Resumen
This paper introduces an optimality criterion for mixed-level supersaturated designs, called E(@g^2), which covers E(s^2) for two-level designs and ave(@g^2) for symmetrical designs as two special cases. Some lower bounds of E(@g^2) are obtained. Furthermore, it is shown that the E(@g^2) 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(@g^2)-optimal mixed-level supersaturated designs from saturated orthogonal arrays are given.

Resumen
In this paper we use the empirical likelihood method to construct confidence interval for truncation parameter in random truncation model. The empirical log-likelihood ratio is derived and its asymptotic distribution is shown to be a weighted chi-square. Simulation studies are used to compare the confidence intervals based on empirical likelihood and those based on normal approximation. It is found that the empirical likelihood method provides improved confidence interval.