• Journal of the Korean Data and Information Science Society
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• 제23권2호
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• pp.385-392
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• 2012

Logistic regression is a well known binary classification method in the field of statistical learning. Mixed-effect regression models are widely used for the analysis of correlated data such as those found in longitudinal studies. We consider kernel extensions with semiparametric fixed effects and parametric random effects for the logistic regression. The estimation is performed through the penalized likelihood method based on kernel trick, and our focus is on the efficient computation and the effective hyperparameter selection. For the selection of optimal hyperparameters, cross-validation techniques are employed. Numerical results are then presented to indicate the performance of the proposed procedure.

• The Journal of Asian Finance, Economics and Business
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• 제7권7호
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• pp.229-239
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• 2020

This article aims to measure the impact of economic growth and urbanization on poverty reduction in Vietnam, and verify whether economic growth and urbanization will help reduce poverty rates. Data for this study are tabular data related to growth, urbanization and poverty at the provincial level for the period of nine years, from 2006 to 2014 provided by the Vietnam General Statistics Office and the Vietnam General Department of Customs. The level of economic growth and urbanization mentioned in the study is reflected in such indicators as GDP value, exports value, imports value, urbanization rate and employment rate. The authors used logistic regression models with fixed-effects and logistic regression models with random effects. With 5% confidence level tested by the Chi-Square test of Hausman trial with the fixed-effect model, research results show that: (1) factors with significant negative impact on the poverty rate include imports value, urbanization rate and, employment rate; (2) factors that do not affect the poverty rate include exports value and GDP value. Based on the research results, this study proposes a number of policy recommendations to help promote economic growth, to sustain the urbanization process, and to contribute directly and positively to poverty reduction in Vietnam.

• 말소리와 음성과학
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• 제16권2호
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• pp.1-9
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• 2024

This study investigates the fixed and random factors affecting response patterns of wh-scope interpretations in Gyeongsang Korean. It employed logistic mixed-effects regression models to analyze responses from 24 participants who listened to 40 pre-recorded stimuli from 40 different speakers. The stimuli consisted of an embedded wh-phrase and an interrogative ending marker, "-nkiko," thereby forming a wh-question, specifically a matrix wh-scope. Participants repeated the test three times. The study found that the prominence level of a prosodic phrase composed of an embedded verb and a complementizer was inversely related to responses with wh-questions, as demonstrated through multiple regression analysis in Yun. The test trial significantly impacted the number of responses with wh-questions, increasing from 50.3% in the first trial to 58.8% and 61.2% in subsequent trials. Examination of random subject effects revealed two main factors influencing responses: morpho-syntactic constraints and prosodic structural integrity. These two factors demonstrated the potential to be inversely weighted. Analysis of random stimulus effects suggested that the prominence level had limited effects on response patterns with each stimulus primarily eliciting one type of responses across trials.

• Child Health Nursing Research
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• 제13권3호
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• pp.318-328
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• 2007

Purpose: Because it is important to prevent adolescents from becoming involved in smoking, this study was done to explore important factors influencing cigarette use and the increase in smoking frequency. Method: For this study the Korea Youth Panel Survey (KYPS) was analyzed. Because the KYPS is longitudinal, a fixed effect regression method was used to control for the effects of time-independent factors. More specifically, a logistic regression was used to explore factors affecting cigarette use, and a Poisson regression was used to explore smoking frequency. Result: As the adolescents got older, the number of male adolescents who tried smoking increased, while the number of female adolescents who tried smoking decreased. Also, the frequency of cigarette use among male and female smokers increased over time. Significant factors affecting cigarette use were friends who smoked, delinquent behavior, and loneliness at schools. Important factors affecting the increase in smoking frequency were grade (e.g., the 2nd- and 3rd-year of middle school), friends who smoked, delinquent behavior, monthly pocket money, expectation for the highest level of education, and attack tendency. Conclusions: To solve the problems linked to adolescent smoking, it is critical to develop intervention programs that target specific homogeneous subgroups of smokers, and that take into consideration gender difference in smoking and factors affecting levels of smoking behavior.

