• Journal of the East Asian Society of Dietary Life
• /
• v.4 no.2
• /
• pp.17-26
• /
• 1994

This study was an attempt to investigate various factions, such as the calorie, nutrient intake, physical activity, blood lipids, obesity prevalence and body fat distribution on NIDDM male diabetics. General characteristics, physical activity and exercise levels of subjects were invesigated by interviewing, daily calorie and nutrient intake were measured by convenient method. The following anthropometric measurements were made on all participats : weight, height. Also waist and hip circumference were measured on 174 male diabetics to get waist-to-hip circumference ratio as index of the body fat distribution. For measurement of plasma lipids, 12-hour fasting blood samples were drawn The results of this study were summarized as follows : 1. At the onset of diabetes, the major self-diagnosed symptoms were polydipsia, fatigue, and body weight redution 2. The average of daily energy intake of male diabetics was 2106 Kcal which is 96% of the RDA Percentage of energy is that carbohydrate:protein : pat=70:14:16. 3. Among the NIDDM male subjects, 59% was exercise regularly. 4. Obese subjects above in the ideal body weight of 120% are presently 17%, but 39% of subjects were reported to be obese in the past. The mean BMI of the male NIDDM diabetics is 23.3${\pm}$2.6 and the past mean BMI was 25.2${\pm}$2.7 The mean WHR was 0.93${\pm}$0.10. 5. When diabetics were divided into obese and nonobese group according to RBW, energy intake, blood pressure, blood glucose and total cholesterol were not significantly different between the two groups, but LDL and VLDL-cholesterol were significantly higher in the obese group. 6. RBW did not correlate with cholesterol and triglyceride, but WHR correlated significantly with cholesterol and triglyceride. In conclusion, these results from a present study support previous findings indicating that not only the degree of obesity but also the localization of fat is a risk factor for diabetes.

• Journal of Environmental Health Sciences
• /
• v.40 no.5
• /
• pp.376-384
• /
• 2014

Objective: The purpose of this study is to compare the health status of residents who were exposed to sources of extremely low frequency electromagnetic fields (ELF-EMFs) in the living environment and those who were not exposed to such a source of ELF-EMFs through a survey designed to appraise the residents' health levels. Method: Aimed at 251 residents exposed to a source of ELF-EMFs and 278 residents not exposed to a source, the survey was conducted to investigate the health status of the residents on the basis of questionnaire SF-36. Result: The health status scores of residents exposed to ELF-EMFs turned out to be lower than those of their counterparts. In terms of self-reported symptoms related to health and sleep quality, residents exposed to ELF-EMFs were found to have a higher complaint rate of self-reported symptoms such as dizziness, depression, and fatigue. Regarding sleep disorders, residents exposed to ELF-EMFs appeared to have a slightly higher complaint rate of sleep disorders compared to non-exposed residents. Conclusion: If a region is to be exposed to a source of ELF-EMFs, a more proactive policy for reducing such exposure is advised. In addition, it is necessary to better understand problems of residents by emplacing an ELF-EMFs risk information delivery system and building an efficient communication system for voluntary participation during the construction phase.

• Journal of the Ergonomics Society of Korea
• /
• v.28 no.1
• /
• pp.9-19
• /
• 2009

Repetitive movement, inadequate working posture, overuse of force, physical contact with sharp edge, vibration and temperature were well known risk factors of WMSDs (Work-related Musculoskeletal Disorders). Many researchers have investigated the relationship between inadequate working postures and incidences of WMSDs of the upper extremities, whereas relatively few researchers have tried to evaluate workload associated with the lower-body postures. The effects of lower-limb postures including various knee flexion angles on the subjective discomfort, heart rate and EMG of lower-limb muscles were investigated in this study. Thirty graduate students were asked to maintain thirteen different body postures, and heart rate and EMG data of five muscle groups (electro spine, biceps femoris, vastus medialis, gastrocnemius and tibialis anterior) from each posture were collected during fifteen minutes sustaining tasks. All participants were also asked to report their discomfort ratings of body parts. Results showed that high subjective discomfort ratings and heart rates were reported at the postures of knee angles of $60^{\circ}$ and $90^{\circ}$, whereas low discomfort ratings were founded at the postures of chair heights with 20cm, 40cm, and sitting with crossed legged. The change of median frequency for each muscle group during fifteen minutes tasks was investigated for each body posture to evaluate the relationship between muscle fatigue and body posture. It was found that the trends of changes of median frequency were different based on muscle group as well as lower-limb body posture from this study.

