Publications

Lifting cover inequalities for the robust knapsack problem

Published in Operations Research Letters, 2025

We propose a novel lifting method that leverages upper bounds for lifting problems. First, we introduce a strong, efficiently computable, and quality-guaranteed upper bound for the RKP based on the decomposition property of its solution set. We then devise an efficient lifting method by applying the proposed upper bound to lifting problems.

Youngjoo Roh, Junyoung Kim*, Kyungsik Lee*. (2025). "Lifting cover inequalities for the robust knapsack problem." Operations Research Letters. Volume 61, 107301. https://doi.org/10.1016/j.orl.2025.107301

A branch-and-price approach for airport gate assignment problem with chance constraints

Published in Transportation Research Part B: Methodological, 2023

We propose a network-based integer programming model for this problem, estimating the probability distribution using the historical flight arrival/departure deviation data. Then, we strengthen the model using the concept of gate assignment patterns, and a branch-and-price algorithm is devised to solve the model.

Junyoung Kim, Byungju Goo, Youngjoo Roh, Chungmok Lee*, Kyungsik Lee*. (2023). "A branch-and-price approach for airport gate assignment problem with chance constraints." Transportation Research Part B: Methodological. Volume 168, 1-26. https://doi.org/10.1016/j.trb.2022.12.005

A Hybrid Mathematical Programming-Heuristic Algorithm for a Sustainable Power Grid Maintenance Scheduling

Published in Journal of the Korean Institute of Industrial Engineers (대한산업공학회지), 2022

This paper considers a stochastic job allocation problem inspired by a real-life electric power grid operator.

Jaegwan Joo, Youngjoo Roh, Hyunwoo Park, Jerimi Lee, Chungmok Lee*. (2022). "A Hybrid Mathematical Programming-Heuristic Algorithm for a Sustainable Power Grid Maintenance Scheduling." Journal of the Korean Institute of Industrial Engineers. 48(1), 13-34. https://doi.org/10.7232/jkiie.2022.48.1.013