摘要:

AbstractA target is moving along a straight‐line path. Random portions of the path might be invisible to the hunter (in shadow). Shooting trials are conducted only along the visible segments of the path. An algorithm for the numerical determination of the survival probability of the target is developed. This algorithm is based on the distribution of shadow length, which is also developed. © 1994 John Wiley&Sons, I

ISSN:0894-069X    

DOI:10.1002/1520-6750(199410)41:6<689::AID-NAV3220410602>3.0.CO;2-5

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

年代:1994

数据来源: WILEY

摘要:

AbstractMost ammunition is produced long before its ultimate consumption and stored in a series of different depots for a considerably long period of time. During storage, the quality of the ammunition stockpile deteriorates proportionally to the condition of the depots. We view different conditions associated with a series of depots as step stress. A random effects logistic regression model is employed to predict the quality of ammunition stockpile in terms of the routing information such as a series of locations and duration of storage of ammunition lots. The resultant prediction model can be used to determine the appropriate time for reorder or renovation of ammunition before the quality becomes substandard. An example is given to illustrate the implementation procedure of the prediction model suggested in this article. © 1994 John Wiley&Sons, Inc

ISSN:0894-069X    

DOI:10.1002/1520-6750(199410)41:6<707::AID-NAV3220410603>3.0.CO;2-R

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

年代:1994

数据来源: WILEY

摘要:

AbstractResource allocation problems consider the allocation of limited resources among numerous competing activities. We address an allocation problem with multiple knapsack resource constraints. The activities are grouped into disjoint sets. Ordering constraints are imposed on the activities within each set, so that the level of one activity cannot exceed the level of another activity in the same set. The objective function is of the minimax type and each performance function is a nonlinear, strictly decreasing and continuous function of a single variable. Applications for such resource allocation problems are found, for example, in high‐tech industries confronted with large‐scale and complex production planning problems. We present two algorithms to solve the allocation problem with ordering constraints. The first one uses characterization of the optimal decision variables to apply a search method. The second algorithm solves a sequence of problems, each in the format of the original problem without ordering constraints. Whereas the computational effort of the first algorithm depends on the desired degree of accuracy even for linear performance functions, the effort of the latter algorithm is polynomial for certain classes of performance functions. © 1994 John Wiley&Sons,

ISSN:0894-069X    

DOI:10.1002/1520-6750(199410)41:6<719::AID-NAV3220410604>3.0.CO;2-J

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

年代:1994

数据来源: WILEY

摘要:

AbstractThis article considers the problem of estimating parameters of the demand distribution in lost sales inventory systems. In periods when lost sales occur demand is not observed; one knows only that demand is larger than sales. We assume that demands form a sequence of IID normal random variables, which could be a residual demand process after filtering out seasonality and promotional nonstationarities. We examine three estimators for the mean and standard deviation: maximum likelihood estimator, BLUE (best linear unbiased estimator), and a new estimator derived here. Extensive simulations are reported to compare the performance of the estimators for small and large samples and a variety of parameter settings. In addition, I show how all three estimators can be incorporated into sequential updating routines. © 1994 John Wiley&Sons, Inc

ISSN:0894-069X    

DOI:10.1002/1520-6750(199410)41:6<739::AID-NAV3220410605>3.0.CO;2-A

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

年代:1994

数据来源: WILEY

摘要:

AbstractWe demonstrate here how recent advances in the study of discrete‐event stochastic systems provide fruitful results for the modeling, analysis, and design of manufacturing systems. We consider a multistagemake‐to‐stocksystem where outputs from the final stage are used to satisfy customer demands. We address the problem of finding the appropriate trade‐off between reduced order waiting time and increased process speeds. Using the idea ofinfinitesimal perturbation analysis(IPA), we establish a simple procedure wheresample‐path derivativescan be obtained along an arbitrary sample path. Under suitable conditions, we demonstrate that these derivative estimators areunbiasedandstrongly consistentand can be used in a classical stochastic optimization scheme to solve the problem. The role of continuity and convexity on the validity of the estimator is also addressed. Although the focus of this article is not to solve for the optimal solution, we provide a theoretical justification for such a pursuit. The approach is appealing as it is numerically stable, easy to implement, and can be extended to other system performance measures. © 1994 John Wiley

