time-indexed formulation

A competitive iterative procedure using a time-indexed model for solving flexible job shop scheduling problems

  • Torgny Almgren
  • Michael Patriksson
  • Ann-Brith Strömberg
  • Karin Thörnblad
    • Categories (Mixed) Integer Linear Programming, Production and Logistics, Scheduling Tags , , , , , ,

    We investigate the efficiency of a discretization procedure utilizing a time-indexed mathematical optimization model for finding accurate solutions to flexible job shop scheduling problems considering objectives comprising the makespan and the tardiness of jobs, respectively. The time-indexed model is used to find solutions to these problems by iteratively employing time steps of decreasing length. The … Read more

    A new lower bound for one-machine earliness-tardiness scheduling

  • Francis Sourd
    • Categories Scheduling Tags , , , ,

    In one-machine scheduling, MIP time-indexed formulations are often used to provide very good lower bounds through Lagrangian relaxations. In order to get an improved lower bound, we add valid cuts to a time-indexed formulation and show we still have a Lagrangian relaxation that can be solved as a shortest path in a graph. Two branch-and-bound … Read more

    A Lagrangian Heuristic for Satellite Range Scheduling with Resource Constraints

  • Fabrizio Marinelli
  • Salvatore Nocella
  • Fabrizio Rossi
  • Stefano Smriglio
    • Categories 0-1 Programming, Applications - OR and Management Sciences Tags , , , , ,

    The task of scheduling communications between satellites and ground control stations is getting more and more critical since an increasing number of satellites must be controlled by a small set of stations. In such a congested scenario, the current practice, in which experts build hand-made schedules, often leaves a large number of communication requests unserved. … Read more