• Journal of the Korea Society for Simulation
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• v.9 no.2
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• pp.51-61
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• 2000

In recent years, significant advances in computers and communication technologies have made multimedia services feasible. As a result, various queueing models and cost models on architecture and data placement for multimedia server have been proposed. However, most of these models do not evaluate dependability of systems. In the design phase of a system, simulation is an important experimental means for performance and dependability analysis. Fault injection simulation has been used in evaluation of dependability metric. In this paper, we develop fault injection simulation model to analyze dependability of parallel video servers. In addition, we evaluate reliability and MTTF(Mean Time To Failure) of systems by using the simulator.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.347-358
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• 2001

In this paper, we apply NHPP model example to s/w process in order to get to know s/w reliability. The test is constructed by a test zig of commercial product loaded real embedded system s/w. It is established to s/w reliability prediction and estimation of real-time embedded system s/w. It is computed the prediction value of cumulative failures, the failure intensity, the reliability and the estimation value of MTTF, Failure Rate. To the more realization of high reliability in the real-time embedded system s/w, if the embedded system s/w is ensured to the test coverage and constructed to stable s/w process ＆ operating system, we can improve the performance and the reliability characteristic of the real-time embedded system s/w.

• Journal of the Korean Society of Safety
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• v.24 no.6
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• pp.150-156
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• 2009

The oil pressure switch(OPS) for automobile is very important part to prevent an overheated engine and other problems by checking the operation of an engine oil system and displaying oil signs on a dashboard. OPS is the part that receives various stress caused by temperature, vibration, and corrosion in an engine room. Regarding existing steel OPS cases, there occur field errors due to the rust, and much concern comes from the low anticorrosion caused by CR6+ Free according to the restrictions of heavy metals. Therefore, the study analyzed average life, the failure rate, and reliability through the tests of performance according to temperature changes, mechanical strength, and run-test in order to confirm if the use of the oil pressure switch with Al of anti-corrosion can improves the reliability, instead of the existing steel products.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.3
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• pp.414-416
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• 2013

As the usage of the electric power train increases, the importance of the control network between the electric control devices grows. IEC proposed a revision of IEC-61375, a standard of the networking among electric devices within a train, to adopt Ethernet as a backbone of train network. This paper performed the reliability analysis of three configurations of Ethernet-based networking within a electric power train that are recommended in IEC-61375 standard. The analysis results show that MTTF(mean time to failure) of the redundant configuration is 20,086 hours, which is a about 3 times longer than the linear configuration.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.375-377
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• 1998

This paper shows two models of the TMR system- fail passive system - having a fault tolerant system characteristic used in airplane and railway system. We design the single system, single-voter TMR system and triplicated voter TMR system based on MC68000 and calculate the failure rate of components using MIL-SPEC-217F and evaluate the reliability and MTTF(Mean Time To Failure) of the designed systems by Markov model.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.6A
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• pp.1067-1077
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• 2001

본 논문에서는 결함의 영향을 받지 않고 동작할 수 있는 AVTMR(All Voting Triple Modular Redundancy) 시스템과 듀얼 듀플렉스(Dual-duplex) 시스템을 설계하고, 각 시스템의 평가를 통하여 RAMS(Reliability, Avaliability, Maintainability, Safety)를 비교하였다. ABTMR 시스템은 3중화된 보터(voter)를 사용하여 설계를 하였으며, 듀얼 듀플렉스 시스템은 비교기(comparator)를 이용하여 시스템을 설계하였다. 각 시스템은 버스 레벨로 데이터를 비교하도록 설계하였으며, 시스템 평가를 위해서 소자의 고장율은 MILSPEC-217F에 기반을 두고 RELEX6.0을 이용하였고, 마코브 모델(Markov model)을 이용하여 시스템의 RAMS를 평가하였다. 본 논문에서는 각 시스템을 MC68000을 기반으로 설계하여, 각각 시스템에 사용되는 비용 및 시스템이 어느 부분에서 선호될 수 있는가를 RAMS 및 MTTF(Mean Time To Failure)를 통하여 선택할 수 있는 기반을 제시하도록 나타내고 있다. 이러한 AVTMR이나 듀얼 듀플렉스 시스템(dual-duplex system)은 결함 허용 시스템(fault tolerant system)으로 인간의 생명과 직접적인 관련이 있는 고속철도 시스템이나 항공기 시스템에 적용될 수 있다.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.3
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• pp.301-311
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• 1990

A multiple controller structure consisting of a typical feedback controller and an additive redundant controller is proposed for enhancing the reliability of the control system. For the case where the main controller is chosen as a pole assignment controller with input/output measurements and the redundant controller as the Model Reference Adaptive Controller (MRAC) whose reference model is the closed-loop combination of the plant and the main controller, it is proven that the tracking error between the command input and plant output converges to zero under failure in one of the controllers or parameter perturbations of the plant, and further that the reliability measured by Mean Time To Failure (MTTF) is greater than that of the system with only a single main controller. A simulation Example is provided to illustrate reliable operation of the proposed control system against the controller failure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.11
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• pp.1279-1289
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• 1992

Fault-tolerant system in improved the reliability and safety by using hardware and software redundancy. Fault mask and detection, identification techniques are conditionally used with system's application areas. Here DMR system is operated with standby and fail-safe module method that has minimal hardware and software redundancy, then its reliablity and safety comparison is presented respectively. Also this paper proposed an effective methods of dealing with transient faults as compared system's MTTFs to transient faults tolerance capabilities of self-diagnosis program.

• 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.

• Journal of the Korean Society of Industry Convergence
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• v.12 no.4
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• pp.209-214
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• 2009

Usually, it says that reliability is failure rate achieved by required functions for some period under limited use environment conditions. The reliability can be researched by automotive part or system module and it can be affected by using environment condition, such as using atmosphere temperature and using user's behavior. Also, the time can be influence on the reliability. Recently, the oil leakage from eng oil pan was raised by customer in the field. So, there is the purpose of this paper that research predicting the reliability of eng oil pan efficiently by using reliability method described below.