Since retrieval of the FTP document will have failed, an error message to that effect is displayed.
由于FTP文档的检索将会失败，因此会显示有关这种情况的错误消息。
2
If the retrieval was unsuccessful, an error message is displayed to the user who can try again by reloading the page.
如果检索失败，则将一个错误消息显示给用户，用户可通过重新加载页面来再次尝试。
3
In this paper an identifier (id) watermarking algorithm is proposed, which has the characteristics of error-correct, high redundance and adaptive watermark retrieval.