• Journal of Preventive Medicine and Public Health
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• v.46 no.1
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• pp.10-18
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• 2013

Objectives: We investigated the association between particulate matter less than $10{\mu}m$ in aerodynamic diameter ($PM_{10}$) exposure and non-accidental mortality in Asian populations by meta-analysis, using both time-series and case-crossover analysis. Methods: Among the 819 published studies searched from PubMed and EMBASE using key words related to $PM_{10}$ exposure and non-accidental mortality in Asian countries, 8 time-series and 4 case-crossover studies were selected for meta-analysis after exclusion by selection criteria. We obtained the relative risk (RR) and 95% confidence intervals (CI) of non-accidental mortality per $10{\mu}g/m^3$ increase of daily $PM_{10}$ from each study. We used Q statistics to test the heterogeneity of the results among the different studies and evaluated for publication bias using Begg funnel plot and Egger test. Results: Testing for heterogeneity showed significance (p<0.001); thus, we applied a random-effects model. RR (95% CI) per $10{\mu}g/m^3$ increase of daily $PM_{10}$ for both the time-series and case-crossover studies combined, time-series studies relative risk only, and case-crossover studies only, were 1.0047 (1.0033 to 1.0062), 1.0057 (1.0029 to 1.0086), and 1.0027 (1.0010 to 1.0043), respectively. The non-significant Egger test suggested that this analysis was not likely to have a publication bias. Conclusions: We found a significant positive association between $PM_{10}$ exposure and non-accidental mortality among Asian populations. Continued investigations are encouraged to contribute to the health impact assessment and public health management of air pollution in Asian countries.

• Journal of Preventive Medicine and Public Health
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• v.36 no.1
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• pp.47-53
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• 2003

Objectives : I used a case-crossover design to investigate the association between air pollution, and hospital admissions for asthmatic children under the age of 15 years in Seoul, Korea Methods : I estimated the changes in the levels of hospitalization risk from theinterquartile (IQR) increase in each pollutant concentrations, using conditional logistic regression analyses, with controls for weather information. Results : Using bidirectional control sampling, the results from a conditional logistic regression model, with controls for weather conditions, showed the estimated relative risk of hospitalization for asthma among children to be 1.04 (95% confidence interval (CI), 1.01-1.08) for particulate matter with an aerodynamic diameter less than or equal to 10m (IQR=40.4ug/m3); 1.05 (95% CI, 1.00- 1.09) for nitrogen dioxide (IQR=14.6ppb): 1.02 (95% CI,0.97-1.06) for sulfur dioxide (IQR=4.4ppb): 1.03 (95% CI, 0.99-1.08) for ozone (IQR=21.7ppb): and 1.03 (95% CI, 0.99-1.08) for carbon monoxide f10R=1.0ppm). Conclusions : This empirical analysis indicates the bidirectional control sampling methods, by design, would successfully control the confounding factors due to the long-term time trends of air pollution. These findings also support the hypothesis that air pollution at levels below the current ambient air quality standards of Korea is harmful to sensitive subjects, such as asthmatic children.

• Advances in environmental research
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• v.1 no.1
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• pp.57-68
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• 2012

Recent studies showed that air pollution is a risk factor for hospitalization for chronic obstructive pulmonary disease (COPD). However, there is limited evidence to suggest which subpopulations are at higher risk from air pollution. This study was undertaken to examine the modifying effect of specific secondary diagnosis (including hypertension, diabetes, pneumonia, congestive heart failure) on the relationship between hospital admissions for COPD and ambient air pollutants concentrations. Hospital admissions for COPD and ambient air pollution data for Taipei were obtained for the period from 1999-2009. The relative risk of hospital admissions for COPD was estimated using a case-crossover approach. None of the secondary diagnosis we examined showed much evidence of effect modification.

