Donghoon Lee Vishnu Kumar Kaliappan Duckwon Chung Dugki Min An energy efficient dynamic routing scheme for clustered sensor network using a ubiquitous robot. 198-203 2008 RIVF http://dx.doi.org/10.1109/RIVF.2008.4586355 conf/rivf/2008 db/conf/rivf/rivf2008.html#LeeKCM08