• The KIPS Transactions:PartC
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• v.13C no.3 s.106
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• pp.369-374
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• 2006

This paper related with the performance improvement of adaptive equalizer that is a based on the tricepstrum eqalization algorithm by using the received signal. Adaptive equalizer used for the improvement of communication performance, like as high speed, maintain of synchronization, BER, at the receive side in the environment of communication channel of the presence of the aditive noise, phase distortion and frequency selective fading, mainly. It's characteristics are nearly same as the inverse characterstics of the communication channel. In this paper, the TEA algorithm using the HOS and the 16-QAM which is 2-dimensional signaling method for being considered signal was used. For the precoding of 16-QAM singnal in the assignment of the signal costellation, Gray code was used, and the improvement of performance was gained by computer simulation in the residual intersymbol interence and mean squared error which is representive measurement of adaptive equalizer.

• The Journal of the Acoustical Society of Korea
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• v.38 no.6
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• pp.678-686
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• 2019

Underwater communication performance is degraded by the influence of Inter-Symbol Interference (ISI) due to multipath. Passive time reversal processing is the most effective technique for mitigating multipath, and the diversity combining method can be used to improve its performance. This paper analyzed communication performance using the beam diversity combining method, which combines signals obtained through the beam steering to various angles. Directions of arrival were estimated through the beam-time migration, which, in turn, was estimated from probe signals received by a vertical line array. The performance was analyzed based on the number and type of combinations among the estimated angles. In this paper, the data obtained from the Biomimetic Long range Acoustic Communications 2018 (BLAC18) experiment, which was conducted in the East sea, ~50 km east of Pohang, in October 2018, were used for the analysis. The output Signal to Noise Ratio (SNR) was used as communication indicators.

• Nuclear Engineering and Technology
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• v.36 no.1
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• pp.112-120
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• 2004

The purpose of this paper is to analyze the piping failure frequency for the main feedwater system in domestic nuclear power plants(NPPs) for the application to an in-service inspection(ISI), leak before break(LBB) concept, aging management program(AMP), and probabilistic safety analysis(PSA). First, a database was developed for piping failure events in domestic NPPs, and 23 domestic piping failure events were collected. Among the 23 events, 12 locations of wall thinning due to flow accelerated corrosion(FAC) were identified in the main feedwater system in 4 domestic WH 3-loop NPPs. Two types of the piping failure frequency such as the damage frequency and rupture frequency were considered in this study. The damage frequency was calculated from both the plant population data and damage(s) including crack, wall thinning, leak, and/or rupture, while the rupture frequency was estimated by using both the well-known Jeffreys method and a new method considering the degradation due to FAC. The results showed that the damage frequencies based on the number of the base metal piping susceptible to FAC ranged from $1.26{\times}10^{-3}/cr.yr\;to\;3.91{\times}10^{-3}/cr.yr$ for the main feedwater system of domestic WH 3-loop NPPs. The rupture frequencies obtained from the Jeffreys method for the main feedwater system were $1.01{\times}10^{-2}/cr.yr\;and\;4.54{\times}10^{-3}/cr.yr$ for the domestic WH 3-loop NPPs and all the other domestic PWR NPPs respectively, while those from the new method considering the degradation were higher than those from the Jeffreys method by about an order of one.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.477-480
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• 2005

CMA-DD is proposed to improve the steady-state performance of CMA and its performance is depending on switching time between two modes of operation. Castro et al. who proposed a concurrent equalizer for solving problem of CMA-DD, which reduced the sensibility of switching time. However, concurrent algorithm has a problem that it keeps working after convergence. In this paper, we propose concurrent MCMA-DD equalizer combined modified CMA(MCMA) and DD mode for making better concurrent algorithm. The proposed equalizer is better than previous algorithm in convergence speed and steady-state performance. Also, the proposed algorithm decides optimum switching time using residual ISI of the equalizer output.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.8
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• pp.18-24
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• 2017

The process of transmitting messages through a medium with a limited bandwidth or channel dispersion inevitably involves signal distortion and noise influxes, resulting in the degradation of transmission quality due to the inter-symbol interference and additional noise, which increases the error rate of the received symbols. The main role of the equalizer is to remove the channel distortion and noise from the received signal to recover the transmitted messages. A number of studies on the equalizer composed of a combination of linear filter and error control coding have shown that they played a key role in enhancing the transmission efficiency, which is essential for digital communication. This paper proposes a new algorithm to correct the residual symbol errors in the message signal. In general, equalizer performance improvement algorithms were developed to improve the initial convergence speed or steady-state error. In this paper, however, the equalizer input signal was reconstructed using the equalizer decision symbols and the channel estimates to directly correct the decision errors by analyzing the statistical characteristics of the difference signal between the actual received signal and the reconstructed signal.

