• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.2
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• pp.251-256
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• 2001

An error probability analysis is performed far a hybrid DS/SFH spread-spectrum system using minimum shift keying(MSK) modulation. The channel is assumed to be a Rayleigh fading channel with partial-band noise interference. Expressions are derived for the bit error rate(BER) in the context of Rician and Rayleigh fading channels, as a function of the average signal-to-noise ratio(SNR) $E_b/N_0$, the average signal-to- interference ratio(SJR) $E_b/N_J$, and channel parameters. As a result, in the fading channel with large Rician factor, K, which denotes the ratio of power of the direct and the diffused components, the partial-band interference is the worst case. On the other hand, in Rayleigh fading channel(K=0), the full-band interference($\rho$=1) brings the system to the worst case. Performance comparisons among various channels show that the factor K has much large effect on overall performance. For example, in conditions of $\rho$=0.1 and BER=$10^-2$, the system in Rician channel with K=10 requires more 1.9 dB SNR than that in AWGN channel, whereas it is less 5 dB SNR than that in the Rayleigh channel with K=0.

• Biomolecules & Therapeutics
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• v.18 no.4
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• pp.448-453
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• 2010

Drug-induced long QT syndrome is known to be associated with the onset of torsades de pointes (TdP), resulting in a fatal ventricular arrhythmia. QT interval prolongation can result from blocking the human ether-a-go-go-related gene (hERG) channel, which is important for the repolarization of cardiac action potential. Nicardipine, a Ca-channel blocker and antihypertensive agent, has been reported to increase the risk of occasional serious ventricular arrhythmias. We studied the effects of nicardipine on hERG $K^+$ channels expressed in HEK293 cells and Xenopus oocytes. The cardiac electrophysiological effect of nicardipine was also investigated in this study. Our results revealed that nicardipine dose-dependently decreased the tail current of the hERG channel expressed in HEK293 cells with an $IC_{50}$ of 0.43 ${\mu}M$. On the other hand, nicardipine did not affect hERG channel trafficking. Taken together, nicardipine inhibits the hERG channel by the mechanism of short-term channel blocking. Two S6 domain mutations, Y652A and F656A, partially attenuated (Y652A) or abolished (F656A) the hERG current blockade, suggesting that nicardipine blocks the hERG channel at the pore of the channel.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.207-210
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• 1996

This paper describes the analysis of the operation of the switched snubber in order to depress the surge voltage in the MOS-FET inverter. In this paper, the N-channel MOS-FET which operates faster than the P-channel MOS-FET was used for the inverter circuit. So, the inverter and switched snubber can operate at high-frequency in the order of MHz. The cause of generating the surge voltage in the high frequency inverter has been cleared, and then how to depress the surge voltage using the switched snubber consisting of an N-channel MOS-FET has been given. Furthermore, described is the power loss within the switched snubber which is made of an N-channel MOS-FET. The inverter having the N-channel MOS-FET used as a switched snubber can drive such a low impedance load such as mega-sonic transducer for a mega-sonic studied cleaner sufficiently.

• Proceedings of the KSRS Conference
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• v.2
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• pp.800-803
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• 2006

The Space-borne electro-optical camera system, like KOMPSAT has panchromatic redundant image channel as well as primary channel in order to increase reliability of satellite system. In most case redundant channel never been used during the whole mission period. Staggered array configuration using redundant image channel and new operation mode proposed which operates primary and redundant channel simultaneously. Without new hardware design, fast electronics and system complexity, we can get 1.414 times more fine GSD image of original system and aliasing effect which corrupt high frequency information of image can be minimized. To get the more efficiency from staggered array configuration, we introduce masked pixel CCD.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.337-340
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• 2009

In general, channel information of received DTV signal analyzed based on symbol timing clock with only In-phase information in DTV receiver. This paper presents technical requirements of channel analysis system for DTV reception signal. In order to meet such requirements and measure more accurate magnitude and phase of channel information, compensation method for the quadrature information from measured in-phase data is proposed. The proposed channel analysis system is implemented with a commercial DTV chipset and provides fast data analysis with good connectivity with field test vehicles. Computer simulation and laboratory test results are provided to figure out the performance of the proposed channel analysis system for DTV signal.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06d
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• pp.325-327
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• 2011

With increasing competition of the radio spectrum, co-channel interference(CCI) is becoming the dominant interference and may seriously degrade the communication performance of wireless stations. Co-channel interference, when not minimized, increases the probability of packet collisions which cause diminished system capacity. The work presented in this paper investigates the effect of co-channel interference, which is studied in a co-channel interference scenario. To minimize the co-channel interference, a new MAC protocol is proposed in this paper.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2559-2561
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• 2002

This paper presents a systematic method of probing channel characteristics and communication reliabilities of home PLC (power line communication) network applied to the Internet accessed control of home appliances. The effects of the three performance deterioating factors, i.e., additive noise, channel attenuation, and intersymbol interference, can be systematically measured by applying the channel probing waveform in the frequency range from 100kHz to 450kHz. The agreement between the derived probability of bit error and the measured probability of bit error supports the validity of the proposed approach of probing home power line channel characteristics. The experimental results performed with the constructed test-bed applying the proposed channel probing method also support the feasibility of commercially deploying the PLC modem installed home appliances and their services for the Internet accessed home automation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.52-55
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• 2004

In this paper, we examined channel charge which occurs in electron accumulation after electron velocity saturation. Generally, short gate GaAs MESFET show, saturated electron velocity leading to current salutation. When electron velocity is saturated, deletion layer is stil open channel and it play a key role in deciding saturation current mode we proposed channel charge model in channel after electron velocity saturation.

• Journal of the Optical Society of Korea
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• v.7 no.2
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• pp.97-101
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• 2003

The transmission characteristics of multi-channel long period fiber gratings (LPFGs) in terms of the physical parameters like the separation distance, grating length and number of gratings will be discussed. Their transmission characteristics such as channel spacing, number of channels, loss peak depth, and channel bandwidth can be easily controlled by physical parameters. Based on the experimental results, their applications to optical multiwavelength Raman lasers and optical sensors will be investigated. A multiwavelength Raman fiber ring laser with 9 WDM channels with 100 ㎓ spacing and 19 channels with 50 ㎓ spacing using tunable multi-channel LPFGs will be experimentally demonstrated. The fiber-optic sensing applications with high resolution and sensitivity based on multi-channel LPFGs will be also presented.

• Journal of the Korea Society of Computer and Information
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• v.23 no.8
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• pp.51-57
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• 2018

In this paper, we investigate the impact of channel estimation error on the D2D power control algorithm. In the previous work, D2D power control algorithm has been proposed under the assumption that the channel between the transmitter and the corresponding receiver is perfectly estimated. In reality, the channel estimation error is more often the case. The first question is that the power control algorithm designed for perfect channel estimation is still valid under the channel estimation error environment ? The second question is, if it is not valid, what could be the possible remedy for the channel estimation error ? In this paper, to answer the first question, we investigate the impact of the channel estimation error on the power control algorithm. We first review the D2D power control algorithm designed for perfect channel estimation. Then, we model the channel estimation error. Finally, we summarize the main results observed from the analysis of the simulation.