Table 2 N-gram feature templates of the ith character
From: Multi-task learning for Chinese clinical named entity recognition with external knowledge
Types | Template |
|---|---|
2-gram | \(x_{i-1}x_i, x_ix_{i+1}\) |
3-gram | \(x_{i-2}x_{i-1}x_i, x_ix_{i+1}x_{i+2}\) |
4-gram | \(x_{i-3}x_{i-2}x_{i-1}x_i, x_ix_{i+1}x_{i+2}x_{i+3}\) |
5-gram | \(x_{i-4}x_{i-3}x_{i-2}x_{i-1}x_i, x_ix_{i+1}x_{i+2}x_{i+3}x_{i+4}\) |
6-gram | \(x_{i-5}x_{i-4}x_{i-3}x_{i-2}x_{i-1}x_i, x_ix_{i+1}x_{i+2}x_{i+3}x_{i+4}x_{i+5}\) |