Lehigh ISE Professor Ted Ralphs has been elected Chair-Elect of the Bilevel Optimization Society (BOS). He will serve a one-year term as Chair-Elect before assuming a two-year term as Chair, followed by one year as Past Chair. Bilevel optimization is a field of optimization that addresses hierarchical optimization problems in which a leader (upper level) decides the values of a set of decision variables and a follower (lower level) reacts by solving a problem that depends on the leader’s choice. The leader’s decision must account for the follower’s reaction and this is what makes these problems challenging. Prof. Ralphs’ work on branch-and-cut and decomposition algorithms, as well as advanced mixed-integer programming formulations for solving bilevel problems, has made him a world expert on the subject.
The BOS is a technical section of the Mathematical Optimization Society (MOS). The goal of the BOS is to create and maintain a community of researchers that recognize their work as related to bilevel optimization, while at the same time expanding its basis and promoting its outreach within and outside academia. One key vehicle for achieving this goal is the International Conference on Bilevel Optimization (ICBO) series. The 2026 ICBO will occur in Pennsylvania in August, hosted jointly by the University of Pittsburgh and Carnegie Mellon University.
Dr. Ralphs’ research focuses primarily on large-scale computation and optimization. His work spans theory, computation, and applications, with the goal of bridging the gap between theory and practice. He is a Fellow of INFORMS and serves as an area editor for Operations Research, as well as a technical editor for Mathematical Programming C. He has developed and maintained variety of software packages, benchmark libraries, and open-source repositories, including influential platforms such as MIPLIB and COIN-OR, making deep and lasting contributions to the operations research and optimization communities.
In his own words, leading the ICBO will be “a fantastic opportunity to contribute to the early development of an organization whose mission I strongly believe in and that I was involved in founding. It is indeed an honor to be chosen for this role by my colleagues around the world.”
