• Journal of Korean Academy of Nursing
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• v.50 no.3
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• pp.401-410
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• 2020

Purpose: This study was performed to identify the prevalence of menstrual disorders in Korean women based on body mass index (BMI) and lifestyle factors, by utilizing the Korean National Health Insurance Database. Methods: A retrospective observational study design was used for the secondary data analysis. Data of women aged 15 to 49 years who were diagnosed with menstrual disorders were extracted from The National Health Insurance Service-National Health Screening Cohort in Korea from 2009 to 2016. The age-standardized prevalence rate of menstrual disorders was calculated using SAS version 9.4, and a Chi-square test and Cochran-Armitage test were performed. Results: In total, 2,219,445 cases were extracted from the database. The prevalence of menstrual disorders significantly increased from 8.6% to 11.6% (Z=135.16, p for trend <.001) over the past eight years. In particular, it was higher in underweight women than in women with normal weight across all years (Z=-4.18~-14.72, p<.001). Moreover, statistically significant differences in the prevalence of menstrual disorders were found to be associated with drinking and smoking in all years and with physical activity levels in part (p<.05~.001). Conclusion: These findings present compelling evidence on the prevalence of menstrual disorders based on a national database. Since the prevalence of menstrual disorders has steadily increased and differs based on BMI and lifestyle factors, educational and clinical interventions are necessary to promote risk awareness and appropriate behavioral changes among Korean women.

• Journal of Korean society of Dental Hygiene
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• v.18 no.1
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• pp.125-138
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• 2018

Objectives: The purpose of the study was to investigate the effect of gender in the association between the oral symptoms experience and health behavior. Methods: The subjects were 54,219 adolescents selected from the web-based survey of the 11th (2015) Korean Youth Risk Behavior of Korean Center for Disease Control. Data were analyzed using SPSS 18.0. The subjects consisted of 27,198 male students(50.2%) and 27,021 female students(49.8%) from 400 middle schools and 400 high schools. Results: Multiple logistic regression analysis after adjustment to demographic characteristics and oral health behavior showed experience with drinking and smoking in adolescents increased oral symptoms experienced by both male and female students (OR = 1.3, 95% CI = 1.20-1.34 / OR =1.3, 95% CI = 1.18-1.33), (OR = 1.3, 95% CI = 1.24-1.40 / OR = 1.4, 95% CI = 1.43-1.30). But the difference was not significant between genders. In terms of diet, consumption of carbonated beverages, snacks and fast food saw an increase in oral symptoms experience both gender compared with those whose "No(weekly)" in particular to women, alternatively vegetable, fruit consumption(weekly) were having less intake adolescents increase oral symptoms experience than "time daily(weekly)" intake adolescents both boy and girl especially to girl. Conclusions: There was a correlation between oral symptom experiences and health behaviors. There was also slight differences between genders, with more effect shown on female students. Based on this study, proper and systematic education of oral health management should be carried out at schools.

• Safety and Health at Work
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• v.8 no.3
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• pp.258-266
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• 2017

Background: Welders are exposed to many known and suspected carcinogens. An excess lung cancer risk among welders is well established, but whether this is attributable to welding fumes is unclear. Excess risks of other cancers have been suggested, but not established. We investigated welding cancer risks in the population-based Canadian Census Health and Environmental Cohort. Methods: Among 1.1 million male workers, 12,845 welders were identified using Standard Occupational Classification codes and followed through retrospective linkage of 1991 Canadian Long Form Census and Canadian Cancer Registry (1992-2010) records. Hazard ratios (HRs) were calculated using Cox proportional hazards models based on estimated risks of lung cancer, mesothelioma, and nasal, brain, stomach, kidney, and bladder cancers, and ocular melanoma. Lung cancer histological subtypes and risks by industry group and for occasional welders were examined. Some analyses restricted comparisons to blue-collar workers to minimize effects of potential confounders. Results: Among welders, elevated risks were observed for lung cancer [HR: 1.16, 95% confidence interval (CI): 1.03-1.31], mesothelioma (HR: 1.78, 95% CI: 1.01-3.18), bladder cancer (HR: 1.40, 95% CI: 1.15-1.70), and kidney cancer (HR: 1.30, 95% CI: 1.01-1.67). When restricted to blue-collar workers, lung cancer and mesothelioma risks were attenuated, while bladder and kidney cancer risks increased. Conclusion: Excess risks of lung cancer and mesothelioma may be partly attributable to factors including smoking and asbestos. Welding-specific exposures may increase bladder and kidney cancer risks, and particular sources of exposure should be investigated. Studies that are able to disentangle welding effects from smoking and asbestos exposure are needed.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.4
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• pp.137-146
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• 2016

