• Journal of Ocean Engineering and Technology
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• v.33 no.5
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• pp.387-393
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• 2019

In this study, the free motion of a riser due to vortex shedding was numerically simulated with Large Eddy Simulation (LES) and Detached Eddy Simulation (DES) turbulence models. A numerical simulation program was developed by applying the Rhie-Chow interpolation method to the pressure correction of the OpenFOAM standard solver pimpleDyMFoam. To verify the developed program, the vortex shedding around the fixed riser at Re = 3900 was calculated, and the results were compared with the existing experimental and numerical data. Moreover, the vortex-induced vibration of a riser supported by a linear spring was numerically simulated while varying the spring constant. The results are compared with published direct numerical simulation (DNS) results. The present calculation results show that the numerical method is appropriate for simulating the vortex-induced motion of a riser, including lock-in phenomena.

• The Journal of Korean Academic Society of Nursing Education
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• v.14 no.1
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• pp.20-29
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• 2008

Purpose: This research was conducted to compare the effects of a muscle strengthening exercise program on pain, straight leg raising ability, passive range of motion, independent walking time and satisfaction with total knee arthroplasty(TKA). Method: A nonequivalent control group posttest only design was used for this study. A total of 62 patients were randomly divided into the experimental group(31) and the control group (31). The experimental group received a 1-hour exercise intervention, while the control group received the usual care. Data was analyzed by t-test using the SPSS/WIN 11.0. Results: The experimental group showed significant improvement in pain score, straight leg raising ability, passive range of motion of knee joint, independent walking time, and the patient's satisfaction. Conclusion: The muscle strengthening exercise program was effective on decreasing pain and increasing mobility and satisfaction in patients with TKA.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1478-1485
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• 2010

In this paper, the nonlinear dynamic response of Vehicle-Bridge interaction with the coupled equations of motion including nonlinear Hertzian contact is presented. The moving train model is chosen to have 10 degrees of freedom (DOF). The bridge is modeled as 2D Euler-Bernoulli beam element with 4 DOF for each element, two for rotations and another two for translations. The nonlinear Hertzian contact is used to simulate the interaction between vehicle and bridge. Base on the relationship of wheel displacement of the vehicle and the vertical displacement of the bridge in Hertzian contact, the coupled equations of motion of the whole system is derived. The convenient formulation was encoded into a computer program. The contact forces, contact area and stress of the rail surface were also computed. The accuracy and efficiency of the proposed program are verified and compared with exact analytical solution and other previous studies. Various numerical examples and parametric studies have demonstrated the versatility and applicability of the proposed program.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.679-684
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• 2000

This paper presents the development of system and program for a Parallel-Typed CNC Machine. The system consists of parallel manipulator, PC (Personal Computer), DMC (DSP Motion Controller), and machining tools. In order to control the manipulator, the program, which is implemented in "c/c++" language, involves inverse/direct kinematics, velocity mapping, Jacobian and etc. A controller computes the kinematic formulation in real-time and generates and motion by the DMC. A monitor, which has access to program and sensory information, displays the status of manipulator.nipulator.

• Structural Engineering and Mechanics
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• v.41 no.6
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• pp.735-750
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• 2012

This paper presents a comparison between two different procedures to deal with the geometric nonlinear analysis of space trusses, considering its structural stability aspects. The first nonlinear formulation, called positional, uses nodal positions rather than nodal displacements to describe the finite elements kinematics. The strains are computed directly from the proposed position concept, using a Cartesian coordinate system fixed in space. The second formulation, called corotational, is based on the explicit separation between rigid body motion and deformed motion. The numerical examples demonstrate the performances and the convergence of the responses for both analyzed formulations. Two numerical examples were compared, including a lattice beam with postcritical behavior. Despite the two completely different approaches to deal with the geometrical nonlinear problem, the results present good agreement.

