Gary R. Kocis

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This paper presents an Equality Relaxation variant to the Outer-Approximation algorithm for solving mixed-integer nonlinear programming (MINLP) problems that arise in structural optimization of process flowsheets. The proposed algorithm has the important capability of being able to explicitly handle nonlinear equations within MINLP formulations that have(More)
This paper discusses an implementation of the Outer-Approximation/Equality-Relaxation algorithm for solving MINLP problems that arise in process systems engineering. The computer code DICOPT has been developed utilizing state-of-the-art optimization tools and a powerful modelling language. Computational experience in solving fifteen MINLP problems with(More)
The maritime oil tanker routing and scheduling problem is known to the literature since before 1950. In the presented problem, oil tankers transport crude oil from supply points to demand locations around the globe. The objective is to find ship routes, load sizes, as well as port arrival and departure times, in a way that minimizes transportation costs. We(More)
This paper shows that in structural flowsheet optimization problems that are formulated as mixed-integer nonlinear programming (MINLP) problems, modelling can have a great impact in the quality of solutions that are obtained, as well as on the computational efficiency. A modelling/decomposition strategy is proposed to exploit the special structure of(More)
This paper illustrates how operations research can be applied to large-scale maritime crude oil transportation. The more the industry strives to improve the efficiency of their supply chains the more complex and involved planning tasks become. Crude oil tanker routing and scheduling is a good example for a highly complex planning problem in the petroleum(More)
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