Regular two-level fractional factorial designs are often used in industrial experiments as screening experiments. When some factors have levels which are hard or expensive to change, restrictions are often placed on the order in which runs can be performed, resulting in a split-plot factorial design. In these cases, the hard or expensive to change factors are applied to whole plots, whereas the...

Recent literature has proposed integrating observed noise variables into a factorial design structure as an alternative robust design strategy. Because noise factors are often difficult to control or randomize, observing their values may be useful. This research compares existing alternatives involving unreplicated fractional factorial designs and observable noise factors.

Multi-level factorial designs are useful in experiments but their aliasing structure are complex compare to two-level fractional factorial designs. A new framework is proposed to study the complex aliasing of those designs. Geometric aliasing is deened for factorial designs. It generalize of the aliasing relation of regular two level fractional fac-torial designs to all factorial designs. Based...

A Two-Level Fractional Factorial design was employed to develop and optimize the combination of demographic characteristics that has the greatest effect on the spread of HIV in the South African population. HIV prevalence (dependent variable) was found to be highly sensitive to changes in the mother’s age (15-55years) and level of education (Grades 0-13) (independent variables), using the 2006 ...

In this paper, we show that the projection of a regular orthogonal array of strength t onto more than t factors consists of replicates of either a fractional factorial or a full factorial design of strength t, depending on the number of factors retained in the projection.

1. In poultry investigations, the main interest is often to study the effects of many factors simultaneously. Two or three level factorial designs are the most commonly used for this type of investigation. However, it is often too costly to perform when number of factors increase. So a fractional factorial design, which is a subset or a fraction of a full factorial design, is an alternative. Th...

When it is impractical to perform the experimental runs of a fractional factorial design in a completely random order, restrictions on the randomization can be imposed. The resulting design is said to have a split-plot, or nested, error structure. Similarly to fractional factorials, fractional factorial split-plot designs can be ranked by using the aberration criterion.Techniques that generate ...

Minimum aberration designs are obtained for two types of mixed-level fractional factorial: (i) (s) × s factorial, and (ii) (s1) × (s2) × s factorial, where s is any prime or prime power, and r, r1, r2 and n are positive integers. Projective geometric tools are employed to find the wordlength pattern of a given design in terms of that of its complementary set. Many useful designs are found