Before revision:  Second, ROUGE cannot function without a reference summary, which is expensive or impossible to obtain in many cases . Therefore , we introduce a new end-to-end metric system for summary quality assessment by leveraging the semantic similarities of words and/or sentences in deep learning.
After revision:  Second, ROUGE cannot function without a reference summary, which is expensive or impossible to obtain in many cases , is needed. Existing efforts to address the two drawbacks are done separately and have limitations. To holistically address them , we introduce a new end-to-end metric system for summary quality assessment by leveraging the semantic similarities of words and/or sentences in deep learning.