• Journal of Preventive Medicine and Public Health
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• v.41 no.3
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• pp.200-207
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• 2008

Objectives : This study examined whether serious psychological distress (SPD) is associated with occupational injury among US employees. Methods : The employed population aged 18-64 years was examined (n=101,855) using data from the National Health Interview Survey (NHIS) 2000-2003. SPD was measured using the Kessler 6-item Psychological Distress Scale (K-6), a screening scale designed to identify persons with serious mental illness. The predicted marginal prevalence of psychological distress and occupational injury with the adjusted odds ratio were estimated using multiple logistic regression analyses. Results : The age-adjusted 3-month prevalence of occupational injury was $0.80{\pm}0.12%$ in workers with SPD, which was 37% greater than in workers without SPD ($0.58{\pm}0.03%$). The odds of occupational injury in workers with SPD were higher compared to workers without SPD (OR=1.34, 95% CI=0.93-1.92), after controlling for sex, age, race, education, occupation, and activity limitation by at least one medical condition. Male, service and blue collar occupation, and activity limiation by co-morbidity showed significantly higher odds of occupational injury for workers with SPD. Conclusions : The findings suggest that SPD accounts for an increased likelihood of occupational injury among US employees. A further longitudinal study is needed to differentiate the mechanism or causal pathways linking individual injury risk at the workplace, SPD, and socioeconomic factors.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.2
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• pp.131-143
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• 2013

Vibration condition monitoring of low-speed rotational slewing bearings is essential ever since it became necessary for a proper maintenance schedule that replaces the slewing bearings installed in massive machinery in the steel industry, among other applications. So far, acoustic emission(AE) is still the primary technique used for dealing with low-speed bearing cases. Few studies employed vibration analysis because the signal generated as a result of the impact between the rolling element and the natural defect spots at low rotational speeds is generally weak and sometimes buried in noise and other interference frequencies. In order to increase the impact energy, some researchers generate artificial defects with a predetermined length, width, and depth of crack on the inner or outer race surfaces. Consequently, the fault frequency of a particular fault is easy to identify. This paper presents the applications of empirical mode decomposition(EMD) and ensemble empirical mode decomposition(EEMD) for measuring vibration signals slewing bearings running at a low rotational speed of 15 rpm. The natural vibration damage data used in this paper are obtained from a Korean industrial company. In this study, EEMD is used to support and clarify the results of the fast Fourier transform(FFT) in identifying bearing fault frequencies.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.1
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• pp.61-71
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• 2018

In the Internet of Things, in which plenty of devices have connection to each other, cryptographically secure Random Number Generators (RNGs) are essential. Particularly, entropy source, which is the only one non-deterministic part in generating random numbers, has to equip with an unpredictable noise source(or more) for the required security strength. This might cause an requirement of additional hardware extracting noise source. Although additional hardware resources has better performance, it is needed to make the best use of existing resources in order to avoid extra costs, such as area, power consumption. In this paper, we suggest an entropy source which uses a multi-threaded program without any additional hardware. As a result, it reduces the difficulty when implementing on lightweight, low-power devices. Additionally, according to NIST's entropy estimation test suite, the suggested entropy source is tested to be secure enough for source of entropy input.

• Analytical Science and Technology
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• v.14 no.2
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• pp.131-139
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• 2001

There is personal difference in the concentrations of trace elements in human hair according to human life or history suck as occupation, race, sex, age, food habit, social condition and so on. It is also found that the individual's deviation of elemental concentrations is reflecting the degree of environmental pollutants exposure to human body, intakes of food and metabolism. To compare the degree of accumulation in the hair tissue, human hair samples were collected from five positions of head and analyzed by non-destructive neutron activation analysis with and without washing according to IAEA's recommended method. Analytical quality control is performed using the certified reference material. The relative error of Cu, Cr, Na, Co, Mg, As, Se, Zn and those of Mn, Ca, Fe, Sr are within ${\pm}5%$ and ${\pm}10%$, respectively and the relative standard deviation of elements are within ${\pm}10%$. The deviations between the individuals and hair sampling positions were estimated. The deviation of individual was seven times more than that of positions. Under the defined condition, the difference and the correlation of elemental concentrations were compared with two different groups, office and factory workers. The result can be used as a fundamental data for human health and environment assessment.

• Journal of Life Science
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• v.31 no.9
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• pp.840-848
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• 2021

This study was conducted to estimate annual trends and the environmental effects in the racing records of Jeju horses. The Korean Racing Authority (KRA) collected 48,645 observations for 2,167 Jeju horses from 2002 to 2019. Racing records were preprocessed to eliminate errors that occur during the data collection. Racing times were adjusted for comparison between race distances. A stepwise Akaike information criterion (AIC) variable selection method was applied to select appropriate environment variables affecting racing records. The annual improvement of the race time was -0.242 seconds. The model with the lowest AIC value was established when variables were selected in the following order: year, budam classification, jockey ranking, trainer ranking, track condition, weather, age, and gender. The most suitable model was constructed when the jockey ranking and age variables were considered as random effects. Our findings have potential for application as basic data when building models for evaluating genetic abilities of Jeju horses.

