mixed-integer programming

Analysis of mixed integer programming formulations for single machine scheduling problems with sequence dependent setup times and release dates

  • Carlos R. V. Carvalho
  • Mauricio Cardoso de Souza
  • Thiago Henrique Nogueira
  • Martín Gómez Ravetti
    • Categories Scheduling Tags , , ,

    In this article, six different mixed integer programming (MIP) formulations are proposed and analyzed. These formulations are based on the knowledge of four different paradigms for single machine scheduling problems (SMSP) with sequence dependent setup times and release dates. Each formulation reflects a specific concept on how the variables and parameters are defined, requiring particular … Read more

    Tight MIP Formulations of the Power-Based Unit Commitment Problem

  • Claudio Gentile
  • Germán Morales-España
  • Andres Ramos
    • Categories (Mixed) Integer Linear Programming, Scheduling Tags , , , , ,

    This paper provides the convex hull description for the basic operation of slow- and quick-start units in power-based unit commitment (UC) problems. The basic operating constraints that are modeled for both types of units are: 1) generation limits and 2) minimum up and down times. Apart from this, the startup and shutdown processes are also … Read more

    A Tight MIP Formulation of the Unit Commitment Problem with Start-up and Shut-down Constraints

  • Claudio Gentile
  • Germán Morales-España
  • Andres Ramos
    • Categories (Mixed) Integer Linear Programming, Scheduling Tags , ,

    This paper provides the convex hull description for the following basic operating constraints of a single power generation unit in Unit Commitment (UC) problems: 1) generation limits, 2) startup and shutdown capabilities, and 3) minimum up and down times. Although the model does not consider some crucial constraints, such as ramping, the proposed constraints can … Read more

    Power-Capacity and Ramp-Capability Reserves for Wind Integration in Power-Based UC

  • Ross Baldick
  • Germán Morales-España
  • Javier García-González
  • Andres Ramos
    • Categories Applications - OR and Management Sciences, Robust Optimization, Stochastic Programming Tags , , , ,

    This paper proposes a power-based network-constrained unit commitment (UC) model as an alternative to the traditional deterministic UCs to deal with wind generation uncertainty. The formulation draws a clear distinction between power-capacity and ramp-capability reserves to deal with wind production uncertainty. These power and ramp requirements can be obtained from wind forecast information. The model … Read more

    On Global Optimization

  • Isaac Siwale
    • Categories (Mixed) Integer Nonlinear Programming, Global Optimization, Multi-Criteria Optimization Tags , , , ,

    This paper presents a relatively “unfettered” method for finding global optima to constrained nonlinear programs. The method reformulates the given program into a bi-objective mixed-integer program that is then solved for the Nash equilibrium. A numerical example (whose solution provides a new benchmark against which other algorithms may be assessed) is included to illustrate the … Read more

    n-step cycle inequalities: facets for continuous n-mixing set and strong cuts for multi-module capacitated lot-sizing problem

  • Manish Bansal
  • Kiavash Kianfar
    • Categories (Mixed) Integer Linear Programming, Cutting Plane Approaches, Production and Logistics Tags , , , , ,

    In this paper, we introduce a generalization of the continuous mixing set (which we refer to as the continuous n-mixing set). This set is closely related to the feasible set of the multi-module capacitated lot-sizing (MML) problem with(out) backlogging. We develop new classes of valid inequalities for this set, referred to as n’-step cycle inequalities, … Read more

    How important are branching decisions: fooling MIP solvers

  • Pierre Le Bodic
  • George L. Nemhauser
    • Categories (Mixed) Integer Linear Programming Tags , , , ,

    We show the importance of selecting good branching variables by exhibiting a family of instances for which an optimal solution is both trivial to find and provably optimal by a fixed-size branch-and-bound tree, but for which state-of-the-art Mixed Integer Programming solvers need an increasing amount of resources. The instances encode the edge-coloring problem on a … Read more

    Unit commitment with valve-point loading effect

  • Mikio Kubo
  • João Pedro Pedroso
  • Ana Viana
    • Categories Applications - OR and Management Sciences, Production and Logistics, Scheduling Tags , , ,

    Valve-point loading affects the input-output characteristics of generating units, bringing the fuel costs nonlinear and nonsmooth. This has been considered in the solution of load dispatch problems, but not in the planning phase of unit commitment. This paper presents a mathematical optimization model for the thermal unit commitment problem considering valve-point loading. The formulation is … Read more

    CBLIB 2014: A benchmark library for conic mixed-integer and continuous optimization

  • Henrik A. Friberg
    • Categories Integer Programming, Linear, Cone and Semidefinite Programming, Optimization Software Benchmark Tags , , , , ,

    The Conic Benchmark Library (CBLIB 2014) is a collection of more than a hundred conic optimization instances under a free and open license policy. It is the first extensive benchmark library for the advancing field of conic mixed-integer and continuous optimization, which is already supported by all major commercial solvers and spans a wide range … Read more

    Planning for Mining Operations with Time and Resource Constraints

  • Christina Burt
  • Peter J. Stuckey
  • Nir Lipovetzky
  • Adrian R. Pearce
    • Categories Production and Logistics, Scheduling, Transportation Tags , , ,

    We study a daily mine planning problem where, given a set of blocks we wish to mine, our task is to generate a mining sequence for the excavators such that blending resource constraints are met at various stages of the sequence. Such time-oriented resource constraints are not traditionally handled well by automated planners. On the … Read more