• Journal of Preventive Medicine and Public Health
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• v.39 no.4
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• pp.309-316
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• 2006

Objectives: Korean epidemiological studies have used reduced samples according to the subject's characteristics, such as the health services provided, the historical note with asthma, and age, to examine the acute effect of air pollution on asthma using the Korean National Health Insurance records. However, there have been few studies on whether the effects shown in these reduced samples are different from those of all samples. This study compared the effects of air pollution on asthma attacks in three reduced samples with those of entire samples. Methods: The air pollution data for $PM_{10},\;CO,\;SO_2,\;NO_2,\;and\;O_3$, and weather conditions including temperature, relative humidity, and air pressure in Seoul, 2002, were obtained from outdoor monitoring stations in Seoul. The emergency hospital visits with an asthma attack in Seoul, 2002 were extracted from the Korean National Health Insurance records. From these, the reduced samples were created by health service, historical notes with asthma, and age. A case-crossover design was adopted and the acute effects of air pollution on asthma were estimated after adjusting for weather, time trend, and seasonality. The model was applied to each reduced sample and the entire sample. Results: With respect to the health service, the effects on outpatients were similar to those for the total sample but were different for inpatients. These similar effect sizes were also observed in the reduced samples according to the historical note with asthma and age. The relative risks of $PM_{10},\;CO,\;SO_2,\;NO_2,\;and\;O_3$, among the reduced and entire samples were 1.03, 1.04-1.05, 1.02-1.03, 1.04-1.06, and 1.10-1.17, respectively. Conclusions: There was no clear evidence to show a difference between the reduced samples and the entire samples.

• Journal of Korea Entertainment Industry Association
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• v.14 no.6
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• pp.151-160
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• 2020

In the past, musicians followed strict patterns written by composers when playing classical music. However, since the development of postmodernism, which puts an emphasis on unique individualities and various ways of thinking, following the strict patterns of classical music unquestioningly became less significant. Classical music was thought to be difficult to follow and enjoy for most people. Thus, musicians have found ways to keep the dignity of classical music but added familiarity in order to popularize arias in operas. They created classical crossover music and this type of music enabled people to enjoy easy access to classical music. However, not many studies focus on arrangement methods of changing classical music into crossover music. The goal of this study is to research on arrangement methods of crossover music based on the findings from precedent researches on operas. This study focused on analyzing musical structure including chords, rhythms and compositions of musical instruments. According to the analysis, original classical songs and popera, which is a type of crossover music, share similarities in terms of rhythms and chords. However, there are differences when it comes to compositions of musical instruments. In case of a jazz version, it uses AfroCuban rhythm as well as Bolero rhythm which is a part of ballad and jazz acoustic instruments are mainly used. Also, in order to reduce the feeling of classical music and to differentiate the jazz version from the original version, a lot of tension is used in voicing. This study can be helpful for any researches related to arrangements of classical crossover music.

• Korean Journal of Biological Psychiatry
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• v.19 no.4
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• pp.159-163
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• 2012

An appropriate research design for hypotheses and purposes leads to a good quality of research results. In this review article, we summarized the types of research methods and described the characteristics of clinical trials. Research designs are categorized into observational studies and experimental ones, depending on data collecting methods. In an observational study, there are cross-sectional, cohort and case-control studies. Parallel groups design and crossover trial studies are representative designs in a randomized controlled trial study, a kind of experimental study. Clinical researchers should understand the characteristics of clinical research designs including advantages and disadvantages and choose the suitable design according to their study purposes and the nature of collected data or subjects.

• Journal of Navigation and Port Research
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• v.31 no.7
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• pp.605-611
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• 2007

In order to become a mega hub port, major ports all over the world are making every effort to enhance their productivity through efficiency of internal operation. Accordingly, in order to enhance the competitiveness of a container terminal, an automated container terminal is considered as the best alternative. An automated container terminal is using such automated handling equipment as AGV(Automated Guided Vehicles) and ATC(Automated Transfer Crane). The efficient equipment operation plays a critical role in enhancing the productivity of an automated container terminal. In an automated container terminal, the most important equipments are AGV and ATC. Each block of containers with a vertical layout is generally operating two ATCs. The two ATCs can be crossed or not at each block. In the case of operating crossover ATC, it has an advantage of high flexibility that ATC work is possible at both TP(Transfer Point) of each block. But it has also a disadvantage that the yard has to be operated at a low storage level of containers in the terminal yard. Recently, for automated container terminals, which are being prepared for opening in Korea, they plan to use uncrossed twin ATC in order to make the storage level of their yards high at a low cost. Therefore, studies have to be made in order to increase the efficiency of twin ATC system based on the flexibility that the crossover ATC system has. This research aims to suggest an operation strategy to improve efficiency of twin ATC at each storage block in a yard.

