Abstract
We are entering the age of Ubiquitous Computing, and its most distinguished advantage is invisibility of computing. The essence of invisible computing is the invisibility of Human-computer Interaction, as people can focus their attention on the content instead of the tools they are using. This paper studies how to make computers invisible, and proposes a framework of online invisible computing and offline invisible computing. Online invisible computing is Intelligent Human Computer Interaction, where the computers function as intelligent agents; whereas offline invisible computing as in Natural Human Computer Interaction, people are able to use the computers without much conscious effort. This paper focuses the study on offline invisible computing which needs only minimal users' attention when the users are using computers. The paper attempts to realize invisible computing with Affordances, especially designing Action Affordances in computers. In the Ubiquitous Computing age, the computers would not only be invisible but also be embedded in the environment where people are living, so Human-Computer Interaction could not be separated from the environment any more; User & Environment Centred Design (UECD), a new designing method for ubiquitous computing is also proposed in this paper. A Pen Based User Interface system is developed as the first step to invisible computing.