• 한국운동역학회지
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• 제17권4호
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• pp.157-167
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• 2007

The purpose of this study was to analyze kinematic techniques in the woman's 100m hurdle. In order to find the kinematic parameters, a 3-D video system for kinematic analysis-kwon3d 3.1(Kwon3D Motion Analysis Program Version 3.1)-was used. Eight JVC video cameras(GR-HD1KR) were used to film the performance of Lee Yeon-Kyoung at a frame rate of 60fields/s. The kinematic characteristics from the first hurdle to last hurdle were analyzed at the clearing hurdle spots such as distance, velocities, heights and angles. The real-life three-dimensional coordinates of 20 body landmarks during each phases were collected using a Direct Linear Transformation procedure. After analyzing the kinematic variables in the 100m hurdle run, the following conclusion were obtained; Lee Yeon-Kyoung had to maintain constant stride lengths between hurdles and increase takeoff distance before clearance and shorter landing distance after clearance. She also had to hit the correct takeoff point in front of the hurdle and extend the lead leg at the moment of landing in order to minimize the loss of velocity. She had to sprint between hurdles as fast as possible over 8m/s and run powerful first stride and shortened third stride preparing for the following hurdle clearances.

• Journal of Chest Surgery
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• 제12권3호
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• pp.151-158
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• 1979

This is a report of 3 cases of tumors, which primarily originated from ribs and the sternum. In the first case of multiple myeloma, the patient was 67 year old male with a tumor located on the middle sternum invading the manubrium and the body of the sternum manifesting symptoms after a contusion of the anterior sternum. The sternum was entirely resected and was replaced by tantalum plate to reconstruct the defective chest wall in order to prevent the paradoxical movement during respiration. In the second case of osteogenic sarcoma, the patient was 43 year old male with a tumor located on the costochondral junction of the left 5th rib for 6 months. The left 5th rib was resected between the middle part and sternochondral junction of it including tumor and adjacent soft tissues. In the third case of chondrosarcoma, the patient was 36 year old male with a tumor located near the posterior angles of the right 7th and 8th ribs manifesting back pain on the area where the tumor was located. Resection of right lower lobe was performed since direct invasion of tumor was seen in the superior segment of right lower lobe. This was followed by the resection of both 7th and 8th ribs at the area between the costovertebral junction and the portion 10 em apart from the tumor including the tumor and intercostal soft tissues. Diagnoses of 3 cases of tumors described above were confirmed by histopathologic examination postoperatively. The postoperative courses were uneventful.

• Wind and Structures
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• 제31권3호
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• pp.255-267
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• 2020

A systematic set of low-speed wind tunnel experiments was performed at Re = 6.5×10⁴ and 1.1×10⁵ to study the mean wind loading experienced by surface-mounted finite-height square prisms for different aspect ratios, incidence angles, and boundary layer thicknesses. The aspect ratio of the prism was varied from AR = 1 to 11 in small increments and the incidence angle was changed from α = 0° to 45° in increments of 1°. Two different boundary layer thicknesses were used: a thin boundary layer with δ/D = 0.8 and a thick boundary layer with δ/D = 2.0-2.2. The mean drag and lift coefficients were strong functions of AR, α, and δ/D, while the Strouhal number was mostly influenced by α. The critical incidence angle, at which the prism experiences minimum drag, maximum lift, and highest vortex shedding frequency, increased with AR, converged to a value of α_c = 18° ± 2° once AR was sufficiently high, and was relatively insensitive to changes in δ/D. A local maximum value of mean drag coefficient was identified for higher-AR prisms at low α. The overall behaviour of the force coefficients and Strouhal number with AR suggests the possibility of three flow regimes.

• Wind and Structures
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• 제1권3호
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• pp.225-241
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• 1998

The high-rise supporting towers of long-span suspension and cable-stayed bridges commonly comprise a pair of slender prisms of roughly square cross-section with a center-to-centre spacing of from perhaps 2 to 6 widths and connected by one or more cross-ties. The tower columns may have a constant spacing as common for suspension bridges or the spacing may reduce towards the top of the tower. The present paper is concerned with the aerodynamics of such towers and describes an experimental investigation of the overall aerodynamic forces acting on a pair of square cylinders in two-dimensional flow. Wind tunnel pressure measurements were carried out in smooth flow and with a longitudinal intensity of turbulence 0.10. Different angles of attack were considered between $0^{\circ}$ and $90^{\circ}$, and separations between the two columns from twice to 13 times the side width of the column. The mean values of the overall forces proved to be related to the bias introduced in the flow by the interaction between the two cylinders; the overall rms forces are related to the level of coherence between the shedding-induced forces on the two cylinders and to their phase. Plots showing the variation of the force coefficients and Strouhal number as a function of the separation, together with the force coefficients spectra and lift cross-correlation functions are presented in the paper.

• 한국철도학회논문집
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• 제10권4호
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• pp.444-450
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• 2007

The bi-modal tram guided by the magnetic guidance system has two car-bodies and three axles. Each axle of the vehicle has an independent suspension to lower the floor of the car and improve ride quality. The turning radius of the vehicle may increase as a consequence of the long wheel base. Therefore, the vehicle is equipped with the All-Wheel-Steering(AWS) system for safe driving on a curved road. Front and rear axles should be steered in opposite directions, which means a negative mode, to minimize the turning radius. On the other hand, they also should be steered in the same direction, which means a positive mode, for the stopping mode. Moreover, only the front axle is steered for stability of the vehicle upon high-speed driving. In summary, steering angles and directions of the each axle should be changed according to the driving environment and steering mode. This paper proposes an appropriate AWS control algorithm for stable driving of the bi-modal tram. Furthermore, a multi-body model of the vehicle is simulated to verify the suitability of the algorithm. This model can also analyze the different dynamic characteristics between 2WS and AWS.

