M. Roma ́n, C. Hess, R. Cerqueira, A. Ranganathan, R. H. Campbell, and K. Nahrstedt, BA middleware infrastructur for active spaces,[ IEEE Pervasive Comput., vol. 1, no. 4, pp. 74–83, Oct.–Dec. 2002. N. Lewis, Toward cost-effective solar energy use,[ Science, vol. 315, no. 5813, pp. 798–801, 2007.