• 한국항해항만학회지
• /
• 제37권4호
• /
• pp.345-350
• /
• 2013

제한수역에서 측벽부근을 대형선박이 항행할 경우, 측벽으로 인하여 발생하는 유체력이 대형선박의 조종운동에 상당히 크게 영향을 미친다는 것은 잘 알려져 있다. 이 논문에서는 방파제형상을 하고 있는 측벽 부근을 대형선박이 항행하는 경우, 선박과 방파제 형상간의 간섭력 추정을 위해 세장체 이론을 토대로 한 계산 방법을 적용하였으며, 선박에 미치는 측벽의 영향을 파악하기 위하여 방파제길이, 방파제와 선박간의 거리 및 수심을 변수로 하여 선박과 측벽과의 간섭력을 수치 계산하였다.

• Journal of Ship and Ocean Technology
• /
• 제8권3호
• /
• pp.26-39
• /
• 2004

A vessel/mooring/riser coupled dynamic analysis program in time domain is developed for the global motion simulation of a turret-moored, tanker based FPSO designed for 6000-ft water depth. The vessel global motions and mooring tension are simulated for the non-parallel wind-wave-current 100-year hurricane condition in the Gulf of Mexico. The wind and current forces and moments are estimated from the OCIMF empirical data base for the given loading condition. The numerical results are compared with the OTRC(Offshore Technology Research Center: Model Basin for Offshore Platforms in Texas A&M University) 1:60 model-testing results with truncated mooring system. The system's stiffness and line tension as well as natural periods and damping obtained from the OTRC measurement are checked through numerically simulated static-offset and free-decay tests. The global vessel motion simulations in the hurricane condition were conducted by varying lateral and longitudinal hull drag coefficients, different mooring and riser set up, and wind-exposed areas to better understand the sensitivity of the FPSO responses against empirical parameters. It is particularly stressed that the dynamic mooring tension can be greatly underestimated when truncated mooring system is used.

• PNF and Movement
• /
• 제20권1호
• /
• pp.59-66
• /
• 2022

Purpose: The aim of this research was to verify the relationship between three-dimensional (3D) ground reaction force (GRF) and severity of leg length discrepancy (LLD) while walking at a normal speed. It used a 3D motion analysis system with force platforms in standing workers with LLD. Methods: Subjects comprising 45 standing workers with LLD were selected. Two force platforms were used to acquire 3D GRF data based on a motion analysis system during gait. Vicon Nexus and Visual3D v6 Professional software were used to analyze kinetic GRF data. The subjects were asked to walk on a walkway with 40 infrared reflective markers attached to their lower extremities to collect 3D GRF data. Results: The results indicated the maximal force in the posterior and lateral direction of the long limb occurring in the early stance phase during gait had significant positive correlation with LLD severity (r = 0.664~0.738, p <0.01). In addition, the maximal force medial direction of the long limb occurring in the late stance phase showed a highly positive correlation with the LLD measurement (r = 0.527, p <0.01). Conclusion: Our results indicate that greater measured LLD severity results in more plantar pressure occurring in the foot area during heel contact to loading response of the stance phase and the stance push-off period during gait.

