Efficient Solution of Maximum-Entropy Sampling Problems

We consider a new approach for the maximum-entropy sampling problem (MESP) that is based on bounds obtained by maximizing a function of the form ldet M(x) over linear constraints, where M(x)is linear in the n-vector x. These bounds can be computed very efficiently and are superior to all previously known bounds for MESP on most … Read more

Location and Allocation of Service Units on a Congested Network with Time Varying Demand Rates

The service system design problem arises in the design of telecommunication networks, refuse collection and disposal networks in public sector, transportation planning, and location of emergency medical facilities. The problem seeks to locate service facilities, determine their capacities and assign users to those facilities under time varying demand conditions. The objective is to minimize total … Read more

Optimal Response to Epidemics and Cyber Attacks in Networks

This paper introduces novel formulations for optimally responding to epidemics and cyber attacks in networks. In our models, at a given time period, network nodes (e.g., users or computing resources) are associated with probabilities of being infected, and each network edge is associated with some probability of propagating the infection. A decision maker would like … Read more

A new, solvable, primal relaxation for convex nonlinear integer programming problems

The paper describes a new primal relaxation (PR) for computing bounds on nonlinear integer programming (NLIP) problems. It is a natural extension to NLIP problems of the geometric interpretation of Lagrangean relaxation presented by Geoffrion (1974) for linear problems, and it is based on the same assumption that some constraints are complicating and are treated … Read more

Combining QCR and CHR for Convex Quadratic MINLP Problems with Linear Constraints

The convex hull relaxation (CHR) method (Albornoz 1998, Ahlatçıoğlu 2007, Ahlatçıoğlu and Guignard 2010) provides lower bounds and feasible solutions (thus upper bounds) on convex 0-1 nonlinear programming problems with linear constraints. In the quadratic case, these bounds may often be improved by a preprocessing step that adds to the quadratic objective function terms which … Read more

On the Chvtal-Gomory Closure of a Compact Convex Set

In this paper, we show that the Chatal-Gomory closure of a compact convex set is a rational polytope. This resolves an open question discussed in Schrijver 1980 and generalizes the same result for the case of rational polytopes (Schrijver 1980), rational ellipsoids (Dey and Vielma 2010) and strictly convex sets (Dadush et. al 2010). In … Read more

Exact Penalty Functions for Nonlinear Integer Programming Problems

In this work, we study exact continuous reformulations of nonlinear integer programming problems. To this aim, we preliminarily state conditions to guarantee the equivalence between pairs of general nonlinear problems. Then, we prove that optimal solutions of a nonlinear integer programming problem can be obtained by using various exact penalty formulations of the original problem … Read more