• 노동경제논집
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• 제36권1호
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• pp.63-91
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• 2013

본 연구에서는 경제활동인구 부가조사 자료를 이용하여 비정규직의 세부유형별로 직업훈련의 임금 및 고영안정성 효과를 분석하였다. 성향점수매칭방법을 통하여 선택 편의가 없는 처치효과의 추정치를 구하여 분석한 결과, 정규직의 훈련에 따른 임금효과는 4.2%로 비정규직 가운데 유의하게 나타난 기간제 근로의 2.7%보다 훨씬 높게 나타났다. 통제된 데이터를 기반으로 로지스틱 회귀분석을 이용하여 정규직의 정규직 유지를 분석한 결과, 훈련참여 여부는 통계적으로 유의하지 않았으나 훈련시간은 유의하게 나타났으며, 비정규직의 정규직 전환의 경우에는 기간제 근로에서만 훈련참여 여부 및 훈련시간 모두 유의하게 나타났다. 비정규직 유형 중 기간제가 직업훈련의 임금이나 고용효과 모두에서 긍정적으로 나타난 결과는 정규직과 유사하게 사용자와 피고용인의 관계가 다른 비정규직 유형에 비해 보다 명확하기 때문인 것으로 해석된다.

• 한국임상수의학회지
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• 제40권3호
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• pp.238-241
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• 2023

This study determined the effect of ovarian status at the beginning of the modified Double-Ovsynch program on reproductive performance in dairy cows. In the study, 1,302 cows were treated with a modified Double-Ovsynch program at 56 days after calving. This program comprises administering gonadotropin-releasing hormones (GnRH), prostaglandin F_2α (PGF_2α) 10 days later, GnRH 3 days later, GnRH 7 days later, and GnRH 56 h later, followed by timed artificial insemination (TAI) 16 h later. At the beginning of the program, cows were categorized according to the size of the largest follicle and the presence of a corpus luteum (CL) in the ovaries as follows: 1) small follicle (<5 mm, SF group, n = 100), 2) medium follicle (8-20 mm, MF group, n = 538), and 3) large follicle (≥25 mm, LF group, n = 354) without a CL, or 4) the presence of a CL (CL group, n = 310). The pregnancies per AI after the first TAI were analyzed by logistic regression using the LOGISTIC procedure, and the logistic model included the fixed effects of the herd size, parity, body condition score (BCS) at the first TAI, TAI period, and ovarian status. A larger herd size, higher BCS at the first TAI, and TAI period with no heat stress increased (p < 0.05) the probability of pregnancy per AI after the first TAI. However, ovarian status at the beginning of the program did not affect (p > 0.05) the pregnancies per AI (ranges of 37.9% to 42.9%). These results show that the modified Double-Ovsynch program can be used effectively while maintaining good fertility regardless of the ovarian status in dairy herds.

• 한국노년학
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• 제36권4호
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• pp.1125-1139
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• 2016

본 연구는 은퇴가 중 고령자의 운동과 흡연, 음주행동에 미치는 영향을 검증하고, 은퇴사유에 따라 은퇴가 건강행동에 미치는 영향에 차이가 있는지에 대하여 살펴보았다. 구체적으로 본 연구는 고령화연구패널 조사 1~5차년도(2006~2014) 자료를 활용하여, 패널 고정효과 로지스틱 회귀분석을 실시하였다. 분석 결과, 인구사회학적 특성 및 주관적 건강이 통제된 상태에서도 은퇴는 규칙적 운동수행에 정적인 영향을, 흡연과 음주행동에는 부적인 영향을 미치는 것으로 나타났다. 중 고령자가 은퇴할 경우에 비은퇴자에 비하여 규칙적으로 운동할 가능성이 약간 더 증가하였으며, 흡연할 가능성과 음주를 할 가능성은 모두 감소하였다. 중 고령자가 어떠한 사유로 은퇴하더라도 비은퇴자에 비하여 규칙적으로 운동할 가능성이 높았으나, 흡연 및 음주에 관해서는 은퇴사유에 따라 은퇴의 효과에 차이가 있었다. 즉, 건강상의 이유로 은퇴하거나 정년퇴직한 경우에만 흡연할 가능성이 유의하게 감소하였고, 실직하였거나 여가를 즐기기 위해 은퇴한 경우에는 비은퇴자와 비교하여 흡연여부에 차이가 없었다. 또한 건강상의 이유로 은퇴한 경우에만 음주를 할 가능성이 낮아졌고, 그 외의 사유로 은퇴할 경우에는 비은퇴자에 비하여 음주 여부에 차이가 없었다. 본 연구는 은퇴가 중 고령자의 건강행동에 전반적으로 긍정적인 영향을 미치며, 흡연이나 음주보다도 규칙적 운동의 수행에 가장 긍정적으로 작용함을 밝혔다. 또한 본 연구는 건강상의 이유로 인해 은퇴한 중 고령자는 은퇴를 본인의 건강행동을 개선하는 기회로 적극적으로 활용하는 반면, 실직하였거나 가족원을 돌보기 위하여, 혹은 여가를 즐기기 위해 은퇴한 경우에는 은퇴가 건강행동에 갖는 긍정적 효과가 제한적임을 시사한다.

