Increasing profitability with inventory management and vehicle routing problem with simultaneous pickup and delivery during the pandemic period: Application in a defense industry company

Intense competition, technological developments, and capital mobility in the world have affected the survival of businesses and the need to use their resources as effectively and efficiently as possible has emerged. In particular, the COVID-19 pandemic has initiated a wave of economic downturn worldwide due to disruptions in the supply and demand chain for the supply market. The first part of this study, it is trying to determine whether there is any relationship between the management of inventories and the profitability of an enterprise operating in the defense industry between 2019-2022 through financial ratios. When the statistical results obtained using the IBM SPSS program are examined, statistically significant relationships between inventory management and profitability are observed. In the second part of the study, improvement studies were carried out to ensure that the number of stocks waiting to be delivered to the next station as semi-finished products in the company decreased rapidly. In doing so, the simultaneous pick-and-delivery vehicle routing problem was analyzed and the heuristic method developed from the model was used. The simultaneous pickand-deliver vehicle routing problem is a vehicle routing problem in which the distribution and collection demands of customers are met simultaneously. It is aimed to create vehicle routes that will move the maximum number of work orders between stations and minimize the distance traveled. A heuristic algorithm was developed to solve the problem and a new solution was proposed by using a Python program. The current data obtained has started to be used in the buildings determined in the production facilities of the company. Keywords: Inventory Management, Profitability, Pandemic, Vehicle Routing, Pickup and Delivery Time Windows, Heuristic Algorithm