• 한국통신학회:학술대회논문집
• /
• 한국통신학회 2006년도 하계종합학술발표회 논문 초록집
• /
• pp.732-732
• /
• 2006

• 대한전기학회논문지:시스템및제어부문D
• /
• 제55권12호
• /
• pp.534-543
• /
• 2006

BACnet(Building Automation and Control networks) is a standard data communication network protocol designed specifically for building automation and control systems. BACnet provides BACnet/IP Protocol for data communication through the Internet. BACnet device uses BBMD(BACnet Broadcasting Management Device) to deliver BACnet broadcast messages. In this study, we propose a fault tolerant BBMD in the BACnet/IP protocol. The fault tolerant BBMD improves the connectivity of BACnet/IP networks by inheriting the operation of original BBMD in the networks. The fault tolerant BBMD is implemented with added functions to the original BACnet/IP protocol so that it can provide backward compatibility with the original BACnet/IP devices. We examined the validity of the fault tolerant BBMD using an experimental model.

• International Journal of Control, Automation, and Systems
• /
• 제6권3호
• /
• pp.351-363
• /
• 2008

This paper is concerned with tasking and guidance of networked airborne sensors to achieve fault-tolerant sensing. The sensors are coordinated to locate hostile transmitters by intercepting and processing their signals. Faults occur when some sensor-carrying vehicles engaged in target location missions are lost. Faults effectively change the network architecture and therefore degrade the network performance. The first objective of the paper is to optimally allocate a finite number of sensors to targets to maximize the network life and availability. To that end allocation policies are solved from relevant Markov decision problems. The sensors allocated to a target must continue to adjust their trajectories until the estimate of the target location reaches a prescribed accuracy. The second objective of the paper is to establish a criterion for vehicle guidance for which fault-tolerant sensing is achieved by incorporating the knowledge of vehicle loss probability, and by allowing network reconfiguration in the event of loss of vehicles. Superior sensing performance in terms of location accuracy is demonstrated under the established criterion.

• 한국정보과학회논문지:정보통신
• /
• 제31권3호
• /
• pp.335-346
• /
• 2004

본 논문에서는 편향 자기 경로 제어 방법을 사용하는 새로운 고성능 고장 감내 스위칭 망을 제시하고, 이 스위칭 망의 고장 진단 방법을 제안한다. 우리는 기본 스위치인 벤얀 망의 각 스위칭 단계들이 하나의 순환 군의 나열로 구성되어 있다는 사실과 자기 경로제어 관점에서 인접한 스위칭 단계들 간에 준동형(Homomorphism)이 존재하기 때문에, 모든 각 단계의 순환 군이 이 다음 단계의 부분군이고, 이들 단계들로 구성된 펙터 군이 존재한다는 성질과 사용하여, 결함이 생긴 링크들을 우회하는 대체 경로들로 추가한 링크들을 포함하는 모든 링크들을 사용하는 확장 벤얀 망인 다단 스위칭 망을 제시한다. 그리고 이 망의 성능을 시뮬레이션을 통해서 분석하여, 성능의 우수함을 보인다. 또한 이들 다중 경로를 제공하는 스위칭 망을 사용하는데 필수적인 결함 진단법을 제시한다.

• 한국통신학회논문지
• /
• 제21권2호
• /
• pp.447-460
• /
• 1996

Network optimization and design procedures often separate quality of service (QOS) performance measures from reliability issues. This paper considers channel allocation and flow assignment (routing) in a network subject to link failures. Fault-tolerant channel allocation and flow assingments are determined which minimize network cost while maintaining QOS performance requirements. this approach is shown to yield significant network cost reductions compared to previous heuristic methods used in the design of packet switched network with unreliable links.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2005년도 ICCAS
• /
• pp.756-760
• /
• 2005

By development of a robot technology, personal robot is being developed very actively. Various infra-technologies are accumulated in hardware and software how by internal a lot of research and development efforts, and it is circumstance that actual commodity is announced. But, personal robot is applied to be acting near human, and takes charge of safety and connected directly a lot of works of home security, gas-leakage, fire-warning facilities, or/and etc. So personal robot must do safe and stable action even if any unexpected accidents are happened, important functions are always operated. In this paper, we are wished to show design structures for supporting fault-tolerant operation from our real-time robot middleware viewpoint. Personal robot, in being developed, was designed by module structure to do to interconnect and to interoperate among each module that is mutually implemented by each research facilities or company. Also, each modules can use appreciate network system that is fit for handling and communicating its data. To guarantee this, we have being developed a real-time network middleware, for especially personal robot. Recent our working is to add and to adjust some functions like connection management, distributed routing mechanism, remote object management, and making platform independent robot application execution environment with self-moving of robot application, for fault-tolerant personal robot.