• 한국운동역학회지
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• 제14권1호
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• pp.1-12
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• 2004

The purpose of this study is to provide training materials for practical use by investigating the kinematical variables of the successful landing by the type of the salto backward such as Tuck, Pike. For this study, the subjects are 4 male national gymnasts using 3-dimensional cinematographic method. Based on the results of this study, the conclusions are drawn as follows. 1. In flight phase, Tuck and Pike show fast extension after completing minimum angle of hip joint passing through the peak. It is very important factor to control body with gaining time before landing while decreasing the velocity of flight rotaion. 2. In Landing phase, the angles of each joint for successful landing are shown as $92deg{\sim}100deg$ for knee angle, $52deg{\sim}57deg$ for hip angle, and $56deg{\sim}70deg$ for shoulder angle. 3. Tuck and Pike dramatically decrease the height of COG, and horizontal/vertical velocity of COG from TD to LD. Also, it is shown that the knee angle, the hip angle and the shoulder angle decrease drastically. On the other hand, the angular velocity of trunk rotation shows negative direction and due to this, the angle of trunk rotation is shown as re-flexion.

• 한국운동역학회지
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• 제29권4호
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• pp.219-226
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• 2019

Objective: The purpose of this study is to provide a better understanding of short turn mechanism by describing short turns after kinematic analysis and provide skiers and winter sports instructors with data through which they are able to analyze right postures for turns in skiing in a systematic, rational and scientific manner. Method: For this, a mean difference of kinematic variables (ski-hip angle, ski-shoulder twist angle, pole checking angle, the center of gravity (CG) displacement, trunk forward lean angle) was verified against a total of 12 skiers (skilled and unskilled, 6 persons each), regarding motions from the up-start to down-end points for short turns. Results: There was no difference in a ski-hip twist angle. The ski-shoulder twist angle was large at the up-start point while a pole-checking angle was high at the down-end point in skilled skiers. Concerning the horizontal displacement of CG, skilled skiers were positioned on the right side at the upstart point. No significant difference was observed in the trunk forward lean angle. Conclusion: According to the ski-shoulder twist angle and CG horizontal displacement results, the upper body should be kept leant toward the pole. In addition, big turns should be made via edging and angulation. During pole checking, the hand holding the pole should be thrown and released toward a vector direction of the forearm.

• 건축역사연구
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• 제4권1호
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• pp.93-112
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• 1995

The wooden pagoda was first appeared in about late 4th century in Korea. And between the late 6th century and the eary 7th centry, the multistoried wooden pagoda was replaced with the stone pagodas, in order to improve their stability and durability. In Three-kingdom and Unificated-Silla period, there are two types of stone stupas in Korea. The one is Paekche(百濟)style, and the other is Silla(新羅) style stone pagoda. These two styles are basically different in each part like podium, roof stone, body stone, structure and the others. Two types of stupas are distributed in two regions which devided into the East(Silla territory) and West(Paekche territory) in the Korean peninsular. The origin of the Korean stone pagoda can be traced to the Paekche dynasty and Silla dynasty. The former were the result of the careful study of their skillful wooden pagodas, where the latter were actualy originated from copying their sundried brick pagodas with stone. Two important pagodas of the primitive stage are the stone pagoda of Miruksa(彌勒寺) temple in Iksan and Bunhwangsa(芬皇寺) temple in Kyungju. These two pagodas are compared with each other in the style of their construction. Silla style have sharp straight lines and short distance between roof stone and eaves. They give us strong as well as intelletural feeling. Howerever, Paekche style has curved lines and dull angles of cutting area of stone, they give us soft feeling.

• 한국군사과학기술학회지
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• 제21권1호
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• pp.10-16
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• 2018

The Republic of Korea Marine Corps is planning to develop a new amphibious assault vehicle which is able to operate with higher water speed than current KAAV. In order to achieve a higher water speed for hydrodynamically bulff-body vehicles, it is essential to develop drag reduction strategies. In this paper, resistance characteristics including trim angles of amphibious assault vehicles with several appendage designs are investigated using a commercial CFD code, STAR-CCM+. The computed results are compared with experimental data conducted at the towing tank with 1:4.5 scaled model and show good correlation. Comparing with the results of bare hull, 3.4 % of hydrodynamic drag and 52 % of trim angle are reduced by the application of double angled bow flap and a hydrofoil attached at the transom.

• 중환자간호학회지
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• 제11권1호
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• pp.79-88
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• 2018

Purpose : This study was performed to evaluate the effects of a prolonged a $30^{\circ}$ side-lying position on comfort and skin condition by applying the trunk maintenance repositioning method, which can keep the $30^{\circ}$ side-lying position effective for preventing pressure ulcers. Method : Fifty-four healthy nurses working at a general hospital in Seoul were randomly assigned to an experimental group (n=27) or a control group (n=27) and assumed a position of lying on their right or left side for two hours. The trunk maintenance repositioning method was applied to the experimental group using the pillow made by the researcher, while the original repositioning method was applied to the control group using the regular pillow from the subject hospital. Participants' posture angles, comfort, and skin condition were measured at the time of the intervention, as well as at one and two hours after the intervention. Results : There was no statistically significant difference in position angle, comfort, skin condition change, or sacrum and greater trochanter pressure change between the two groups over time. Conclusion : It is necessary to review the method and frequency of change of position in each hospital. In addition, a proper position changing pillow should be developed in consideration of patients' various body shapes.