• Interaction and multiscale mechanics
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• v.6 no.4
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• pp.339-356
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• 2013

This paper investigates the optimized parameters of Tuned Mass Dampers (TMDs) for vibration control of high-rise structures including Soil Structure Interaction (SSI). The Artificial Bee Colony (ABC) method is employed for optimization. The TMD Mass, damping coefficient and spring stiffness are assumed as the design variables of the controller; and the objective is set as the reduction of both the maximum displacement and acceleration of the building. The time domain analysis based on Newmark method is employed to obtain the displacement, velocity and acceleration of different stories and TMD in response to 6 types of far field earthquakes. The optimized mass, frequency and damping ratio are then formulated for different soil types; and employed for the design of TMD for the 40 and 15 story buildings and 10 different earthquakes, and well results are achieved. This study leads the researchers to the better understanding and designing of TMDs as passive controllers for the mitigation of earthquake oscillations.

• ETRI Journal
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• v.25 no.2
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• pp.133-139
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• 2003

We studied how the passive intermodulation (PIM) power arising in air cavity filters could be calculated and how the design of the filter could be optimized in order to reduce the amplitude of the PIM signal. To do this, using simulated results, we optimized the various parameters of a filter. PIM in an air cavity filter depends on the power dissipated in its cavities. A reduction of this power loss therefore decreases the PIM power in the air cavity filter. Our experimental results confirm that it is possible to design and produce air cavity filters that generate low PIM signals.

• Journal of Auto-vehicle Safety Association
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• v.10 no.2
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• pp.6-12
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• 2018

Optimized section shape of aluminum bumper backbeam for enhancing the front high speed crashworthiness was investigated. Front body analysis model of a convertible vehicle was built up and parameter studies were carried out with changing the inner rib shape and the section thickness distribution. First an inner rib shape displaying most efficient structural performance was selected. Next, for the selected section the effect of section thickness combination was examined. Also, a light weighed backbeam section displaying crash performance over the current design was suggested. Finally RCAR front low speed impact analyses were carried out for the optimized models.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.7 s.250
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• pp.622-629
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• 2006

The shape optimization of blade sweep in a transonic axial compressor rotor of NASA Rotor 37 has been performed using response surface method and the three-dimensional Wavier-Stokes analysis. Two shape variables of the rotor blade, which are used to define the rotor sweep, are introduced to increase the adiabatic efficiency of the compressor. Throughout the optimization, optimal shape having a backward sweep is obtained. Adiabatic efficiency, which is the objective function of the present optimization, is successfully increased. Separation line due to the interference between a shock and surface boundary layer on the blade suction surface is moved downstream for the optimized blade compared to the reference one. The increase in adiabatic efficiency for the optimized blade is caused by suppression of the separation due to a shock on the blade suction surface.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.7
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• pp.296-303
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• 1986

The active filter of current injection type is the device which eliminates the harmonics in ac line by injecting the harmonic compensating current into the ac side. And its harmonic reduction performance is entirely dependent on the control scheme of the current-fed inverter and the harmonic compensating current becomes the PWM wave by the inverter. This PWM compensating current can be determined by selecting the switching function properly which eliminates the harmonics up to any order with using no independent sources. The new injection current model is derived by the proposed method which is called the optimized injection method. The overall characteristics of the proposed method are investigated through digital computation and the feasibility is proved with experimental results obtained from the Z-80 microcomputer control of the active filter.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.3
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• pp.133-140
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• 1993

In this paper, we prpose a method for tracking optimally a spatial trajectory of the end-effector of flexible robot arms with multiple joints. The proposed method finds joint trajectories and joint torques necessary to produce the desired end-effector motion of flexible manipulator. In inverse kinematics, optimized joint trajectories are computed from elastic equations. In inverse dynamics, joint torques are obtained from the joint euqations by using the optimized joint trajectories. The equations of motion using finite element method and virtual work principle are employed. Optimal control is applied to optimize joint trajectories which are computed in inverse kinematics. The simulation result of a flexible planar manipulator is presented.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.263-266
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• 2004

This paper describes an intelligent piezoelectric traffic sensor which can be detected the over-weighted vehicles In motion. Based on finite element analysis for the sensor, the sensitivity was analyzed and the design was optimized. Studied parameters are the material properties of constitutional parts, the geometry of the sensor, the weight of the vehicle, and the speed of the vehicle. To verify the simulated results, we manufactured the sensor having the optimized geometry and the sensitivity was measured in the range from 0.5 to 3 ton of tensile and compressive stress. The measured results shows that the sensitivity and linearity of the sensor are closely agree with the designed values.

• 한국가시화정보학회:학술대회논문집
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• 2005.12a
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• pp.99-102
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• 2005

This study was conducted for obtaining the optimized data to build the mixer or micro fluid device as measuring the three dimensions flow field in micro mixer. To acquire the rapid diffusion on the region of low Reynolds (Re < 100), the staggered herringbone mixer using chaotic advection was selected in this case. At first, by conducting the numerical analytical virtual experiment using CFD-ACE+, three dimensions flow field in the micro mixer was estimated As this flow field was proven using defocusing particle tracing method, the behavior of micro flow with three dimensional aspects could be analyzed. Numerical analysis and flow pattern in the micro mixer by experimental verification made to be able to analyze the chaotic advection. These can be important sources for building more optimized form. Verifying the information of three dimensional flow structure, these information can be used as the data for developing and improving the $\mu$ -TAS.

• Journal of Power System Engineering
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• v.15 no.4
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• pp.31-36
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• 2011

The need for the lightweight of special vehicle trailer frame is substantially growing due to high gasoline prices and serious environmental issues. In this study, we develop a new lightweight sub-frame for large container trailers and evaluate its durability through a fatigue test. To this end, a reliable three-dimensional parametric finite element model of a sub-frame is constructed and then an optimized lightweight sub-frame is newly developed by using the Taguchi method. Next, we make a trial product of the optimized lightweight sub-frame and conduct a driving test to identify the driving load history at vulnerable areas. Finally, we evaluate the durability of the developed lightweight sub-frame through a fatigue test based on the load history.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1350-1354
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• 2007

As the importance of low power design is emphasized, power consumption became one of the standards that represent the performance of the system. The purpose of this study is to decide design variable that minimize power consumption for the oxygen concentrator in two bed-one compressor 8 step PSA process that has above 90% purity at 3lpm by using given constants and selected parameters. Setting selected parameters as cycle time and equalization time, optimization for PSA process in the oxygen concentrator is progressed. For this, we need to know the features and basic principals of PSA process and to deduce objective function of performance analysis. Validations for objective function and lots of experiments are needed too. By using the characteristic curve of the compressor and the pressure curve of the process for 1 cycle, objective function was set. After theoretical 2 dimensional optimized paths was obtained. And then, by experiment, theoretical optimized path was verified.