• Journal of the Korean Institute of Navigation
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• v.19 no.3
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• pp.35-65
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• 1995

The development of Korean shipping industry is maybe defined into three development stages-industry fixing stage, industry coordinating stage, industry development stage-. The development of shipping industry has been depended on the geovernment/authority role such as shipping policy, system, law, rules and regulations. In 1983, Korean shipping industry reorganization and coordination by shipping authority have made our shipping industry on the stable condition together with each company's efforts. Today's world economic environment such WTO/UR negotiation results get this government role limited. According to the being reduced government role, each company's competitive advantage power becomes more important. Besides, korean shipping industry is exposed into the entire and bitter world competition. In order to win and prevent the world shipping competition, it is necessary to look out the competitive advantage power of Korean shipping industry. The first purpose of this study is the situation analysis for competitive advantage power of Korean shipping industry. The second is to compare with our shipping policies with foreign ones concerned with ship, cargo, crew, tax and others. But in order to compare with foreign shipping, this study need their shipping statistics data, this study has some limit of the foreign data. This study has been carried on the basis of the following items. 1. Shipping environment, 2. Ships and ship acquirement(shipbuilding/purchasing), 3. Oceangoing cargo and ship's stowage rate, 4. Human factor in shipping-crew, 5. The incomes and costs in finacial statements. We have some conclusions as following through the this study. First, Korean shipping industry environment-competitive disadvantage situation- has changed rapidly due to the shipping market opening, free market entering of foreign shipping. Second, Korean shipping is disadvantageous due to the high tax rate and financing conditions in connection with ship acquirement. In order to improve the competitive advantage power, the shipping tax system and ship financing conditions should be reviewed to profitable for owners. Third, but both world and Korean oceangoing cargoes quantity have been increased annualy, Korean ship's cargo stowage rate is being decreased. This is serious situation but Korean shipping take well use of foreign vessel with hire. It is recommended to take use of owner's vessel and hired ones in the long range view, considering the world shipping management. But the number of crew has been decreased by 2, 000~3, 000 annualy, it is desirable that the long sea-experienced crew have been increased. Almost of owners usauly complain the crew cost is the main obstacles to competitive advantage power. Human factor is the most important firm's asset. All owners should pay attention to this though, and invest the proper budget to training, education, welfare as much as possible. In the long run this effects could be feedback to owners. Fifth, We must improve the financial statements structure, that is, the first step is to increase income, the second is to decrease cost, the third is to increase income on the same cost, the fourth is to decrease cost on the same income. It is essential to find out what the urgent investment is and what unnecessary cost is. At last, in order to competite world shipping race, each shipping firm must try for himself to retain the power. The government/authority is no longer dependable. I believe that each firm's power will be the industry's power, the industry's power will be the nations's power.

• The Journal of Korean Society for School & Community Health Education
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• v.20 no.3
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• pp.67-82
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• 2019

Objectives: The purpose of this study is to analyze how the different lifestyles between Koreans and Korean Americans have significant effects on their health. Despite being the same race, Koreans and Korean Americans have different health conditions and health attitudes due to the acquired environmental factors such as social-economic factors, lifestyle risk factors, healthcare systems, and medical utilization. It is crucial to examine how the different lifestyle habits between Koreans and Korean Americans lead to various health conditions for establishing an effective health promotion policy. Methods: In this study, a comparative analysis was conducted using the National Health and Nutrition Survey of Korea and CHIS data of the United States in 2005 and 2015 to provide valuable insights when establishing such a policy. Results: The specific research purpose is as follows: First, socioeconomic factors, such as (1)living habits risk factors, (2)health satisfaction levels, (3)disease outbreaks, and (4)medical uses, are analyzed to find the distinct characteristics among Koreans, Korean Americans, and Americans. Second, the three groups --Koreans, Korean Americans, and Americans-- were compared based on their exposure to disease-related lifestyle risk factors related to their body mass index and their general health condition. The research results are as follows: First, all three groups improved health conditions in 2015 better than in 2005. Koreans maintained relatively higher general health conditions compared to other groups: their prevalence rate of chronic diseases such as diabetes, high blood pressure, heart disease, and asthma was lower than that of U.S. residents. Second, in regards to health behavior factors, the lifetime smoking experience for Koreans and Americans both decreased in 2015 compared to 2005, while the lifetime smoking experience for Korean Americans increased slightly. The number of smokers for Koreans has greatly decreased over a decade while that of Americans has moderately increased. Third, according to the results of the multiple regression, the general health conditions, which is a dependent variable, suggests that the number of men who answered they are healthy is greater than that of women in Korea, compared to the United States. Conclusions: In conclusion, the acquired environmental factors had more significant impacts on health than the racial factors did. Compared to 2005, the health behaviors and health levels of Korean Americans in 2015 gradually became more similar to those of Americans.