Abolfazl Kazemi - Faculty of Industrial and Mechanical Engineering, Qazvin Branch, Islamic Azad University, Qazvin, Iran
Danial Esmaeili Aliabadi - Faculty of engineering and natural science, Sabanci university, Istanbul, Turkey

There are many benefits for coordination of multiple suppliers when single supplier cannot satisfy buyer demands. In addition, buyer needsto purchase multiple items in a real supply chain. So, a model that satisfies these requests has many advantages. We extend the existingapproaches in the literature that assume all suppliers need to be put on a common replenishment cycle and each supplier delivers exactlyonce in a cycle. More specifically, inspired by approaches that perform well for the Economic Lot Scheduling Problem, we assume aninteger number of times a supplier can ship available items in an overall replenishment cycle. Because of complexity issue, a new approachbased on genetic algorithm is employed to solve the presented model. Results depict that new model is more beneficial and practical.

Integrated supply chain, Multi-item, Frequent shipping, Multi-supplier, Supplier selection