• 전자공학회논문지SC
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• 제48권4호
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• pp.71-79
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• 2011

본 논문에서는 이더넷 파워링크의 마스터 이중화 기법의 실시간성 향상을 위해 PReq 신호를 이용한 원전용 실시간 제어망의 실시간성과 신뢰성을 고려한 마스터 이중화 기법을 제안하였다. 제안된 마스터 이중화 기법은 동기 구간에서 PReq 신호를 이용하여 마스터 고장을 감지하고 비동기 구간에서 AMNI 프레임을 전송하여 단위 사이클 구간 앞서서 전환이 가능하다. 이를 통해 실시간 주기 데이터의 손실 및 이로 인한 문제점들을 최소한으로 줄일 수 있다. 제안된 마스터 이중화 기법의 효용성을 증명하기 위하여 OPNET Modeler를 이용하여 성능분석 및 검증을 수행하였고 이를 통해 마스터 전환시간을 줄일 수 있음을 보였다.

• 품질경영학회지
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• 제10권2호
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• pp.2-9
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• 1982

In principle the methods of increasing the reliability of complex system can be classified into the following four basic methods: (1) using the stand-by redundancy; (2) decreasing the failure rate of the system; (3) decreasing the time of continuous operation; (4) decreasing the mean repair time. Among the above four methods, it is generally known that the method of stand-by redundancy is the most effective general, to increase the reliability of systems. Therefor this paper aims to compare the gain in reliability which is achieved by applying stand-by redundancy with other methods, and to show the characteristics of each method From the comparison of the methods of increasing reliability, the following important facts are found: When the method of stand-by redundancy is used to increase the reliability of complex systems intended for long-term operation, a hight multiplicity of stand-by redundancy is required. Thus an increase of the reliability of complex system by applying stand-by redandancy is realized at the expense of characteristics such as weight, size, cost, increased complexity of operation conditions. And this property restricts its use in systems which are critical with respect to weight, size, cost or operation conditions. The method of stand-by redundancy is the most effective when this method is used to increase the reliability of complex systems intended for short-term operation, and the method of decreasing failure rate is the most effective when it is used to increase the reliability of systems intended for long-term use. The methods of increasing reliability discussed in this paper make it possible to make highly reliable systems. But it is not possible to make a highly reliable system using a single method of increasing reliability, even if it is the most effective one. Therefore it is recommended to use all or a majority of the above four methods by choosing it in accordance with the properties of the system under construction.

• 한국통신학회논문지
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• 제34권10B호
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• pp.1076-1085
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• 2009

본 논문에서는 3차원 동영상의 시간적 중복성과 룩업 테이블을 이용한 효과적인 3차원 동영상 홀로그램 생성방법을 제안한다. 기존의 N-LT를 이용한 홀로그램 생성 기법은 미리 생성된 요소 프린지 패턴을 단순 이동 시켜 물체에 대한 홀로그램을 고속으로 생성할 수 있게 하였다. 하지만, 3차원 동영상 홀로그램의 경우는 정지영상에 대한 홀로그램에 비해 방대한 양으로 인하여 실시간 홀로그램을 생성하는데 많은 시간이 필요하게 되어 실직적인 제한이 있었다. 반면 이러한 3차원 동영상은 인접한 프레임은 유사한 정보를 갖는다는 시간적 중복성을 갖고 있고, 이러한 특성을 동영상 압축에 이용하고 있다. 따라서 본 논문에서는 이러한 3차원 동영상의 시간적 중복성을 이용하여 계산하여야 하는 데이터의 양을 현저하게 줄임으로써 3차원 동영상에 대한 홀로그램을 고속으로 생성할 수 있는 새로운 방법을 제안하고 실험을 통하여 검증하였다.

• 한국항공우주학회지
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• 제39권12호
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• pp.1150-1159
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• 2011

신뢰도란 임의 시스템이 주어진 운용환경 하에서 의도한 기간 동안 의도된 기능을 정상적으로 수행할 확률로 정의된다. 신뢰도-중복 최적화 문제(RROP)는 비용, 무게 등의 제약내에서 시스템의 신뢰도를 최대화할 수 있는 최적의 부품을 선택하고, 부품수와 중복전략(활성/대기중복)을 결정하는 문제이다. 본 연구에서는 아리랑위성 2호의 다채널광학카메라(MSC) 시스템의 설계 구조를 바탕으로 RROP의 수리모형을 제시하고, NP-hard인 RROP의 해법으로써 병렬 개체군집최적화(PPSO) 알고리즘을 제안하였다. RROP 예제의 수치실험 결과는 계획된 수명기간에서 신뢰도를 최대화하는 시스템의 설계 구조를 제시한다.

• 대한산업공학회지
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• 제39권4호
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• pp.290-297
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• 2013

The increasing level of operation in high-tech industry is likely to require ever more complex structure in reliability problem. Furthermore, system failures are more significant on society as a whole than ever before. Reliability redundancy optimization problem (RROP) plays a important role in the designing and analyzing the complex system. RROP involves selection of components with multiple choices and redundancy levels for maximizing system reliability with constraints such as cost, weight, etc. Meanwhile, previous works on RROP dealt with system with perfect failure detection, which gave at most a good solution. However, we studied RROP with imperfect failure detection and switching. Using absorbing Markov Chain, we present not a good solution but the optimal one. In this study, the optimal system configuration is designed with warm and cold-standby redundancy for k-out-of-n system in terms of MTTF that is one of the performance measures of reliability.

