<s>
In	O
automata	B-Application
theory	I-Application
,	O
an	O
alternating	B-Application
timed	I-Application
automaton	I-Application
(	O
ATA	O
)	O
is	O
a	O
mix	O
of	O
both	O
timed	B-Application
automaton	I-Application
and	O
alternating	B-General_Concept
finite	I-General_Concept
automaton	I-General_Concept
.	O
</s>
<s>
ATAs	O
are	O
more	O
expressive	O
than	O
timed	B-Application
automaton	I-Application
.	O
</s>
<s>
one	O
clock	O
alternating	B-Application
timed	I-Application
automaton	I-Application
(	O
OCATA	O
)	O
is	O
the	O
restriction	O
of	O
ATA	O
allowing	O
the	O
use	O
of	O
a	O
single	O
clock	O
.	O
</s>
<s>
An	O
alternating	B-Application
timed	I-Application
automaton	I-Application
is	O
defined	O
as	O
a	O
timed	B-Application
automaton	I-Application
,	O
where	O
the	O
transitions	O
are	O
more	O
complex	O
.	O
</s>
<s>
For	O
each	O
letter	O
and	O
location	O
,	O
let	O
be	O
a	O
set	O
of	O
clock	O
constraints	O
such	O
that	O
their	O
zones	O
partition	O
,	O
with	O
the	O
number	O
of	O
clocks	B-Application
.	O
</s>
<s>
Formally	O
,	O
an	O
alternating	B-Application
timed	I-Application
automaton	I-Application
is	O
a	O
tuple	O
that	O
consists	O
of	O
the	O
following	O
components	O
:	O
</s>
<s>
is	O
a	O
finite	O
set	O
called	O
the	O
clocks	B-Application
of	O
.	O
</s>
<s>
Any	O
Boolean	O
expression	O
can	O
be	O
rewritten	O
into	O
an	O
equivalent	O
expression	O
in	O
disjunctive	B-Application
normal	I-Application
form	I-Application
.	O
</s>
<s>
The	O
tail	O
is	O
labelled	O
by	O
the	O
letter	O
and	O
each	O
head	O
is	O
labelled	O
by	O
the	O
set	O
of	O
clocks	B-Application
it	O
resets	O
.	O
</s>
<s>
We	O
now	O
define	O
a	O
run	O
of	O
an	O
alternating	B-Application
timed	I-Application
automaton	I-Application
over	O
a	O
timed	O
word	O
.	O
</s>
<s>
Without	O
loss	O
of	O
generality	O
,	O
let	O
us	O
assume	O
that	O
is	O
in	O
disjunctive	B-Application
normal	I-Application
form	I-Application
,	O
i.e.	O
</s>
<s>
The	O
definition	O
of	O
an	O
accepting	O
run	O
is	O
the	O
same	O
than	O
for	O
timed	B-Application
automata	I-Application
.	O
</s>
<s>
A	O
one	O
clock	O
alternating	B-Application
timed	I-Application
automaton	I-Application
(	O
OCATA	O
)	O
is	O
an	O
alternating	B-Application
timed	I-Application
automaton	I-Application
using	O
a	O
single	O
clock	O
.	O
</s>
<s>
In	O
this	O
alternating	B-Application
timed	I-Application
automaton	I-Application
,	O
two	O
branches	O
are	O
started	O
.	O
</s>
