• Title, Summary, Keyword: ISI

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A Study on Hamming Codes for Mitigating ISI on the Diffusion-based Molecular Communication Channel (확산기반 분자통신 채널에서 ISI 완화를 위한 해밍 부호에 관한 연구)

  • Cheong, Ho-Young
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.14 no.1
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    • pp.1-6
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    • 2021
  • In this paper, in order to mitigate ISI(inter-symbol interference) in a diffusion-based molecular communication channel, an ISI Hamming code is proposed in which ISI characteristics are applied to a channel decoding algorithm. In order to prove the bit error rate performance of the proposed channel code, the bit error rate performance of the major channel codes applied to the molecular communication channel with ISI was compared and analyzed through simulation. From the simulation results, it can be seen that the bit error rate performance of the ISI Hamming code is the best when the number of radiated molecules is less than or equal to 1100. In addition, when the number of transmitted molecules is M=1000, the decoding method of the ISI Hamming code proposed in this paper has improved the bit error rate of approximately 5.9×10-5 compared to the Hamming code using only soft values. Compared with the ISI-mitigating channel code, which is effective for removing ISI in the molecular communication channel, the ISI Hamming code proposed in this paper is the most advantageous in a channel environment where the number of transmitted molecules is not big (M<1100). And we can see that the ISI-mitigating channel code is more advantageous when the number of transmitted molecules is large(M>1100).

Development of Intelligent Database Program for PSI/ISI Data Management of Nuclear Power Plant (Part II) (원자력발전소 PSI/ISI 데이더 관리를 위한 지능형 데이더베이스 프로그램 개발 (제 2보))

  • Park, Un-Su;Park, Ik-Keun;Um, Byong-Guk;Lee, Jong-Po;Han, Chi-Hyun
    • Journal of the Korean Society for Nondestructive Testing
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    • v.20 no.3
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    • pp.200-205
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    • 2000
  • In a previous paper, we have discussed the intelligent Windows 95-based data management program(IDPIN) which was developed for effective and efficient management of large amounts of pre-/in-service inspection(PSI/ISI) data of Kori nuclear power plants. The IDPIN program enables the prompt extraction of previously conducted PSI/ISI conditions and results so that the time-consuming data management, painstaking data processing and analysis of the past are avoided. In this study, the intelligent Windows based data management program(WS-IDPIN) has been developed as an effective data management of PSI/ISI data for the Wolsong nuclear power plants. The WS-IDPIN program includes the modules of comprehensive management and analysis of PSI/ISI results, statistical reliability assessment program of PSI/ISI results(depth and length sizing performance etc), standardization of UT report form and computerization of UT results. In addition, the program can be further developed as a unique PSI/ISI data management expert system which can be part of the PSI/ISI total support system for Korean nuclear power plants.

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ISI Estimation Using Iterative MAP for Faster-Than-Nyquist Transmission (나이퀴스트 율보다 빠른 전송 시스템에서 반복 MAP을 이용한 ISI 추정 기법)

  • Kang, Donghoon;Kim, Haeun;Park, Kyeongwon;Lee, Arim;Oh, Wangrok
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.42 no.5
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    • pp.967-974
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    • 2017
  • In this paper, we propose an inter-symbol interference (ISI) estimation scheme based on the maximum a posteriori (MAP) algorithm for faster-than-Nyquist (FTN) systems. Unfortunately, the ISI estimator based on the MAP algorithm requires relatively high computational complexity. To reduce the complexity of the MAP based ISI estimator, we propose a hybrid ISI estimation scheme based on the MAP and successive interference cancellation (SIC) algorithms. The proposed scheme not only offers good ISI estimation performances but also requires reasonably low complexity.

High Speed Low Power Decision-Feedback Equalizer Techniques (고속 저전력 결정-피드백 이퀄라이저 기술 동향)

  • Min, Woong-Ki;Kong, Bai-Sun
    • Journal of IKEEE
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    • v.20 no.3
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    • pp.285-290
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    • 2016
  • Inter-symbol interference (ISI) due to channel bandwidth limitation constrains the maximum data rate in high speed I/O. Decision feedback equalizer (DFE) is known as the most popular technique for removing ISI. To ensure fast data transmission, not only removing ISI but also raising maximum operating frequency of the circuit itself by relaxing feedback delay margin is important. For single-ended signaling, DFE should cancel out both ISI and high frequency noises. Low-power operation is as important as fast operation because required DFE elements increase as the data rate goes up. This paper surveys recent techniques for fast DFE by removing ISI and high frequency noises, and low power DFE and discusses about their merits and limitations.

