Table 7.

Learning difficulties of ${\mathcal{ℬ}}_{UDD}$, ${\mathcal{ℬ}}_{SDD}$ and ${\mathcal{ℬ}}_{IDD}$ evaluated by KLD and JSD, respectively. The smaller the KLD value is, the more difficult to be learned the batch set is. The smaller the JSD value is, the less difficult to be learned the batch set is.

Method	${\mathit{ℬ}}_{\mathit{U}\mathit{D}\mathit{D}}$	${\mathit{ℬ}}_{\mathit{S}\mathit{D}\mathit{D}}$	${\mathit{ℬ}}_{\mathit{I}\mathit{D}\mathit{D}}$
KLD	0.124	0.103	0.090
JSD	33.3 × 10−3	12.8 × 10−3	8.97 × 10−3