• The KSFM Journal of Fluid Machinery
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• v.16 no.5
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• pp.5-10
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• 2013

The regenerative pump is a kind of turbomachine which is capable of developing high pressure rise at relatively lower flow rates compared to the centrifugal and axial pumps. Although the efficiency of regenerative pumps is much lower than other turbomachines, still they have been widely used in many industrial applications for working at low specific speeds. There are some theoretical models to analysis the pump performance, however, the effect of the blade angle on the pump performance has not been covered in any model to date. In the present study, experimental study on the regenerative pump performance according to the impeller blade angle and its shape has been carried out. The straight radial blades with forward, backward and chevron blades which have inclined angles of $15^{\circ}$, $30^{\circ}$ and $45^{\circ}$ were tested. The pump performance characteristics as the pressure head, efficiency were obtained depending on the flow rate for every impeller, and their results, expressed in appropriate non-dimensional coefficients, were compared and analysed in detail. From the experimental results, it was found that the pressure head and the efficiency depend strongly on the blade angles as well as the blade type. These experimental data has made it possible to better understand the effects of the blade angle on the pump performance, and widen the applicability of the current performance analysis and design models with including the effect of blade angles.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.24 no.1
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• pp.15-21
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• 2018

Background: The purpose of this study was to determine the effects of cervical deep muscle flexion exercise (CCFE) on craniovertebral angle, pain, and neck disability for patients with chronic neck pain Methods: The subjects of this study were randomly divided into three groups of 30 patients with chronic neck pain: rectus abodominis functional massage (n=10), cervical deep muscle flexion exercises group (n=10), and the control group(n=10). To assess visual analog scale (VAS) was used to test the neck pain, To assess neck posture was used to craniovertebral angle, VAS was used to test the neck pain, neck disability index (NDI) was used to test the neck dysfunction. All measurements were performed before and after each intervention was applied 3 times a week for 4 weeks. Results: In the results of all measurements, 2 groups except for the control group showed a significant change in the recovery of posture, neck pain, neck disability index (p<.05). Conclusions: Our results of this study showed that applying cervical deep muscle flexion exercise and rectus abodominis functional massage to patients with chronic neck pain improved cervical posture, neck pain, neck disability.

• Osong Public Health and Research Perspectives
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• v.9 no.6
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• pp.309-313
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• 2018

Objectives: The purpose of this study was to determine whether the cranial vertebral angle (CVA) and the range of motion (ROM) was different between participants with a forward head posture (FHP), with or without pain. Methods: Forty-four participants who had FHP participated in this study. The FHP was assessed digitally by measuring a lateral view the CVA for each subject. A cervical ROM device measured the cervical ROM. The volunteers were allocated to either, with pain (n = 22), or without pain (n = 22) groups, and pain was evaluated using the Numeric Pain Rating Scale. Results: The FHP in the pain group showed a significant difference in the CVA, and the cervical ROM in both flexion and extension, compared with those in the FHP without pain group (p < 0.05). Logistic regression analysis indicated that the occurrence of cervical area pain was higher amongst subjects who had a decreased CVA and flexion motion. Conclusion: This study suggested that decreased CVA and cervical flexion range, were predictive factors for the occurrence of pain in the cervical region.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.01a
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• pp.173-175
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• 2023

최근 좌식생활과 컴퓨터사용의 증가로 전방머리자세 가진 젊은 성인이 증가하고 있으며 이를 개선하기 위한 슬링 뉴렉기법을 적용한 복합운동의 효과를 알아보고자 실시되었다. 이 연구의 결과 운동군에서 통증, 목뼈 앞굽은각, 중력중심선에서 유의한 감소가 나타났다(p<.001). 이러한 결과는 슬링뉴렉을 적용한 복합운동이 억제된 근육에 신경근 활성화와 근육의 재교육을 통해 통증 및 목뼈정렬에 긍정적인 역할을 한 것으로 생각되며 전방두부자세 개선을 위한 효율적인 중재 방법이 될 수 있는 가능성을 확인하였다.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.1
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• pp.107-113
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• 2014

PURPOSE: The purpose of this study was to investigate the correlation between craniovertebral angle (CVA) and cardiorespiratory function ($VO_2max$ and $VCO_2max$) in young adults. METHODS: For this study, the students of D college were questioned and 50 members of D college were participated in our research.. Side-view pictures of each subject were taken in standing positions, in order to assess forward head posture (FHP) by measuring the craniovertebral angle. The craniovertebral angle was measured as the angle between a horizontal line at C7 and a line from the tragus of the ear to the spinous process of C7. And $VO_2max$ and $VCO_2max$ were measured by Quark CPET (cosmed co, USA) while the subjects were performed the treadmill running task of a intensity to set with respiratory mask. Subjucts were Then Pearson's correlation coefficient was calculated to estimate the relationship between craniovertebral and cardiorespiratory function ($VO_2max$ and $VCO_2max$) using SPSS for window. RESULTS: There was a significant positive correlation between craniovertebral angle and $VO_2max$ during treadmill running task (r=0.528, p<0.05). And there was a significant positive correlation between craniovertebral angle and $VO_2max$ during treadmill running task (r=0.566, p<0.05). CONCLUSION: Foreward head posture is related to cardiorespiratory function, and it has a negative correlation with cardiorespiratory function.

