Analisis Pengendalian Persediaan Dua Jenjang dengan Kebutuhan Berdistribusi Normal dan Waktu Tenggang Tetap dengan Menggunakan Kebijakan N-Siklus-Tunggal

Abstract

Inventory problems cover a wide scope, which can be found not only in manufacturing systems but also in non-manufacturing systems. Basically, inventory problems arise from events where there is too much inventory or too little inventory to meet consumer demand, which ultimately results in losses. Considering the large role of inventory, experts have developed various inventory models. Parapat Gultom (1989) in his thesis developed an inventory model for a two-tier distribution system by assuming that demand is normally distributed but lead times are fixed, and delivery times can be made immediately. The assumptions put forward by the author are basically not always acceptable. Sometimes there is a need to follow a certain distribution pattern and there is a delivery/manufacturing lead time. Therefore, in this paper, an inventory model is developed for a two-level distribution system with normally distributed requirements and fixed lead times. In developing the model in this paper it was developed using the N-Single-Cycle policy. The aim to be achieved in developing this model is to determine the optimal inventory level for all levels so that the total costs for all minimum levels with different parameters are then reviewed from several of these parameters which have the biggest influence to get the total costs for all minimum levels by applying them to various cases. From experimenting with the following parameters, it was obtained that the best case example which gives a minimum total average cost per year is the case where storage costs at the Central Warehouse increased by 10% with total costs decreasing by 9%.