• Journal of the Korean Society for Railway
• /
• v.14 no.6
• /
• pp.535-544
• /
• 2011

The rail surface defects can cause the high impact load on the track and lead to the progress of the rail fatigue damage and the rail break. In case of the rail break, there is a great deal of risk for derailment, and thus the maintenance criteria for the rail surface defects are of great importance. In this study, using the dynamic train-track interaction analysis program, the impact wheel loads and rail bending stresses according to the depths of the surface defects have been calculated with the input data of the rail surface irregularities measured at 43 spots with surface defects in the ballasted track of high-speed railway. Considering the irregularity of track geometry, the allowable limits of wheel load and rail bending stress have been set, and the maintenance criteria for the rail surface defects was suggested by analyzing the relationship of the maximum values of wheel load and rail bending stress versus depth and width of rail surface defect. The analysis results suggest that the allowable depth of the surface defect is determined approximately 0.2mm from the limit of the impact wheel load.

• Safety and Health at Work
• /
• v.9 no.1
• /
• pp.42-52
• /
• 2018

Background: Maintenance operations on-board ships are highly demanding. Maintenance operations are intensive activities requiring high man-machine interactions in challenging and evolving conditions. The evolving conditions are weather conditions, workplace temperature, ship motion, noise and vibration, and workload and stress. For example, extreme weather condition affects seafarers' performance, increasing the chances of error, and, consequently, can cause injuries or fatalities to personnel. An effective human error probability model is required to better manage maintenance on-board ships. The developed model would assist in developing and maintaining effective risk management protocols. Thus, the objective of this study is to develop a human error probability model considering various internal and external factors affecting seafarers' performance. Methods: The human error probability model is developed using probability theory applied to Bayesian network. The model is tested using the data received through the developed questionnaire survey of >200 experienced seafarers with >5 years of experience. The model developed in this study is used to find out the reliability of human performance on particular maintenance activities. Results: The developed methodology is tested on the maintenance of marine engine's cooling water pump for engine department and anchor windlass for deck department. In the considered case studies, human error probabilities are estimated in various scenarios and the results are compared between the scenarios and the different seafarer categories. The results of the case studies for both departments are also compared. Conclusion: The developed model is effective in assessing human error probabilities. These probabilities would get dynamically updated as and when new information is available on changes in either internal (i.e., training, experience, and fatigue) or external (i.e., environmental and operational conditions such as weather conditions, workplace temperature, ship motion, noise and vibration, and workload and stress) factors.

• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.15 no.1
• /
• pp.62-70
• /
• 2019

The APR1400 reactor may be operated for a long time under high temperature and pressure conditions, causing damage to the stud holes and causing stud bolts and holes to stick. The present practice is to manually remove the anti-sticking agent and foreign matter remaining in the APR1400 reactor stud hole and to visually check the surface condition of the thread to check the damage status of the threads. In the case of the APR1400 reactor stud holes, manually cleaning the threads increases the risk of radiation exposure and operator's fatigue. To avoid this, the autonomous mobile robot is used to automatically clean the reactor stud holes. The purpose of this study is to optimize the cleaning performance of the mobile robot by looking at the behavior of the surface roughness of the stud surface cleaned by the brush attached to the mobile robot due to changes in brush material, thickness of wire, and rotation speed. A microscopic approach to the surface roughness of the flank is needed to investigate the effects of the newly proposed brush of the autonomous mobile robot on the thread holes. According to this experiment, it is reasonable to use STS brush rather than Carbon one. Optimal operating conditions are derived and the safety of APR1400 reactor stud holes maintenance can be improved.

• Journal of Ocean Engineering and Technology
• /
• v.33 no.5
• /
• pp.435-446
• /
• 2019

Because offshore structures are affected by various environmental loads, the risk of damage is high. As a result of ever-changing ocean environmental loads, damage to offshore structures is expected to differ from year to year. However, in previous studies, it was assumed that a relatively short period of load acts repeatedly during the design life of a structure. In this study, the residual life of an offshore wind turbine support structure was evaluated in consideration of the timing uncertainty of the ocean environmental load. Sampling points for the wind velocity, wave height, and wave period were generated using a central composites design, and a transfer function was constructed from the numerical analysis results. A simulation was performed using the joint probability model of ocean environmental loads. The stress time history was calculated by entering the load samples generated by the simulation into the transfer function. The damage to the structure was calculated using the rain-flow counting method, Goodman equation, Miner's rule, and S-N curve. The results confirmed that the wind speed generated at a specific time could not represent the wind speed that could occur during the design life of the structure.

