• Journal of the Chungcheong Mathematical Society
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• v.27 no.4
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• pp.563-569
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• 2014

We investigate a minimal set of generators of a homogeneous ideal of a curve of degree d on a linearly normal smooth surface scroll W in $P^r$ whose arithmetic genus is maximal among curves of degree d on W.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.1039-1042
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• 2007

Motion blur of LCD displays has been measured subjectively by using Gabor patch radiusese. Gabor radiuses at a normalized scroll speed, Scroll speed times Fc, to be unity, indicate motion blur strengths, which are named a perceived motion blur strength measured by a Gabor patch. The results are compared with eye perception, PBET and EBET.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2069-2071
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• 2001

In this paper, a transmitter and a receiver using two identical Hyper-Chaos that n-double scroll circuits are proposed and a hyper-chaos synchronizations are investigated. we are proposed unidirectional coupling of ide n-double scroll cell for hyper-chaos synchronizat. We've shown that simulation result is synchronization.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2072-2074
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• 2001

In this paper, a transmitter and a receiver using two identical Hyper-Chaos that n-double scroll circuits are proposed and a hyper-chaos synchronizations and secure communication are investigated. we are proposed unidirectional coupling of identical n-double scroll cell for hyper-chaos synchronization. We've shown that simulation result is synchronization and secure communication.

• The Journal of Korean Association of Computer Education
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• v.5 no.4
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• pp.134-145
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• 2002

The purpose of this study is to present the functional and technical solutions for text learning of web-based textbook in which each letter has its own focal point. The solutions help learners not to lose the main focus when eye moves to the next letter or line. The text screen of the electronic textbook automatically scrolls the text to up and down or left and right directions which are preassigned by learner. It doesn't need the operation of mouse or keyboard. And learner can change scroll speed and types anytime during scrolling. Automatic text scroll function is a solution for controlling data and screen to reflect the personal favor and ability. It contains the content structure of the text(characteristics, categorizations etc.), the appearance of the text(density, size, font etc.), scroll options(scroll, speed etc.), program control type(ram resident program etc.), and the application of the screen design principles(legibility etc.). To resolve these functional problems, technical 8 phases are provided, which are environment setting, scroll option setting, copy, data analysis, scroll coding, centered focus coding, left and right focus coding, implementation. The learner can focus on text without dispersion because the text focal points stay in the fixed area of screen. 1bey read the text following their preferences for fonts, sizes, line spacing and so on.

• The KSFM Journal of Fluid Machinery
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• v.3 no.1 s.6
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• pp.19-27
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• 2000

A numerical study is presented for analysis of three-dimensional incompressible turbulent flows in a multi-blade centrifugal fan. Reynolds-averaged Navier-Stokes equations with a standard $k-{\espilon}$ turbulence model are discretized with finite volume approximations. The computational area is divided into three blocks; inlet core, impeller and scroll parts, which are linked by a multi-block method. The flow inside of the fan is regarded as steady flow, and the mathematical models for the impeller forces were established from a cascade theory and measured data. Empirical coefficients are obtained comparing between computational and experimental results for the case without scroll, and are employed to simulate the flow through the impeller with scroll. In comparisons with experimental data, the validity of the mathematical models for the impeller forces was examined. The characteristics of the flow in the scroll were also discussed.

• Journal of Energy Engineering
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• v.21 no.4
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• pp.398-401
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• 2012

In this Study, efficiencies of the scroll expander under development for organic Rankine cycle using engine waste heat of vehicle have been analyzed and compared with the commercial scroll expander. While operating organic Rankine cycle for analysing expander efficiencies, power of expander, inlet temperature of expander, inlet pressure of expander and the flow rate of the working fluid(refrigerant R134a) have been measured. Overall efficiency of the expander has been shown the very low level compared with the overall efficiency of the commercial expander. Especially, because the low volumetric efficiency has much effect on overall efficiency, the working fluid leakage trouble of expander has to be solved surely for improvement of the expander overall efficiency.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.7 no.3
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• pp.366-381
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• 1995

A performance analysis of refrigeration system using the HFC-134a and scroll compressor is performed numerically. The refrigeration system mainly consists of various standard components such as heat exchanger, compressor, and expansion device. The model for heat exchanger performance is based on a tube-by-tube method which is analyzed separately by considering the cross-flow heat transfer with the outdoor air flow and pressure drop. Compressor is used the scroll-type compressor which has many merits such as high efficiency, low noise and vibration, and small in size. Short-tube is included as an expansion device. Vapour and liquid line are also considered for the performance analysis of refrigeration system. Using the modeling of various components of refrigeration system, a performance comparison of CFC-12 and HFC-134a is performed numerically for the various outdoor air temperature and various values of short-tube diameter. As the results of this study, the refrigeration system performance decreases as the outdoor air temperature increases. And the optimum short-tube diameter based on COP is 1.37mm for this system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.12
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• pp.776-781
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• 2011

The rapid increases in global energy demand and global warming need renewable energy sources such as solar thermal energy, biomass energy and waste heat. A ORC-based micro-CHP system(< 10 kWe) is one of the effective means to use renewable energy and solve energy problems because of its compactness, flexibilities and lower cost compared to other systems. The most important core components of the ORC is the expander which has a strong effect on the cycle efficiency. In the range of power output from 1 to 10 kW, the scroll expander is a good choice due to its performance and reliability. In this study, we have carried out an experimental study on an ORC equipped with oil-free scroll expander working with refrigerant R134a. We have measured power output and thermal efficiencies of the ORC and analyzed correlation between volumetric efficiencies of the expander and thermal efficiencies of the ORC.

• Journal of the Korean Solar Energy Society
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• v.34 no.3
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• pp.42-48
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• 2014

An experimental study was performed estimating COP(Coefficient of Performance) of air-conditioning cycle with inverter scroll compressor. All experiments were done for various compressor speeds from 1000~4000 rpm and used the inverter controller called CANDy to change the compressor rpm. The air-conditioning cycle components in the apparatus were used as same with components of YF hybrid car. To estimate the COP, this study measured the temperature and pressure at inlets and outlets of compressor, condenser, and evaporator. And also measured the compressor input power using Powermeter. Through the experiments, the maximum error to estimate COP was shown about ${\pm}6.09%$ at 3500rpm. This study revealed that the condenser temperature and pressure were increased and the evaporator temperature and pressure were decreased with the increased compressor speed. And also, the COP was decreased with increased compressor speed. Those results can be used the basic and fundamental data to design the air-conditioning cycle with inverter scroll compressor.