• Proceedings of the KSME Conference
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• 2005.11a
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• pp.38.2-38.2
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• 2005

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.5
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• pp.572-581
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• 2008

The performance of a barrel stave flextensional transducer is determined by the properties of its constituent materials and the effects of many structural parameters. In this study, with the finite element method, the structure of a barrel stave flextensional transducer was optimized to achieve the widest bandwidth while satisfying the requirements on pressure and center frequency. The optimization was carried out with the SQP-PD method for multi-variable minimization. The optimized barrel stave flextensional transducer satisfied all the required specifications.

• Journal of the Korean Operations Research and Management Science Society
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• v.26 no.4
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• pp.1-21
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• 2001

The purpose of this stuffy is to derive critical success factors for ERP system implementation by integrating managerial, technical. human resource and organizational culture factors welch have been proposed as influencing factors for the performance of ERP system implementation in previous studios. Especially, this stuffy divides ERP system implementation process into preparation stave, implement stage and settle-down and stabilization stave, and then derives critical success factors in each stage. The data for empirical analysis of the research model are collected from 64 companies and the respondents for questionnaire consist of ERP system implementation project managers and user department managers in companies which have already operated it after ERP system installation. The main results of this study are as follows. First, it derives 27 success factors through comprehensive review of various factors which may affect ERP system implementation performance, and categorizes them into one of three stapes preparation stave, implement stage, and settle-down and stabilization stage. Second, the relationship between many success factors at each stave (preparation stave, implement stage, and settle-down and stabilization stave) and performance variables is tested. As a result, the significant correlations between many success factors at each stage and ERP system implementation performance are found, and the difference among success factors in the degree of influencing the system performance is significantly shown. finally, the relationship between process-oriented performance variables and result-oriented performance ones is tested. As a result, it is found that there is significant correlation between process-oriented performance variables except for one variable-project resource management appropriateness - and result-oriented performance ones. The theoretical contribution of this study is to derive a comprehensive model of critical success factors for implementing ERP system project from the system deve1opment life cycle perspective, and empirically test it through field survey with a wide range of data collection. And, the practical implication of this study is to present the desirable guidelines for performing ERP system implementation project successfully.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.3
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• pp.329-334
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• 2011

The cooling water circulation plates had been used to drop the temperature of refractory outside shell of common cooling system by using cooling plate or stave type. When they are attacked by surrounding gas, they are corroded and the water flows in the refractory due to leakage of water. So, the life of refractory material is shortened and changed due to the worse conditions of cooling system. The automatic sensing device for water leakage of cooling plate is developed to check the position of trouble by using the microprocessor system when cooling water leak and gas are flowed into the cooling plate through the leakage position. The flowed gas is detected in the micro-process system which delivers the detected position of cooling plate or stave to main control room through the wireless-radio relay station. This system can be possible to detect the position of cooling plate or stave against the water leakage part immediately and then deliver the signal to main control room by using the microprocessor system and wireless-radio relay station. This system will be developed in changing the working condition from manual system to unmanned auto alarm system.

• 전자공학회논문지 IE
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• v.46 no.4
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• pp.25-30
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• 2009

The cooling water circulation pipes had been used to drop the temperature of refractory outside shell of blast furnace by cooling plate or stave type. They were attacked by surrounding CO gas and it was the cause that they were corroded and the water inflow in the refractory due to leakage of water. So, the life of refractory material was shorten and changed for the worse the conditions of blast furnace. The automatic sensing device for water leakage of cooling pipe was developed to check the position of trouble by use the micro-process system when cooling water leak and then CO gas will be inflowed into the cooling pipe at the leakage position. The inflowed CO gas will be detected in the micro-process system and delivered the detected position of cooling plate or stave to main control room through the wireless-radio relay station. This system can be possible to detect the position of cooling plate or stave the water leakage part immediately and then deliver the signal to main control room by use the micro-process system and wireless-radio relay station. This system will develop the working condition from manual system to unmanned auto alarm system.

• Journal of the Korean Institute of Telematics and Electronics
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• v.12 no.2
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• pp.43-46
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• 1975

In a chopper amplifier the input signal of the AC amplifier is a train of square-waves. In the rase of square-wave the operatiom of AC amplifier is much different from that of ordinary sinusoidal wave. In this paper for the purpose of contributing to the design of chopper amplifier destortions of waveforms in the amplifier were investigated. When the time constant of each stage is equal the waveform in each stave apppears as square wave whose top is exponentially decaying. And when each stave has different time constant the waveform in n-th stage is composed of n-square waves whose tops are exponentially decaying.

• BMB Reports
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• v.38 no.5
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• pp.507-516
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• 2005

Antimicrobial peptides (AMPs) have been isolated and characterized from tissues and organisms representing virtually every kingdom and phylum. Their amino acid composition, amphipathicity, cationic charge, and size allow them to attach to and insert into membrane bilayers to form pores by 'barrel-stave', 'carpet' or 'toroidal-pore' mechanisms. Although these models are helpful for defining mechanisms of AMP activity, their relevance to resolving how peptides damage and kill microorganisms still needs to be clarified. Moreover, many AMPs employ sophisticated and dynamic mechanisms of action to carry out their likely roles in antimicrobial host defense. Recently, it has been speculated that transmembrane pore formation is not the only mechanism of microbial killing by AMPs. In fact, several observations suggest that translocated AMPs can alter cytoplasmic membrane septum formation, reduce cell-wall, nucleic acid, and protein synthesis, and inhibit enzymatic activity. In this review, we present the structures of several AMPs as well as models of how AMPs induce pore formation. AMPs have received special attention as a possible alternative way to combat antibiotic-resistant bacterial strains. It may be possible to design synthetic AMPs with enhanced activity for microbial cells, especially those with antibiotic resistance, as well as synergistic effects with conventional antibiotic agents that lack cytotoxic or hemolytic activity.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.173-173
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• 2006

We have explored a strategy to control the supramolecular nano-structures self-assembled from rigid segments through attachment of flexible chains through microphase separation and anisotropic arrangement. Supramolecular structures formed by self-assembly of rigid building blocks can be precisely controlled from 1-D layered, 3-D bicontinuous cubic to 2-D cylindrical structures by systematic variation of the type and relative length of the respective blocks. Furthermore, depending on the individual molecular architectures, rigid building blocks self-assemble into a wide range of supramolecular structures such as honeycomb, disk, cylinder, helix, tube, barrel stave, and nano-cage.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.90-91
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• 2011

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.4
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• pp.323-330
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• 2002

In this paper, we have designed and fabricated an BWLL MMIC amplifier using GaAs PHEMT devices. We have optimized power divider/combiner size for small size of MMIC amplifier Using 0.2 ${\mu}$m AIGaAs/lnGaAs/GaAs PHEMT devices, the two stave MMIC amplifier has demonstrated a S$_{21}$ gain of 8.7 ㏈ with input/output return losses of lower than -10 ㏈ at 26.7 GHz. The size of this chip is 4.11 ${\times}$ 2.66 $\textrm{mm}^2$.