Assessment of systemic vulnerabilities in container shipping networks with consideration of transhipment

  • Pablo E. Achurra-Gonzalez
  • Panagiotis Angeloudis
  • Nils Goldbeck
  • Daniel J. Graham
  • Marc Stettler
  • Konstantinos Zavitsas
    • Categories Game Theory, Supply Chain Management, Transportation

    The global container shipping network is vital to international trade. Current techniques for its vulnerability assessment are constrained due to the lack of historical disruption data and computational limitations due to typical network sizes. We address these modelling challenges by developing a new framework, composed by game-theoretic attacker-defender model and a cost-based container assignment model … Read more

    Predicting the vibroacoustic quality of steering gears

  • Paul Alexandru Bucur
  • Philipp Hungerländer
  • Klaus Frick
    • Categories Data-Mining, Mechanical Engineering, Statistics Tags , , ,

    In the daily operations of ThyssenKrupp Presta AG, ball nut assemblies (BNA) undergo a vibroacoustical quality test and are binary classified based on their order spectra. In this work we formulate a multiple change point problem and derive optimal quality intervals and thresholds for the order spectra that minimize the number of incorrectly classified BNA. … Read more

    A conjugate gradient-based algorithm for large-scale quadratic programming problem with one quadratic constraint

  • Maziar Salahi
  • Akram Taati
    • Categories Global Optimization, Quadratic Programming Tags , ,

    In this paper, we consider the nonconvex quadratically constrained quadratic programming (QCQP) with one quadratic constraint. By employing the conjugate gradient method, an efficient algorithm is proposed to solve QCQP that exploits the sparsity of the involved matrices and solves the problem via solving a sequence of positive definite system of linear equations after identifying … Read more

    Design, Implementation and Simulation of an MPC algorithm for Switched Nonlinear Systems under Combinatorial Constraints

  • Angelika Altmann-Dieses
  • Moritz Diehl
  • Sebastian Sager
  • Adrian Bürger
  • Clemens Zeile
    • Categories (Mixed) Integer Nonlinear Programming, Systems governed by Differential Equations Optimization Tags , , , ,

    Within this work, we present a warm-started algorithm for Model Predictive Control (MPC) of switched nonlinear systems under combinatorial constraints based on Combinatorial Integral Approximation (CIA). To facilitate high-speed solutions, we introduce a preprocessing step for complexity reduction of CIA problems, and include this approach within a new toolbox for solution of CIA problems with … Read more

    Leveraging Predictive Analytics to Control and Coordinate Operations, Asset Loading and Maintenance

  • Nagi Gebraeel
  • Xu Andy Sun
  • Murat Yildirim
    • Categories Applications - OR and Management Sciences, Energy, Scheduling Tags , , , ,

    This paper aims to advance decision-making in power systems by proposing an integrated framework that combines sensor data analytics and optimization. Our modeling framework consists of two components: (1) a predictive analytics methodology that uses real-time sensor data to predict future degradation and remaining lifetime of generators as a function of the loading conditions, and … Read more

    Fleet Sizing and Empty Freight Car Allocation

  • Philipp Hungerländer
  • Sebastian Steininger
    • Categories (Mixed) Integer Linear Programming, Applications - OR and Management Sciences, Production and Logistics Tags , , ,

    Empty freight car allocation problems as well as eet sizing problems depict highly important topics in the eld of railway cargo optimization. Fleet sizing is mainly used in order to nd the minimal number of freight cars ( xed costs) needed to operate the transportation network successfully (e.g. satisfy customer demands). After a consignment is transported … Read more

    Why is maximum clique often easy in practice?

  • Austin Buchanan
  • Jose L. Walteros
    • Categories Combinatorial Optimization

    To this day, the maximum clique problem remains a computationally challenging problem. Indeed, despite researchers’ best efforts, there exist unsolved benchmark instances with one thousand vertices. However, relatively simple algorithms solve real-life instances with millions of vertices in a few seconds. Why is this the case? Why is the problem apparently so easy in many … Read more

    Strictly and Γ-Robust Counterparts of Electricity Market Models: Perfect Competition and Nash-Cournot Equilibria

  • Anja Kramer
  • Vanessa Krebs
  • Martin Schmidt
    • Categories Finance and Economics, Game Theory, Robust Optimization Tags , , , ,

    This paper mainly studies two topics: linear complementarity problems for modeling electricity market equilibria and optimization under uncertainty. We consider both perfectly competitive and Nash–Cournot models of electricity markets and study their robustifications using strict robustness and the Γ-approach. For three out of the four combinations of economic competition and robustification, we derive algorithmically tractable … Read more

    The sharpest column: stabilizing column generation for the bin packing problem via a lexicographic pricer

  • Stefano Coniglio
  • Fabio D'Andreagiovanni
  • Fabio Furini
    • Categories Combinatorial Optimization, Integer Programming

    In spite of being an extremely successful method to tackle mathematical programs involving a very large number of variables, Column Generation (CG) is known to suffer from stabilization issues which can slow down its convergence significantly. In this article, we propose a new parameter-free stabilization technique for CG based on solving a lexicographic pricing problem. … Read more

    Efficient Solution of Maximum-Entropy Sampling Problems

  • Kurt M. Anstreicher
    • Categories (Mixed) Integer Nonlinear Programming, Convex Optimization, Statistics Tags , ,

    We consider a new approach for the maximum-entropy sampling problem (MESP) that is based on bounds obtained by maximizing a function of the form ldet M(x) over linear constraints, where M(x)is linear in the n-vector x. These bounds can be computed very efficiently and are superior to all previously known bounds for MESP on most … Read more