Article history: Received 12 July 2007 Received in revised form 10 March 2008 Accepted 12 March 2008 Available online 18 March 2008 MSC: primary 62K15 secondary 62K05

A supersaturated design is a design whose run size is not large enough for estimating all the main effects. The goodness of multi-level supersaturated designs can be judged by the generalized minimum aberration criterion proposed by Xu and Wu [Ann. Statist. 29 (2001) 1066–1077]. A new lower bound is derived and general construction methods are proposed for multi-level supersaturated designs. In...

We specify the optimal level of copyright protection for an individual producer and the society as a whole. For an individual producer, the optimal level is (i) no protection, (ii) the level under which the producer’s overall profit net of the development cost is zero, or (iii) full protection. The optimal level for the society, on the other hand, critically depends on the distribution of firms...