• 한국정보통신학회논문지
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• 제24권11호
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• pp.1558-1561
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• 2020

In this paper, we propose a blockchain scheme to enhance fault tolerance in distributed storage blockchain systems. Traditional blockchain systems suffer from ever-increasing storage cost. To overcome this problem, distributed storage blockchain techniques have been proposed. Distributed storage blockchain schemes effectively reduce the storage cost, but there are still limitations in reducing recovery cost and fault tolerance. The proposed approach recovers multiple errors within a group by utilizing locally repairable codes with availability. This improves the fault tolerance of the blockchain systems. Simulation results show that the proposed scheme enhances the fault tolerance while minimizing storage cost and recovery cost compared to other state-of-art schemes.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 I
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• pp.398-401
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• 2003

In this paper, the basic concept and approach method of ideal communication among fault tolerance system has been studied and suggested. Fault tolerance should not be treated like Fault Avoidance and Fault Prevention. In this paper, Key specifications of mechanical and electrical characteristics of communication methods for fulfilling the requirements to meet the general purpose of fault tolerance system has been analyzed and presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.875-877
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• 2003

This paper use fault location algorithm for single-phase-to-ground faults on the teed circuit of a parallel transmission line that use only local end voltage and current information. When Newton-Raphson iteration method is used, the Initial value may cause error or cause not suitable result. Suggested new calculation model uses NVP methodology, which is one of the fault tolerance technology to solve this problem. EMTP simulation result has shown effectiveness of the algorithm under various conditions.

• ETRI Journal
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• 제24권1호
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• pp.12-22
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• 2002

A Mobile IP allows IP hosts to move between different networks without changing their IP addresses. Mobile IP systems supporting local registration were introduced to reduce the number of times a home registration with the remotely located home agent was needed. The local registration Mobile IP scheme enhanced performance by processing registration requests of mobile nodes at a local agent. The local registration approach may affect other aspects of the Mobile IP systems such as fault tolerance. In this paper, we briefly review previous solutions for supporting fault tolerance in local registration Mobile IP systems and propose a fault tolerance protocol with a backup foreign agent in a hierarchical local registration mobile IP to enhance the efficiency of such systems against foreign agent failures. We also describe the specification of the proposed protocol using LOTOS and perform its validation using MiniLite. Finally, we analyze the performance of our proposed fault tolerance protocol through simulation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권11호
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• pp.5290-5304
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• 2016

With the growth of the massive amount of data, the failure probability of the cloud storage node is becoming more and more big. A single fault tolerance strategy, such as replication and erasure codes, has some unavoidable disadvantages, which can not meet the needs of the today's fault tolerance. Therefore, according to the file access frequency and size, an adaptive hybrid redundant fault tolerance strategy is proposed, which can dynamically change between the replication scheme and erasure codes scheme throughout the lifecycle. The experimental results show that the proposed scheme can not only save the storage space(reduced by 32% compared with replication), but also ensure the fast recovery of the node failures(increased by 42% compared with erasure codes).

• 대한전자공학회논문지
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• 제24권4호
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• pp.610-617
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• 1987

This thesis is concerned with fault-tolerance of a B-net (Beta-network) which is a kind of interconnection network in the multicomputer system. In this paper, a method for obtaining Maximal Tolerable Fault Set(MTFS) of link line connecting switching elements in the arbitrary B-net is presented. Using this method, it is seen that testing of DFA capability is possible when s-a-faults of link line occur, and criterion for determining degree of fault- tolerance of a B-net in terms of link line is introduced.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권1호
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• pp.35-57
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• 2021

Fog computing aims to provide the solution of bandwidth, network latency and energy consumption problems of cloud computing. Likewise, management of data generated by healthcare IoT devices is one of the significant applications of fog computing. Huge amount of data is being generated by healthcare IoT devices and such types of data is required to be managed efficiently, with low latency, without failure, and with minimum energy consumption and low cost. Failures of task or node can cause more latency, maximum energy consumption and high cost. Thus, a failure free, cost efficient, and energy aware management and scheduling scheme for data generated by healthcare IoT devices not only improves the performance of the system but also saves the precious lives of patients because of due to minimum latency and provision of fault tolerance. Therefore, to address all such challenges with regard to data management and fault tolerance, we have presented a Fault Tolerant Data management (FTDM) scheme for healthcare IoT in fog computing. In FTDM, the data generated by healthcare IoT devices is efficiently organized and managed through well-defined components and steps. A two way fault-tolerant mechanism i.e., task-based fault-tolerance and node-based fault-tolerance, is provided in FTDM through which failure of tasks and nodes are managed. The paper considers energy consumption, execution cost, network usage, latency, and execution time as performance evaluation parameters. The simulation results show significantly improvements which are performed using iFogSim. Further, the simulation results show that the proposed FTDM strategy reduces energy consumption 3.97%, execution cost 5.09%, network usage 25.88%, latency 44.15% and execution time 48.89% as compared with existing Greedy Knapsack Scheduling (GKS) strategy. Moreover, it is worthwhile to mention that sometimes the patients are required to be treated remotely due to non-availability of facilities or due to some infectious diseases such as COVID-19. Thus, in such circumstances, the proposed strategy is significantly efficient.

