• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.06a
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• pp.275-276
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• 2013

This analysis method is based on the wave pressure function with the continuity in the analytical region including fluid and porous structures. Wave profiles coming with oblique angle to permeable submerged breakwater on the porous seabed are computed numerically by using boundary element method. When compared with the existing results for the oblique incident wave, the results of this study show good agreement. The results indicate that wave profiles own high dependability regarding the change of oblique incident waves and permeable submerged breakwater on the porous seabed. Therefore, the analysis method of this study are estimated to be applied as an accurate numerical analysis referring to oblique incident waves and permeable submerged breakwater on the porous seabed in real sea environment.

• Physical Therapy Korea
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• v.13 no.3
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• pp.102-110
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• 2006

To improve trunk stability, various exercise protocols were introduced into the clinical field. Trunk and lumbar stability exercises on unstable surfaces are especially recommended to improve lumbar stability. The purpose of this study was to compare abdominal oblique muscle activity during leg raising in hook-lying position among 3 different type of surface conditions (on floor (F), vestibular board (VB), and foam roll (FR)). Sixteen able-bodied volunteers, who had no medical history of lower extremity or lumbar spine disease, were recruited for this study. Surface electromyography (EMG) activity was recorded from the internal and external oblique muscles of both sides. The normalized EMG activity was compared using a one-way repeated ANOVA. The results showed that the EMG activities of the internal oblique and external oblique of the lifted leg side during straight leg raising significantly increased under the FR condition when compared to the F condition. There was no significant difference of the EMG activity in abdominal oblique muscles between the VB and the FR conditions. The EMG activity of the internal oblique of supported leg side during the straight leg raising was significantly greater under the FR condition than the VB and F conditions (p<.05). The composition ratio of EMG activity of internal oblique muscles during straight leg raising was significantly increased under the FR condition. Therefore, straight leg raising exercise on foam roll in hook lying position could be beneficial to improve trunk and lumbar stability.

• The Journal of Korean Physical Therapy
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• v.29 no.3
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• pp.128-134
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• 2017

Purpose: The purpose of this study is to investigate the effects of healthy persons performing a plank exercise with hip abduction and use of sling on trunk muscle activity. Methods: Twenty-three subjects participated in this study. Muscle activities of the multifidus, rectus abdominis, external oblique and internal oblique were assessed with electromyography (EMG) while the subjects performed 6 various types of plank exercises in random order. Results: There was a significant difference in multifidus and internal oblique on the supported side and the multifidus, external oblique, and internal oblique on the elevated side (p<0.05), and differences in plank methods were significantly higher in the multifidus, rectus abdominis, external oblique, internal oblique of the supported side and the rectus abdominis, external oblique and internal oblique on the elevated side (p<0.05). In addition, post-hoc analysis of the various plank methods showed that muscle activity was significantly higher during the general plank exercise compared with the knee-supported-in-sling plank exercises (p<0.05), and was significantly higher with the ankle-supported-in-sling plank exercises compared with the general plank exercise. Conclusion: There was greater trunk muscle activity with plank exercises performed with the ankle-supported-in-sling and hip abduction plank exercises compared with the general or knee-supported-in-sling plank exercises. Through this study, various plank exercises have been discovered that can be selected at different intensities for core muscle training purposes based on trunk muscle strength.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.1
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• pp.159-166
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• 2023

Purpose : The purpose of this study was to compare the differences in muscle activity of the rectus abdominis, internal oblique, and external oblique muscles according to abdominal muscle exercise methods such as plank exercise, side plank exercise, and crunch exercise. Methods : This study was conducted with 37 college students. All subjects participating in this study were randomly assigned to the plank exercise group, the side plank exercise group, and the crunch exercise group. The exercise corresponding to each group was performed for a total of 8 weeks. The muscle activity of the abdominal muscles was measured before the experiment, 4 weeks, and 8 weeks, and the rectus abdominis, internal oblique, and external oblique muscles were measured. Results : As a result of comparison according to the period in the change in muscle activity of the abdominal muscles after exercise, the amount of change in muscle activity in all three muscles showed a significant difference. As a result of the post-hoc analysis, the muscle activity value of the internal oblique muscle after 4 weeks in the plank exercise showed a significant difference from the value after 8 weeks. In the side plank exercise, the muscle activity values of the rectus abdominis and external oblique muscles before and after 4 weeks showed significant differences from those after 8 weeks. And in the crunch exercise, the muscle activity value of the rectus abdominis muscle before exercise showed a significant difference from the value after 8 weeks. Conclusion : Plank exercise increases the muscle activity of the rectus abdominis, side plank exercise increases the rectus abdominis and external oblique muscles, and crunch exercise increases the muscle activity of the rectus abdominis. Therefore, it is thought that the stability of the trunk can be improved more efficiently if all three exercises are performed.

