摘要:

AbstractA computationally simple method for obtaining confidence bounds for highly reliable coherent systems, based on component tests which experience few or no failures, is given. Binomial and Type I censored exponential failure data are considered. Here unknown component unreliabilities are ordered by weighting factors, which are firstly presumed known then sensitivity of the confidence bounds to these assumed weights is examined and shown to be low.

ISSN:0028-1441    

DOI:10.1002/nav.3800250202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractA system whose configuration (block diagram or fault tree) changes during consecutive time periods (phases) performs a “phased mission.” Recently, Esary and Ziehms have shown that any multiphase mission can be transformed into an equivalent, synthetic, single‐phase system, and thus that the phased mission problem can in principle be solved by standard reliability methods. We employ these ideas here to study approximations to mission reliability and to develop an algorithm which may be of practical interest. In addition, we extend the reliability calculus of Rubinstein, and Esary and Hayne, based on an approximate hazard transform, to phased missions, and we show how this extended calculus can be used in situations where phases are not of known fixed dur

ISSN:0028-1441    

DOI:10.1002/nav.3800250203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractInspection models deal with operating systems whose stochastic failure is detected by observations carried out intermittently. The current communication deals with systems in whichN+1levels of quality can be diagnosed. Optimal policies leading to minimal loss are developed, while the system's distribution is represented by an (N+ 1)‐state semi‐markov process. Based on previous studies of the authors, relative efficiencies of the proposed checking policies are ascertained, by comparison with the loss sustained if discrimination of quality by intermediate levels is disregarded and by viewing the system as one which is either good or failed. Various models are treated where checking, truncated checking, and monitoring policies optimize loss per cycle, per unit of time and per unit of good time. Numerical examples are gi

ISSN:0028-1441    

DOI:10.1002/nav.3800250204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractIn an earlier paper, it was shown that under certain conditions, if the number of classes in a multinomial distribution increases as the number of trials increases, the probabilities assigned to arbitrary regions by the multinomial distribution are close to the probabilities assigned by the distribution of slightly rounded‐off normal random variables. A different method of studying the approximation of the multinomial distribution by a normal distribution is to use the multivariate Berry‐Esseen bound. In this paper, these two methods are compared, particularly with respect to the class of multinomial distributions for which the bounds on the error remain use

ISSN:0028-1441    

DOI:10.1002/nav.3800250205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractAn algorithm for calculating the probabilities of a summed multinomial density function which is recursive withn(the number of trials) is presented. Having application in inspector error models for auditing and quality control problems with Cartesian product structures, the algorithm is discussed in the context of computing optimal economic sampling plans. Computational experience with the algorithm is presented.

ISSN:0028-1441    

DOI:10.1002/nav.3800250206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractWith constant firing, metal fatigue produces cracks in a gun barrel. The useful life of the barrel comes to an end when a crack develops to a critical size. The theory of Fracture Mechanics suggests a formula for crack size growth rate. This formula can be used to determine the life of a barrel, depending on the initial and critical crack sizes and other factors. The initial crack size turns out to be a dominant factor. Unfortunately, accurate measurements are not generally available on the initial crack size. In this paper, we propose a simple probability model for the initial crack size and this, in turn, leads to a probability distribution of the life of the barrel. This last distribution is the well‐known exponential distribution with a location shift. The simplicity of this final result is one of the factors that make the model appealin

ISSN:0028-1441    

DOI:10.1002/nav.3800250207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractA new approach is presented for analyzing multiple‐attribute decision problems in which the set of actions is finite and the utility function is additive. The problem can be resolved if the decision makers (or group of decision makers) specifies a set of nonnegative weights for the various attributes or criteria, but we here assume that the decision maker(s) cannot provide a numerical value for each such weight. Ordinal information about these weights is therefore obtained from the decision maker(s), and this information is translated into a set of linear constraints which restrict the values of the weights. These constraints are then used to construct a polytopeWof feasible weight vectors, and the subsetsHi(polytopes) ofWover which each actionaihas the greatest utility are determined. With the Comparative Hypervolume Criterion we calculate for each action the ratio of the hypervolume ofHito the hypervolume ofWand suggest the choice of an action with the largest such ratio. Justification of this choice criterion is given, and a computational method for accurately approximating the hypervolume ratios is described. A simple example is provided to evaluate the efficiency of a computer code developed to implement the metho

ISSN:0028-1441    

DOI:10.1002/nav.3800250208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractThe loading problem we consinder is to assign a set of discrete objects, each having a weight, to a set of boxes, each of which has a capacity limit, in such a way that every object is assigned to a box and the number of boxes used is minimized.A characterization of the assignments is offered and used to develop a set of rules for generating nonredundant assignments. The rules are incorporated into an implicit enumeration algorithm. The algorithm is tested against a very good heuristic. Computational experience shows that the algorithm is highly efficient, solving problems of up to 3600 0‐1 variables in a CPU secon

ISSN:0028-1441    

DOI:10.1002/nav.3800250209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractProposed is a Heuristic Network (HN) Procedure for balancing assembly lines. The procedure uses simple heuristic rules to generate a network which is then traversed using a shortest route algorithm to obtain a heuristic solution. The advantages of the HN Procedure are: a) it generally yields better solutions than those obtained by application of the heuristics, and b) sensitivity analysis with different values of cycle time is possible without having to regenerate the network. The rationale for its effectiveness and its application to problems with paralleling are presented. Computational experience with the procedure on up to 50 task test problems is provided.

ISSN:0028-1441    

DOI:10.1002/nav.3800250210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractA pseudo‐monotonic interval program is a problem of maximizingf(x)subject tox ε X = {x ε Rn| a

ISSN:0028-1441    

DOI:10.1002/nav.3800250211

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY