tailieunhanh - CONCEPTS FOR SAFETY STOCK DETERMINATION UNDER STOCHASTIC DEMAND AND DIFFERENT TYPES OF RANDOM PRODUCTION YIELD

In a series of preliminary tests, we examined the pattern of mean daily returns throughout the lunar month, including visual inspections of return histograms. This examination reveals one interesting regularity. We observe that high returns tend to cluster around the new moon date, while low returns tend to cluster around the full moon date. Following this observation, we structure our returns tests to reflect the possible difference between new moon and full moon periods. Specifically, most of our tests are simple comparisons of mean daily returns for various return windows centered on the new moon and. | WORKING PAPER SERIES Concepts for Safety Stock Determination under Stochastic Demand and Different Types of Random Production Yield Karl Inderfurth Stephanie Vogelgesang Working Paper No. 03 2011 OTTO VON GUERICKE UNIVERSITÃT MAGDEBURG FACULTY OF ECONOMICS AND MANAGEMENT Impressum 5 TMG Herausgeber Otto-von-Guericke-Universitat Magdeburg Fakultat fur Wirtschaftswissenschaft Der Dekan Verantwortlich fur diese Ausgabe Karl Inderfurth Otto-von-Guericke-Universitat Magdeburg Fakultat fur Wirtschaftswissenschaft Postfach 4120 39016 Magdeburg Germany http femm Bezug uber den Herausgeber ISSN 1615-4274 Concepts for Safety Stock Determination under Stochastic Demand and Different Types of Random Production Yield Karl Inderfurth and Stephanie Vogelgesang Faculty of Economics and Management Otto-von-Guericke University Magdeburg POB 4120 39106 Magdeburg Germany Phone 49 391 6718819 Fax 49 391 6711168 Abstract We consider a manufacturer s stochastic production inventory problem under periodic review and present methods for safety stock determination to cope with uncertainties that are caused by stochastic demand and different types of yield randomness. Following well-proven inventory control concepts for this problem type we focus on a critical stock policy with a linear order release rule. A central parameter of this type of policy is given by the safety stock value. When non-zero manufacturing lead times are taken into account in the random yield context it turns out that safety stocks have to be determined that vary from period to period. We present a simple approach for calculating these dynamic safety stocks for different yield models. Additionally we suggest approaches for determining appropriate static safety stocks that are easier to apply in practice. In a simulation study we investigate the performance of the proposed safety stock variants. Keywords stochastic demand random yield yield models .