• Journal of the Korean Society for Railway
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• v.10 no.5
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• pp.527-532
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• 2007

In this paper, we suggest those two design plans for power supply method of Hot Standby Sparing System; one is the plan using MTBF based on Constant Failure Rate, and the plan using Reliability Function is the other. Traditionally, RBD (Reliability Block Diagram) is used for reliability prediction which is required to meet any requirements before system operation. However, the system that has redundancy, such as Hot Standby Sparing System, Is not suitable for system reliability modeling using combination model, such as RBD. In this paper, therefore, we demonstrate that for redundancy controller, redundancy modeling design toward fault occurrence design is more effective to build up a system with higher reliability and achieve the effectiveness of loss cost due to maintenance and failure occurred in operation, rather than combinational modeling design.

• Journal of the Korean Data and Information Science Society
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• v.14 no.4
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• pp.1055-1065
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• 2003

We shall propose maximum likelihood, Bayesian and generalized maximum likelihood estimation for the reliability of the two-unit hot standby system with exponential lifetime distribution that switch is perfect. Each estimation will be compared numerically in terms of various mission times, parameter values and asymptotic relative efficiency through Monte Carlo simulation.

• Journal of the Korean Data and Information Science Society
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• v.15 no.1
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• pp.239-250
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• 2004

We shall propose maximum likelihood, Bayesian and generalized maximum likelihood estimation for the reliability of the two-unit hot standby system with Rayleigh lifetime distribution that switch is perfect. Each estimation will be compared numerically in terms of various mission times, parameter values and asymptotic relative efficiency through Monte Carlo simulation.

• Journal of the Korean Data and Information Science Society
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• v.9 no.1
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• pp.89-94
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• 1998

We shall propose several Bayes estimators for reliability of a two-unit hot standby system with the imperfect switch based upon a complete sample of failure times observed from an exponential distribution, and the proposed reliability Bayesian estimators are compared numerically each other in sense of mean squared error.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.352-359
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• 2000

In this paper, the method is used that each system isolates the part in which faults are occurred in case of fault occurrence since total system is designed in the type of hot standby sparing system construction and self-checking circuit in each system is attached to the memory being of the high failure rate in common communication system. Thus reliability and availability in system are improved. In this thesis, self-checking circuit was designed using 2 out of 6 code and didn't have any effect to the system operation. For the purpose of verification, each system attached with self-checking circuit was simulated through fault injection arid the continuity of each system in hot standby sparing system was tested in case that the system was switched when faults in the system were occurred.

• Journal of Ocean Engineering and Technology
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• v.29 no.5
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• pp.380-385
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• 2015

In the development of an underwater construction robot, the reliability of the operating system is the most important issue because of its huge maintenance cost, especially in a deep sea application. In this paper, we propose a new redundant architectural design for the hydraulic control system of an underwater construction robot. The proposed architecture consists of dual independent modular redundancy management systems linked with a commercial profibus network. A cold standby redundancy management system consisting of a preprocessing switch circuit is applied to the signal network, and a hot standby redundancy management system is adapted to utilize two main controllers.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.10A
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• pp.1113-1122
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• 2004

This paper is basically to achieve the high-availability and high-reliability of the control system from the implementation of the fault-tolerant system using the hot-standby sparing technique. To meet the objective, we design and implement a board with fault tolerance I/O bus to detect the fault. Warm-standby sparing technique is the fault tolerance technique usually used for switching control system in present. This technique can be easily implemented, but can not detect the fault quickly and can malfunction because of the hardware fault. The hot-standby sparing fault tolerant technique implemented in this paper is consists of dual processor modules and a I/O processor using fault tolerant I/O bus. The proposed method can find the faults as soon as possible, so it can prevent from wrong operation. Also it is possible to normal re-service due to the short recovering time. To implement the fault-tolerant dual system with fault detection be, two daughter, called FTMA and FTIA, boards designed and implemented are applied to the system. And we also simulated the proposed method to verify the high-availability and high-reliability of the control system using Markov process.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.4
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• pp.179-186
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• 2015

In this study, the actual energy consumption of the secondary side District Heating System (DHS) with different hot water supply temperature control methods is compared. The two methods are Outdoor Temperature Reset Control and Outdoor Temperature Predictive Control. While Outdoor Temperature Reset Control has been widely used for energy savings of the secondary side system, the results show that the Outdoor Temperature Predictive Control method saves more energy. In general, the Outdoor Temperature Predictive Control method lowers the supply temperature of hot water, and it reduces standby losses and increases the overall heat transfer value of heated spaces due to more flow into the space. During actual energy consumption monitoring, the Outdoor Temperature predictive Control method saves about 6.6% of energy when compared to the Outdoor Temperature Reset Control method. Also, it is found that at partial load condition, such as during daytime, the fluctuation of hot water supply temperature with Outdoor Temperature Reset Control is more severe than that with Outdoor Temperature Predictive Control. Thus, it proves that Outdoor Temperature Predictive Control is more stable even at partial load conditions.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.168-171
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• 1999

A fault-tolerant system should have a high availability and high reliability to maintain a given system stable against sudden faults in the system. In this paper, we propose a new types of fault tolerant system based on a fault detection bus. The fault detection bus is designed and implemented to detect any errors by comparing event-output signals from two processor modules. It employs the hot standby sparing fault detection method〔1〕 to provide continuity of services even if a system fault occurs. The prototype fault tolerant system is currently being implemented on a management system with two processor modules.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.4
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• pp.168-176
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• 2001

In this paper, we develop a dual-duplex system which detects a fault by hardware comparator and switches to hot standby redundancy. This system is designed on the basis of MC68000 and can be used in VMEbus. To improve reliability, the dual-duplex system is designed in dual modular redundancy. The failure rate of electrical element is calculated in MILSPEC-217F, and the system RAMS(Reliability, Availiability, Maintainability and Safety) and MTTF(Mean Time to Failure) are evaluated by Markov modeling method. As the evaluation result shows improved reliability, it can be used as a component hardware for a highly reliable control system.