From master's program to Ph.D., interdisciplinary environment keeps graduate student in Minnesota

Yishun Luo applies queueing theory to the cloud

MINNEAPOLIS / ST. PAUL (04/03/2026) — Data center servers receive multitudes of jobs per second. If not managed well, this high volume of information can impact a company's bottom line—and affect the user who is streaming, downloading or uploading images, or playing video games.

Yishun Luo, a second-year doctoral student in the University of Minnesota College of Science and Engineering, is researching how to better assign jobs to these servers.

“One of the challenges is to decide which server handles what job,” Luo said. 

In simulations, he found that shortest-queue routing loses much of its advantage when queue lengths can’t be observed continuously. He’s developing a low-overhead rule that samples periodically and avoids the longest queues, keeping delays near-optimal even under heavy traffic.

“Our University creates a very supportive, interdisciplinary environment for us to conduct research,” said Luo, who started in the Department of Industrial and Systems Engineering (ISyE) master’s program. He decided to further his studies at the University of Minnesota because of his faculty advisors—Martín Zubeldía, an expert in applied probability in ISyE, and Hailong Cui, a Carlson School professor who studies supply chain sustainability.

In the video below, Luo shares his research and reasons to choose Minnesota.

Read about Luo and Zubeldía work in "Growth and Efficiency in the Cloud" on the ISyE website.

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