Relaxing nonconvex quadratic functions by multiple adaptive diagonal perturbations

The current bottleneck of globally solving mixed-integer (nonconvex) quadratically constrained problem (MIQCP) is still to construct strong but computationally cheap convex relaxations, especially when dense quadratic functions are present. We pro- pose a cutting surface procedure based on multiple diagonal perturbations to derive strong convex quadratic relaxations for nonconvex quadratic problem with separable constraints. Our … Read more

A globally convergent trust-region algorithm for unconstrained derivative-free optimization

In this work we explicit a derivative-free trust-region algorithm for unconstrained optimization based on the paper (Computational Optimization and Applications 53: 527-555, 2012) proposed by Powell. The objective function is approximated by quadratic models obtained by polynomial interpolation. The number of points of the interpolation set is fixed. In each iteration only one interpolation point … Read more

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

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

An Improved Stochastic Optimization Model for Water Supply Pumping Systems in Urban Networks

This study investigates a pump scheduling problem for the collection, transfer and storage of water in water supply systems in urban networks. The objective of this study is to determine a method to minimize the electricity costs associated with pumping operations. To address the dynamic and random nature of water demand, we propose a two-stage … Read more

A Fast Active Set Block Coordinate Descent Algorithm for l1-regularized least squares

The problem of finding sparse solutions to underdetermined systems of linear equations arises in several real-world problems (e.g. signal and image processing, compressive sensing, statistical inference). A standard tool for dealing with sparse recovery is the l1-regularized least-squares approach that has been recently attracting the attention of many researchers. In this paper, we describe an … Read more

Derivative-free Methods for Mixed-Integer Constrained Optimization Problems

Methods which do not use any derivative information are becoming popular among researchers, since they allow to solve many real-world engineering problems. Such problems are frequently characterized by the presence of discrete variables which can further complicate the optimization process. In this paper, we propose derivative-free algorithms for solving continuously differentiable Mixed Integer NonLinear Programming … Read more

Semidefinite Programming Reformulation of Completely Positive Programs: Range Estimation and Best-Worst Choice Modeling

We show that the worst case moment bound on the expected optimal value of a mixed integer linear program with a random objective c is closely related to the complexity of characterizing the convex hull of the points CH{(1 x) (1 x)’: x \in X} where X is the feasible region. In fact, we can … Read more

Choice Based Revenue Management for Parallel Flights

This paper describes a revenue management project with a major airline that operates in a fiercely competitive market involving two major hubs and having more than 30 parallel daily flights. The market has a number of unusual characteristics including (1) almost half of customers choose not to purchase the tickets after booking; (2) about half … Read more

On Auction Models of Conflict with Network Applications

We consider several models of complex systems with active elements and show that the auction mechanism appears very natural in attaining proper equilibrium states, even in comparison with game theory ones. In particular, network equilibria are treated as implementation of the auction principle. An additional example of resource allocation in wireless communication networks is also … Read more

A search for quantum coin-flipping protocols using optimization techniques

Coin-flipping is a cryptographic task in which two physically separated, mistrustful parties wish to generate a fair coin-flip by communicating with each other. Chailloux and Kerenidis (2009) designed quantum protocols that guarantee coin-flips with near optimal bias away from uniform, even when one party deviates arbitrarily from the protocol. The probability of any outcome in … Read more