Fig. 9

The variance of the MSE achieved by the three schemes under the constraints of ε = 0.01 and ε = 0.1. y-axis represents the MSE; x-axis represents the number of iterations. There are two subgraphs in the figure. The upper one represents the MSE achieved by the MSED, MHED, and SPSD under the MSE constraint of ε = 0.01; the bottom one represents the MSE achieved by the MSED, MHED, and SPSD under the MSE constraint of ε = 0.1. The black solid line represents MSED; the green line represents MHED; the red dotted line represents SPSD