Adapting user interfaces for visually disabled users

Recent developments in the design of human-machine interfaces have resulted in interfaces which make access to computer-based equipment more difficult for visually disabled people. The aim of this project was to explore whether it is possible to adapt such interfaces so as to make them usable by people who cannot see a screen. The approach adopted was based upon two principles: the replacement of visual interlace entities by auditory analogues and appropriately constraining the resultant interlace. Two forms of sound were used to embody the auditory interface: musical tones and synthetic speech. The 'auditory screen' so produced consists of a grid of 'auditory objects', each of which is associated with a spatial location, a tone, a name and an action. In order to test the principles a word processing program was designed and implemented to demonstrate how a visual program might be adapted to be accessed through such an interface. This program was evaluated with the assistance of a number of visually disabled testers. They were trained to use the word processor through completing a graded set of exercises. Data were obtained in a number of ways during and after the completion of the exercises. Since the auditory interface had some novel components, special evaluation methods were applied. The nature of the interaction was analyzed, using an approach based on work on keystroke models of visual interfaces. This yielded a simple model of the 'hand-ear' coordination employed, which forms a basis for prediction of user behaviour. It was also necessary to evaluate aspects of the program, such as ease-of-learning and these were investigated by interviewing the subjects. The results demonstrate that the approach is viable. The thesis also discusses a number of problems in using such an interface, most of which are related to the memory load on the user

Conceptual Design Standards for eXternal Visibility System (XVS) Sensor and Display Resolution

NASA is investigating eXternal Visibility Systems (XVS) concepts which are a combination of sensor and display technologies designed to achieve an equivalent level of safety and performance to that provided by forward-facing windows in today s subsonic aircraft. This report provides the background for conceptual XVS design standards for display and sensor resolution. XVS resolution requirements were derived from the basis of equivalent performance. Three measures were investigated: a) human vision performance; b) see-and-avoid performance and safety; and c) see-to-follow performance. From these three factors, a minimum but perhaps not sufficient resolution requirement of 60 pixels per degree was shown for human vision equivalence. However, see-and-avoid and see-to-follow performance requirements are nearly double. This report also reviewed historical XVS testing

Department of Defense Dictionary of Military and Associated Terms

The Joint Publication 1-02, Department of Defense Dictionary of Military and Associated Terms sets forth standard US military and associated terminology to encompass the joint activity of the Armed Forces of the United States. These military and associated terms, together with their definitions, constitute approved Department of Defense (DOD) terminology for general use by all DOD components

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 257

This bibliography lists 331 reports, articles and other documents introduced into the NASA scientific and technical information system in March 1984