• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.7
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• pp.1115-1121
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• 2001

In this paper, we analyzed the performance of GFSK system that presence fading effect in indoor radio communication environments and impulsive electromagnetic noise from electronic equipments then we applied the Truncated Type- II Hybrid ARQ scheme to make satisfied in data transmission service. As a result, the system was influenced by fading and impulsive electromagnetic noise. Especially, the system was much degraded by high occurrence frequency and amplitude of impulsive electromagnetic noise than fading which has direct frequency. By adopting the Truncated Type-II hybrid ARQ technique we can also obtained the performance improvement in the low signal power(20 dB) arid over 24 dB in strong impulsive electromagnetic noise environment which is occurred error floor and terribly influenced by the system.

• Journal of The Korean Association For Science Education
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• v.14 no.1
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• pp.24-33
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• 1994

This study is aimed at categorizing the CAl programs through analyzing the 82 science CAl programs developed by KEDI( Korean Educational Development Institutes ) and the 19 science CAl programs developed by the teachers who won the prizes in the first national educational software contest. The findings are as follows. 1) The main types of science CAl programs developed by KEDI are hybrid design type of tutorials and simulations, tutorials, and hybrid design type of instructional games and drill and practice. The other type of programs are very few. 2) The main types of science CAl programs developed by the teachers, who won the prizes in 1st educational software contest, are tutorials and hybrid design type of tutorials and simulations. There is no other type of programs except only two simulation type programs. 3) The science CAl programs developed by KEDI as well as by teachers who won the prizes in the contest are biased in two or three types, and the trend is severe in the programs developed by the teachers.

• 한국전산유체공학회:학술대회논문집
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• 2009.04a
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• pp.112-115
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• 2009

In this paper, flow simulation algorithms for utilizing unstructured hybrid meshes are introduced. First, various types of meshes are introduced. Advantages and disadvantages of each type of meshes are discussed. Unstructured hybrid mesh approach, that is best suited for high speed viscous flow simulation, is presented. Lastly, various types of flow simulations using unstructured hybrid meshes are introduced.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.5
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• pp.893-898
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• 2003

This paper proposes a Truncated Type-II Hybrid ARQ scheme and coding techniques using an adaptive modulation system to achieve high throughput data transmission systems for wireless multimedia communication systems. In this paper, the adaptive modulation system analyzed in Nakagami (m-distribution) fading channel environment. The adaptive modulation system controls the modulation level and symbol rate according to the Nakagami fading parameter(m). When the received Eb/No is high or the Nakagami fading parameter m is high, the propose system selects higher modulation level and higher symbol rate to increase throughput. On the other hand, this system selects lower modulation level and lower symbol rate to prevent throughput performance degradation when the received Eb/No is low. The modulation method have been adopted QPSK(Quadrature Phase Shift Keying), 16QAM(Quadrature Amplitude Modulation), 64QAM, 256QAM. Therefore, adaptive modulation systems with truncated type-II hybrid ARQ scheme is proper for wireless multimedia communication system that require high reliability and delay-limited applications.

• Land and Housing Review
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• v.3 no.1
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• pp.89-96
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• 2012

The purpose of this study was to evaluate the applicability of hybrid ventilation system in apartment housings and present a design method to improve the performance of hybrid ventilation system using the CFD simulation. As the object of CFD simulation, a small apartment houses with area of $51m^2$ and $81m^2$ were selected and evaluated. The test hybrid ventilation system are window frame natural air supply & duct exhaust hybrid system(Hybrid 1) and window frame natural air supply & bathroom and livingroom exhaust hybrid ventilation system(Hybrid 2). To evaluate the ventilation efficiency, we used the locations of diffuser installed for each system as the variables through the CFD simulation. In the case of Hybrid 1, the ventilation efficiency of the exhaust duct diffuser located on the inside room was higher rather than the exhaust duct diffuser located on the entrance. In the case of Hybrid 2, the most efficient system was the system that the diffuser connecting the bathroom static pressure fan is installed on the center of the living room. The ventilation efficiency of the Hybrid 2 in the case of $51m^2$ type was more than 20% of the Hybrid 1. But, The ventilation efficiency of the Hybrid 2 in the case of $84m^2$ type was more than 14% of the Hybrid 1. Therefore, to apply the Hybrid ventilation, a study that considers various variable should be conducted.

• Journal of the Korean Wood Science and Technology
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• v.38 no.5
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• pp.405-413
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• 2010

A hybrid post and beam shear wall system with structural insulation panel (SIP) infill was developed as a part of a green home 'Han-green' project through post and beam construction for contemporary life style. This project is on-going at the Korea Forest Research Institute to develop a new building system which improves Korean traditional wet-type building system and stimulates industrialized wood construction practice with pre-cut system. Compared to the traditional wet-type infill wall components, the hybrid wall system has benefits, such as, higher structural capacity, better thermal insulation performance, and shorter construction term due to the dry-type construction. To build up the hybrid wall system, in previous, SIP infill wall components can be manufactured at factory, and then inserted and nailed with helically threaded nails into the post and beam members at site. Shear performance of the hybrid wall system was evaluated through horizontal shear tests. The SIP hybrid wall system showed higher maximum shear strength, initial stiffness, ductility, yield strength, specified strength, and the specified allowable strength than those of post and beam with light-frame wall system. In addition to this, the hybrid wall system can provide speedy construction and structural and functional advantages including energy efficiency in the building system.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 1999.02a
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• pp.121-124
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• 1999

A horizontal axle-type superconductor flywheel energy storage system has many great features such as extensibility and stability compared to the traditional vertical axle-type flywheel systems. In this paper, a prototype flywheel device with a horizontal axle is presented briefly, and the hybrid construction as an essential supplement in superconductor journal bearing design against the levitation drift is proposed.

• Proceedings of the KWS Conference
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• 2003.11a
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• pp.36-38
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• 2003

In order to understand the basic knowledge on the model of heat source in hybrid welding, authors have conducted finite element analysis to calculate heat distribution using three heat source models of non-split type and split type(Volume, Volume-Volume, Volume-Surface). From the research result, we can confirm that Volume-Volume heat source of split type is suitable for the analysis of heat distribution.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.2
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• pp.63-70
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• 2003

In this paper, an MFC (Mass Flow Controller) which is widely used in many semiconductor manufacturing processes for controlling the mass flow rate of a gas is designed and implemented using the PIC 16F876 of Microchip, Inc. The MFC implemented in this thesis has the form of hybrid-type, i.e., the mixed-type of the analog-type MFC, which has many problems such as low accurary, and digital-type MFC, which use an expensive DSP (Digital Signal Processor) and an ADC (Analog to Digital Convertor) with high precision. The MFC is consists of the sensor unit, the control unit and the actuator unit, and it has used the automatic calibration algorithm and the reference table method for the improvement of the performance.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.5
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• pp.605-612
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• 2005

The objective of this study was to evaluate the factors affecting the optimization of coagulation hybrid UF membrane processes for the reuse of secondary effluent from sewage treatment plant. The experimental results obtained from the UF membrane process showed that organic colloids in the size range of $0.2{\mu}m{\sim}1.0{\mu}m$ caused the most substantial influence on the fouling of UF membrane. When using a coagulation pretreatment to UF membrane, alum dosage of 50mg/L resulted in the least reduction in membrane permeate flux. Also, for the rapid mixing process, in-line mixer type was more efficient for organic removal than back mixer type. Therefore, it may be concluded that coagulation-UF hybrid membrane process comparing to UF alone process showed not only higher removal efficiency of organic matter, but also substantial improvement of permeate flux of UF membrane.