• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.7 no.6
• /
• pp.110-116
• /
• 1998

For the vibration analysis of 3-dimensional piping system containing fluid flow, a transfer matrix method is presented. The fluid velocity and pressure were considered, that coupled to longitudinal and flexural vibrations. Transfer matrices and point matrices were derived from direct solutions of the differential equations of motion of pipe conveying fluids, and the variations of natural frequency with flow velocity for 3-dimensional piping system were investigated.

• Structural Engineering and Mechanics
• /
• v.69 no.5
• /
• pp.487-497
• /
• 2019

Rapid advances in the engineering applications can bring further areas to provide the opportunity to manipulate anisotropic structures for direct productivity in design of micro/nano-structures. For the first time, magnetic affected wave characteristics of nanosize plates made of anisotropic material is investigated via the three-dimensional bi-Helmholtz nonlocal strain gradient theory. Three small scale parameters are used to predict the size-dependent behavior of the nanoplates more accurately. After owing governing equations of wave motion, an analytical approach based harmonic series is utilized to fine the wave frequency as well as phase velocity. It is observed that the small scale parameters, magnetic field and wave number have considerable influence on the wave characteristics of anisotropic nanoplates. Due to the lack of any study on the mechanics of three-dimensional bi-Helmholtz gradient plates made of anisotropic materials, it is hoped that the present exact model may be used as a benchmark for future works of such nanostructures.

• Therapeutic Science for Rehabilitation
• /
• v.12 no.1
• /
• pp.79-92
• /
• 2023

Objective : This study aimed to assess the reliability of a three-dimensional (3D) motion analysis program for measuring the range of motion (ROM) of wrist and finger joints. Methods : The study recruited 50 people who had no restrictions on wrist and finger movements, understood the purpose of this study, and agreed to participate. Using a goniometer and a 3D motion analysis program, a total of 11 wrist and finger ROM were measured once each. To measure the reliability of the 3D motion analysis program, the degree of agreement and inconsistency of the measured values were compared. Results : Analysis of the degree of agreement of the measured values revealed that 38 out of 44 items showed a very high degree of agreement. Regarding analysis of inconsistency in the measured values, inconsistencies were found in three items. Conclusion : The results of this study confirmed that the ROM of the joint could be measured using the 3D motion analysis program applied in this study. In addition, it might be expected that the 3D motion analysis program would be used in various clinical fields owing to the advantages of measurement convenience and accuracy.

• Journal of Power System Engineering
• /
• v.14 no.2
• /
• pp.48-54
• /
• 2010

An improved numerical scheme, to which the hydroelastic method is adapted, is introduced for predicting the motion and structural responses of tension leg platforms(TLPs) in regular waves. The numerical approach in this work is based on a combination of the three dimensional source distribution method and the finite element method. The hydrodynamic interactions among TLP members, such as columns and pontoons, are included in the motion and structural response analysis. The drag forces on the submerged slender members, which are proportional to the square of relative velocity, are included in order to estimate the responses of members with better accuracy. Comparisons with other results verify the works in this paper.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2003.10a
• /
• pp.444-451
• /
• 2003

In this study, a new three-dimensional finite element analysis model of high-speed railway bridges considering train-bridge interaction, in which various improved finite elements are used for modeling structural members, is proposed. The box-type bridge deck of a railway bridge is modeled by the NFS(Nonconforming Flat Shell) elements with 6 degrees of freedom. Track structures are idealized using the beam finite elements with the offset of beam nodes and those on Winkler foundation with two parameters. And, the vehicle model devised for a high-speed train is employed, which has an articulated bogie system. By Lagrange's equations of motion, the equations of motion of a bridge-train system can be formulated. Finally, by deriving the equations of the forces acting on a bridge considering bridge-train interaction the complete system matrices of total bridge-train system can be constructed. As numerical examples of this study, 2-span PC box-girder bridge is analyzed and results are compared with experimental results.

