• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.10
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• pp.3224-3233
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• 1996

SPATE(Stress Pattern Analysis by Thermal Emission) can be effectively used to analyze the stress distribution of the orthotropic structure under the repeated load by non-contact. In this research, the measuring conception and method of stress intensity factor of orthotropic material using SPATE are suggested. The relationships between the maximum values of SPATE signal and $1/\sqrt{X'}$ (or $1/\sqrt{y'}$) are theoretically established in the vicinity of crack tip of the orthotropic material. It is certified through SPATE experiment that their linear quality is very excellent.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.3
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• pp.103-110
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• 2014

In this study, spur and helical box models of an existing machine tool are investigated using structural and fatigue analyses. As the helical box model is shown to have less stress and deformation than those characteristics of the spur box model, the helical box has more strength and more transmission efficiency on the structure. In terms of fatigue analysis, the helical box model has more repeated fatigue strength than that of the spur box model. These study results can be effectively utilized in the design of real gear boxes of machine tools by anticipating and investigating prevention and durability against damage.

• Smart Structures and Systems
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• v.18 no.4
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• pp.733-754
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• 2016

Structural optimization involves a large number of structural analyses. When optimizing large structures, these analyses require a considerable amount of computational time and effort. However, there are specific types of structure for which the results of the analysis can be achieved in a much simpler and quicker way thanks to their special repetitive patterns. In this paper, frequency constraint optimization of cyclically repeated space trusses is considered. An efficient technique is used to decompose the large initial eigenproblem into several smaller ones and thus to decrease the required computational time significantly. Some examples are presented in order to illustrate the efficiency of the presented method.

• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.6
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• pp.353-359
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• 2016

In this paper, we propose a high performance L1 cache structure for the high clock CPU. The proposed cache memory consists of three parts, i.e., a direct-mapped cache to support fast access time, a two-way set associative buffer to reduce miss ratio, and a way-select table. The most recently accessed data is stored in the direct-mapped cache. If a data has a high probability of a repeated reference, when the data is replaced from the direct-mapped cache, the data is stored into the two-way set associative buffer. For the high performance and fast access time, we propose an one way among two ways set associative buffer is selectively accessed based on the way-select table (WST). According to simulation results, access time can be reduced by about 7% and 40% comparing with a direct cache and Intel i7-6700 with two times more space respectively.

• Journal of Aerospace System Engineering
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• v.14 no.2
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• pp.28-35
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• 2020

In this paper, we present a design for a retraction-type actuator (ReACT) that has the characteristics of both thermomechanical metamaterials and displacement amplification mechanisms. The ReACT consists of an actuating bar, a diamond-shaped displacement amplification (DA) structure, and a slot for loading thin-film heaters formed through the actuating bar. When power is supplied to the thin film heater, the actuating bars contacting the heater thermally expand, and the diamond-shaped DA structures retract in the longitudinal direction. The performance characteristics of the ReACT, such as temperature distribution and retracting displacement, were calculated with thermomechanical analysis methods using the finite element method (FEM). Subsequently, the ReACTs were fabricated using a polymer-based 3D printer that can easily execute complex structures, and the performance of the ReACT was evaluated through repeated tests under various temperature conditions. The results of the performance evaluation were compared with the results of the FEM analysis.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1389-1390
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• 2008

In this paper, a This paper presents the Hilbert curve Fractal Antenna has properties of Self-similarity and Plane-Filling. In case of fractal antenna is very useful to be small and multiple resonant. The antenna has a resonant frequency of 910MHz and 2450MHz base on RFID(Radio Frequency IDentification). In particular, we designed tag antenna by the $4^{th}$ repeat. According to the repeated number of fractal structures, resonance frequency became looking downward. Theses presented Frequency, Such as 910MHz and 2450MHz, at $S_{11}$ is -31dB and -19dB, bandwidth 120MHz and 90MHz to VSWR 2:1.

• Wind and Structures
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• v.17 no.6
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• pp.671-680
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• 2013

Static aeroelastic is investigated in a wind turbine blade. Imposed to different loadings, the very long and flexible structures of blades experience some changes in its preliminary geometry. This results in variations of aerodynamic loadings. An iterative approach is developed to study the interactions between structure and aerodynamics evaluating variations in induced stresses in presence of aeroelasticity phenomenon for a specific wind turbine blade. A 3D finite element model of the blade is constructed. Aerodynamic loading is applied to the model and deflected shape is extracted. Then, aerodynamic loadings are updated in accordance with the new geometry of the deflected blade. This process is repeated till the convergence is met. Different operational conditions consisting of stand-by, start-up, power production and normal shut-down events are investigated. It is revealed that stress components vary significantly in the event of power production at the rated wind speed; while it is less pronounced for the events of normal shut-down and stand-by.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.731-736
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• 2000

An optimal design method is adopted for a spacer grid in nuclear power plant. It is made of punched sheet metal process, functioning as springs and dimples supporting fuel rods. For stress analysis of the assembled fuel rod support, a typical cell out of the repeated pattern in the assembly is modeled using 4-node shell elements. A commercial code, ABAQUS, is used for detailed analysis of contacting phenomena with friction. For the optimization, design varibles are taken from geometric parameters representing the shape of the bent leaf spring part and mating contact region with fuel rod. Objective function is considered in relation to mechanical functions and durability. Maximum yon Mises stress is considered in relation to constrained contact stress.

• Mycobiology
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• v.29 no.1
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• pp.43-47
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• 2001

Genetic diversity of 21 Korean Phytophthora capsici isolates was analyzed by using several molecular markers such as random amplified polymorphic DNA(RAPD), M-13, microsatellite and random amplified microsatellite sequences(RAMS). The overall average similarity coefficient among the isolates was 86% based on the combined data obtained by the molecular markers. No molecular markers were found to be associated with hosts or geographic regions. In addition to RAPD, analysis based on repeated sequences such as $(GTG)_5$, M-13 and RAMS could be used to assess population structure of P. capsici.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.169-169
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• 1998

Three analgesic constituents: FB2c, FB6Fc, and FB10E5c from the hexane extract of Mentha cordifolia Opiz. (Yerba buena) leaves were isolated by solvent partitioning and sequential repeated vacuum liquid chromatography. Spectral analysis of the three constituents show that FB2c is ${\beta}$-sitosterol; FB10E5c is ${\beta}$-sitosteryl-${\beta}$-D-glucopyranoside; and FB6Fc is a cis-8- pentadecenyl with lactone variety. At a dosage of 100 mg/kg mouse, isolates FB2c, FB6Fc, and FB10E5c decreased the number of squirms induces by acetic acid by 70.0 %, 67.3 %, and 73.0 %, respectively.