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Reliability, IEEE Transactions on

Issue 3 • Date Aug 1988

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Displaying Results 1 - 15 of 15
  • k-out-of-m system availability with minimum-cost allocation spares

    Publication Year: 1988 , Page(s): 287 - 292
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (448 KB)  

    An optimization method for determining the number of spare units that should be allocated to a k-out-of-m system to minimize the system-spares cost yet attain the specified system availability is presented. The objective function for optimization is a nonlinear integer type. The optimization method is a variation of the simplex search technique used for continuous functions. The optimization problem is cast in a form that minimizes the system-spares cost, with the required system availability as an inequality constraint. Results obtained by using the proposed optimization technique, as well as the computation time required for optimization, are compared to those for methods developed specifically for dealing with nonlinear integer problems. The method is simple, easy to implement, and yet very effective in dealing with the spare allocation problem for k-out-of-m:F systems View full abstract»

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  • Assessing throughput and reliability in communication and computer networks

    Publication Year: 1988 , Page(s): 208 - 211
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB)  

    System performance and reliability are jointly assessed for highly reliable communication/computer networks. The model assumes that at most a small number of components can be down at a time and that the average repair/replacement time of a failed component is small when compared with the average failure times of network components. The system performance is measured in terms of network throughput at steady-state operation View full abstract»

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  • Sequential imperfect preventive maintenance policies

    Publication Year: 1988 , Page(s): 295 - 298
    Cited by:  Papers (35)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (260 KB)  

    Improvement factors in hazard rate and age for a sequential preventative maintenance (PM) policy are introduced. Two imperfect PM models are analyzed: (1) PM reduces the hazard rate while it increases with the number of PMs, and (2) PM reduces the age. The PM is done at intervals xk (k=1,2, . . . , N) and is imperfect. The optimal policies to minimize the mean cost rates are discussed. The optimal PM sequences {xk} are computed for a Weibull distribution View full abstract»

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  • Reliability analysis using Weibull lifetime data and expert opinion

    Publication Year: 1988 , Page(s): 340 - 347
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (488 KB)  

    An approach to the analysis of failure data from a Weibull distribution is presented. The approach features incorporation of expert opinion and of the author's opinion on the expertise of the experts in the analysis. The use of Laplace approximation results in formulas which are easy to compute View full abstract»

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  • Network reliability with arc failures and repairs

    Publication Year: 1988 , Page(s): 268 - 273
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (364 KB)  

    Arc repair probabilities are incorporated into network calculations for directed networks with independent arc failures. A discrete-time Markov chain with one absorbing state is constructed for the problem. The transition probability matrix is used to determine the probability of source-to-sink conductivity in a given time interval, the mean time to source-to-sink connectivity, the fraction of time a node is blocked, and the fraction of time the network is blocked (disconnected). Blockage probabilities aid in repair-crew allocation to the nodes of the network View full abstract»

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  • Failure rate of a cold- or hot-spared component with a lognormal lifetime

    Publication Year: 1988 , Page(s): 299 - 307
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (652 KB)  

    Graphical and asymptotic representations are derived for the failure rates of cold-spared and hot-spared assemblies consisting of a pair of statistically independent components with identical, lognormally distributed lifetimes. Application to a laser regenerator in an undersea optical-communication cable is discussed. For the lognormal-lifetime distribution, which applies to many solid-state components with predictive screening, redundancy causes a large increase in reliability. An symptotic expansion is presented along with graphs to compute the reduction in the failure rate due to cold and hot sparing View full abstract»

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  • Reliability evaluation in power-system transmission planning: practical considerations

    Publication Year: 1988 , Page(s): 274 - 279
    Cited by:  Papers (5)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (432 KB)  

    In the reliability algorithm based on the maximum-flow minimum-cut technique together with the decomposition principle, the generation of the state space for purposes of classification requires a large amount of memory. A state-space truncation algorithm which reduces the number of states while maintaining accuracy within specific limits is presented. The reliability algorithm is developed further to produce: (1) all possible loss-of-load levels and their associated probabilities, and (2) the system reliability indices and their sensitivities with respect to element capacities. This algorithm has been applied to a small test system, and to the IEEE reliability test system View full abstract»

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  • A simple model for fatigue life

    Publication Year: 1988 , Page(s): 314 - 322
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (592 KB)  

    A simple model to handle fatigue-life length problems is discussed. The characteristic property of the model is that it combines the Palmgren-Miner rule with time invariance. The model is applied to situations with both random strength and random load. The randomness in the life is generated by the random strength and not by the random load. The only property of the random load that affects the life is its damage intensity, which is independent of the particular realization in the ergodic-load case. The damage intensity is even independent of the distribution of the random function, provided its level-crossing intensity is known. Particular attention is given to simple random strength models. In general, the exhaustion density is a random function, but in the simple models the only randomness that appears in the strength is either randomness in the time scale or randomness in the amplitude scale. The model is well-suited for comparative calculations under different load conditions, since it connects fatigue life for random loads to fatigue life for periodically oscillating loads, which is usually measured in experiments View full abstract»

