Investigating design issues of context-aware mobile guides for people with visual impairments

While mobile wayfinding systems for visually impaired people offer huge potential, most insufficiently address the differences between visual impairments and contextual environments, and offer very little context-awareness - usability issues of which are vital in supporting independent mobility. Participants experiencing a loss of central vision, loss of peripheral vision, and total vision loss made up three groups. Our multidisciplinary model of context was used to design a user study, which involved asking participants to walk to pre-determined outdoor and indoor landmarks. Significant differences were found between groups relating to information requirements, and the environmental cues encoded and used to orientate and navigate. The study also found differences between indoor and outdoor contexts. It was concluded that what is meaningful to one form of visual impairment is incidental to another. These issues need to be captured and accounted for if wayfinding systems are to be usable

Design and initial validation of the Raster method for telecom service availability risk assessment

Crisis organisations depend on telecommunication services; unavailability of these services reduces the effectiveness of crisis response. Crisis organisations should therefore be aware of availability risks, and need a suitable risk assessment method. Such a method needs to be aware of the exceptional circumstances in which crisis organisations operate, and of the commercial structure of modern telecom services. We found that existing risk assessment methods are unsuitable for this problem domain. Hence, crisis organisations do not perform any risk assessment, trust their supplier, or rely on service level agreements, which are not meaningful during crisis situations. We have therefore developed a new risk assessment method, which we call RASTER. We have tested RASTER using a case study at the crisis organisation of a government agency, and improved the method based on the analysis of case results. Our initial validation suggests that the method can yield practical results