Table 7.
Evaluation metrics for various representative hyperparameter configurations.
| Layers | Activation | Pearson | Spearman | Procrustes | GMM | Comments |
|---|---|---|---|---|---|---|
| - | - | 0.916 | 0.896 | 0.272 | 0.814 | PCA |
| [ ] | ReLU | 0.940 | 0.920 | 0.226 | 0.695 | The approximate linearity of the ReLU activation function of this model favours distance preservation |
| [ ] | Sigmoid | 0.917 | 0.906 | 0.240 | 0.543 | The non-linearity of the Sigmoid activation affects distance metrics slightly and improves density metrics |
| [3] | Sigmoid | 0.840 | 0.830 | 0.301 | 0.321 | It balances distance preservation and density metric results |
| [5,4,3] | ReLU | 0.635 | 0.622 | 0.505 | 0.104 | It is a complex model with good density metric results but produces dense points in the latent dimension not apt for visualisation of patient trajectories over time. In addition, distance metric results show that distances are not preserved and therefore it is inadequate for similarity-based retrieval |