• The Transactions of the Korea Information Processing Society
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• v.4 no.10
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• pp.2562-2570
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• 1997

This paper deals with the design and performance of the adaptive equalizer using high order statistics in order to improve the transmission characteristics of multipath fading channel. The multipath propagational phenomenon occurred in digital radio transmission causes the distortion and ISI of receiving signal. These are main reasons to increase the bit error rate and degrade the performance of receivers. In this paper, the adaptive equalization algorithm using high order statistics of received signal is used instead of CMA algorithm, Bussgang and Godard which are known widely. The performance of this algorithm (residualisi, recovered constellation, calculation) is presented varing SNR. As the result of the computer simulation, equalizer algorithm using high order statistics is better than CMA in the range of low SNR, $10{\sim}20dB$. Therefore, considering the actual communication systems which use the range of $14{\sim}20$ SNR, the adaptive equalizer using high order statistics can be used in the real multipath fading environment.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1552-1553
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• 2007

2001년 1월 빌 클린턴 미국 전 대통령의 국가나노기술전략 (National Nanotechnology Initiative) 발표 이후 현재 전세계 50여개 국가에서 국가핵심전략 연구개발사업의 하나로 나노기술을 선정하고 집중투자하고 있다. 이러한 정책 및 예산지원으로 인해 정부연구개발투자의 효율화를 위한 연구성과의 체계적인 평가가 중요하게 되었으며, 나노기술 연구개발 활동의 연구결과는 과학기술 생산성이나 연구결과물 즉 논문 등의 출판을 통한 확산이나 인용분석 등에 기초한 양적 평가지표를 이용해 측정하는 서지적 방법에 의해 평가되고 있다. 나노기술 연구활동 및 실적에 대한 객관적 평가는 과학기술 정책 입안과 의사결정 과정에서 중요한 역할을 하며 나노기술 분야의 연구활동을 평가하기 위한 중요한 지표가 될 수 있는 것이 연구논문이다. 이에 본 연구에서는 미국의 민간학술정보전문기관인 ISI(Institute for Scientific Information)에서 구축하였으며 주요과학기술문헌 인용색인정보를 수록한 SCIE 데이터베이스를 활용하여 우리나라의 나노기술관련 논문신장율, 세계점유율 및 국가별 비교분석을 수행함으로써 국내 나노기술 연구개발 수준 및 성과분석을 위한 기초 자료를 제공하고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.3132-3138
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• 2014

In many communication systems, intersymbol interference, DC and impulsive noise are hard-to-solve problems. For the purpose of cancelling such interferences, the concept of lagged cross-correlation of probability has been used for blind equalization. However, this algorithm has a large burden of computation. In this paper, a recursive method of the algorithm based on the lagged probability correlation is proposed. The summation operation in the calculation of gradient of the cost is transformed into a recursive gradient calculation. The recursive method shows to reduce the high computational complexity of the algorithm from O(NM) to O(M) for M symbols and N block data having advantages in implementation while keeping the robustness against those interferences. From the results of the simulation, the proposed method yields the same learning performance with reduced computation complexity.

• Journal of Advanced Navigation Technology
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• v.8 no.2
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• pp.120-128
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• 2004

Although conventional OFDM/QAM modulation scheme using guard interval is robust to channel induced ISI (Inter-Symbol Interference) in time-domain, it is very sensitive to ICI (Inter-Carrier Interference) due to doppler effect in frequency domain. OFDM/OQAM-IOTA modulation scheme utilizes IOTA (Isotropic Orthogonal Transform Algorithm) filter that has orthogonality in time and frequency domain so that it is robust to delay spread and doppler effect. OFDM/OQAM-IOTA system can increase bandwidth effeciency since it does not use guard interval. In this paper, we show the structure of OFDM/OQAM-IOTA and perfect channel estimation scheme for OFDM/OQAM-IOTA system. We also compare OFDM/OQAM-IOTA system and OFDM/QAM system in AWGN and 1-path Rayleigh fading channel. Simulation results show that OFDM/OQAM system outperforms OFDM/QAM system.

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.5
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• pp.27-39
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• 2019

This study is a case study of KEB HanaBank's information system integration, which has achieved outstanding results based on successful M & A. As of the end of 2018, KEB HanaBank is one of the domestic commercial banks that showed 896 domestic and overseas branches, 12,881 employees, total assets of 326 trillion won, and net income of 1.9 trillion won. The purpose of this study is to provide implications through KEB Hana Bank's unique case and strategy for information system integration since M & A. To accomplish this, KEB HanaBank's information system integration related resource status, strategy, and performance are searched using various sources, and existing researches on resource dependency theory and entrepreneurial bricolage are reviewed. In the post merger integration process, organizations need to understand the status of their resources in terms of resource constraint theory in order to succeed in the information system integration. In resource constraints, for successful computational integration, a strategy based on entrepreneurial bricolage will be needed.