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291.
After first formulating the problem of the Marine Environmental Protection program of the Coast Guard as a multiple-objective linear program, we investigate the applicability and limitations of goal programming. We point out how the preemptive goal-programming approach is incompatible with utility preferences. Then we observe the tendency of optimal solutions for standard linear goal programs to occur at extreme points. We also note problems of more general approaches, such as dealing with additively separable approximations to preferences. 相似文献
292.
We consider the problem of maximizing the number of on‐time jobs on two uniform parallel machines. We show that a straightforward extension of an algorithm developed for the simpler two identical parallel machines problem yields a heuristic with a worst‐case ratio bound of at least . We then show that the infusion of a “look ahead” feature into the aforementioned algorithm results in a heuristic with the tight worst‐case ratio bound of , which, to our knowledge, is the tightest worst‐case ratio bound available for the problem. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006 相似文献
293.
A single machine scheduling problem in which both the processing times and due-dates of the jobs awaiting servicing are random variables is analyzed. It is proved that the properties of the shortest processing time rule and the due-date rule which are known for the deterministic situation also hold in the probabilistic environment when they are suitably, and reasonably, refined for this context. 相似文献
294.
295.
Edward J. Dudewicz 《海军后勤学研究》1970,17(1):69-78
Suppose that observations from populations π1, …, πk (k ≥ 1) are normally distributed with unknown means μ1., μk, respectively, and a common known variance σ2. Let μ[1] μ … ≤ μ[k] denote the ranked means. We take n independent observations from each population, denote the sample mean of the n observation from π1 by X i (i = 1, …, k), and define the ranked sample means X [1] ≤ … ≤ X [k]. The problem of confidence interval estimation of μ(1), …,μ[k] is stated and related to previous work (Section 1). The following results are obtained (Section 2). For i = 1, …, k and any γ(0 < γ < 1) an upper confidence interval for μ[i] with minimal probability of coverage γ is (? ∞, X [i]+ h) with h = (σ/n1/2) Φ?1(γ1/k-i+1), where Φ(·) is the standard normal cdf. A lower confidence interval for μ[i] with minimal probability of coverage γ is (X i[i] – g, + ∞) with g = (σ/n1/2) Φ?1(γ1/i). For the upper confidence interval on μ[i] the maximal probability of coverage is 1– [1 – γ1/k-i+1]i, while for the lower confidence interval on μ[i] the maximal probability of coverage is 1–[1– γ1/i] k-i+1. Thus the maximal overprotection can always be calculated. The overprotection is tabled for k = 2, 3. These results extend to certain translation parameter families. It is proven that, under a bounded completeness condition, a monotone upper confidence interval h(X 1, …, X k) for μ[i] with probability of coverage γ(0 < γ < 1) for all μ = (μ[1], …,μ[k]), does not exist. 相似文献
296.
The MAD model presents a mathematic treatment of the relationship between aircraft reliability and maintainability, system manning and inspection policies, scheduling and sortie length, and aircraft downtime. Log normal distributions are postulated for subsystem repair times and simultaneous repair of malfunctions is assumed. The aircraft downtime for maintenance is computed with the distribution of the largest of k log normal distributions. Waiting time for maintenance men is calculated either by using a multiple-channel queuing model or by generating the distribution of the number of maintenance men required and comparing this to the number of men available to determine the probability of waiting at each inspection. 相似文献
297.
Peter J. Kalman 《海军后勤学研究》1970,17(4):547-553
In this paper a stochastically constrained replacement model is formulated. This model determines a sequence of replacement dates such that the total “current account” cost of all future costs and capital expenditures over an infinite time horizon for the n initial incumbent machines is minimized subject to the constraints that an expected number of machines are in a chosen utility class at any point in time. We then indicate one possible solution method for the model. 相似文献
298.
A fundamental unsolved problem in the programming area is one in which various activities have fixed charges (e.g., set-up time charges) if operating at a positive level. Properties of a general solution to this type problem are discussed in this paper. Under special circumstances it is shown that a fixed charge problem can be reduced to an ordinary linear programming problem. 相似文献
299.
300.
J. J. Lagemann 《海军后勤学研究》1967,14(1):89-99
A new method has been developed f o r solving the transportation problem. This method is a modification and a generalization of the method for solving the multiple assignment problem developed by Dr. A. J. Hoffman and Dr. H. M. Markowitz. This method is of interest for several reasons. In the first place it is significantly different from all other methods for solving the trans -portation problem known to the author. Secondly, it is moderately simple touse and understand. Thirdly, and perhaps most important, it has proved to be very adaptable tri high-speed computer operations. It is now being used by several branches of the armed services. 相似文献