• Journal of International Academy of Physical Therapy Research
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• v.11 no.1
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• pp.1969-1974
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• 2020

Background: Early rehabilitation after partial meniscectomy is important to recover the balance of the vastus medialis oblique and vastus lateralis and prevent pathological problems in the lower extremities and the whole body. Objective: To compare muscle activations for patients after partial meniscectomy. Design: Dual-group Pretest-Posttest Design from the Quasi-Experimental Research. Methods: Twenty participants after partial meniscectomy were recruited and were randomly divided into a Q-setting sensorimotor training group (QSMTG) and Q-setting exercise group (QSEG). Muscle activity of the vastus medialis oblique and vastus lateralis was measured before and after intervention. Results: In the two groups, the vastus medialis oblique and vastus lateralis activations increased significantly (P<.05). The Q-setting sensorimotor training group showed more increases than the Q-setting exercise group, and there were significant differences between the groups (P<.05). The activation ratio of the vastus medialis oblique and vastus lateralis had increasingly significant differences in the Q-setting sensorimotor training group (P<.05), and there were no significant differences between the groups (P>.05). Conclusion: Q-setting exercise with sensorimotor training was a useful method that improved the balance of vastus medialis oblique (VMO) and vastus lateralis (VL) activity after meniscectomy.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.7
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• pp.119-124
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• 1999

A method to find the line of sight ray in space which corresponds to a point in an image plane is presented. The line of sight ray is defined by two points which are the intersections between the two calibration planes and the sight ray. The intersection point is found by the oblique coordinate mapping between the image plane and the calibration plane in the space. The proposed oblique coordinate mapping method has advantages over the transformation matrix method in the required memory space and computation time.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.1
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• pp.56-69
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• 2015

This paper presents a numerical study on investigating on hydrodynamic characteristics of a marine propeller in oblique flow. The study is achieved by RANS simulations on an open source platform - OpenFOAM. A sliding grid approach is applied to compute the rotating motion of the propeller. Total force and moment acting on blades, as well as average force distributions in one revolution on propeller disk, are obtained for 70 cases of combinations of advance ratios and oblique angles. The computed results are compared with available experimental data and discussed.

• Investigative Magnetic Resonance Imaging
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• v.15 no.1
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• pp.11-21
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• 2011

Purpose : Localization using MRI is difficult due to susceptibility induced artifacts caused by metal electrodes. Here we took an advantage of the B0 pattern induced by the metal electrodes by using an oblique-view imaging method. Materials and Methods : Metal electrode models with various diameters and susceptibilities were simulated to understand the aspect of field distortion. We set localization criteria for a turbo spin-echo (TSE) sequence usingconventional ($90^{\circ}$ view) and $45^{\circ}$ oblique-view imaging method through simulation of images with various resolutions and validated the criteria usingphantom images acquired by a 3.0T clinical MRI system. For a gradient-refocused echo (GRE) sequence, which is relatively more sensitive to field inhomogeneity, we used phase images to find the center of electrode. Results : There was least field inhomogeneity along the $45^{\circ}$ line that penetrated the center of the electrode. Therefore, our criteria for the TSE sequence with $45^{\circ}$ oblique-view was coincided regardless of susceptibility. And with $45^{\circ}$ oblique-view angle images, pixel shifts were bidirectional so we can detect the location of electrodes even in low resolution. For the GRE sequence, the $45^{\circ}$ oblique-view anglemethod madethe lines where field polarity changes become coincident to the Cartesian grid so the localization of the center coordinates was more facilitated. Conclusion : We suggested the method for accurate localization of electrode using $45^{\circ}$ oblique-view angle imaging. It is expected to be a novelmethodto monitoring an electrophysiological brain study and brain neurosurgery.

• PNF and Movement
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• v.18 no.1
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• pp.65-75
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• 2020

Purpose: The purpose of this study was to investigate the differences in muscle thickness and ground reaction force of the vastus medialis oblique and vastus lateral oblique muscles during squats at ankle angles of toe 0°, toe in 10°, and toe out 10°. Methods: In this study, 9 male and 17 female students in their 20s participated in a randomized controlled trial and were compared according to the ankle angles of toe 0°, toe in 10°, and toe out 10°. To determine the reliability and measurement of muscle thickness according to ankle angle using ultrasound equipment and muscle thickness, the participants' ankle angles-toe 0°, toe in 10°, and toe out 10°-were measured three times at the vastus medialis oblique and vastus lateralis oblique muscles during squats. At the same time, the maximum vertical ground reaction force was measured with a force plate. A total of three measurements were taken and averaged, and two minutes of squat movements were assessed between ankle angles to prevent target action. Results: The results of this study illustrated that the reliability of the vastus medialis oblique muscles and vastus lateralis oblique muscles in ankle angle was high. The difference in muscle thickness was significantly greater in comparing the toe out 10° angle with the toe 0° angle than between toe in 10° and toe out 10° in vastus medialis oblique and vastus lateralis oblique (p < 0.05). There was no statistically significant difference between the ankle angle of toe 0° and toe in 10° (p > 0.05). The maximum vertical ground reaction force was significantly greater at toe out 10° than at the ankle angle of toe 0° and toe out 10° and between toe in 10° and toe out 10° (p < 0.05). There was no statistically significant difference in the comparison between toe 0° and toe in 10° (p > 0.05). Conclusion: Squatting at an ankle angle of toe out 10° increases the dorsi flexion; thus, the stability of the ankle and the thickness of both oblique muscles increased to perform more effective squats. In addition, as the base of support widens, it is thought that the stability of the posture increases so that squat training can be performed safely.

• Journal of the Korean Society of Radiology
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• v.5 no.4
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• pp.161-169
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• 2011

This research experimented on the change of the multiple colleague scan angle facing one scan object facet to many directions of the form of 3D about the visual angle nervous system forming the cubic distribution with the gradient magnetic field of the mri system and considered the existing basic angle oblique direction test coverage and comparison. MR system can freely select various pulse sequence and image slice. To oblique imaging for optic nerve viewing, we have studied the variation of scan angle between typical oblique scan method (sagittal-coronal plane) and multi directional angles oblique scan method (sagittal-coronal-axial plane) using gradient of MR system. In this study, the subjects of the experiment were normal adults in our country. As a result, we confirmed that multi directional angles oblique scan method can display anatomical information of more wider area than typical oblique scan method. In addition, to clearly display optic nerve, we also confirmed that image slice thickness and pulse sequence have effect on it.