Supplier‐buyer contracting: Asymmetric cost information and cutoff level policy for buyer participation

We consider the problem of designing a contract to maximize the supplier's profit in a one‐supplier–one‐buyer relationship for a short‐life‐cycle product. Demand for the finished product is stochastic and price‐sensitive, and only its probability distribution is known when the supply contract is written. When the supplier has complete information on the marginal cost of the buyer, we show that several simple contracts can induce the buyer to choose order quantity that attains the single firm profit maximizing solution, resulting in the maximum possible profit for the supplier. When the marginal cost of the buyer is private information, we show that it is no longer possible to achieve the single firm solution. In this case, the optimal order quantity is always smaller while the optimal sale price of the finished product is higher than the single firm solution. The supplier's profit is lowered while that of the buyer is improved. Moreover, a buyer who has a lower marginal cost will extract more profit from the supplier. Under the optimal contract, the supplier employs a cutoff level policy on the buyer's marginal cost to determine whether the buyer should be induced to sign the contract. We characterize the optimal cutoff level and show how it depends on the parameters of the problem. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 41–64, 2001     

Markovian approximation for manufacturing systems of unreliable machines in tandem

This paper studies production planning of manufacturing systems of unreliable machines in tandem. The manufacturing system considered here produces one type of product. The demand is assumed to be a Poisson process and the processing time for one unit of product in each machine is exponentially distributed. A broken machine is subject to a sequence of repairing processes. The up time and the repairing time in each phase are assumed to be exponentially distributed. We study the manufacturing system by considering each machine as an individual system with stochastic supply and demand. The Markov Modulated Poisson Process (MMPP) is applied to model the process of supply. Numerical examples are given to demonstrate the accuracy of the proposed method. We employ (s, S) policy as production control. Fast algorithms are presented to solve the average running costs of the machine system for a given (s, S) policy and hence the approximated optimal (s, S) policy. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 65–78, 2001     

菜籽油制备生物柴油及其理化性能的研究

研究了植物油(菜籽油)在NaOH催化作用下与甲醇反应制备生物柴油的工艺条件,考察了醇油摩尔比、催化剂用量、反应时间和反应温度等条件对反应的影响,实验结果表明该反应较适宜的条件为:反应温度50℃、醇油摩尔比6:1、催化剂用量为原料油质量的0.8％、反应时间为20min。对所得生物柴油的主要性能指标进行了考察,发现除粘度较大外,其主要性能指标与我国O#柴油相接近,掺入少量柴油后完全可以作为柴油机燃料使用。     

新疆区内初中班化学教学中的难点及对策研究

九年级化学作为起始学科，在进行教学时存在许多困难，而“内初班”学生的学情与本地学生不同，教学难度更大，存在师生交流不畅、学生的理解偏差、生活习惯差异以及缺乏课外教学素材等问题。因此，需在深入了解学情和以上问题的基础上，逐一攻破知识较为抽象、语言理解困难、生活经验有差异等教学难点，通过建立深厚的师生感情、提高学生学习化学的信心、加强化学用语的练习、强调易错、易混淆知识点等方式，达到切实提高学生化学学习能力的目的。     

敷设气囊的充水圆柱壳的声辐射

为降低充水圆柱壳受内部点声源激励时的水下辐射噪声，在其外壳上敷设气囊，形成气囊圆柱壳。为指导气囊圆柱壳的设计，将充水裸圆柱壳和充水气囊圆柱壳分别简化为单、双层无限长隔板。比较隔板、气体与水的波阻抗，分析了气体声速与层厚对双层无限长隔板在平面声波入射时低频声辐射的影响机理。分析表明，声速小的气体和适当的气层厚度可以降低双层障板的辐射噪声。采用声无限元法计算了气囊圆柱壳的水下声辐射，结论与对隔板的机理分析吻合。优化设计出的充水CO2气囊圆柱壳的水下辐射声功率与远场辐射声压明显低于充水裸圆柱壳。     

软件可靠性分配的遗传模型研究

对软件可靠性分配的遗传模型进行了研究,结合相关知识缩小了基本遗传算法的搜索区域,比较灵活地处理了非线性约束条件,提高了搜索效率,避免了早熟收敛现象.此外,在基本遗传算法中增加了保优操作,从而能够在理论上保证实现分配的最优化.算例表明,该算法十分有效.     

Inventory transshipment game with limited supply: Trap or treat

Inventory transshipment is generally shown to be beneficial to retailers by matching their excess demand with surplus inventory. We investigate an inventory transshipment game with two newsvendor-type retailers under limited total supply and check whether the retailers are better off than the case without transshipment. We derive the ordering strategies for the retailers and show that unlike the unlimited supply case, a pure Nash equilibrium only exists under certain conditions. Furthermore, contrary to the conventional wisdom, we show that inventory transshipment may not always benefit both retailers. Although one of the retailers is guaranteed to be better off, the other could be worse off. The decision criteria are then provided for the retailers to determine if they will benefit from the exercise of inventory transshipment. Numerical study indicates that the carefully chosen transshipment prices play an important role in keeping inventory transshipment beneficial to both retailers. Subsequently, a coordinating mechanism is designed for the retailers to negotiate transshipment prices that maximize the total profit of the two retailers while keeping each of them in a beneficial position.     

谈CAI在化学教学中的作用

本文从CAI在化学教学中可以提高教学水平和质量,培养学生自学和创新思维的能力,提高教师的业务素质三方面进行了探讨,分析了CAI在化学教学中的作用。     

中低速磁浮列车传感器防浪涌设计及改进

为提高磁浮列车悬浮传感器的可靠性,分析在雷击、电源干扰等工况条件下的浪涌产生机理,确定浪涌冲击试验的内容,从通流量的角度说明已有防浪涌电路设计的可行性,并指出其在高温环境下在可靠性方面存在的不足。分别从降压和分流的角度进行分析,通过在原有电路中并接大容量电容的方式降低浪涌对敏感器件的冲击,从而提高传感器电源的抗浪涌冲击能力。