• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.2
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• pp.178-186
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• 2015

Endurance time is very important indicator to estimate muscle fatigue. In the case of measuring endurance time directly, it is dangerous for subject to perform a test until the point of failure to main time force. Therefore, this paper presents the model to estimate endirance time using indirect measurements such as personal factors and anthropometrical data. Previous studies had shown that personal factors such as gender and age were not related to endurance time, but recently studies have shown that it is estimated by using independent variable or predictor such as GTA (Gravitational Torque of the horizontal, stretched arm) and MVC (Maximum Voluntary Contraction). The present study investigated variables to estimate endurance time using personal factors and anthrometrical data during isotonic contractions. Twenty five healthy subject volunteered for this study, and performed three test sessions of isotonic contraction exercises at 10~50% respectively. Afterward the correlation coefficient and p-values were compared among regression models using personal factors and anthropometrical data. The results demonstrated that multi-regression model had significant coefficient of correlation, and was useful estimate endurance time.

• Journal of muscle and joint health
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• v.19 no.1
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• pp.16-26
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• 2012

Purpose: The purpose of this study was to investigate the effects of lumbar stabilization exercise on balance ability in patients with adolescent idiopathic scoliosis. Methods: This study was one group pretest-posttest design. Twenty young idiopathic scoliosis patients were recruited for this study. They had the lumbar stabilization exercise program for 40 minutes a day, three times per week for 3 weeks. The lumbar trunk muscle endurance test and clinical balance tests (functional forward reach, functional lateral reach, Fukuda 50-stepping, one leg standing with eyes open and eyes closed) were measured before and after the lumbar stabilization exercise. Results: There were significant differences between pre-and post-test in absolute value of the difference between right and left lateral reach, distance of Fukud 50-stepping and one leg standing on the each side with eyes closed(p<.05). The results showed that the lumbar trunk muscle endurance significantly increased(p<.05). Conclusion: In this study indicated that the lumbar stabilization exercise was effective on balance ability and lumbar trunk muscle endurance in patients with young idiopathic scoliosis.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.3
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• pp.423-431
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• 2016

In this study, wing design optimization for long-endurance unmanned aerial vehicles (UAVs) is investigated. The fluid-structure integration (FSI) analysis is carried out to simulate the aeroelastic characteristics of a high-aspect ratio wing for a long-endurance UAV. High-fidelity computational codes, FLUENT and DIAMOND/IPSAP, are employed for the loose coupling FSI optimization. In addition, this optimization procedure is improved by adopting the design of experiment (DOE) and Kriging model. A design optimization tool, PIAnO, integrates with an in-house codes, CAE simulation and an optimization process for generating the wing geometry/computational mesh, transferring information, and finding the optimum solution. The goal of this optimization is to find the best high-aspect ratio wing shape that generates minimum drag at a cruise condition of $C_L=1.0$. The result shows that the optimal wing shape produced 5.95 % less drag compared to the initial wing shape.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.3
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• pp.89-96
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• 2016

PURPOSE: The purpose of this study is to compare the effects of aerobic exercise and combination exercise on physical fitness, body composition, and depression and to observe the relationship between obesity and depression. METHODS: A total of 40 obese people were divided into an aerobic exercise group ($n_1$=20) and a combination exercise group ($n_2$=20) that was performed swiss ball exercise and aerobic exercise. Each group exercised three times per week for eight weeks. Outcome measures were basic physical fitness, body composition, and depression. RESULTS: After completion of the exercise, there was a significant difference in overall physical fitness factors of percentage body fat (%body fat), strength, muscle endurance, flexibility, cardiovascular endurance in the combination exercise group (p<.05). Strength, muscle endurance, flexibility, and cardiovascular endurance were more improved in the combination exercise group than aerobic exercise group (p<.05). However, changes of %body fat and psychological factor between the two groups were not significant. CONCLUSION: Combination exercise program has an effect on the solution of obesity in physical development and strength. Therefore, it seems to that use with better perform both aerobic exercise and Swiss ball exercise. In addition, the Swiss ball exercise, which is an easy, convenient and economical self-exercise that can be done at home, is recommended due to its positive effects on physical establishment and fitness.

• Tribology and Lubricants
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• v.21 no.6
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• pp.278-282
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• 2005

Deep groove ball bearing is installed in a control element of an integral nuclear reactor, where water is used as coolant and lubricant. This bearing is made of STS440C stainless steel for the raceways and the balls to use in radioactive environment and water. It is known that the retainer design affects ball bearing operability and endurance life, however there is no verified retainer design and material for water lubricated ball bearing. Four kinds of retainers are manufactured for the endurance test of water lubricated deep groove ball bearing. Three of them are commercially developed types and the other is designed for this research. It is verified that ball bearings with steel pressed and general plastic retainer can not survive to required life in the water, however bearings with machined type and cylinder type retainer can survive. This proves that one of the major design parameters for water lubricated ball bearing is retainer type and material. In this paper, experimental research of endurance test for water-lubricated ball bearing are reported.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.3
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• pp.1-7
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• 2015

In the present study, we conducted the research on the high efficiency propulsion system for the development of long-endurance UAV with an electric propulsion system. For the long endurance UAV, fair aerodynamic characteristics with the high efficiency of the propulsion system is required because the flight power and the duration time of the long-endurance UAV vary greatly depending on the efficiency of the propulsion system. Therefore, in this study, the tracking program which records the performance of motor, propeller was developed because of their wide variation in the efficiency depending on the using condition, and records from the existing flight test program were utilized to check the accuracy of the program we had developed. For the development of future long-endurance solar UAV, we confirmed the applied voltage of motor, the optimal rotation of propeller and the gear ratio of reduction gear in order to get the highest efficiency on the propulsion system at the optimal flying condition.

