• Title/Summary/Keyword: ISI

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A study on mitigation of ISI using decision-feedback equalizer in digital holographic optical memory system (디지털 홀로그래픽 광메모리 시스템에서 decision-feedback equalizer를 이용한 ISI 완화에 관한 연구)

  • 최안식;백운식
    • Proceedings of the Optical Society of Korea Conference
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    • 2000.02a
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    • pp.56-57
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    • 2000
  • In this paper, DFE with feedforward section(FDFE) is used to mitigate ISI and improve BER generated in the course of storage and retrieval of high-density 2-dimensional data in digital holographic memory system. From the result of experiment, BER performance of DFE with feedforward section is improved about 37% than binary-decision course by direct thresholding.

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Experience in Ultrasonic Flaw Estimation and its Excavation on the Weldments of Nuclear Pressure Vessels (원전 압력용기 용접부 초음파탐상, 결함크기 평가 및 결함 수리 경험)

  • Lee, J.P.;Park, D.Y.;Lim, H.T.;Kim, B.C.;Joo, Y.S.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.11 no.1
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    • pp.52-60
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    • 1991
  • The importance and role of preservice and inservice inspection(PSI/ISI) for nuclear power plant components are intimately related to plant design, safety, reliability and operation etc.. The Korea Atomic Energy Research Institute(KAERI) has been performing PSI/ISI in Korea since the PSI of Kori nuclear power plant, unit 1 had been performed in 1977. KAERI has localized PSI/ISI technology and has done much experience in ultrasonic flaw detection, evaluation and its excavation on the weldments of large pressure vessels. The results of flaw estimation using ultrasonic examination are compared with the actual flaw sizes revealed by field excavation. KAERI's experience regarding PSI/ISI was described and some discussions were added.

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Performance Evaluation of Adaptive Modulation System with STTD (STTD 기법을 적용한 적응변조시스템의 성능 평가)

  • 강도욱;강희조
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.7 no.3
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    • pp.411-416
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    • 2003
  • In this paper, We analysed performance of adaptive modulation system with STTD. Transmission error of system is increased by ISI according to delay wave in wireless channel environment. Therefore, We analysed performance that it is applied adaptive modulation system with STTD to reduce ISI's effect. As a results, Data transmission of high speedㆍhigh quality could know possible by applying adaptive modulation system with STTD. Because of selected high modulation mode in low SNR.

Development of Web based PSI/ISI Information Management System for Virtual Nuclear Power Plant (Web 기반의 가상원전 PSI/ISI 정보관리 시스템 개발)

  • Shin, Jin-Ho;Lee, Bong-Jae;Song, Jae-Ju;Jang, Mun-Jong
    • Proceedings of the KIEE Conference
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    • 2002.07d
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    • pp.2761-2763
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    • 2002
  • 원자력발전소에서는 건설완료 단계에서 기기, 배관 및 각종 지지구조물에 대하여 PSI(Pre-Service Inspection)를 실시하여 시공된 설비의 건전성을 점검하고, 운영중에는 주기적으로 시간의 경과에 따른 취약화 정도를 비과괴검사로 감시 및 평가하는 ISI (In-Service Inspection)를 실시하여 안전성 관련 설비의 건전성을 점검하고 있다. 이 과정에서 방대한 양의 검사데이터가 생산되며 원전 가동년수가 증가함에 따라 검사자원을 체계적으로 관리하고 자동화 할 수 있는 시스템 개발이 필요하게 되었다. 본 논문에서는 PSI/ISI 검사결과 정보관리를 비롯하여 검사 기초자료 관리 및 검사계획 수립, 파괴역학 분식 기능 등을 포함한 Web 기반의 Application 개발 사례를 소개한다. 또한 가상현실 기법을 적용하여 기존의 2차원적 DB 운영을 3차원 가상공간에서 운영할 수 있는 'Touch & Tell' 기법을 개발하고 그 구현방법을 제시한다.

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Adaptive Techniques for Joint Optimization of XTC and DFE Loop Gain in High-Speed I/O

  • Oh, Taehyoun;Harjani, Ramesh
    • ETRI Journal
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    • v.37 no.5
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    • pp.906-916
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    • 2015
  • High-speed I/O channels require adaptive techniques to optimize the settings for filter tap weights at decision feedback equalization (DFE) read channels to compensate for channel inter-symbol interference (ISI) and crosstalk from multiple adjacent channels. Both ISI and crosstalk tend to vary with channel length, process, and temperature variations. Individually optimizing parameters such as those just mentioned leads to suboptimal solutions. We propose a joint optimization technique for crosstalk cancellation (XTC) at DFE to compensate for both ISI and XTC in high-speed I/O channels. The technique is used to compensate for between 15.7 dB and 19.7 dB of channel loss combined with a variety of crosstalk strengths from $60mV_{p-p}$ to $180mV_{p-p}$ adaptively, where the transmit non-return-to-zero signal amplitude is a constant $500mV_{p-p}$.

Enhanced Inter-Symbol Interference Cancellation Scheme for Diffusion Based Molecular Communication using Maximum Likelihood Estimation

  • Raut, Prachi;Sarwade, Nisha
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.10 no.10
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    • pp.5035-5048
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    • 2016
  • Nano scale networks are futuristic networks deemed as enablers for the Internet of Nano Things, Body area nano networks, target tracking, anomaly/ abnormality detection at molecular level and neuronal therapy / drug delivery applications. Molecular communication is considered the most compatible communication technology for nano devices. However, connectivity in such networks is very low due to inter-symbol interference (ISI). Few research papers have addressed the issue of ISI mitigation in molecular communication. However, many of these methods are not adaptive to dynamic environmental conditions. This paper presents an enhancement over original Memory-1 ISI cancellation scheme using maximum likelihood estimation of a channel parameter (λ) to make it adaptable to variable channel conditions. Results of the Monte Carlo simulation show that, the connectivity (Pconn) improves by 28% for given simulation parameters and environmental conditions by using enhanced Memory-1 cancellation method. Moreover, this ISI mitigation method allows reduction in symbol time (Ts) up to 50 seconds i.e. an improvement of 75% is achieved.