Direct-touch interaction on mobile phones revolves around screens that compete for visual attention with users" realworld tasks and activities. This paper investigates the impact of these situational impairments on touch-screen interaction. We probe several design factors for touch-screen gestures, under various levels of environmental demands on attention, in comparison to the status-quo approach of soft buttons. We find that in the presence of environmental distractions, gestures can offer significant performance gains and reduced attentional load, while performing as well as soft buttons when the user"s attention is focused on the phone. In fact, the speed and accuracy of bezel gestures did not appear to be significantly affected by environment, and some gestures could be articulated eyes-free, with one hand. Bezel-initiated gestures offered the fastest performance, and mark-based gestures were the most accurate. Bezel-initiated marks therefore may offer a promising approach for mobile touch-screen interaction that is less demanding of the user"s attention.

Holographically formed polymer dispersed liquid crystal (H-PDLC) displays are investigated in terms of their electro-optic performance parameters and their potential as capable full color display systems. It is demonstrated that the transmission-voltage curve can be modified by low concentrations of chiral dopants, increasing the steepness of the response curve. To probe the details of full-color reflective H-PDLC displays, we invoke a generalized colorimetric/photometric analysis to estimate the display reflectance, white-point, and chromaticity diagram for a vertically integrated stack of red, green, and blue H-PDLC displays.