alum dose on particle growth were investigated by monitoring particle counts in a rapid mixing process. Experiments were performed to measure the particle growth and breakup under various conditions. The rapid mixing scheme consisted of the following operating parameters: Velocity gradient (G) ($200-300s^{-1}$), alum dose (10-50 mg/L) and mixing time (30-180 s). The Poisson regression model was applied to assess the effects of the doses and velocity gradient with mixing time. The mechanism for the growth and breakup of particles was elucidated. An increase in alum dose was found to accelerate the particle count reduction. The particle count at a G value of $200s^{-1}$ decreased more rapidly than those at $300s^{-1}$. The growth and breakup of larger particles were more clearly observed at higher alum doses. Variations of particles due to aggregation and breakup of micro-flocs in rapid mixing step were interactively affected by G, mixing time and alum dose. Micro-flocculation played an important role in a rapid mixing process.

• Human Ecology Research
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• 제59권4호
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• pp.489-500
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• 2021

The purpose of this study was to identify the impact of pornography use among adolescents on their subsequent violent sexual behavior, and to ascertain the moderating effect of family support. The study was conducted with a sample of 2,087 Korean middle and high-school students. To analyze the data, a descriptive analysis, a correlation analysis, and a Poisson regression were conducted using SPSS 24.0. A Poisson regression was performed because the dependent variable, violent sexual behavior, was measured by the frequency of occurrence, and most responses were distributed at '0', indicating a non-normal distribution. The results indicated that 8.1% of adolescents admitted to having sexually violent experiences over the past year, with a relatively high rate of sexual harassment. Secondly, 53.3% of adolescents had used pornography over the past couple of years, with the highest percentage of use occurring via the Internet. Finally, pornography use among adolescents had a significant and direct impact on their sexually violent behavior, with family support playing a moderating role. This indicated that, for adolescents with a high level of family support, the impact of pornography usage on sexually violent behavior decreased. Based on these results, we discuss practical and policy interventions to prevent sexually violent behavior by adolescents.

• Journal of Preventive Medicine and Public Health
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• 제55권4호
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• pp.371-378
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• 2022

Objectives: No studies have examined the association between preterm birth rates and socioeconomic factors in Japan using nationwide statistical data. We analyzed the association between preterm birth rates and household occupation using Vital Statistics data. Methods: Aggregated Vital Statistics data from Japan from 2007 to 2019 were obtained from the Ministry of Health, Labour and Welfare. From the data, the number of births according to year, age group, gestational period, number of pregnancies, and household occupation were used in this study. Crude preterm birth rates and preterm birth rates adjusted by maternal age according to household occupation were calculated for each year. Poisson regression analysis was conducted to evaluate the association between household occupation and preterm births. Results: Unemployed households had the highest preterm birth rate, and households with an occupation classification of "full-time worker 2" (an employee at a large company, civil servant, or board member) had the lowest preterm birth rate throughout each period. Poisson regression analysis revealed that unemployed households were statistically significantly associated with a high preterm birth risk. In contrast, the preterm birth rate adjusted by maternal age remained stable throughout each period regardless of household occupation, and preterm birth rates were found not to have increased in recent years in Japan. Conclusions: Unemployed households had higher preterm birth rates than other household occupations. Further studies investigating the characteristics of unemployed households are needed to identify the reasons for this disparity.

• 한국병원경영학회지
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• 제28권3호
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• pp.39-46
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• 2023

Purpose: Korean medical services are not balanced across regions and social classes. To prevent mortality gaps, Korea must distribute its medical resources more efficiently. Patient factors affecting emergency room visits serve as basic data for determining best practices for public healthcare distribution. Methods: The data included 18 473 visits by 14 949 de-identified patients who visited a public emergency room over one year. The dependent variable was the number of emergency room visits. A Poisson regression was conducted with the independent variables, comprising sociodemographic, socioeconomic, and spatial accessibility factors and patient characteristics. Results: Older men with higher Korean Triage and Acuity Scale scores visited more frequently. Greater patient-hospital distance decreased visits; however, the presence of a hospital within 1 km of a patient's residence did not affect the number of visits. The use of 119 services was negatively correlated with the number of visits. Visits increased with more medical benefits. Conclusions: Patient age, distance to hospital, use of 119 services, and medical benefits should be considered when planning or managing public hospitals in Korea.

• 한국도로학회논문집
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• 제14권5호
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• pp.133-143
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• 2012

PURPOSES: Using the collected data for crash, traffic volume, and design elements on ramps between 2007 and 2009, this research effort was initiated to develop traffic crash prediction models for expressway ramps. METHODS: Three negative binomial regression models and three zero-inflated negative binomial regression models were developed for individual ramp types, including direct, semi-direct and loop, respectively. For validating the developed models, authors compared the estimated crash frequencies with actual crash frequencies of twelve randomly selected interchanges, the ramps of which have not been used for model developing. RESULTS: The results show that the negative binomial regression models for direct, semi-direct and loop ramps showed 60.3%, 63.8% and 48.7% error rates on average whereas the zero-inflated negative binomial regression models showed 82.1%, 120.4% and 57.3%, respectively. CONCLUSIONS: Conclusively, the negative binomial regression models worked better in traffic crash prediction than the zero-inflated negative binomial regression models for estimating the frequency of traffic accidents on expressway ramps.

• Journal of Ecology and Environment
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• 제35권3호
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• pp.189-194
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• 2012

Coarse woody debris (CWD) is generally considered dead woody material in various stages of forest decomposition and has been hypothesized to be an important habitat feature for mammals in forests of the Pacific Northwest, USA. Sherman and pitfall trapping were conducted for 2 years on three paired sites with low and high amounts of CWD. Deer mice was the dominant species with a total capture of 605 (45.6%). Four species of insectivores were captured, including Sorex moncicolus, S. trowbridgii, S. vagrans, and Neurotrichus gibbsii. A Poisson regression model was used to test whether 11 CWD variables could predict insectivore captures. The volume of logs and mean decay were important variables for deer mice use of CWD. Mean distance from pieces of CWD to the capture point was significantly related to the total number of captures of trowbridge shrew (Sorex trowbridgii) and all insectivore species. Vagrant shrews (Sorex vagrans) were significantly associated with log volume. Retaining large size CWD should be part of a management plan for ground-dwelling insectivores in forests to secure their biodiversity.

• Journal of Korea Trade
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• 제23권2호
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• pp.76-87
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• 2019

Purpose - This study empirically analyzes the effects of the European Union-South Korea Free Trade Agreement on Korean exports in major sectors. Design/Methodology - This study is based on the augmented gravity model with a panel data set covering 51 countries between the years 2000 and 2015. Findings - Main findings of the present study is that the agreement has affected the chemical sector the most. Fixed effects estimation predicted a positive trade effect of 38.3%, while Poisson maximum likelihood estimation predicted an impact of 4.75% in the chemical export sector. Regression results for the other sectors only show insignificant effects. Originality/value - The findings imply that the effects of the EU-South Korea free trade agreement on the Korean exports are quite specific compared to the European ones, meaning that the Korean government should focus on sector-specific programs to maximize the welfare benefits of the free trade agreement.