• 한국학교보건학회지
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• 제21권2호
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• pp.23-33
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• 2008

Purpose: Internet is one of the essential tools in South Korean adolescent life. Recently, researchers suggest that Internet use is positively associated with teens' mental health problems such as depression and suicide. Thus, this study explored a relationship between Internet use and suicide ideation among South Korean adolescents. Methods:　Secondary data, the three-wave Korean Youth Panel Survey, were analyzed. First, in terms of the levels of Internet use and suicidal ideation, t-test was used for examining a gender difference, and Analysis of Variance were used for examining differences across three points in time(waves 2 - 4). Second, logistic analysis was performed to examine the significant association between Internet use and suicide ideation after controlling for the other factors' effects. In this analysis, Fixed Effect Regression Method(FERM) was incorporated as well. FERM was useful in adjusting for the effects of time-invariant factors even without measuring them. As a result, it was possible to obtain more accurate findings. Results: Adolescent depression was an important factor influencing the association between Internet use and suicide ideation. After controlling for the effect of depression, the relationship between Internet use and suicide ideation was no longer statistically significant. Conclusion:　As a proxy to identify teens who are obsessed with suicide ideation, levels of Internet use do not seem useful. Instead, it is necessary to examine teens' access to websites related to suicide.

• Journal of Preventive Medicine and Public Health
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• 제53권6호
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• pp.455-464
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• 2020

Objectives: The distribution of hospitals in Korea is unbalanced in terms of accessibility. Many local public health centers (PHCs) exempt out-of-pocket payments (OOPs) based on local government laws to increase coverage. However, this varies across administrative regions, as many make this exemption for the elderly, while others do not. This study aimed to evaluate the effects of the OOP exemption at local PHCs among elderly individuals. Methods: This study used online data on Korean national law to gather information on individual local governments' regulations regarding OOP exemptions. Individual-level data were gathered from the 2018 Community Health Survey and regional-level data from public online sources. Results: The study analyzed 132 regions and 44 918 elderly people. A statistical analysis of rate differences and 2-level multiple logistic regression were carried out. The rate difference according to whether elderly individuals resided in areas with the OOP exemption was 1.97%p (95% confidence interval [CI], 1.07 to 2.88) for PHC utilization, 1.37%p (95% CI, 0.67 to 2.08) for hypertension treatment, and 2.19%p (95% CI, 0.63 to 3.74) for diabetes treatment. The regression analysis showed that OOP exemption had an effect on hypertension treatment, with a fixed-effect odds ratio of 1.25 (95% CI, 1.05 to 1.48). Conclusions: The OOP exemption at PHCs can affect medical utilization in Korea, especially for hypertension treatment. The OOP exemption should be expanded to improve healthcare utilization in Korea.

• Safety and Health at Work
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• 제13권1호
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• pp.51-58
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• 2022

Introduction: Previous studies on occupational health focussed predominately on the occurrence of occupational diseases. Relatively few studies have measured how employment is associated with the use of healthcare services. This study investigates the association between employment and the extent and range of healthcare use, such as medical expenditures, of women in South Korea. Methods: We analyze data of the Korean Health Panel, an ongoing longitudinal national representative survey, from 2008 to 2017, to identify the status of economic activity of women by year and age group. We estimate the association between female employment status and medical expenditures by using random effect panel Tobit models. Furthermore, we investigate the association between employment status and the range of healthcare services in biomedicine and traditional Korean medicine (KM) by conducting conditional fixed-effects logistic regression analyses. Results: For women aged between 25 and 65 in 2017, the majority of them were employed or self-employed. (The proportion of employment of self-employment equals 64.80%). In addition, working women spent 11.6% less on healthcare than nonworking women, and self-employment lowered the healthcare expenditure by 13.1%. Neither work nor the type of work is related to the types and range of healthcare service use. Being employed or self-employed is negatively associated with women's expenditure on healthcare. Conclusions: The findings show that employment is associated with less spending on healthcare. They imply that employment has a positive impact on women's health.