Month: October 2018

Endogenous Price Zones and Investment Incentives in Electricity Markets: An Application of Multilevel Optimization with Graph Partitioning

  • Mirjam Ambrosius
  • Veronika Grimm
  • Thomas Kleinert
  • Frauke Liers
  • Martin Schmidt
  • Gregor Zöttl
    • Categories (Mixed) Integer Nonlinear Programming, Applications - OR and Management Sciences, Global Optimization Tags , , , ,

    In the course of the energy transition, load and supply centers are growing apart in electricity markets worldwide, rendering regional price signals even more important to provide adequate locational investment incentives. This paper focuses on electricity markets that operate under a zonal pricing market design. For a fixed number of zones, we endogenously derive the … Read more

    Dynamic Courier Routing for a Food Delivery Service

  • Mark Karwan
  • Chase Murray
  • Zachary Steever
    • Categories (Mixed) Integer Linear Programming, Applications - OR and Management Sciences, Transportation

    Services like Grubhub and UberEats have revolutionized the way that diners can find and order from restaurants. The standard business model for such services, however, allows diners to order from only one restaurant at a time. Inspired by a food delivery service in the southeastern United States, this paper proposes the framework for a more … Read more

    Scalable Branching on Dual Decomposition of Stochastic Mixed-Integer Programming Problems

  • Brian Dandurand
  • Kibaek Kim
    • Categories (Mixed) Integer Linear Programming, Parallel Algorithms, Stochastic Programming

    We present a scalable branching method for the dual decomposition of stochastic mixed-integer programming. Our new branching method is based on the branching method proposed by Caro e and Schultz that creates branching disjunctions on first-stage variables only. We propose improvements to the process for creating branching disjunctions, including 1) branching on the optimal solutions … Read more

    A non-monotone Inexact Restoration approach for minimization with orthogonality constraints

  • Fermín S. V. Bazán
  • Juliano B. Francisco
  • Douglas S. Gonçalves
  • Lila L. T. Paredes
    • Categories Nonlinear Optimization

    In this work we consider the problem of minimizing a differentiable functional restricted to the set of $n\times p$ matrices with orthonormal columns. This problem appears in several fields such as statistics, signal processing, global positioning system, machine learning, physics, chemistry and others. We present an algorithm based on a recent non-monotone variation of the … Read more

    Resilient layout, design and operation of energy-efficient water distribution networks for high-rise buildings using MINLP

  • Lena C. Altherr
  • Marc E. Pfetsch
  • Andreas Schmitt
  • Philipp Leise
    • Categories (Mixed) Integer Nonlinear Programming, Mechanical Engineering, Robust Optimization Tags , , , , , , ,

    Water supply of high-rise buildings requires pump systems to ensure pressure requirements. The design goal of these systems are energy and cost efficiency, both in terms of fixed cost as well as during operation. In this paper, cost optimal decentralized and tree-shaped water distribution networks are computed, where placements of pumps at different locations in … Read more

    A Subsampling Line-Search Method with Second-Order Results

  • Elhoucine Bergou
  • Youssef Diouane
  • Vyacheslav Kungurtsev
  • Clément W. Royer
  • V. Kunc
    • Categories Nonlinear Optimization, Unconstrained Optimization Tags , , , ,

    In many contemporary optimization problems such as those arising in machine learning, it can be computationally challenging or even infeasible to evaluate an entire function or its derivatives. This motivates the use of stochastic algorithms that sample problem data, which can jeopardize the guarantees obtained through classical globalization techniques in optimization such as a trust … Read more

    Non-monotone Inexact Restoration Method for nonlinear programming

  • Fermín S. V. Bazán
  • Juliano B. Francisco
  • Douglas S. Gonçalves
  • Lila L. T. Paredes
    • Categories Constrained Nonlinear Optimization

    This paper deals with a new variant of the Inexact Restoration Method of Fischer and Friedlander (COAP, 46, pp. 333-346, 2010). We propose an algorithm that replaces the monotone line-search performed in the tangent phase (with regard to the penalty function) by a non-monotone one. Con- vergence to feasible points satisfying the approximate gradient projection … Read more

    Learning a Mixture of Gaussians via Mixed Integer Optimization

  • Hari Bandi
  • Dimitris Bertsimas
  • Rahul Mazumder
    • Categories 0-1 Programming, Applications - OR and Management Sciences, Statistics Tags ,

    We consider the problem of estimating the parameters of a multivariate Gaussian mixture model (GMM) given access to $n$ samples $\x_1,\x_2,\ldots ,\x_n \in\mathbb{R}^d$ that are believed to have come from a mixture of multiple subpopulations. State-of-the-art algorithms used to recover these parameters use heuristics to either maximize the log-likelihood of the sample or try to … Read more

    Exploiting Low-Rank Structure in Semidefinite Programming by Approximate Operator Splitting

  • Joaquim Dias Garcia
  • Mario Souto
  • Alvaro Viega
    • Categories Convex Optimization, Optimization Software and Modeling Systems, Semi-definite Programming Tags , , , , ,

    In contrast with many other convex optimization classes, state-of-the-art semidefinite programming solvers are yet unable to efficiently solve large scale instances. This work aims to reduce this scalability gap by proposing a novel proximal algorithm for solving general semidefinite programming problems. The proposed methodology, based on the primal-dual hybrid gradient method, allows the presence of … Read more

    Assessing the Cost of the Hazard-Decision Simplification in Multistage Stochastic Hydrothermal Scheduling

  • Andre Lawson
  • Alexandre Street
  • Davi Valladão
  • Alexandre Velloso
    • Categories Control Applications, Dynamic Programming, Stochastic Programming Tags , , ,

    Hydropower is one of the world’s primary renewable energy sources whose usage has profound economic, environmental, and social impacts. We focus on the dispatch of generating units and the storage policy of hydro resources. In this context, an accurate assessment of the water opportunity-cost is cru- cial for driving the sustainable use of this scarce … Read more