Anand Subramanian

Cluster branching for vehicle routing problems

  • Joao Marcos P Silva
  • Eduardo Uchoa
  • Anand Subramanian
    • Categories Applications - OR and Management Sciences, Combinatorial Optimization, Integer Programming Tags , , ,

    This article introduces Cluster Branching, a novel branching strategy for exact algorithms solving Vehicle Routing Problems (VRPs). While branching is crucial for the efficiency of branch-and-bound-based algorithms, existing branching types such as Edge Branching, CutSet Branching, and Ryan&Foster Branching have their limitations. The proposed branching strategy aggregates multiple edge variables into higher-level decision structures corresponding … Read more

    Routing a fleet of unmanned aerial vehicles: a trajectory optimisation-based framework

  • Walton P. Coutinho
  • Jörg Fliege
  • Maria Battarra
  • Anand Subramanian
    • Categories (Mixed) Integer Nonlinear Programming, Applications - OR and Management Sciences, Systems governed by Differential Equations Optimization Tags , ,

    We consider an aerial survey operation in which a fleet of unmanned aerial vehicles (UAVs) is required to visit several locations and then land in one of the available landing sites while optimising some performance criteria, subject to operational constraints and flight dynamics. We aim to minimise the maximum flight time of the UAVs. To … Read more

    Scheduling the Brazilian OR Conference

  • Teobaldo Bulhões
  • Puca Huachi V. Penna
  • Anand Subramanian
  • Rubens Correia
    • Categories Meta Heuristics, Scheduling Tags , ,

    In this paper, we show how to efficiently schedule the Brazilian OR conference using a matheuristic approach. The event has traditionally around 300 presentations across a period of 3 to 4 days, and building a schedule for the technical sessions is an arduous task. The proposed algorithm integrates the concepts of iterated local search and … Read more

    Conference scheduling: a clustering-based approach

  • Teobaldo Bulhões
  • Anand Subramanian
  • Rubens Correia
    • Categories Integer Programming, Scheduling Tags , ,

    Scheduling the technical sessions of scientific events is an arduous task commonly faced by many organizers worldwide. Due the particularities of each conference, there is no consensus regarding the problem definition, and researchers have tackled each specific case individually. Despite their distinct characteristics, one often expects the sessions to be composed of presentations of similar … Read more

    Personnel scheduling during Covid-19 pandemic

  • Manuel Iori
  • Anand Subramanian
  • Giorgio Zucchi
    • Categories (Mixed) Integer Linear Programming, Scheduling Tags , , ,

    This paper addresses a real-life personnel scheduling problem in the context of Covid-19 pandemic, arising in a large Italian pharmaceutical distribution warehouse. In this case study, the challenge is to determine a schedule that attempts to meet the contractual working time of the employees, considering the fact that they must be divided into mutually exclusive … Read more

    Branch-and-Cut approaches for p-Cluster Editing

  • Teobaldo Bulhões
  • Lucídio Cabral
  • Anand Subramanian
  • Gilberto Sousa
    • Categories Branch and Cut Algorithms Tags , ,

    This paper deals with a variant of the well-known Cluster Editing Problem (CEP), more precisely, the \textit{p}-CEP, in which a given input graph should be edited by adding and/or removing edges in such a way that \textit{p} vertex-disjoint cliques (clusters) are generated with the minimum number of editions. We introduce several valid inequalities where some … Read more

    New Benchmark Instances for the Capacitated Vehicle Routing Problem

  • Diego Pecin
  • Artur Alves Pessoa
  • Marcus Poggi de Aragão
  • Anand Subramanian
  • Eduardo Uchoa
  • Thibaut Vidal
    • Categories (Mixed) Integer Linear Programming, Meta Heuristics, Transportation Tags , ,

    The recent research on the CVRP is being slowed down by the lack of a good set of benchmark instances. The existing sets suff er from at least one of the following drawbacks: (i) became too easy for current algorithms; (ii) are too arti cial; (iii) are too homogeneous, not covering the wide range of characteristics found … Read more

    A Branch-and-Bound Algorithm for the Close-Enough Traveling Salesman Problem

  • Walton Coutinho
  • Artur Alves Pessoa
  • Anand Subramanian
  • Roberto do Nascimento
    • Categories Combinatorial Optimization, Second-Order Cone Programming

    This paper deals with the Close-Enough Traveling Salesman Problem (CETSP). In the CETSP, rather than visiting the vertex (customer) itself, the salesman must visit a specific region containing such vertex. To solve this problem, we propose a simple yet effective exact algorithm, based on Branch-and-Bound and Second Order Cone Programming (SOCP). The proposed algorithm was … Read more

    Exact algorithms for the Traveling Salesman Problem with Draft Limits

  • Maria Battarra
  • Artur Alves Pessoa
  • Anand Subramanian
  • Eduardo Uchoa
    • Categories Branch and Cut Algorithms, Integer Programming Tags , , , ,

    This paper deals with the Traveling Salesman Problem (TSP) with Draft Limits (TSPDL), which is a variant of the well-known TSP in the context of maritime transportation. In this recently proposed problem, draft limits are imposed due to restrictions on the port infrastructures. Exact algorithms based on three mathematical formulations are proposed and their performance … Read more

    Improved Bounds for Large Scale Capacitated Arc Routing Problem

  • Rafael Martinelli
  • Marcus Poggi de Aragão
  • Anand Subramanian
    • Categories Combinatorial Optimization, Cutting Plane Approaches, Meta Heuristics Tags , , , ,

    The Capacitated Arc Routing Problem (CARP) stands among the hardest combinatorial problems to solve or to find high quality solutions. This becomes even more true when dealing with large instances. This paper investigates methods to improve on lower and upper bounds of instances on graphs with over two hundred vertices and three hundred edges, dimensions … Read more