<s>
SHYSTER	B-Application
is	O
a	O
legal	B-Application
expert	I-Application
system	I-Application
developed	O
at	O
the	O
Australian	O
National	O
University	O
in	O
Canberra	O
in	O
1993	O
.	O
</s>
<s>
SHYSTER	B-Application
emphasises	O
its	O
pragmatic	O
approach	O
,	O
and	O
posits	O
that	O
a	O
legal	B-Application
expert	I-Application
system	I-Application
need	O
not	O
be	O
based	O
upon	O
a	O
complex	O
model	O
of	O
legal	O
reasoning	O
in	O
order	O
to	O
produce	O
useful	O
advice	O
.	O
</s>
<s>
Although	O
SHYSTER	B-Application
attempts	O
to	O
model	O
the	O
way	O
in	O
which	O
lawyers	O
argue	O
with	O
cases	O
,	O
it	O
does	O
not	O
attempt	O
to	O
model	O
the	O
way	O
in	O
which	O
lawyers	O
decide	O
which	O
cases	O
to	O
use	O
in	O
those	O
arguments	O
.	O
</s>
<s>
SHYSTER	B-Application
is	O
of	O
a	O
general	O
design	O
,	O
permitting	O
its	O
operation	O
in	O
different	O
legal	O
domains	O
.	O
</s>
<s>
It	O
was	O
designed	O
to	O
provide	O
advice	O
in	O
areas	O
of	O
case	O
law	O
that	O
have	O
been	O
specified	O
by	O
a	O
legal	O
expert	O
using	O
a	O
bespoke	O
specification	B-Application
language	I-Application
.	O
</s>
<s>
It	O
derives	O
its	O
name	O
from	O
Shyster	B-Application
:	O
a	O
slang	O
word	O
for	O
someone	O
who	O
acts	O
in	O
a	O
disreputable	O
,	O
unethical	O
,	O
or	O
unscrupulous	O
way	O
,	O
especially	O
in	O
the	O
practice	O
of	O
law	O
and	O
politics	O
.	O
</s>
<s>
SHYSTER	B-Application
is	O
a	O
specific	O
example	O
of	O
a	O
general	O
category	O
of	O
legal	B-Application
expert	I-Application
systems	I-Application
,	O
broadly	O
defined	O
as	O
systems	O
that	O
make	O
use	O
of	O
artificial	O
intelligence	O
(	O
AI	O
)	O
techniques	O
to	O
solve	O
legal	O
problems	O
.	O
</s>
<s>
SHYSTER	B-Application
belongs	O
to	O
the	O
latter	O
category	O
of	O
legal	O
analysis	O
systems	O
.	O
</s>
<s>
Legal	O
analysis	O
systems	O
can	O
be	O
further	O
subdivided	O
into	O
two	O
categories	O
:	O
judgment	O
machines	O
and	O
legal	B-Application
expert	I-Application
systems	I-Application
.	O
</s>
<s>
SHYSTER	B-Application
again	O
belongs	O
to	O
the	O
latter	O
category	O
of	O
legal	B-Application
expert	I-Application
systems	I-Application
.	O
</s>
<s>
A	O
legal	B-Application
expert	I-Application
system	I-Application
,	O
as	O
Popple	O
uses	O
the	O
term	O
,	O
is	O
a	O
system	O
capable	O
of	O
performing	O
at	O
a	O
level	O
expected	O
of	O
a	O
lawyer	O
:	O
“	O
AI	O
systems	O
which	O
merely	O
assist	O
a	O
lawyer	O
in	O
coming	O
to	O
legal	O
conclusions	O
or	O
preparing	O
legal	O
arguments	O
are	O
not	O
here	O
considered	O
to	O
be	O
legal	B-Application
expert	I-Application
systems	I-Application
;	O
a	O
legal	B-Application
expert	I-Application
system	I-Application
must	O
exhibit	O
some	O
legal	O
expertise	O
itself.	O
"	O
</s>
<s>
Designed	O
to	O
operate	O
in	O
more	O
than	O
one	O
legal	O
domain	O
,	O
and	O
be	O
of	O
specific	O
use	O
to	O
the	O
common	O
law	O
of	O
Australia	O
,	O
SHYSTER	B-Application
accounts	O
for	O
statute	O
law	O
,	O
case	O
law	O
,	O
and	O
the	O
doctrine	O
of	O
precedent	O
in	O
areas	O
of	O
private	O
law	O
.	O
</s>
<s>
Users	O
of	O
SHYSTER	B-Application
therefore	O
require	O
some	O
legal	O
expertise	O
.	O
</s>
<s>
Richard	O
Susskind	O
argues	O
that	O
“	O
jurisprudence	O
can	O
and	O
ought	O
to	O
supply	O
the	O
models	O
of	O
law	O
and	O
legal	O
reasoning	O
that	O
are	O
required	O
for	O
computerized	O
 [ sic ] 	O
implementation	O
in	O
the	O
process	O
of	O
building	O
all	O
expert	O
systems	O
in	O
law.	O
”	O
Popple	O
,	O
however	O
,	O
believes	O
jurisprudence	O
is	O
of	O
limited	O
value	O
to	O
developers	O
of	O
legal	B-Application
expert	I-Application
systems	I-Application
.	O
</s>
<s>
The	O
fact	O
that	O
many	O
lawyers	O
have	O
mastered	O
the	O
process	O
of	O
legal	O
reasoning	O
,	O
without	O
having	O
been	O
immersed	O
in	O
jurisprudence	O
