Experimental Design and Simulation in Unloading Ships by Helicopter

Should military cargo be unloaded from ships by lighter or by helicopter? To evaluate various unloading vehicles, a simulation was constructed around a linear programming algorithm. It represented helicopters, lighters, trucks, and the maintenance, stevedoring, and supply units required on shore to support them. The type of helicopter performing best in the simulation was sensitive to the estimate of its productivity. A field test to determine this figure was planned, and data from the simulation was used to determine what mathematical characteristics the test design should have. As finally developed, the test selected was a three-quarter replication of an unblocked, fractional-factorial design employing an analysis of covariance. The design had to make provision for sudden changes arising during the course of test execution, as it was to be carried out in Vietnam.