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ايجاد التوزيع الاحتمالي للطلب خلال فترة الانتظار للمواد المخزنية في شركة تعبئة الغاز == Finding The Probability Distribution of Lead Time Demand For The Inventory Items In Gas Filling Company
Author name:
علي هشام عبد الرسول السعدي
Supervisor name:
عماد حازم عبودي
General topic:
Administration and Economics
Specific topic:
Statistics
Degree:
Master
University:
University of Baghdad - Faculty Of Administration And Economics - Department Of Statistics
Language:
Arabic
University location:
Baghdad
First pages:
07T3899 - p.pdf
Abstract:
يعد ايجاد التوزيع الاحتمالي للطلب خلال فترة الانتظار من اهم واعقد المشاكل التي تواجه العاملين في مجال السيطرة على الخزين وذلك عندما يكون الطلب او فترة الانتظار او كلاهما متغيرا وبشكل خاص عندما تكون فترة الانتظار طويلة.غالبا ما تستخدم توزيعات ثنائية | Probability distribution for lead time demand is considered the most important and complex problem that is faced by those who work in inventory control when demand or lead time or both of them are not fixed specially when the lead time is long.In common two parameters distributions are used to represent lead time demand, for example Gamma distribution and lognormal distribution. Although these distributions are some what flexible in representing this variable (i.e. lead time demand), it does not cover all cases.Thus, three parameters distributions are used in addition to that two parameters distributions to represent lead time demand. These three parameters distribution are more flexible and take different forms, consequently they are more compatible to cover more cases.This study consists of four chapters; the first one is a historical review and previous studies of some researchers who worked in probabilistic models for inventory control. The second chapter is a theoretical part that discusses some important conceptions which are used in inventory control and display the most important specification and characteristics of some important distributions to represents demand, lead times and lead time demand, that is the later is the most important to compute different inventory measures, which is limited on re - order level and protection level in this thesis. In addition it shows estimation of distributions parameters by using moment method and Maximum likelihood.The third chapter is the experimental part which tackles the analysis of actual monthly data and lead times data measured by month to find best probability distribution to these data. Then, mix demand data with lead time data. Thus, we get demand data during lead time. These data are tested to get probability distribution which represents them. This distribution depends on computing re - order level in specific protection levels.The forth chapter discusses the most important conclusions of this thesis and recommendations are suggested to the future studies.Further to that, the thesis contains a programs in Pascal language to get use of it to generate lead time demand data, and to test goodness of fit of data and computing re - order level according to lead time demand distributions.
