E(χ2)-optimal mixed-level supersaturated designs

This paper introduces an optimality criterion for mixed-level supersaturated designs, called E(χ2), which covers E(s2) for two-level designs and ave(χ2) for symmetrical designs as two special cases. Some lower bounds of E(χ2) are obtained. Furthermore, it is shown that the E(χ2) criterion coincides with other existing criteria for nonregular mixed-level fractional factorial designs, which include minimum moment aberration, generalized minimum aberration, discrete uniformity and design efficiency. Several classes of E(χ2)-optimal mixed-level supersaturated designs from saturated orthogonal arrays are given.