• Journal of KSNVE
• /
• v.8 no.6
• /
• pp.1181-1192
• /
• 1998

This paper describes the performance of a full-authority neural network-based fault tolerant system within a flight control system. This fault tolerant flight control system integrates sensor and actuator failure detection, identification, and accommodation (SFDIA and AFDIA), The first task is achieved by incorporating a main neural network (MNN) and a set of n decentralized neural networks (DNNs) to create a system for achieving fault tolerant capabilities for a system with n sensors assumed to be without physical redundancy The second scheme implements the same main neural network integrated with three neural network controllers (NNCs). The function of NNCs is to regain equilibrium and to compensate for the pitching, rolling. and yawing moments induced by the failure. Particular emphasis is placed in this study toward achieving an efficient integration between SFDIA and AFDIA without degradation of performance in terms of false alarm rates and incorrect failure identification. The results of the simulation with different actuator and sensor failures are presented and discussed.

• Journal of KIISE:Information Networking
• /
• v.34 no.4
• /
• pp.256-261
• /
• 2007

2-Dimensional Ring-banyan network is a high-performance fault-tolerant switching network using a deflection self-routing. The throughput of the switching network is better than that of Cyclic Banyan network under non-uniform traffic. In this paper, we present an analytic reliability analysis of the fault-tolerant switching network. We present the Mean-Time-to-Failure that is calculated by using probabilistic model. This model also takes into account a hardware complexity. In case of $16\;{\times}\;16$ size, the presented switching network is 1.275 times more reliable than Hui's switching network. And it is 1.510 times more reliable than Hui's network in case of $64\;{\times}\;64$ size.

• The KIPS Transactions:PartC
• /
• v.8C no.1
• /
• pp.23-31
• /
• 2001

Current CORBA has been suggested a solution for complexity of software in distributed environment. But it can't provide reliability about data transfer. For instance, CORBA can't provide object to client when the network are unstable or congested. In an existing CORBA, client has to wait when there is congestion between client and object implementation while client get a service from object implementation. So In this paper, we propose Fault-Tolerant CORBA Service (FTS) which has an intelligent redirection about an object that client requests. Moreover, we designed and implemented Fault-Tolerant Service to provide reliability by extending existing CORBA ORB. Therefore it provides reliable connection throughout the proposed Fault-Tolerant Service.

• The Journal of Information Technology
• /
• v.9 no.4
• /
• pp.25-34
• /
• 2006

As most application programs are more sophisticated and are adopted the distributed object technology, the object based distributed design became widespread since it supports portability and reusability. The approaches for fault-tolerant distributed computing are categorized into the active replica mechanism for mission-critical application programs and the passive replica mechanism for non mission-critical ones, when fault-tolerant facilities are added on. Our paper introduces the pros and drawbacks of several approaches for the add-on low-overhead fault-tolerant services by the surveys and shows the results of experiments for bench-mark models in order to demonstrate their performance.

• The Journal of the Korea Contents Association
• /
• v.8 no.8
• /
• pp.37-46
• /
• 2008

Launch control system controls the sequence for launching missile in weapon systems. This system have to generate the engagement plan, input information and launch the missile in timeliness requirement. Such a system may fail to operate correctly either due to errors in hardware and software or due to violation of timing constraints. We presented fault-tolerant ethernet for embedded real-time system like launch control system. This approach is designed to handle network faults using dual commercial-off-the-shelf(COTS) network devices. To support fault-tolerant ethernet each node is composed dual channel ethernet and designed the communication middleware for network fault detect and recovery. Especially for time-critical system, the middleware is being developed to achieve that no point of network failure shall take down or cause loss of communication to network nodes.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.18 no.10
• /
• pp.1553-1571
• /
• 1993

