Table 6:
Model parameters, evaluation results, and WAIC metrics for 6 variance models (Table 1) of each task on our dataset. As shown, although there is no clear winner, the quadratic-variance model (Model #4 in Table 1) performed the best (or second-best) in three tasks, after taking into account the complexity of the model (i.e., the number of parameters).
Conditions | Variance Models | c | d | e | R 2 | RMSE [SD] | AIC | WAIC |
---|---|---|---|---|---|---|---|---|
Straight tunnel | σ2 = c | 0.979 [0.344, 1.627] | N/A | N/A | 0 | 767.0 [655.0] | 370.05 | 368.76 |
σ2 = (c · ID)2 | 0.054 [0.051, 0.056] | N/A | N/A | 0.966 | 148.2 [178.0] | 329.4 | 329.68 | |
σ2 = c + d · ID | −0.899 [−1.275, −0.519] | 0.115 [0.095, 0.136] | N/A | 0.948 | 239.0 [138.7] | 338.09 | 334.64 | |
σ 2 = c + d · ID 2 | 0.052 [−0.126, 0.229] | 0.003 [0.002, 0.003] | N/A | 0.968 | 163.3 [139.0] | 332.06 | 330.12 | |
σ2 = (c + d · ID)2 | 0.068 [−0.11,0.24] | 0.051 [0.045, 0.058] | N/A | 0.970 | 185.2 [212.5] | 331.57 | 329.82 | |
σ2 = c + d · ID + e · ID2 | −0.237 [−0.871, 0.398] | 0.034 [−0.037, 0.106] | 0.002 [0.0003, 0.004] | 0.972 | 206.6 [241.9] | 333.91 | 330.42 | |
Narrowing tunnel | σ2 = c | 0.694 [0.283, 1.075] | N/A | N/A | 0 | 444.3 [435.5] | 358.50 | 358.72 |
c2 = (c · ID)2 | 0.058 [0.054, 0.061] | N/A | N/A | 0.918 | 152.3 [82.5] | 328.62 | 326.06 | |
σ2 = c + d · ID | −0.405 [−0.77, −0.067] | 0.089 [0.064, 0.115] | N/A | 0.869 | 233.8 [238.3] | 337.47 | 335.66 | |
σ2 = c + d · ID2 | 0.135 [0.0008, 0.273] | 0.003 [0.002, 0.003] | N/A | 0.946 | 147.6 [141.2] | 326.91 | 323.84 | |
σ2 = (c + d · ID)2 | 0.142 [−0.048, 0.315] | 0.05 [0.041, 0.06] | N/A | 0.939 | 176.4 [174.5] | 328.47 | 325.72 | |
σ2 = c + d · ID + e · ID2 | 0.329 [−0.191, 0.876] | −0.029 [−0.109, 0.049] | 0.004 [0.001, 0.006] | 0.950 | 196.5 [227.8] | 329.39 | 325.14 | |
Circular tunnel | σ2 = c | 1.853 [0.576, 3.215] | N/A | N/A | 0 | 1517.1 [1581.3] | 388.6 | 389 |
σ2 = (c · ID)2 | 0.085 [0.08, 0.089] | N/A | N/A | 0.950 | 431.2 [543.8] | 352.62 | 353.4 | |
σ2 = c + d · ID | −1.873 [−3.088, −0.647] | 0.257 [0.177, 0.337] | N/A | 0.863 | 830.9 [933.6] | 368.26 | 367.76 | |
σ2 = c + d · ID2 | −0.076 [−0.544, 0.424] | 0.007 [0.006, 0.009] | N/A | 0.951 | 530.4 [644.6] | 355.96 | 354.68 | |
σ2 = (c + d · ID)2 | −0.177 [−0.694, 0.185] | 0.092 [0.076, 0.112] | N/A | 0.953 | 552.4 [708.5] | 355.37 | 354.22 | |
σ2 = c + d · ID + e · ID2 | 0.821 [−0.778, 2.346] | −0.118 [−0.316, 0.088] | 0.01 [0.005, 0.02] | 0.960 | 613.6 [901.3] | 356.92 | 353.8 |