• PNF and Movement
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• v.22 no.1
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• pp.1-11
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• 2024

Purpose: The prevalent use of mobile devices may contribute to musculoskeletal disorders, such as forward head posture (FHP), among users. The measurement of the craniovertebral angle (CVA) using photographic images is frequently employed in assessing FHP. Although manual CVA measurement using photographic images is reliable in clinical settings, computer programs or mobile applications to support tele-physical therapy are not yet fully developed. Therefore, in the current study, we propose an automatic method for extracting CVA from photographic images of FHP subjects to facilitate tele-physical therapy. Methods: To develop the automatic CVA measuring computer program, photographic images were obtained from 10 FHP participants. The location information obtained from the markers attached to the tragus and the spinous process of the seventh cervical vertebra were used as coordinates. Using these coordinates, straight line 1 was generated by connecting the seventh spinous process of the cervical vertebra and the tragus, while straight line 2 was drawn parallel to the coordinate obtained from the seventh spinous process of the cervical vertebra. The arc tangent function was used to calculate the angle between the two straight lines. The automatic CVA measurement computer program utilizing photographic images was developed using MATLAB (ver. 2016b). Results: The results showed that the automatic CVA measurement computer program demonstrated stable repeatability and high accuracy. Conclusion: The proposed approach was able to automatically estimate the CVA using photographic images. The developed computer program can potentially be used for easier and more reliable clinical assessment of FHP.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.25 no.1
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• pp.77-81
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• 2019

Background: The Purpose of this study was investigated the effects of the Self Sling Suspension on the numbness, radiated pain, visual analogue scale (VAS), Cobb's angle, Jochumsen's depth, neck disabliity index (NDI). Methods: This study was carried out with a 4 forward head posture (FHP) & 4 herniated nucleus pulposus (HNP) survivors. Outcomes such as the Numbness, Radiated Pain, VAS, Cobb's angle, Jochumsen's depth and NDI were measured pre- and post-intervention for both groups. Results: 2 HNP decrease was found numbness & radiated pain. After the intervention, was decreased VAS, NDI and was increased Cobb's angle, Jochumsen's depth. Conclusions: Applying Self Sling Suspension treatment to FHP & HNP patients proved to have a positive effect.

• The korean journal of orthodontics
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• v.19 no.1 s.27
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• pp.45-59
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• 1989

This study was undertaken to analyze the displacement and stress distribution in the mandible according to the pulling directions during mandibular first molar cervical traction after mandibular second molar extraction. The 3-dimensional finite element method(FEM) was used for a mathematical model composed of 594 elements and 1019 nodes. An orthodontic force, 450 gm, was applied to the each mandibular first molar in parallel, and below the occlusal plane by $7^{\circ}\;and\;25^{\circ}$ and meet the midsagittal plane by $40^{\circ}$ toward posterior direction. The results were as follows: 1. Mandibular teeth were displaced in more downward, posterior and lateral direction. Especially high stress was noted in case of parallel pull than in case of below the occlusal plane by $7^{\circ}\;and\;25^{\circ}$. 2. Mandibular first molar was moved bodily. 3. Generally, alveolar bone, mandibular body, ascending ramus and mandibular angle portion were displaced in downward, posterior and lateral direction. But coronoid process was displaced in downward, forward and lateral direction, and anterior and inner middle portion of condyle head and neck were displaced in downward, forward and medial direction, and posterior and outer middle portion of condyle head and neck were displaced in upward, forward and medial direction. 4. Maximum stress was observed at the condyle head and neck portion. With steeper direction of force, condyle head and neck showed more stress than parallel relation to the occlusal plane.

• The korean journal of orthodontics
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• v.17 no.1
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• pp.55-62
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• 1987

Diagnosis and treatment plans of patients are depended on cephalogram in most case. However, conventional cephalogram may change diagnosis because it ignores a conception of natural head position. The purpose of this study was to investigate the difference of head positions between conventional X-ray taking and x-ray taking in natural head position, and correlation between above results and craniofacial morphology, 60 male students in dental college, Yon sei Univ. were selected, and every cephalogram is studied by comparison of the change of head position. The results are as follows. 1. When taking X-ray by using conventional method, external auditary meatus FH was more tilted than ear rod FM by $2.1^{\circ}{\pm}1.8$ in forward and downward direction. 2. As facial form becomes concave, natural head position and head position, appeared in X-ray taking by using conventional method, become more similiar. 3. Change in head position had showed high correlations with facial form (N-A-Pog angle), and there was high significance to concave group when compared with average group, but significance to convex group was not found. 4. Multiple regression equation concerning change of head position was solved. ${\Delta}FH=24.5\;+\;0.31$ NAPog + 0.43 Prominence of Chin + 0.13 Facial length -0.32 Anterior facial height.

• Journal of Korea Entertainment Industry Association
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• v.14 no.8
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• pp.231-236
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• 2020

The purpose of this study was to investigate the correlation between craniovertebral angle(CVA), age, and body mass index(BMI) in middle-aged people in their 40s and 50s. The forward head posture(FHP) was measured using a posture measuring device using a 3D sensor for 456 healthy men and women. As a result of the study, the middle-aged CVA had a high level of negative correlation with age (r=-.937; p<.01) and a very low level of positive correlation with BMI (r=.071). CVA of middle-aged men had a high negative correlation with age (r=-.932; p<.01) and a very low positive correlation with BMI. There was a correlation (r=.056), whereas, for middle-aged women, there was a high level of negative correlation (r=.939, p<.01) only with age, but had a weak (low level of negative) correlation with BMI. This study suggests that CVA has a significant negative correlation with age in both males and females however, has a weak relationship with BMI.