• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.2
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• pp.263-276
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• 2013

Most yacht sails are made of thin fabric, and they have a cambered shape to generate lift force; however, their shape can be easily deformed by wind pressure. Deformation of the sail shape changes the flow characteristics over the sail, which in turn further deforms the sail shape. Therefore, fluid-structure interaction (FSI) analysis is applied for the precise evaluation or optimization of the sail design. In this study, fluid flow analyses are performed for the main sail of a 30-foot yacht, and the results are applied to loading conditions for structural analyses. By applying the supporting forces from the rig, such as the mast and boom-end outhaul, as boundary conditions for structural analysis, the deformed sail shape is identified. Both the flow analyses and the structural analyses are iteratively carried out for the deformed sail shape. A comparison of the flow characteristics and surface pressures over the deformed sail shape with those over the initial shape shows that a considerable difference exists between the two and that FSI analysis is suitable for application to sail design.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.877-880
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• 2005

This paper suggests gait analysis and gait simulation method using Gait Motion Capture equipment and plantar pressure measurement system. The gait of normal person and how it will be effected by added weight with wearing military equipments are studied by suggested method. It is measured that a change of gait pattern when wears military equipments with Korean male adult(height 180 cm, weight 70 kg) and simulated its results.

• Journal of Korean Neurosurgical Society
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• v.44 no.4
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• pp.240-244
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• 2008

Objective : Sotos Syndrome is characterized by macrocephaly, overgrowth, and developmental delay, and more than 300 patients have been reported worldwide to date. The authors reviewed the clinical characteristics of 8 patients with Sotos Syndrome in Korea for a new understanding and treatment strategies. Methods : The medical records of a total of eight Korean children with Sotos Syndrome were reviewed. All patients underwent developmental checkup, lumbar punctures for measurement of intracranial pressure (ICP), brain and spine magnetic resonance imaging and computerized tomography. Results : All 8 patients showed macrocephaly and the characteristic craniofacial features of Sotos Syndrome. Other clinical characteristics shown were overgrowth (7/8), developmental delay (7/8), congenital heart defect (3/8), flat foot (8/8), scoliosis (4/8), spina bifida (8/8), hydrocephalus (4/8), cavum vergae (3/8), and increased subdural fluid collection (5/8). Mean ICP measured via lumbar puncture was $27.35{\pm}6.25\;cm$ $H_2O$ (range 20 to 36 cm $H_2O$). Two patients received ventriculo-peritoneal shunt, and 1 patient underwent subduro-peritoneal shunt with improvement. Spinal orthosis was applied to 4/5 patients with scoliosis and 4/8 children with flat foot were provided with foot orthosis. Conclusion : In this first Korean study of 8 Sotos Syndrome patients we demonstrated the presence of spina bifida and increased ICP, which had not been previously described. The authors therefore suggest that all patients with Sotos Syndrome should undergo examination for the presence of spina bifida, and that shunt procedures would improve development and alleviate clinical symptoms.

• Korean Journal of Applied Biomechanics
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• v.18 no.3
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• pp.23-31
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• 2008

The purpose of this study was to investigate proper sampling duration while executing quiet stance of feet together position and a preferred foot position with eyes open using COP variables through GRF system. The subjects participated in this study were twenty healthy elderly women individuals($68.9{\pm}6.8$ years). It represented that the sampling duration needed over 20 s in the FTP and over 60 s in the PFP during assessment of quiet stance. The sampling duration shorter than 20 s in the FTP and 60 s in the PFP may not provide the sample showing stability. Inversely if the sampling duration becomes longer, it can distort the sample showing stability. In the future, I expect more studies of the proper sampling duration through various groups and the study of characteristics of participants caused by more sampling duration.

• Journal of Biomedical Engineering Research
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• v.31 no.1
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• pp.50-55
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• 2010

Gait initiation is a transitional process from the balanced upright standing to the beginning of steady-state walking. Dysbalanced gait initiation often causes stroke patients to fall. The net center of pressure, measured by two triaxial force plates from twenty healthy subjects and two stroke patients, was investigated to assess asymmetry of gait initiation in hemiparetic subjects. The time interval and distance of the net center of pressure(CoP) moved from the initiation point to the toe off(S1) and from the toe off to the initial contact(S2) were calculated during gait initiation of normal and stroke patients. When the patient with right hemiplegia(A) initiated his gait with right foot, the time interval and the distance of the net CoP in S1 and S2 were smaller than that of normal subjects' values. However, he initiated the gait with left foot(unaffected side) the time interval and the distance of net CoP in S1 were larger than normative values. Differently, the patient with left hemiplegia(B) has shown that larger time interval and distance in S1 and smaller time interval and distance in S2 in both sides. His asymmetry(with which side the gait initiated) was not significant. It is too early to conclude that these results could be general characteristics of the stroke patients because the variations were large and moreover, the level of motor recovery of the patients was different. However, it is expected that these trials could help to set up the strategy of the therapy for the rehabilitation or prevention of fall in stroke patients.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.2 no.1
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• pp.115-125
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• 2007

