Applications – OR and Management Sciences

An integrated assignment, routing, and speed model for roadway mobility and transportation with environmental, efficiency, and service goals

  • Tommaso Giovannelli
  • Luis Nunes Vicente
    • Categories Transportation Tags , , ,

    Managing all the mobility and transportation services with autonomous vehicles for users of a smart city requires determining the assignment of the vehicles to the users and their routing in conjunction with their speed. Such decisions must ensure low emission, efficiency, and high service quality by also considering the impact on traffic congestion caused by … Read more

    Dual Bounds from Decision Diagram-Based Route Relaxations: An Application to Truck-Drone Routing

  • Z Tang
  • Willem-Jan van Hoeve
    • Categories Integer Programming, Transportation Tags , , , ,

    For vehicle routing problems, strong dual bounds on the optimal value are needed to develop scalable exact algorithms, as well as to evaluate the performance of heuristics. In this work, we propose an iterative algorithm to compute dual bounds motivated by connections between decision diagrams (DDs) and dynamic programming (DP) models used for pricing in … Read more

    Using Neural Networks to Guide Data-Driven Operational Decisions

  • Ningyuan Chen
  • Saman Lagzi
    • Categories Applications - OR and Management Sciences, Supply Chain Management, Yield Management Tags , , ,

    We propose to use Deep Neural Networks to solve data-driven stochastic optimization problems. Given the historical data of the observed covariate, taken decision, and the realized cost in past periods, we train a neural network to predict the objective value as a function of the decision and the covariate. Once trained, for a given covariate, … Read more

    A Machine Learning Approach to Solving Large Bilevel and Stochastic Programs: Application to Cycling Network Design

  • Bo Lin
    • Categories Integer Programming, Stochastic Programming, Transportation Tags , , , ,

    We present a novel machine learning-based approach to solving bilevel programs that involve a large number of independent followers, which as a special case include two-stage stochastic programming. We propose an optimization model that explicitly considers a sampled subset of followers and exploits a machine learning model to estimate the objective values of unsampled followers. … Read more

    Decarbonizing OCP

  • Dimitris Bertsimas
  • Ryan Cory-Wright
  • Vassilis Digalakis Jr
    • Categories Applications - OR and Management Sciences, Production and Logistics, Robust Optimization

    Problem definition: We present our collaboration with the OCP Group, one of the world’s largest producers of phosphate and phosphate-based products, in support of a green initiative designed to reduce OCP’s carbon emissions significantly. We study the problem of decarbonizing OCP’s electricity supply by installing a mixture of solar panels and batteries to minimize its … Read more

    On solving the Cross-dock Door Assignment Problem, CDAP

  • Laureano F. Escudero
  • M. Araceli Garin
  • Aitziber Unzueta
    • Categories Applications - OR and Management Sciences, Production and Logistics Tags , , , ,

    A class of strong lower bounds on the solution value of a Linearized Integer Programming (LIP) reformulation is introduced for the binary quadratic optimization model to assign origin and destination nodes to strip and stack doors, resp., in a cross-dock infrastructure, whose goal is to minimize the transportation cost of the commodities to be handled … Read more

    Computational complexity of decomposing a symmetric matrix as a sum of positive semidefinite and diagonal matrices

  • Levent Tunçel
  • Stephen A. Vavasis
  • jingye xu
    • Categories Finance and Economics, Statistics Tags

    We study several variants of decomposing a symmetric matrix into a sum of a low-rank positive semidefinite matrix and a diagonal matrix. Such decompositions have applications in factor analysis and they have been studied for many decades. On the one hand, we prove that when the rank of the positive semidefinite matrix in the decomposition … Read more

    Dynamic Rebalancing Optimization for Bike-sharing Systems: A Modeling Framework and Empirical Comparison

  • Jiaqi Liang
  • Sanjay Dominik Jena
  • Andrea Lodi
    • Categories (Mixed) Integer Linear Programming, Applications - OR and Management Sciences, Transportation Tags , , ,

    Bike-sharing systems have been implemented in multiple major cities, offering a low-cost and environmentally friendly transportation alternative to vehicles. Due to the stochastic nature of customer trips, stations are often unbalanced, resulting in unsatisfied demand. As a remedy, operators employ trucks to rebalance bikes among unbalanced stations. Given the complexity of the dynamic rebalancing planning, … Read more

    Production Theory for Constrained Linear Activity Models

  • Somdeb Lahiri
    • Categories Finance and Economics, Linear Programming, Production and Logistics Tags , ,

    The purpose of this paper is to generalize the framework of activity analysis discussed in Villar (2003) and obtain similar results concerning solvability. We generalize the model due to Villar (2003), without requiring any dimensional requirements on the activity matrices and by introducing a model of activity analysis in which each activity may (or may … Read more

    Temporal Bin Packing with Half-Capacity Jobs

  • Christopher Muir
  • Luke Marshall
  • Alejandro Toriello
    • Categories (Mixed) Integer Linear Programming, Polyhedra, Scheduling Tags , , , ,

    Motivated by applications in cloud computing, we study a temporal bin packing problem with jobs that occupy half of a bin’s capacity. An instance is given by a set of jobs, each with a start and end time during which it must be processed, i.e., assigned to a bin. A bin can accommodate two jobs … Read more