• 한국의학물리학회지:의학물리
• /
• 제15권1호
• /
• pp.30-38
• /
• 2004

목적: 방사선 치료 시 환자의 움직임을 최대한 고정시켜 줄 수 있으며 환자 자세에 대한 Setup 오차를 감소시키고 환자 전신에 산재한 병소를 위치화하고 좌표화할 수 있는 전신 정위 고정장치 제작과 제작한 고정장치에 대한 고정효과 및 재현성을 나타내는 환자 자세의 Setup 오차를 평가하였다. 대상 및 방법: 자체 제작한 고정장치는 크게 기본판(base plate)과 고정틀(Immobilizer), Vacuum cushion, 벨트로 이루어진다. 기본판은 50${\times}$130${\times}$1 ㎤ 베크라이트로 고정틀은 견고한 아세탈 재질을 사용하여 제작하였다. 초기의 Lax frame의 경우, side panel에 부착되어 있는 좌표계(coordinates)를 기본판 바닥에 radiopaque catheter wire를 사용하여 N 타입으로 새겨서 넣어 위치측정이 가능한 좌표계로 적용할 수 있도록 하였다. 제작된 고정장치에 대한 성능실험으로 방사선 투과율 측정 실험과 가상표적을 부착한 지원 환자를 대상으로 표적에 대한 위치측정실험이 수행되었다. 그리고 CCTV 카메라와 Digital Video Recorder (DVR)를 이용하여 획득된 환자 영상을 Matlab 프로그램으로 환자 자세에 대한 Setup 오차를 분석하였다. 결과: 전신 정위 고정장치는 CT 촬영과 방사선치료 시 사용 가능성에 중점을 두고 제작되었다. 이 고정장치의 구조는 갠트리의 회전각의 변화에 따라 충돌하지 않게 제작되었고 측면으로 경사지게 입사되는 빔의 투과율을 최대화할 수 있게 제작되었다. 고정틀의 고정효과를 높여주는 고정벨트는 입사된 빔의 방향에 방해되지 않게 제작되었다. 고정장치에 대한 방사선 투과율은 10과 21 MV의 에너지에서 95, 95%로 측정되었고 지원 환자에 부착한 가상 표적의 위치는 CT 촬영으로 파악할 수 있었다. Matlab 프로그램으로 분석한 setup 오차는 흉부의 측면과 중심부위에서 3.69$\pm$1.60, 2.14$\pm$0.78 mm이고 복부의 측면과 중심부위에서 7.11$\pm$2.10, 6.54$\pm$2.22 mm이며 여자 환자 경우, 가슴 측면의 Setup 오차는 6.33$\pm$1.55 mm으로 측정되었다. 결론: 전신 정위 고정장치의 제작과 실험을 통해 extra-cranial 암에 대한 방사선수술에서 매우 실용적이고 유용하게 사용될 것으로 사료되며 표적 위치 결정과 환자 고정 도구로서 사용될 것이다. 더 많은 환자 치료자세의 Setup 오차 측정이 수행되면 정확한 환자의 Setup 오차의 결과를 향상시킬 수 있을 것으로 기대된다.

• 대한조선학회논문집
• /
• 제29권3호
• /
• pp.45-52
• /
• 1992

조종운동(操縱運動)의 정확(正確)한 예측(豫測)이 절실(切實)하게 요구되는 항만내(港灣內)에서의 조종운동(操縱運動)과 같이, 저속(低速)이며 또 천수역(淺水域)에서의 선박(船舶)의 조종운동(操縱運動)을 잘 표현(表現)하는 수학(數學) Model은 아직 얻어지지 않고 있는 것이 현재까지의 실정(實情)이라 할 것이다. 일본의 Kose는 저속시(低速時) 선체유체력(船體流體力)의 새로운 Model을 제안(提案)한 바 있으나 아직 그 유용성에 대해서는 다방면(多方面)에서 검토(檢討)가 필요(必要)하다고 할 것이다. 본(本) 논문(論文)은 이러한 현실(現實)에서, 우선 저속시(低速時)의 Hull 유체력(流體力)을 잘 표현(表現)할 수 있는 새로운 방법(方法)을 모색하여 이를 Kose의 Model이나 종래(從來)의 M.M.G.Model 또는 Cross-Flow Drag Model등과 비교하여, 저속시(低速時)의 선체(船體)에 작용(作用)하는 유체력(流體力)을 잘 나타낼 수 있는 Model을 개발하려고 한다. 수학(數學) Model의 우열(優劣)을 판정하는 방법으로서는, 일본의 RR-742부회(部會)에서 실험한 저속시(低速時)($f_n={\pm}0.06,\;U={\pm}0.3m/s$)의 전후진(前後進)에 대한 Bare Hull의 CMT결과로 얻어진 전후력, 횡력, 선회모멘트를 Data로 삼아 이들을 각각 Kose Model, Cross-flow Model, MMG Model 및 신(新) Model에 의하여 Fitting하고, Fitting의 표준편차(標準偏差)를 비교하였다.

