• 지역사회간호학회지
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• 제14권3호
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• pp.479-487
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• 2003

Purpose: This study was conducted to investigate the progression of Cobb's angle of middle school students according to the Risser grade changes during a one-year follow up period, and to identify the prevalence rate and related factors regarding scoliosis. Method: A total of 2,124 middle school students were preliminarily screened by the Adam's forward bending test. Among them, 21 adolescents diagnosed with scoliosis (above 5Cobb's angle) by X-Raying were the subjects and followed up for checking Cobb's angle and the Risser grade for one year. Results: The overall prevalence of scoliosis in middle school students was 2.13% and the prevalence in girls was higher than in boys. The Cobb's angle was significantly high in seniors and girls. The cases in low angle and low Risser grade demonstrated significant changes in progressive Cobb's angle compared to the cases in high angle and high Risser grade after one-year. But gender and pattern of curvature were not significantly different from the changes scoliosis angle after one-year. Conclusion: Based on these study results, juniors in low Risser grade were inclined to aggravate scoliosis despite the low degree of curvature at the first measurement.

• 대한인간공학회지
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• 제33권3호
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• pp.191-202
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• 2014

Objective: This study is conducted on the differences between flat and curved displays with respect to location of focused points, posture and satisfaction as well as preferred tilt angles. Background: In order to avoid physical and eye fatigue caused by misplayed sitting posture, many studies have asserted that the display requires appropriate location, size and tilt angle as well as curvature. However, most studies have focused on the work environment and the results are varied in the extent. Method: Eye height data in sitting posture were collected from 30 participants. Participants selected the most comfortable viewing angle within the range from $0^{\circ}$ to $12^{\circ}$ while watching videos for both curved and flat display. Then, physical and eye fatigue and overall satisfaction were subjectively evaluated. Lateral diagram describing viewing display condition was set and used to develop linear models for expecting the preferred tilt angle. Results: Due to sitting in the natural viewing posture rather than upright, the eye height is lowered to about 4.6 centimeters, on average, for both displays showing no significant differences. In contrast, preferred angles for the two displays are significantly different and this can be interpreted that curvature vary the points focused. Two linear models as functions of sitting eye height are developed to expect preferred tilt angle for each display. Based on the result of overall satisfaction evaluation, curved display is statistically better than flat display. Conclusion: The results show that flat and curved displays are significantly different expect for the viewing posture. However, reasons for preferring curved display are not accurately factorized and the linear models are limited in the experiment condition such as size of display, distance between display and viewer and other physical environmental factors. Further studies on curved displays under more various conditions are required. Application: This study can contribute to use of the curved display in various way.

• 한국방사선학회논문지
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• 제11권6호
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• pp.467-473
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• 2017

의료용 디지털 영상 및 통신 표준과 3차원 의료 영상 프로그램을 이용하여 외이도의 해부학적 특징들을 비교하였다. 실험은 연령과 성별이 다른 63귀의 영상을 이용하여 외이도의 횡축 길이, 내부 직경 둘레, 상하부 굴곡 각도를 측정한 후 비교하였다. 실험 결과 외이도 형태는 연령과 성별 뿐 만 아니라 동일인의 좌.우 에서도 다르게 나타났다. 성별 비교에서 남자 35귀, 여자 28귀에 대한 평균 길이는 남자가 4.75mm 길게 나타났다. 외이도 직경 둘레는 하부 굴곡 각도를 중심으로 내측이 외측 보다 평균 37.2% 감소된 형태로 나타났다. 상하부 굴곡 각도는 상부가 평균적으로 $25.7^{\circ}$ 높았으나 4귀에서 하부 각도가 높고, 연령이 낮은(4~14세) 8귀에서 상하부 굴곡 각도 차이가 크게 나타났다. 이는 성장하면서 외이도 굴곡 모양이 변화됨을 나타냈다. 본 연구는 기존 귀본 채취를 통한 간접 측정과 물리적 방법에 의한 직접 측정과 비교하여 안전성과 정밀성을 높일 수 있는 방법이다. 이는 3차원 의료 영상 표현 기술이 실제에 가깝게 표현할 수 있는 기술 향상 때문이며 더 발전하여 외이도 형태의 표준화 연구에도 활용될 수 있는 측정 방법이라 판단된다.

• 한국유체기계학회 논문집
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• 제11권1호
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• pp.9-17
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• 2008

A numerical study for three-dimensional laminar flow in the entrance region of helical tubes connected with straight ones is carried out to investigate the effects of Reynolds number, pitch and curvature ratio on the oscillation periods of the flow. The fully elliptic governing equations were solved by means of a finite volume method. The fully developed laminar flow boundary condition was applied at the straight tube inlet. This results cover a curvature ratio range of 1/10${\sim}$1/320, a pitch range of 0.0${\sim}$3.2, and a Reynolds number range of 62.5${\sim}$2000. A comparison is made with previous experimental correlations and numerical data. The developments of velocity, local and average friction factors are discussed. The average friction factors are oscillatory in the entrance region of helical pipes. It has been found that the angle required for the flow to be similarly developed is most affected by the curvature ratio. The pitch and Reynolds number do not have any significant effect on the angle. The characteristic angle ${\phi}_c(={\phi}/sqrt{\delta})$, or the characteristic length to diameter ratio $s_c(=l\sqrt{\delta} cos(atan{\lambda})/d)$, can be useful to represent the development of flow in helical tubes. As the pitch increases and as the curvature ratio and Reynolds number decrease, the amplitude and the number of flow oscillations along the main streamwise direction decrease.

