Aid Allocation for Camp-Based and Urban Refugees with Uncertain Demand and Replenishments

  • Shima Azizi
  • Cem Deniz Caglar Bozkir
  • Andrew C. Trapp
  • O. Erhun Kundakcioglu
  • Ali Kaan Kurbanzade
    • Categories Applications - OR and Management Sciences Tags , , ,

    There are nearly 26 million refugees worldwide seeking safety from persecution, violence, conflict, and human rights violations. Camp-based refugees are those that seek shelter in refugee camps, whereas urban refugees inhabit nearby, surrounding populations. The systems that supply aid to refugee camps may suffer from ineffective distribution due to challenges in administration, demand uncertainty and … Read more

    On Inexact Accelerated Proximal Gradient Methods with Relative Error Rules

  • Yunier Bello-Cruz
  • Max L. N. Gonçalves
  • Nathan Krislock
    • Categories Convex and Nonsmooth Optimization, Nonlinear Optimization Tags , , , , ,

    One of the most popular and important first-order iterations that provides optimal complexity of the classical proximal gradient method (PGM) is the “Fast Iterative Shrinkage/Thresholding Algorithm” (FISTA). In this paper, two inexact versions of FISTA for minimizing the sum of two convex functions are studied. The proposed schemes inexactly solve their subproblems by using relative … Read more

    Parametric analysis of conic linear optimization

  • Guo Jinhai
  • Yan Zizong
  • Li Xiangjun
    • Categories Linear, Cone and Semidefinite Programming, Semi-definite Programming Tags , , , ,

    This paper focuses on the parametric analysis of a conic linear optimization problem with respect to the perturbation of the objective function along many fixed directions. We introduce the concept of the primal and dual conic linear inequality representable sets, which is very helpful for converting the correlation of the parametric conic linear optimization problems … Read more

    Optimising the assignment of swabs and reagents for PCR testing during a viral epidemic

  • Alberto Santini
    • Categories Applications - OR and Management Sciences, Applications - Science and Engineering Tags , ,

    Early large-scale swab testing is a fundamental tool for health authorities to assess the prevalence of a virus and enact appropriate mitigation measures during an epidemic. The COVID-19 pandemic has shown that the availability of chemical reagents required to carry out the tests is often a bottleneck in increasing a country’s testing capacity. Further, demand … Read more

    Towards practical generic conic optimization

  • Chris Coey
  • Juan Pablo Vielma
  • Lea Kapelevich
    • Categories Convex Optimization, Linear, Cone and Semidefinite Programming, Optimization Software and Modeling Systems Tags , , ,

    Many convex optimization problems can be represented through conic extended formulations with auxiliary variables and constraints using only the small number of standard cones recognized by advanced conic solvers such as MOSEK 9. Such extended formulations are often significantly larger and more complex than equivalent conic natural formulations, which can use a much broader class … Read more

    Interdependence and Integration among Components of the Airline Scheduling Process: A State-of-the-Art Review

  • Divyam Aggarwal
  • Michael T. M. Emmerich
  • Dhish K. Saxena
    • Categories Airline Optimization, Scheduling, Transportation Tags , , , , , ,

    Over the last few decades, the Airline Scheduling Process (ASP) has received an unprecedented attention from airliners and operations research society. Conventionally, the Airline Scheduling Process is decomposed into four sub-problems namely-Schedule Generation, Fleet Assignment, aircraft Routing, and Crew Scheduling which are solved sequentially in order to incorporate tractability and feasibility in the overall process. … Read more

    Disk matrices and the proximal mapping for the numerical radius

  • X.Y. Han
  • Adrian Lewis
    • Categories Convex Optimization, Semi-definite Programming Tags , , , ,

    Optimal matrices for problems involving the matrix numerical radius often have fields of values that are disks, a phenomenon associated with partial smoothness. Such matrices are highly structured: we experiment in particular with the proximal mapping for the radius, which often maps n-by-n random matrix inputs into a particular manifold of disk matrices that has … Read more

    Iteration-complexity of an inexact proximal accelerated augmented Lagrangian method for solving linearly constrained smooth nonconvex composite optimization problems

  • Jefferson Gonçalves Melo
  • Renato D.C. Monteiro
  • Hairong Wang
    • Categories Constrained Nonlinear Optimization Tags , , ,

    This paper proposes and establishes the iteration-complexity of an inexact proximal accelerated augmented Lagrangian (IPAAL) method for solving linearly constrained smooth nonconvex composite optimization problems. Each IPAAL iteration consists of inexactly solving a proximal augmented Lagrangian subproblem by an accelerated composite gradient (ACG) method followed by a suitable Lagrange multiplier update. It is shown that … Read more

    Data Approximation by L1 Spline Fits with Free Knots

  • Ziteng Wang
  • Manfei Xie
    • Categories Applications - OR and Management Sciences, Applications - Science and Engineering, Nonlinear Optimization

    L1 spline fits are a class of spline models that have shown advantages in approximating irregular and multiscale data. This paper investigates the knot placement problem of L1 spline fits under two scenarios. If the number of knots is given, we propose an augmented Lagrangian method to solve the bilevel L1 spline fit problem and … Read more

    Portfolio-wide Optimization of Pharmaceutical R&D Activities Using Mathematical Programming

  • Jon Dieringer
  • Chrysanthos E. Gounaris
  • Sal Garcia-Munoz
  • Steve Guntz
  • Nikolaos Lappas
  • Shankarraman Vaidyaraman
  • Shekhar Viswanath
  • Hua Wang
    • Categories Scheduling Tags

    The R&D management in any major research pharmaceutical company is constantly faced with the need to make complicated activity scheduling and resource allocation decisions, as they carry out scientific work to develop new therapeutic products. This paper describes how we develop a decision support tool that allows practitioners to determine portfolio-wide optimal schedules in a … Read more