<s>
Janus	B-General_Concept
Recognition	I-General_Concept
Toolkit	I-General_Concept
(	O
JRTk	B-General_Concept
)	O
,	O
sometimes	O
referred	O
to	O
as	O
Janus	O
,	O
is	O
a	O
general	O
purpose	O
speech	O
recognition	O
toolkit	O
developed	O
and	O
maintained	O
by	O
the	O
Interactive	O
Systems	O
Laboratories	O
at	O
Carnegie	O
Mellon	O
University	O
and	O
Karlsruhe	O
Institute	O
of	O
Technology	O
.	O
</s>
<s>
The	O
JRTk	B-General_Concept
provides	O
a	O
flexible	O
Tcl/Tk	O
script	O
based	O
environment	O
which	O
enables	O
researchers	O
to	O
build	O
state-of-the-art	O
speech	O
recognizers	O
and	O
allows	O
them	O
to	O
develop	O
,	O
implement	O
,	O
and	O
evaluate	O
new	O
methods	O
.	O
</s>
<s>
Since	O
version	O
5	O
JRTk	B-General_Concept
features	O
the	O
IBIS	O
decoder	O
,	O
a	O
one-pass	O
decoder	O
that	O
is	O
based	O
on	O
a	O
re-entrant	O
single	O
pronunciation	O
prefix	O
tree	O
and	O
makes	O
use	O
of	O
the	O
concept	O
of	O
linguistic	O
context	O
polymorphism	O
.	O
</s>
<s>
JRTk	B-General_Concept
utilizes	O
the	O
concept	O
of	O
Hidden	O
Markov	O
Models	O
(	O
HMMs	O
)	O
for	O
acoustic	O
modeling	O
and	O
offers	O
many	O
state-of-the-art	O
techniques	O
for	O
acoustic	O
pre-processing	O
,	O
acoustic	O
model	O
training	O
,	O
and	O
speech	O
decoding	O
.	O
</s>
<s>
JRTk	B-General_Concept
has	O
been	O
used	O
by	O
the	O
Interactive	O
System	O
Labs	O
in	O
many	O
projects	O
for	O
speech	O
recognition	O
,	O
such	O
as	O
:	O
</s>
