A note on polynomial solvability of the CDT problem
We describe a simple polynomial-time algorithm for the CDT problems that relies on a construction of Barvinok. CitationColumbia UniversityArticleDownload View PDF
Worst-Case Performance Analysis of Some Approximation Algorithms for Minimizing Makespan and Flow-Time
In 1976, Coffman and Sethi conjectured that a natural extension of LPT list scheduling to the bicriteria scheduling problem of minimizing makespan over flowtime optimal schedules, called LD algorithm, has a simple worst-case performance bound: (5m-2)/(4m-1) , where m is the number of machines. We study structure of potential minimal counterexamples to this conjecture and … Read more
Preconditioning issues in the numerical solution of nonlinear equations and nonlinear least squares
Second order methods for optimization call for the solution of sequences of linear systems. In this survey we will discuss several issues related to the preconditioning of such sequences. Covered topics include both techniques for building updates of factorized preconditioners and quasi-Newton approaches. Sequences of unsymmetric linear systems arising in Newton- Krylov methods will be … Read more
An Improvised Approach to Robustness in Linear Optimization
We treat uncertain linear programming problems by utilizing the notion of weighted analytic centers and notions from the area of multi-criteria decision making. In addition to many practical advantages, due to the flexibility of our approach, we are able to prove that the robust optimal solutions generated by our algorithms are at least as desirable … Read more
Multiple-choice Vector Bin Packing: Arc-flow Formulation with Graph Compression
The vector bin packing problem (VBP) is a generalization of bin packing with multiple constraints. In this problem we are required to pack items, represented by p-dimensional vectors, into as few bins as possible. The multiple-choice vector bin packing (MVBP) is a variant of the VBP in which bins have several types and items have … Read more
A First Course in Linear Optimization, version 3.0
This is the “front matter” of a new open-source book on Linear Optimization. The book and associated Matlab/AMPL/Mathematica programs are freely available from: https://sites.google.com/site/jonleewebpage/home/publications/#book CitationJon Lee, “A First Course in Linear Optimization”, Third Edition, Reex Press, 2013-2017.ArticleDownload View PDF
The inexact projected gradient method for quasiconvex vector optimization problems
Vector optimization problems are a generalization of multiobjective optimization in which the preference order is related to an arbitrary closed and convex cone, rather than the nonnegative octant. Due to its real life applications, it is important to have practical solution approaches for computing. In this work, we consider the inexact projected gradient-like method for … Read more
A Relaxed-Projection Splitting Algorithm for Variational Inequalities in Hilbert Spaces
We introduce a relaxed-projection splitting algorithm for solving variational inequalities in Hilbert spaces for the sum of nonsmooth maximal monotone operators, where the feasible set is defined by a nonlinear and nonsmooth continuous convex function inequality. In our scheme, the orthogonal projections onto the feasible set are replaced by projections onto separating hyperplanes. Furthermore, each … Read more
Lagrangean Decomposition for Mean-Variance Combinatorial Optimization
We address robust versions of combinatorial optimization problems, focusing on the uncorrelated ellipsoidal uncertainty case, which corresponds to so-called mean-variance optimization. We present a branch and bound-algorithm for such problems that uses lower bounds obtained from Lagrangean decomposition. This approach allows to separate the uncertainty aspect in the objective function from the combinatorial structure of … Read more
An inexact block-decomposition method for extra large-scale conic semidefinite programming
In this paper, we present an inexact block-decomposition (BD) first-order method for solving standard form conic semidefinite programming (SDP) which avoids computations of exact projections onto the manifold defined by the affine constraints and, as a result, is able to handle extra large SDP instances. The method is based on a two-block reformulation of the … Read more