• Journal of the Korean Applied Science and Technology
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• v.40 no.6
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• pp.1259-1267
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• 2023

The purpose of this study was to investigate the effects of a acute ankle mobility exercise (AE) program on the range of motion and pain levels associated with chronic ankle instability (CAI). Twenty adult women with an average score of 24 or less on both sides in the ankle instability questionnaire were selected and divided into two groups: the Ankle Mobility Exercise Program group (AE, n=10) and the control group (CON, n=10). The AE treatment involved a one-time, 20-minute exercise session for each ankle, conducted separately on the left and right ankles, to examine the response to a acute exercise. Measures of ankle instability, pain, and ankle range of motion were evaluated before and after the treatment. In the AE group, which underwent the AE program, a significant decrease in pain was observed post-AE compared to pre-AE (p<.01). In addition, an increase in dorsiflexion was observed in the AE group post-AE compared to pre-AE following the AE program(p<.05). These results suggest that a acute AE program can effectively alleviate some aspects of ankle instability by improving ankle pain and range of motion in adult women with chronic ankle instability (CAI).

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.6
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• pp.796-802
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• 2018

The effects of inner liquid sloshing on vessel motions are a well-known factor. It was investigated experimentally and numerically. In this regard, the study of many efforts to reduce natural phenomena of vessel motions by adopting special devices especially for roll motions. Among many devices, inserting baffles in the inner liquid tank is very common. In this study, one investigated the vessel motions with inner sloshing tanks with baffles inside. For the numerical simulation, one employed a dynamically coupled program between boundary-element-method-based vessel motion analysis program and a particle-based computational fluid dynamics program. Comparing corresponding experimental results validated the dynamically coupled program. The validated coupled program was used to simulate vessel motions, including sloshing effects with various lengths of inner baffles. The simulation results show that not only the filling ratio of inner liquid, but also the length of clearance due to baffles influenced the vessel motions. The significant point of this study was that the natural frequency of vessel motions can be maintained irrespective of the amount of filling ratio through adjustment of the clearance. In a future study, the effects of various numbers of baffles with various clearances would be conducted to percuss the possibility of vessel motion control with inner liquid sloshing effects.

• Korean Journal of Childcare and Education
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• v.15 no.6
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• pp.139-167
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• 2019

Objective: This study aims to investigate the effects of a learning cycle model-based early childhood education program using physical motion on young children's scientific inquiry ability, scientific attitude, object manipulation ability and spatial ability. Methods: The subjects of this study were 60 five-year-old children who were attending K-G City Childcare Center. The SPSS Window 21.0 program and content analysis method were used, and post-validation Tukey was conducted to examine the differences between the one-way ANOVA and the group. Results: Activities using body movement were practiced systematically based on the circle learning. Children could revise their pre-concept and concept of error by interacting with other children, teachers and the environment. Furthermore, children were attaining new knowledge while they were doing body movement activities, assessing and applying them to actual activities. Conclusion/Implications: This study is investigated a cyclic learning-based early childhood science education program using physical motion, which has significance in systematic and practical early childhood centered education for young children.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.12
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• pp.1252-1257
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• 2009

Off-line 6-DOF simulation program for store separation analysis has been developed. The developed program enables to predict a trajectory of a store from the database which was constructed by wind tunnel testing or CFD analysis. The flow angle method was applied to the program for predicting aerodynamic coefficients from the database and the ejector forces and constraints were enabled to incorporate the equations of motion for computing the trajectory. Using the program, the trajectories were calculated and the results are compared with the CTS results.

• 한국금형공학회:학술대회논문집
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• 2008.06a
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• pp.61-66
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• 2008

The hydraulic system have been used much in a heavy machine which high power source is desired. In the case of the heavy press machine and the injection molding machine, the use of the hydraulic power is essential especially for increasing productivity and getting the good products. Because the hydraulic circuit is very complex and the system parameters are uncertain, the development of the simulation model for hydraulic system is not easy in the heavy machine. In this case, Many researchers have used a commercial program for analysis and development in a major field of study. In this paper, the aim is to develop the simulation model of the hydraulic system with various commercial program for trajectory tracking. And adaptive control method is applied to the simulation model for the trajectory tracking of a cylinder motion. Load on the cylinder is modeled in ADAMS program, the hydraulic circuit including pump, spool valve and cylinder is modeled in AMESim program and a controller is designed in MatLab/simulink program. The suggested model is applied for the tracking of a cylinder motion, and through computer simulation, its trajectory tracking performance is illustrated.