Table 5 Some key symbols and their meanings.
From: An efficient method for identifying surface damage in hydraulic concrete buildings
Notations | Descriptions | Notations | Descriptions |
|---|---|---|---|
d | Dimensionality of the data | \(\textrm{X} \in R^{n \times d}\) | Data matrix |
n | Number of samples | \(\mu \in R^{d}\) | Overall sample mean vector |
\(n_i\) | Number of samples in class i | \(\mu _{k} \in R^{d}\) | Mean vector of samples in class k |
c | Number of classes | \(a \in R^{d}\) | Projection vector |
l | Number of selected features | \(\textrm{A} \in R^{d \times l}\) | Projection matrix |
\(x_i \in R^{d}\) | The i-th sample | \(\mathrm{S_{w}} \in R^{d \times d}\) | The intra-class scatter matrix |
\(\textrm{X}^{(k)} \in R^{n_i \times d}\) | Samples from class k | \(\mathrm{S_{b}} \in R^{d \times d}\) | The inter-class scatter matrix |
