Pen-based interactions are becoming widely popular on a variety of devices, including tabletPCs, mobile devices and tabletop systems. The digital pens and tablets have evolved considerably and served users in creative industries. A digital pen can sense various auxiliary inputs, such as tilt, pressure and roll. Researchers have explored properties of each channel in isolation of another. Since the human wrist and fingers can operate multiple input channels simultaneously, a natural progression warrants examination of controllability when these channels are operated simultaneously. In this thesis, I explore a class of interaction techniques, a-coord input, which requires users to control two auxiliary channels simultaneously. Through experiments, I explore the design space of a-coord input and investigate the effect of changing the order in which the channels are combined. Furthermore, I investigate its effectiveness for discrete and continuous selection tasks. Finally, this thesis shows the value of a-coord input through several applications.

Pen-based interactions are becoming widely popular on a variety of devices, including tabletPCs, mobile devices and tabletop systems. The digital pens and tablets have evolved considerably and served users in creative industries. A digital pen can sense various auxiliary inputs, such as tilt, pressure and roll. Researchers have explored properties of each channel in isolation of another. Since the human wrist and fingers can operate multiple input channels simultaneously, a natural progression warrants examination of controllability when these channels are operated simultaneously. In this thesis, I explore a class of interaction techniques, a-coord input, which requires users to control two auxiliary channels simultaneously. Through experiments, I explore the design space of a-coord input and investigate the effect of changing the order in which the channels are combined. Furthermore, I investigate its effectiveness for discrete and continuous selection tasks. Finally, this thesis shows the value of a-coord input through several applications.