Ann-Brith Strömberg

Approximating the Pareto frontier for bi-objective preventive maintenance and workshop scheduling. A Lagrangean lower bounding methodology for evaluating contracting forms

  • Gabrijela Obradović
  • Ann-Brith Strömberg
  • Felix Held
    • Categories (Mixed) Integer Linear Programming, Scheduling Tags , , ,

    Effective planning of preventive maintenance plays an important role in maximizing the operational readiness of any industrial system. We consider an operating system and a maintenance workshop governed by two stakeholders who collaborate based on a mutual contract: components of the operating system that need maintenance are sent to the maintenance workshop, where necessary maintenance … Read more

    An enhanced mathematical model for optimal simultaneous preventive maintenance scheduling and workshop planning

  • Gabrijela Obradović
  • Ann-Brith Strömberg
    • Categories (Mixed) Integer Linear Programming, Multi-Criteria Optimization, Scheduling

    For a system to stay operational, maintenance of its components is required and to maximize the operational readiness of a system, preventive maintenance planning is essential. There are two stakeholders—a system operator and a maintenance workshop—and a contract regulating their joint activities. Each contract leads to a bi-objective optimization problem. Components that require maintenance are … Read more

    Scheduling optimization of a real flexible job shop including side constraints regarding maintenance, fixtures, and night shifts

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

    We present a generic iterative scheduling procedure for the scheduling of a real flexible job shop, the so-called multitask cell at GKN Aerospace Engine Systems in Sweden. A time-indexed formulation of the problem is presented including side constraints regarding preventive maintenance, fixture availability, and unmanned night shifts. This paper continues the work in Thörnblad et … Read more

    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

    The opportunistic replacement problem: analysis and case studies

  • Torgny Almgren
  • Niclas Andreasson
  • Adam Wojciechowski
  • Michael Patriksson
  • Ann-Brith Strömberg
    • Categories (Mixed) Integer Linear Programming, Scheduling Tags , , , , ,

    We consider an optimization model for determining optimal opportunistic maintenance (that is, component replacement) schedules when data is deterministic. This problem generalizes that of Dickman, Epstein, and Wilamowsky [21] and is a natural starting point for the modelling of replacement schedules when component lives are non-deterministic. We show that this basic opportunistic replacement problem is … Read more