两厂商情形下二度价格歧视的需求分段数研究

在线性需求函数条件下,对两寡头厂商实行二度价格歧视进行了静态博弈分析,以确定对需求量区间的合理分段数.研究结果表明:对需求量区间的划分原则和评价标准以及分段数目类似于垄断情形,仍以二至三段为宜.     

A SIMPLE ITERATIVE PROCEDURE FOR FINDING ALL ZEROS OF A POLYNOMIAL WITHOUT REPEATED EVALUATION

In this note a simple iterative method for simultaneously finding all zeros of a polynomial is established.The method does not require repeated evaluation of the polynomial or its deriva-tives,and is globally convergent for quadratic polynomials.     

照相法研究抛射体运动

介绍了利用多次曝光法研究了小球的抛射体运动，设计了实验装置，通过用表差法处理实验数据，从而探索抛射体的运动规律并求得重力加速度值，通过对实验的误差分析，给出了结果的不确定度评定。     

含成本因素的出口退税的博弈模型研究

利用博弈论的分析方法进一步考虑成本因素 ,在更为一般的条件下分别建立了税务机关与外贸企业之间的完全信息静态博弈模型和无限阶段重复博弈模型 .得到国家税务机关最优混合策略及其骗税罚款系数公式 ,并且讨论了多种因素对局中人的影响 ,提出了降低企业骗税概率的建议 .     

An Inventory System with Postponed Demands

Abstract

In this article we consider a continuous review perishable inventory system in which the demands arrive according to a Markovian arrival process (MAP). The items in the inventory have shelf life times that are assumed to follow an exponential distribution. The inventory is replenished according to an (s, S) policy and the replenishing times are assumed to follow a phase type distribution. The demands that occur during stock out periods either enter a pool which has capacity N (<∞) or leave the system. Any demand that arrives when the pool is full and the inventory level is zero, is also assumed to be lost. The demands in the pool are selected one by one, if the replenished stock is above s, with interval time between any two successive selections is distributed as exponential with parameter depending on the number of customers in the pool. The joint probability distribution of the number of customers in the pool and the inventory level is obtained in the steady state case. The measures of system performance in the steady state are derived and the total expected cost rate is also calculated. The results are illustrated numerically.     

COMBINING SOCIAL CAPITAL AND TECHNOLOGY FOR DROUGHT RESILIENCE IN AGRICULTURE

In water‐scarce regions of the world, water‐saving technology adoption augments farm productivity. But so does social capital. In this paper, the issue of ensuring livelihood for farmers through the combined use of social capital and water‐saving technology is modeled in the context of repeated droughts. The model presented here derives optimal resource conservation and accumulation strategies when the farmer must ensure minimum consumption during a set of repeated drought events in the future. Findings indicate that the path to drought resilience presents a complex trade‐off between accumulating one form of capital over another and is influenced by farmers’ wealth and water endowments, level of risk associated with the repeated droughts and the duration of the repeated drought event that the farmer plans to survive. A higher risk of repeated droughts leads to an increase in groundwater conservation efforts but delays technology adoption. Lower water endowments may also delay adoption and reduce social capital, however, a lower social capital or a slow rate of its growth is not a hindrance to adopting water‐saving technology earlier. Finally, social capital evolves to higher levels when farmer is simultaneously faced with a higher level of risks and a longer span of drought events.     

基于动态遗传算法的共享配送模式研究

针对传统配送中配送车辆装载率低、车辆数量多及配送成本高等问题,提出不同类型零售商资源共享的城市配送优化方法,并考虑配送中的车辆油耗与不确定需求等问题。以总配送成本最低为目标建立模型,利用基于动态参数的改进遗传算法对模型进行求解。最后,通过算例对共享配送模式与算法进行测试。结果表明,共享配送模式能够有效减低车辆数量、提高装载率及降低配送成本,同时改进遗传算法能够高效、准确对模型求解。     

连续激光重复加载下30CrMnSiA钢的反射率

利用双光束反射率测量装置,研究了连续激光重复加载作用下30CrMnSiA钢金属材料的反射率变化特性。通过激光加载、冷却然后再加载到更高的温度的辐照试验与激光单次辐照的结果比较,发现二次加载时材料表面的激光反射率与样品表面首次加载时达到的最高温度所对应的反射率基本一致,只有达到并超过首次加载时样品曾达到的最高温度后,样品表面的反射率才会再次发生变化,且变化趋势与单次完整加载时的路径重合。这表明样品表面的反射率与其达到的最高温度有关,进一步的研究结果表明,样品达到的最高温度与样品表面在最高温度下产生的氧化反应层有关,而这一氧化层在冷却过程和再加载过程不变化。