• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.12 no.1
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• pp.1-15
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• 2006

Purpose: The purpose of this study was to evaluate the effects of abdominal muscle strengthening exercises and back muscle stretching on the flexibility of spinal column. Methods: The subjects were consisted of healthy adults ( 28 of females, 32 males; mean aged 21.6) from 18 to 29. All subjects randomly assigned to the control group, back muscle stretching group, abdominal muscle strengthening exercises group. back muscle stretching group received back muscles stretching for 20 minutes, abdominal muscle strengthening exercises group received abdominal muscle strengthening exercises for 30 minutes per day and 3 times a week during 3 week period. Spine motion analyzer (Spinal Mouse) was used to measure the flexibility of spinal column. All measurement of each subjects were measured at pre-experiment, after 10 days, and after 21 days. Results: The results of this study were summarized below 1. The sacral tilt angle of the hip joint of control group, back muscle stretching group, abdominal strengthening exercises group was no significantly differences at pre-experiment and after 10 days(p>0.5), but differency of each group occurred at after 21 days(p<0.5). the sacral tilt angle significantly increased at the back muscle stretching group, abdominal muscle strengthening exercises group, rather than the control group. 2. The thoracic vertebral tilt angle of the control group, back muscle stretching group, abdominal muscle strengthening exercises group was no significantly differences at pre-experiment, after 10 days, after 21 days(p>0.5). 3. The lumbar vertebral tilt angle of the control group, back muscle stretching group, abdominal muscle strengthening exercises group was no significantly differences at pre-experiment, after 10 days, after 21 days(p>0.5). 4. The spinal tilt angle of control group, back muscle stretching group, abdominal muscle strengthening exercises group was no significantly differences at pre-experiment and after 10 days(p>0.5), but differency of each group occurred at after 21 days(p<0.5). the spinal tilt angle significantly increased at the back muscle stretching group, abdominal muscle strengthening exercises group, rather than the control group(p<0.5). 5. The length of the spinal column of control group, back muscle stretching group, abdominal muscle strengthening exercises group was no significantly differences at pre-experiment and after 10 days (p>0.5), but differency of each group occurred at after 21 days(p<0.5). the length of the spinal column significantly increased at the back muscle stretching group, abdominal muscle strengthening exercises group, rather than the control group(p<0.5). Conclusion: these data suggests that 3-week abdominal muscle strengthening exercises and back muscle stretching improved the flexibility of sacrum, spinal column, and also improved spinal column lengthening. Additional randomized controlled trials to more fully investigate treatment effects and factors that may mediate these effects are needed.

• Journal of muscle and joint health
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• v.14 no.1
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• pp.5-12
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• 2007

Purpose: The purpose of the study was to identify the relationship between low back pain and job stress in hospital nurses. Method: A descriptive correlation research design was employed. The participants were 355 nurses who worked in a general hospital in W city Kangwon-do and consented to participate in this study. The Visual Analog Scale and job stress scale were used in this study. Analysis included descriptive statistics, t-test, ANOVA, and partial correlation coefficients. Results: Experience of low back pain for nurse in the past was 86.5% and in the present was 67.5% for low back pain which measured an average of 4.4 points for the level of low back pain. The mean score for job stress was relatively low(M=47.2). Job demand, organization system, job instability and conflict in relationships contributed to high stress scores, instead inappropriate compensation, job culture, and job autonomy contributed to low stress. There was a significant relationship between low back pain and job stress. Conclusion: These results suggest that further research is needed to develop programs to prevention and management of low back pain for nurses.

• Journal of East-West Nursing Research
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• v.21 no.2
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• pp.103-109
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• 2015

Purpose: The purpose of this study was to examine the effects of auricular acupressure therapy on back pain and lower abdominal pain in female undergraduate students during menstruation. Methods: The study used a quasi-experimental design. Data was collected from March 15th to June 31st, 2011. The participants were 20 female university students for the experimental group, and 22 female university students for the control group. visual analogue scale (VAS) with the opening records was used to assess back pain and lower abdominal pain. Data was analyzed using the ${\chi}^2$-test, Fisher's exact test, Mann-Whitney U test, and Wilcoxon signed rank test using the SPSS/WIN 11.0 program. Results: There were statistically significant differences in back pain and lower abdominal pain between the two groups. Auricular acupressure therapy decreased back pain and lower abdominal pain in the experimental group compared to the control group. Conclusion: The study results show that auricular acupressure therapy is effective in improving back pain and lower abdominal pain in female university students during menstruation. Therefore, auricular acupressure therapy can be considered a useful nursing intervention to promote improvements in back pain and lower abdominal pain related to menstruation.

• Research in Community and Public Health Nursing
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• v.6 no.2
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• pp.319-334
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• 1995