Application of Risk-Informed Methods to In-Service Piping Inspection in Framatome Type Nuclear Power Plants (프라마톰형 원전의 배관 가동중검사에 리스크 정보를 활용한 기법 적용)

  • Kim, Jin-Hoi;Lee, Jeong-Seok;Yun, Eun-Sub
    • Journal of the Korean Society for Nondestructive Testing
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    • v.34 no.4
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    • pp.311-317
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    • 2014
  • The Pressurized water reactor owners group (PWROG) developed and applied a risk-informed in-service inspection (RI-ISI) program, as an alternative to the existing ASME Section XI' sampling inspection method. The RI-ISI programs enhance overall safety by focusing inspections of piping at high safety significance (HSS) locations where failure mechanisms are likely to be present. Additionally, the RI-ISI program can reduce nondestructive evaluation (NDE) exams, man-rem exposure for inspectors, and inspection time, among other benefits. The RI-ISI method of in-service piping inspection was applied to 3 units (KSNPs: Korea standard nuclear power plants) and is being deployed to the other units. In this paper, the results of RI-ISI for a Framatome type (France CPI) nuclear power plant are presented. It was concluded that application of RI-ISI to the plant could enhance and maintain plant safety, as well as provide the benefits of greater reliability.

An Equalization Method in Filtered Multitone Modulation based on the ISI Estimation (FMT 시스템의 ISI 추정치 기반 등화기법)

  • Ryu, Jung-Hun
    • Journal of Korea Multimedia Society
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    • v.12 no.9
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    • pp.1316-1322
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    • 2009
  • The multicarrier system is in the limelight for broadband wireless communications due to its spectral efficiency. Filtered multitone(FMT) system uses a filter that has several symbol periods duration. Using long-period filter causes a performance degradation because of intersymbol interference in multipath fading channels. In this paper, we propose a simple equalization method which can reduce the ISI due to the wireless channels. The proposed equalization method compensates the ISI by subtracting the estimated ISI components from the current symbol using one-tap equalizer. The performance of the proposed system is verified through theoretical analysis and simulation results show that the proposed system can mitigate the effect of ISI significantly.

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Development of Intelligent Database Program for PSI/ISI Data Management of Nuclear Power Plant (원자력발전소 PSI/ISI 데이터 관리를 위한 지능형 데이터 베이스 프로그램 개발)

  • Park, Un-Su;Park, Ik-Keun;Um, Byong-Guk;Park, Yun-Won;Kang, Suk-Chul
    • Journal of the Korean Society for Nondestructive Testing
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    • v.18 no.5
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    • pp.389-397
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    • 1998
  • For an effective and efficient management of large amounts of preservice/inservice inspection(PSI/ISI) data in nuclear power plants, an intellegent Windows 95-based data management program was developed. This program enables the prompt extraction of previously conducted PSI/ISI conditions and results so that the time-consuming data management, painstaking data processing and analysis in the past are avoided. The program extracts, and the associated remedies. Furthermore, additional inspection data and comments can be easily added or deleted for subsequent PSI/ISI operation. Although the initial version of the program was applied to Kori nuclear power plant, this program can be equally applied to other nuclear power plant. And also this program can be used to offer the fundamental data for application of evaluation data related to fracture mechanics analysis(FMA), probabilistic reliability assessment(PRA) of PSI/ISI results, performance demonstration initiative(PDI) and risk-informed ISI based on probability of detection(POD) information of ultrasonic examination. Besides, the program can be further developed as a unique PSI/ISI data management expert system that can be apart of PSI/ISI data management expert system that can be a part of PSI/ISI Total Support System(TSS) for Korean nuclear power plants.