A significant amount of research has focused on the development of highly parallel architectures to obtain far more computational power than conventional computer systems. These architectures usually comprise of a large number of processors communicating through an interconnection network. The VLSI (Very Large Scale Integration) and WSI (Wafer Scale Integration) cellular arrays form one important class of those parallel architectures, and consist of a large number of simple processing cells, all on a single chip or wafer, each interconnected only to its neighbors. This paper studies three fundamental issues in these arrays : fault-tolerant reconfiguration. functional reconfiguration, and their integration. The paper examines conventional techniques, and gives an in-depth discussion about fault-tolerant reconfiguration and functional reconfiguration, presenting testing control strategy, configuration control strategy, steps required f4r each reconfiguration, and other relevant topics. The issue of integrating fault tolerant reconfiguration and functional reconfiguration has been addressed only recently. To tackle that problem, the paper identifies the relation between fault tolerant reconfiguration and functional reconfiguration, and discusses appropriate testing and configuration control strategy for integrated reconfiguration on VLSI and WSI cellular arrays.

• Journal of Institute of Control, Robotics and Systems
• /
• v.12 no.12
• /
• pp.1241-1248
• /
• 2006

In high reliability systems for industrial network such as railway signal system, fieldbus protocols have been known to satisfy the real-time and fault tolerant requirements. But, the application of fieldbus has been limited due to the high cost of hardware and software, and the difficulty in interfacing with multi-vendor products. Therefore, as an alternative to fieldbus, the computer network technology, especially Ethernet(IEEE 802.3), is being adapted to the industrial network. In this paper, we propose a switched Ethernet based railway signal system because of its very promising prospect for industrial application due to the elimination of uncertainties in the network operation. In addition, we propose the redundancy architecture for the reliability of network components. More specifically, this paper presents an analytical performance evaluation of switched Ethernet for railway signal system, and shows experimental evaluation of redundancy architecture.

• Proceedings of the Korean Information Science Society Conference
• /
• 2006.10d
• /
• pp.690-694
• /
• 2006

동적인 이동 네트워크는 다중의 무선 Ad-hoc 네트워크들로 구성된 독립적인 WPAN(Wireless Personal Network)이 모인 이동 네트워크의 한 종류이다. 휴대폰과 같은 모바일 장치들이 동적인 이동 네트워크에서 모바일 라우터로 동작하기 때문에 트래픽 과부하, 네트워크 신뢰도, 에너지 소모율 등의 네크워크 fail과 관련된 문제점 들이 제시된다. 따라서 동적인 이동 네트워크에서 fault tolerant 메커니즘은 필수적인 이슈가 될 것이다. 본 논문에서는 빠른 경로 변경 메커니즘과 추가적인 모바일 라우터 선정 메커니즘을 이용하여 향상된 fault tolerant 메커니즘을 제시한다. 최종적으로 모의실험을 통해 에너지 소모율과 패킷 손실 측면에서의 효율성을 보여줄 것이다.

• The Transactions of the Korea Information Processing Society
• /
• v.6 no.4
• /
• pp.1090-1097
• /
• 1999

the multi computers operated in harsh environments should be designed to guarantee normal operations in the presence of the component faults. One solution for this is a fault-tolerant routing. In the paper, we consider n-dimensional meshed network for the basic topology and propose a simple fault-tolerant routing algorithm that can transfer messages to their destination as desired in the presence of some component faults. the built algorithms basically adopts a WormHole(WH) routing method and uses the virtual channels sharing a physical channel for deadlock-freedom. Consequently, we show that the suggested algorithm has a higher performance than the X-Y routing algorithm through simulation results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2021.10a
• /
• pp.249-251
• /
• 2021

PBFT (Practical Byzantine Fault Tolerant) is a consensus algorithm that guarantees higher processing speed compared to PoW (Proof of Work) and absolute finality that records are not overturned due to the superiority of computing power. However, due to the complexity of the message, there is a limit that the network load increases exponentially as the number of participating nodes increases. PBFT is an important factor in determining the performance of a blockchain network, but studies on evaluation metrics and evaluation technologies are lacking. In this paper, we propose a PBFT evaluation framework that is convenient to change the consensus algorithm to easily evaluate quantitative indicators and improved methods for evaluating PBFT.