We present a perfect formulation for a single generator in the unit commitment problem, inspired by the dynamic programming approach taken by Frangioni and Gentile. This generator can have characteristics such as ramping constraints, time-dependent start-up costs, and start-up/shut-down ramping. To develop this perfect formulation we extend the result of Balas on unions of polyhedra to present ...

We study multiobjective optimization problems arising from chemical process simulation. Interactive multiobjective optimization method NIMBUS, developed at the University of Jyväskylä, is combined with the BALAS process simulator, developed at the Technical Research Center of Finland, in order to provide a new interactive tool for designing chemical processes. Continuous interaction between the...

Schoute (1911) introduced the permutahedron on an n-element set N= { 1, . . . , n} as follows. With any permutation n of N we associate an incidence vector x(71) = (n(I), *.., n(n)) E IR”. The permutahedron is the polytope Perm(N) = conv{x(rr): rr is a permutation of N}. Independently, several authors (cf., e.g., Rado [4], Balas [l], Gaiha and Gupta [2], Young [6]) studied the permutahedron and...

Introdução: A alta ingestão de açucares, ácidos e grãos cereais processados, fez com que os índices cáries erosão dentárias aumentassem seus números. As balas, devido ao tempo elas demoram a ser completamente dissolvidas na boca, podem influênciar no aparecimento da cárie. Além disso, algumas balas também possuem em suas formulações um potencial erosivo. Objetivo: Esse artigo tem como objetivo ...