Comparison of our method with 11 existing methods based on three performance indices. This figures shows the comparison results of our methods with 11 existing methods using (a) the performance index 1, (b) the performance index 2, and (c) the performance index 3. Note that T stands for our method, A1 for Banerjee and Zhang' s method, A2 for Chang et al.'s method, A3 for Chen et al.'s method, A4 for Datta and Zhao's method, A5 for Elati et al.'s method, A6 for He et al.'s method, A7 for Nagamne et al.'s method, A8 for Tsai et al.'s method, A9 for Wang's method, A10 for Yang et al.'s method, and A11 for Yu et al.'s method.