Research Article

Adaptive Linear and Normalized Combination of Radial Basis Function Networks for Function Approximation and Regression

Table 3

Results of function approximation experiments in terms of mean-squared error (MSE), normalized correlation coefficient (NCC), and computation time consumption (CTC in ms).

Function name Evaluation RBFN SA WA ALNC

Zigzag MSE 0.0295 0.0735 0.0062 0.0164 0.0007 0.0049 0.0004 0.0011
NCC (%) 96.3055 9.6683 99.4763 9.3546 99.9250 6.3702 99.9571 4.2214
CTC (ms) 7.42 1.89 8.84 0.92 7.28 0.95

Rhythm MSE 0.0029 0.0010 0.0024 0.0013 0.0023 0.0012 0.0020 0.0009
NCC (%) 87.5134 5.0192 89.7075 3.2103 90.1384 2.8523 91.5593 1.8064
CTC (ms) 8.71 1.12 9.33 1.74 8.54 1.03

SinCos MSE 0.0634 0.2023 0.0055 0.0047 0.0000 0.0002 0.0000 0.0002
NCC (%) 97.7722 7.2694 99.9010 5.3231 100.0000 2.0012 100.0000 2.0012
CTC (ms) 9.01 1.24 9.24 1.01 8.52 1.36

ExpSin MSE 2.6070 5.9641 0.5745 0.2563 0.2246 0.1094 0.1793 0.0521
NCC (%) 98.9156 2.5046 99.7826 1.3005 99.9097 0.7421 99.9992 0.5096
CTC (ms) 8.42 1.88 9.12 3.65 9.07 2.09

3-D Mexican Hat MSE 0.0056 0.0092 0.0016 0.0022 0.0001 0.0003 0.0001 0.0003
NCC (%) 96.7638 5.4163 99.2510 2.3316 99.9973 0.05433 99.9992 0.0097
CTC (ms) 12.67 1.04 13.69 1.06 11.15 0.98

Gabor MSE 0.0526 0.0591 0.0284 0.0087 0.0044 0.0027 0.0030 0.0015
NCC (%) 85.9035 19.5016 94.5788 12.0816 99.1086 7.3341 99.4828 4.2035
CTC (ms) 12.41 1.35 12.97 1.39 11.79 1.19

SwingCos MSE 0.6108 0.2585 0.4614 0.2448 0.3663 0.1802 0.2018 0.0097
NCC (%) 79.6648 9.7284 86.2856 7.0205 89.2254 6.6522 94.3319 4.3316
CTC (ms) 11.38 0.74 13.03 0.89 11.65 0.81

Exponential MSE 0.0016 0.0022 0.0007 0.0003 0.0004 0.0001 0.0001 0.0001
NCC (%) 96.3979 5.2557 98.5697 3.4681 99.2090 1.0506 99.7315 0.6233
CTC (ms) 12.46 1.52 13.18 2.13 11.53 1.08