• Nuclear Engineering and Technology
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• 제53권7호
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• pp.2357-2363
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• 2021

Silicon carbide is widely used in radiation environments due to its excellent properties. However, when exposed to the strong radiation environment constantly, plenty of defects are generated, thus causing the material performance downgrades or failures. In this paper, the two-temperature model (2T-MD) is used to explore the defect recovery process by applying the electronic energy loss (Se) on the pre-damaged system. The effects of defect concentration and the applied electronic energy loss on the defect recovery process are investigated, respectively. The results demonstrate that almost no defect recovery takes place until the defect density in the damage region or the local defect density is large enough, and the probability of defect recovery increases with the defect concentration. Additionally, the results indicate that the defect recovery induced by swift heavy ions is mainly connected with the homogeneous recombination of the carbon defects, while the probability of heterogeneous recombination is mainly dependent on the silicon defects.

• ETRI Journal
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• 제44권2호
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• pp.274-285
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• 2022

Retransmission in optical burst switching networks is a solution to recover data loss by retransmitting the dropped burst. The ingress node temporarily stores a copy of the complete burst and sends it each time it receives a retransmission request from the core node. Some retransmission schemes have been suggested, but uncontrolled retransmission often increases the network load, consumes more bandwidth, and consequently, increases the probability of contention. Controlled retransmission is therefore essential. This paper proposes a new controlled retransmission scheme for loss recovery, where the available bandwidth of wavelength channels and the burst lifetime are referred to as network conditions to determine whether to transmit a dropped burst. A retrial queue-based analysis model is also constructed to validate the proposed retransmission scheme. The simulation and analysis results show that the controlled retransmission scheme is more efficient than the previously suggested schemes regarding byte loss probability, successful retransmission rate, and network throughput.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권9호
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• pp.4548-4559
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• 2018

Conditional differential attack against NFSR-based cryptosystems proposed by Knellwolf et al. in Asiacrypt 2010 has been widely used for analyzing round-reduced Grain v1. In this paper, we present improved conditional differential attacks on Grain v1 based on a factorization simplification method, which makes it possible to obtain the expressions of internal states in more rounds and analyze the expressions more precisely. Following a condition-imposing strategy that saves more IV bits, Sarkar's distinguishing attack on Grain v1 of 106 rounds is improved to a key recovery attack. Moreover, we show new distinguishing attack and key recovery attack on Grain v1 of 107 rounds with lower complexity O($2^{34}$) and appreciable theoretical success probability 93.7%. Most importantly, our attacks can practically recover key expressions with higher success probability than theoretical results.

• 한국통신학회논문지
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• 제28권4B호
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• pp.288-297
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• 2003

TCP Reno 는 하나의 윈도우 내에서 다수 개의 패킷 손실이 발생하는 경우 손실된 패킷들을 효율적으로 복구하는 것이 불가능한 문제점을 가지과 있다. 이 문제점을 개선하기 위해서 설계된 TCP New-Reno 는 부분 스인 패킷(partial acknowledgement)를 통해 fast recovery를 연장함으로써 다수 개의 패킷 손실이 발생하더라도 이들을 재전송에 의해 복구하는 것이 가능하다. 그러나 TCP New-Reno 역시 재전송 패킷들이 다시 손질되는 경우 불가피한 RTO(Retransmission Timeout)가 발생한다는 문제점을 가지고 있다. 이런 문제점을 개선하기 위해서 중복 승인 패킷 수를 근거로 재전송 패킷 손실을 감지할 수 있는 DAC(Duplicate Acknowledgement Counting) 알고리듬을 제안한다. TCP Reno. TCP New-Reno 그리고 DAC를 사용하는 경우에 대해 손실 복구 과정을 정확하게 모델링하고 손실된 패킷이 복구되기 위한 조건들을 유도한다. 임의 패킷 손실 확률에 대한 손실 복구 확률을 수학적으로 계산하고 이를 통해 DAC가 TCP New-Reno 의 손실 복구 기능을 향상시킬 수 있다는 것을 보인다.

