表 4. Comparison of training time and classification accuracy under different number of features ().

不同特征数量下训练用时及分类准确率对比（）

特征数量	训练用时/s	分类准确率
20	10.40 ± 1.673 3	0.442 3 ± 0.023 2
30	10.80 ± 0.447 2	0.692 0 ± 0.019 5
40	11.00 ± 0.707 1	0.816 6 ± 0.039 7
50	11.60 ± 0.894 4	0.725 9 ± 0.051 1
60	13.80 ± 1.643 1	0.705 3 ± 0.075 3
70	15.40 ± 1.140 2	0.667 4 ± 0.142 3
77	18.00 ± 2.000 0	0.688 5 ± 0.052 8