Transportation

Exact and heuristic approaches to reschedule helicopter flights for personnel transportation in the oil industry

  • Yan Bastos
  • Jonathan De La Vega
  • Reinaldo Morabito
  • Pedro Munari
  • Roberto Tavares
  • Paulo César Ribas
  • Thiago Vieira
    • Categories Transportation Tags , , , , ,

    This paper addresses a real-life short-term rescheduling problem of helicopter flights from one onshore airport to several maritime units in the context of the oil industry. This is a complex and challenging problem to solve because of the particular characteristics observed in practice, such as pending flights transferred from previous days with different recovering priorities, … Read more

    An Integer L-shaped algorithm for the vehicle routing problem with time windows and stochastic demands

  • Jonathan De La Vega
  • Reinaldo Morabito
  • Pedro Munari
  • Fernando Ordóñez
  • Michel Gendreau
    • Categories Transportation

    This paper addresses the vehicle routing problem with time windows and stochastic demands (VRPTWSD). The problem is modeled as a two-stage stochastic program with recourse, in which routes are designed in the first stage and executed in the second. A failure occurs if the load of the vehicle is insufficient to meet the observed demand … Read more

    Branch-and-Refine for Solving Time-Dependent Problems

  • Armin Fügenschuh
  • Fabian Gnegel
    • Categories Combinatorial Optimization, Integer Programming, Transportation Tags , , ,

    One of the standard approaches for solving time-dependent discrete optimization problems, such as the traveling salesman problem with time-windows or the shortest path problem with time-windows, is to derive a so-called time-indexed formulation. If the problem has an underlying structure that can be described by a graph, the time-indexed formulation is usually based on a … Read more

    Vehicle Repositioning under Uncertainty

  • Qinshen Tang
  • Yu Zhang
  • Minglong Zhou
    • Categories Applications - OR and Management Sciences, Robust Optimization, Transportation Tags , ,

    We consider a general multi-period repositioning problem in vehicle-sharing networks such as bicycle-sharing systems, free-float car-sharing systems, and autonomous mobility-on-demand systems. This problem is subject to uncertainties along multiple dimensions – including demand, travel time, and repositioning duration – and faces several operational constraints such as the service level and cost budget. We propose a … Read more

    A multicommodity flow model for rerouting and retiming trains in real-time to reduce reactionary delay in complex station areas

  • Matthias Ehrgott
  • Stephen J. Maher
  • Edwin Reynolds
  • Anthony Patman
  • Judith Y.T. Wang
    • Categories Transportation Tags , , ,

    By rerouting and retiming trains in real-time, the propagation of reactionary delay in complex station areas can be reduced. In this study, we propose a new optimisation model and solution algorithm that can be used to determine the best combination of route and schedule changes to make. Whilst several models have been proposed to tackle … Read more

    Interdependence and Integration among Components of the Airline Scheduling Process: A State-of-the-Art Review

  • Divyam Aggarwal
  • Michael T. M. Emmerich
  • Dhish K. Saxena
    • Categories Airline Optimization, Scheduling, Transportation Tags , , , , , ,

    Over the last few decades, the Airline Scheduling Process (ASP) has received an unprecedented attention from airliners and operations research society. Conventionally, the Airline Scheduling Process is decomposed into four sub-problems namely-Schedule Generation, Fleet Assignment, aircraft Routing, and Crew Scheduling which are solved sequentially in order to incorporate tractability and feasibility in the overall process. … Read more

    The Multi-Stop Station Location Problem

  • Miriam Ganz
  • Erik Mühmer
  • Felix J. L. Willamowski
    • Categories Approximation Algorithms, Network Optimization, Transportation Tags , , , ,

    We introduce the (directed) multi-stop station location problem. The goal is to install stations such that ordered (multi-)sets of stops can be traversed with respect to range restrictions that are reset whenever a station is visited. Applications arise in telecommunications and transportation, e.g., charging station placement problems. The problem generalizes several network optimization problems such … Read more

    Mathematical Optimization and Machine Learning for Efficient Urban Traffic

  • Johanna Bethge
  • Maximilian Merkert
  • Sebastian Sager
  • Anton Savchenko
  • Rolf Findeisen
  • Do Duc Le
  • Hannes Rewald
  • Stephan Sorgatz
    • Categories (Mixed) Integer Nonlinear Programming, Control Applications, Transportation Tags , , , , , ,

    Traffic jams cause economical damage which has been estimated between 10 and 100 billion Euros per year in Germany, also due to inefficient urban traffic. It is currently open how the situation will change with upcoming technological advances in autonomous and electric mobility. On the one hand, autonomous cars may lead to an increased number … Read more

    Optimizing Drone-Assisted Last-Mile Deliveries: The Vehicle Routing Problem with Flexible Drones

  • Ilke Bakir
  • Gizem Ozbaygin
    • Categories Network Optimization, Transportation

    The ever-widening acceptance and deployment of drones in last-mile distribution continue to increase the need for planning and managing the delivery operations involving drones effectively. Motivated by the growing interest towards drone-assisted last-mile transportation, we study a hybrid delivery system in which (multiple) trucks and (multiple) drones operate in tandem. In particular, we introduce the … Read more

    Service Network Design for Same-Day Delivery with Hub Capacity Constraints

  • Haotian Wu
  • Ian Herszterg
  • Martin Savelsbergh
  • Yixiao Huang
    • Categories Applications - OR and Management Sciences, Transportation Tags , , ,

    We study a new service network design problem for an urban same-day delivery system in which the number of vehicles that can simultaneously load or unload at a hub is limited. Due to the presence of both time constraints for the commodities and capacity constraints at the hubs, it is no longer guaranteed that a … Read more