VAR SAK PÅ SIN PLATS : En blandning av Tilldelnings- och Kappsäcksproblemet anpassat för optimering av Cytivas lagerstruktur

Sammanfattning: Cytiva is a pharmaceutical company in Umeå that manufactures and administer hardware for medical instruments. A recurring problem for Cytiva is a lack of storage space, which is why they currently rent an external warehouse. The lack of space often results in the need to change storage places for items in order to create more storage space. Currently, these changes are made without really knowing the overall effect they have on the system. Moving items around in a warehouse is a common problem type for optimization. There are several proven analysis and optimization methods to combat this problem and many of these solution methods optimize warehouses with one point for input and output (I/O). There are significantly fewer methods that optimize warehouses built using a supermarket structure, i.e. with several I/O. Since Cytiva has a supermarket structure the purpose of this work is thus to create a model to apply optimization methods, where the model evaluates and optimizes the relocation of items within a warehouse built in a supermarket structure. With inspiration from the Assignment Problem and the Knapsack Problem, a mathematical model is formulated for the analysis and optimization of Cytiva’s inventory. The model relocates items between different supermarkets instead of between specific storage locations. Because of the size of the problem, a greedy algorithm is used to solve the optimization. Results are generated and then used to provide suggestions for the optimal stocking of items and to analyze three specific scenarios. The model provides a picture of how the flow will be affected by the three specific scenarios and makes corresponding recommendations thereafter. Concerning Cytiva’sinventory currently, it is concluded that there are indications that Cytiva’s flow can be improved by reviewing inventory. However, further research and development are needed to provide a reliable relocation proposal