Desire of Use: A Hierarchical Decomposition of Activities and its Application on Mobility of Blind and Low-Vision Individuals.

Abstract

Blind and low-vision individuals often have severely reduced mobility, affecting their quality of life and associated socioeconomic cost. Despite numerous efforts and great technological progress, the only used primary mobility aids are still white canes and seeing-eye dogs. Furthermore, there is a permeating tendency in the field to ignore knowledge of both mobility and the target group, as well as constantly design new metrics and tests that makes comparisons between solutions markedly more difficult. The Desire of Use model is introduced in an effort to promote a more holistic approach; it should be generalizable for any activity by any user, but is here applied on mobility of blind and low-vision individuals by a proposal and integration of parameters. An embodiment of the model is presented and with it we show why popular mobility metrics of today are insufficient to guide design; what tasks and metrics that should provide better understanding; as well as which fundamental properties determine them and are critical to discuss. Desire of Use has been introduced as a tool and a theoretical framework, and a realization has been proposed. Desire of Use offers both a structured perspective of pertinent design challenges facing a given solution, as well as a platform from which to compare test results and properties of existing solutions; in for example the field of electronic travel aids it should prove valuable for designing and evaluating new tests and devices.