36 1 Disability and Assistive Technology Systems

choice may lie between infrared and ultrasonic technology and the selection process would consider factors such as performance, the user interface, reliability, technical specifications and cost.

Assistive technology system attribute – system technology issues At the third level, the assistive technology system can be divided into the following further categories (see Figure 1.6):

•System interface.

•Technical performance.

Specification of the system interface includes whether it is single or multimodal and which modalities are available, for instance speech, text, icons and/or Braille. Technical performance includes a range of factors, such as reliability, robustness, safety features and ease of maintenance.

Assistive technology system attribute – end-user issues At the third level, end-user issues can be further categorised as follows (see Figure 1.6):

•Ease and attractiveness of use.

•Mode of use.

•Training requirements.

•Documentation.

Ease and attractiveness of use includes a range of factors, such as whether the assistive technology is designed to be ‘user friendly’ and intuitive to use, as well as size, weight, portability and appearance. Mode of use includes whether the device is portable or remains in a given location and whether it is stand-alone or forms part of a larger system. Training requirements specify the types of training (different groups of) users are likely to require in order to use the assistive technology successfully. This may involve training before using the technology for the first time and ongoing training. Factors associated with documentation include the formats it is available in, such as on-line and hard copy, how it is structured and whether it is targeted at novice or expert users or there are different sections for both these groups of users.

1.5 Using the Comprehensive Assistive Technology Model

The comprehensive assistive technology model extends the basic structure of the Cook and Hussey HAAT model to encompass a much wider range of attribute components. These are components that the assistive technology engineer may have to consider when constructing or describing a new or an existing assistive technology system. Thus, an important feature of any model is its power in use and in this section some applications of the model are given. First, two of the attribute models are used to give insight into two specific queries:

1.What activity areas should be the focus of assistive technology developments for visually impaired and blind people?

2.Does the CAT model provide further insight into the structure of assistive technology systems?

Following this, a general investigative framework is extracted and used to demonstrate the analysis and synthesis (model specification) capabilities of the CAT model through the presentation of specific case studies.

1.5.1Using the Activity Attribute of the CAT Model to Determine Gaps in Assistive Technology Provision

One of the aims of the development of the modelling framework is to use it to determine where there are gaps in assistive technology system provision. This may lead to the development of assistive technology systems for areas where there are currently no systems available or lead to developments to extend the capabilities of existing systems to offer more options to end-users.

Many assistive technology systems are developed for disabled people with a particular impairment. In addition, assistive technology aims to overcome the barriers to participation resulting from inaccessible infrastructure and social barriers. Therefore the gaps in assistive technology provision result from the current relationship between assistive technologies, infrastructure, social and other barriers and the disabled person. Consequently, adopting a design for all approach and/or making a particular type of infrastructure accessible would remove the need for assistive technology in that area. For instance, currently many lifts do not have Braille or other tactile markings and audio announcements of the lift operations, such as stopping on level 4. Therefore the provision of Braille or other tactile markings and audio announcements should currently be considered as assistive technology. However, due to the requirements of legislation such as the UK Disability Discrimination Act 1995, it is likely that both Braille and other tactile markings and audio announcements will become standardised in lifts in a number of countries. When this happens, Braille and other tactile markings and audio announcements will no longer need to be considered as assistive technology and this will no longer be an area where blind and visually impaired people require assistive technology to overcome the barriers that would otherwise exist. However, even if design for all becomes standard practice, there are still likely to be areas where assistive technology is required.

As is frequently the case in modelling, the categorisation of activities in Figure 1.5a has required trade-offs between comprehensiveness, that is, a very detailed and all encompassing categorisation and complexity. Within these limits the categorisation has been made as general as possible. In addition, to avoid ambiguity and overlap and to give specificity, in some cases decisions have had to be made as to the appropriate category out of several possibilities for a particular activity. After the initial categorisation, a further type of classification of activities can be carried out:

1. Fully accessible without assistive technology.