Integrated Lot Sizing In Supply Chain With Time-varying Delivery Cycle

An integrated lot-sizing problem with time-varying delivery cycle is common in practice. In order to provide the support for the supply chain decision, two supply chains which are powerfully impacted by time-varying delivery cycle are studied in this paper. The integrated lot-sizing problems are solved in the two supply chains, based on the analysis of the system characters and the influence mechanisms respectively.Regression analysis method is used to describe and model the time-varying delivery cycle based on large practical data and three delivery cycle tendencies are concluded: scattered, linear tendency and non-linear tendency. Two ways of time-varying delivery cycle impact on integrated lot-sizing decisions are concluded based on the analysis of the system characters.One way is that time-varying in-transit inventory cost during delivery process can change the system parameters. A general method which is used in dynamic lot-sizing problem is adopted to solve the integrated lot-sizing problem with time-varying in-transit inventory cost in a supply chain with a general periodically customer ordering policy. A new discrete searching method is established to solve the same problem in a supply chain with a JIT customer ordering policy.Anther way is that time-varying delivery can change production capacity. Different changes under different time-varying delivery cycle are studied and conclude that, only under linear tendency delivery cycle situation, the problem probably becomes to an integrated lot-sizing decision with constant capacitated constraints which can be solved by polynomial method. A new mixed push and pull searching method is established to solve the new integrated lot-sizing decision problem with constant capacitated constraints in the middle of the supply chain system.At last a new lot-sizing decision support system under time-varying delivery cycle is established by using visual Basic and Matlab.