Eleftheria Kontou – Optimization Online

Betweenness Central Nodes Under Uncertainty: An Absorbing Markov Chain Approach

Published: 2026/05/13

Applications - OR and Management Sciences, Applications - Science and Engineering, Robust Optimization betweenness, Data-Driven Robust Optimization, group betweenness centrality, markov chain, markov chain approximation, markov chain monte carlo, markov chain sample average approximation, stochastic network design

We propose a betweenness centrality measure and algorithms for stochastic networks, where edges can fail and weights vary across realizations, making the most central node random. Our approach models the sequence of reported central nodes as an absorbing Markov chain and measures node importance by the share of pre-absorption time spent at each node. This … Read more

Risk-Averse Stochastic User Equilibrium on Uncertain Transportation Networks

Published: 2026/03/04, Updated: 2026/03/06

Wencheng Bao

Chrysafis Vogiatzis

Eleftheria Kontou

Network Optimization, Robust Optimization, Transportation distributionally robust optimization, Hazard Impacts, risk aversion, stochastic programming, Stochastic User Equilibrium, traffic assignment

Extreme weather events, like flooding, disrupt urban transportation networks by reducing speeds and capacities, and by closing roadways. These hazards create regime-dependent uncertainty in link performance and travel-time distribution tails, challenging conventional traffic assignment that relies on the expectation of cost or mean excess of cost summation. This study develops a risk- and ambiguity-aware traffic … Read more