dynamic discretization discovery

Optimizing Expeditionary Logistics: Dynamic Discretization for Fleet Management

  • Haden Boone
  • Mathieu Dahan
    • Categories (Mixed) Integer Linear Programming, Network Optimization, Production and Logistics Tags , , ,

    We introduce the Expeditionary Logistics Network Design Problem (ELNDP), a new formulation for operational-level planning in expeditionary environments where multi-modal vehicle coordination is critical and penalties for unmet demand dominate transportation costs. ELNDP extends the classical Scheduled Service Network Design Problem by incorporating flexible commodity sourcing and heterogeneous vehicle capabilities, both essential in military logistics. … Read more

    Arc-Based Dynamic Discretization Discovery for Continuous-Time Service Network Design

  • Alexander Helber
    • Categories Combinatorial Optimization, Network Optimization, Transportation Tags , , ,

    In the continuous time service network design problem, a freight carrier decides the path of shipments in their network as well as the dispatch times of the vehicles transporting the shipments. State-of-the-art algorithms to solve this problem are based on the dynamic discretization discovery framework. These algorithms solve a relaxation of the problem using a … Read more

    New Dynamic Discretization Discovery Strategies for Continuous-Time Service Network Design

  • Shengnan Shu
  • Zhou Xu
  • Roberto Baldacci
    • Categories Applications - OR and Management Sciences, Integer Programming, Network Optimization Tags , , ,

    Service Network Design Problems (SNDPs) are prevalent in the freight industry. While the classic SNDP is defined on a discretized planning horizon with integral time units, the Continuous-Time SNDP (CTSNDP) uses a continuous-time horizon to avoid discretization errors. Existing CTSNDP algorithms primarily rely on the Dynamic Discretization Discovery (DDD) framework, which iteratively refines discretization and … Read more

    Cross-Dock Trailer Scheduling with Workforce Constraints: A Dynamic Discretization Discovery Approach

  • Ritesh Ojha
  • Alan L. Erera
    • Categories (Mixed) Integer Linear Programming, Scheduling Tags , ,

    LTL freight carriers operate consolidation networks that utilize cross-docking terminals to facilitate thetransfer of freight between trailers and enhance trailer utilization. This research addresses the problem ofdetermining an optimal schedule for unloading inbound trailers at specific unloading doors using teams ofdock workers. The optimization objective is chosen to ensure that outbound trailers are loaded with … Read more

    Dynamic Discretization Discovery Algorithms for Time-Dependent Shortest Path Problems

  • Natashia Boland
  • George L. Nemhauser
  • Martin Savelsbergh
  • Edward He
    • Categories Network Optimization, Transportation Tags , , , , ,

    Finding a shortest path in a network is an iconic optimization problem. We focus on settings in which the travel time on an arc in the network depends on the time at which traversal of the arc begins. In such settings, reaching the sink as early as possible is not the only objective of interest. … Read more

    Interval-based Dynamic Discretization Discovery for Solving the Continuous-Time Service Network Design Problem

  • Natashia Boland
  • Mike Hewitt
  • Luke Marshall
  • Martin Savelsbergh
    • Categories (Mixed) Integer Linear Programming, Transportation Tags

    We introduce an effective and efficient iterative algorithm for solving the Continuous-Time Service Network Design Problem. The algorithm achieves its efficiency by carefully and dynamically refining partially time-expanded network models so that only a small number of small integer programs, defined over these networks, need to be solved. An extensive computational study shows that the … Read more

    Solving Time Dependent Traveling Salesman Problems with Time Windows

  • Natashia Boland
  • Mike Hewitt
  • Martin Savelsbergh
  • Duc Minh Vu
    • Categories Transportation Tags , , ,

    We present a new solution approach for the Time Dependent Traveling Salesman Prob- lem with Time Windows. This problem considers a salesman who departs from his home, has to visit a number of cities within a pre-determined period of time, and then returns home. The problem allows for travel times that can depend on the … Read more