• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.985-988
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• 2008

A linear analysis method using reduced secant stiffness was developed for inelastic earthquake design of reinforced concrete structures. In the proposed method, the beam-column element and plane element, which are the same as used in conventional elastic analysis, are used for structural modeling. Based on the structural plastic mechanism intended by engineer, the distribution of inelastic members is determined. The secant stiffness of the inelastic members is determined based on the target ductility of the structure. Inelastic strengths of the members are calculated by using linear analysis on the structure modeled with secant stiffness. Plastic rotations in the inelastic members are calculated with the nodal rotations resulting from the secant stiffness analysis. For verification, the proposed method was applied to the inelastic earthquake designs of a moment-resisting frame and a dual system of two dimensions, and also a dual system of three dimensions.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.4
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• pp.343-348
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• 2019

In this paper, a dual-band antenna is proposed for the autonomous vehicle as well as omni-directional. The proposed antenna operates in the 4G/LTE band (1,710~2,170MHz) and 5G/NR band (3,400~3,700MHz). In order to obtain the dual-band operation, the planar monopole antenna is proposed as the novel structure with single port of the 50ohm. To give the properties of dual-band, an additional antenna element with slit was added to the planar monopole antenna, and then a structural adjustment parameter was optimized for achieving the target performance in bands. The planar monopole antenna in the LTE band acts as the coupled feed for the added parasitic radiator in the 5G NR band. The proposed antenna has $38.5{\times}36.0{\times}1.0[mm^3]$ on a ground with diameter of 96mm. From the fabrication and measurement results, the impedance bandwidth (VSWR<2) of the proposed antenna covers 1,480~2,260MHz (LTE band: 1,710~2,170MHz) and 3,310~3,930MHz (5G NR band: 3,400~3,700MHz). The proposed planar monopole antenna also obtained the measured gain and radiation pattern of omni-directional radiation pattern in the anechoic chamber.

• Bulletin of the Korean Chemical Society
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• v.35 no.9
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• pp.2655-2659
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• 2014

Dual specificity protein phosphatase 4 (DUSP4) has been considered a promising target for the development of therapeutics for various human cancers. Here, we report the first example for a successful application of the structure-based virtual screening to identify the novel small-molecule DUSP4 inhibitors. As a consequence of the virtual screening with the modified scoring function to include an effective molecular solvation free energy term, five micromolar DUSP4 inhibitors are found with the associated $IC_{50}$ values ranging from 3.5 to $10.8{\mu}M$. Because these newly identified inhibitors were also screened for having desirable physicochemical properties as a drug candidate, they may serve as a starting point of the structure-activity relationship study to optimize the medical efficacy. Structural features relevant to the stabilization of the new inhibitors in the active site of DUSP4 are discussed in detail.

• The Journal of the Acoustical Society of Korea
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• v.20 no.5
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• pp.100-109
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• 2001

The backscattered sound energy by fish depends on size and physical structure and, most important, on the presence or absence of a swimbladder. Target strength experiments of red seabream (Pagrus major) were conducted by using 38 (split-beam), 120 (split-beam) and 200 kHz (dual-beam) frequencies with live fishes confined in a net-cage and free swimming in tank without the cage, respectively. For 38, 120, and 200 kHz frequencies, target strength equations are expressed as a function of fish length：TS/sub 38kHz/=20 log/sub 1o(l)/-66.41, TS/sub 120kHz/＝20 log/sub 1o(1)/-71.80, and TS/sub 200kHz/＝20 log/sub 1o(1)/-73.94. To test the acoustic models by using Helmholtz-Kirchhoff ray approximation, predictions of target strength based on swimbladder morphometries are compared with target strength measurements. The target strength of whole fish depends on variations in swimbladder morphology than fish body morphology. In the mean time, when the fish is confined in the net cage, scattering length by the backscattered signal matched with the Gaussian PDF, while under the free-swimming condition, scattering length is close to the Rayleigh PDF.

• Smart Structures and Systems
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• v.26 no.4
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• pp.481-493
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• 2020

