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61.
62.
Implications of a probabilistic “random walk” model of incremental sales response to advertising are developed for various timing patterns of advertising expenditures. Maximum likelihood procedures for assessing advertising effectiveness and for estimating a decay (forgetting) rate are developed and applied to artificial data of known configuration and are used to assess the impact over time of a brochure program on mail-order sales. Results are also compared to those from alternative models involving various lag patterns in advertising effects. 相似文献
63.
《Omega》2014
In recent years, the issue of water allocation among competing users has been of great concern for many countries due to increasing water demand from population growth and economic development. In water management systems, the inherent uncertainties and their potential interactions pose a significant challenge for water managers to identify optimal water-allocation schemes in a complex and uncertain environment. This paper thus proposes a methodology that incorporates optimization techniques and statistical experimental designs within a general framework to address the issues of uncertainty and risk as well as their correlations in a systematic manner. A water resources management problem is used to demonstrate the applicability of the proposed methodology. The results indicate that interval solutions can be generated for the objective function and decision variables, and a number of decision alternatives can be obtained under different policy scenarios. The solutions with different risk levels of constraint violation can help quantify the relationship between the economic objective and the system risk, which is meaningful for supporting risk management. The experimental data obtained from the Taguchi's orthogonal array design are useful for identifying the significant factors affecting the means of total net benefits. Then the findings from the mixed-level factorial experiment can help reveal the latent interactions between those significant factors at different levels and their effects on the modeling response. 相似文献
64.
A hybrid genetic algorithm/mathematical programming approach to the multi-family flowshop scheduling problem with lot streaming 总被引:3,自引:0,他引:3
This paper presents a hybrid genetic algorithm/mathematical programming heuristic for the n-job, m-machine flowshop problems with lot streaming. The number of sublots for each job and the size of sublots are directly addressed by the heuristic and setups may be sequence-dependent. A new aspect of the problem, the interleaving of sublots from different jobs in the processing sequence, is developed and addressed. Computational results from 12 randomly generated test sets of 24 problems each are presented. 相似文献
65.
In this note we present a variant of the improved algebraic method (IAM) using a duality analysis to solve linear programming (LP) problems where more insights to the method are presented. When the coordinates of all vertices are computed, any feasible point can be expressed as a linear combination of the vertices. The objective function is expressed as a weighted sum of its evaluation at the feasible vertices and the optimal point is associated with the highest/lowest coefficient of the weighted sum. 相似文献
66.
Jung SH 《Lifetime data analysis》1999,5(1):67-79
In a clinical trial with the time to an event as the outcome of interest, we may randomize a number of matched subjects, such as litters, to different treatments. The number of treatments equals the number of subjects per litter, two in the case of twins. In this case, the survival times of matched subjects could be dependent. Although the standard rank tests, such as the logrank and Wilcoxon tests, for independent samples may be used to test the equality of marginal survival distributions, their standard error should be modified to accommodate the possible dependence of survival times between matched subjects. In this paper we propose a method of calculating the standard error of the rank tests for paired two-sample survival data. The method is naturally extended to that for K-sample tests under dependence. 相似文献
67.
为更好地应用DEA评价模型,本文讨论了DEA模型中定性指标的模糊处理及权重分布的随机处理,运用主成分分析法对DEA模型指标体系进行处理,并对DEA评价结果进行了排队分析. 相似文献
68.
在一定条件下,从多目标规划问题的任一可行解的某邻域出发,建立了沿着所建立的常微分方程组的轨线,关于部分交元总收敛到原多目标规划问题的(弱)有效解。 相似文献
69.
70.
基于多目标规划的中国可持续发展模式优化研究 总被引:4,自引:0,他引:4
本文以人口(Population)、资源(Resource)、经济(Economy)、环境(Environment)和科技(Science & Technolo gy)为核心,构造了PREEST系统模型。以PREEST系统为对象,运用主成分分析法对1987-2001年度中国的可持续发展水平进行了综合评价;借助多目标规划理论,构建了中国可持续发展多目标集成模型,并以"十五"计划纲要为基准,开展了中国可持续发展规划研究的实证分析。在此基础上,通过对"十五"期间中国可持续发展传统模式和规划模式的对比分析,就中国人口、资源、经济、环境和科技等领域的协调发展提出了政策建议。 相似文献