• Journal of Industrial Technology
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• v.28 no.A
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• pp.113-117
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• 2008

Wireless carrier sense multiple access (CSMA) systems are widely used but show extremely different transmission efficiency according to the operation environment. Simulation or prototype deployment is needed to see the transmission efficiency of a wireless CSMA system with the partial packet retransmission scheme. The lower bound for the transmission efficiency of such a system is found mathematically in this work. This shows how much the partial packet retransmission scheme improves the transmission efficiency quantitatively. It also shows that the maximum throughput is obtained at higher offered load compared to the conventional CSMA system without the partial packet transmission. The result of this work can be applied to IEEE 802.11 networks or wireless mesh networks.

• Bulletin of the Korean Chemical Society
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• v.28 no.8
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• pp.1383-1388
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• 2007

Recently, the semiconductor and display industries have tried to reduce the emissions of perfluorocompounds (PFCs) from the globally environmental regulation. Total amount of PFC emission can be calculated from the flow rate and the partial pressures of PFCs. For the precise measurement of PFC emission amount, the mass flow controlled helium gas was continuously injected into the equipment of which scrubber efficiency is being measured. The partial pressures of PFCs and helium were accurately measured using a mass spectrometer in each sample extracted from inlet and outlet of the scrubber system. The flow rates are calculated from the partial pressures of helium and also, PFC destruction and removal efficiency (DRE) of the scrubber is calculated from the partial pressure of PFC and the flow rate. Under this method, the relative expanded uncertainties of the flow rate and the partial pressures of PFCs are ± 2% (k = 2) in case the concentrations of NF3 and SF6 are as low as 100 μmol/mol.

• Proceedings of the KIPE Conference
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• 1998.11a
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• pp.39-43
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• 1998

A large number of soft switching topologies included a resonant circuit have been proposed. But these circuits increase number of switch in circuit and complicate sequence of switching operation. In this paper, the authors propose power conversion system, DC-AC inverter of high efficiency and high power factor with soft switching mode by partial resonant method. The switching devices in a proposed circuits are operated with soft switching by the partial resonant method, that is, PRS2MPC (Partial Resonant Soft Switching Mode Power Converter). The result is that the switching loss is very low and the efficiency of system is high. And the snubber condenser used in partial resonant circuit makes charging energy regenerated at input power source for resonant operation.

• Fire Science and Engineering
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• v.20 no.2 s.62
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• pp.72-79
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• 2006

The objective of this study is to analyze the smoke extraction efficiency using by the partial extraction system with CFD simulation for case of tunnel fire. The Comparison of CFD results with the preceding scaled model test results, it is equal to the smoke extraction efficiency and smoke stratification in tunnel by the partial smoke extraction system (distributed damper). It shows that the smoke extraction efficiency is increased about 7% by the distributed damper which is opened near fire, compare with the distributed damper which is all opened. The case of the fire occurs on a traffic jam in a tunnel, it is proposed that the operating method of partial smoke extraction system for the escaping passengers.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.9
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• pp.118-125
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• 1997

This paper proposed a new partial resonant 3.PHI. AC-DC boost converter of high efficiency using lossless snubber. The proposed converter, DCM (Discontinuous Current Mode) has a merit of simple controlled circuit because the input current control discontinuously. But turned off switching loss and stress of the switching device increase when the switch turned off at the peak of current. Therefore, the paper improves efficiency by adopting the PRS$^{2}$(Partial Resonant Soft Switching) in 3.PHI. AC-DC boost converter and makes the unity power factor. The PRS$^{2}$ is reduced a current/voltage stresses of switching devices. Also, a DCMPRS$^{2}$M(Discontinuous Conduction Mode Partial Resonant Soft Switching Method) appear the current and voltage equation of this circuit. The paepr examine in a 3.PHI. AC-DC boost converter and show the result of that.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.4
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• pp.212-218
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• 1999

A new partial resonant three phase boost converter with high power factor and high efficiency is proposed. The proposed boost converter is constructed by using a resonant network in parallel with the swithch of the conventional boost converter. The devices are switched at zero voltage or zero current eliminating the switching loss. A new auxiliary partial resonant boost converter achieves zero-voltage switching(ZVS) or zero-current switching(ZCS) for all switch devices without increasing their voltage and current stresses.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.531-532
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• 2006

This paper presents our implemented, synthesized and tested on demand and partial reconfiguration approaches for FIR filters using Xilinx Virtex FPGAs. Our scope is to implement a low-power, area-efficient autonomously reconfigurable digital signal processing architecture that is tailored for the realization of arbitrary response FIR filters on Xilinx Virtex4 FPGAs. The implementation of design addresses area efficiency and flexibility allowing dynamically inserting and/or removing the partial modules to implement the partial reconfigurable FIR filters with various taps. This partial reconfigurable FIR filter design shows the configuration time improvement, good area efficiency and flexibility by using the dynamic partial reconfiguration method.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.171-174
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• 2005

Experimental measurements are reported and compared with the results of a two-dimensional fluid simulation for the investigation of the discharge characteristics regarding the change of the mixture ratio of Ne-Xe-He noble gases. The increase of Xe contents results in the increases of luminance and luminous efficiency while it also results in the increase of the breakdown voltage and the discharge time lag. The addition of He gas increases the brightness and the luminance efficiency. When Xe partial pressure is low, the luminance efficiency increases with the amount of He at the same total pressure. When Xe partial pressure is high, however, the luminance efficiency has a maximum value when the partial pressure of He is about 10% of the total pressure for a standard AC PDP cell with Xe fraction of $10{\sim}30%$.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1148-1150
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• 2003

Power conversion system must be increased switching frequency in order to achieve a small size, a light weight and a low noise. However, the switches of converter are subjected to high switching power losses and switching stresses. As a result of those, the power system brings on a low efficiency. To improved these, a large number of soft switching topologies included a resonant circuit has been prosed. But these circuits increase number of switch in circuit and complicate sequence of switching operation. In this paper, the authors propose a high power factor and high efficiency DC-DC converter using single-pulse soft switching by partial resonant switching node. The switching devices in a prosed circuit are operated with soft switching by the partial resonant method, that is, Partial Resonant Switch Mode Power Converter. The partial resonant circuit makes use of a inductor using step up and a condenser of loss-less snubber. The result is that the switching loss is very low and the efficiency of system is high. Also the proposed converter is deemed the most suitable for high power applications where the power switching devices are used. Some simulative results on computer results are included to confirm the validity of the analytical results.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.1-2
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• 2014

In this paper the partial switching PFC converter which is based on predictive control is proposed. In terms of satisfying the harmonic standard, the predictive control shows a similar performance to the conventional average current mode control PFC in the normal input condition. Moreover, the current harmonic characteristic is insensitive to the distorted input voltage. With predictive control method, novel on-line partial switching strategy is suggested in this paper. Depending on the operating condition, the partial switching PFC converter can boost its output voltage. Also when its efficiency needs to be improved, according to load condition, the partial switching can be achieved. The proposed strategy is proved by the results of FFT and the loss analysis using PSIM 9.0.