The negative stiffness spring and inerter are both characterized by the negative stiffness effect in the force-displacement relationship, potentially yielding an amplifying mechanism for dashpot deformation by being incorporated with a series tuning spring. However, resisting forces of the two mechanical elements are dominant in different frequency domains, thus leading to necessary complementarity in terms of vibration control and the amplifying benefit. Inspired by this, this study proposes a Negative Stiffness Inerter System (NSIS) as an earthquake protection system and developed analytical design formulae by fully utilizing its advantageous features. The NSIS is composed of a sub-configuration of a negative stiffness spring and an inerter in parallel, connected to a tuning spring in series. First, closed-form displacement responses are derived for the NSIS structure, and a stability analysis is conducted to limit the feasible domains of NSIS parameters. Then, the dual advantageous features of displacement reduction and the dashpot deformation amplification effect are revealed and clarified in a parametric analysis, stimulating the establishment of a displacement-based optimal design framework, correspondingly yielding the design formulae in analytical form. Finally, a series of examples are illustrated to validate the derived formulae. In this study, it is confirmed that the synergistic incorporation of the negative stiffness spring and the inerter has significant energy dissipation efficiency in a wide frequency band and an enhanced control effect in terms of the displacement and shear force responses. The developed displacement-based design strategy is suitable to utilize the dual benefits of the NSIS, which can be accurately implemented by the analytical design formulae to satisfy the target vibration control with increased energy dissipation efficiency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.11
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• pp.1462-1467
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• 2018

A number of algorithms for improving the image quality of low light images have been studied using a single image or multiple exposure images. The low light image is low in contrast and has a large amount of noise, which limits the identification of information of the subject. This paper proposes the hardware design of algorithms that improve the quality of low light image using 2 multiple exposure images taken with a dual camera. The proposed hardware structure is designed in real time processing in a way that does not use frame memory and line memory using transfer function. The proposed hardware design has been designed using Verilog and validated in Modelsim. Finally, when the proposed algorithm is implemented on FPGA using xc7z045-2ffg900 as the target board, the maximum operating frequency is 167.617MHz. When the image size is 1920x1080, the total clock cycle time is 2,076,601 and can be processed in real time at 80.7fps.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.3
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• pp.461-466
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• 2019

In this paper, we have studied the improvement of gain and bandwidth characteristics by using double feeding and L-shaped inset feed line matching circuit in microstrip stacked patch antenna which is widely used to broaden the gain of general microstrip antenna. The proposed structure is composed of two feeding edges of the main patch antenna, each of them are connected to a feeding line having an L shaped inset feeder. And the parasitic patch is placed at a proper distance above the main patch. The size of the main patch is designed so that the resonance frequency is close to the center frequency of the target frequency band. The experimental results show that the bandwidth was increased more than 180MHz in the 2.3-2.7 GHz band, which is more interesting than the single feed, and the gain improvement of 2.5dBi was obtained at 2.7GHz.

• Journal of IKEEE
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• v.26 no.2
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• pp.265-270
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• 2022

This paper proposes the detection algorithm for switch open fault of asymmetric 6-phase PMSM based on stationary reference frame dq-axis currents. In this paper, target motor has an asymmetric structure in which two upper three windings have an electrical phase difference of 30° and a neutral point is separated. As a result, dual 3-phase PWM inverters and the detection techniques due to open failures of switch are definitely required. In this paper, the dual dq-axis current control method is used for driving the asymmetric 6-phase PMSM and the open fault switch should be detected by using variable all pass filter and low pass filter in order to detect the current amplitude. The effectiveness and usefulness of the proposed method is verified by several experiments.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.7-10
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• 2006

In order to inject satellites into a target orbit, launch vehicles should have a precise attitude and control system capable of controlling three axises of pitch, yaw and roll. For launch vehicles, there are two types of attitude control system currently in popular use; the first one is a cold gas method, and the other is a liquid propulsion system using a single and dual property propellant. The purpose of this paper is to analyze the characteristics of thrust control system using said propellant, thereby providing for a rationale for its application to the upper stages of launch vehicles, in terms of the simplicity of the system, economics of structure and operation.

• The Plant Pathology Journal
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• v.26 no.3
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• pp.209-215
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• 2010

Plant pathogenic oomycetes, such as Phytophthora spp., are the causal agent of the most devastating plant diseases. During infection, these pathogens accomplish parasitic colonization of plants by modulating host defenses through an array of disease effector proteins. These effectors are classified in two classes based on their target sites in the host plant. Apoplastic effectors are secreted into the plant extracellular space, and cytoplasmic effectors are translocated inside the plant cell, through the haustoria that enter inside living host cell. Recent characterization of some oomycete Avr genes showed that they encode effector protein with general modular structure including N-terminal conserved RXLR-DEER motif. More detailed evidences suggest that these AVR effectors are secreted by the pathogenic oomycetes and then translocated into the host plant cell during infection. Recent findings indicated that one of the P. infestans effector, Avrblb2, specifically induces hypersensitive response (HR) in the presence of Solanum bulbocastanum late blight resistance genes Rpi-blb2. On the other hand, another secreted RXLR protein PexRD8 originated from P. infestans suppressed the HCD triggered by the elicitin INF1. In this review, we described recent progress in characterized RXLR effectors in Phytophthora spp. and their dual functions as modulators of host plant immunity.