Developing the mechanism of recovery from error and user interface evaluation metrics, and proposing user model

人都会犯错误。你无法想象用户在计算机系统上没有任何错误操作。因此，如何防止用户犯可预见的错误，并在错误发生时允许用户恢复他的工作，一直是人机交互中非常重要的课题。对于恢复操作，用户可能希望选择一个命令来撤消或重做，这称为基于命令的恢复操作；用户也可能希望通过撤销和重做选择一个对象来恢复其状态，这称为基于对象的恢复操作。大多数撤消模型是基于命令的撤消模型，不允许基于对象的恢复操作。本文提出了两种撤销模型：基于对象的线性撤销模型和基于对象的非线性撤销模型。两种撤销模型都可以支持基于对象的恢复操作。我们提出并开发了一个新的用户界面工具来直接选择UNDO/REDO机制。可视化的历史对话框为用户提供了一个所见即所得的用户界面，以便用户可以更有效地找到要撤消/重做的命令。在未来一代的历史表示中，显示一组或多个特定对象的历史的能力将是一个有用的功能。

All men make mistakes. You cannot image that the user works on a computer system without any mistake operation. Therefore, to prevent the user from making predictable mistakes and allow the user to recover his work when a mistake happens are always very important topics of human computer interaction.1. As for recovery operations, the user may want to select a command to undo or redo, this is called as command-based recovery operation ; the user may also want to select an object to recover its state by undo and redo, this is called as object-based recovery operation. Most undo models are command-based undo models and do not allow object-based recovery operation. In this project, two undo models are proposed : the object-based linear undo model and the object-based nonlinear undo model. Both undo models can support object-based recovery operation.2. We have proposed and developed a new user interface tool to the direct selective UNDO/REDO mechanism. The visualized history dialog box provides a WYSIWYG user interface to users so that the users can find out the command to be undone/redone in more efficient way. The ability to present the history of a set of one or more particular objects would be helpful feature in the future generation of history presentation.