• International Journal of Reliability and Applications
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• 제9권2호
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• pp.141-152
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• 2008

This paper presents equations, which can be used to evaluate the failure frequency and the failure rate of a two identical component parallel redundant system in which each component can operate in its wear out period, and the failure rate of each component is exponential power distribution. The optimum maintenance interval for a two identical component parallel redundant system can be obtained using these equations. The proposed approach is presented and illustrated using several numerical examples. The optimum maintenance interval for each component in a two identical parallel redundant system will depend on factors such as: failure rate, repair and maintenance times of each component in the parallel redundant systems.

• 품질경영학회지
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• 제19권2호
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• pp.78-85
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• 1991

In this paper, an inspection and replacement policy in a redundant system is considered. It is assumed that the state of the redundant system is known by inspection. When the system is inspected, it is preventively replaced only if the number of failed units exceeds the predetermined limit. Otherwise, the system is inspected after a inspection interval which depends on the number of failed units. We obtain the optimal number of redundant units, inspection intervals and replacement limit minimizing the expected cost rate.

• 한국통신학회논문지
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• 제9권2호
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• pp.70-76
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• 1984

본 논문에서는 m개의 고장까지 극복할 수 있는 기능적 m-리던던트(Functional m-redundant)시스템을 그래프 이론에 바탕을 두고 정의하였다. 이 시스템은 리던던시를 효과적으로 이용하여 추가적인 테스트 기능없이 각 부시스템의 출력을 서로 비교함으로써 t(t$\geq$m)고장진단 가능하고 진단을 위한 시스템 정지가 필요없도록 설계되었다. 또한 이 시스템에 대한 진단 모델을 제시하였고 이 모델이 preparata의 진단 모델로 바뀌어질 수 있음을 보였으며 이를 이용하여 기능적 m-리던던트 시스템의 진단 특성을 Preparata에 의해 제시된 방법으로 해석하였다.

• 전기의세계
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• 제28권7호
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• pp.60-66
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• 1979

In this paper we deal with a hardware redundency, using the replications of an original module to enhance the reliability of the system in view of static and dynamic redundancy. As results of the study the following facts have been proved that (1) if the mission time is small (T .neq. 0.5), the effect of spare modules cannot be expected significantly, (2) for the small mission time (0.1 .neq. T .neq. 0.3) the SPR system is more reliable than the other redundant systems. In addition to above facts, it is also proved that for the large mission time (T=1), the dynamic redundant system is more reliable than the static redundant system, and that the SR system is more reliable than the HR system in the dynamic redundant system.

• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 2001년도 The Pacific Aisan Confrence On Intelligent Systems 2001
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• pp.65-70
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• 2001

We consider a hyper-redundant system that consists of many uniform units. The hyper-redundant system has many degrees of freedom and it can accomplish various tasks. Applysing the reinforcement learning to the hyper-redundant system is very attractive because it is possible to acquire various behaviors for various tasks automatically. In this paper we present a new reinforcement learning algorithm "Q-learning with propagation of motion". The algorithm is designed for the multi-agent systems that have strong connections. The proposed algorithm needs only one small Q-table even for a large scale system. So using the proposed algorithm, it is possible for the hyper-redundant system to learn the effective behavior. In this algorithm, only one leader agent learns the own behavior using its local information and the motion of the leader is propagated to another agents with time delay. The reward of the leader agent is given by using the whole system information. And the effective behavior of the leader is learned and the effective behavior of the system is acquired. We apply the proposed algorithm to a snake-like hyper-redundant robot. The necessary condition of the system to be Markov decision process is discussed. And the computer simulation of learning the locomotion is demonstrated. From the simulation results we find that the task of the locomotion of the robot to the desired point is learned and the winding motion is acquired. We can conclude that our proposed system and our analysis of the condition, that the system is Markov decision process, is valid.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.800-803
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• 2006

The Space-borne electro-optical camera system, like KOMPSAT has panchromatic redundant image channel as well as primary channel in order to increase reliability of satellite system. In most case redundant channel never been used during the whole mission period. Staggered array configuration using redundant image channel and new operation mode proposed which operates primary and redundant channel simultaneously. Without new hardware design, fast electronics and system complexity, we can get 1.414 times more fine GSD image of original system and aliasing effect which corrupt high frequency information of image can be minimized. To get the more efficiency from staggered array configuration, we introduce masked pixel CCD.

• International Journal of Reliability and Applications
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• 제3권3호
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• pp.147-154
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• 2002

In this paper, we consider the warm standby redundant system(WSRS) which is consisted of an active unit, a standby unit and a switchover device. In addition, the switchover processing is controlled by a control module. The effect of failure of the control module is taken into account to develop our reliability model for the redundant structure. For the performance evaluation of a redundant system with the function of switchover processing which is assumed to cause the increase of the failure rate of the system, some reliability indices, such as availability, average availability, reliability and steady state availability, are considered.

• 로봇학회논문지
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• 제12권2호
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• pp.194-205
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• 2017

A redundantly actuated planar 3-degree-of-freedom parallel mechanism is analyzed to show its high application potential as a haptic device. Its structure along with the closed form forward position solutions is briefly discussed. Then its geometric and kinematic characteristics via singularity analysis, the kinematic isotropy index, and the input-output force transmission ratio are investigated both for the redundantly actuated cases and for the non-redundantly actuated case. In addition, comparative joint torque simulations of the mechanism with different number of redundant actuations as well as without redundant actuation are conducted to confirm the improved joint torque distribution characteristics. Through these analyses it is shown that the geometric and kinematic characteristics of the redundantly actuated mechanism are superior to the ones of the mechanism without redundant actuation. Thus, it can be concluded that the suggested planar mechanism with redundant actuation has a very high potential for haptic device applications.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.51-52
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• 2011

• 산업경영시스템학회지
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• 제13권22호
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• pp.59-64
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• 1990

This paper is aimed to study the standby redundant system with the relay of parallel structure, by making use of the character of standby system, which reliability is higher than parallel system's if the relay has higher reliability than a certain level. By assigning the low-priced relay to the subsystem, this method increases the relay reliability, optimizes the standby redundant system reliability without violating the restrictions, and consequently reduces the cost.