All students, staff and visitors are welcome. The talk will be followed by snacks and drinks.
New three-level designs for screening in the presence of second-order terms
Screening is the first stage of many industrial experiments and is used to determine efficiently and effectively a small number of potential factors among a large number of factors which may affect a particular response. In a recent paper, Jones and Nachtsheim (2011b) have given a class of three-level designs for screening in the presence of second order effects using a variant of the coordinate exchange algorithm as it was given by Meyer and Nachtsheim (1995). Xiao et al. (2012) have used conference matrices to construct definitive screening designs with good properties. In this talk, we propose a method for the construction of efficient three-level screening designs based on weighing matrices and their complete foldover. This method can be considered as a generalisation of the method proposed by Xiao et al. (2012). Many new orthogonal three-level screening designs are constructed and their properties are explored. These designs are highly D-efficient and provide uncorrelated estimates of main effects that are unbiased by any second order effect. Our approach is relatively straightforward and no computer search is needed since our designs are constructed using known weighing matrices.
Dr Stelios Georgiou