energy sink
4.Abstract By setting up a network model of data aggregation and using a bit-hop metric to quantify energy costs in wireless sensor networks, we formally analyze the problem of area-based data aggregation and obtain that data aggregation will definitely be energy efficient when the relative difference between the average lengths of the two shortest paths, which are from source sensor nodes to the sink and to the aggregation node respectively, is not less than the ratio of data correlation to the number of source sensor nodes.
5.Abstract: In view of the complexity of air leakage form in comprehensive mechanized sublevel caving mining non-pillar compound mining field, a pressure energy testing to ventilation system adjacent to fully-mechanized sublevel caving mining working face is proceeded in Dongtan mine of Yanzhou in Shandong province, source and sink of air leakage are determined primarily, SF6 gas is released by using transient state method, the air speed of air leakage of every point and air leakage quantity in mining field and its distribution state can be determined by test and analysis.
