• PNF and Movement
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• 제18권3호
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• pp.415-424
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• 2020

Purpose: This study aimed to compare changes in abdominal muscle thickness in different standing postures with a handheld load between subjects with and without chronic low back pain (CLBP). Methods: Twenty subjects with CLBP and 20 controls participated in this study. Ultrasound imaging was used to assess the changes in the thickness of the transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) muscles. Muscle thickness in three different standing postures (standing at rest, standing with loads, standing with lifting loads) was compared with the muscle thickness at rest in the supine position and was expressed as a percentage of change in the thickness of the muscle. Results: While standing with loads, the change in IO muscle thickness in the CLBP patients increased more significantly than in the pain-free controls (p < 0.05). The standing with lifting loads posture showed a significant increase in the change in thickness of the TrA compared with the standing with loads posture (p < 0.05). In addition, the standing with lifting loads posture showed a significant decrease in the change in the thickness of the EO when compared with the standing with loads posture (p < 0.05). Conclusion: The automatic activity of the IO muscle in subjects with CLBP increased more than that of the pain-free controls in the standing with loads posture. These findings suggest that IO muscle function may be altered in those with CLBP while standing with loads. Additionally, TrA the activation level was found to be associated with increased postural demand caused by an elevated center of mass.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2006년도 PARALLEL CFD 2006
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• pp.361-363
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• 2006

• 대한물리치료과학회지
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• 제17권3_4호
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• pp.29-39
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• 2010

Purpose: The purpose of this study was to examine the effect of foot position and lifting an object on muscle activity and foot pressure during sit to stand(STS) in hemiparetic patients. Methods: Fourteen patients participated in this study. Surface electromyography was used to collect muscle activity and foot pressure measurement system was used to analyze foot pressure in hemiparetic side. Three different foot position was assumed(anterior, neutral, posterior) in hemiparetic side. The repeated two-way analysis of variance and multiple comparisons were conducted to determine statistical significance with a significance level of 0.05. Results: The results were as follows. 1) Lower extremity muscle activity was significantly higher(p<0.05) in biceps femoris and tibialis anterior muscle during STS without holding an object. With changing positions of the affected foot, muscle activity was significantly increased (p<0.05) in vastus medialis and lateral gastrocnemius when the foot was positioned in posterior. 2) There was no significant difference(p>0.05) in foot pressure during STS with object holding and foot positioning. Conclusion: Muscle activity showed a significant increase when the foot was positioned in posterior in comparison to the muscle activity when the foot was in neutral or anterior position.

• Journal of Nutrition and Health
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• 제2권4호
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• pp.135-142
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• 1969

To investigate the influences of physical exercises on lipid metabolism in human, serum lipids were determined in swimming, weight lifting and wrestling athletes after loading their proper exercises for certain periods of time. Atherolipid numbers were also determined in these hardly exercising athletes. Besides same time, experimental studies were carried out in rats to see the effects of high-carbohydrate, high-lipid and high-protein diets of 1, 2, 4 and 8 weeks duration upon serum total cholesterol level after the physical exercises. The results obtained were as follows: 1. In studies with athletes, the serum concentration of various forms lipids and atherolipid number were increased for some periods of time by imposing physical exercises. 2. In experimental studies with rats, various dietary effect upon the serum total cholosterol level after loading physical exercises were as follow; on high-lipid diets, the serum level increased upto the 4th week and thereafter kept the same increased level until the 8th week; on high-carbohydrate diet, the level increased upto the 2nd week and extended to the 4th week with the same increased level, but somewhat decreased at the 8th week; and on the high-protein diet, the level increased upto the 2nd week, and decreased progressively from the 4th week.

• 한국화재소방학회논문지
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• 제27권3호
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• pp.85-93
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• 2013

본 연구에서는 소방대원이 수행하는 업무 중 중량물을 다루어야 하는 작업에 대한 분류 및 정량적 분석(NLE, 3DSSPP)을 수행하여 향후 소방대원의 중량물 관련 작업에 대한 위험도를 예측하고, 관련 위험도를 감소시키기 위한 기초 자료를 도출하고자 하였다. 도출된 위험도 등급은 위험도 점수가 3점부터 9점까지 총 7단계로 구성되었다. 가장 위험도가 높은 1등급은 나타나지 않았으며 인명구조 작업이 두 번째로 높은 2등급에 속하는 것으로 나타났다. 3등급은 파괴기구 활용, 환자 들어올리기작업 등으로 나타났다. 본 연구 결과들은 소방대원의 허리 부상을 포함하는 근골격계 질환 예방을 위한 작업방법 및 장비의 개선, 교육 프로그램의 개발에 기본 토대가 될 수 있다고 판단되며, 소방대원들의 근골격계 질환에 대한 지속적인 예방을 위해서는 본 연구의 골격을 토대로 한 추후 심층적인 조사와 연구가 시급하다고 사료된다.

