π€ AI Summary
This paper studies the Ordered Median Tree (OMT) location problem: selecting $p$ facilities on an undirected tree network to jointly optimize the ordered weighted average of assignment costs and the inter-facility connection cost. It introduces the ordered median criterion to tree-structured facility location for the first time, proposing a novel model that guarantees theoretical optimality while remaining polynomially solvable. Leveraging an integrated design of dynamic programming, tree traversal, and sorting-based optimization, we develop an exact algorithm with time complexity $O(n^2 k)$, where $n$ is the number of nodes and $k$ is the number of distinct weights in the ordering vector. Extensive experiments across diverse tree topologies demonstrate that our algorithm significantly outperforms classical median- and center-based heuristics, reducing average total cost by 18.7%. These results validate both the modeling efficacy and the practical applicability of the proposed approach.