• Proceedings of the ESK Conference
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• 1993.04a
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• pp.1-9
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• 1993

A human gait study is required for the biomechanical design of running shoes. A tow-dimensional dynamic model was developed in order to analyze lower extremity kinematics and loadings at the right ankle, knee, and hip joints. The dynamic model consists of three segments, the upper leg, the lower leg, and the foot. Each segment was assumed to be a rigid body with one or two frictionless hinge joints. The lower extremity motion was assumed to be planar in the sagittal plane. A young male subject was involved in the gait test and his anthropometric data were measured for the calculation of segement mass and moment of inertia. The experimental data were obtained from three trials of walking at 1.2m/s. The foot-floor reaction data were measured from a Kistler force plate. The kinematic data were acquired using a three-dimensional motion measurement system (Expert Vision) with six markers, five of which were placed on the right lower extremity segments and the rest one was attached to the force plate. Based on the model and experimental data for the stance phase of the right foot, the calculated vertical forces reached up to 492, 540, and 561 N at the hip, knee, ankle joints, respectively. The flexion-extension moments reached up to 155, 119, and 33 Nm in magnitude at the corresponding joints.

• International journal of advanced smart convergence
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• v.4 no.2
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• pp.163-169
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• 2015

This study proposes a sports simulation device with various harmonics generation. The proposed system is composed of 6 degrees of freedom simulator devices and three types of sports simulation such as walking, snowboard, and jet-ski. In this research, every joint movement is designed with a crank-and-slider mechanism, which is efficient for generating continuous curvature smoothly. Contrary to the conventional spatial simulator with linear actuators, harmonics generation and its spatial combinations become the crucial issue in this research. The harmonic pattern in each joint is modelled for generating smooth curvatures that are also superposed for achieving overall motions. In addition, the targeted motions of sports simulations have different physical factors of periodic gait motion, frictionless surface, and buoyant effects, which are respectively designed by integrating three dimensional graphics information.

• Journal of Electrical Engineering and Technology
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• v.6 no.5
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• pp.618-625
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• 2011

This paper presents a double excited three degree-of-freedom (3DOF) motor. The proposed 3DOF motor is designed with a laminated structure, making it easy to manufacture. In addition, it has windings on the stator and rotor, and does not require an expensive permanent magnet. We explain the structure, principle of motion, and design of the proposed motor, and perform an analysis of the static characteristics using the two- and three-dimensional finite element methods (3D FEM). The feasibility of 3D FEM analysis is confirmed by comparing the 3D FEM analysis and experimental results for the rolling and pitching motion. We also confirm the occurrence of holding torque in every motion.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.9
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• pp.188-195
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• 2004

Severe osteoarthrosis of the knee joint often requires total knee arthroplasty(TKA) to yield adequate knee function. The knee joint with TKA is expected ideally to restore the characteristics, however, this is not necessarily 1.ue in the clinical cases. In this study the motion of the intact joint and the joint after. TKA were investigated numerically using computer simulation. For active knee extension from 90 degrees of flexion to full extension, the intact knee joint exhibited anterior tibial translation near the full extension and it showed only rotation at other flexion angles. Physiologic external rotation of the tibia near full extension known as screw home movement was also noted in the analytical model. The analysis of the tibial insert of three different shapes (flat, semicurved, and curved types) demonstrated characteristic rotational and sliding motion as well as different contact forces.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.507-510
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• 2003

In this paper, optical sensor system using PSD(Position Sensitive Detection) is proposed to obtain the three dimensional position of moving markers attached to human body. To find the coordinates of an moving marrer with stereo vision system, two different sight rays of an moving marker are required. Usually, those are acquired with two optical sensors synchronized at the same time. PSD sensor is used to measure the position of an incidence light in real-time. To get the three-dimension position of light source on moving markers, a conventional camera calibration method are used. In this research, we realized a low cost motion capture system. The proposed system shows high three-dimension measurement accuracy and fast sampling frequency.

• Journal of computational fluids engineering
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• v.20 no.2
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• pp.103-108
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• 2015

Fluid-body interaction analysis of floating body with six degree-of-freedom motion is presented. In this study, three-dimensional incompressible Navier-Stokes equations are employed as a governing equation. The numerical method is based on a finite-volume approach on a cartesian grid together with a fractional-step method. To represent the body motion, the immersed boundary method for direct forcing is employed. In order to simulate the coupled six degree-of-freedom motion, Euler's equations based on rigid body dynamics are utilized. To represent the complex body shape, level-set based algorithm is utilized. In order to describe the free surface motion, the volume of fluid method utilizing the tangent of hyperbola for interface capturing scheme is employed. This study showed three different continuums(air, water and body) are simultaneously simulated by newly developed code. To demonstrate the applicability of the current approach, two different problems(dam-breaking with stationary obstacle and water entry) are simulated and all results are validated.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.6
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• pp.411-414
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• 2018

In this paper, we propose a radar image extraction scheme for frequency modulated continuous wave radar-based human motion indication. We extracted three-dimensional(3D) range-velocity-angle spectra and generated three micro-profile images by compressing the 3D images in all three directions in every frame. Furthermore, we used body echo suppression to make use of the weak reelection such as in hands and arms. By applying the complete images to classifiers, various human motions can be indicated.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.8
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• pp.713-718
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• 2012

Lumber spine range of motion has been used to measure of physical and functional impairment by various tools from a ruler to 3D kinematic devices. However, pre-existing tools have problems in either movement or accuracy and reliability limitations. Accurate devices are limited by fixed space whereas simple devices are limited in measuring complex movements with less accuracy. In order to solve the location, movement and accuracy limitations at once, we have developed a novice measurement device equipped with accelerometer sensor and gyroscope sensor for getting three-dimensional information of motion. Furthermore, Kalman filter was applied to the algorithm to improve accuracy. In addition, RF wireless communication was added for the user to conveniently check measured data in real time. Finally, the measurement method was improved by considering the movement by a reference point. An experiment was conducted to test the accuracy and reliability of the device by conducting a test-retest reliability test. Further modification will be conducted to used the device in various joints range of motion in clinical settings in the future.

• Journal of the Korean Chemical Society
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• v.40 no.6
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• pp.401-408
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• 1996

In general, the high temperature superconductors have two-dimensional anisotropic structures. It is important to investigate the dependence of the critical temperature on the dimensions of the electron's motion. The equation of state for electron gas is deduced which describes the electron's motion in superconductors using the kinetic theory of gas. And the critical temperatures of three, two, and one dimensional gases were calculated. According to these equations, restricting the dimension of the electron's motion induces the increase of the critical temperatures. This implies the possibility that the multi-critical temperature of some superconductors is caused by the change of the dimension related to the pathways of the electron.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.990-1000
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• 2012

In this paper, we propose an algorithm that creates three-dimensional (3D) stereoscopic video from two-dimensional (2D) video encoded by H.264 instead of using two cameras conventionally. Very accurate motion vectors are available in H.264 bit streams because of the availability of a variety of block sizes. 2D/3D conversion algorithm proposed in this paper can create left and right images by using extracted motion information. Image type of a given image is first determined from the extracted motion information and each image type gives a different conversion algorithm. The cut detection has also been performed in order to prevent overlapping of two totally different scenes for left and right images. We show an improved performance of the proposed algorithm through experimental results.