• 한국운동역학회지
• /
• 제33권1호
• /
• pp.25-33
• /
• 2023

Objective: The purpose of this study was to investigate the differences in static arch height and ankle stability according to the preference for insole height and hardness in the arch area. Method: The study participants were 20 adult males (age: 22.7 ± 1.8 yrs., height: 175.3 ± 4.3 cm, body weight: 72.5 ± 7.7 kg). First, the arch heights of all subjects were measured in static postures (sitting and standing). The inversion and eversion movements of the ankle joint were analyzed during walking (1.3 m/s & 1.7 m/s) and running (2.7 m/s & 3.3 m/s). The variables (static arch height, and inversion and eversion angle of ankle joint) were compared by classifying groups according to the preference for the height and hardness of the arch of the insole. First, it was divided into a high arch insole preference group (HAG, n=8) and a low arch insole preference group (LAG, n=12) according to the preference for the arch height of the insole. Second, it was divided into a high hardness insole preference group (HHG, n=7), medium hardness insole preference group (MHG, n=7), and low hardness insole preference group (LHG, n=6), according to the preference for the arch hardness of the insole. Results: First, the range of motion (ROM) of inversion-eversion at the ankle joint during walking was statistically smaller in HAG than in LAG (p<.05). Second, the arch height change of HHG was statistically greater than that of MHG and LHG (p<.05). Conclusion: In the case of flexible flat feet with a large change in arch height, providing a high hardness arch insole that can disperse foot pressure can improve comfort. It was found that people with high medial and lateral sway of the ankle joint preferred a low arch insole, but it is necessary to differentiate and compare the insole heights of the arch part in detail. In addition, in the case of fast motion such as running, the preference for the arch height and hardness of the insole was not related to the static arch height and ankle stability.

• Journal of Korean Neurosurgical Society
• /
• 제61권2호
• /
• pp.243-250
• /
• 2018

Objective : To compare the morphometry of subaxial cervical spine between cerebral palsy (CP) and normal control. Methods : We retrospectively analyzed 72 patients with CP, as well as 72 patients from normal population. The two groups were matched for age, sex, and body mass index. Pedicle, lateral mass (LM), and vertebral foramen were evaluated using computed tomography (CT) imaging. Pedicle diameter, LM height, thickness, width and vertebral foramen asymmetry (VFA) were measured and compared between the two groups. Cervical dynamic motion, disc and facet joint degeneration were investigated. Additionally, we compared the morphology of LM between convex side and concave side with cervical scoliotic CP patients. Results : LM height was smaller in CP group. LM thickness and width were larger in CP group at mid-cervical level. In 40 CP patients with cervical scoliosis, there were no height and width differences between convex and concave side. Pedicle outer diameter was not statistically different between two groups. Pedicle inner diameter was significantly smaller in CP group. Pedicle sclerosis was more frequent in CP patients. VFA was larger in CP group at C3, C4, and C5. Disc/facet degeneration grade was higher in the CP group. Cervical motion of CP group was smaller than those of the control group. Conclusion : LM morphology of CP patients was different from normal population. Sclerotic pedicles and vertebral foramen asymmetry were more commonly identified in CP patients. CP patients were more likely to demonstrate progressive disc/facet degeneration. This data may provide useful information on cervical posterior instrumentation in CP patients.