ISSN:0894-069X    

DOI:10.1002/1520-6750(199410)41:6<759::AID-NAV3220410606>3.0.CO;2-1

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

年代:1994

数据来源: WILEY

摘要:

AbstractSuppose that a multicomponent reliability system earns revenue while it is working and that it has a finite number of possible failure states (defined as states in which it ceases to work), each with a known prior probability. When the system stops working its components can be inspected one at a time, and, if necessary, replaced or repaired, until the system is restored to its original (operating) state. Inspections (as well as replacements or repairs) are time consuming and expensive. An optimal adaptive inspection strategy for examining and fixing the components of a failed system restores it as efficiently as possible, taking into account the opportunity costs due to lost revenue while the system remains failed as well as the costs and times required for inspections. This article presents exact and heuristic procedures for constructing optimal adaptive strategies fork‐out‐of‐nand general coherent systems. Average revenue per unit time is taken as the maximand for most of the article, but characterizations of optimality are also obtained for series systems in the case of discounted return over an infinite planning horizon. © 1994 John Wiley&Son

ISSN:0894-069X    

DOI:10.1002/1520-6750(199410)41:6<771::AID-NAV3220410607>3.0.CO;2-0

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

年代:1994

数据来源: WILEY

摘要:

AbstractA large‐scale simulation was conducted to investigate the statistical properties and the suitability of an estimator that estimates the coordinates of a three‐dimensional source, according to the angles at which several observers view the source. The estimator uses a heuristical averaging method of estimates obtained from the solution of six two‐dimensional problems that utilize line‐to‐point transformations. The estimator was found to be approximately unbiased with low standard deviations for normal error distributions. An effective and easy‐to‐use forecasting formula was developed to forecast the parameters of the distributions of the estimates. © 1994 John W

ISSN:0894-069X    

DOI:10.1002/1520-6750(199410)41:6<789::AID-NAV3220410608>3.0.CO;2-N

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

年代:1994

数据来源: WILEY

摘要:

AbstractWe consider the problem of scheduling a set of jobs on a single machine where the release time of a job is related to the amount of resource consumed. The objective is to minimize the total resource consumption with a control on the completion times of the jobs. Four different variants of the problem are studied: (i) minimization of the total resource consumption subject to a common deadline for all jobs, (ii) minimization of the total resource consumption subject to a constraint on the total completion time of the jobs, (iii) minimization of the weighted total resource consumption and maximum job completion time, and (iv) minimization of the weighted total resource consumption and the total job completion time. We compare the common resource consumption function with the function where the resource consumed is proportional to the processing time of the job. We show that these two different resource consumption functions can give rise to very different solution methods and different computational complexities for the problem. © 1994 John Wiley&Sons, Inc

ISSN:0894-069X    

DOI:10.1002/1520-6750(199410)41:6<807::AID-NAV3220410609>3.0.CO;2-8

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

年代:1994

数据来源: WILEY

摘要:

AbstractAn initial point search game on a weighted graph involves a searcher who wants to minimize search and travel costs seeking a hider who wants to maximize these costs. The searcher starts from a specified vertex 0 and searches each vertex in some order. The hider chooses a nonzero vertex and remains there. We solve the game in which the graph is a simple tree, and use this solution to solve a search game on a tree in which each branch is itself a weighted graph with a certain property, and the searcher is obliged to search the entire branch before departing. © 1994 John Wiley&Sons, Inc

ISSN:0894-069X    

DOI:10.1002/1520-6750(199410)41:6<821::AID-NAV3220410610>3.0.CO;2-Y

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

年代:1994

数据来源: WILEY

摘要:

AbstractWe consider a generalization of the 0‐1 knapsack problem called the set‐union knapsack problem (SKP). In the SKP, each item is a set of elements, each item has a nonnegative value, and each element has a nonnegative weight. The total weight of a collection of items is given by the total weight of the elements in the union of the items' sets. This problem has applications to data‐base partitioning and to machine loading in flexible manufacturing systems. We show that the SKP remains NP‐hard, even in very restricted cases. We present an exact, dynamic programming algorithm for the SKP and show sufficient conditions for it to run in polynomial time. © 1994 John Wiley&S

ISSN:0894-069X    

DOI:10.1002/1520-6750(199410)41:6<833::AID-NAV3220410611>3.0.CO;2-Q

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

年代:1994

数据来源: WILEY