Stochastic Programming

Stochastic Dynamic Linear Programming: A Sequential Sampling Algorithm for Multistage Stochastic Linear Programming

  • Harsha Gangammanavar
  • Suvrajeet Sen
    • Categories Stochastic Programming Tags , , ,

    Multistage stochastic programming deals with operational and planning problems that involve a sequence of decisions over time while responding to realizations that are uncertain. Algorithms designed to address multistage stochastic linear programming (MSLP) problems often rely upon scenario trees to represent the underlying stochastic process. When this process exhibits stagewise independence, sampling-based techniques, particularly the … Read more

    Stochastic generalized gradient methods for training nonconvex nonsmooth neural networks

  • Vladimir I. Norkin
    • Categories Nonlinear Optimization, Nonsmooth Optimization, Stochastic Programming Tags , , , , ,

    The paper observes a similarity between the stochastic optimal control of discrete dynamical systems and the learning multilayer neural networks. It focuses on contemporary deep networks with nonconvex nonsmooth loss and activation functions. The machine learning problems are treated as nonconvex nonsmooth stochastic optimization problems. As a model of nonsmooth nonconvex dependences, the so-called generalized … Read more

    Nurse Staffing under Absenteeism: A Distributionally Robust Optimization Approach

  • Ruiwei Jiang
  • Minseok Ryu
    • Categories Applications - OR and Management Sciences, Robust Optimization, Stochastic Programming

    We study the nurse staffing problem under random nurse demand and absenteeism. While the demand uncertainty is exogenous (stemming from the random patient census), the absenteeism uncertainty is endogenous, i.e., the number of nurses who show up for work partially depends on the nurse staffing level. For the quality of care, many hospitals have developed … Read more

    Risk-Averse Optimal Control

  • Alois Pichler
  • Ruben Schlottter
    • Categories Dynamic Programming, Stochastic Programming Tags , ,

    In the context of multistage stochastic optimization, it is natural to consider nested risk measures, which originate by repeatedly composing risk measures, conditioned on realized observations. Starting from this discrete time setting, we extend the notion of nested risk measures to continuous time by adapting the risk levels in a time dependent manner. This time … Read more

    Substantiation of the Backpropagation Technique via the Hamilton-Pontryagin Formalism for Training Nonconvex Nonsmooth Neural Networks

  • Vladimir I. Norkin
    • Categories Convex and Nonsmooth Optimization, Nonlinear Optimization, Stochastic Programming Tags , , , , ,

    The paper observes the similarity between the stochastic optimal control of discrete dynamical systems and the training multilayer neural networks. It focuses on contemporary deep networks with nonconvex nonsmooth loss and activation functions. In the paper, the machine learning problems are treated as nonconvex nonsmooth stochastic optimization problems. As a model of nonsmooth nonconvex dependences, … Read more

    Generalized Gradients in Problems of Dynamic Optimization, Optimal Control, and Machine Learning

  • Vladimir I. Norkin
    • Categories Nonsmooth Optimization, Stochastic Programming Tags , , , , , , ,

    In this work, nonconvex nonsmooth problems of dynamic optimization, optimal control in discrete time (including feedback control), and machine learning are considered from a common point of view. An analogy is observed between tasks of controlling discrete dynamic systems and training multilayer neural networks with nonsmooth target function and connections. Methods for calculating generalized gradients … Read more

    Periodical Multistage Stochastic Programs

  • Lingquan Ding
  • Alexander Shapiro
    • Categories Stochastic Programming Tags , , , , ,

    In some applications the considered multistage stochastic programs have a periodical behavior. We show that in such cases it is possible to drastically reduce the number of stages by introducing a periodical analog of the so-called Bellman equations for discounted infinite horizon problems, used in Markov Decision Processes and Stochastic Optimal Control. Furthermore, we describe … Read more

    Penalized stochastic gradient methods for stochastic convex optimization with expectation constraints

  • Xiantao Xiao
    • Categories Stochastic Programming Tags , , , ,

    Stochastic gradient method and its variants are simple yet effective for minimizing an expectation function over a closed convex set. However, none of these methods are applicable to solve stochastic programs with expectation constraints, since the projection onto the feasible set is prohibitive. To deal with the expectation constrained stochastic convex optimization problems, we propose … Read more

    The risk-averse ultimate pit problem

  • Gianpiero Canessa
  • Bernardo K. Pagnoncelli
  • Eduardo Moreno
    • Categories 0-1 Programming, Stochastic Programming

    In this work, we consider a risk-averse ultimate pit problem where the grade of the mineral is uncertain. We propose a two-stage formulation of the problem and discuss which properties are desirable for a risk measure in this context. We show that the only risk measure that satisfies these properties is the entropic. We propose … Read more

    Wasserstein Distributionally Robust Optimization: Theory and Applications in Machine Learning

  • Daniel Kuhn
  • Peyman Mohajerin Esfahani
  • Viet Anh Nguyen
  • Soroosh Shafieezadeh-Abadeh
    • Categories Robust Optimization, Stochastic Programming

    Many decision problems in science, engineering and economics are affected by uncertain parameters whose distribution is only indirectly observable through samples. The goal of data-driven decision-making is to learn a decision from finitely many training samples that will perform well on unseen test samples. This learning task is difficult even if all training and test … Read more