Table 2.
Optimized model parameters for all five subjects with means and standard deviations
| Sit-to-stand |
Head-up-tilt |
|||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Param | Init val |
I | II | III | IV | V | Mean | I | II | III | IV | V | Mean |
P value |
| kS | 2.0 | 10.725 | 1.410 | 1.923 | 1.519 | 1.930 | 3.50 ± 4.0 | 4.251 | 1.296 | 5.785 | 2.209 | 1.728 | 3.05 ± 1.9 | 0.82 |
| kI | 1.5 | 1.315 | 0.473 | 0.567 | 0.080 | 1.205 | 0.73 ± 0.5 | 1.594 | 0.067 | 1.582 | 0.003 | 0.344 | 0.72 ± 0.8 | 0.98 |
| kL | 2.0 | 3.767 | 0.255 | 0.515 | 1.446 | 1.063 | 1.41 ± 1.4 | 5.351 | 0.146 | 1.835 | 3.741 | 0.778 | 2.37 ± 2.2 | 0.43 |
| τS | 1.0 | 0.033 | 0.699 | 1.414 | 0.851 | 1.110 | 0.82 ± 0.5 | 1.983 | 2.852 | 0.008 | 1.722 | 0.273 | 1.37 ± 1.2 | 0.38 |
| τI | 5.0 | 7.344 | 5.915 | 2.841 | 4.406 | 7.414 | 5.58 ± 2.0 | 9.808 | 4.702 | 4.903 | 6.608 | 5.468 | 6.30 ± 2.1 | 0.59 |
| τL | 250.0 | 286.420 | 262.190 | 266.414 | 248.767 | 246.352 | 262.03 ± 16 | 217.65 | 252.53 | 255.65 | 261.45 | 243.76 | 246.2 ± 17 | 0.17 |
| τnor | 1.0 | 3.406 | 1.612 | 1.548 | 1.762 | 3.741 | 2.41 ± 1.1 | 5.060 | 0.989 | 24.919 | 2.559 | 2.523 | 7.21 ± 10 | 0.32 |
| τach | 1.0 | 1.317 | 3.169 | 0.795 | 0.911 | 3.952 | 2.03 ± 1.4 | 0.059 | 1.642 | 3.369 | 2.274 | 5.032 | 2.48 ± 1.9 | 0.68 |
| α | 1.0 | 0.932 | 2.396 | 3.068 | 1.260 | 4.046 | 2.34 ± 1.3 | 0.143 | 1.925 | 2.055 | 0.857 | 2.592 | 1.59 ± 1.0 | 0.29 |
| η | – | 1.827 | 0.970 | 1.158 | 1.249 | 1.196 | 1.28 ± 0.3 | 1.106 | 2.885 | 2.193 | 1.396 | 3.668 | 2.25 ± 1.1 | 0.08 |
| ξs | – | 8.273 | 5.777 | 9.084 | 9.024 | 6.095 | 7.65 ± 1.6 | 8.002 | 6.909 | 4.065 | 4.924 | 7.866 | 6.35 ± 1.8 | 0.26 |
| ξp | – | 0.389 | 1.081 | 0.470 | 0.927 | 0.810 | 0.78 ± 0.3 | 0.763 | 0.701 | 0.447 | 0.881 | 0.710 | 0.70 ± 0.2 | 0.57 |
| u 0 | 1.0 | 1.015 | 0.387 | 0.698 | 0.596 | 3.435 | 1.14 ± 1.3 | 0.170 | 0.033 | 0.498 | 0.242 | 0.160 | 0.22 ± 0.2 | 0.16 |
| tstart | 15.0 | 14.412 | 12.020 | 14.383 | 11.025 | 12.565 | – | 14.089 | 19.135 | 16.175 | 14.699 | 15.562 | – | – |
| tper | 5.0 | 5.210 | 4.702 | 6.839 | 7.141 | 4.312 | 5.64 ± 1.3 | 6.102 | 9.655 | 3.035 | 6.637 | 10.722 | 7.23 ± 3.1 | 0.31 |
| τd | 7.0 | 8.136 | 9.661 | 5.859 | 6.766 | 6.869 | 7.46 ± 1.5 | 12.559 | 6.331 | 1.658 | 6.163 | 12.095 | 7.77 ± 4.6 | 0.99 |
| β | 1.0 | 4.180 | 1.401 | 0.839 | 1.754 | 5.960 | 2.83 ± 2.2 | 0.192 | 0.223 | 2.201 | 2.294 | 2.023 | 1.39 ± 1.1 | 0.22 |
| Iterations | 1587 | 1463 | 979 | 1412 | 1215 | 1331 ± 238 | 1286 | 822 | 1175 | 904 | 1204 | 1078 ± 203 | – | |
| J | 1.30E-3 | 6.87E-4 | 1.70E-3 | 1.80E-3 | 6.7E-4 | 1.2E-3 ± 5.4E-4 | 1.40E-3 | 5.50E-4 | 5.80E-3 | 8.93E-4 | 3.41E-4 | 1.8E-3 ± 2.3E-3 | – | |
| R | 0.96 | 0.92 | 0.95 | 0.90 | 0.97 | 0.94 ± 0.03 | 0.90 | 0.58 | 0.79 | 0.89 | 0.98 | 0.83 ± 0.15 | 0.13 | |
The last three rows show the number of iterations needed for the Nelder–Mead method to converge, the least squares cost J at time of convergence, and the correlation coefficient between computed and measured values of heart rate
Numbers in bold indicate paramets that are significantly different between the two tasks