Applications – OR and Management Sciences

Optimal Route Planning for Orienteering: Branch-and-Cut with Terrain Cost Surfaces and Fatigue

Categories (Mixed) Integer Linear Programming, Branch and Cut Algorithms, Transportation

We address the problem of optimal route planning for competitive orien- teering on real terrain. A Geographic Information System (GIS) pipeline transforms orienteering map data and digital terrain models into a fully asymmetric cost matrix that captures directional slope costs (via the Minetti metabolic model) and cumulative athlete fatigue. The resulting problem, the Asymmetric Orienteering … Read more

Exact Branch-and-Price Algorithm for Live Operating Room Reoptimization

Categories (Mixed) Integer Linear Programming, Multi-Criteria Optimization, Scheduling Tags , , , ,

Live reoptimization of operating room schedules is required to cope with disruptions such as emergency arrivals and deviations in surgery durations under strict time limits. The resulting problem can be formulated as a large-scale Resource Constrained Project Scheduling Problem (RCPSP). While exact optimization methods are attractive in this context due to their ability to provide … Read more

Optimal Batching and In-Building Delivery Routing with Capacitated Residential Parcel Lockers

Categories Production and Logistics, Transportation Tags , , ,

Residential parcel lockers (RPLs), unlike their public counterparts, facilitate secure parcel delivery to occupants of private apartment and condominium buildings in urban areas. In this work, we consider the perspective of a last-mile parcel carrier that has access to an RPL in the lobby of a high-rise residential building. Motivated by growing e-commerce demand, we … Read more

Computing diverse solutions to optimization problems

Categories (Mixed) Integer Linear Programming, Applications - OR and Management Sciences, Combinatorial Optimization Tags , ,

Classical optimization methods determine a single optimal or near-optimal solution for a decision problem. In many applications, however, the decision maker is interested in evaluating a pool of high-quality solutions, to encode fairness-oriented criteria or to obtain a portfolio of alternatives to use in case of unexpected scenarios. In this paper, we consider the problem … Read more

A Lifting-and-Splitting Framework for Risk-Averse Distributionally Robust Multi-Item Newsvendor Problems

Categories Robust Optimization, Semi-definite Programming, Supply Chain Management

Risk-averse distributionally robust multi-item newsvendor problems provide a fundamental model for inventory decisions under demand uncertainty, limited distributional information, and downside-risk concerns. We study this problem under mean-covariance demand ambiguity, where the decision maker maximizes the worst-case conditional value-at-risk of profit. While cross-item demand correlations are important for portfolio-level inventory decisions, they are difficult to … Read more

A Numerically-safe Branch-Price-and-Cut Algorithm for the Length-Constrained Cycle Partition Problem

Categories (Mixed) Integer Linear Programming, Applications - OR and Management Sciences, Dynamic Programming Tags , , , ,

The length-constrained cycle partition problem (LCCP) is a graph optimization problem in which a set of nodes must be partitioned into a minimum number of cycles. Every node is associated with a critical time and the length of every cycle must not exceed the critical time of any node in the cycle. We formulate LCCP … Read more

Integrating Power Profile Optimization with Timetabling for Underground Train Networks

Categories (Mixed) Integer Linear Programming, Polyhedra, Transportation Tags , , ,

We study energy-efficient operation of underground train networks, where energy from regenerative braking is usable only if another train in the same electrically isolated subnetwork accelerates simultaneously. Timetabling models for this setting typically fix one velocity profile per leg and running time, which limits the matching of braking and accelerating phases. We drop this assumption … Read more

A Dynamic-Programming Labeling Approach to Hydrogen-Powered Route Selection in Aviation Networks

Categories Airline Optimization, Applications - OR and Management Sciences Tags , ,

We study passenger routing in an aviation network that blends hydrogen‐ and kerosene‐powered aircraft. Under our assumptions, hydrogen enables carbon‐free short‐ and medium‐haul flights but requires capital‐intensive supply facilities, which lead to varying prices and availabilities of hydrogen at specific airports, creating strong interdependencies between routing, technology choice, and infrastructure availability. To capture these trade‐offs, … Read more

Route `Em and Count `Em: A Two-Stage Stochastic Programming Model for Anti-Submarine Operations

Categories (Mixed) Integer Linear Programming, Stochastic Programming, Transportation Tags , , ,

Tracking targets in undersea warfare requires successful detection by an active search asset. Maximizing detection likelihood requires strategic placement and routing of the search assets in the search region over the planning horizon. We develop a two-stage stochastic integer programming model that maximizes the expected total reward for target detections under uncertainty in target motion … Read more

GPU-accelerated superiorization on constrained physical problems with SupPy

Categories Applications - OR and Management Sciences, Biomedical Applications, Constrained Nonlinear Optimization Tags , , , , ,

The superiorization method (SM) is situated between feasibility-seeking and constrained optimization. Instead of aiming at the minimum of a given objective function over a constraint set, it seeks a feasible point at which the objective function value is reduced — though not necessarily minimal — compared to that reached by the feasibility-seeking algorithm alone. This … Read more