• ETRI Journal
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• 제34권3호
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• pp.478-481
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• 2012

Testing memory and repairing faults have become increasingly important for improving yield. Redundancy analysis (RA) algorithms have been developed to repair memory faults. However, many RA algorithms have low analysis speeds and occupy memory space within automatic test equipment. A fast RA algorithm using simple calculations is proposed in this letter to minimize both the test and repair time. This analysis uses the grouped addresses in the faulty bitmap. Since the fault groups are independent of each other, the time needed to find solutions can be greatly reduced using these fault groups. Also, the proposed algorithm does not need to store searching trees, thereby minimizing the required memory space. Our experiments show that the proposed RA algorithm is very efficient in terms of speed and memory requirements.

• International Journal of Aeronautical and Space Sciences
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• 제7권1호
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• pp.73-83
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• 2006

In this paper, a redundancy management system for aircraft is studied, and fault detection and isolation algorithms of inertial sensor system are proposed. Contrary to the conventional aircraft systems, UAV system cannot allow triple or quadruple hardware redundancy due to the limitations on space and weight. In the UAV system with dual sensors, it is very difficult to identify the faulty sensor. Also, conventional fault detection and isolation (FDI) method cannot isolate multiple faults in a triple redundancy system. In this paper, two FDI techniques are proposed. First, hardware based FDI technique is proposed, which combines a parity equation approach with a wavelet based technique. Second, analytic FDI technique based on the Kalman filter is proposed, which is a model-based FDI method utilizing the threshold value and the confirmation time. To provide the reference value for detecting the fault, residuals are calculated using the extended Kalman filter. To verify the effectiveness of the proposed FDI methods, numerical simulations are performed.

• ETRI Journal
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• 제41권1호
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• pp.52-60
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• 2019

A fast hologram calculation approach is proposed to reduce computational load by avoiding the recalculation of redundancy information. In the proposed method, the hologram is divided into several sub-holograms that record and reconstruct different views of 3D objects. The sub-hologram is generated from its adjacent calculated sub-holograms by only adding the holograms of difference images between an adjacent pair of views. The repetitive information of two adjacent views is called angular redundancy. Therefore, avoiding the recalculation of this angular redundancy can considerably reduce the computational load. Experimental results confirm that the proposed method can reduce the computational time for the statue head, rabbits, and car to 4.73%, 6.67%, and 10.4%, respectively, for uniform intensity, and to 56.34%, 57.9%, and 66.24%, respectively, for 256 levels intensity, when compared to conventional methods.

• Journal of Communications and Networks
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• 제18권1호
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• pp.123-131
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• 2016

The high-availability seamless redundancy (HSR) protocol is one of the most important redundancy IEC standards that has garnered a great deal of attention because it offers a redundancy with zero recovery time, which is a feature that is required by most of the modern substation, smart grid, and industrial field applications. However, the HSR protocol consumes a lot of network bandwidth compared to the Ethernet standard. This is due to the duplication process for every sent frame in the HSR networks. In this paper, a novel algorithm known as the reducing multicast traffic (RMT) is presented to reduce the unnecessary redundant multicast traffic in HSR networks by limiting the spreading of the multicast traffic to only the rings that have members associated with that traffic instead of spreading the traffic into all the network parts, as occurs in the standard HSR protocol. The mathematical and the simulation analyses show that the RMT algorithm offers a traffic reduction percentage with a range of about 60-87% compared to the standard HSR protocol. Consequently, the RMT algorithm will increase the network performance by freeing more bandwidth so as to reduce HSR network congestion and also to minimize any intervention from the network administrator that would be required when using traditional traffic filtering techniques.

• 한국시뮬레이션학회논문지
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• 제18권4호
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• pp.59-66
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• 2009

VLSI(Very Large Scale Integration)와 WSI(Wafer Scale Integration)와 같은 통합기술로 인해 큰 용량의 메모리 대량생산이 가능 하게 된 지금 Redundancy는 메모리 칩의 제조와 결함이 있는 셀을 지닌 디바이스를 치료하는데 광범위하게 사용되어져왔다. 메모리칩의 밀도가 증가함에 따라 결함의 빈도 또한 증가한다. 많은 결함이 있다면 어쩔 수 없겠지만 적은 결함이 발생한 경우에는 해당 다이를 reject 시키는 것 보다는 수선해서 사용하는 것이 메모리생산 업체 입장에서는 보다 효율적이고 원가 절감 차원에서 필수적이다. 이와 같은 이유로 laser repair라는 공정이 필요하고 laser repair공정의 정확한 타깃을 설정하기 위해 redundancy analysis가 필요하게 되었다. CRA시뮬레이션은 기존의 redundancy analysis 알고리즘의 개념에서 벗어나 결함 유형별로 시뮬레이션한 후 RA를 진행함으로써 RA에 소요되는 시간을 절약함으로써 원가 경쟁력 강화를 할 수 있다.