• Earthquakes and Structures
• /
• 제10권2호
• /
• pp.329-350
• /
• 2016

A parametric study was conducted to investigate the seismic deformation demands in terms of drift ratio, plastic base rotation and compression strain on rectangular wall members in frame-wall systems. The wall index defined as ratio of total wall area to the floor plan area was kept as variable in frame-wall models and its relation with the seismic demand at the base of the wall was investigated. The wall indexes of analyzed models are in the range of 0.2-2%. 4, 8 and 12-story frame-wall models were created. The seismic behavior of frame-wall models were calculated using nonlinear time-history analysis and design spectrum matched ground motion set. Analyses results revealed that the increased wall index led to significant reduction in the top and inter-story displacement demands especially for 4-story models. The calculated average inter-story drift decreased from 1.5% to 0.5% for 4-story models. The average drift ratio in 8- and 12-story models has changed from approximately 1.5% to 0.75%. As the wall index increases, the dispersion in the calculated drifts due to ground motion variability decreased considerably. This is mainly due to increase in the lateral stiffness of models that leads their fundamental period of vibration to fall into zone of the response spectra that has smaller dispersion for scaled ground motion data set. When walls were assessed according to plastic rotation limits defined in ASCE/SEI 41, it was seen that the walls in frame-wall systems with low wall index in the range of 0.2-0.6% could seldom survive the design earthquake without major damage. Concrete compressive strains calculated in all frame-wall structures were much higher than the limit allowed for design, ${\varepsilon}_c$=0.0035, so confinement is required at the boundaries. For rectangular walls above the wall index value of 1.0% nearly all walls assure at least life safety (LS) performance criteria. It is proposed that in the design of dual systems where frames and walls are connected by link and transverse beams, the minimum value of wall index should be greater than 0.6%, in order to prevent excessive damage to wall members.

• 대한물리의학회지
• /
• 제12권4호
• /
• pp.133-138
• /
• 2017

PURPOSE: The purpose of this study was to investigate the effect of modified motor developmental intervention on the SCM muscle thickness and the range of motion (ROM) of neck in subjects with congenital muscular torticollis. METHODS: Thirteen subjects who had congenital muscular torticollis were participated in this study and they were offered the modified motor developmental interventions for 8 weeks by pediatric physical therapist. SCM thickness of affected and non-affected side and ROM of neck rotation were collected between before and after intervention. SCM thickness was measured by using Ultrasound Unit (IU 22, Ultrasound system, Philips, Netherlands) and ROM of neck was measured by using the goniometer (Arthrodial protractor, North coast, USA). Data were represented as means ${\pm}SD$. Paired t-test was used to determine the effect of interventions on the SCM muscle thickness and neck ROM. RESULTS: SCM thickness of affected side was significantly decreased after the modified motor developmental interventions and that of non-affected side was generally increased but it was not significantly difference between pre and post interventions. ROM of neck rotation and lateral flexion was significantly increased after interventions. CONCLUSION: These results suggested that the modified motor developmental interventions could improve the recovery of SCM muscle thickness and neck ROM.

• 대한족부족관절학회지
• /
• 제3권1호
• /
• pp.19-25
• /
• 1999

The purpose of this study Is to assess the retained range of motion[RROM] of the foot after arthrodesis of the ankle joint, which might help designing the angle of arthrodesis. We reviewed the results including the RROM in 14 cases of ankle arthrodesis. Underlying causes included trauma group(six posttraumatic arthritis) and disease group(three osteoarthritis, three Charcot joints, one chronic synovitis and one pyogenic arthritis). We measured the RROM on the lateral roentgenograms of the ankle in full dorsiflexion and plantarflexion, The results were assessed by the AOFAS hindfoot scale[score]. The RROM in sagittal plane was $23.4{\pm}5.3$ degrees and the score was 71.5 points on average. The RROM and the score were $26.8^{\circ}{\pm}2.1$, 81.2 points respectively in trauma group and $20.8^{\circ}{\pm}5.6$, 64.3 points in disease group; $26.6^{\circ}{\pm}2.3$, 83.4 points in cases younger than 40 years of age and $21.6^{\circ}{\pm}5.7$, 64.9 points in the older. The mean score was 77.3 points in cases whose RROM were $24^{\circ}$ or more and 61 points in cases of less RROM; 69.6 and 73.4 points in cases with and without adjacent degenerative arthritis respectively. The score was 69.7, 73.3 and 71.5 points in cases whose angle of arthrodesis was in dorsiflexion, neutral, plantarflexion respectively. In conclusion, after ankle arthrodesis RROM of the foot was $23.4^{\circ}$, and the more the RROM, the higher the score. In cases with sufficient amount of RROM, the angle of fusion on sagittal plane might not influence the result significantly.