Douglas Alem

Crew Scheduling and Routing Problem in Road Restoration via Branch-and-Price Algorithms

  • Alfredo Moreno
  • Pedro Munari
  • Douglas Alem
    • Categories Applications - OR and Management Sciences, Transportation Tags , , , ,

    This paper addresses the single crew scheduling and routing problem in the context of road network repair and restoration, which is critical in assisting complex post-disaster decisions in humanitarian logistics settings. We present three novel formulations for this problem, which are the first suitable for column generation and branch-and-price (BP) algorithms. Specifically, our first formulation … Read more

    Practicable Robust Stochastic Optimization under Divergence Measures

  • Douglas Alem
  • Aakil Caunhye
    • Categories Robust Optimization, Stochastic Programming Tags , , , , ,

    We seek to provide practicable approximations of the two-stage robust stochastic optimization (RSO) model when its ambiguity set is constructed with an f-divergence radius. These models are known to be numerically challenging to various degrees, depending on the choice of the f-divergence function. The numerical challenges are even more pronounced under mixed-integer rst-stage decisions. In … Read more

    ‘Pro-poor’ humanitarian logistics: Prioritizing the vulnerable in allocating relief aid

  • Douglas Alem
  • Tolga Bektas
  • Luciana R. Londe
  • Rafaela Veloso
    • Categories Production and Logistics

    This paper builds on the premise that the most vulnerable areas or groups of people should be protected from disasters by being given priority in humanitarian operations, particularly when there are limited resources available for disaster management. The basis and the development of the paper are strongly aligned with the United Nations’ Sustainable Development Goals … Read more

    The heterogeneous multicrew scheduling and routing problem in road restoration

  • Douglas Alem
  • Pedro Munari
  • Michel Gendreau
  • Alfredo Moreno
    • Categories Applications - OR and Management Sciences, Combinatorial Optimization

    This paper introduces the heterogeneous multicrew scheduling and routing problem (MCSRP) in road restoration. The MCSRP consists of identifying the schedule and route of heterogeneous crews that must perform the restoration of damaged nodes used in the paths to connect a source node to demand nodes in a network affected by extreme events. The objective … Read more

    Decomposition-based algorithms for the crew scheduling and routing problem in road restoration

  • Douglas Alem
  • Pedro Munari
  • Alfredo Moreno
    • Categories Branch and Cut Algorithms

    The crew scheduling and routing problem (CSRP) consists of determining the best route and schedule for a single crew to repair damaged nodes in a network affected by extreme events. The problem also involves the design of paths to connect a depot to demand nodes that become accessible only after the damaged nodes in these … Read more

    The robust vehicle routing problem with time windows: compact formulation and branch-price-and-cut method

  • Douglas Alem
  • Jonathan De La Vega
  • Jacek Gondzio
  • Reinaldo Morabito
  • Pedro Munari
  • Alfredo Moreno
    • Categories Applications - OR and Management Sciences, Robust Optimization, Transportation

    We address the robust vehicle routing problem with time windows (RVRPTW) under customer demand and travel time uncertainties. As presented thus far in the literature, robust counterparts of standard formulations have challenged general-purpose optimization solvers and specialized branch-and-cut methods. Hence, optimal solutions have been reported for small-scale instances only. Additionally, although the most successful methods … Read more

    A Branch-and-Benders-Cut Algorithm for the Road Restoration Crew Scheduling and Routing Problem

  • Douglas Alem
  • Pedro Munari
  • Alfredo Moreno
    • Categories Applications - OR and Management Sciences, Branch and Cut Algorithms, Cutting Plane Approaches Tags , , , ,

    Extreme events such as disasters cause partial or total disruption of basic services such as water, energy, communication and transportation. In particular, roads can be damaged or blocked by debris, thereby obstructing access to certain affected areas. Thus, restoration of the damaged roads is necessary to evacuate victims and distribute emergency commodities to relief centers … Read more

    An Improved Stochastic Optimization Model for Water Supply Pumping Systems in Urban Networks

  • Douglas Alem
  • Jonathan De La Vega
    • Categories Applications - OR and Management Sciences, Stochastic Programming Tags , ,

    This study investigates a pump scheduling problem for the collection, transfer and storage of water in water supply systems in urban networks. The objective of this study is to determine a method to minimize the electricity costs associated with pumping operations. To address the dynamic and random nature of water demand, we propose a two-stage … Read more