Mobile information systems aid first responders in their tasks. Support is often based on mobile maps. People have different preferences for map orientations (heading-up or north-up), but map orientations also have different advantages and disadvantages. In general north-up maps are good for building up situation awareness and heading-up maps are better for navigational tasks. Because of heavily loaded visual modalities, we expect that tactile waypoint information can enhance navigation speed and situation awareness. In this paper we describe an experiment conducted in a synthetic task environment, in which we examined the effect of heading-up and north-up displays on search and rescue performance of first responders, and if adding the tactile display improves performance.

The perceptual satisfaction of a user watching video on a tiny mobile device is constrained by the display capability and network bandwidth. To maximize the user's perceptual satisfaction in this constrained environment, we propose a new method to represent the video content adaptively in real-time on tiny devices according to the user's attention. First, a sampling based dynamic attention model is proposed to obtain and maintain the user's attention in the video streams. Second, based on the most attended regions and sequences extracted, the attention based representation is introduced to achieve a higher perceptual satisfaction on a small display. Experiments with users show the effectiveness of our proposed method in a video surveillance application.

An analysis of context-aware user interfaces shows that adaptation mechanisms have a cost-benefit trade-off for usability. Unpredictable autonomous interface adaptations can easily reduce a system's usability. To reduce this negative effect of adaptive behaviour, we have attempted to help users building adequate mental models of such systems. A user support concept was developed and applied to a context-aware mobile device with an adaptive user interface. The approach was evaluated with users and as expected, the user support improved ease of use, but unexpectedly it reduced learnability. This shows that an increase of ease of use can be realised without actually improving the user's mental model of adaptive systems.

Current Network User Interfaces (NUIs) provide entrances to an enormous amount of Web-based services, bringing about new use problems such as laborious and unsuccessful navigation. Such problems are generally more severe for users with regression of cognitive functions (e.g. for some elderly). This paper identifies four fundamental cognitive determinants of navigation performance that may explain these problems: situation awareness, spatial ability, task-set switching and user control of support. Based on an analysis of these demands and current support functions for navigation, three “refined” support concepts were developed: categorising landmarks, history map and navigation assistant. Via the specification of humancomputer co-operative processes and scenarios, the concepts were implemented for two rather different web-based services. The present paper provides an example implementation of the navigation assistant. The results of the study will feed into a cognitive engineering method for the design of NUIs.