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  • On computing MTBF for a k-out-of-n:G repairable system

    Publication Year: 1988 , Page(s): 312 - 313
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (128 KB)  

    It is often necessary to calculate the MTBF (mean time between failures) quickly in order to make timely design decisions. An important system for which such calculations must be made is a k-out-of- n:G parallel system with unlimited repair and exponential interfailure and repair times at the unit level. Although a general formula is known, it is not easily remembered or derived. A method for deriving a formula for MTBF in this situation that is easily reproduced quickly by remembering a few simple concepts is presented View full abstract»

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  • Transient-fault analysis for retry techniques

    Publication Year: 1988 , Page(s): 323 - 330
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (600 KB)  

    The problem of system recovery from transient faults is addressed using retry techniques. A probabilistic model for the activity of faulty periods, and a fault analysis to derive the optimum retry period are presented. Distribution functions are derived to represent the case of false alarm, where a transient fault is flagged as permanent, and the case of a miss because too many faults coexist, overcoming the checker's capability to detect them. These derivations are compared with the results of a simulation program representing the model. Other factors influencing the value of the retry period are discussed View full abstract»

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  • Optimal wear-limit replacement with wear-dependent failures

    Publication Year: 1988 , Page(s): 293 - 294
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (148 KB)  

    The optimal wear-limit for preventive replacement for an item with wear-dependent failure rate is derived by minimizing the long-run total mean cost rate. The generic term wear connotes any type of degradation that accumulates through use and is observed continuously in time. The optimal strategy has the same form as the age replacement policy View full abstract»

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  • Schemes of dynamic redundancy for fault tolerance in random access memories

    Publication Year: 1988 , Page(s): 331 - 339
    Cited by:  Papers (1)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (844 KB)  

    For large memory capacities, stand-by systems usually need a considerable amount of redundant hardware, not only because of the spare components, but for storing fault conditions and for carrying out the necessary reconfiguration. As alternatives, two methods of implementing fault tolerance by means of dynamic redundancy in random-access memories are proposed which allow the treatment of memory-chip faults at the interface of the memory. The memory reliability for both approaches is estimated by a simple model. These methods improve the reliability considerably compared to conventional memory fault tolerance methods, and the size of the units of reconfiguration can be tailored to the demands of the system user View full abstract»

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  • A practical implementation of the factoring theorem for network reliability

    Publication Year: 1988 , Page(s): 259 - 267
    Cited by:  Papers (23)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (804 KB)  

    The factoring theorem is a simple tool for determining the K -terminal reliability of a network, i.e. the probability that a given set K of terminals in the network are connected to each other by a path of working edges. An implementation of an algorithm which uses the factoring theorem, in conjunction with degree-1 and degree-2 vertex reductions, to determine the reliability of a network is presented. Networks treated have completely reliable nodes and have edges which fail statistically and independently with known probabilities. The reliability problem is to determine the probability that all nodes in a designated set of nodes can communicate with each other. Such an implementation of the factoring theorem can be incorporated in a small, stand-alone program of about 500 lines of code. A program of this type requires little computer memory and is ideally suited for microcomputer use View full abstract»

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  • A note on convergence problems in numerical techniques for accelerated life-testing analysis

    Publication Year: 1988 , Page(s): 348 - 349
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (148 KB)  

    Numerical solutions to determine maximum-likelihood estimators of parameters use a variety of techniques such as Newton-Raphson, Hook-Jeeves, and steepest ascent. All of these methods are subject to convergence difficulties that frequently occur in simulation studies. A tested and tried transformation for a variety of likelihood functions, and for the above mentioned numerical techniques, is introduced. The transformation is recommended for situations in which convergence difficulties are encountered View full abstract»

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  • Replacement vs. repair of failed components for a system with a random lifetime

    Publication Year: 1988 , Page(s): 280 - 286
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (448 KB)  

    The computation of a variety of reliability measures for a system that is observed over a random time horizon is examined. This time interval, which can correspond to the system mission, the system lifetime, etc., is assumed to be distributed as a random variable of phase type. Models are developed that aid a decision-maker to choose among the actions of replace, repair, or do nothing, whenever a system component fails, under several assumptions concerning the amount of information available to the decision-maker. In addition, a policy of replacement after a fixed number of repairs is examined. An example computation of several reliability measures and the application of a cost model are included to illustrate the tractability of the results and their usefulness in design decisions View full abstract»

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Aims & Scope

IEEE Transactions on Reliability is concerned with the problems involved in attaining reliability, maintaining it through the life of the system or device, and measuring it.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Way Kuo
City University of Hong Kong