• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1232-1234
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• 1995

Specimem of silicone rubber used to make the weathersheds for High-Voltage composite insulator were aged in laboratory. The aging characteristics of silicone rubber have been assessed by compairing their hydrophobicity and electrical properties, before and after aging with weather ometer. Results show that their initial and time dependant characteristics are good.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.80-82
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• 2012

In this paper, we present electromagnetic modeling to design unclonable PUFs with frequency-dependant materials corresponding to Debye dispersion. To demonstrate FDTD calculations consider that 1-D problem of pulsed plane wave traveling in free space normally incident on air-silicon material interface. The pulse traveling wave at a vacuum-medium interface were reflected, and transmitted wave were dissipated. As a result, 1-D PUF with Debye dispersion material structure can be applied and FDTD calculation for PUF modeling is a good approximation.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.85-90
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• 2002

This paper concerns the within test strength of concrete cured under different conditions. Those conditions are water curing, field curing and cores drilled from the existing structures. The test factors are not only above cured conditions but also concrete ages of 3, 7, 14 and 28 days and concrete strength of 202, 252 and 650kgf/$\textrm{cm}^2$. The test results are as follows； (1) In spite of within test results, concrete strength is very different from curing states of concrete (2) The strength of cores drilled from existing structures are smaller than the strength of concrete cured in water by 3~4% and larger than that of concrete cured in field by 8~17% (3) Core strength is largely dependant on the curing state of top surface of concrete.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.342-345
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• 2004

An efficient hybrid ARQ scheme based on the rate compatible block turbo codes has been proposed, and its performance has been analyzed. System efficiency is improved by means of adaptive rate code transmission using channel information, trading off bit rate for channel codes, with resulting energy saving. The rate adaptation scheme improves power efficiency while keeping packet delay minimized. On the other hand, power dependant strategies reduce power consumption. Simulation results show that the benefits obtained are very encouraging. The modified hybrid ARQ schemes with the channel information and efficient retransmission structures highly improve the throughput performance in the satellite communication system. Therefore, proposed schemes could be used in future communication systems.

• Journal of Industrial Technology
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• v.36
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• pp.3-7
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• 2016

The change of flue gas residence time with the location of air inlet in an incinerator is analysed. An independent numerical variable is the location of air inlet and dependant is the residence time of flue gas. The mean value of turbulence energy in a primary combustion chamber is also analysed. The flow field and the distribution of turbulence energy are investigated to evaluate their influence on the residence time of flue gas and the turbulence energy. As the position of secondary air inlet approaches to the top of primary combustion chamber, the residence time of gas and the turbulence energy become longer and larger respectively.

• Journal of the Microelectronics and Packaging Society
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• v.18 no.3
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• pp.53-57
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• 2011

In the modern packaging technologies highly condensed metal interconnects are typically formed by highcost processes. These methods inevitably require the precise controls of mutually dependant process parameters, which usually cause the difficulty of the change in the layout design for interconnects of chip to-chip, or chip-to-substrate. In order to overcome these problems, the unique concept and methodology of self-assembly even in micro-meter scale were developed. In this report we focus on the factors which influenced the self-formed bumps by analyzing the phenomenon experimentally. In case of RMA flux, homogenous pattern was obtained in both plain surface and cross-section surface observation. By using RA flux, the phenomena were accelerated although the self-formtion results was inhomogenous. With ussage of moderate RA flux, reaction rate of the self-formation was accelerated with homogeneous pattern.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.2
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• pp.254-263
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• 2015

In this study, numerical simulations are carried out to investigate the dynamic SGS model effects in a Kerosene-LOx coaxial swirl injector under high pressure conditions. The turbulent model is based on large-eddy simulation (LES) with real-fluid transport and thermodynamics. To assess the effect of the dynamic subgrid-scale (SGS) model, the dynamic SGS model is compared with that of the algebraic SGS model. In a swirl injector under supercritical pressure, the characteristics of temporal pressure fluctuation and power spectral density (PSD) present comparable discrepancies dependant on the SGS models, which affect the mixing characteristics. Mixing efficiency and the probability density (PDF) function are conducted for a statistical description of the turbulent flow fields according to the SGS models. The back-scattering of turbulent kinetic energy is estimated in terms of the film thickness of the swirl injector.

• The Korean Journal of Health Service Management
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• v.10 no.3
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• pp.13-25
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• 2016

Objectives : The purposes of this study was to analyze business performance of university hospitals for the past 10 years. Methods : Management and finance data from 2005 to 2014 were collected from balance sheets, income statements and annual reports from 27 university hospitals. The dependant variable used was profitability which included return on assets, operating margin and net profit to gross revenues 1. The independent variables were general characteristics, liquidity, stability, activity and financial ratios. Results : University hospitals over the last 10 years had achieved good management performance. Using financial leverage, patient revenues, operating profit, nonpatient revenues, total assets and total debt, the total amount had increased by more than double. The ratio of fixed liability and fixed assets turnover was found to have a significant positive (+) effect on management performance in the years 2012-2014. Conclusions : Based on these results, this study suggests a more in-depth analysis using fixed liabilities and fixed assets.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.6
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• pp.1755-1763
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• 2015

The objective of this study is to empirically analyze the relationship between sea temperature and jellyfish blooms. Ever since the 2000s, jellyfish population has been dramatically increased, which brought negative influence on the national health and the fisheries activities. Jellyfish blooms have been recognized as an effect of climate change, but there has been no empirical evidence to support such relationship. In this paper, the relationship between sea temperature and jellyfish blooms has been analyzed by using the regional jellyfish monitoring data and coastal stationary observing data of National Institute of Fisheries Science. Since the dependant variable carries left censoring issues, we used the panel tobit model. Our results indicate that there are statistically significant positive relationship between sea temperature and jellyfish blooms.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.68-71
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• 2003

Heat treatment is one of the critical manufacturing processes that determine the quality of a product. This paper presents experimental and analytical results for the quench of a ring gear in stagnant oil. The goal of this study is to develop heat transfer predicting model in an overall analysis of the quenching process. Thermal conductivities which are dependant on temperatures and convection coefficients which are obtained by inverse method are used to develop the accurate heat transfer model. The results of heat transfer model have a good agreement with experimental results.