This paper considers a closed queueing network model of ridesharing systems, such as Didi
Chuxing, Lyft, and Uber. We focus on empty-car routing, a mechanism by which we control …

In this paper, we survey results for the GI/GI/N+ GI queueing model. Our focus is on finding
situations in which simple performance measure approximations can be developed. To do …

Diffusion approximations have been a popular tool for performance analysis in queueing
theory, with the main reason being tractability and computational efficiency. This dissertation …

This paper provides an introduction to the Stein method framework in the context of steady-
state diffusion approximations. The framework consists of three components: the Poisson …

The performance of a call center is sensitive to customer abandonment. In this survey paper,
we focus on G/GI/n+ GI parallel-server queues that serve as a building block to model call …

Motivated by queues with many servers, we study Brownian steady-state approximations for
continuous time Markov chains (CTMCs). Our approximations are based on diffusion models …

We describe a fluid model with time-varying input that approximates a multiclass many-
server queue with impatient customers and time-varying arrivals (specifically, the multiclass …

We consider a class of queueing systems that consist of server pools in parallel and multiple
customer classes. Customer service times are assumed to be exponentially distributed. We …

Abstract Extending Ward Whitt's pioneering work “Fluid Models for Multiserver Queues with
Abandonments, Operations Research, 54 (1) 37–54, 2006,” this paper establishes a many …

We study G/G/n+ GI queues in which customer patience times are independent, identically
distributed following a general distribution. When a customer's waiting time in queue …