• 한국방재학회 논문집
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• 제7권2호통권25호
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• pp.65-71
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• 2007

본 연구는 만곡하천의 단면을 만곡률에 따라 1 2차원 수치해석을 실시하였다. 수치해석 결과 유 출입각에 따른 수위 편차가 발생하였으며, 홍수량 변동에 따른 편차가 증가하였다. 2차원 수치모형에 의한 수위편차를 보면 유 출입각 105도 일 때 홍수량 500CMS에서 최대경사가 6.67%가 나타났다. 우측은 90도를 초과하는 경우 1차원 수치모형과의 편차가 감소하였으며, 좌측의 수위는 105도를 초과하는 경우 1차원 수치모형과의 편차가 감소하는 것을 확인하였다. 이는 90도 이상의 만곡하천의 경우 수치해석보다는 수리모형실험을 통하여 검증하는 것이 바람직하겠다.

• 대한물리치료과학회지
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• 제5권4호
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• pp.763-775
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• 1998

Some segment or segments of the body must compensate for the heel, and the higher the heel the greater the compensation. Such compensation was once generally thought to take place in the lumbar region and therefore to increase the lumbar lordosis. The purpose of this study is to analyze changes of lumbar sagittal curvature in barefoot and 6cm 12cm high-heel stance. We selected 19 subjects(11 males, 8 females} without history of lower back pain, significant spinal abnormality. And lateral view X-ray of lumbar region from T12 to S1 was taken of each individual. On each X-ray film, lumbar lordotic angle lumbosacral angle and lumbar segmental angles were measured by Cobb method. We drew the following interpretations from the analysis of measured variables of the lumbar region. 1. In comparison of barefoot 6cm heel 12cm heel stance, lumbar lordotic angle had a tendency to decrease according as the heel height was higher. The change in lumbar lordosis measured in high-heel stance was inconsistent with clinical forkelord of hyperlordosis in wearers of high-heeled. 2. Lumbar lordotic angle from T12 to L5 showed sex difference, and was more lordotic in female(p<0.05). 3. There was no sex difference in lumbosacral angle and lumbar segmental angles(p>0.05). 4. There was a significant correlation between lumbar lordotic angle and lumbosacral angle(r>0.60).

• 대한의용생체공학회:의공학회지
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• 제26권6호
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• pp.365-372
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• 2005

Topology optimization method has a great advantage and capability over a conventional shape optimization technique because it optimizes a topology as well as a shape and size of structure. The purpose of the present study, using topology optimization method with an objective function of minimum compliance as a mechanism of bone remodeling, is to examine which shape factors of femur is strongly related with the curvature of femoral shaft. As is expected, the optimized curvature increased definitely with neck angle among the shape factors and showed a similar trend with the measured curvature to neck angle. Therefore, the topology optimization method can be successfully applied in the analysis of bone remodeling phenomenon in the subsequent studies.

• 산업기술연구
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• 제20권A호
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• pp.169-178
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• 2000

The 4-point bending tests have been performed In order to estimate the effect of TIG-dressing on fatigue strength and fatigue characteristics quantitatively for non load-carrying fillet welded joints subjected to pure bending. As a result of fatigue tests, fatigue strengths of as-welded specimens have satisfied the grade of fatigue strength prescribed in specifications of korea, AASHTO and JSSC. Fatigue strength at 2 million cycles of TIG-dressing specimens have increased compared with as-welded specimens. As the result of beachmark tests, fatigue cracks occurred at several points, where the radius of curvature and flank angle in the weld bead toes were low, and grew as semi-elliptical cracks, then approached to fracture. As a result of finite element analysis, stress concentration factor in weld bead toes has closely related to the flank angle and radius of curvature, and between these, the radius of curvature has more largely affected in stress concentration factor than flank angle. As a result of fracture mechanics approaches, the crack correction factor of test specimens has largely affected on stress gradient correction factor in case a/t is below 0.4. From the relations between stress intensity factor range estimated from FEM analysis and fatigue crack growth rate, fatigue life has been correctly calculated.

• 한방재활의학과학회지
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• 제19권2호
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• pp.213-225
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• 2009

Objectives : The purpose of this study was to investigate the factors related on pain in female office workers. Methods : Neck pain group of 31 female subjects complained of neck and arm discomfort. Normal group of 20 female subjects had no complaints or minimal discomfort. Cervical curvature and muscle tone were assessed by whole spine x-ray, meridian-electromyography(MEMG), craniovertebral angle, and Moire. Neck pain was evaluated by Neck Disability Index(NDI) and Visual Analog Scale(VAS). The emotional and other physical factors that could effect neck pain were checked by questionnaires including Beck Depression Index(BDI), Stress Reaction Index(SRI), Holmes & Rahe Social Readjustment Rating Scale(SRRS), International Physical Activity Questionnaire(IPAQ), and Gastrointestinal Symptom Rating Scale(GSRS). Results : The contraction and fatigue of upper trapezius by MEMG was significantly higher in the neck pain group. And BDI, SRI, SRRS, and GSRS were significantly higher in the neck pain group (p<0.05). However, there was no significant difference in the Jackson's angle, Cobb's method, craniovertebral angle, and moire between two groups. Conclusions : The results suggest that neck pain is related to mental stress rather than physical stress and physical stress does not change cervical curvature significantly.

• International Journal of CAD/CAM
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• 제6권1호
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• pp.65-71
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• 2006

Based on the smoothness criterion of minimum curvature variation of the curve, tangent angle constraints guaranteeing an optimized geometric Hermite (OGH) curve both mathematically and geometrically smooth is given, and new methods for constructing composite optimized geometric Hermite (COH) curves are presented in this paper. The comparison of the new methods with Yong and Cheng's methods based on strain energy minimization is included.