The Impact of Time and Time Delay on the Bullwhip Effect in Supply Chains

Modeling and measuring the demand variance propagation from the initial hours of the supply chain (SC) to the final hours is one of the most important challenges facing the logestics experts. Factors such as time delay increase demand fluctuations over the time in SC networks. This problem often referred to the Bullwhip Effect (BWE) in production systems. In this paper, a flight scheduling network as a supply chain are designed using Inverse Data Envelopment Analysis (IDEA). The effects of the arrival time of the aircraft (landing time) to the airport, as well as the delayed flights (depart time with delay) to the next destination on the demand variance were examined. The results show that demand fluctuations increased significantly by delaying flights in the closing hours. Also, the bullwhip effect due to landing time, at the beginning of the day are more than the final flight hours. This means that due to the higher demand during office hours (beginning of the day), there are many fluctuations in the variance of orders. Comparing the results with the control engineering approach, we found that the proposed method shows the hidden points (effect of flight shifts on involuntary oscillations) of the size of the bullwhip effect. While these hidden points have not been identified in previous methods.