• 대한산업공학회지
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• 제42권1호
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• pp.38-49
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• 2016

This paper proposes a mathematical model-based solution for sourcing decisions with an objective of minimizing the manufacturer's total cost in the two-echelon supply chain with supply capacity risk. The risk impact is represented by uniform, beta, and triangular distributions. For the mathematical model, the probability vector of normal, risk, and recovery statuses are developed by using the status transition probability matrix and the equations for estimating the supply capacity under risk and recovery statuses are derived for each of the three probability distributions. Those formulas derived are validated using the sampling method. The results of the simulation study on the test problem show that the sourcing decisions using the proposed solution reduce the total cost by 1.6~3.7%, compared with the ones without a consideration of supply capacity risk. The total cost reduction increases approximately in a linear fashion as the probability of risk occurrence or reduction rate of supply capacity due to risk events is increased.

• 정보보호학회논문지
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• 제29권1호
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• pp.139-147
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• 2019

본 연구에서는 손상된 전자기록물을 구분할 수 있는 방법과 손상 형태별 전자 기록물 복원 방법을 제안한다. 제안되는 구분 엔진과 복원 엔진은 전자기록물의 형태 및 구조를 기반으로 손상 전자 기록물을 분류하고, 손상된 형태에 따라 복원 확률을 높인다. 이러한 과정을 통해 멸실되는 전자기록물을 최소화하는 방법을 제안하고, 이를 실험을 통해 검증한다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2010년도 하계학술대회
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• pp.61-63
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• 2010

Recent work in compressed sensing theory shows that m${\times}$n independent and identically distributed sensing matrices whose entries are drawn independently from certain probability distributions guarantee exact recovery of a sparse signal with high probability even if m${\ll}$n. In particular, it is well understood that the L1 minimization algorithm is able to recover sparse signals from incomplete measurements. In this paper, we propose a novel sparse signal reconstruction method that is based on the reweighted L1 minimization via support recovery.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 추계종합학술대회
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• pp.927-930
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• 2005

ACSR은 실시간 시스템을 기술하고 분석하기 위한 시간 프로세스 대수학으로서, 동기적으로 발생 하는 timed action과 비동기적으로 발생하는 event의 기술을 지원한다. ACSR의 선택 연산에 확률개념을 도입하여 확장한 대수학이 PACSR이다. 이 논문은 PACSR을 이용하여 일반적인 자원할당시스템에서 시스템 오류의 발생 및 그 오류로부터의 복구 과정을 기술하고자 한다. 시스템 오류 발생과정이 오류 발생 확률과 복구 확률로부터 분석 가능함을 보였다.

• 한국주거학회논문집
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• 제16권5호
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• pp.67-74
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• 2005

The performance of building should be deteriorated with time while the building would maintain and manage the function and performance to get a living condition. For the efficient maintenance of the building, the repair cycle would be provided and applied during the service-life time. The service-life time of the building components would be needed to determine the repair time and the repair scope. The service-life time of the building components would be calculated with the 1st repair time and the recovery rate of the performance, considering the recovery rate after repaired. In this paper, the 1st repair time would be estimated with the normal probability distribution, choice probability and 3rd quadratic function. The recovery rate of the building components assumes various level according to the research target and utility area. The results of this study are as follows ; first, most of the components of the building work would range about 30 years in the service-life time and the components of the mechanical works range from 28 years to 37 years, those of the electrical works would be about 31 years.

• 한국통신학회논문지
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• 제29권7B호
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• pp.650-659
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• 2004

국내 무선 네트워크 환경은 사용자의 서비스 요구 수용과 시장 성장으로 인해 빠르게 변화하고 있다. 이에 따라 무선 구간에서 TCP(transmission control protocol)를 이용한 신뢰성 있는 데이터 전송도 늘어날 전망이다. TCP는 유선 네트워크에서 사용함을 가정으로 만들어졌기 때문에 무선에서 발생할 수 있는 비 혼잡 손실에 의해 많은 성능 저하를 겪을 수 있다. 특히 RTO(retransmission timeout)은 TCP의 성능에 많은 영향을 미친다. 본 논문에서는 송신단에서 fast recovery과정 중에 발생한 패킷 손실을 빠르게 감지하여 RTO없이 복구함으로써 성능저하를 줄일 수 있는 DAC$^{＋}$(Duplicate Acknowledgement Counting)와 EFR(Extended Fast Recovery)을 제안한다. 제안 알고리듬을 TCP NewReno와 비교했을 때 정상 상태에서 fast recovery 확률이 높고, 이에 따른 RTO 감소로 인해 response time이 줄어드는 것을 확인할 수 있다.