mixed-integer programming

Exact and heuristic approaches to reschedule helicopter flights for personnel transportation in the oil industry

  • Yan Bastos
  • Jonathan De La Vega
  • Reinaldo Morabito
  • Pedro Munari
  • Roberto Tavares
  • Paulo César Ribas
  • Thiago Vieira
    • Categories Transportation Tags , , , , ,

    This paper addresses a real-life short-term rescheduling problem of helicopter flights from one onshore airport to several maritime units in the context of the oil industry. This is a complex and challenging problem to solve because of the particular characteristics observed in practice, such as pending flights transferred from previous days with different recovering priorities, … Read more

    Mixed Integer Bilevel Optimization with k-optimal Follower: A Hierarchy of Bounds

  • Xueyu Shi
  • Oleg A. Prokopyev
  • Ted K. Ralphs
    • Categories (Mixed) Integer Linear Programming, Game Theory Tags ,

    We consider mixed integer bilevel linear optimization problems in which the decision variables of the lower-level (follower’s) problem are all binary. We propose a general modeling and solution framework motivated by the practical reality that in a Stackelberg game, the follower does not always solve their optimization problem to optimality. They may instead implement a … Read more

    Combination Chemotherapy Optimization

  • Temitayo Ajayi
  • Seyedmohammadhossein Hosseinian
  • Andrew J. Schaefer
  • Clifton D. Fuller
    • Categories (Mixed) Integer Linear Programming, Biomedical Applications Tags , ,

    Chemotherapy is one of the primary modalities of cancer treatment. Chemotherapy drug administration is a complex problem that often requires expensive clinical trials to evaluate potential regimens. One way to alleviate this burden and better inform future trials is to build reliable models for drug administration. Previous chemotherapy optimization models have mainly relied on optimal … Read more

    Solving Previously Unsolved MIP Instances with ParaSCIP on Supercomputers by using up to 80,000 Cores

  • Tobias Achterberg
  • Timo Berthold
  • Stefan Heinz
  • Thorsten Koch
  • Yuji Shinano
  • Michael Winkler
    • Categories (Mixed) Integer Linear Programming, Parallel Algorithms, Problem Solving Environments Tags , , , , , ,

    Mixed-integer programming (MIP) problem is arguably among the hardest classes of optimization problems. This paper describes how we solved 21 previously unsolved MIP instances from the MIPLIB benchmark sets. To achieve these results we used an enhanced version of ParaSCIP, setting a new record for the largest scale MIP computation: up to 80,000 cores in … Read more

    Exact and Approximation Algorithms for Sparse PCA

  • Yongchun Li
  • Weijun Xie
    • Categories Integer Programming Tags , , , , ,

    Sparse Principal Component Analysis (SPCA) is designed to enhance the interpretability of traditional Principal Component Analysis (PCA) by optimally selecting a subset of features that comprise the first principal component. Given the NP-hard nature of SPCA, most current approaches resort to approximate solutions, typically achieved through tractable semidefinite programs (SDPs) or heuristic methods. To solve SPCA to … Read more

    Two-Stage Sort Planning for Express Parcel Delivery

  • Alan L. Erera
  • Alejandro Toriello
  • Reem Khir
    • Categories Production and Logistics Tags , ,

    Recent years have brought significant changes in the operations of parcel transportation services, most notably due to the growing demand for e-commerce worldwide. Parcel sortation systems are used within sorting facilities in these transportation networks to enable the execution of effective consolidation plans with low per-unit handling and shipping costs. Designing and implementing effective parcel … Read more

    Solving Large-Scale Sparse PCA to Certifiable (Near) Optimality

  • Dimitris Bertsimas
  • Ryan Cory-Wright
  • Jean Pauphilet
    • Categories (Mixed) Integer Nonlinear Programming, Semi-definite Programming, Statistics Tags , , ,

    Sparse principal component analysis (PCA) is a popular dimensionality reduction technique for obtaining principal components which are linear combinations of a small subset of the original features. Existing approaches cannot supply certifiably optimal principal components with more than $p=100s$ of variables. By reformulating sparse PCA as a convex mixed-integer semidefinite optimization problem, we design a … Read more

    A Distributionally Robust Optimization Approach for Stochastic Elective Surgery Scheduling with Limited Intensive Care Unit Capacity

  • Rema Padman
  • Karmel S. Shehadeh
    • Categories (Mixed) Integer Linear Programming, Scheduling, Stochastic Programming Tags , , , , ,

    In this paper, we study the decision process of assigning elective surgery patients to available surgical blocks in multiple operating rooms (OR) under random surgery durations, random postoperative length-of-stay in the intensive care unit (ICU), and limited capacity of ICU. The probability distributions of random parameters are assumed to be ambiguous, and only the mean … Read more

    Mathematical Optimization and Machine Learning for Efficient Urban Traffic

  • Johanna Bethge
  • Maximilian Merkert
  • Sebastian Sager
  • Anton Savchenko
  • Rolf Findeisen
  • Do Duc Le
  • Hannes Rewald
  • Stephan Sorgatz
    • Categories (Mixed) Integer Nonlinear Programming, Control Applications, Transportation Tags , , , , , ,

    Traffic jams cause economical damage which has been estimated between 10 and 100 billion Euros per year in Germany, also due to inefficient urban traffic. It is currently open how the situation will change with upcoming technological advances in autonomous and electric mobility. On the one hand, autonomous cars may lead to an increased number … Read more

    A Model of Supply-Chain Decisions for Resource Sharing with an Application to Ventilator Allocation to Combat COVID-19

  • Sanjay Mehrotra
  • Hamed Rahimian
  • Masoud Barah
  • Fengqiao Luo
  • Karolina Schantz
    • Categories (Mixed) Integer Linear Programming, Applications - OR and Management Sciences, Stochastic Programming Tags , , , , ,

    We present a stochastic optimization model for allocating and sharing a critical resource in the case of a pandemic. The demand for different entities peaks at different times, and an initial inventory for a central agency is to be allocated. The entities (states) may share the critical resource with a different state under a risk-averse … Read more