• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.2989-2995
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• 2014

This study was to performed to get the reference data of the kinematic parameters for normal subjects according to the arm movement type. Forty-five normal subjects participated in this study and preformed four sequence according to the arm movement type : normal arm movement, one arm movement, no arm movement, fitness arm movement. The study data was collected from June to August 2010. The kinematic data were measured using Vicon motion system 6MX3 cameras while each subjects walked through a 10m walkway. There were significant differences according arm movement type in the kinematic parameters such as range of motion (ROM) of the right pelvic, hip in sagittal plane, and ROM of the pelvic, hip, lumbar in coronal plane and ROM of the pelvic, thoracic, lumbar in transverse plane. This study can be utilized as the basic reference data in gait analysis for patients with pathologic gaits.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.2
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• pp.236-250
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• 2019

Objectives: The purpose of this study was to investigate the effect of intensive rehabilitation programs on pain, range of motion (ROM), lumbar muscle strength, core muscle endurance, disability, and depression in patients with traumatic low back injuries and to compare the efficacy of this therapy with that of conventional rehabilitation therapy. Methods: The study was performed with a retrospective medical chart review of patients with traumatic low back injury referred to the rehabilitation center at the Daegu Hospital of the Korean Workers Compensation and Welfare Service. Forty-four patients were allocated to either the conventional rehabilitation group (CRG; n = 22) or the intensive rehabilitation group (IRG; n = 22). The CRG group patients, who received 30-min therapist-supervised physical therapy and modality therapy five times per week for four weeks, were compared with the IRG group patients, who received 60-min therapist-supervised physical therapy, 30-min therapist-patient 1:1 matching rehabilitation therapy, and modality therapy five times per week for four weeks. Outcome measures were a numerical rating scale, ROM, lumbar muscle strength, lumbar core muscle endurance, thickness of lumbar deep focal core muscle (transverse abdominis and lumbar multifidus), Oswestry disability index (ODI), and depression (Korean version patient health questionnaire-9). Results: There were statistically significant improvements after treatment in all outcome measures in both groups (p < 0.05). In the intergroup comparison, NRS scores on the activity and thickness of lumbar deep focal core muscles increased significantly more in the IRG than in the CRG (p < 0.05). There were no statistically significant intergroup differences in NRS scores on resting, ROM except left lateral bending, lumbar muscle strength, core muscle endurance, ODI, and depression. Conclusions: We could confirm the superior effectiveness of an intensive rehabilitation program compared to conventional rehabilitation therapy in patients with traumatic low back injuries.

• Structural Engineering and Mechanics
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• v.14 no.5
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• pp.611-624
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• 2002

In this paper, a complete solution is presented for dynamic plastic response of a rigid, perfectly plastic hinged-free beam, of which one end is simply supported or hinged and the other end free, subjected to a transverse strike by a travelling mass at an arbitrary location along its span. The governing differential equations are expressed in non-dimensional forms and solved numerically to obtain the instantaneous deflection of the beam and the plastic dissipated energy in the beam. The dynamic behavior for a hinged-free beam is more complicated than that of a free-free beam. It transpires that the mass ratio and impact position have significant influence on the final deformation. In the aspect of energy dissipation, unlike simply supported or clamped beams for which the plastic deformation consumes almost the total input energy, a considerable portion of the input energy would be transferred as rigid-body motion of hinged-free beam, and the energy dissipated in its plastic deformation is greatly reduced.

• Advances in materials Research
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• v.6 no.1
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• pp.13-26
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• 2017

In this work we introduce a higher-order hyperbolic shear deformation model for bending and frees vibration analysis of functionally graded beams. In this theory and by making a further supposition, the axial displacement accounts for a refined hyperbolic distribution, and the transverse shear stress satisfies the traction-free boundary conditions on the beam boundary surfaces, so no need of any shear correction factors (SCFs). The material properties are continuously varied through the beam thickness by the power-law distribution of the volume fraction of the constituents. Based on the present refined hyperbolic shear deformation beam model, the governing equations of motion are obtained from the Hamilton's principle. Analytical solutions for simply-supported beams are developed to solve the problem. To verify the precision and validity of the present theory some numerical results are compared with the existing ones in the literature and a good agreement is showed.

• Steel and Composite Structures
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• v.24 no.2
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• pp.151-176
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• 2017

This paper deals with general equations of motion for free vibration analysis response of thick three-layer doubly curved sandwich panels (DCSP) under simply supported boundary conditions (BCs) using higher order shear deformation theory. In this model, the face sheets are orthotropic laminated composite that follow the first order shear deformation theory (FSDT) based on Rissners-Mindlin (RM) kinematics field. The core is made of orthotropic material and its in-plane transverse displacements are modeled using the third order of the Taylor's series extension. It provides the potentiality for considering both compressible and incompressible cores. To find these equations and boundary conditions, Hamilton's principle is used. Also, the effect of trapezoidal shape factor for cross-section of curved panel element ($1{\pm}z/R$) is considered. The natural frequency parameters of DCSP are obtained using Galerkin Method. Convergence studies are performed with the appropriate formulas in general form for three-layer sandwich plate, cylindrical and spherical shells (both deep and shallow). The influences of core stiffness, ratio of core to face sheets thickness and radii of curvatures are investigated. Finally, for the first time, an optimum range for the core to face sheet stiffness ratio by considering the existence of in-plane stress which significantly affects the natural frequencies of DCSP are presented.

