• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.170-178
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• 2004

This paper deals with six degree-of-freedom HILS(hardware-in-the-loop-simulation) of KSR-III rocket using a TAFMS(three axis flight motion simulator). This TAFMS HILS test is accomplished before main HILS tests in order to verify the control stability in the presence of TAFMS dynamic effects. The TAFMS HILS test includes initial attitude holding tests for INS initial alignment procedures, timer synchronization tests with an auxiliary lift-off signal, real-time calibration tests using an external thermal recorder, open-loop TAFMS operating tests, and final closed-loop TAFMS HILS tests using the TAFMS attitude measurements as inputs to the closed control loop. The HILS tests are accomplished for several flight conditions composed with nominal flight condition, TWD effect added condition, slosh modes and/or bending modes existing condition, and windy condition, etc.

• Journal of the Korea Society of Computer and Information
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• v.28 no.5
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• pp.95-102
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• 2023

The purpose of this study was to the effects of the Sling Neurac stabilization exercise(SNSE) on pain, cervical lordosis angle(CLA), and cervical gravity line(CGL) in young adults with a forward head posture. The subjects of the study were selected as SNSEG(n=10) and control group(n=10), they were conducted for 70 minutes three times a week for 8 weeks. Study results showed that pain(p<.001), CGLe(p<.01) were significantly decreased and CLA(p<.001) were also significantly increased in the SNSEG. In conclusion, SNSE is effective in improving the proprioceptive sense of the LM group and activating the muscle. Co-activation with the GM group was found to be effective in improving the CLA and CGL. Therefore, reactivation of the deep neck flexors and suboccipital muscles is an important factor in pain control and postural alignment, and is suggested as an effective intervention method to improve forward head posture.

• Trans-
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• v.4
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• pp.111-134
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• 2018

The purpose of this study is to understand the principles of Balletfit and its program structure and to establish Balletfit's effects on body shape change and postural correction. Interview, the most commonly used method of qualitative research, was chosen as the research method. Ten Balletfit class participants, who have attended private lessons twice per week, for three to six months period of time, were selected. These participants were chosen from participants of private lessons instead of group lessons for in-depth insights. The research was limited to a small group of participants and therefore, it is difficult to standardize the result. Also, because this study is based on the opinions of the participants, not by a posture measuring device, the accuracy of the result is limited as well. The followings are the conclusion of this research. First, the participation motive was either internet research or acquaintance's recommendation. Secondly, the effort to change the body shape. After experiencing Balletfit classes, the participants became aware of their body and made an effort to recover their posture by holding the stomach tight and sitting up correctly. Thirdly, their posture became ideal. Most participants became aware of what an ideal posture is and as their body became ideal, the participants also recovered their health by becoming aware of their inner and outer body. Lastly, they tend to prefer beautiful body line. After the experience, all participants became interested in the body line and preferred to build a beautiful body line with correct postures. The most significant effect of Balletfit was the body line. Therefore, the experience of Balletfit develops the inner and outer body awareness and also can be consider to effect the change of the body shape. Balletfit will become a satisfying exercise for modern people, who desire a beautiful, healthy body.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.224-229
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• 2019

This study was undertaken to provide correct posture guidance and reference material for sports injury and injury prevention programs, by analyzing body alignment and plantar pressure distribution in high school baseball players. Totally, 32 subjects were enrolled for the study. Body alignment was measured from the trunk imbalance, kyphotic angle, lordotic angle, pelvic tilt, and pelvic torsion. Foot pressure was measured from the left maximum pressure, right maximum pressure, left weight, and right weight. The mean and standard deviation of the measured factors were calculated and tabulated, and the correlation between body alignment and foot pressure distribution was analyzed using Pearson's correlation analysis. All statistical significance levels were set at 0.05. Body alignment and foot pressure distribution show a positive correlation between the lordotic angle of lumbar spine and the left maximum pressure. There was no correlation between trunk imbalance, kyphotic angle, lordotic angle, pelvic tilt, pelvic torsion, and the left·right weight distribution and the left·right maximum pressure of each foot. Results of this study determined that the increase of the lordotic angle of lumbar spine results in more force on one side of the foot, thereby increasing the maximum pressure. We believe our data could be a reference for exercise programs on physical alignment and plantar pressure distribution of athletes.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.5
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• pp.1-9
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• 2003

Detailed flow of a shrouded tail rotor in hover is studied by using a compressible inviscid flow solver on unstructured meshes. The numerical method is based on a cell-centered finite-volume discretization and an implicit Gauss-Seidel time integration. Numerical simulation is made for a single blade attached to the center body and guide by the duct by imposing a periodic boundary condition between adjacent rotor blades. The results show that the performance of an isolated rotor without shroud compares well with experiment. In case of a shrouded rotor, correction of the collective pitch angle is made such that the overall performance matches with experiment to account for the uncertainties of the experimental model configuration. Details of the flow field compare well with the experiment confirming the validity of the present method.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.3
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• pp.173-180
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• 2020