• 품질경영학회지
• /
• 제21권1호
• /
• pp.78-95
• /
• 1993

The art of designing and analyzing fault-tolerant computers is surveyed with special emphasis on problems of analyzing the behavior of computers that have autonomous repair capability. The survey covers the following topics : (1) general issues in computer reliability, (2) fault-tolerance state relations and requirements, (3) computational hierarchy, (4) fault characteristics, (5) fault diagnosis, (6) fault-tolerance schemes for logic network and machines, (7) fault-coverage effects, and (8) fault-tree analysis of coverage. This paper does not include techniques for verifying nonredundant hardware or system software designs or for verifying the correctness of application programs.

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2005년도 추계학술발표대회 및 정기총회
• /
• pp.1359-1362
• /
• 2005

본 논문은 차량 및 공장 자동화 분야에서 널리 쓰이고 있는 Controller Area Network 의 안정성 보장을 위한 Fault-Tolerant 프로토콜을 제안한다. 제안된 Fault-Tolerant 프로토콜은 실시간 Fault-Tolerant 시스템을 대상으로 한 Time-Triggered 프로토콜의 중복 메커니즘을 이용하며 event-triggered 방식인 CAN 에 알맞게 변형하여 이용한다. 본 논문의 프로토콜은 Atmel 사의 AT89C51CC03 을 이용하여 구현하여 가능성을 검증 하였다. 제시한 프로토콜을 이용하여 엔진과 X-by-Wire, ABS 분야와 같은 안정성-중시 시스템에 좀더 높은 안정성을 부여할 수 있을 것이다.

• Nuclear Engineering and Technology
• /
• 제54권9호
• /
• pp.3283-3292
• /
• 2022

Based on the Deep Q-Network(DQN) algorithm of reinforcement learning, an active fault-tolerance method with incremental action is proposed for the control system with sensor faults of the once-through steam generator(OTSG). In this paper, we first establish the OTSG model as the interaction environment for the agent of reinforcement learning. The reinforcement learning agent chooses an action according to the system state obtained by the pressure sensor, the incremental action can gradually approach the optimal strategy for the current fault, and then the agent updates the network by different rewards obtained in the interaction process. In this way, we can transform the active fault tolerant control process of the OTSG to the reinforcement learning agent's decision-making process. The comparison experiments compared with the traditional reinforcement learning algorithm(RL) with fixed strategies show that the active fault-tolerant controller designed in this paper can accurately and rapidly control under sensor faults so that the pressure of the OTSG can be stabilized near the set-point value, and the OTSG can run normally and stably.

• Journal of Electrical Engineering and Technology
• /
• 제13권4호
• /
• pp.1740-1751
• /
• 2018

This paper proposes a novel fault tolerant tracking control (FTTC) scheme for a class of nonlinear systems with actuator failures based on the policy iteration (PI) algorithm and the adaptive fault observer. The estimated actuator failure from an adaptive fault observer is utilized to construct an improved performance index function that reflects the failure, regulation and control simultaneously. With the help of the proper performance index function, the FTTC problem can be transformed into an optimal control problem. The fault tolerant tracking controller is composed of the desired controller and the approximated optimal feedback one. The desired controller is developed to maintain the desired tracking performance at the steady-state, and the approximated optimal feedback controller is designed to stabilize the tracking error dynamics in an optimal manner. By establishing a critic neural network, the PI algorithm is utilized to solve the Hamilton-Jacobi-Bellman equation, and then the approximated optimal feedback controller can be derived. Based on Lyapunov technique, the uniform ultimate boundedness of the closed-loop system is proven. The proposed FTTC scheme is applied to reconfigurable manipulators with two degree of freedoms in order to test the effectiveness via numerical simulation.