In recent years, business environment is faced with multi uncertainty that have not been suffered in the past. As supply chain is getting expanded and longer, the flow of information, material and production is also being complicated. It is well known that development service industry using application software has various uncertainty in random events such as supply and demand fluctuation of developer's capcity, project effective date after winning a contract, manpower cost (or revenue), subcontract cost (or purchase), and overrun due to developer's skill-level. This study intends to social contribution through attempts to optimize enterprise's goal by supply chain management platform to balance demand and supply and stochastic programming which is basically applied in order to solve uncertainty considering economical and operational risk at solution supplier. In Particular, this study emphasizes to determine allocation of internal and external manpower of developers using S&OP (Sales & Operations Planning) as monthly resource input has constraint on resource's capability that shared in industry or task. This study is to verify how Stochastic Programming such as Markowitz's MV (Mean Variance) model or 2-Stage Recourse Model is flexible and efficient than Deterministic Programming in software enterprise field by experiment with process and data from service industry which is manufacturing software and performing projects. In addition, this study is also to analysis how profit and labor input plan according to scope of uncertainty is changed based on Pareto Optimal, then lastly it is to enumerate limitation of the study extracted drawback which can be happened in real business environment and to contribute direction in future research considering another applicable methodology.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.4
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• pp.89-100
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• 2020

In order to reduce the time and cost used in insurance processing, studies have been actively carried out to apply blockchain smart contract technology to car insurance. However, by using traffic data that is insufficient to prove accidents, existing studies are being exposed to the risk of insurance fraud, such as forgery and overstated damage by malicious insurers. To solve this problem, we propose an accident data-based reliability estimation model by using both various types of data through sensors, RSUs, and IoT devices embedded in automobiles and smart contracts. In particular, the regression model was applied in consideration of the weight estimation according to the type of traffic accident data and the reliability estimation model trained according to various accident situations. The proposed model is expected to effectively reduce fraud and insurance litigation while providing transparency in the insurance process and streamlining it is well.

• Journal of Environmental Science International
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• v.18 no.7
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• pp.781-796
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• 2009

The current standard level of Heat Health Watch Warning System consider both daily maximum temperature and daily maximum heat index(HI), but current standard could not consider daily maximum HI due to the difficulties in forecasting when we consider both daily maximum temperature and daily maximum HI and no considering HI because relative humidity could not observed for some regions. So, Newly established standard level of Heat Health Watch Warning System is based on daily maximum temperature exceeding $30^{\circ}C$ for two consecutive days or daily minimum temperature exceeding $25^{\circ}C$ and daily maximum temperature exceeding $30^{\circ}C$. These days are called "extreme heat days". On extreme heat days, the standard of extreme heat advisory is based on daily maximum temperature among exceeding $32.7^{\circ}C$ and not exceeding $34.8^{\circ}C$, and extreme heat warning is based on daily maximum temperature exceeding $34.8^{\circ}C$. ANOVA analysis was carried out using the data of Seoul Metropolitan City in 1994 to check the robustness of the new standard level of Heat Health Watch Warning System from this study, in particular for mortality variable. The results reveal that the new standard specifies excess mortality well, showing significance level of 0.05 in the difference of excess mortality for each phase.

• Journal of Preventive Medicine and Public Health
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• v.34 no.3
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• pp.253-261
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• 2001

Objectives : To evaluate the hypothesis that air pollution could increase emergency room visits for respiratory diseases, and if so, to quantify the strength of association between those. Methods : We compiled daily records of hospital emergency room visits for respiratory diseases in Seoul, from November 1. 1955 to October 31. 1996, by using medical utilization data of unscheduled visits. In addition, air quality and weather data for the same period was collected. And a case-crossover design was applied by adopting conditional logistic regression analysis to determine the relationship between air pollutants and emergency room visits for respiratory diseases. In particular, the control periods were chosen by a bidirectional paired matching technique 7, 14, and 21 days before and after the case periods. Results : Only ozone was associated with the increased number of emergency room visits for respiratory diseases. The relative risk according to a 30ppb increase of ozone concentration (24hr mean, lagged 1day) was 1.91(95% confidence interval = 1.78-2.05). Conclusion : There was a statistically significant association between the ambient ozone and daily emergency room visits for respiratory diseases.

