摘要:

AbstractA one‐period inventory model where supply is a random variable with mean proportional to the quantity ordered has been considered. Under new better than used in expectation assumption on the supply variable, a strategy which maximizes a minimum profit has been suggested. An estimate for this maximin order quantity whenever the (customer) demand distribution is unknown has been proposed and almost sure convergence of this estimate to its true value with increasing sample size has been establishe

ISSN:0894-069X    

DOI:10.1002/1520-6750(198704)34:2<151::AID-NAV3220340202>3.0.CO;2-G

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

年代:1987

数据来源: WILEY

摘要:

AbstractIn this article a new heuristic procedure is proposed. This procedure makes use of surrogate duality in solving multiconstraint knapsack problems. Computational effort involved in the procedure is bounded by a polynomial in the number of variables. Extensive computational testing indicates that the procedure generates good feasible solutions regardless of the problem structure. In 98% of the problems solved, the solution generated by the heuristic was within 1% of the optimal solution. This procedure was also tested against other heuristics and was found to compare favorably.

ISSN:0894-069X    

DOI:10.1002/1520-6750(198704)34:2<161::AID-NAV3220340203>3.0.CO;2-A

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

年代:1987

数据来源: WILEY

摘要:

AbstractCalculations for large Markovian finite source, finite repair capacity two‐echelon repairable item inventory models are shown to be feasible using the randomization technique and a truncated state space approach. More complex models (involving transportation pipelines, multiple‐item types and additional echelon levels) are also conside

ISSN:0894-069X    

DOI:10.1002/1520-6750(198704)34:2<173::AID-NAV3220340204>3.0.CO;2-2

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

年代:1987

数据来源: WILEY

摘要:

AbstractDisruptions in the production process can have a serious impact on production costs. Most of the previous literature which addresses the cost impact of production breaks attributes the observed increase in costs solely to “loss of learning.” We develop a mathematical model which implies that breaks in the unit learning curve can occur because of a production break, even under the assumption of no forgetting. In such cases, increases in unit cost can be caused by decreasing returns as the amount of time available to meet the delivery schedule decreases due to the production br

ISSN:0894-069X    

DOI:10.1002/1520-6750(198704)34:2<199::AID-NAV3220340205>3.0.CO;2-O

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

年代:1987

数据来源: WILEY

摘要:

AbstractProcedures are developed for numerically calculating the waiting‐time distribution for bulk arrival, bulk service queues operated under a vehicle‐cancellation or a vehicle‐holding strategy, as well as for queues where vehicles depart regardless of the length of the queue. Experiments indicate that the mean and variance of the calculated distribution agree very closely with analytical expressions obtained from transforms. The results can be used to study the service reliability of different dispatching strategies. Alternatively, the results may be used to evaluate simpler approximations for the higher mo

ISSN:0894-069X    

DOI:10.1002/1520-6750(198704)34:2<207::AID-NAV3220340206>3.0.CO;2-C

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

年代:1987

数据来源: WILEY

摘要:

AbstractThep‐center problem involves finding the best locations forpfacilities such that the furthest amongnpoints is as close as possible to one of the facilities. Rectangular (sometimes called rectilinear, Manhattan, orl1) distances are considered. AnO(n)algorithm for the 1‐center problem, anO(n)algorithm for the 2‐center problem, and anO(nlogn) algorithm for the 3‐center problem are given. Generalizations to generalp‐center problems are also

ISSN:0894-069X    

DOI:10.1002/1520-6750(198704)34:2<229::AID-NAV3220340207>3.0.CO;2-1

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

年代:1987

数据来源: WILEY

摘要:

AbstractThe problem of estimation of the common scale parameter of two Pareto distributions with unknown and unequal shape parameters in censored samples is considered. The uniformly minimum variance unbiased estimator (UMVUE) is given along with the UMVUE of its variance.

ISSN:0894-069X    

DOI:10.1002/1520-6750(198704)34:2<235::AID-NAV3220340208>3.0.CO;2-#

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

年代:1987

数据来源: WILEY

摘要:

AbstractI examine the problem of determining inventory stockage levels and locations of different parts in a multiechelon system. This stockage problem is complicated by parts commonality—each part may be used by several different end items. Stockage levels and locations of each part affect the availability of end items that use the part, since an end item will be out of service if it requires a part that is not available. Of course, if the part is available at another nearby location, then the end item will be out of service for a shorter period of time. An essential feature of any model for this problem is constraints on operational availability of the end items. Because these constraints would involve nonconvex functions if the stockage levels were allowed to vary continuously, I formulate a 0–1 linear optimization model of the stockage problem. In this model, each part can be stocked at any of a number of prespecified levels at each echelon. The model is to minimize stockage cost of the selected items subject to the end‐item availability constraints and limits on the total weight, volume, and number of different parts stocked at each echelon. Advantages and disadvantages of different Lagrangian relaxations and the simplex method with generalized upper‐bounding capability are discussed for solving this stockag

ISSN:0894-069X    

DOI:10.1002/1520-6750(198704)34:2<239::AID-NAV3220340209>3.0.CO;2-T

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

年代:1987

数据来源: WILEY

摘要:

AbstractThe class of functions expressed as linear (not necessarily convex) combinations of negative exponential functions is dense in the set of all square integrable functions on the nonnegative reals. Because of this and resultant mathematical properties, linear combinations of exponential densities have excellent potential for wide application in stochastic modeling. This work documents the development and testing of a practical procedure for maximum‐likelihood estimation for these generalized exponential mixtures. The algorithm offered for the problem is of the Jacobi type and guarantees that the result will provide a legitimate probability function of the prescribed type. Extensive testing has been performed and results are very favorable: convergence is rapid and the use of computer resources rather limite

ISSN:0894-069X    

DOI:10.1002/1520-6750(198704)34:2<251::AID-NAV3220340210>3.0.CO;2-K

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

年代:1987

数据来源: WILEY

摘要:

AbstractThis article deals with the problem of selecting thetbest ofnindependent and identically distributed random variables which are observed sequentially with sampling costcper unit. Assume that a decision for acceptance or rejection must be made after each sampling and that the reward for each observation with valuexis given bypx ‐ c, wherepis 1 if the observation is accepted, or 0 otherwise. The optimal decision procedure (strategy) for maximizing the total expected reward is obtained. The critical numbers which are necessary to carry out the optimal decision procedure is presented by two recursive equations. The limit values of the critical numbers and the expected sample size are also studie

ISSN:0894-069X    

DOI:10.1002/1520-6750(198704)34:2<281::AID-NAV3220340211>3.0.CO;2-8

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

年代:1987

数据来源: WILEY