Table 3 Summary of error evaluation criteria.
From: Soft-computing models for predicting plastic viscosity and interface yield stress of fresh concrete
No. | Metric | Abbreviation | Formula | Range | Suggested value |
|---|---|---|---|---|---|
1. | Mean absolute error | MAE | \(\:\frac{{\Sigma\:}\:|\text{x}\:-\:\text{y}|}{\text{N}}\) | \(\:0\:\text{t}\text{o}+{\infty\:}\) | Close to zero |
2. | Root mean square error | RMSE | \(\:\sqrt{\frac{{\sum\:(\text{x}\:-\:\text{y})}^{2}}{\text{N}}}\) | \(\:0\:\text{t}\text{o}+{\infty\:}\) | Close to zero |
3. | Coefficient of determination | \(\:{R}^{2}\) | \(\:1-\frac{\sum\:{\left(x-y\right)}^{2}}{\sum\:{\left(y-{y}_{mean}\right)}^{2}}\) | \(\:0\:\text{t}\text{o}\:1\) | \(\:{R}^{2}>0.8\) |
4. | Performance index | PI | \(\:\frac{\text{R}\text{R}\text{M}\text{S}\text{E}}{1+\text{R}}\) | \(\:0\:\text{t}\text{o}+{\infty\:}\) | \(\:\text{P}\text{I}<0.2\) |
6. | Objective Function | OF | \(\:\left(\frac{{\text{N}}_{\text{T}\text{r}\text{a}\text{i}\text{n}\text{i}\text{n}\text{g}}-{\text{N}}_{\text{T}\text{e}\text{s}\text{t}\text{i}\text{n}\text{g}}}{\text{N}}\right){\text{P}}_{\text{T}\text{r}\text{a}\text{i}\text{n}\text{i}\text{n}\text{g}}+2\left(\frac{{\text{N}}_{\text{T}\text{e}\text{s}\text{t}\text{i}\text{n}\text{g}}}{\text{N}}\right){\text{P}}_{\text{T}\text{e}\text{s}\text{t}\text{i}\text{n}\text{g}}\) | \(\:0\:\text{t}\text{o}+{\infty\:}\) | \(\:\text{O}\text{F}<0.2\) |