• Korean Journal of Environmental Biology
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• v.22 no.4
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• pp.507-512
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• 2004

This study was focused on the risk assessment of whether radiofrequency electromagnetic fields generated by mobile phone is cytogenetically toxic or not. We conducted the effects of 835-MHz electromagnetic field (EMF) on DNA strand breaks in mouse thymic lymphoma L5178Y $Tk^{+/1-}$ cells using alkaline comet assay. EMF frequency 835-MHz we chosen is one of the most popular communication frequency bands in Korean code-division multiple-access (CDMA) mobile phone system. The cells were exposed to 835-MHz EMF alone or 835-MHz EMF combined with cyclophosamide(CPA) or 4-nitroquinoline-1-oxide (4NQO) at specific absorption rate (SAR) of 4.0 W $kg^{-l}$ for 24 and 48hrs. DNA damage expressed as tail moment was increased more than two-fold after exposure to 835-MHz EMF for 24 and 48hr. In particular, CPA for 48hr and 4NQO for 24 hr enhanced notably the tail moment to 9-fold and 16-fold in the presence of 835-MHz EMF, respectively, compared to each single treatment. From these results, it appears that exposure to CDMA-mobile phone radiation at 835-MHz frequency may potentiate DNA strand breaks of mouse thymic lymphoma L5178Y $Tk^{+/1-}$;cells under the defined conditions of this study.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.2
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• pp.575-579
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• 2016

The aim of this research is to determine the characteristics of endothelial factors and the hemostatic system conditions with malignant neoplasms patients, which were exposed to ionizing radiation. Total number of examined people is 223, 153 of them are patients with gastrointestinal tract oncopathology. The article presents the results of the analysis of numerical indicators of endothelial condition and platelet hemostasis of patients, who had cancer. They lived in the regions of Kazakhstan, subjected to contamination of radionuclides as a result of nuclear weapons tests, which took place in this region from 1949 to 1989. These results then were compared to cancer patients and healthy individuals with no radiation risk. The study revealed the presence of higher levels of endothelial dysfunction and following trigger of the hemostatic system in patients with malignant tumors of the gastrointestinal tract. In particular, the defined high degree of endothelial dysfunction include endothelium-dependent vasodilation, content desquamated endothelial cells in peripheral blood and von Willebrand factor. These indicators have a clear correlation with the degree of disorder of studied parameters of the hemostasis, which can cause the development of thrombotic complications.

• Journal of the Korean Institute of Navigation
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• v.12 no.1
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• pp.71-84
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• 1988

For traffic proceeding in random directions on a plane surface the frequency of collision, if no avoiding action in taken ,is approximately proportional to the square of the traffic density and directly proportional to the size and speed of the ship, Avoiding is normally taken and the rte of collisions is therefore also governed by additional factors such as the visibility, the effectiveness of the collisionavoidance rules, the competence of personnel or watchkeeping attitude, the maneuverability of the ship and the efficiency of radar and other equipments. From the viewpoint of watchkeeper who is responsible for maneuvering, watchkeeping attitude such as lookout and action to avoid collision is the most controllable factor among those mentioned above. In practice, according to the investigation of the institution of marine courts, about 50% co collisions occurred is caused by disorbedience to steering and sailing rules of international regulations for preventing collision at sea including lookout. So we classify the process of collisions with first sight of another ship , assessment of risk of collisions and action to avoid collisions and make a factural survey about lookout and action to avoid collisions from the point on "time" and " distance", namely relationship among ship's size, speed, first sight time of another ship, action to avoid collisions ,and distance from sight of another ship to collision occurred. According to the results of the actual survey , we come to conclude that most of collisions occurred are due to improper lookout and ineffective action to avoid collision which means time lag from first sight of another ship to time of action taken to avoid collision is relatively long. is relatively long.