ISSN:0028-1441    

DOI:10.1002/nav.3800080402

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

年代:1961

数据来源: WILEY

摘要:

AbstractThis article presents a method for predicting the downtime distribution for a new complex electronic equipment. A theoretical discussion is given which indicates that the downtime distribution for such an equipment can be represented by a lognormal function. Experimental data are shown which establish that the two‐parameter lognormal distribution function adequately describes the downtimes of a diverse group of electronic equipments. It is concluded that this analytical expression for the downtime distribution of complex electronic equipments provides the basis for a quantitative and scientific approach to the measurement and prediction of maintainability. This approach takes account of equipment maintenance characteristics and maintenance personnel capabilitie

ISSN:0028-1441    

DOI:10.1002/nav.3800080403

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

年代:1961

数据来源: WILEY

摘要:

AbstractThe problem has been considered by Isbell of determining the path that minimizes the maximum distance along the path to a line in the same plane whose distance from the starting point of the search is known, while its direction is unknown. We consider in this article the analogous problem for the search for a circle of known radius, of known distance from a starting point in its plane. It is further shown that Isbell's solution is a limiting case of the problem posed as the radius of the circle tends to infinity. The problem appears to be of some practical significance, since it is equivalent to that of searching for an object a given distance away which will be spotted when we get sufficiently close—that is, within a specific radiu

ISSN:0028-1441    

DOI:10.1002/nav.3800080404

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

年代:1961

数据来源: WILEY

ISSN:0028-1441    

DOI:10.1002/nav.3800080405

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

年代:1961

数据来源: WILEY

ISSN:0028-1441    

DOI:10.1002/nav.3800080406

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

年代:1961

数据来源: WILEY

摘要:

AbstractAn important mission of military cargo aircraft is the deployment of army equipment to areas of actual or potential warfare. The large number of vehicles required to support army forces makes weight anti cube, the traditional measures of airlift capacity, insufficient for analysis of the amount of such cargo which can be carried by various aircraft. This paper uses a representative list of army deployment cargo to investigate the capacity of alternative aircraft designs. A loading model is developed to estimate the relationship between cargo compartment dimensions and loading efficiency. The relationship between Compartment floor area and floor area of vehicles loaded is found to be remarkably stable over a large range of alternative compartment sizes. A second model is used to minimize the distribution of total weight per aircraft when the aircraft are loaded in accordance with the criteria of the first model. The resultant distributions, presented for various compartment sizes, suggest the relationship between cargo compartment and payload capacity which would be optimum for this particular mission.

ISSN:0028-1441    

DOI:10.1002/nav.3800080407

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

年代:1961

数据来源: WILEY

摘要:

AbstractProblems of inventory control for items with extremely low demand (say less than one unit per month average demand) have received relatively little attention in the literature. However, for military supply systems it is well known that an extremely large proportion of the total number of items fall into this category. The problem of designing a control system for these low demand items is therefore one of the most critical inventory management problems faced by the National Military Establishment.In the following, a single echelon, multidepot supply system is studied for low demand items having a stationary Poisson probability distribution for demand. Instantaneous information concerning inventory levels is assumed to be available. Procurement lead time is assumed to be constant as well as the time required for either of two available modes of redistribution. Items are ordered one at a time and decision rules are developed for allocation of new procurement, redistribution of stocks among the depots, and for determining system and depot stockage objectives in order to minimize the expected costs resulting from system and depot stockouts, cost of redistributing stocks among the depots, and costs of transportation from the source. The model is an extension of previous models in that redistribution costs and depot stockout costs are considered in the determination of the stockage objective for the system as a whole. When more than a single unit is on order, the allocation of a unit ready to be delivered is determined by the solution of a dynamic programming problem. When only a single unit is on order (and this is the one ready to be delivered), the optimal allocation procedure is reduced to allocating the unit to the depot which has the greatest probability of using it in a time period T + (1/λ) where T is the procurement lead time and λ the system demand rate for the ite

ISSN:0028-1441    

DOI:10.1002/nav.3800080408

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

年代:1961

数据来源: WILEY

ISSN:0028-1441    

DOI:10.1002/nav.3800080409

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

年代:1961

数据来源: WILEY

ISSN:0028-1441    

DOI:10.1002/nav.3800080410

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

年代:1961

数据来源: WILEY

ISSN:0028-1441    

DOI:10.1002/nav.3800080411

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

年代:1961

数据来源: WILEY