Optimization Days 2026

HEC Montréal, Québec, Canada

May 11 — 13, 2026

MB10* - Stochastic and Robust Optimization 1

May 11 2026 15:30 – 17:10

Location: Procter & Gamble (green)

Chaired by Amir Ardestani-Jaafari

4 Presentations

15:30 - 15:55

Competitive bi-level facility location with levels of service and stochastic customers preferences

  • SIMONA MANCINI, speaker, University of Palermo
  • Leandro CALLEGARI-COELHO, Université Laval

We study a competitive bi-level facility location problem with stochastic customer preferences and service levels. Customers choose facilities based on distance and service quality. We propose a single -level reformulation and a three-step deterministic policy (POLU) combining pessimistic, optimistic, and upgrade phases. Results show improved performance over deterministic and single-policy approaches.

15:55 - 16:20

Predictive, Prescriptive Framework for Production Planning in Smart Factories

  • Benedikt Kern, speaker, Concordia University
  • Masoumeh Kazemi-Zanjani, Concordia University

We develop a Predictive-Prescriptive Analytics (PPA) framework for integrated production planning in sensor-driven smart factories (SFs). In the predictive layer, our approach uses sensor data to predict equipment reliability that affects the available production capacity. We explicitly avoid using point predicted deterministic parameters in our model to absorb prediction errors. Instead, we translate predictive uncertainty into covariate conditioned scenarios by exploiting the neighborhood structure of k Nearest Neighbors (kNN) and the leaf proximity structure of Random Forests (RFs). For each sensor state, we compute probability weights over historical outcomes and sample a finite scenario set that feeds a two-stage stochastic programming model. The prescriptive layer then jointly optimizes maintenance actions, production quantities, and machine activations over a short-term planning horizon. As the model grows fast in complexity, we develop a Progressive Hedging (PH) inspired fix-and-optimize approach. We evaluate the performance of our model through several experiment sets and finally assess the value of using our PPA framework relative to a conventional Sample Average Approximation (SAA) approach.

Keywords – Predictive Prescriptive Analytics, Smart Factory, Predictive Maintenance

16:20 - 16:45

Robust Multi-Product Hub Location under Spoilage Uncertainty

  • Brenda Cobena, speaker, HEC
  • Raf Jans, HEC Montréal
  • Sonja Rohmer, HEC Montreal

We address hub location and flow allocation in capacitated agri-food networks distributing multiple perishable products through hubs. A key challenge is that distance-based deterioration is uncertain and varies across products and supplier–hub pairs. To account for this, we develop a budgeted robust optimization framework. Results show tractability and favor lower-deterioration suppliers.

16:45 - 17:10

Stochastic Facility Location with Nonlinear and Uncertain Congestion Costs

  • Amir Ardestani-Jaafari, speaker, University of British Columbia - Okanagan Campus
  • Elnaz Azizi, Smith School of Business, Queen’s University
  • Pooya Hoseinpour, Smith School of Business, Queen’s University
  • Beste Kucukyazici, Smith School of Business, Queen’s University

This paper develops a stochastic facility location framework incorporating nonlinear congestion costs and uncertainty in waiting-time valuation. Using queueing theory and mixed-integer optimization, it compares linear, piecewise-linear, and robust models under minisum and minimax objectives, demonstrating how nonlinear and uncertain congestion significantly influence facility placement, system performance, and decision robustness.