Kristin Braun

Modeling Binary Relations in Piecewise-Linear Approximations

  • Kristin Braun
  • Robert Burlacu
  • Tobias Kuen
  • kristinarolsing
    • Categories Combinatorial Optimization, Global Optimization Theory, Nonlinear Optimization Tags , , , , ,

    Over the last decades, using piecewise-linear mixed-integer relaxations of nonlinear expressions has become a strong alternative to spatial branching for solving mixed-integer nonlinear programs. Since these relaxations give rise to large numbers of binary variables that encode interval selections, strengthening them is crucial. We investigate how to exploit the resulting combinatorial structure by integrating cutting-plane … Read more

    Benchmarking Piecewise Linear Reformulations for MINLPs: A Computational Study Based on the Open-Source Framework PWL-T-Rex

  • Kristin Braun
  • Robert Burlacu
    • Categories (Mixed) Integer Nonlinear Programming Tags , , ,

    Solving mixed-integer nonlinear problems by means of piecewise linear relaxations has emerged as a reasonable alternative to the commonly used spatial branch-and-bound. These relaxations have been modeled by various mixed-integer models in recent decades. The idea is to exploit the availability of mature solvers for mixed-integer problems. In this work, we implement a framework that … Read more

    Minimizing delays of patient transports with incomplete information: A modeling approach based on the Vehicle Routing Problem

  • Dennis Adelhütte
  • Kristin Braun
  • Frauke Liers
  • Sebastian Tschuppik
    • Categories Applications - OR and Management Sciences, Robust Optimization Tags , , , ,

    We investigate a challenging task in ambulatory care, the minimizing of delays of patient transports. In practice, a limited number of vehicles is available for non-rescue transports. Furthermore, the dispatcher rarely has access to complete information when establishing a transport plan for dispatching the vehicles. If additional transport is requested on demand then schedules need … Read more