Different application scenarios of paraphrase have different demands on the paraphrasing results and up to now, the widely mentioned criteria include (Zhao et al., 2009;Chen and Dolan, 2011;Metzler et al., 2011): Semantic adequacy, fluency and dissimilarity.
the results show that our method is able to effectively control the self-paraphrase rate and lower down the score of self-BLEU, this is done by both of the process of joint learning and introducing the metric of iBLEU to avoid trivial self-paraphrase.