• Journal of the Society of Naval Architects of Korea
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• v.59 no.3
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• pp.173-182
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• 2022

The present study suggests a procedure of establishing a ship dynamics modeling by regression of free-running model test results. The hydrodynamic force and moment of the whole model ship is derived from the low-pass filtered acceleration in the turning circle and zigzag maneuver tests. Force and moment of the propeller and rudder are separated from that of the whole ship to acquire the hull force and moment terms, based on the principles of the component model. The low-pass filter frequency is verified in prior to dynamics modeling, to find the threshold frequency of 2.5 Hz. The dynamics modeling of the hull is compared with the component modeling by captive model tests. Because of strong correlation between sway velocity, yaw angular velocity, and heel angle, each maneuvering coefficient is not able to be validated, but the whole modeling shows good agreement with the captive model tests.

• Physical Therapy Rehabilitation Science
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• v.12 no.2
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• pp.123-129
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• 2023

Objective: Kinesio tape has been applied to the ankle to improve balance and gait. Stroke patients show abnormal gait patterns due to foot drop. This study aimed to determine the effects of ankle balance taping which to support the ankle joint on balance and gait in patients with chronic stroke. Design: A randomized controlled trial. Methods: Twenty-four chronic stroke patients were selected and randomized into experimental group (n=12) and control group (n=12). The experimental group applied kinesio taping three times a week for three weeks, and the control group applied placebo taping for the same amount of time. To evaluate the effectiveness of the treatment, the subjects' walking ability, static balance, and dynamic balance were assessed before and after the experiment. Gait speed and spatiotemporal gait ability were measured to examine walking ability, postural sway velocity and velocity moment for static balance, and Timed-Up and Go test and Berg Balance Scale were conducted to check dynamic balance. Results: The experimental group showed a significant increase in walking ability, static balance, and dynamic balance in the within-group pre-post difference (p<0.05). In the between-group comparison, the experimental group had a significant difference in walking ability than the control group (p<0.05). Conclusions: Ankle balance taping can help improve gait, and this study can be used as a basis for future studies of ankle balance taping.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.8
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• pp.661-666
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• 2013

A state feedback controller with integration of output error is proposed for way-point tracking of an AUV (Autonomous Underwater Vehicle). For the steering control on the XY plane, the proposed controller uses three state variables (sway velocity, yaw rate, heading angle) and the integral of the steering error, and for the depth control on the XZ plane, it uses four state variables (pitch rate, depth, pitch angle) and the integral of the depth error. From the simulation using Matlab/Simulink, we verify that the performance of the proposed controller is satisfactory within an error range of 1m from the target way-point for arbitrarily chosen sets of consecutive way-points.

• Journal of the Korean Society of Physical Medicine
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• v.8 no.3
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• pp.387-395
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• 2013

PURPOSE: The purpose of the present study was to investigate the effect of the training using Pedalo equipment on balance function in post-stroke patients. METHODS: The present study was case-series. Ten post-stroke patients participated in the study. Participants performed the training using Pedalo equipment. The training using four Pedalo equipment lasted 30 minutes, 3 times a week for 6 weeks. Force platform, Berg Balance Scale(BBS), and Timed Up and Go(TUG) test were used to assess balance ability before and after training. RESULTS: After training using Pedalo equipment, there were significantly improved on path length and sway velocity of post-stroke patients in the both of eye open and - close conditions comparing with baseline. Also, on the BBS and TUG, there were significant improvements after training. CONCLUSION: The results of this study showed that the training using Pedalo equipment may be effective on improving the balance ability in the post-stroke patients. Through this study, we were able to confirm the potential of training using Pedalo equipment as an intervention in the rehabilitation of post-stroke patients.

• Computational Structural Engineering : An International Journal
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• v.2 no.1
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• pp.33-42
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• 2002

A computationally efficient stiffness design method for building structures is proposed in which dynamic soil-structure interaction based on the wave-propagation theory is taken into account. A sway-rocking shear building model with appropriate ground impedances derived from the cone models due to Meek and Wolf (1994) is used as a simplified design model. Two representative models, i.e. a structure on a homogeneous half-space ground and a structure on a soil layer on rigid rock, are considered. Super-structure stiffness satisfying a desired stiffness performance condition are determined via an inverse problem formulation for a prescribed ground-surface response spectrum. It is shown through a simple yet reasonably accurate model that the ground conditions, e.g. homogeneous half-space or soil layer on rigid rock (frequency-dependence of impedance functions), ground properties (shear wave velocity), depth of surface ground, have extensive influence on the super-structure design.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.6
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• pp.445-452
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• 2016

