According to the inquiry of UC paper net, the extension of doctoral degree of National Science and Technology University needs to be re-defended under the following circumstances:

1. The author of the thesis fails to complete the revision of the thesis within the specified time, or there are still major problems in the revised thesis, which cannot meet the requirements of the doctoral degree.

2. The defense committee re-evaluated the author's revised paper, and thought that it still needed to be further improved, and clearly put forward the revision opinions.

3. Within the specified time, the author of the paper failed to make any revision according to the requirements of the defense committee, or the revised paper failed to pass the review of the defense committee.