Control Mechanisms in Queueing Systems with Nonlinear Waiting Costs
In many queueing systems, customers have been observed to exhibit strategic behavior. Each customer gains a value when receiving a product or getting served and suffers when incurring a delay. We consider a nonlinear waiting cost function to capture the sensitivity of customers toward delay. We investigate customers' behavior and system manager's strategy in two different settings: (1) customers are served in a service system, or (2) they receive a product in a supply chain. In the first model, we study an unobservable queueing system. We consider that customers are impatient, and are faced with decision problems whether to join a service system upon arrival, and whether to remain or renege at a later time. The goal is to address two important elements of queueing analysis and control: (1) customer characteristics and behavior, and (2) queueing control. The literature on customer strategic behavior in queues predominately focuses on the effects of waiting time and largely ignores the mixed risk attitude of customer behavior. Empirical studies have found that customers’ risk attitudes, their anticipated time, and their wait time affect their decision to join or abandon a queue. To explore this relationship, we analyze the mixed risk attitude together with a non-linear waiting cost function that includes the degree of risk aversion. Considering this behavior, we analyze individuals' joint balking and reneging strategy and characterize socially optimal strategy. To determine the optimal queue control policy from a revenue-maximizer perspective, which induces socially optimal behavior and eliminates customer externalities, we propose a joint entrance-fee/abandonment-threshold mechanism. We show that using a pricing policy without abandonment threshold is not sufficient to induce socially optimal behavior and in many cases results in a profit lower than the maximum social welfare the system can generate. Also, considering both customer characteristics and queue control policy, our findings suggest that customers with a moderate anticipation time provide higher expected revenue, acknowledging the importance of understanding customer behavior with respect to both wait time and risk attitude in the presence of anticipation time. In the second model, we consider a two-echelon production inventory system with a single manufacturer and a single distribution center (DC) where the manufacturer has a finite production capacity. There is a positive transportation time between the manufacturer and the DC. Each customer gains a value when receiving the product and suffers a waiting cost when incurring a delay. We assume that customers' waiting cost depends on their degree of impatience with respect to delay (delay sensitivity). We consider a nonlinear waiting cost function to show the degree of risk aversion (impatience intensity) of customers. We assume that customers follow the strategy p where they join the system and place an order with probability p. We analyze the inventory system with a base-stock policy in both the DC and the manufacturer. Since customers and supply chain holder are strategic, we study the Stackelberg equilibrium assuming that the DC acts as a Stackelberg leader and customers are the followers. We first obtain the total expected revenue and then derive the optimal base-stock level as well as the optimal price at the DC.