Gizem Ozbaygin

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

    An Exact Solution Approach for the Inventory Routing Problem with Time Windows

  • Esra Koca
  • Gizem Ozbaygin
  • Hande Yaman
    • Categories Applications - OR and Management Sciences, Production and Logistics, Transportation

    The inventory routing problem (IRP) is an integrated inventory and transportation planning problem that jointly determines the replenishment schedules for a given set of retailers, and the routing decisions for a supplier that distributes a product to the retailers over a finite planning horizon typically consisting of multiple periods. In the classical IRP, retailers are … Read more

    An Iterative Re-optimization Framework for the Dynamic Vehicle Routing Problem with Roaming Delivery Locations

  • Gizem Ozbaygin
  • Martin Savelsbergh
    • Categories Network Optimization, Transportation Tags , , ,

    Branch-and-price has established itself as an effective solution methodology for a wide variety of planning problems. We investigate its potential as a solution method- ology for solving operational problems. Specifically, we explore its potential in the context of a dynamic variant of the vehicle routing problem with roaming delivery locations, in which customer itineraries may … Read more

    A Branch-and-Price Algorithm for the Vehicle Routing Problem with Roaming Delivery Locations

  • Oya Ekin Karasan
  • Gizem Ozbaygin
  • Martin Savelsbergh
  • Hande Yaman
    • Categories Integer Programming, Network Optimization, Transportation Tags , , , ,

    We study the vehicle routing problem with roaming delivery locations in which the goal is to find a least-cost set of delivery routes for a fleet of capacitated vehicles and in which a customer order has to be delivered to the trunk of the customer’s car during the time that the car is parked at … Read more

    New Exact Solution Approaches for the Split Delivery Vehicle Routing Problem

  • Oya Ekin Karasan
  • Gizem Ozbaygin
  • Hande Yaman
    • Categories Transportation

    In this study, we propose exact solution methods for the Split Delivery Vehicle Routing Problem (SDVRP). We first give a new vehicle-indexed flow formulation for the problem, and then, a relaxation obtained by aggregating the vehicle-indexed variables over all vehicles. This relaxation may have optimal solutions where several vehicles exchange loads at some customers. We … Read more