• Design & Manufacturing
• /
• v.14 no.4
• /
• pp.17-24
• /
• 2020

Products for heating indoors in low temperature and dry winter are largely divided into products using fossil fuels and products using electricity. The fossil fuels can warm the entire space by convection, but there is a high risk of fire and the frequent ventilation due to the increase in carbon monoxide and carbon dioxide. Heaters using electricity are mainly used because they are convenient to use and are cheap. However, these products can not efficiently warm the air because they use radiation energy. In other words, only the front part exposed to the heater is warm, and the rear part has no heating effect at all. Also, because it emits a large amount of light, fatigue of the eyes is very high. Another problem is that when using electric heaters, the room tends to be dry by high heat. Indoor humidity maintenance is a very important factor in the prevention and treatment of respiratory diseases. Especially, it is essential for health care for infants, bronchial organs and people with weak respiratory because humidity is low in winter. In this study, we conducted a study to develop a product that can improve heating efficiency while maintaining proper indoor humidity by combining heat energy and moisture particles. The concept of humidification and heating at the same time, moisture particles generated in the humidifier pass through the heater, include thermal energy, and the moisture particles with thermal energy are diffused into the space by forced convection, thereby warming the entire space. In addition, the heating time is shortened as the feeling temperature is increased with the high relative humidity, and this has the effect that the heating cost in winter is reduced.

• Journal of Ginseng Research
• /
• v.46 no.5
• /
• pp.657-665
• /
• 2022

Background: Sarcopenia is a new and emerging risk factor aggravating the quality of life of elderly population. Because Korean Red Ginseng (RG) is known to have a great effect on relieving fatigue and enhancing physical performance, it is invaluable to examine its potential as an anti-sarcopenic drug. Methods: Anti-sarcopenic effect of non-saponin fraction of Korean Red Ginseng (RGNS) was evaluated in C2C12 myoblasts treated with C2-ceramide to induce senescence phenotypes, and 22-month-old mice fed with chow diet containing 2% RGNS (w/w) for 4 further months. Results: The RGNS treatment significantly alleviated cellular senescence indicated by intracellular lipid accumulation, increased amount of lysosomal β-galactosidase, and reduced proliferative capacity in C2C12 myoblasts. This effect was not observed with saponin fraction. In an aged mouse, the 4-month-RGNS diet significantly improved aging-associated loss of muscle mass and strength, assessed by the weights of hindlimb skeletal muscles such as tibialis anterior (TA), extensor digitorum longus (EDL), gastrocnemius (GN) and soleus (SOL), and the cross-sectional area (CSA) of SOL muscle, and the behaviors in grip strength and hanging wire tests, respectively. During the same period, an aging-associated shift of fast-to slow-twitch muscle in SOL muscle was also retarded by the RGNS treatment. Conclusions: These findings suggested that the long-term diet of RGNS significantly prevented aging-associated muscle atrophy and reduced physical performance, and thus RGNS has a strong potential to be developed as a drug that prevents or improves sarcopenia.

• Journal of the Korean Society of School Health
• /
• v.35 no.3
• /
• pp.65-74
• /
• 2022

Purpose: The purpose of the study was to verify the degree of smoking behaviors including conventional cigarettes, electronic cigarettes, and dual use of conventional and electronic cigarettes among adolescents, and to explore associated intrapersonal and interpersonal factors of the three smoking behavior groups. Methods: The secondary data analysis was performed using the 17th 2021 Korea Youth Risk Behavior Survey. The types of smoking behaviors were grouped into conventional cigarettes, electronic cigarettes, and dual use for data analysis. Descriptive statistics and a χ² test were performed. Multinomial logistic regression analysis was conducted to identify factors associated with of the three smoking behavior groups. Results: Among the 54,848 adolescents, 3.6%, 1.2% and 6.2% were involved in conventional cigarettes, electronic cigarettes, and the dual use, respectively. The factors associated with the three types of smoking behaviors were depression, suicidal ideation, having a smoking mother, having smoking brothers or sisters, and having smoking friends. Recovery from fatigue by sleep was associated with the dual use of conventional and electronic cigarettes. Anxiety was associated with conventional cigarettes. Having a smoking father was associated with conventional cigarettes and dual use. Conclusion: A significant number of adolescents were involved in not only the use of conventional or electronic cigarettes, but also dual use of them. Adolescents who had depression, suicidal ideation, having a smoking friend, and having a smoking family member were more likely to be involved in the three types of smoking behaviors. Customized interventions to decrease smoking should be developed considering intrapersonal factors as well as interpersonal factors.