Efficient clustering techniques to optimize the system lifetime in Wireless Sensor Network - Raju Dutta, A.; Sajal Saha, B.; Mukhopadhyay, C. Asish K. (IEEE-International Conference On Advances In Engineering, Science And Management (ICAESM -2012), Advances in Engineering, Science and Management (ICAESM), 2012 International Conference on, 2012)