• 근관절건강학회지
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• 제17권2호
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• pp.173-182
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• 2010

Purpose: The purpose of this study was to examine levels of pain, depression, and adjustment to military life in soldier who experienced low back pain, in order to produce fundamental data for the development of health improvement programs to prevent and manage low back pain in soldiers with low back pain. Methods: Subjects of this study consisted of 317 soldiers who had low back pain. Study instruments were Visual analog scale (VAS), the Center for Epidemiological Studies-Depression Scale (CES-D), and adjustment to military life scale. Collected data were analyzed by the SPSS Win 14.0 program. Results: Mean score of pain was 4.16 points, depression was 8.58 points, and adjustment to military life was 69.15 points. The level of pain was negatively related to adjustment to military life (r=-.241, p<.001) and positively related to depression (r=.262, p<.001). There was a negative relationship between depression and adjustment to military life (r=-.442, p<.001). Conclusion: Soldiers who had low back pain experienced higher levels of pain and depression and lower level of adjustment to military life. Therefore, further study is needed to develop and examine a nursing intervention to manage low back pain for them.

• Physical Therapy Rehabilitation Science
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• 제10권2호
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• pp.90-97
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• 2021

Objective: The purpose of this study was to find out how the back instability during clam exercise (CE) causes changes in pelvic rotation and hip joint abductor muscle activity, and to find out the effects with different methods of application of pressure biofeedback. Design: Comparative study using repeated measures. Methods: Each subjects performed the clam exercise (CE) without pressure biofeedback, the clam exercise with pressure biofeedback applied to the back (CE-PBU to back), and the clam exercise with pressure biofeedback applied to the side (CE-PBU to side). The amount of pelvic rotation was measured using myomotion. And the muscle activity of the muscle gluteus medius and the tensor fasciae latae was measured using EMG device. One-way repeated measures ANOVA followed by the Bonferroni post test were used to compare the EMG activity in each muscle and pelvic rotation angle during the CE, CE-PBU to back, CE-PBU to side. Results: The amounts of pelvic rotation was the lowest in CE-PBU to back (p< 0.05) and the ratio of muscle activity of the muscle gluteus / tensor fasciae latae was the highest in CE-PBU to back (p< 0.05). Conclusions: It is thought that, in order to stabilize the waist-pelvis and increase hip joint muscle strength in subjects with back instability, applying clam exercise with pressure biofeedback applied to the lower back is effective in improving waist-pelvic movements and selectively strengthening the muscle gluteus medius.

• 한국추진공학회지
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• 제18권3호
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• pp.40-47
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• 2014

우주발사체 최적 설계에 사용될 내탄도 해석 코드를 위한 그레인 Burn-back 연구를 수행하였다. 그레인 Burn-back은 내탄도 해석에 필수적인 그레인의 연소면적의 계산에 사용된다. 최적 설계에 사용될 내탄도 해석 코드는 설계 변수의 변경 및 반복계산을 통해 요구 성능을 만족할 때 까지 반복 계산을 수행한다. 따라서 내탄도 해석에 적용될 Burn-back 해석기법은 설계 변수의 변경이 용이하며 계산시간이 짧아야 한다. 이에 본 연구에서는 Analytical Method를 이용하여 Burn-back 해석코드를 개발하였으며, 그레인 형상에 대해 기하학적 변수를 선정 및 형상 변화에 대해 정리하였다. 개발된 코드는 Numerical Method로부터 산출된 값과 비교하여 검증을 수행하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.317-320
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• 2004

The exponential back-off algorithm doubles the back-off size after each collision without considering network traffic status, which causes degradation of system performance. In this paper, we propose a linear random back-off mechanism which dynamically selects the back-off window size based on the channel status which includes the number of active stations and collisions to significantly increase the protocol capacity. We present an analytical model for the saturated throughput of our linear random back-off algorithm. Simulation results show that performance can be substantially enhanced if binary exponential back-off algorithm is replaced by a linear back- off algorithm.

• PNF and Movement
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• 제10권2호
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• pp.17-24
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• 2012

Purpose : The purpose of this study was to describe the Intervention strategy applied ICF Tool on patient with low back pain. Methods : The data was collected by low back pain patient. We applied the ICF Tool for low back pain patient. Parameters of result were collected for using the VAS, 6 minute walk test and ICF assessment sheet. Results : Significant differences were observed the low back pain patient for VAS, 6 minute walk test and ICF assessment sheet. low back pain patient improved all test. Conclusion : ICF Tool applied Intervention about low back pain patient is very useful and effective. It is effective in clinical practice.

