“行/列约束法”在外贸进出口货柜运输业务上的应用

外贸日常进出口业务活动中,我们经常遇到如何利用物质资源条件,求取并实现最理想目标的问题。本文研究了货柜运输业务上三维装箱问题,给出了一个基于管理数学中“行约法 /列约法”的摆放方法。通过和外贸进出口业务常规计算方法比较,降低了创汇成本,增加了经济效益。同时和其它方法比较发展,我们的方法在实际货柜装箱操作上,方便实用。     

网络出版研究

网络技术的发展和在出版业中的应用,打破了出版业原有的模式,一种全新的网络出版形成了全球性的、高效率的信息资源共享和传输体系新模式。1998年5月,联合国新闻委员会召开的年会正式宣布,国际互联网被称为继报刊、广播、电视三大传媒之后兴起的"第四媒体",由此,网络出版兴起和发展。当今,以互联网为依托的网络出版正在改变着以纸张为主的传统出版业,推动传统出版业走向网络出版的新时代,网络出版与传统出版、电子出版一起将构筑起新世纪多元化的出版产业。     

邮区中心局选址的一种优选方法

本文利用图论的理论与方法对邮区中心局的选址问题进行优化。首先对其原理做了较详细的描述,然后运用选址算法对邮区中心局的选址进行了优化。     

Semidefinite Programming Relaxations for the Quadratic Assignment Problem

Semidefinite programming (SDP) relaxations for the quadratic assignment problem (QAP) are derived using the dual of the (homogenized) Lagrangian dual of appropriate equivalent representations of QAP. These relaxations result in the interesting, special, case where only the dual problem of the SDP relaxation has strict interior, i.e., the Slater constraint qualification always fails for the primal problem. Although there is no duality gap in theory, this indicates that the relaxation cannot be solved in a numerically stable way. By exploring the geometrical structure of the relaxation, we are able to find projected SDP relaxations. These new relaxations, and their duals, satisfy the Slater constraint qualification, and so can be solved numerically using primal-dual interior-point methods.For one of our models, a preconditioned conjugate gradient method is used for solving the large linear systems which arise when finding the Newton direction. The preconditioner is found by exploiting the special structure of the relaxation. See e.g., Vandenverghe and Boyd (1995) for a similar approach for solving SDP problems arising from control applications.Numerical results are presented which indicate that the described methods yield at least competitive lower bounds.     

Combining Quantitative and Qualitative Measures of Uncertainty in Model-Based Environmental Assessment: The NUSAP System

This article discusses recent experiences with the Numeral Unit Spread Assessment Pedigree (NUSAP) system for multidimensional uncertainty assessment, based on four case studies that vary in complexity. We show that the NUSAP method is applicable not only to relatively simple calculation schemes but also to complex models in a meaningful way and that NUSAP is useful to assess not only parameter uncertainty but also (model) assumptions. A diagnostic diagram can be used to synthesize results of quantitative analysis of parameter sensitivity and qualitative review (pedigree analysis) of parameter strength. It provides an analytic tool to prioritize uncertainties according to quantitative and qualitative insights in the limitations of available knowledge. We show that extension of the pedigree scheme to include societal dimensions of uncertainty, such as problem framing and value-laden assumptions, further promotes reflexivity and collective learning. When used in a deliberative setting, NUSAP pedigree assessment has the potential to foster a deeper social debate and a negotiated management of complex environmental problems.     

碳交易政策下多式联运路径选择问题的鲁棒优化研究

针对碳交易政策下的多式联运路径选择问题,考虑运输时间和单位运费率不确定且其概率分布未知的情况,引入鲁棒优化建模方法对其进行研究。首先利用box不确定集合刻画分布未知的运输时间和运费率,然后在碳交易政策下确定模型的基础上,构建鲁棒性可调节的多式联运路径选择模型,并通过对偶转化得到相对易求解的鲁棒等价模型。实例分析表明,鲁棒模型能较好地处理参数概率分布未知的多式联运路径选择问题,方便决策者根据偏好调整不确定预算水平进行决策。运输时间和单位运费率的不确定性都会影响多式联运路径决策,但是作用机理有所不同。将上述碳交易政策下的模型拓展到其他低碳政策,结果表明多种低碳政策的组合能更好实现多式联运减排。     

资金约束下损失规避零售商的订购和广告协同策略

在损失规避下,探讨了零售商的订购和广告协同决策问题。零售商的初始资金状态存在三种情形：资金充足、资金相对短缺（不需融资）、资金短缺（对外融资）,分别在三种情形下刻画了零售商的最优运营策略,结果表明：零售商用于商品采购和广告的资金产生的边际效用与边际负效用之比相等,且介于1与单位融资资金的使用成本之间;用于两项活动的最后一单位资金产生的边际效用相等。探讨了损失规避、初始资金、融资利率、商品价格及广告促销的敏感性对运营策略的影响：在资金充足或资金短缺下,商品订购量和广告强度随影响因素的变动方向通常相同;在资金相对短缺下,商品订购量和广告强度随影响因素的变动方向则相反。讨论中揭示了一些管理启示。     

一类基于SPE的物流配送量优化模型

在对物流配送过程进行分析时,将完全垄断企业物流配送量优化问题看作一个带“有向边”的网络,从而利用交通网络优化中的用户均衡原则,将物流配送量的优化问题转化为需求函数未知时的空间价格均衡问题。在给出与空间价格均衡问题等价的隐式变分不等式后,利用求解变分不等式的预测-校正方法的思想,对所得的模型进行动态化求解,通过对物流配送量与商品价格的数值观察结果对物流配送量进行动态调整,在经过较少次数的迭代后可以得到最优解。最后给出了数值试验的结果。     

经济批量排产问题的一种排产方法

针对经济批量排产问题假定生产可以在库存降为0之前开始,并且提出新的算法求产品的生产顺序。结果表明,该排产方法成本要低于其他2种常用的经济批量排产问题的方法,并且给出了算法的时间复杂性。     

On the number of local minima for the multidimensional assignment problem

The Multidimensional Assignment Problem (MAP) is an NP-hard combinatorial optimization problem occurring in many applications, such as data association, target tracking, and resource planning. As many solution approaches to this problem rely, at least partly, on local neighborhood search algorithms, the number of local minima affects solution difficulty for these algorithms. This paper investigates the expected number of local minima in randomly generated instances of the MAP. Lower and upper bounds are developed for the expected number of local minima, E[M], in an MAP with iid standard normal coefficients. In a special case of the MAP, a closed-form expression for E[M] is obtained when costs are iid continuous random variables. These results imply that the expected number of local minima is exponential in the number of dimensions of the MAP. Our numerical experiments indicate that larger numbers of local minima have a statistically significant negative effect on the quality of solutions produced by several heuristic algorithms that involve local neighborhood search.Partially supported by the NSF grant DMI-0457473.