• 정보보호학회논문지
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• 제34권2호
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• pp.157-166
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• 2024

LWE(learning with errors) 문제 기반의 공개키 암호는 기법 설계 및 파라미터 설정에 따라 복호화 실패율이 주어지는데, 높은 복호화 실패율은 실용성의 저하를 불러올뿐만 아니라 기법에 대한 공격으로 이어질 수 있음이 밝혀진 바 있다[1]. 따라서, KpqC 1차 라운드에 제안된 Ring-LWE 기반 KEM 기법인 TiGER[2]는 오류 보정 코드 (error correction code) Xef와 D2 인코딩 방법을 사용함으로써 복호화 실패율을 낮추고자 하였다. 그런데, Ring-LWE 문제에 기반한 암호화 기법 중 오류 보정 코드를 사용하는 기법의 경우 흔히 가정하는 각 비트 오류의 독립성이 성립하지 않음이 알려진 바 있다[3]. TiGER의 복호화 실패율 계산은 이를 고려하지 않은바, 본 논문에서는 오류 의존성을 고려하여 복호화 실패율을 다시 계산한다. 또한, TiGER(v2.0)의 비트 오류가 잘못 계산되었음을 발견하여 올바른 비트 오류 계산 식과 그에 따라 새로 계산한 복호화 실패율을 제시한다.

• Journal of Communications and Networks
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• 제12권6호
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• pp.616-623
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• 2010

In this paper, exact closed-form expressions for outage probability and bit error probability (BEP) are presented for multi-hop decode-and-forward (DF) relaying schemes in conjunction with cooperative diversity, in which selection combining technique is employed at each node. We have shown that the proposed protocol offers remarkable diversity advantage over direct transmission as well as the conventional DF relaying schemes with the same combining technique. We then investigate the system performance when different diversity schemes are employed. It has been observed that the system performance loss due to selection combining relative to maximal ratio combining is not significant. Simulations are performed to confirm our theoretical analysis.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권12호
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• pp.696-701
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• 2003

This paper presents a systematic method of probing channel characteristics and communication reliabilities of home 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. Probability of bit error is derived with the probed channel parameters of the signal attenuation, noise and signal-to-interference ratio read in the frequency domain. 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.

• 한국정보통신학회논문지
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• 제10권3호
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• pp.579-585
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• 2006

본 논문에서는 스펙트럼 분할된 WDM시스템의 성능해석시, 광전치 증폭기를 사용하여 일반적인 핀(PIN) 다이오드를 채용한 수신기를 통해 얻을 수 있는 수신감도를 개선하는 방법에 대해 해석하였다. 또한 온-오프키잉(OOK: On Off Keying)과 주파수 천이키잉(FSK: Frequency Shift Keying) 전송을 이용하여 표준에러 확률을 유지하기 위해 필요로 하는 비트당 광자의 수를 계산한 후 수신기에서 광신호와 전기신호의 다양한 대역폭 비가 변화하는 경우에 대하여 위의 값을 다시 도출함으로써 수신감도를 해석하였다.

• 한국통신학회논문지
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• 제34권7A호
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• pp.523-529
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• 2009

This paper provides closed form expressions for the evaluation of the end-to-end outage probability, symbol error rate, bit error rate and average capacity of the partial-based Decode-and-Forward (DF) relay selection scheme with an arbitrary number of relays. In a comparison with the performance of systems that exploit Amplify-and-Forward (AF), it can be seen that the performance of our proposed protocol converges to that of partial-based AF relay selection in high SNR regime. We also perform Monte-Carlo simulations to validate the analysis.

• 정보처리학회논문지C
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• 제11C권1호
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• pp.109-114
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• 2004

본 논문에서는 통신 시스템에서 발생하는 에러를 정정 및 검출하기 위한 새로운 부호와 그 복호 방식을 제안하였다. 데이터 0의 런 길이를 제한하고 데이터 1의 최소 밀도를 증가시키기 위하여 (15, 7) BCH 부호를 변형하였으며 전체 패리티 비트를 추가하였다. 제안된 부호는 (16, 7) 블록 부호이며 비트 클럭 신호의 재생 능력과 높은 에러 제어 능력을 가지고 있다. 제안된 부호에서 데이터 0의 런 길이는 7 이하이고, 데이터 1의 밀도는 1/8 이상이며 최소 해밍 거리가 6임을 입증하였다. 제안된 부호를 사용하였을 때의 복호 에러 확률, 에러 검출 확률, 바른 복호 확률을 제시하였다. 기존의 다른 방식들에 비하여 오류 제어 능력이 우수함을 확인할 수 있었다.

• 한국국방경영분석학회지
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• 제16권2호
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• pp.118-134
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• 1990

This paper considers the mutual interference problem of several users employing the same FH systems in selected multiple user environments. The environment consists of a desired transmitter-receiver pair located in an area where there are M interfering users distributed in accordance with a specified probability density function. Both coherent Phase-Shift-Keyed and incoherent Frequencey-Shift-Keyed modulations are considered. The general formulas of the average bit error probability are derived. The calculation results are summarized and analyzed. The average bit error probability is highly dependent on the relative location of interferences to the desired link, the time duty factor of the hopping and the number of available channels.

• Current Optics and Photonics
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• 제3권4호
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• pp.311-319
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• 2019

A hybrid free-space-optical/radio-frequency (FSO/RF) communication system is considered, with the help of amplify-and-forward (AF) relaying. We consider various weather conditions to investigate their effects on the system's performance. We begin by obtaining the cumulative distribution function and probability density function of the end-to-end signal-to-noise ratio for the AF dual-hop FSO communication system with RF backup link. Then, these results are used to derive closed-form expressions for the outage probability, average bit-error rate, and average ergodic capacity. The results show that the considered system efficiently employs the complementary nature of FSO and RF links, resulting in impressive performance improvements compared to non-hybrid systems.

• Journal of information and communication convergence engineering
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• 제5권3호
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• pp.194-199
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• 2007

In this paper, a slotted CDMA_ALOHA protocol with hybrid ARQ is proposed for the wireless CDMA communication networks. The proposed protocol combines the characteristics of the slotted ALOHA, CDMA, and the hybrid ARQ, in order to increase the throughput by reducing the number of retransmissions when the channel experiences heavy traffic. The main feature of the proposed protocol is the utilization of the forward error correction capability to correct errors that appear after the CDMA dispreading of the packets. The base station does not need to ask so often for retransmission of erroneous packets. It will request for retransmission only when the FEC capability is exceeded. The performance of the proposed protocol is analyzed by considering the packet collision probability as well as the bit error probability. The numerical results show that the system throughput is closely related to the bit error rate of the wireless link and the FEC coding rate.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 G
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• pp.3239-3241
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• 1999

Two-dimensional optical code-division multiple access is a system to transmit a two- dimensional data via parallel transmission line. The probability density function (pdf) of interference noise from other users is calculated and the pdf of asynchronous interference noise is newly calculated to present lower bounds of probability of error. The corresponding bit error rate is evaluated from this results.