With no explanation, label each line with "O", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport", "building-hospital" or "building-hotel" preceded by ":".
Further
improvements
resulted
from
the
introduction
of
electronic
control
systems
,
which
permitted
the
use
of
increasingly
lighter
and
more
powerful
motors
that
could
be
fitted
inside
the
bogies
(
standardizing
from
the
1990s
onwards
on
asynchronous
three-phase
motors
,
fed
through
GTO-inverters
)
.
Further:O
improvements:O
resulted:O
from:O
the:O
introduction:O
of:O
electronic:O
control:O
systems:O
,:O
which:O
permitted:O
the:O
use:O
of:O
increasingly:O
lighter:O
and:O
more:O
powerful:O
motors:O
that:O
could:O
be:O
fitted:O
inside:O
the:O
bogies:O
(:O
standardizing:O
from:O
the:O
1990s:O
onwards:O
on:O
asynchronous:O
three-phase:O
motors:O
,:O
fed:O
through:O
GTO-inverters:O
):O
.:O