“…Since then, exact and approximate solution methods have been developed for a variety of batch processor problems. These include models where the processing time of the batch is determined by the longest processing time among the jobs in the batch (e.g., Glassey and Weng 1991, Ahmadi et al 1992, Lee et al 1992, Chandru et al 1993a, Avramidis et al 1998, Lee and Uzsoy 1999 and those that schedule multiple incompatible job families (e.g., Chandru et al 1993b, Uzsoy 1995, Webster and Baker 1995, Mehta and Uzsoy 1998, Azizoglu and Webster 2001, Sung et al 2002, Wang and Uzsoy 2002, Monch et al 2004, Perez et al 2005 where jobs of different families cannot be batched together. Note that problems with a single job family fit equally well into both of the above categories.…”