kami kitt assistive technology chapter 7 human/ assistive technology interface
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KAMI KITTASSISTIVE TECHNOLOGY
Chapter 7
Human/ Assistive Technology Interface
T H E H U M A N / T E C H N O L O G Y I N T E R FA C E
Is a major part of the assistive technology component
of the human activity assistive technology model
There are 3 elements of human/technology that
contribute to the operation of a device.
1. The control interface
2. The selection set
3. The selection method
CONTROL INTERFACE
Is the hardware by which the human in the
assistive technology system operates or controls a
device. Also known as an impute device. (e.g.
keyboard, joystick)
Selection Set: The items available from which
choices are made. These sets are represented by
written words, letters, and sentences. The size,
modality, and the type are based on the users need.
SELECTION METHODS
There are 2 basic methods
1.Direct Selection: The consumer indicates his
choice by using voice, finger, hand, eye, or other
body movement
2.Indirect Selection : Uses the method of scanning
which uses switches.
Scanning : requires good visual tracking skills, a high
degree of attention, and the ability to sequence. It requires
very little motor control to make a selection.
Directed Scanning: Allows user to activate the control
interface to select the direction of the scan, vertical or
horizontal.
Coded Access is a sequence of movements a individual
uses to impute code for each item. (e.g. Morse code)
THE PROCESSOR
This is a set of device functions which is referred
to as the Command Domain. Such as a joystick on a
powered wheelchair. Pushing it up is transferred as
forward movement of the wheelchair, down is
transferred as reverse, left moves chair to the left,
and pushing it right makes the chair move to the
right.
KEYB OARD AND MOUSE EMULATING INTERFACES
Transport Access describes 2 fundamental concepts
1.100% of the functions of the computer must be adapted if the
user who has a disability is to have full access.
2.All application software that runs the unmodified computer must
also run on the adapted computer.
There must be a bridge between the control interface and the
computer to use many of the alternatives to keyboard or mouse,
such as an expanded keyboard or a single switch, to access the
computer.
GENERAL INPUT DEVICE -EMULATING INTERFACES
Or GIDEI: defines the characteristics of a special processor that
translates or decodes the signals from the control interface so they
match the command domain requirements of the computer.
A GIDEI set up consists of 3 parts
1.Input Method
2.Overlay
3.Options
See page 219 of text Box 7-3 for more details as well as Box 7-1 on
same page for the major features of commonly used GIDEI
EMULATORS
Mouse Emulation :Substitutes a set of keys, a scanning array, or
Morse code characters for mouse functions.
Emulators use built in synthetic speech feedback to allow the
user to receive auditory and visual prompting and feedback. This
is useful for young children who may not be able to read, for
visually impaired individuals, and for added input for persons with
learning disabilities
Coded Access: A sequence of movements a individual uses to
impute code for each item. (e.g. Morse code)
GRAPHICAL USER INTERFACE
GUI is characterized by 3 distinguishing features
1.Mouse pointer which is moved across the screen.
2.A graphical menu bar, which appears on the
screen.
3.One or more windows , which provides a menu of
choices
CHARACTERISTICS OF CONTROL INTERFACES
Spatial Characteristics
1.Overall physical size, shape, and weight
2.The number of available targets contained within
the control interface
3.The size of each target
4.The spacing between targets.
Activation Characteristics: the method of
activation, deactivation effort, displacement,
flexibility, and durability of a control interface.
Sensory Characteristic: Auditory, somatosensory,
and visual feedback produced during the activation
of a control interface.
ENHANCEMENTS
Rate Enhancement: Augmentative and alternative
communication and computer access approaches that result in
the number of characters generated being greater the number of
selections the individual makes.
Direct Selection Rate Enhancement: deals with encoding
techniques and prediction techniques.
Scanning Rate Enhancement: is based on placement of the most
frequently used characters near the beginning so that they are
scanned first
Control Enhancers: Aids and strategies that enhance or extent the
physical control a person has available to use a controlled interface.
Control interfaces for Direct Selection includes:
• Various types of keyboards
• Pointing interfaces
• Speech recognition
• Eye gaze
• Gesture recognition
• Cortical signals
CONTROL ENHANCERS
Aids and strategies to enhance or extend the physical
control a person has available to use a control interface
Interface positioning, arm supports, mouth sticks head
pointers, and hand pointers.
Control interfaces for Direct Selection include: Various
types of key boards, pointing interfaces, speech
recognition, eye gaze, gesture recognition, and cortical
signals
DIFFERENT TABLES TO VIEW
See figure 7-12 page 238 for different types of keyboards.
See Table 7-9 page 248 for Alternative Electronic pointing
interfaces
See Table 7-8 page 242 for Speech recognition Interfaces
See Table 7-15 page 269 for types of Text-to-Speech Systems
used in assistive Technologies.
See figure 7-9 on page 233 for Selecting a control interface
for an individual.
EYE CONTROL SYSTEMS
There are 2 basic types of systems
1.The first type uses IR video camera mounted below the computer
screen . (e.g. TOBII. If you ever want to see how one runs, contact
me. My little brother uses one at school every day. )
2.The second one used a head mounted viewer that tracks movement
of one eye such as the Vision Key.
Both types provide the user with computer access for written or
verbal communication, internet access, environmental control, and
telephone operation
ALTERNATIVE ELECTRONIC POINTING
Keypad mouse: mouse movement is replaced by
keys that move the mouse cursor
Trackball: looks like inverted mouse; a ball is
mounted on a stationary base. On the base there are
buttons that provide different functions
Continuous input joysticks used for powered
mobility and for computer use.
Head-controlled mouse: the user wears a sensor on
the head, which is detected by a unit on the
computer.
Light pointers and light sensors emit a light beam
that can be used to point to objects.
MOUNTS FOR CONTROL INTERFACE
Keyboards can be placed on stands or easels, some
can be mounted to wheelchairs.
The most common mounting locations are
attachment to a table, desk, wheelchair, or a persons
body.
There are flexible and fixed mounting systems for
individuals who require changes in their position
because of fluctuating needs or skills.
SPEECH OUTPUTS
There are 2 types of speech used in Assistive
Technologies
1.Digital recording: Human speech is stored in
electronic memory circuits for later retrieval.
2.Speech Synthesis: which is the generation of
human sounding speech by use of electronic circuits
and computer software.
QUIZ
http://
www.onlineexambuilder.com/my-dashboard/my-quizz
es/item3240
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