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The optimum network architecture of the three selected models_
| Factors | DNN Model | SRA-DNN Model | PCA-DNN Model |
|---|---|---|---|
| Number of neurons | 30 | 20 | 30 |
| Number of neurons (output layer) | 20 | 20 | 20 |
| Number of layers | 5 | 5 | 5 |
| Total trainable parameters | 2,061 | 1,921 | 2,041 |
| Activation function (output layer) | Linear | Linear | Linear |
| Activation function | relu | relu | relu |
| Optimisation function | Adam | Adam | Adam |
| Loss function | mse | mse | mse |
| Number of features | 17 | 10 | 15 |
Performance of selected optimum DNN, SRA-DNN and PCA-DNN models_
| Model | Wall times | CPU time | Epoch | MAE | MAPE | MSE |
|---|---|---|---|---|---|---|
| DNN | 3.02 s | 3.32 s | 20 | 0.43 | 27% | 0.42 |
| SRA-DNN | 6.06 s | 7.05 s | 30 | 0.42 | 22% | 0.39 |
| PCA-DNN | 6.27 s | 7.27 s | 160 | 0.23 | 14% | 0.10 |
PC attributes – numerical and categorical labels and frequencies_
| Identifier | Feature name | Mean | Standard deviation | Feature type | Feature attributes | Frequency of attribute |
|---|---|---|---|---|---|---|
| PC1 | Area | 313.88 | 105.94 | Numerical | (89, 286] | 497 |
| (286, 482] | 664 | |||||
| (482, 678] | 74 | |||||
| (678, 874] | 7 | |||||
| (874, 1070] | 2 | |||||
| PC2 | Room | 3.08 | 0.86 | Numerical | 1 bedroom | 45 |
| 2 bedrooms | 168 | |||||
| 3 bedrooms | 776 | |||||
| 4 bedrooms | 166 | |||||
| 5 bedrooms | 79 | |||||
| 6 bedrooms | 9 | |||||
| 7 bedrooms | 1 | |||||
| PC3 | Saloon | 1.04 | 0.20 | Numerical | 0 saloon | 3 |
| 1 saloon | 1,191 | |||||
| 2 saloons | 50 | |||||
| PC4 | Building age | 11.14 | 11.95 | Numerical | 0–4 years | 595 |
| 5–10 years | 218 | |||||
| 11–15 years | 163 | |||||
| 16–20 years | 135 | |||||
| 21–25 years | 71 | |||||
| 26–30 years | 38 | |||||
| ≥31 years | 24 | |||||
| PC5 | No. of stories | 7.27 | 2.66 | Numerical | 1–15 stories | Illustrated in Figure 2a. |
| PC6 | Floor No. | 3.90 | 3.05 | Numerical | –1 to 15 floor | Illustrated in Figure 2b. |
| PC7 | No. of bathrooms | 1.61 | 0.59 | Numerical | 1 bathroom | 549 |
| 2 bathrooms | 635 | |||||
| 3 bathrooms | 54 | |||||
| 4 bathrooms | 6 | |||||
| PC8 | Balconies | 0.05 | 0.22 | 1 | With balcony | 1,182 |
| 2 | Without balcony | 62 | ||||
| PC9 | Furniture | 0.97 | 0.18 | 1 | Furnished | 42 |
| 2 | Not furnished | 1,202 | ||||
| PC10 | Amenities | 0.68 | 0.46 | 1 | Amenities included | 394 |
| 2 | Amenities not included | 850 | ||||
| PC11 | Credit availability | 0.10 | 0.30 | 1 | Available | 1,118 |
| 2 | Unavailable | 126 | ||||
| PC12 | Video call | 0.53 | 0.50 | 1 | Available | 589 |
| 2 | Unavailable | 655 | ||||
| PC13 | Swap option | 0.84 | 0.37 | 2 | Ready for swap | 200 |
| No swap | 1,044 | |||||
| PC14 | Heating system | 0.78 | 1.66 | 1 | Natural gas | 1,006 |
| 2 | Central | 173 | ||||
| 3 | gas stove | 6 | ||||
| 4 | Air conditioning | 6 | ||||
| 5 | Stove | 29 | ||||
| 6 | Underfloor heating | 17 | ||||
| 7 | Fireplace | 7 | ||||
| PC15 | Occupancy condition | 0.54 | 0.80 | 1 | Unoccupied | 812 |
| 2 | Occupied by owner | 243 | ||||
| 3 | Under rent | 189 | ||||
| PC16 | Selling agency | 0.18 | 0.46 | 1 | Real-estate agent | 1,052 |
| 2 | Construction company | 36 | ||||
| 3 | Private owners | 156 | ||||
| PC17 | Neighbourhood | 42 | 1–42 districts | Illustrated in Figure 2c. |