随机库存问题.docVIP

随机库存模型 上机问题2 某企业对于某种材料的月需求量为随机变量，具有如下表概率分布： 需求量 （吨） 50 60 70 80 90 100 110 120 0.10 0.20 0.15 0.25 0.05 0.10 0.10 0.05 每次订货费为500元，每月每吨保管费为50元，每月每吨货物缺货费为1500元，每吨材料的购价为1000元。该企业欲采用周期性盘点的策略来控制库存量，求最佳的，值。 （注：策略指的是若发现存货量少于s时立即订货，将存货补充到S，使得经济效益最佳。） 解答：可以用如下方式建立模型，对于每个S和s取若干个月模拟，每个月需求量随机产生，将这些月所有花费，订货费，保管费，缺货费和购货费全部加起来，然后比较每个S和s所得的数字，取出最小花费，在此我取了6000个月进行模拟，在文件夹中付原程序文件 由S从80到129，s从50到S，意思是s取到所有比S小但大于50的数，由于计算机性能有限，只能取到这些数，S和s的所有取值如下，{s,S} {{50,80},{51,80},{52,80},{53,80},{54,80},{55,80},{56,80},{57,80},{58,80},{59,80},{60,80},{61,80},{62,80},{63,80},{64,80},{65,80},{66,80},{67,80},{68,80},{69,80},{70,80},{71,80},{72,80},{73,80},{74,80},{75,80},{76,80},{77,80},{78,80},{79,80},{80,80},{50,81},{51,81},{52,81},{53,81},{54,81},{55,81},{56,81},{57,81},{58,81},{59,81},{60,81},{61,81},{62,81},{63,81},{64,81},{65,81},{66,81},{67,81},{68,81},{69,81},{70,81},{71,81},{72,81},{73,81},{74,81},{75,81},{76,81},{77,81},{78,81},{79,81},{80,81},{81,81},{50,82},{51,82},{52,82},{53,82},{54,82},{55,82},{56,82},{57,82},{58,82},{59,82},{60,82},{61,82},{62,82},{63,82},{64,82},{65,82},{66,82},{67,82},{68,82},{69,82},{70,82},{71,82},{72,82},{73,82},{74,82},{75,82},{76,82},{77,82},{78,82},{79,82},{80,82},{81,82},{82,82},{50,83},{51,83},{52,83},{53,83},{54,83},{55,83},{56,83},{57,83},{58,83},{59,83},{60,83},{61,83},{62,83},{63,83},{64,83},{65,83},{66,83},{67,83},{68,83},{69,83},{70,83},{71,83},{72,83},{73,83},{74,83},{75,83},{76,83},{77,83},{78,83},{79,83},{80,83},{81,83},{82,83},{83,83},{50,84},{51,84},{52,84},{53,84},{54,84},{55,84},{56,84},{57,84},{58,84},{59,84},{60,84},{61,84},{62,84},{63,84},{64,84},{65,84},{66,84},{67,84},{68,84},{69,84},{70,84},{71,84},{72,84},{73,84},{74,84},{75,84},{76,84},{77,84},{78,84},{79,84},{80,84},{81,84},{82,84},{83,84},{84,84},{50,85},{51,85},{52,85},{53,85},{54,85},{55,85},{56,85},{57,85},{58,85},{59,85},{60,85},{61,85},{62,85},{63,85},{64,85},{65,85},{66,85},{67,85},{68,85},{69,85},{70,85},{71,85},{72,85},{73,85},{74,85},{75,85},{76,85},{77,85},{78,85