摘要:

AbstractA general age replacement is introduced which incorporates minimal repair, planned and unplanned replacements, and costs which depend on time. Finite and infinite horizon results are obtained. Various special cases are considered. Furthermore, a shock model with general cost structure is considered.

ISSN:0894-069X    

DOI:10.1002/1520-6750(198810)35:5<365::AID-NAV3220350502>3.0.CO;2-#

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

年代:1988

数据来源: WILEY

摘要:

AbstractThis article develops a model for determining the optimal inspection schedule for a system which deteriorates according to a semi‐Markov process that progresses through three states: good, defective, and bad. A binary test is used, and false positives may occur. A true positive results in an action that reduces the likelihood of entering the bad state, but at most one such corrective action can occur during the lifetime of the system. Costs are associated with each inspection, each false positive, the corrective action, and the entrance into the bad state. Dynamic programming is used to compute the minimum expected cost, which is a function of the age of the system. The optimal inspection schedule is readily derived from this value function. Computational examples are provided. This model is appropriate for medical screening or for a mission where there is only one spare par

ISSN:0894-069X    

DOI:10.1002/1520-6750(198810)35:5<373::AID-NAV3220350503>3.0.CO;2-W

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

年代:1988

数据来源: WILEY

摘要:

AbstractOne seeks the optimal inspection schedule for a system whose deterioration process is a semi‐Markov process that progresses toward failure. Costs are incurred for each inspection, each false positive, and any corrective actions. There is no cost of failure, since failure is catastrophic. Two problems are analyzed. First, one wishes to minimize the expected costs subject to the constraint that the probability of failure be less than a specified value. Alternatively, one wishes to minimize the probability of failure subject to the constraint that a specified number of inspections are performed. A computational example, based on a problem of medical screening, is provide

ISSN:0894-069X    

DOI:10.1002/1520-6750(198810)35:5<393::AID-NAV3220350504>3.0.CO;2-N

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

年代:1988

数据来源: WILEY

摘要:

AbstractA counterexample is given to demonstrate that previously proposed necessary conditions for the bilevel programming problem are not correct. An interpretation of the difficulty is given by appealing to a “theorem of alternative” result presented in the original w

ISSN:0894-069X    

DOI:10.1002/1520-6750(198810)35:5<413::AID-NAV3220350505>3.0.CO;2-6

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

年代:1988

数据来源: WILEY

摘要:

AbstractIn this article we explore the properties of thediscountedtotal cost function for the economic order quantity. We show that it is convex. Furthermore, it is shown that the classical economic order quantity (based on Wilson's formula) isnot less thanthe true optimum value based on discounting. Bounds for the discounted reorder interval (or order quantity) based on average cost analysis are also provided. Furthermore, we analytically show that larger the ratio of noncapital‐related holding charges to the total holding charges, the more adverse is the effect on the accuracy of the average cost analysi

ISSN:0894-069X    

DOI:10.1002/1520-6750(198810)35:5<419::AID-NAV3220350506>3.0.CO;2-Y

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

年代:1988

数据来源: WILEY

摘要:

AbstractThis article examines the allocation of safety stock between sectors in a one‐warehouseN‐retailer distribution system which follows a (Q,R) inventory replenishment policy. In particular, the so‐called „portfolio”︁ motive for holding warehouse safety‐stock inventory is investigated. Two optimization problems involving the tradeoff between average system inventory investment and customer service, i.e., customer backorders, are considered and shown to be equivalent to a simpler optimization problem involving the tradeoff between customer service and system safety stock. Equivalence implies that the set of optimal policies for the simpler optimization problem provides all of the optimal policies for the more complex ones. This equivalence result is applied to the Deuermeyer and Schwarz (DS) model of the distribution system under study. Bounds on the set of optimal policies are provided. A heuristic for minimizing expected backorders with respect to a constraint on average system on‐hand inventory is introduced, and empirical tests described. The heuristic, which prescribeslittlewarehouse on‐hand inventory, appears to be near optimal for the DS model. A simulation study supports this „near‐zero”︁ inventory presc

ISSN:0894-069X    

DOI:10.1002/1520-6750(198810)35:5<427::AID-NAV3220350507>3.0.CO;2-U

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

年代:1988

数据来源: WILEY

摘要:

AbstractMinimax strategies are obtained for an infiltration game in which one player must move through a one‐dimensional interval defended by the other playe

ISSN:0894-069X    

DOI:10.1002/1520-6750(198810)35:5<441::AID-NAV3220350508>3.0.CO;2-R

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

年代:1988

数据来源: WILEY

摘要:

AbstractMuch research been devoted to modeling the replacement problem under incomplete state information. Almost no work has been done on the maintenance problem under incomplete information with multiple maintenance actions that may not return the system to as good as new. We model this problem and derive structural results concerning the optimal maintenance policy. For the case where the effect of maintenance actions is state dependent, we give conditions under which the optimal policy is finitely computable. Where maintenance is state independent we show a specific structure, consisting of monotonic waiting times and constant maintenance actions, to be optimal.

ISSN:0894-069X    

DOI:10.1002/1520-6750(198810)35:5<447::AID-NAV3220350509>3.0.CO;2-I

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

年代:1988

数据来源: WILEY

摘要:

AbstractIt is well‐known that any point in a convex polyhedronPcan be written as the sum of a convex combination of extreme points ofPand a non‐negative linear combination of extreme rays ofP. Grötschel, Lovász, and Schrijver gave a polynomial algorithm based on the ellipsoidal method to find such a representation for anyxinPwhenPis bounded. Here we show that their algorithm can be modified and implemented in polynomial time using the projection method or a simplex‐type algorithm : inn(2n+ 1) simplex pivots, wherenis the dimension ofx. Extension to the unbounded case is im

ISSN:0894-069X    

DOI:10.1002/1520-6750(198810)35:5<463::AID-NAV3220350510>3.0.CO;2-5

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

年代:1988

数据来源: WILEY

摘要:

AbstractThis article is concerned with the scaling variant of Karmarkar's algorithm for linear programming problems. Several researchers have presented convergence analyses for this algorithm under various nondegeneracy types of assumptions, or under assumptions regarding the nature of the sequence of iterates generated by the algorithm. By employing a slight perturbation of the algorithm, which is computationally imperceptible, we are able to prove without using any special assumptions that the algorithm converges finitely to an ε‐optimal solution for any chosen ε>0, from which it can be (polynomically) rounded to an optimum, for ε>0 small enough. The logarithmic barrier function is used as a construct for this analysis. A rounding scheme which produces an optimal extreme point solution is also suggested. Besides the non‐negatively constrained case, we also present a convergence analysis for the case of bounded variables. An application in statistics to theL1estimation problem and related computational results are pre

ISSN:0894-069X    

DOI:10.1002/1520-6750(198810)35:5<473::AID-NAV3220350511>3.0.CO;2-#

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

年代:1988

数据来源: WILEY