Older Adults with AMD as Co-Designers of an Assistive Mobile Application

In the UK, 20% of people aged 75 years and over are living with sight loss and age-related macular degeneration (AMD) is the most common cause of sight loss in the UK, impacting nearly 10% of those over 80; regrettably, these figures are expected to increase in coming decades as the population ages (RNIB, 2012). This paper reports on the authors’ design activities conducted for the purpose of informing the development of an assistive self-monitoring, ability-reactive technology (SMART) for older adults with AMD. The authors reflect on their experience of adopting and adapting the PICTIVE (Plastic Interface for Collaborative Technology Initiatives through Video Exploration) participatory design approach (Muller, 1992) to support effective design with and for their special needs user group, reflect on participants’ views of being part of the process, and discuss the design themes identified via their PD activities

Computing the Stretch Factor and Maximum Detour of Paths, Trees, and Cycles in the Normed Space

The stretch factor and maximum detour of a graph G embedded in a metric space measure how well G approximates the minimum complete graph containing G and the metric space, respectively. In this paper we show that computing the stretch factor of a rectilinear path in L1 plane has a lower bound of Ω(n log n) in the algebraic computation tree model and describe a worst-case O(σn log2 n) time algorithm for computing the stretch factor or maximum detour of a path embedded in the plane with a weighted fixed orientation metric defined by σ ≥ 2 vectors and a worst-case O(n logd n) time algorithm to d ≥ 3 dimensions in L1-metric. We generalize the algorithms to compute the stretch factor or maximum detour of trees and cycles in O(σn logd+1 n) time. We also obtain an optimal O(n) time algorithm for computing the maximum detour of a monotone rectilinear path in L1 plane