Nam et al. minimize energy wasting in wireless sensor network using simultaneous human activity pattern and Hierarchical Hidden Markov Model (HHMM) . Activity context model is constructed by analyzing the simultaneous activity patterns using Incrementally Simultaneous Method (ISM) and representing the simultaneous activity patterns using Allen’s temporal relation logic. The result shows that weekly saving energy average and rate are 327.69kW and 26% respectively.
 Nam, Yunyoung, Seungmin Rho, and Bok-gi Lee. ‘Intelligent Context-Aware Energy Management Using the Incremental Simultaneous Method in Future Wireless Sensor Networks and Computing Systems’. EURASIP Journal on Wireless Communications and Networking 2013, no. 1 (1 December 2013): 1–11. doi:10.1186/1687-1499-2013-10.