As can be seen in Tables 1 through 8, no matter which machine translation service is used, the proposed co-training approach (CoTrain) outperforms all baseline methods on the overall accuracy metric and most other metrics on the two test sets.
(8) Add the reviews in E en E cn with the corresponding labels to L. From the point of view of the algorithm, the unlabeled reviews are added to the model during the bootstrapping phase, and only for these reviews are the labels obtained using an average of the normalized prediction values determined by the component classifiers.