ABSTRACT
There is a variety of general purpose unconstrained optimization methods that can be used to estimate unknown parameters. These methods are broadly classified into two categories: direct search methods and gradient methods (Edgar and Himmelblau, 1988; Gill et al. 1981; Kowalik and Osborne, 1968; Sargent, 1980; Reklaitis, 1983; Scales, 1985).
