(ALEJANDRO) Hello, I am Alejandro Rodríguez Ascaso,
lecturer at the Department of Artificial Intelligence at UNED.
This is the first of the videos we are dedicating
to the operation of a system,
that is, the characteristics a system must have
to ensure that users are able to activate all its functions,
to do so within a reasonable amount of time,
to avoid the accidental activation of controls,
to recover from any errors we may make,
and, of course, to use the system efficiently.
(FEMALE VOICE) Welcome to the voice navigation system.
(MALE VOICE) To select 'Single ticket'...
To select 'Combined Metro',
touch the upper left part of the screen.
To select 'Monthly pass', touch the upper right part of the screen.
To select 'Other tickets', touch the lower left part of the screen.
You have selected 'Monthly pass'.
(ALEJANDRO) In this metro system, which allows us to buy a ticket,
a touch screen and a voice navigation system are used.
It is therefore useful for people with visual impairments.
There is a very close relationship
between the operation of a system
and the perception of the information it generates.
Why? Because to operate a system,
we first need to know where the controls are located,
to know the state they are in...
(MALE VOICE) To select 'Monthly pass',
touch the upper right part of the screen.
(ALEJANDRO) And to perceive the feedback of the operation,
that is, the confirmation that a command we have given to the system
has indeed been carried out.
(MALE VOICE) You have selected 'Monthly pass'.
(ALEJANDRO) Of course, there is also a relationship
between the operation of a system and comprehension,
both of the output it produces and of its overall functioning.
(FEMALE NARRATOR) The user operates the computer using the keyboard.
(SCREEN READER) User interfaces of a Digital Home.
Underline. Test.
(ALEJANDRO) Víctor can use the product
completely without needing to use a mouse.
Firstly, because the software allows all its functions
to be activated using only the keyboard.
We can all experience this, for better or for worse,
depending on the situation.
For instance, when our mouse breaks down or becomes misconfigured,
how many times has that happened?
We then need to use the keyboard to access certain software functions.
In addition, Víctor can both perceive and input information
into the computer perfectly.
How does he manage it?
Because he receives output information in the form of speech,
which he can easily perceive,
and to input information,
he uses tactile markers on the keyboard
that allow him to identify where the F, J, and 5 keys are.
Moreover, because the keyboard follows a standard layout,
he can infer where the other keys are,
based on his prior knowledge of that standard arrangement.
Some users do not use touch directly,
but instead use, for example,
a pointer stick or head wand to operate the keyboard.
Therefore, all functions must be accessible
without requiring direct touch.
Some users also need there to be no obstacles
preventing them from reaching or pressing all buttons.
(MALE NARRATOR) Felipe selects a web address in his browser.
He does so by combining chin tapping
with a scanning system that moves across the screen,
the direction and speed of which he can control.
(ALEJANDRO) Felipe uses a mouse emulator and a scanning device.
This method allows him to operate the product
without needing to perform simultaneous actions,
apply strength or pressure, grasp or pinch,
rotate his wrists, maintain physical contact,
move with precision, or use his hands.
He can also adjust the speed and acceleration
of the input devices.
(for example, the speed at which the scanning cursor moves)
and access all the system's functions
from his keyboard emulator with visual feedback.
We have all been frustrated by interactive telephone systems
when trying to contact, for example,
the customer service department of our mobile phone operator.
It can be quite nerve-racking,
sometimes because the menus are too complex,
or because the system
does not recognise our voice correctly.
For that reason,
and to ensure that people with speech impairments
can use these systems,
they must offer an alternative input method
(for example, by allowing the user
to make selections using the telephone keypad tones).
Another interesting case
is that of ICT devices designed differently
for people who use only their right hand
or only their left hand.
The mouse is a good example.
If a left-handed person tries to use a mouse configured by default
for right-handed users, they will face difficulties.
Therefore, it must be possible to reconfigure
the right and left button functions.
ICT products must be operable with either the right or left hand.
It is increasingly common for systems
to allow a computer to be switched on using a fingerprint,
or to activate or deactivate an alarm system
in an office in the same way.
However, some people are unable to extend their hand
or place their finger on a sensor.
For this reason, biometric identification systems
must offer alternatives for those who cannot use that function.
(FEMALE NARRATOR) Using a chin switch and a scanning system
that moves vertically and horizontally
across an on-screen keyboard,
a person types letter by letter into a document
that also includes a word prediction system.
(ALEJANDRO) In this video, we have seen how Felipe enters text
into the system through a virtual keyboard,
a chin-operated mouse, and an on-screen keyboard.
This is becoming increasingly common.
For example, on mobile phones
that now allow us to dictate search terms orally in Google.
Therefore, it is important that systems
offer alternative input methods for entering text.
For repetitive actions,
it is often convenient to use keyboard shortcuts,
though they can sometimes be difficult to remember.
Another accessibility requirement is therefore
to make these keyboard shortcuts visible
and also accessible in a way
that does not require pressing multiple keys at once.
Some time ago, when we still used public telephone booths,
it was annoying to insert several coins,
take too long to dial the number,
and have the booth automatically return all the coins,
forcing us to start over.
Something similar happens
with this metro ticket renewal system.
(MALE VOICE) Operation cancelled.
(ALEJANDRO) The user took a little longer
to insert the monthly pass they wished to renew,
so the system timed out and restarted the process.
Systems should give us enough time to complete our actions,
or, in other words, they should offer an alternative mode
to complete a function according to the user's time constraints.
They should also give users sufficient time
to read all the displayed information.
In conclusion, we have seen in this video
the important relationship between system operation
and the perception of the information it produces,
as well as an understanding of how it works overall.
We have also looked at accessibility requirements
related to operating all available functions
in a reasonable amount of time.
Other aspects of accessibility concerning system operation,
such as avoiding accidental control activation,
recovering from errors, and using a product efficiently,
will be addressed in a future video.