• 한국정보처리학회논문지
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• 제4권8호
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• pp.1930-1939
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• 1997

본 논문에서는 최근에 [12]에 제시된 그레이 큐브의 고장 지름(fault diameter)과 고장 허용도(fault tolerance)를 분석한다. 상호 연결망의 고장 지름은 연결망을 평가하기 위한 중요한 척도중 하나로서 노드들이 고장인 경우 노드를 사이에 최장 거리를 나타낸다. $2^n$개의 노드를 가지는 n-차원 그레이큐브의 고장 지름이 지름 +2임을 보인다.($n{\ge}3$). 이는 노드들이 고장인 환경에서도 노드들 사이의 최장 거리가 단지 상수 요소밖에 증가하지 않음을 나타낸다. 이 결과를 널리 알려진 하이퍼큐브의 고장 지름과 비교하면 노드 고장인 환경에서도 메시지의 최장 전달 거리가 하이퍼큐브의 그것에 비해 약 절반 정도임을 보이고 있다.

• 한국정보과학회논문지:시스템및이론
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• 제31권3_4호
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• pp.204-212
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• 2004

분산 시스템에서는 단일 시스템보다 높은 결함 발생 확률을 가지기에 기존의 맡은 연구에서는 분산 시스템에서 결함 발생에 대한 맡은 결함 포용 기법들이 연구되어 왔다. 하지만 저장된 결함 포용 정보의 증가에 따른 저장 공간의 부족으로 인해 전체 시스템 성능의 저하를 가져오게 하였다. 시스템 성능의 저하를 막기 위하여 불필요한 결함 포용 정보의 삭제가 필요하게 되었고 이 논문에서는 결함 포용 정보의 쓰레기 처리를 위한 방법을 제안한다. 이에 본 논문에서는 결함 포용 정보의 쓰레기 처리를 담당하는 쓰레기 처리 에이전트, 결함 포용 정보를 유지 관리하는 정보 에이전트, 그리고 전체 에이전트간의 통신 기능을 담당하는 조정 에이전트를 정의 및 설계하고, 쓰레기 처리 에이전트를 이용한 쓰레기 처리 알고리즘을 제안한다. 복귀회복 기법은 독립 검사점(independent checkpoint)기법과 송신자 기반 비관적 매시지 로깅(sender based pessimistic message logging)기법을 사용한다. 제안된 쓰레기 처리 기법에서의 쓰레기 처리, 정보, 조정 에이전트는 프로세스와 동시에 생성되며 정보 에이전트에 프로세스에서 발생하는 검사점과 비결정적인 사건들에 대한 로깅 정보들을 영역 지식으로 구축한다. 그리고 쓰레기 처리 에이전트는 쓰레기 처리 시점을 선정하고 정보 에이전트와 조정에이전트의 협력을 통하여 영역 지식에 구축된 불필요한 결함 포용 정보의 쓰레기 처리를 한다. 제안한 에이전트를 이용한 쓰레기 처리기법의 타당성 증명을 위하여 결함을 발생시켜 복귀 회복 후 쓰레기 처리를 하는 시스템과 하지 않는 시스템의 영역지식을 비교하여 같은 결과를 같는지의 여부를 검사한다

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권3호
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• pp.735-748
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• 2014

The fault-tolerance routing problem is one of the most important issues in the application of the Internet of Things, and has been attracting growing research interests. In order to maintain the communication paths from source sensors to the macronodes, we present a hybrid routing scheme and model, in which alternate paths are created once the previous routing is broken. Then, we propose an improved efficient and intelligent fault-tolerance algorithm (IEIFTA) to provide the fast routing recovery and reconstruct the network topology for path failure in the Internet of Things. In the IEIFTA, mutation direction of the particle is determined by multi-swarm evolution equation, and its diversity is improved by the immune mechanism, which can improve the ability of global search and improve the converging rate of the algorithm. The simulation results indicate that the IEIFTA-based fault-tolerance algorithm outperforms the EARQ algorithm and the SPSOA algorithm due to its ability of fast routing recovery mechanism and prolonging the lifetime of the Internet of Things.