An automatic video content summarization system that is able to create personalized multimedia summary based on the user-specified theme. The system includes a pressurized fluid source. The system is particularly relevant for depressurising high pressure natural gas pipelines in an energy efficient manner whilst making possible net power generation. Other embodiments may be described and claimed. The occurrence of faileddropped transmissions due to buffer overflows, excessive retransmission attempts, and unintended collisions are modeled as well.