parametric integer programming deals with a family of integer programs that is defined by the same constraint matrix but where the right-hand sides are points of a given polyhedron. The question is whether all these i...
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parametric integer programming deals with a family of integer programs that is defined by the same constraint matrix but where the right-hand sides are points of a given polyhedron. The question is whether all these integer programs are feasible. Kannan showed that this can be checked in polynomial time if the number of variables in the integer programs is fixed and the polyhedron of right-hand sides has fixed affine dimension. In this paper, we extend this result by providing a polynomial algorithm for this problem under the only assumption that the number of variables in the integer programs is fixed. We apply this result to deduce a polynomial algorithm to compute the maximum gap between the optimum values of an integer program in fixed dimension and its linear programming relaxation, as the right-hand side is varying over all vectors for which the integer program is feasible.
A method is developed for carrying out parametric analysis on a mixed integer linear program (MILP) as either objective function coefficients or right-hand-side values of the constraints are varied continuously. The m...
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A method is developed for carrying out parametric analysis on a mixed integer linear program (MILP) as either objective function coefficients or right-hand-side values of the constraints are varied continuously. The method involves solving MILPs at point values of the parameters of variation and joining the results by LP parametric analysis.
A branch-and-bound algorithm to solve 0–1 parametric mixed integer linear programming problems has been developed. The present algorithm is an extension of the branch-and-bound algorithm for parametric analysis on pu...
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A branch-and-bound algorithm to solve 0–1 parametric mixed integer linear programming problems has been developed. The present algorithm is an extension of the branch-and-bound algorithm for parametric analysis on pure integerprogramming. The characteristic of the present method is that optimal solutions for all values of the parameter can be obtained.
We address the problem of finding the optimal bidding strategy of an energy producer that participates in a single-period day-ahead electricity market, assuming full knowledge of the market's parameters. The probl...
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We address the problem of finding the optimal bidding strategy of an energy producer that participates in a single-period day-ahead electricity market, assuming full knowledge of the market's parameters. The problem is formulated as a mixed integer bilevel optimization model, with the producer maximizing his individual profit, at the upper level, and an independent system operator clearing the market at the minimum total system bid-cost, at the lower level. The model utilizes discrete variables to represent the commitment of the production units, which prohibits the application of typical methodologies for finding its optimal solution, such as the substitution of the lower level problem by its first-order KKT optimality conditions. We develop an exact algorithm for the solution of the problem that utilizes important findings from the theory of parametric integer programming, and we report experimental results demonstrating its efficiency on random problem instances. We conclude with a discussion on several computational issues pertaining to the behaviour of this algorithm, and an outline of how the theory developed in the present work can be modified to fit alternative market designs.
In contrast to methods of parametric linear programming which were developed soon after the invention of the simplex algorithm and are easily included as an extension of that method, techniques for parametric analysis...
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For the two-stage quadratic stochastic program where the second-stage problem is a general mixed-integer quadratic program with a random linear term in the objective function and random right-hand sides in constraints...
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For the two-stage quadratic stochastic program where the second-stage problem is a general mixed-integer quadratic program with a random linear term in the objective function and random right-hand sides in constraints, we study continuity properties of the second-stage optimal value as a function of both the first-stage policy and the random parameter vector. We also present sufficient conditions for lower or upper semicontinuity, continuity, and Lipschitz continuity of the second-stage problem's optimal value function and the upper semicontinuity of the optimal solution set mapping with respect to the first-stage variables and/or the random parameter vector. These results then enable us to establish conclusions on the stability of optimal value and optimal solutions when the underlying probability distribution is perturbed with respect to the weak convergence of probability measures.
In order to derive continuity and stability of two-stage stochastic programs with mixed-integer recourse when all coefficients in the second-stage problem are random, we first investigate the quantitative continuity o...
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In order to derive continuity and stability of two-stage stochastic programs with mixed-integer recourse when all coefficients in the second-stage problem are random, we first investigate the quantitative continuity of the objective function of the corresponding continuous recourse problem with random recourse matrices. Then by extending derived results to the mixed-integer recourse case, the perturbation estimate and the piece-wise lower semi-continuity of the objective function are proved. Under the framework of weak convergence for probability measure, the epi-continuity and joint continuity of the objective function are established. All these results help us to prove a qualitative stability result. The obtained results extend current results to the mixed-integer recourse with random recourse matrices which have finitely many atoms.
In this paper, we consider the counting function EP(y)=|Py boolean AND Znx|\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepac...
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In this paper, we consider the counting function EP(y)=|Py boolean AND Znx|\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\,\mathrm{{{\,\mathrm{\mathcal {E}}\,}}_{{{\,\mathrm{\mathcal {P}}\,}}}}\,}}(y) = |{{\,\mathrm{\mathcal {P}}\,}}_{y} \cap {{\,\mathrm{\mathbb {Z}}\,}}<^>{n_x}|$$\end{document} for a parametric polyhedron Py={x is an element of Rnx:Ax <= b+By}\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\,\mathrm{\mathcal {P}}\,}}_{y} = \{ x \in {{\,\mathrm{\mathbb {R}}\,}}<^>{n_x} :A x \le b + B y\}$$\end{document}, where y is an element of Rny\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$y \in {{\,\mathrm{\mathbb {R}}\,}}<^>{n_y}$$\end{document}. We give a new representation of EP(y)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\,\mathrm{{{\,\mathrm{\mathcal {E}}\,}}_{{{\,\mathrm{\mathcal {P}}\,}}}}\,}}(y)$$\end{document}, called a piece-wise step-polynomial with periodic coefficients, which is a generalization of piece-wise step-polynomials and integer/rational Ehrhart's quasi-polynomials. It gives the fastest way to calculate EP(y)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{
作者:
VOROS, JUNIV PECS
FAC BUSINESS & ECONRAKOCZI 80H-7622 PECSHUNGARY
In this paper the multi-level dynamic lot sizing problem is investigated in which setup costs are parameters and the range within which setup costs can vary without changing the optimal solution is determined. The com...
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In this paper the multi-level dynamic lot sizing problem is investigated in which setup costs are parameters and the range within which setup costs can vary without changing the optimal solution is determined. The computations are significantly shortened by the fact that the holding cost function is convex in the number of setups. The topic also raises the problem of convexity of a multi-variable integer function and the search for the neighbouring integer points of the minimum.
For two-stage stochastic programs with integrality constraints in the second stage, we study continuity properties of the expected recourse as a function both of the first-stage policy and the integrating probability ...
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For two-stage stochastic programs with integrality constraints in the second stage, we study continuity properties of the expected recourse as a function both of the first-stage policy and the integrating probability measure. Sufficient conditions for lower semicontinuity, continuity and Lipschitz continuity with respect to the first-stage policy are presented. Furthermore, joint continuity in the policy and the probability measure is established. This leads to conclusions on the stability of optimal values and optimal solutions to the two-stage stochastic program when subjecting the underlying probability measure to perturbations.
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