Revealing Decision Conservativeness Through Inverse Distributionally Robust Optimization
Qi Li, Zhirui Liang, Andrey Bernstein, Yury Dvorkin
TL;DR
This work tackles the problem of inferring a decision-maker's conservativeness in Wasserstein DRO by observing the decisions produced by Forward DRO (F-DRO). It introduces Inverse DRO (I-DRO), a KKT-based bi-linear formulation that recovers the ambiguity radius $ε$ and provides existence, uniqueness, and necessary/sufficient conditions for exact recovery. The authors prove theoretical guarantees and identify three potential failure modes, then validate the approach on power-system DC-OPF problems, including an IEEE 5-bus case and NYISO 11-zone data, demonstrating accurate recovery and practical computation times. The results highlight the method's potential to forecast or replicate conservative decision-making in uncertain environments, with broader applicability beyond power systems when the forward model exhibits DRO-like structure.
Abstract
This paper introduces Inverse Distributionally Robust Optimization (I-DRO) as a method to infer the conservativeness level of a decision-maker, represented by the size of a Wasserstein metric-based ambiguity set, from the optimal decisions made using Forward Distributionally Robust Optimization (F-DRO). By leveraging the Karush-Kuhn-Tucker (KKT) conditions of the convex F-DRO model, we formulate I-DRO as a bi-linear program, which can be solved using off-the-shelf optimization solvers. Additionally, this formulation exhibits several advantageous properties. We demonstrate that I-DRO not only guarantees the existence and uniqueness of an optimal solution but also establishes the necessary and sufficient conditions for this optimal solution to accurately match the actual conservativeness level in F-DRO. Furthermore, we identify three extreme scenarios that may impact I-DRO effectiveness. Our case study applies F-DRO for power system scheduling under uncertainty and employs I-DRO to recover the conservativeness level of system operators. Numerical experiments based on an IEEE 5-bus system and a realistic NYISO 11-zone system demonstrate I-DRO performance in both normal and extreme scenarios.