Objectives : The limited number of studies to date have mainly focused on the effect of obesity on the characteristics of plantar foot pressures. This study is designed to find the correlation between plantar pressure and obese index. Methods : This study assessed the body composition of 30 obese women using bioelectrical impidence analysis and Gaitview AFA-50. The static and dynamic plantar pressure was determined from electronic footprints captured using a capacitive pressure distribution platform during standing and walking. The data were analysed by independent t-test and Pearson Correlation. Results : Positive correlations were noted between body weight, body mass index(BMI), waist circumference(WC), waist-hip ratio(WHR) and difference of fore and rear plantar pressure. And negative correlations were noted between body weight, BMI, WC, WHR and difference of left and right plantar pressure. Conclusions : The findings of this pilot study suggest that body composition influences the waight distribution in overweight and obese subjects.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.975-976
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• 2010

• Physical Therapy Rehabilitation Science
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• v.9 no.1
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• pp.10-17
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• 2020

Objective: Hallux valgus (HV) is a common musculoskeletal deformity that is accompanied with pain and continues to decrease one's quality of life and ability to perform daily life activities by affecting gait and static stability. Therefore, this study aimed to investigate the effect of the angle of HV (HVA) and to compare the one-legged stance and gait parameters in young adults with less HV and severe HV. Design: Cross-sectional study. Methods: Forty young adults were divided into two groups, where HVA ≥15° (n=20) was defined as HV, and HVA <15° (n=20) was defined as normal. For balance ability, the center of pressure (COP) path, velocity, length of axis of the COP path, deviation of the x-axis and y-axis, and percentage of foot pressure were measured, and gait, the foot rotation angle, step length, percentage of each phase of the gait cycle, time change from the heel to forefoot, and maximum pressure of the forefoot and midfoot were measured. Results: Significant differences were found in sway length and time change from heel to forefoot during walking between the normal and HV groups (p<0.05). Most parameters were not associated with the HVA, but parameters such as length of axis and time to change from heel to forefoot were significantly associated with the HVA (p<0.05). Conclusions: These results suggest that most one-legged stance and gait parameters were not significantly affected by the HVA in young adults; therefore, future studies are needed in order to address other dynamic parameters and other methods of gait analysis for detecting clinically meaningful conditions.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.6 s.171
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• pp.213-221
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• 2005

An insole type local shear force measurement system was developed and local shear stresses in the foot were measured during level walking. The shear force transducer based on the magneto-resistive principle, was a rigid 3-layer circular disc. Sensor calibrations with a specially designed calibration device showed that it provided relatively linear sensor outputs. Shear transducers were mounted on the locations of four metatarsal heads and heel in the insole. Sensor outputs were amplified, decorded in the bluetooth transmission part and then transferred to PC. In order to evaluate the developed system, both shear and plantar pressure measurements, synchronized with the three-dimensional motion analysis system, were performed on twelve young healthy male subjects, walking at their comfortable speeds. The maximum peak pressure during gait was 5.00kPa/B.W at the heel. The time when large local shear stresses were acted correlated well with the time of fast COP movements. The anteroposterior shear was dominant near the COP trajectory, but the mediolateral shear was noted away from the COP trajectory. The vector sum of shear stresses revealed a strong correlation with COP movement velocity. The present study will be helpful to select the material and to design of foot orthoses and orthopedic shoes for diabetic neuropathy or Hansen disease.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.17 no.2
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• pp.131-143
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• 2007

The purpose of this study was to compare the ground reaction forces and plantar pressure variables among three different safety shoes (Type 1: ergonomically designed and high quality shoes, 2: curved and cushioned safety hoes, and 3: regular safety shoes) and to find the effect of insole during walking. Ten healthy subjects were recruited for this study. The ground reaction force was measured using a 3 dimensional motion analysis system. Plantar pressures were measured Pedar Mobile foot pressure scan system. The ground reaction force variables were not significantly different among three different shoe types and insole conditions. After insertion insole, plantar pressure distributions were improved. These results suggest that the type 1 safety shoes was superior than other safety shoes in the statistics, and applying insole could be a possible method to prevent fatigue of lower extremity and musculoskeletal disorders. Further studies are needed to find the effect of ergonomically designed safety shoes design and insole on practical value prevention of musculoskeletal disorder, fatigue and satisfaction of workers.