Gesture language use in natural UI: Pen-based sketching in conceptual design

Natural User Interface is one of the important next generation interactions. Computers are not just the tools of many special people or areas but for most people. Ubiquitous computing(1) makes the world magic and more comfortable. In the design domain, current systems, which need the detail information, cannot conveniently support the conceptual design of the early phrase. Pen and paper are the natural and simple tools to use in our daily life, especially in design domain. Gestures are the useful and natural mode in the interaction of pen -based. In natural UI, gestures can be introduced and used through the similar mode to the existing resources in interaction. But the gestures always are defined beforehand without the users' intention and recognized to represent something in certain applications without being transplanted to others. We provide the gesture description languages (GDL) to try to cite the useful gestures to the applications conveniently. It can be used in terms of the independent control resource such as menus or icons in applications. So we give the idea from two perspectives: one from the application-dependent point of view and the other from the application-independent point of view.