A hybrid inventory management system responding to regular demand and surge demand

This paper proposes a hybrid policy for a stochastic inventory system facing regular demand and surge demand. The combination of two different demand patterns can be observed in many areas, such as healthcare inventory and humanitarian supply chain management. The surge demand has a lower arrival rate but higher demand volume per arrival. The solution approach proposed in this paper incorporates the level crossing method and mixed integer programming technique to optimize the hybrid inventory policy with both regular orders and emergency orders. The level crossing method is applied to obtain the equilibrium distributions of inventory levels under a given policy. The model is further transformed into a mixed integer program to identify an optimal hybrid policy. A sensitivity analysis is conducted to investigate the impact of parameters on the optimal inventory policy and minimum cost. Numerical results clearly show the benefit of using the proposed hybrid inventory model. The model and solution approach could help healthcare providers or humanitarian logistics providers in managing their emergency supplies in responding to surge demands.     

基于整数规划强对偶求解一类局域性资源受限项目调度问题

资源受限项目调度问题(简称RCPSP)是最具代表性的项目调度问题之一,调度过程可理解为,将受资源约束的平行工序调整为顺序工序。本文针对实际中广泛存在的资源局域、而非全局受限的情况,研究局域性RCPSP,并重点考虑一类问题：项目某环节的一系列平行工序,可用资源量只有一半,各资源可重复利用且具有相应多功能,但最多能承担2个工序,需将这些工序两两排列成对,实现项目工期最短。本文首先探索问题“局域性”特征,量化局域调度对项目工期的影响;基于此,构建只涵盖“局域调度工序”的0-1规划模型;再者,发展整数规划强对偶理论,结合Dangzig-Wolfe分解等方法,提出多项式时间的精确算法;最后通过算例测试,验证算法优势,例如,计算大规模算例的最优解,运用该算法比常规精确方法可快数万倍以上。     

超视距空战中的多无人机武器目标分配方法

武器目标分配问题是多无人机超视距空战中的关键决策问题之一。本文考虑超视距空战的强对抗、不确定等特点给武器目标分配问题带来的新挑战，基于纳什均衡博弈思想，将超视距空战中的多无人机武器目标分配问题建模为双矩阵博弈模型，其中，基于证据理论设计多级信息融合方法计算多个无人机对抗多个目标时的总攻击有效性。在此基础上，基于纳什均衡中策略被选择的概率与遗憾值之间的关系以及超视距空战需求，将双矩阵博弈模型转换为混合整数规划模型进行求解，并通过典型案例、数值实验、仿真实验对本文方法的计算过程和有效性进行分析。结果表明，本文方法能够有效给出超视距空战中的多无人机武器目标分配方案。     

无人仓系统储位分配问题的优化模型与算法

考虑到无人仓系统补货阶段货架上只有部分空余储位的特点，研究了补货商品储位分配问题的优化模型与算法。以同一货架上存放的商品之间关联度之和最大化为目标建立了混合整数规划模型；结合贪婪算法和邻域搜索算法设计了求解模型的两阶段方法。第一阶段利用贪婪算法求初始可行解；第二阶段利用邻域搜索算法对初始可行解进行优化。利用一个具体算例验证了邻域搜索算法的优化效果，结果显示，通过邻域搜索算法对初始可行解的优化，可以使目标函数值至少提升27%。进一步利用多个小规模算例分析了两阶段算法的近似比和求解速度，验证了算法的快速有效性。本文的研究结果不仅解决了货架初始状态非空情况下的储位分配问题，同样适合解决货架初始状态为空的情况，因此更加符合实际场景，可以作为无人仓管理信息系统的核心模型和算法。     

基于收益管理的邮轮客舱分配与定价模型

基于收益管理的思想对邮轮客舱分配与定价问题进行了研究。结合邮轮运营中的个性化特点，例如消费者团体人员构成多样、较长的预售周期以及救生位和儿童看护人员的数量限制等。在不失一般性的前提下，建立了整数规划模型用以确定在预售周期内的不同预售阶段中各种客舱类型的待售数量及其价格，以达到使邮轮公司收益最大化的目的。实验分析表明，该模型在实际应用中是有效的且呈现出显著的年增长趋势，可明显提高邮轮公司的收益。此外，设计了一种基于韦伯分布的EM算法用以解决模型中涉及到的需求量的无约束估计问题。数值算例研究表明，该算法收敛速度快且无约束估计过程可靠有效。     

Accuracy of Numerical Solutions Using the Euler Equation Residuals

This paper is concerned with asymptotic properties on the accuracy of numerical solutions. It is shown that the approximation error of the policy function is of the same order of magnitude as the size of the Euler equation residuals. Moreover, for bounding this approximation error the most relevant parameters are the discount factor and the curvature of the return function. These findings provide theoretical foundations for the construction of tests to assess the performance of alternative computational methods.     

The Design of Feature‐Limited Demonstration Software: Choosing the Right Features to Include

Today, software supports many important tasks in a variety of industries. In the specialized nature of these environments, a common problem faced by software vendors is to correctly signal the true value of a software product to the end users. For example, telecommunications equipment manufacturers design complex software for important functions like provisioning new users in the network. These software products automate various functions that would otherwise need to be done manually. In order to enable potential customers—telecommunications providers—to evaluate and recognize the full value of the product, equipment vendors often provide a free, feature‐limited version of the product to the customer. As the specific features included in the feature‐limited version influence whether the full product is purchased or not, it is essential that the features included in the feature‐limited version be selected judiciously. While the importance of identifying the best set of features has been well recognized, there has been little research to date that systematically addresses this fundamental business decision. This study fills this gap in the literature by providing an objective approach to the design of demonstration software. We illustrate the benefits of our approach through a case study involving the design of a feature‐limited demo for a wireless telecommunications equipment manufacturer.