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271.
Edward L. Hannan 《海军后勤学研究》1982,29(1):113-118
This paper investigates the two-person zero-sum multiple payoff game in which the objective is to minimize a player's total underachievement from a fixed set of goals. It is demonstrated that a previous formulation of this problem can be substantially simplified. 相似文献
272.
This paper analyzes the problem of determining desirable spares inventory levels for repairable items with dependent repair times. The problem is important for repairable products such as aircraft engines which can have very large investment in spares inventory levels. While existing models can be used to determine optimal inventory spares levels when repair times are independent, the practical considerations of limited repair shop capacity and prioritized shop dispatching rules combine to make repair times not independent of one another. In this research a simulation model of a limited capacity repair facility with prioritized scheduling is used to explore a variety of heuristic approaches to the spares stocking decision. The heuristics are also compared with use of a model requiring independent repair times (even though that assumption is not valid here). The results show that even when repair time dependencies are present, the performance of a model which assumes independent repair times is quite good. 相似文献
273.
Laurence A. Baxter 《海军后勤学研究》1982,29(3):403-410
An availability measure is the probability that a two-state system modeled by an alternating renewal process is available at one or more points or intervals. The concept of availability measures is extended to formulae for the joint prediction of availability and numbers of breakdowns (or repairs) of the system during a fixed interval. 相似文献
274.
M. Mazumdar 《海军后勤学研究》1982,29(3):411-418
We compare several competing estimates of the availability of a system which alternates between two states, “up” and “down,” in accordance with an alternating renewal process. Both interval and point estimators are compared under several special but representative situations. The comparison reaffirms the validity and robustness of the log-logistic jackknifed estimates. However, when the point estimates are compared from the intrinsic criterion of probability of concentration, the uniformly minimum variance estimate obtained for the Markov model performs very well. 相似文献
275.
Dileep R. Sule 《海军后勤学研究》1982,29(3):517-519
The paper extends the machine flow-shop scheduling problem by separating processing time into setup, processing and removal times. 相似文献
276.
This paper attempts to resolve the existing confusion concerning missing operations. Scheduling problems are classified in two groups: (i) null-continuous (NC)—comprising the problems where an optimal schedule remains optimal on replacement of arbitrarily small processing times (existing operations) with zeros (missing operations); (ii) null-discontinuous (NDC)—comprising those problems which are not null-continuous. 相似文献
277.
Preference for food in the function of the time since last consumption and total preference in the function of eating frequency are equivalent mathematical representations of attitudes governing food consumption. The observed and postulated properties of these functions imply a formal correspondence between preference maximizing and variety seeking behavior. 相似文献
278.
279.
Sarah M. Ryan 《海军后勤学研究》2003,50(2):167-183
The combination of uncertain demand and lead times for installing capacity creates the risk of shortage during the lead time, which may have serious consequences for a service provider. This paper analyzes a model of capacity expansion with autocorrelated random demand and a fixed lead time for adding capacity. To provide a specified level of service, a discrete time expansion timing policy uses a forecast error‐adjusted minimum threshold level of excess capacity position to trigger an expansion. Under this timing policy, the expansion cost can be minimized by solving a deterministic dynamic program. We study the effects of demand characteristics and the lead time length on the capacity threshold. Autocorrelation acts similarly to randomness in hastening expansions but has a smaller impact, especially when lead times are short. However, the failure either to recognize autocorrelation or to accurately estimate its extent can cause substantial policy errors. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2003 相似文献
280.
Matthew S. Goldberg 《Defence and Peace Economics》2018,29(1):44-61
AbstractIn Operation Iraqi Freedom, which ended in August 2010, nearly 3500 hostile deaths occurred among US military personnel and 32,000 more were wounded in action (WIA). More than 1800 hostile deaths occurred during Operation Enduring Freedom (in and around Afghanistan) through 2014 and about 20,000 were WIA. A larger proportion of wounded personnel survived in Iraq and Afghanistan than during the Vietnam War, but the increased survival rates were not as high as some studies have asserted. The survival rates were 90.2% in Iraq and 91.6% in Afghanistan, compared with 86.5% in Vietnam. The casualty rates varied between the conflicts in Iraq and Afghanistan and before, during, and after the respective surges. Amputation rates are difficult to measure consistently, but I estimate that 2.6% of all WIA and 9.0% of medically evacuated WIA from the Iraq and Afghanistan theaters combined resulted in the major loss of a limb. Elevated non-hostile death rates (including deaths due to accidents, illnesses, homicides, or suicides) resulted in about 220 more deaths in Iraq and about 200 more deaths in Afghanistan than would have been expected in peacetime among populations of the size deployed to those two conflicts. 相似文献