of Dissertation Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy STRONG VALID INEQUALITIES FOR MIXED-INTEGER NONLINEAR PROGRAMS VIA DISJUNCTIVE PROGRAMMING AND LIFTING By Kwanghun Chung August 2010 Chair: Jean-Philippe. P. Richard Major: Industrial and Systems Engineering Mixed-Integer Nonlinear Progr...

Nonconvex mixed-integer nonlinear optimization problems frequently appear in practice and are typically extremely hard to solve. In this paper we discuss a class of primal heuristics that are based on a reformulation of the problem as a mathematical program with equilibrium constraints. We then use different regularization schemes for this class of problems and use an iterative solution procedu...

Optimizing scheduling is an effective way to improve the profit of refineries; it usually requires accurate models to describe the complex and nonlinear refining processes. However, conventional nonlinear models will result in a complex mixed integer nonlinear programming (MINLP) problem for scheduling. This paper presents a piecewise linear (PWL) modeling approach, which can describe global no...

In this paper, we study the problem of technical transient gas network optimization, which can be considered as a minimum cost flow problem with a nonlinear objective function and additional nonlinear constraints on the network arcs. Applying an implicit box scheme to the isothermal Euler equation, we derive a mixed integer nonlinear program. This is solved by means of a combination of (i) a no...

In this work we propose a simultaneous scheduling and control optimization formulation to address both optimal steady-state production and dynamic product transitions in continuous multiproduct tubular reactors. The simultaneous scheduling and control problem for continuous multiproduct tubular reactors is cast as a Mixed-Integer Dynamic Optimization (MIDO) problem. The dynamic behavior of the ...