1. Department of Industrial Engineering, University of Chile, Republica 701, Of. 31, Santiago, Chile. E-mail: ajimenez@dii.uchile.cl
2. Department of Computer Science, KAIST – Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Republic of Korea. E-mail: iko@kaist.ac.kr