With the introduction of the handle service in April 2017, you have the URL of the existing content has been changed.
You can access by modifing the red part of the URL as follows.
Before March 2017：
After April 2017：
The reason for the service introduction, please refer to the following URL.(Soryy,Japanese only)
University of the Ryukyus Repository administration Contact Details:
Go to the DSpace home page