This paper discusses the dynamics and control problem of an overhead shuttle system (OSS), which is a critical part of the automated container terminal at a port. The main purpose of the OSS is efficient automated transport function of containers, which also requires high precision and safety. A major difference between the OSS and the conventional container crane is the configuration of the cables for hoisting the spreader. A mathematical model of the OSS is developed here for the first time, which results in an eight-pole system. Also, open loop control methods (trapezoidal and notch-type velocity profiles) are investigated so that the command input to the overhead shuttle produces the minimum possible sway of the payload. Simulation results show that the vibration suppression capability of the OSS is superior to the conventional overhead container crane, which is partially due to the cable configuration.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1999.10a
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• pp.333-344
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• 1999

Currently many studies on the unmanned gantry crane for the automated container terminal are accomplished. This is needed for the development of large scale, automation, high speed, unmanned system and information system in port facility. In order to do efficient container handling job in port yard, the automated handling system is well adapted to the job environments and all-season weather, In order to realize the automatic and unmanned system for container handling job, the required functions and main structure system are studied. The major problems of operation of the conventional gantry crane are that the vibration of gantry structure body is occurred by operation and that high-speed and precision position-velocity control and the capability to dope to the external disturbances caused by the wind, rain, fog and job environments. In this paper, the fundamental study for establishment of the concept and the dynamic modelling of the major sub system of the unmanned gantry crane is presented. These studies are useful for design and manufacturing of the new concept model of the unmanned gantry crane for efficient operation of the automated container terminal.

• Journal of International Academy of Physical Therapy Research
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• v.11 no.1
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• pp.1950-1953
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• 2020

Background: Ankle instability usually occurs after stroke, and contributes to unsafe walking and associated risk of falling in the affected patients. Objective: To investigate the effects of kinesiology taping (KT) on gait and balance ability (center of pressure, CoP) in patients with ankle instability after stroke. Design: One group, pre-post design. Methods: A total of 11 patients with ankle instability after stroke were enrolled. In all subjects, the gait and balance ability were assessed under 2 conditions: KT and barefoot. Gait and balance ability was assessed using GAITRite system and FDM-S platform. Results: Comparison between KT and barefoot condition, KT condition was significantly higher in velocity, cadence, step length, and stride length than barefoot condition (P<.05). KT condition was significantly lower in CoP path length and sway speed than barefoot condition (P<.05). Conclusion: KT indicated potential as a helpful method for walking and balancing ability in patients with ankle instability after stroke. Therefore, this study recommends KT as an option applicable to the stroke with ankle instability.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.2
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• pp.165-179
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• 2019

Purpose : The purpose of this study is to improve the stroke patient's gait ability by applying a closed or kinetic chain lower limb exercise Methods : The study subjects were 48 hospitalized hemiplegic patients who agreed to participate in the study. 48 subjects went through the intervention: 24 in the experimental group and 24 in the control group. One set consisted of 10 repeats of the exercise. The subjects performed three sets of the exercise once a day, 5 times a week, for 6 weeks. Results : TUG and FGA were significantly improved in the experimental group. The spatio-temporal gait variables in the experimental group all showed significant improvement. In the control group, velocity, cadence, and double limb support showed significant improvement, Trunk sway angle showed significant improvement in all three axes in both groups. Conclusion : The results of this study indicate that a more positive effect in terms of improvement of the stroke patient's gait ability will be seen for closed rather than open kinetic chain lower limb resistance exercise.

• Clinics in Orthopedic Surgery
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• v.10 no.4
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• pp.491-499
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• 2018

Background: Advances in surgical techniques, implant technology, radiotherapy, and chemotherapy have increased the recovery chances of patients with bone sarcomas. Accordingly, patients' expectations on life quality have also increased, highlighting the importance of objective evaluation of the functional results of reconstruction. Methods: Thirteen patients with distal femoral endoprosthesis, who had been followed for an average of 2.9 years were evaluated. Postural stability, daily energy expenditure, muscle power, and range of motion were the four parameters analyzed in this study. The Musculoskeletal Tumor Society (MSTS) score and Toronto Extremity Salvage Score (TESS) were used to assess postoperative function and examine correlations with other parameters. Results: Patients had sedentary activities in 84% of their daily lives. They exhibited a slower speed in the walk across test and a higher sway velocity in the sit-to-stand test (p = 0.005). MSTS scores were significantly correlated with the daily energy expenditure and walking speed. Conclusions: Objective functional results acquired from various clinics will provide significant data to compare reconstruction techniques, rehabilitation protocols, and surgical techniques. In this way, it will be possible to satisfy the expectations of patients that increase in relation to enhanced recovery.