• Journal of Power Electronics
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• 제12권4호
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• pp.604-614
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• 2012

This paper presents a comparative study of position sensorless control schemes based on back-electromotive force (back-EMF) estimation in permanent magnet synchronous motors (PMSM). The characteristics of the estimated back-EMF signals are analyzed using various mathematical models of a PMSM. The transfer functions of the estimators, based on the extended EMF model in the rotor reference frame, are derived to show their similarity. They are then used for the analysis of the effects of both the motor parameter variations and the voltage errors due to inverter nonlinearity on the accuracy of the back-EMF estimation. The differences between a phase-locked-loop (PLL) type estimator and a Luenberger observer type estimator, generally used for extracting rotor speed and position information from estimated back-EMF signals, are also examined. An experimental study with a 250-W interior-permanent-magnet machine has been performed to validate the analyses.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.310-315
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• 2000

We analyzed thermal stress of the STS VOD ladle by the variation of material property of refractory, and determined the location of back filler using FE analysis. Thermal distribution of refractory of ladle between hot face and back face were decreased by the increasing the thermal conductivity, and thermal stress of refractory were decreased about 2 to 4 times with the decreasing the young's modulus coefficients. Back filler, which is constructed to absorb the thermal expansion of dolomite refractory, has relatively low thermal conductivity. Inner side of refractory of ladle maintained high temperature, but temperature of outer side of ladle decreased low. Consequently, inner expansion and outer contraction were appeared. and thermal stress were increased, so thermal stress by the construction of back filler were increased.

• 소성∙가공
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• 제20권6호
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• pp.461-467
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• 2011

An artificial body force method is presented to accurately simulate drawing processes in which back pressing is exerted. A rigid-plastic finite element method is applied together with a numerical scheme to eliminate the numerically incurred plastic deformation in rigid or elastic region, which significantly influences simulation results because it eventually changes reduction of area in drawing. Back tension or compression is applied by body force at the rear part of material to obtain numerically stable solution. Two typical examples are shown, a drawing process with back tension applied and a tube drawing with a fixed plug and back pressing applied.

• The Journal of Korean Physical Therapy
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• 제3권1호
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• pp.123-149
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• 1991

This study has been attempted to be helpful for the back rehabilization of Korean workers by analyzing the general, occupational, social aspects of low back pain and to identify possible risk factors for back pain in White and Blue collar workers. The primary data were collected from 380 workers in Seoul city by means of a Questionnaire with random which was distributed from March 10 to 31, 1990. For the test of statistical significance, chi-square analysis was used to compare the back pain characteristics between above two groups. The results were as follows : 1. The incidence of low back pain in all walkers studied was $79.7\%$. The incidence of Blue collar with low back pain $(87.2\%)$ was higher than that of White collars $(75.0\%)$. 2. With regard to the relationship of back pain to the occupational characteristics, statistically significant differences were observed between workers with and without back pain concerning the job factors on work-time, job satisfaction, mental stress, chair fittness, work posture, work rotation, weight lifting, monotonous repetitive movements, vibration, and heavy noise (p<0.05). 3. With regard to the relationship of back pain to the social characteristics, there were no differences with respect to having car, personality types, drinking habits, and leisure-time activities. However, significant differences were showed between no pain and pain groups for the using bed, sleeping posture, traffic time amount, walking health state, smoking habits, and physical exercise (p<0.05). 4. The comparative analysis of back pain related to work factors showed highly significant differences with respect to mental stress, chair fittness, work posture, trunk rotation, weight lifting, monotonous repetitive work in White collar group (p<0.01) ; and job satisfaction, mental stress, trunk rotation, weight lifting, monotonus repetitive work, exposure to vibration and heavy noise in Blue collar group(p<0.01). 5. The comparative analysis of social factors in two groups showed differences with respect to the using bed, sleeping posture, walking amount, health state, physical exercise, smoking habits in White cellar group (p<0.05) ; and walking amount, traffic time amount, health state, smoking habits, physical exercise in Blue cellar group (p<0.05). 6. In regard to the general aspects of back pain between two groups, there were differences concerning etiolgy of back pain, counselling partners, treatment types, and sick-leaves(p<0.05), except pain duration, and awareness of back pain.

• The Journal of Korean Physical Therapy
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• 제25권1호
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• pp.10-15
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• 2013

Purpose: Low back pain occurs and frequently recurs in many people. An imbalance of paraspinal muscle activity can cause low back pain. Mulligan's concept of mobilizations with sustained natural apophyseal glides (SNAG) is a common method for treating low back pain. The purpose of this study was to investigate the effects of this method on paraspinal muscle activity in patients with chronic low back pain. Methods: Twenty-one patients with low back pain participated in this study. Patients were classified using the Oswestry disability index. The subjects' paraspinal muscles were measured by surface electromyography both before and after the SNAG mobilization. We measured the root mean square value of the paraspinal muscles during lumbar flexion and extension. Results: Paraspinal muscle activity in patients with chronic low back pain was different between the right and left sides. Importantly, paraspinal muscle activity significantly decreased after using the SNAG mobilization method. Conclusion: This study shows a difference between paraspinal muscle activity in chronic low back pain patients and finds that the Mulligan's concept of SNAG mobilization is effective at reducing imbalances in paraspinal muscle activity in low back pain patients.