• Smart Structures and Systems
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• v.22 no.5
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• pp.527-546
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• 2018

This article presents an analysis into the nonlinear forced vibration of a micro cylindrical shell reinforced by carbon nanotubes (CNTs) with considering agglomeration effects. The structure is subjected to magnetic field and transverse harmonic mechanical load. Mindlin theory is employed to model the structure and the strain gradient theory (SGT) is also used to capture the size effect. Mori-Tanaka approach is used to estimate the equivalent material properties of the nanocomposite cylindrical shell and consider the CNTs agglomeration effect. The motion equations are derived using Hamilton's principle and the differential quadrature method (DQM) is employed to solve them for obtaining nonlinear frequency response of the cylindrical shells. The effect of different parameters including magnetic field, CNTs volume percent and agglomeration effect, boundary conditions, size effect and length to thickness ratio on the nonlinear forced vibrational characteristic of the of the system is studied. Numerical results indicate that by enhancing the CNTs volume percent, the amplitude of system decreases while considering the CNTs agglomeration effect has an inverse effect.

• Clinics in Shoulder and Elbow
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• v.5 no.2
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• pp.102-109
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• 2002

Purpose: To evaluate the results of the treatment of the supracondylar fractures of the humerus according to the fixation methods in adults Materials and Methods: Seven patients, aged 55 to 52 years (average,69 years), were reviewed after a mean follow-up of 37 months (range, 11-65 months). According to AO classification all fractures were classified as type A2 (simple transverse supracondylar fracture). Six patients underwent closed reduction and one patient, open reduction after failure of closed reduction. Percutaneous fixation with cannulated screws was performed to the 4 patients, per- cuta)leous fixation with Kirschner wires in 3 patients. All except one patients have associated medical problems. The results were assessed based on the Mayo Elbow Performance Score. Results: All the patients with cannulated screw fixation had stable bony union with excellent ranges of motion (mean: 5-125 degrees). All the three patients who received percuatnaous smooth K-wire fixation had nonunion with poor results, one of them had changed into cannulated screw. and then had good result. Conclusion: Although simple supracondylar fracture is similar to the pediatric fracture in nature, it should be firmly fixed with the method such as threaded cannualted screw rather than the simple fixation with K-wires.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.221-226
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• 2005

In this paper, a dynamic model for the rotor shaft-coupling-blade system is developed. The blades are attached to a disk and driven by an electric motor shaft which is flexible in torsion. We assumed that the shaft torsional flexibility is lumped in the flexible coupling which is usually adopted in rotor systems. The Lagrangian approach with the small deformation theory for both blade-bending and shaft-torsional deformations is employed for developing the equation of the motion. The assumed modes method is used for estimating the blade transverse deflection. The numerical results highlight the effects of both structural damping of the system and the torsional stiffness of the flexible coupling to the dynamic response of the blade. The results showed strong coupling between the blade bending and shaft torsional vibrations in the form of inertial nonlinearif, stiffness hardening and softening.

• Journal of the Korea Computer Industry Society
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• v.6 no.2
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• pp.331-336
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• 2005

The closed movement produced vertically on the position of a motor is a notation movement produced by a notation force , while the horizontal movement can be shown by the coriolis force and the transverse force of realizing that the closed movement of the closed system is to be rotation motion. The notation movement is a vertical closed movement and by searching the equation which becomes an equation model, after comparing the simulation data from the equation model with data of a real device to use it into the computer simulation model, the additional variable elements were decided. As the result, the energy imbalance element is added as a variable about load which is relevant to friction coefficient and pole of a motor in the gravitational field. The simulation can be applied as a real physical law of the graphic game and haptic program.

• Journal of Ocean Engineering and Technology
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• v.17 no.2
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• pp.72-76
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• 2003

This paper presents the design concept and operation results of float-off for FSO (340,000 DWT Class, ELF AMENAM KPONO Project) built on the ground, without dry dock facilities. It was the first attempt to build FSO, completely, on the ground and launch it using DBU (Double Barge Unit, which was connected by rigid frame structure.) The major characteristics of FSO, which are similar to general VLCC type hull, including topside structure, weigh 51,000 metric ton. In order to have sufficient stability during the deck immersion of DBU, while passing through a minimum water plane area zone, proper trim control was completed with LMC (Load Master Computer). The major features of the monitoring system include calculation for transverse bending moment, shear force, local strength check of each connector, based on component stress, and deformation check during the load-out and float-off. Another major concern during the operation was to avoid damages at the bottom and sides of FSO, due to motion & movement after free-floating; therefore, adequate clearances between DBU and FSO were to be provided, and guide posts were installed to prevent side damage of the DBU casings. This paper also presents various measures that indecate the connector bending moment, damage stability analysis, and mooring of DBU during float off.