• Physical Therapy Korea
• /
• v.13 no.2
• /
• pp.61-69
• /
• 2006

The purpose of this study was to compare the electromyography (EMG) activities of the lumbar extensor muscles during motion of trunk flexion-extension and compare range of motion (ROM) with a 3-dimensional motion analysis system of the lumbar region between subjects with chronic low back pain (CLBP) and healthy subjects during the trunk flexion-extension, trunk rotation and trunk lateral flexion cycle. Thirty CLBP subjects and thirty healthy subjects were included. We measured the root mean square (RMS) value of the lumbar extensor muscles from resting, standing, lumbar flexion and return position. The RMS ratio was normalized from maximal EMG activity of the lumbar extensor muscles during trunk motion. The results of this study showed that the RMS ratio of the lumbar extensor was significantly higher in CLBP subjects than healthy subjects during all of trunk motion (p<.05). The ratio of the highest RMS value during flexion and extension was higher in CLBP subjects than in healthy subjects (p<.05). The ROM of the lumbar region was significantly lower in CLBP subjects than healthy subjects during trunk flexion-extension, trunk rotation and lateral flexion cycle. The relationship between the RMS ratio for full lumbar flexion and the ROM of lumbar flexion was not correlated significantly. CLBP subjects have both decreased ROM of the lumbar region and higher muscle activities of the lumbar extensor muscle than healthy subjects.

• Journal of The Korean Society of Integrative Medicine
• /
• v.7 no.2
• /
• pp.59-67
• /
• 2019

Purpose : The purpose of this study was to analyze the dynamic range of motion (ROM) of pelvic and translation of center of mass (COM) when wearing different shoe insole lifts according to leg length discrepancy (LLD) during free speed gait. Methods : Thirty-five healthy adults were participated in this study. Kinematic data were collected using a Vicon motion capture system. Reflective and cluster 40 markers attached to participants lower extremities and were asked to walk in a 6 m gait way under three different shoe lift conditions (without any insole, 1 cm insole, and 2 cm insole). The pelvic ROM and COM translation in three planes were sorted using a Nexus software, and a Visual3D motion analysis software was used to coordinate all kinematic data. Results : There were significantly increased maximal pelvic elevation and total pelvic range in coronal plane when wearing a standard shoe with 2 cm insole lift during gait (p<.05). When wearing a standard shoe with 2 cm insole lift, the total range of the pelvic segment were significantly different in all three motion planes (p<.05). Conclusion : Although LLD of less than 2 cm develops abnormal movement pattern of the pelvis and may cause of musculoskeletal diseases such as low back pain, hip and knee joint osteoarthritis, therefore intensive various physical therapy interventions for LLD are needed.

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

• The Journal of the Korea Contents Association
• /
• v.8 no.2
• /
• pp.91-99
• /
• 2008

When making a comic film, the comic presentation that uses stress and exaggeration is the important subject among other things. In this study we tried to investigate the comic effect using the movement of three-dimensional shot. To conduct this study, we extracted the shot manufactured through the Flow Motion of a 3D Production Program Virtual Camera and a High Speed Motion Picture Camera. The shot manufactured applying this manufacturing skill and using three-dimensional production method for the video contents efficiently made was classified into several scenes. The focus of this study is to search for the factor that makes the atmosphere of a story comic through three-dimensional production shot. According to the shot analysis, three-dimensional production method plays a role in developing more stories on space and time by visualizing stories in three dimensions, which makes the most use of the movement of camera, lens and the utilization of focus. In addition, in the presentation where many comic and exaggerated factors are provided, we used the technology that stresses a scene using the size of a shot and the lasting time and presented the method that exaggerates space using a 3D Production Program Virtual Camera and a High Speed Motion Picture Camera. By reviewing the qualitative improvement and the efficient method on making comic films through the possibility that the atmosphere of this three-dimensional shot can apply to the effect for comic presentation, we tried to approach the comic presentation.

• Korean Journal of Applied Biomechanics
• /
• v.21 no.1
• /
• pp.85-95
• /
• 2011

Three-dimensional(3D) motion analysis is a useful tool for analyzing sports performance. During the last few decades, advances in motion analysis equipment have enabled us to perform more and more complicated biomechanical analyses. Nevertheless, considering the complexity of biomechanical models and the amount of data recorded from the motion analysis system, subsequent processing of these data is required for event-specific motion analysis. The purpose of this study was to develop a basic golf swing analysis algorithm using a state-of-the-art VICON motion analysis system. The algorithm was developed to facilitate golf swing analysis, with special emphasis on 3D motion analysis and high-speed motion capture, which are not easily available from typical video camera systems. Furthermore, the developed algorithm generates golf swing-specific kinematic and kinetic variables that can easily be used by golfers and coaches who do not have advanced biomechanical knowledge. We provide a basic algorithm to convert massive and complicated VICON data to common golf swing-related variables. Future development is necessary for more practical and efficient golf swing analysis.