Pengembangan Model Persediaan Bahan Baku Multi Item dengan Mempertimbangkan Kadaluwarsa, Unit Diskon pada Permasalahan Non-Konstan Demand

In the classical economic ordering quantity (EOQ) model, it was assumed that products have no expire date. However, in practices, some products such as food and milk, have exact expire date and some vendors tries to reduce their lost by introducing quantity unit discount. In this paper, we develop multi items inventory models by considering product expire date and quantity unit discount for stochastic demand environment. Due to complexity of the models, simulation and Genetic Algorithm are used to solve the models. We then verify the models using a numerical example and sensitivity analysis. The results from sensitivity analysis show that inventory cost and backorder cost have significant effect to ordering time.