• Women's Health Nursing
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• v.11 no.1
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• pp.20-26
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• 2005

Purpose: The purpose of this study was to understand self confidence during delivery in laboring women and to identify the factors influencing self confidence for delivery. Method: The participants of the study were 166 women who were admitted to a delivery room at C hospital in Seoul from July 1 to October 31, 2002. Data was collected using a structured questionnaire, self confidence scale, anxiety scale, knowledge of childbirth scale and graphic rating scale. The data was analyzed by the SPSS PC+ program. For the analysis of collected data, frequency analysis, Pearson's correlation, multiple linear regression analysis and stepwise selection method was used. Result: Self confidence during delivery had negative correlation coefficients with anxiety, and positive correlation coefficients with endurance of pain, husband support during pregnancy, age and parity. Anxiety was the highest factor influencing self confidence for delivery(40.0%). Endurance of pain, husband support during pregnancy and age accounted for 49.0% of self confidence in laboring women. Conclusion: The factors influencing self confidence during delivery were anxiety, endurance to pain, husband support during pregnancy and age. Further studies need to be done to identify interventions for overcoming on anxiety, promoting endurance of pain, and increasing husband support during pregnancy.

• Journal of environmental and Sanitary engineering
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• v.24 no.4
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• pp.49-59
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• 2009

The purpose of this study was to examine the effects of an aquarobics exercise program on the physical fitness and blood lipids in elderly women. The subjects of the study were twenty-six elderly women enrolled in an Aquarobics exercise program consisting of 60 minutes per session, 3 times a week during the period of 12 weeks. The effects of the program were assessed using the instruments to measure physical fitness and blood lipids before and after the aquarobics exercise program. Data was collected between September and December in 2006, and analyzed by frequency, paired with a t-test, using a SPSS. The results were statistically significant in muscle strength, muscle endurance, flexibility, and cardiopulmonary endurance, but no significant differences were found in agility, total cholesterol, triglycerides and high density lipoprotein cholesterol. Aquarobics exercise can be an effective nursing intervention to improve muscle strength, muscle endurance, flexibility and cardiopulmonary endurance in elderly women.

• Physical Therapy Korea
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• v.10 no.2
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• pp.1-10
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• 2003

This study was carried out to help the comprehensive rehabilitation of spinal cord injuries by measuring propulsion force and endurance exerted on wheelchair handrims, and predicting the differences among three different rear axle positions. The BTE (Baltimore Therapeutic Exerciser) work simulator was used on 9 paraplegia to test the force and endurance during wheelchair propulsion. The 141 large wheel of the BTE work simulator and a standard wheelchair with removed handrims were used for simulating wheelchair propulsion. The neurological and demographical characteristics of the patients were collected by personal interviews and direct examinations. The Kruskal-Wallis test was used to compare force and endurance among the groups. The strongest maximum isometric strength was produced when the rear axle of the wheelchair and the acromion process were on the same coronal plane. Although there were no significant differences statistically, moving the rear axle forward did result in greater isotonic strength. The research suggests that better functional activity of persons with paraplegia is possible when the rear axle of the wheelchair is appropriately adjusted.

• Physical Therapy Korea
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• v.14 no.4
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• pp.35-43
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• 2007

The purpose of this study was to compare the static balance in a sitting position between a group with adolescent idiopathic scoliosis (AIS) and a normal aged-matched group. Forty-nine subjects were included in this study. Thirty-one healthy subjects and eighteen AIS subjects were participated. Each group was tested with the Lumbar Trunk Muscle Endurance Test (LTMET) and Balance Performance Monitor (BPM). The parameters for static balance were sway area, sway path, mean balance, maximum velocity, anterior-posterior angle, and left-right angle of each group with eyes opened and closed. Results from the LTMET showed significantly more increase in the normal group than in the AIS group in the flexor and extensor endurance. The BPM tested showed significantly difference beteen the groups in parameters of sitting balance such as maximum velocity and anterior-posterior sway angle. For the AIS subjects, there were no significant differences in all parameters of sitting balance between eyes opened and eyes closed. In comparisons of the groups with eyes opened there were no significant differences in all parameters of sitting balance. In comparisons of the groups with eyes closed there were significant differences in the sway area, maximum velocity, anterior-posterior sway angle and left-right sway angle. These results suggest that the AIS group relies much more on proprioception than on vision, and develops compensatory passive postures of the spine. Further study is needed to measure many AIS patients with morphologic and electromyographic data for clinical application.