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Development of ISI UT Auto Flaw Evaluation and Acceptance Module of Nuclear Power Plants (원전 ISI UT 자동 결함평가 및 판정 모듈 개발)

  • Park, Ik-Keun;Park, Un-Su;Kim, Hyun-Mook;Kim, Chung-Seok;Um, Byong-Guk;Lee, Jong-Po
    • Proceedings of the KSME Conference
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    • pp.212-218
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    • 2000
  • The importance and role of pre-/in-service inspection(PSI/ISI) for nuclear power plant(NPP) components are intimately related to plant design, safety, reliability, operation, etc. In this paper, for an effective and efficient management of large amounts of PSI/ISI data in NPPs, an intelligent database program(WS-IDPIN) for PSI/ISI data management of NPP was developed. WS-IDPIN program enables the prompt extraction of previously conducted PSI/ISI conditions and results so that the time-consuming data management, painstaking data processing and analysis in the past are avoided. Furthermore, development of ISI UT auto flaw evaluation and acceptance module based on ASME Code Sec. XI were presented. This module can be used for any angle beam examination from flat plate to spherical shapes as selected by the proper azimuthal angle. This program can be further developed as a unique PSI/ISI data management expert system.

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The Sleep Characteristics of Chronic Schizophrenia Patients with Insomnia in Community-based Mental Health Services (지역사회 정신보건 서비스를 이용하는 불면증을 동반한 만성 조현병 환자의 수면의 특징)

  • Hwang, Dong-Ki;Nam, Min;Lee, Yu-Jin G.
    • Sleep Medicine and Psychophysiology
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    • v.24 no.2
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    • pp.97-105
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    • 2017
  • Objectives: To evaluate sleep characteristics and factors associated with sleep disturbance in schizophrenia patients with concurrent active psychotic symptoms and insomnia. Methods: Schizophrenia patients with insomnia and active psychotic symptoms (n = 63) were recruited from community-based mental rehabilitative facilities. Sleep scales such as the Korean version of the Insomnia Severity Index (ISI-K) and the Korean Version of the Pittsburgh Sleep Quality Index (PSQI-K) were evaluated and those with ISI-K >15 were included in the study. Psychotic, anxiety and depressive symptoms were rated with the Brief Psychotic Rating Scale (BPRS), the Korean Version of the Anxiety Sensitivity Index (K-ASI), and the Korean Version of the Beck Depression Inventory-I (K-BDI), respectively. Pearson correlation analyses were performed between the sociodemographic data, ISI-K and PSQI-K. Multiple linear regression analysis was conducted to investigate the factors which affected the ISI-K and PSQI-K. Results: The mean ISI-K and PSQI-K scores were $18.1{\pm}2.6$ and $12.0{\pm}2.2$, respectively. Pearson correlation analysis showed a negative correlation between age of onset and ISI-K score and positive correlations between BRPS and PSQI-K scores and between K-ASI and both ISI-K and PSQI-K scores. Multiple regression analyses for both ISI-K and PSQI-K with K-ASI, age of onset, and BPRS as covariates revealed K-ASI as the only significant remaining factor. Conclusion: Our study suggests that anxiety symptoms are associated with insomnia symptoms in schizophrenia patients regardless of depressive or psychotic symptoms.

Parameter Derivation for Reducing ISI in 2-Dimensional Faster-than-Nyquist Transmission (나이퀴스트율보다 빠른 전송 시스템에서 ISI 감소를 위한 변수 도출 방법)

  • Kang, Donghoon;Kim, Haeun;Park, Kyeongwon;Oh, Wangrok
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.10
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    • pp.1147-1154
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    • 2016
  • A faster-than-Nyquist (FTN) transmission scheme has been attracting great attention as a spectral efficient transmission scheme. In the FTN transmission scheme, modulated symbols are transmitted at a rate higher than Nyquist rate and thus, a performance loss due to the inter-symbol interference (ISI) is unavoidable. To minimize the performance loss in the FTN transmission scheme, parameters should be carefully optimized. Unfortunately, simulation-based parameter optimization requires significant amount of time and computing power, especially for 2-dimensional FTN systems. In this paper, we propose a 2-dimensional FTN transmission scheme using the optimized parameters based on numerical analysis and simulation results on the ISI. Compared with the conventional Nyquist system, the proposed 2-dimensional FTN transmission scheme not only offers virtually identical bit error performance but also offers higher spectral efficiency.