Table 1.
Feature types and descriptions used in gas classification.
| Type | Features | Description |
|---|---|---|
| Response based features | f1 | The maximum response value |
| Derivative-based features | f2 | Maximum 1st-order derivatives |
| Derivative-based features | f4 | Maximum 2nd-order derivatives |
| Derivative-based features | f5 | Minimum 2nd-order derivatives |
| Time parameter | f6 | response time |
| Time parameter | f7 | Time interval from tg to td1 max |
| Time parameter | f9 | Time interval from tg to td2 max |
| Time parameter | f8 | Time interval from tg to td2 min |
| Integral | f3 | Integral from gas-on to peak |