To investigate the risk factors of low back pain, an epidemiological study was carried out among male workers aged 20-55 employed in an automobile industry in Korea during the time period from February 1993 to October 1995. Workers participated to this study were divided into low back pain group(LBP) and control group, according to the self-reports by written questionnaires. General characteristics, medical history, work related factors, fatigue, and MMPI were compared between two groups. To clarify the relationship between job related low back pain and radiologic features of lumbar spine, radiographic study was carried out. The resultant data were processed for $x^2-test$, t-test, and stepwise logistic regression to confirm the adjusted odds ratios. The results were as follows: 1. History of back disease, lifting and carrying work, excessive physical fatigue, and weakend back strength of individual workers were directly associated with low back pain. Odd ratios of these 4 risk factors of low back pain were 5.07, 3.34, 1.49, and 1.22 respectively. 2. The frequency of low back pain history was significantly higher in LBP group. 3. Back muscle strength of lumbar spine of LBP group were significantly lower than control group. 4. The workers in LBP group revealed high fatigue symptoms. 5. In MMPI test LBP group showed higher scales in hypochondriasis, depression, hysteria, psychopathic deviate, paranoia, psychasthenia, schizophrenia, and hypomania. 6. LBP group were more frequently involved in lifting and carrying, working in awkward position, bending, twisting and using lower extremities. 7. LBP group were exposed more to vibration during working. 8. In the Analysis of radiographs of lumbar spine, Jacob's line not crossing fourth lumhar disc space, transitional vertebrae and lumbar displacement more than 4.4mm in standing lateral view were more frequently observed in LBP group than control group. Through these results, it is concluded that identification of previous history of back problem, change of work or working environment for workers with previous back problem and measures to relieve both physical and psychological fatigue of the workers are required for optimal management of work-related back problems among workers. In the present study, several results were different from the previous reports: Jacob's line not corssing fourth lumbar disc space, lumbarization, and vertebral slipping (spondylolisthesis) more than 4.4mm are related to backache. Meticulous studies are required to elucidate the difference.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.837-842
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• 2000

In the coiling process of helical steam generator tubes of integral reactor SMART, a considerable amount of spring back, which induces dimensional inaccuracy and difficulty in fabrication, has been arised. In this research, an analytical model was derived to evaluate the amount of the spring back for steam generator tubes. The model was developed on the basis of beam theory and elastic-perfectly plastic material property. This model was extended to consider the effect of plastic hardening and the effect of the tensile force on the spring back phenomena. Parametric studies were performed for various design variables of steam generator tubes in order to minimize the spring back in the design stage. A sensitivity analysis has shown that the low yield strength, the high elastic modulus, the small helix diameter, and the large tube diameter result in a small amount of the spring back. The amount of the spring back can be controlled by the selection of adequate design values in the basic design stage and reduced to an allowable limit by the application of the tensile force to the tube during the coiling process.

• Journal of muscle and joint health
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• v.21 no.3
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• pp.165-172
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• 2014

Purpose: The purpose of this study was to identify effects of postural habits and stress on low back pain experienced by nursing students. Methods: The survey was conducted with 282 students at 5 nursing schools in Seoul, Incheon, Chungcheongbuk, and Jeollabuk Province. Data were collected from October, 2013 to January, 2014. Data analyses including descriptive analysis, ANOVA, Pearson's correlation coefficient, Spearman's rank correlation coefficients, and multiple regression were performed using SPSS 21.0. Results: In multiple regression, habit of standing on force of one feet (${\beta}=.23$, p<.001), habit of sleeping on one's back (${\beta}=-.19$, p=.020), habit of resting the chin on one's hands (${\beta}=.15$, p=.029), and habit of carrying a bag on one shoulder (${\beta}=.12$, p=.011) were associated with low back pain experienced by nursing students. These factors accounted for 12.9% of the variance in the low back pain in undergraduate students. Conclusion: These results suggest that low back pain in nursing students are related to their habits of posture in daily life. Therefore, intervention program to encourage healthy postural habits can be effective to prevent low back pain in nursing students.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.4 s.107
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• pp.324-329
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• 2006

In this paper, a resonator with the substrate integrated waveguide(SIW) structure at the satellite communication band is presented. The SIW structure is realized by via-holes on the dielectric substrate and has an advantage of integration with other circuits. For the measurement, a designed back-to-back transition has the insertion loss of 0.4 dB at 18 GHz. Also, the quality factor of the resonator with the SIW structure including back-to-back transition is obtained to be 222. The high-Q resonator with the SIW structure can be used in filter, oscillator, and voltage controlled oscillator.

• Journal of Magnetics
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• v.15 no.2
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• pp.78-84
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• 2010

A 3-D.O.F. spherical PM motor has 3 degrees of freedom in its motion by tilting and rotating of a shaft, which can be applied in a range of fields. The back-EMF is proportional to the field flux and angular velocity. The back-EMF constant in conventional rotating machine has a uniform value. However, in a spherical PM motor, the back-EMF constant of the coils varies according to the tilting conditions regardless of whether the angular speed is constant. Consideration of the back-EMF constant is useful for designing 3-D.O.F. spherical PM motors. In this study, the back-EMF constant of the spherical PM motor was considered carefully.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.6
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• pp.466-472
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• 2003

This paper describes a tracking control for the mobile robot based on fuzzy systems. Since the mobile robot has the nonholonomic constraints, these constraints should be considered to design a tracking controller for the mobile robot. One of the well-known tracking controllers for the mobile robot is the back-stepping controller. The conventional back-stepping controller includes the dynamics and kinematics of the mobile robot. The conventional back-stepping controller is affected by the derived velocity reference by a kinematic controller. To improve the performance of the conventional back-stepping controller, this paper uses the fuzzy systems known as the nonlinear controller. The new velocity reference for the back-stepping controller is derived through the fuzzy inference. Fuzzy rules are selected for gains of the kinematic controller. The produced velocity reference has properly considered the varying reference trajectories. Simulation results show that the proposed controller is more robust than the conventional back-stepping controller.

• Journal of Mechanical Science and Technology
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• v.14 no.3
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• pp.314-319
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• 2000

Back-face strain compliance (BFS compliance) for the four-point bend specimen has been calibrated for various crack length ratios. Finite element technique was employed to simulate four-point loading and calculate back-face strain of the bend specimen. The numerically determined strain variation along the back face indicates that the sensitivity to gage placement increases with crack length and back-face strain at the gage length less than O.2W, where W is the width of the bend specimen, can be measured within 5% deviation of the maximum BFS. Non-dimensional back-face strain compliance, -E'BCW, was calibrated with FE analysis and experiment. The experimentally determined compliance indicates good agreement with the numerical compliance and can be expressed as a function of crack length ratio.