• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.6
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• pp.2835-2850
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• 2016

RSA is a public key cryptosystem that is currently the most popularly used in information security. Development of RSA variants has attracted many researchers since its introduction in 1978 by Ron Rivest, Adi Shamir, and Leonard Adleman. In this paper, we propose an algebraic structure for RSA and show that the proposed structure covers all known RSA variants. The usefulness of the proposed structure is then proved by showing that, following the structure we can construct a RSA variant based on the Bergman ring. We compare the original RSA and its variants from the point of view of factoring the modulus to determine why the original RSA is widely used than its variants.

• Publications of The Korean Astronomical Society
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• v.10 no.1
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• pp.67-78
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• 1995

An introduction to the first CCD camera system in Bohyunsan Optica1 Astronomy Observatory(CCD#l) is presented. The CCD camera adopts modular dewar design of IfA(Institute for Astronomy at Hawaii University) and SDSU(San Diego State University) general purpose CCD controller. The user interface is based on IfA design of easy-to-use QUI program running on the NeXT workstation. The characteristics of the CCD#l including Gain, Charge Transfer Efficiency, rms Read-Out Noise, Linearity and Dynamic range is tested and discussed. The CCD#l shows 6.4 electrons RON and gain of 3.49 electrons per ADU, and the optimization resulted in about 27 seconds readout time guaranteeing charge transfer efficiency of 0.99999 for both direction. Linearity test shows that non-linear coefficient is $6{\times}10^{-7}$ in the range of 0 to 30,000 ADU.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.69-72
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• 2008

The local water contents and water transfer characteristics in the PEMFC system were investigated by numerical simulations and experiments. The performance of a lab-scale PEMFC is measured for fully humidified gases conditions and non-humidified ones. In order to observe the local water contents and water transfer characteristics inside PEMFC, the numerical simulation using CFD module on STAR-CD(es-pemfc) were conducted. The results show that the water content was increased as increasing current density, whereas it was decreased in high current density region. Then there was close correlation between high water content and internal temperature inside of MEA, and high current density was observed when internal temperature was dramatically increased.

• Journal of the korean Society of Automotive Engineers
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• v.14 no.5
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• pp.61-68
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• 1992

Knock phenomenon is an abnormal combustion originated from autoignition of unburned gas in the end-gas region during the later stage of combustion process and it accompanys a high pitched metallic noise. Engine Knock is accompanied with a vibration of engine cylinder and when it is severe, it can cause major engine demage. Engine Knock is characterized in terms of knock crank angle, knock pressure, pressure jump and knock intensity. In this study, a 4-cylinder spark ignition engine was used for experiment and eighty consecutive cycles were analyzed statistically. The purpose of this study is to characterize spark ignition engine knock as a function of ignition timing and fuel research octane number. The result of this study can be summerized as follows. Knock occurrence angle approached TDC as ignition timing is advanced. Pressure and knock intensity gradually increased as spark timing is advanced. Mean knock occurence angle gradually approached TDC as fuel research octane number is decreased for identical spark timing. Knock intensity increased linearly as RON is decreased.

• Journal of Biomedical Engineering Research
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• v.7 no.1
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• pp.67-74
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• 1986

We have implemented data compression and reconstruction by using a fast Walsh transform. The ECG signals were generated by an ECG BimLllator (KONT- RON). The sampling frequency was 480 Hz and the data point number used was 512. In order to eliminate the 60 Hz noise and baseline drift, a digital notch filter was designed. We obtaine!1 a compression ratio of 5 : 1 and at this ratio it was possible to obtain a true diagnosis and an ECG morphology analysis.

• Microbiology and Biotechnology Letters
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• v.45 no.4
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• pp.354-357
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• 2017

There is an increase in the presence of drug-resistant staphylococci outside of the nosocomial and healthcare setting. Although the presence of staphylococci has been studied in several public spaces, nothing is known on the presence of staphylococci in public libraries. Book surfaces from public libraries in the East London area, United Kingdom were swabbed and cultured and identity of the isolates determined by matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry (MS). Seven different staphylococcal species were identified by MALDI-TOF-MS analysis. This short study provides evidence of the presence of multidrug-resistant staphylococci in public libraries in the East London area.

• Journal of the Korean earth science society
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• v.21 no.6
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• pp.695-702
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• 2000

The ichnogenus Protovirgularia McCoy, 1850 is reported from nonmarine strata of the Cretaceous Jinju Formation of the Sacheon area Korea. There, the Jinju Formation is composed mainly of fine-grained sandstone, grey to brownish grey mudstone, and shale which were deposited in a freshwater lacustrine environment. This occurrence represents the fist formal recording of the ichnotaxon from Korea and the first, on a global basis, from a nonmarine depositional environment.

• Journal of electromagnetic engineering and science
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• v.2 no.1
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• pp.5-10
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• 2002

We have analized the inverse class-F and class-F amplifiers using their waveforms. From the analytic equations derived from the analysis, we have calculated tole efficiencies, output powers, DC power dissipations, and optimum fundamental load impedances of the inverse class-F and class-F amplifiers. We also have compared them for various operation conditions, which include the same peak current, saute DC power dissipation, same fundamental RF output power, and same fundamental load impedance with different Ron(on-resistance). These analyses have clearly shown the performance limitations, advantages, and guide to the optimized design of the inverse class-F amplifiers.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.217-220
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• 2002

In this paper, we have investigated electronical chara-cteristics of power LDMOSFETS having different ex-tended gate lengths(1.B${\mu}{\textrm}{m}$, 2.4${\mu}{\textrm}{m}$, 3.O${\mu}{\textrm}{m}$) in the temperature range of 300k-500K. The results of this study indicate that on-resistance, breakdown voltage increase with temperature. and drain current, threshold voltage, transconductance decrease with temperature. Particular the facts, we observed that Le is the more increase, on-resistance is the more decrease. because every conditions are fixed normal states, only change the Le. As a result, Ron/BV, known for a figure of merit of power device, increase with temperature.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1057-1060
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• 2003

This paper is about the optimized fabricated parameter in the EDMOSFET(Extended drain MOSFET) with a various temperature. As we know, the two important factors of EDMOSFET parameters are breakdown voltage and on Resistance. So, we have aims of the power EDMOSFET design to have high breakdown voltage and low on resistance. Thus in this paper, we will show the figure of merit in LDMOS (BV/Ron) in accordance with increase in temperature(300K-500K, step:50K), and measure electronic characteristics of power EDMOSFET. As a result, the important factors in design of EDMOS are temperature and Lg.