Semantics of time travel in a generative information space

Abstract

This thesis focuses on interactive and computational semantics for manipulating the time-based medium of an evolving information space. The interactive semantics enable the user to engage in linear timeline traversal and non-linear history manipulation. Extended tape recorder metaphor controls, including jog-shuttle based navigation, provide the user with flexible means for operating the software's generative functionalities, and linearly traversing session history. The user can see previews of information space states while traversing the history using the jog-shuttle. We also introduce a door-latch metaphor that enables one of several considered forms of nonlinear history manipulation. Users can change history by retroactively latching an information sample in its position across time. For representing the information space history, we have developed MPEG-like computational keyframe semantics. This representation is in the form of XML, which is generated automatically and converted back to Java by a framework named ecologylab.xml, which was developed as a part of this thesis. These computational keyframe semantics serve as the basis for interaction semantics. A user study was conducted in the form of a design competition, to evaluate these new features. The results indicated that the users do find the time travel features useful and they feel more in-control of the information space with access to time travel features compared to the case when time travel features are not present.