Department of Mathematics

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Author: search.filters.author.Shekhar, ChandraSubject: search.filters.subject.Common cause failure

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Now showing 1 - 6 of 6
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    Queueing analysis of two unreliable servers machining system with switching and common cause failure
    (Inder Science, 2013) Shekhar, Chandra
    In this paper, we analyse the performance of primary and secondary unreliable servers in a multi-component machining system. For the smooth functioning of the system, there is a provision of warm spares that may not be perfect in switching the failed operating unit. Primary server is prone to complete or partial breakdown whereas secondary server faces only complete breakdown independently or simultaneously due to common cause. The life time and repair time of the operating units, breakdown and the repair time of the servers are exponentially distributed. Various performance indices are formulated to study the behaviour of the queueing model of concerned machining system developed more significantly. By taking an illustration, the sensitivity analysis is carried out. The numerical results are summarised in tabular form and also depicted via graphs.
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    Reliability prediction of fault tolerant machining system with reboot and recovery delay
    (Springer, 2017-11) Shekhar, Chandra
    The present paper deals with the reliability analysis of fault tolerant multi-component machining system having multi-warm spares and reboot provisioning. The time-to-breakdown and repair of active/spare units and server are assumed to be exponentially distributed. The reboot process and recovery delay are also counterfeited exponentially distributed. The spectral method is adapted to compute the transient state probabilities of the system states. In order to predict the transient behavior of the system, various performance measures such as reliability function, mean-time-to-failure (MTTF), etc. have been established. To show the practicability of the developed model, we present numerical results by taking an illustration. The sensitivity of various system parameters on the reliability function and MTTF has also been examined.
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    Reliability Prediction of Computing Network with Software and Hardware Failures
    (World Scientific, 2020) Shekhar, Chandra
    In this paper, we investigate the reliability and queueing performance indices for the fault-tolerant computing network having a finite number of unreliable operating components with the provision of warm standby components. Operating and standby components are governed by dedicated software which is also prone to random failure. On failure of operating components, available standby component(s) may switch from the standby state to operating state with negligible switchover time. The switchover process may also fail due to some automation hindrance. The computing network is also subjected to common cause failure in lieu of external cause. The studied redundant fault-tolerant computing network is framed as a Markovian machine interference model with exponentially distributed inter-failure times and service times. For the reliability prediction of the computing network, various performance measures, namely, mean-time-to-failure (MTTF), reliability/availability, failure frequency, etc., have been formulated in terms of transient-state probabilities which we have obtained using the spectral method. To show the practicability of the developed model, numerical simulation has been done. Sensitivity analysis of reliability and other indices of the computing network with respect to different network parameters has been presented, and results are summarized in the tables and graphs. Finally, future scope and concluding remarks have been included.
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    Fault-tolerant redundant repairable system with different failures and delays
    (Emerald, 2020-04) Shekhar, Chandra
    The internet of things and just-in-time are the embryonic model of innovation for the state-of-the-art design of the service system. This paper aims to develop a fault-tolerant machining system with active and standby redundancy. The availability of the fault-tolerant redundant repairable system is a key concern in the successful deployment of the service system.
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    Load sharing redundant repairable systems with switching and reboot delay
    (Elsevier, 2020-01) Shekhar, Chandra
    Industry 4.0 depicts the fourth industrial revolution which prompts an insightful, associated and decentralized manufacturing. The prime viewpoint is an uninterrupted linkage between decision-makers, machines, and products during the manufacturing process empowered by the digital framework. The prime objective is to analyze the optimal design of fault-tolerant machining system with various types of machining hindrance. In this article, we investigate fault-tolerant redundant repairable machining system which is an indispensable part of computer and communication systems, manufacturing and production systems, security systems, etc. Besides the random failure of operating units and standby units, probabilistic common cause failure of the machining system, an automatic switch of the available standby unit in place of a failed operating unit with a significant switching lag is a key concern in the present study with unpredictable switching failure and reboot delay. The workload is shared in general with M operating units but continues in short mode as overload until there are at least units in the system with the degradable failure rate. Numerical simulation, comparative analyses and optimal analyses of queue characteristics are also performed significantly and the conclusion is drawn for system designers and decision-makers to develop state-of-the-art maintenance and repair policies.
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    Warm-spare provisioning computing network with switching failure, common cause failure, vacation interruption, and synchronized reneging
    (Elsevier, 2020-07) Shekhar, Chandra
    The loss of a node in a computing network, either for unplanned reasons, such as hardware failure, or planned outages, such as upgrades, can result in degraded computing network performance or loss of redundancy. To reduce this possibility, a spare node is kept powered on and visible on the network. In this paper, we study the Markovian warm-spare nodes provisioning computing network where spare nodes may also be predisposed to failure in switching from standby state to the operating state. In addition to switching failure and common cause failure, the realistic and economical maintenance server’s modified multiple working vacation policy and failed nodes’ synchronized reneging are also considered. Reliability characteristics of the computing network for I/O operations have been derived using transient-state probabilities which have been computed using the theory of the Quasi-Birth-and-Death process, Laplace transforms, Eigenvalue and Eigenvector. The critical analysis of reliability characteristics has also been done and the paper has been enriched with numerical results in the form of tables and graphs to provide a glance at the investigation. The concluding remarks and future scope have also been included.