• Journal of agricultural medicine and community health
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• v.31 no.2
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• pp.119-144
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• 2006

The Korea rural health study, a large prospective cohort study, the objectives of this study are exploration for potential causes of agricultural injuries and diseases among farmers. Current medical research suggests that they may have higher rates of some traumatic injuries, pesticide poisoning, infectious diseases, musculoskeletal diseases, asthma and other respiratory diseases. This study is designed to identify occupational, lifestyle, and environmental factors of workplace that may affect the rate of diseases in farming population. Round 1, initial cohort recruitment, will begin in 2006 and conclude in 2009. Round 2, follow-up will begin in 2010 and conclude in 2014. Approximately 54,000 persons will be selected to study population. Nested case-control studies and case-crossover studies will be conducted for getting to the bottom of agriculture-related diseases. Recruitment and follow-up are conducted in collaboration with multi-centers. As data on the exposures and health outcomes of this study population are collected and analyzed in 2014. This study will be evaluated by public health experts for effort, achievement, adequacy of performance, efficacy, process of study and so on. The author expects that this cohort study may reduce agricultural injuries and diseases and will provide information that agricultural workers can use in making decisions about their health. Also, this study will be significant basis for strengthening the competitiveness of agriculture in Korea.

• Journal of Korean Medical Science
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• v.33 no.49
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• pp.314.1-314.15
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• 2018

Background: Despite its growing significance, studies on the burden of disease associated with natural disasters from the perspective of public health were few. This study aimed at estimating the national burden of disease associated with typhoons and torrential rains in Korea. Methods: During the period of 2002-2012, 11 typhoons and five torrential rains were selected. Mortality and morbidities were defined as accentual death, injury and injury-related infection, and mental health. Their incidences were estimated from National Health Insurance Service. Case-crossover design was used to define the disaster-related excess mortality and morbidity. Disability-adjusted life years (DALYs) were directly assessed from excess mortality and morbidity. Results: The burden of disease from typhoons increased with the intensity, with 107.7, 30.6, and 36.6 DALYs per 100,000 per event for strong, moderate, and weak typhoons, respectively. Burden of disease from torrential rains were 56.9, 52.8, and 26.4 DALYs per 100,000 per event for strong, moderate, and weak episodes, respectively. Mental disorders contributed more years lived with disability (YLDs) than did injuries in most cases, but the injury-induced YLDs associated with strong typhoon and torrential rain were higher than those of lower-intensity. The elderly was the most vulnerable to most types of disaster and storm intensities, and males younger than 65 years were more vulnerable to a strong torrential rain event. Conclusion: The intensity of torrential rain or typhoon was the strongest determinant of the burden of disease from natural disasters in Korea. Population vulnerable may vary depending on the nature and strength of the disasters.

• Steel and Composite Structures
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• v.7 no.6
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• pp.421-440
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• 2007

An optimal design method in cooperated with nonlinear inelastic analysis is presented. The proposed nonlinear inelastic method overcomes the difficulties due to incompatibility between the elastic global analysis and the limit state member design in the conventional LRFD method. The genetic algorithm used is a procedure based on Darwinian notions of survival of the fittest, where selection, crossover, and mutation operators are used to look for high performance ones among sections in the database. They are satisfied with the constraint functions and give the lightest weight to the structure. The objective function taken is the total weight of the steel structure and the constraint functions are load-carrying capacity, serviceability, and ductility requirement. Case studies of a planar portal frame, a space two-story frame, and a three-dimensional steel arch bridge are presented.