Page 2 Lecture Notes in Computer Science 2865 Edited by G. Goos ...

206 S. PatilAvg. Aggregate Energy Consumption (in Joules)98765432T = 1T = 3T = 5T = 7T = 10T = 5011 2 3 4 5 6 7Depth of Searching (Number of hops)Fig. 1. Avg. Aggregate Energy Consumption for Iterative-Deepening Searchthe average aggregate bandwidth for d = 7 (i.e. rule 7 or classical flooding) isthe same, regardless of tt T. Since the inter-iteration interval, T is consideredonly between iterations, it does not affect IDEA-Rule R 7 = {7}, which hasonly a single iteration. Next, notice that as the number of hops for iteration,d, increases, the energy consumption of IDEA-Rule R d increases as well. Thelarger d is, the more likely the rule will waste bandwidth by sending the queryout to too many nodes i.e sending the query out to more nodes than necessary.Sending the query out to more nodes than necessary will generate more energyconsumption for forwarding the query, and transferring response messages backto the source. Hence, as d increases, bandwidth consumption increases as well,giving IDEA-Rule R 7 or classical flooding gives the worst energy consumptionperformance.Now, notice that as the inter-iteration interval, T, decreases, energy consumptionper query usage increases. If T is small, then it is highly possible that sourcewill assume that the query was not satisfied, leading to the overshooting effectas described earlier. For example, say T = 10 and d = 6, if a query Q can besatisfied at depth 6, but more time than T is required before certain number ofresults arrive at the client, then the client will only wait for T seconds, determinethat the query is not satisfied, and initiate the next iteration at depth 7. In thiscase, the source overshoots the goal. The smaller T is, the more often the sourcewill overshoot; hence, energy consumption usage increases as T decreases.T-IDEA decreases the number of nodes which would take part in the queryprocessing operation based on the local decisions and tokens created by eachnode. This helps in increasing the aggregate capacity of the network, sincesome nodes are not involved the energy consuming query processing process.