Xiaofeng Han Xiang Cao Errol L. Lloyd Chien-Chung Shen Deploying Directional Sensor Networks with Guaranteed Connectivity and Coverage. 153-160 2008 SECON http://dx.doi.org/10.1109/SAHCN.2008.28 conf/secon/2008 db/conf/secon/secon2008.html#HanCLS08