Ioannis Chatzigiannakis Georgios Mylonas Sotiris E. Nikoletseas Modeling and Evaluation of the Effect of Obstacles on the Performance of Wireless Sensor Networks. 50-60 2006 conf/anss/2006 Annual Simulation Symposium http://doi.ieeecomputersociety.org/10.1109/ANSS.2006.26 db/conf/anss/anss2006.html#ChatzigiannakisMN06