WEBVTT

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(ALEJANDRO) Hello,
I am Alejandro Rodríguez Ascaso,

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lecturer at the Department
of Artificial Intelligence at UNED.

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This is the first
of the videos we are dedicating

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to the operation of a system,

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that is, the characteristics
a system must have

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to ensure that users are able
to activate all its functions,

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to do so
within a reasonable amount of time,

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to avoid the accidental
activation of controls,

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to recover
from any errors we may make,

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and, of course,
to use the system efficiently.

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(FEMALE VOICE) Welcome
to the voice navigation system.

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(MALE VOICE) To select
'Single ticket'...

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To select 'Combined Metro',

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touch the upper left part
of the screen.

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To select 'Monthly pass', touch
the upper right part of the screen.

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To select 'Other tickets', touch
the lower left part of the screen.

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You have selected 'Monthly pass'.

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(ALEJANDRO) In this metro system,
which allows us to buy a ticket,

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a touch screen and a voice
navigation system are used.

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It is therefore useful
for people with visual impairments.

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There is a very close relationship

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between the operation of a system

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and the perception
of the information it generates.

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Why? Because to operate a system,

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we first need to know
where the controls are located,

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to know the state they are in...

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(MALE VOICE) To select
'Monthly pass',

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touch the upper right
part of the screen.

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(ALEJANDRO) And to perceive
the feedback of the operation,

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that is, the confirmation that
a command we have given to the system

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has indeed been carried out.

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(MALE VOICE) You have selected
'Monthly pass'.

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(ALEJANDRO) Of course,
there is also a relationship

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between the operation of a system
and comprehension,

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both of the output it produces
and of its overall functioning.

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(FEMALE NARRATOR) The user operates
the computer using the keyboard.

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(SCREEN READER)
User interfaces of a Digital Home.

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Underline. Test.

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(ALEJANDRO)
Víctor can use the product

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completely
without needing to use a mouse.

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Firstly, because the software
allows all its functions

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to be activated
using only the keyboard.

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We can all experience this,
for better or for worse,

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depending on the situation.

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For instance, when our mouse
breaks down or becomes misconfigured,

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how many times has that happened?

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We then need to use the keyboard
to access certain software functions.

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In addition, Víctor can both
perceive and input information

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into the computer perfectly.

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How does he manage it?

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Because he receives output
information in the form of speech,

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which he can easily perceive,

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and to input information,

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he uses
tactile markers on the keyboard

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that allow him to identify
where the F, J, and 5 keys are.

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Moreover, because the keyboard
follows a standard layout,

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he can infer
where the other keys are,

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based on his prior knowledge
of that standard arrangement.

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Some users do not use touch directly,

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but instead use, for example,

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a pointer stick
or head wand to operate the keyboard.

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Therefore,
all functions must be accessible

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without requiring direct touch.

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Some users
also need there to be no obstacles

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preventing them from reaching
or pressing all buttons.

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(MALE NARRATOR) Felipe selects
a web address in his browser.

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He does so by combining chin tapping

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with a scanning system
that moves across the screen,

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the direction and speed of which
he can control.

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(ALEJANDRO) Felipe uses a mouse
emulator and a scanning device.

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This method allows him
to operate the product

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without needing to perform
simultaneous actions,

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apply strength or pressure,
grasp or pinch,

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rotate his wrists,
maintain physical contact,

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move with precision,
or use his hands.

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He can also adjust
the speed and acceleration

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of the input devices.

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(for example, the speed at which
the scanning cursor moves)

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and access all the system's functions

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from his keyboard emulator
with visual feedback.

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We have all been frustrated
by interactive telephone systems

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when trying to contact, for example,

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the customer service department
of our mobile phone operator.

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It can be quite nerve-racking,

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sometimes
because the menus are too complex,

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or because the system

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does not recognise
our voice correctly.

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For that reason,

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and to ensure that people
with speech impairments

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can use these systems,

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they must offer
an alternative input method

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(for example, by allowing the user

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to make selections
using the telephone keypad tones).

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Another interesting case

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is that of ICT devices
designed differently

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for people who use
only their right hand

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or only their left hand.

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The mouse is a good example.

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If a left-handed person tries to use
a mouse configured by default

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for right-handed users,
they will face difficulties.

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Therefore,
it must be possible to reconfigure

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the right and left button functions.

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ICT products must be operable
with either the right or left hand.

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It is increasingly common for systems

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to allow a computer to be
switched on using a fingerprint,

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or to activate or deactivate
an alarm system

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in an office in the same way.

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However, some people
are unable to extend their hand

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or place their finger on a sensor.

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For this reason,
biometric identification systems

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must offer alternatives for those
who cannot use that function.

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(FEMALE NARRATOR) Using a chin switch
and a scanning system

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that moves vertically
and horizontally

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across an on-screen keyboard,

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a person types
letter by letter into a document

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that also includes
a word prediction system.

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(ALEJANDRO) In this video,
we have seen how Felipe enters text

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into the system through
a virtual keyboard,

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a chin-operated mouse,
and an on-screen keyboard.

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This is becoming increasingly common.

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For example, on mobile phones

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that now allow us to dictate
search terms orally in Google.

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Therefore,
it is important that systems

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offer alternative input methods
for entering text.

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For repetitive actions,

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it is often
convenient to use keyboard shortcuts,

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though they can sometimes be
difficult to remember.

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Another accessibility requirement
is therefore

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to make
these keyboard shortcuts visible

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and also accessible in a way

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that does not require
pressing multiple keys at once.

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Some time ago, when we still used
public telephone booths,

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it was annoying
to insert several coins,

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take too long to dial the number,

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and have the booth
automatically return all the coins,

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forcing us to start over.

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Something similar happens

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with this metro ticket
renewal system.

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(MALE VOICE) Operation cancelled.

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(ALEJANDRO)
The user took a little longer

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to insert the monthly pass
they wished to renew,

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so the system timed out
and restarted the process.

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Systems should give us
enough time to complete our actions,

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or, in other words,
they should offer an alternative mode

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to complete a function according
to the user's time constraints.

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They should also give users
sufficient time

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to read
all the displayed information.

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In conclusion,
we have seen in this video

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the important relationship
between system operation

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and the perception
of the information it produces,

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as well as an understanding
of how it works overall.

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We have also looked
at accessibility requirements

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related to operating
all available functions

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in a reasonable amount of time.

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Other aspects of accessibility
concerning system operation,

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such as avoiding
accidental control activation,

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recovering from errors,
and using a product efficiently,

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will be addressed in a future video.