Purpose : The aim of this study was to assess the intra- and inter-rater reliability and validity of measurements of head, neck, and pelvis posture using a mobile application in subjects with forward head posture. Methods : Forty-eight volunteers (22 men, 26 women) participated in this study. Two raters independently examined whole body picture images in a lateral standing posture with arms crossed using a CA-Smart Posture Reminder (CA-SPR), and a rater took and calculated posture images twice to assess reliability. We measured five parameters: craniovertebral angle 1 (CVA1), anterior shoulder translation (AST), pelvic tilt (PT), knee angle (KA), and ankle angle (AA) in the subject's sagittal plane using CA-SPR. We examined whole spine X-ray images in the same position to assess validity. We measured four variables in the subjects: CVA2, translation distance (AHT), anterior pelvic plane (APP), and sacral slope (SS). The intra- and inter-rater reliability were calculated using the intraclass correlation coefficient (ICC). Convergent validity was calculated using Pearson's correlation coefficient. Results : The intra-rater reliability (ICC=.889 -.989) and inter-rater reliability (ICC=.800 -.980) were excellent for all variables measured using CA-SPR. The variables measured using CA-SPR and X-ray were significantly positively correlated (r=.623, p<.01). However, the correlation of the variables in the pelvis was not statistically significant. Conclusion : This study shows that a mobile application (CA-SPR) is a useful tool for measuring head and neck posture in subjects with forward head posture. However, further study is needed to measure pelvic variables when using a mobile application.

• Journal of The Korean Society of Integrative Medicine
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• v.12 no.3
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• pp.143-153
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• 2024

Purpose : Forward head posture (FHP), characterized by the anterior positioning of the head relative to the spine, is a common postural deviation that can lead to neck pain, reduced mobility, and muscle imbalances. Recently, high-frequency deep heat therapy (HFDT) has been gaining attention for the intervention of FHP. This research aims to investigate the efficacy of HFDT in comparison to instrument assisted soft-tissue mobilization (IASTM) for treating FHP among 30 young adults. Methods : Participants were randomly assigned to either the HFDT or IASTM group. The study focused on examining changes in neck joint mobility, pain thresholds, rounded shoulder distance, lower trapezius muscle strength, and neck dysfunction. Measurements were taken before and after the interventions. Paired t-tests were used for within-group analyses, and independent t-tests were employed for between-group comparisons. The statistical significance level α was set to .05. Results : Statistically significant improvements were observed across all measured parameters in both groups (p<.05). The HFDT group showed significantly greater enhancements in neck joint mobility, pain thresholds, rounded shoulder distance, lower trapezius muscle strength, and neck dysfunction parameters. Specifically, HFDT was more effective than IASTM in improving neck joint mobility, right upper trapezius pain threshold, left rounded shoulder distance, and right lower trapezius strength. The only exceptions were neck flexion range of motion, left upper trapezius pain threshold, right rounded shoulder distance, and left lower trapezius strength, where no significant differences were found between the groups. Conclusion : The findings suggest that HFDT, by combining the benefits of high-frequency therapy and manual therapy, effectively alleviates upper trapezius muscle pain and tension, enhances neck mobility, and strengthens lower trapezius muscles. Thus, HFDT could be considered a valuable intervention for clinicians aiming to address FHP and associated musculoskeletal problems.

• Journal of Astronomy and Space Sciences
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• v.21 no.4
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• pp.399-416
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• 2004

The FIMS (Far-ultraviolet IMaging Spectrograph), the main payload onboard the first Korean science satellite STSAT-1, has performed various observations since its launch on September 2003. It has been found that the attitude informations provided by spacecraft bus system have a time offset problem, and the problem has been extensively studied. After the time offset correction, boresight offsets between FIMS fields of view, of long and short wavelength bands, respectivley, and spacecraft attitude systems, which are mainly due to alignment error between the FIMS and spacecraft mechanical systems, were calculated through the observations of well known calibration targets. Monthly status and precision of the attitude information are also described. Correction methods for spatially variable exposure, intrinsic to FIMS data, are discussed. These results are essential to the FIMS data analysis, and will be used as references for subsequent studies on more accurate attitude corrections.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.24 no.1
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• pp.1-6
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• 2018

Background: This study was conducted to prove the effects of the Schroth exercise on sagittal postural alignment to the visually impaired students. Methods: The subjects were 8 students who attend the special school in Daegu and performed the Schroth exercise 3 times per week for 3 weeks. Craniovertebral angle and pelvic alignment were measured to compare the effects of the exercise. Results: Craniovertebral angle and pelvic alignment on sagittal plane showed significant differences (p<.05). Conclusions: Schroth exercise was effective to improve postural alignment of sagittal plane to the visually impaired students and these results will have a positive impact on future study of improvement of postural alignment on sagittal plane to the visually impaired students.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.451-454
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• 2006

본 논문에서는 헬기의 인공 시계 시스템용 DGPS/INS 통합 항법 플랫폼을 설계하였다. DGPS/INS 통합 항법 플랫폼 하드웨어는 PowerPC CPU와 Flash ROM과 DDR SDRAM를 이용하여 설계하였다. DGPS 수신기와 IMU와의 연결을 위한 외부 인터페이스부는 직렬 통신을 사용하는 DGPS수신기와 IMU는 모두 사용할 수 있도록 하기 위하여 직렬 통신 방식인 UART 컨트롤러와 SDLC 컨트롤러를 사용하여 설계하였다. 실시간 운영체제를 기반으로 하는 플랫폼의 소프트웨어는 초기 정렬, 자세 계산, 속도 계산, 위치 계산, 통합 필터, 명령 처리 각각에 대하여 태스크로 구성하고 세마포어를 이용하여 태스크간의 동기가 이루어지도록 설계하였다. 통합 항법 플랫폼의 성능 평가를 위하여 차량 실험을 수행하였으며 상용 항법 시스템의 결과와 비교를 하였다.