• 한국전문물리치료학회지
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• 제24권2호
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• pp.1-8
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• 2017

Background: Individuals with spinal cord injury (SCI) rely on their upper limbs for body-lifting activity (BLA). While studies have examined the electromyography (EMG) and kinematics of the shoulder joints during BLA, no studies have considered foot position during BLA. Objects: This study compared the effects of different foot positions during BLA on the shoulder muscle activities, peak plantar pressure, knee flexion angle, and rating perceived exertion in individuals with SCI. Methods: The study enrolled 13 mens with motor-complete paraplegic SCI, ASIA (American Spinal Injury Association) A or B. All subjects performed BLA with the feet positioned on the wheelchair footrest and on the floor independently. Surface EMG was used to collect data from the latissimus dorsi, pectoralis major, serratus anterior, and triceps brachii. The peak plantar pressure was measured using pedar-X and the knee flexion angle with Image J. Borg's rating perceived exertion scale was used to measure the physical activity intensity level. The paired t-test was used to compare the shoulder muscle activities, peak plantar pressure, knee flexion angle, and rating perceived exertion between the two feet positions during BLA. Results: The activity of the latissimus dorsi, pectoralis major, serratus anterior, and triceps brachii and rating perceived exertion decreased significantly and the peak plantar pressure and knee flexion angle increased significantly when performing BLA with the feet positioned on the wheelchair footrest compared with on the floor (p<.05). Conclusion: These findings suggest that individuals with SCI may perform BLA with the feet positioned on the wheelchair footrest for weight-relief lifting to decrease the shoulder muscle activities and the rating perceived exertion and to increase the peak plantar pressure and the knee flexion angle.

• 한국구조물진단유지관리공학회 논문집
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• 제14권3호
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• pp.91-99
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• 2010

RC 구조물의 보강에는 여러 가지 보강공법이 사용되고 있으며 특히 외부강선 보강공법은 손상된 구조물을 보강하는 대표적인 공법이며 효율성, 용이성, 경제성의 면에서도 우수하다. 본 연구에서는 PSC 및 RC 거더에서 추가 손상 없이 충분한 보강효과를 얻을 수 있는 보강공법으로써 개선된 인양홀을 이용한 정착장치를 제안하였다. 2가지 유형의 새롭게 제안된 정착장치를 6개의 실험체의 적용하였고 기존의 정착장치를 3개의 실험체에 적용하였다. 한 개의 실험체는 보강효율을 판단하기 위하여 보강공법을 적용하지 않았다. 이들 정착장치의 거동을 분석하기 위하여 정적 재하 시험을 수행하였고 실험변수들은 정착장치의 형상, 강봉의 긴장정도와 강선의 설치형태이다. 각 실험체의 보강 효과를 조사하기 위해 처짐, 변형률 그리고 파괴양상을 기록하였으며 균열하중, 항복하중, 극한하중, 연성지수 그리고 강선의 응력을 분석하였다. 그 결과 제안된 인양홀을 이용한 정착장치는 기존의 정착장치보다 높은 보강효율을 보였으며, 에너지 개념을 이용한 연성도 평가에 따르면 충분한 연성을 확보하고 있음을 알 수 있었다.

• Journal of Power Electronics
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• 제16권4호
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• pp.1598-1611
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• 2016

In some special occasions with strict size requirements, such as mine hoists, improving the design accuracy of the forced-air cooling systems of NPC three-level inverters is a key technology for improving the power density and decreasing the volume. First, a fast power-loss calculation method was brought. Its calculation principle introduced in detail, and the computation formulas were deduced. Secondly, the average and dynamic power losses of a 1MW mine hoist acting as the research target were analyzed, and a forced-air cooling system model based on a series of theoretical analyses was designed with the average power loss as a heat source. The simulation analyses proves the accuracy and effectiveness of this cooling system during the unit lifting period. Finally, according to an analysis of the periodic working condition, the maximum power-loss range of a NPC three-level inverter under multi cycle operation was obtained and its dynamic power loss was taken into the optimized cooling system model as a heat source to solve the power device damage caused by instantaneous heat accumulation. The effectiveness and feasibility of the optimization design based on the dynamic power loss calculation of the maximum power-loss range was proved by simulation and experimental results.

• 토지주택연구
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• 제10권3호
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• pp.77-87
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• 2019

In Korea, the modular construction method was applied to the construction of facilities such as military barracks and school dormitories, beginning with the pilot project of Seoul New Elementary School in 2003. In 2017, public modular houses were supplied to Busan(Yongho-dong) and Seoul(Gayang-dong), and modular housing is expected to continue to be supplied in the future. However, there is no clear construction standard for the modular housing construction yet, and there are few cases where the infill modular system is applied. Therefore, this study established the work breakdown structure and proposed a standard process focusing on the infill modular system applied to the construction of Dujeong-dong modular house in Cheonan. Level 1 of the work breakdown structure by construction stage of Infill modular was defined as modular manufacturing, assembly, and finishing process. Level 2 was defined as preparation, modular production, modular infill, modular fixing, floor plastering, building finishing, and other site finishing. Level 3 is defined as 57 detailed unit work of infill modular construction. The standard process of infill modular is proposed for the assembly stage that is commonly applicable to infill modular housing construction. The results of this study can be used for the process plan, transportation plan, lifting plan of modular housing construction.

• Safety and Health at Work
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• 제8권4호
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• pp.356-363
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• 2017

Background: The aim of this study was to investigate which physical and psychosocial work demands were associated with excellent work ability in individuals with neck pain, and to investigate age and sex differences in these associations. Methods: The study sample was obtained from the Statistics Sweden cross-sectional Work Environment survey and consisted of workers who reported neck pain after work (N = 3,212). Results: The findings showed an association between excellent work ability and self-reported low exposure to lifting, twisted work posture, working with hands in shoulder level or higher, and leaning forward without support and combination of exposures containing these work demands. Low exposure to seated work and high demands showed a reversed association. The associations were present mainly among older workers and were generally stronger for men than for women. Conclusion: This study indicates that a lower level of physically demanding work is an important element to maintain excellent work ability, especially for the older worker with neck pain.