Two optimization techniques as used in a general four compartment first-order system

Life is a continuously changing phenomenon, and the capacity to observe time-dependent processes by nondestructive means (for example, by tracer techniques) provides functional information which cannot be otherwise obtained. The present study deals with the identification of exchange parameters for a general four compartment model in which the tracer in every compartment can exchange with every other compartment. The method of solution is based on two optimization techniques, namely: the Alienor technique and the Gabriel technique. These techniques reduce different unknowns involved in the problem to a single variable θ, with the help of Archimedesʹ spiral, thus leading to the global minimum of a functional of single variable θ. Results are compared with those obtained by generalized least squares method in terms of accuracy and computational time.