• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.89-92
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• 2001

In this paper, adaptive multi-stage parallel interference cancellation (PIC) receiver is considered for a multi-rate DS-CDMA system. In each stage of the adaptive multi-stage PIC receiver, multiple access interference (MAI) estimates are obtained using the sub-bit estimates from the Previous stage and the adaptive weights for the sub-bit estimates. The adaptive weights are obtained by minimizing the mean squared error between the received signal and its estimate through a least mean square (LMS) algorithm. It is shown that the adaptive multi- stage PIC receiver achieves smaller BER than the matched filter receiver, multi-stage PIC receiver, and multi-stage partial PIC receiver for the multi-rate DS-CDMA system in a Rayleigh fading channel.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.9-12
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• 2001

In this paper, the natural space-time coding is applied for a DS-CDMA system with multiple transmit/receive antennas in a Rayleigh fading channel. With difference of arrival times from transmit antennas a modified maximum likelihood (ML) decoding algorithm is proposed for the space-time coded DS-CDMA system. The proposed decoding algorithm performs ML decoding over the transition of two consecutive branches by using a modified branch metric with the partial autocorrelation. By simulation, it is shown that the proposed decoding algorithm achieves significant performance improvement over the ML decoding algorithm without the modified branch metric.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.9
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• pp.863-871
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• 2004

In this paper, we propose a subspace channel estimation technique for DS/CDMA DMB down link system, which can obtain reduction in numerical complexity by using of matched filtering outputs. The complexity reduction is considerable when the channel length is small and the system is moderately loaded. Previously proposed subspace-based blind channel estimation algorithm suffer from high numerical complexity for systems with large spreading gains. Although the proposed algerian suffers a slight performance loss, it becomes negligible for large observation length. Performance is evaluated through simulations and the derivation of the analytical MSE.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.399-401
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• 1999

최근 컴퓨터 네트워크를 통한 화상회의, 화상전화 VOD 등과 같은 응용 프로그램들이 실시간 통신을 필요로 한다. 이러한 실시간 통신에 적합한 ATM은 유연한 통신 서비스와 높은 질의 서비스를 제공함으로서 차세대 통신 네트웍으로 기대가 되고 있다. ATM 네트웍 막에서 실시간 통신을 하기 위해서는 실시간 데이터들이 지연한계를 만족해야 한다. 만약 이러한 지연한계를 만족시키지 못할 경우에는 서비스의 질이 떨어지거나 아니면 데이터가 아예 필요가 없어지게 된다. 이미 실시간 통신을 하기 위해 Virtual Clock, Stop-and-Go, EDF 등에 많은 패킷 스위치 스케줄링 정책들이 개발 되어져 왔다. 그러나 이러한 스위치 스케줄링 정책들은 대부분 그 방법의 복잡성 때문에 실제로 ATM 상에서 적용시키기가 힘들다. 본 논문에서는 ATM 네트웍 망에서 화상 통신을 하기 위해 적합한 새로운 스위치 모델인 TCRM-DS를 제시한다. TCRM-DS는 기존의 TCRM 모델의 장점인 단순성과 효율성을 그대로 유지하면서 TCRM 모델의 단점인 비 실시간 데이터에 대한 비효율적 처리를 개선한 것이다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.10
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• pp.4606-4611
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• 2011

In this paper, it is reviewed vulnerability of security in DS-MAC communication protocol of sensor network, and analyzed in the respect of security effectiveness, which is consumed at each stage of communication procedure in according to vulnerability of denial of service and modification attack. In this paper, we present about the respect of security effectiveness of transmission and reception in case of operation mode with or without authentication scheme between sensor node.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.35-42
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• 1996

In this Paper, optical absorption were performed on LB films of binary mixtures of three kinds of merocranine dyes DO, DS, and 6Me-BS, where DS and 6Me-DS form J-like aggregates but not DO in single component films. The observed optical absorption spectra of mixed films were markedly defendent on the combination of dyes. [6Me-DS]$\sub$1-x/[DOl]$\sub$x/ LB films show a sharp red shifted J-like band peak in the whole concentration range. We found the formation of f aggregates in a mixed merocyanine dyes containing a non J-aggregate forming dye DO, in a single component case. Farther investigations on the present and other mixed-dye films will be needed to clarify these points.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.9A
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• pp.1058-1066
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• 2004

This paper proposes the acquisition system using the multiple antennas in DS-CDMA system. The conventional acquisition schemes using multiple antennas are the methods to utilize the multi-antenna combining and the fixed multi-beam forming of a serial acquisition. Then, this paper proposes the hybrid acquisition scheme using the fixed multi-beam forming. The numerical results show the performance comparison of two acquisition schemes in terms of the acquisition time ill the multipath Rayleigh fading channel.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.9A
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• pp.1039-1047
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• 2004

In this paper, we propose a new channel estimation technique for long code DS-CDMA DMB down link system which estimate the channel response based on the signal space vector only, unlike the most conventional sub-space method relying on the orthogonal property of noise space vectors to the signal space vector. Because of this property of the proposed method, very optimum covariance matrix in its dimension can be used in subspace analysis channel estimation technique otherwise it is likely too large to be implemented practically.

• Journal of Food Hygiene and Safety
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• v.14 no.1
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• pp.84-89
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• 1999

Octenylscuccinated corn starches prepared by reaction of corn starch with 1-octenylsuccinic anhydride(OSAn) and their degree of substitution (DS), reaction efficiency(RE), residual octenylsuccinic acid (OSA), and physicochemical properties were compared with those of the native corn starch. DS increased with increase of OSAn and RE was much nearly the same regardless of increased of OSAn. The content of residual of residual OSA was significantly lower than that of regulation of food additives. And as washing frequency of dispersion of the reactant was increased, the content of residual OSA of octenylsuccinated starch was decreased. Raid Visco-Analyzer initial pasting temperature and setback of octenylsuccinated starches decreased whereas peak viscosity and breakdown increased. When DS of octenylsuccinated starches increased, temperature of initial gelatinization of octenylscuccinated starches drastically decreased. The octenylsuccinated starches also formed clearer pastes. The solubility was much nearly the same regardless of increase of DS at 7$0^{\circ}C$ but the swelling power increased 1.2~1.7 times higher than that of native corn starch at 7$0^{\circ}C$. The water binding capacity of octenylsuccinated starches also decreased.

• Applied Biological Chemistry
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• v.34 no.2
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• pp.86-93
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• 1991

cis-Diamminedichloroplatinum(II)(CDDP), an antitumor drug, did not generate crosslink between bluetongue virus (BTV) capsid protein at moderate concentration. Cesium chloride density gradient centrifugation study revealed that protein-RNA crosslink was not detectable in CDDP treated BTV. CDDP treated BTV ds RNA showed remarkable change in the migration pattern in polyacrylamide gel electrophoresis. These results suggest that the reduction of BTV core associated transcriptase activity is most likely by the CDDP adduction to the genomic ds RNA rather than by the protein-RNA crosslink and/or protein-protein cross-link.