,	O
suggests	O
that	O
it	O
may	O
indeed	O
be	O
possible	O
to	O
develop	O
legal	B-Application
expert	I-Application
systems	I-Application
of	O
good	O
quality	O
without	O
jurisprudential	O
insight	O
.	O
</s>
<s>
As	O
a	O
pragmatic	O
legal	B-Application
expert	I-Application
system	I-Application
SHYSTER	B-Application
is	O
the	O
embodiment	O
of	O
this	O
belief	O
.	O
</s>
<s>
A	O
further	O
example	O
of	O
SHYSTER	B-Application
’s	O
pragmatism	O
is	O
its	O
simple	O
knowledge	O
representation	O
structure	O
.	O
</s>
<s>
This	O
structure	O
was	O
designed	O
to	O
facilitate	O
specification	O
of	O
different	O
areas	O
of	O
case	O
law	O
using	O
a	O
specification	B-Application
language	I-Application
.	O
</s>
<s>
SHYSTER	B-Application
weights	O
its	O
attributes	O
and	O
checks	O
for	O
dependence	O
between	O
them	O
.	O
</s>
<s>
In	O
order	O
to	O
choose	O
cases	O
upon	O
which	O
to	O
construct	O
its	O
opinions	O
,	O
SHYSTER	B-Application
calculates	O
distances	O
between	O
cases	O
and	O
uses	O
these	O
distances	O
to	O
determine	O
which	O
of	O
the	O
leading	O
cases	O
are	O
nearest	O
to	O
the	O
instant	O
case	O
.	O
</s>
<s>
To	O
this	O
end	O
SHYSTER	B-Application
can	O
be	O
seen	O
to	O
adopt	O
and	O
expand	O
upon	O
nearest	B-Algorithm
neighbor	I-Algorithm
search	I-Algorithm
methods	O
used	O
in	O
pattern	O
recognition	O
.	O
</s>
<s>
SHYSTER	B-Application
then	O
uses	O
information	O
about	O
these	O
nearest	O
cases	O
to	O
construct	O
a	O
report	O
.	O
</s>
<s>
The	O
report	O
that	O
SHYSTER	B-Application
generates	O
makes	O
a	O
prediction	O
and	O
justifies	O
that	O
prediction	O
by	O
reference	O
only	O
to	O
cases	O
and	O
their	O
similarities	O
and	O
differences	O
:	O
the	O
calculations	O
that	O
SHYSTER	B-Application
performs	O
in	O
coming	O
to	O
its	O
opinion	O
do	O
not	O
appear	O
in	O
that	O
opinion	O
.	O
</s>
<s>
Safeguards	O
are	O
employed	O
to	O
warn	O
users	O
if	O
SHYSTER	B-Application
doubts	O
the	O
veracity	O
of	O
its	O
advice	O
.	O
</s>
<s>
SHYSTER	B-Application
was	O
tested	O
in	O
four	O
different	O
and	O
disparate	O
areas	O
of	O
case	O
law	O
.	O
</s>
<s>
SHYSTER	B-Application
was	O
evaluated	O
under	O
five	O
headings	O
:	O
its	O
usefulness	O
,	O
its	O
generality	O
,	O
the	O
quality	O
of	O
its	O
advice	O
,	O
its	O
limitations	O
,	O
and	O
possible	O
enhancements	O
that	O
could	O
be	O
made	O
to	O
it	O
.	O
</s>
<s>
Appreciating	O
the	O
difficulties	O
encountered	O
by	O
legal	B-Application
expert	I-Application
systems	I-Application
developers	O
in	O
adequately	O
representing	O
legal	O
knowledge	O
can	O
assist	O
in	O
appreciating	O
the	O
shortcomings	O
of	O
digital	O
rights	O
management	O
technologies	O
.	O
</s>
<s>
To	O
this	O
end	O
SHYSTER	B-Application
's	O
attempt	O
to	O
model	O
“	O
authorization	O
[sic]”	O
in	O
the	O
Copyright	O
Act	O
can	O
be	O
viewed	O
as	O
pioneering	O
work	O
in	O
this	O
field	O
.	O
</s>
<s>
When	O
applied	O
to	O
one	O
case	O
concerning	O
compact	B-Device
cassettes	I-Device
,	O
SHYSTER	B-Application
successfully	O
agreed	O
that	O
Amstrad	O
did	O
not	O
authorise	O
the	O
infringement	O
.	O
</s>
<s>
Popple	O
highlighted	O
the	O
most	O
obvious	O
avenue	O
of	O
future	O
research	O
using	O
SHYSTER	B-Application
as	O
the	O
development	O
of	O
a	O
rule-based	O
system	O
,	O
and	O
the	O
linking	O
together	O
of	O
that	O
rule-based	O
system	O
with	O
the	O
existing	O
case-based	O
system	O
to	O
form	O
a	O
hybrid	O
system	O
.	O
</s>
<s>
This	O
intention	O
was	O
eventually	O
realised	O
by	O
Thomas	O
O’Callaghan	O
,	O
the	O
creator	O
of	O
SHYSTER-MYCIN	O
:	O
a	O
hybrid	O
legal	B-Application
expert	I-Application
system	I-Application
first	O
presented	O
at	O
ICAIL	O
'	O
03	O
,	O
24	O
–	O
28	O
June	O
2003	O
in	O
Edinburgh	O
,	O
Scotland	O
.	O
</s>
<s>
MYCIN	O
is	O
an	O
existing	O
medical	O
expert	O
system	O
,	O
which	O
was	O
adapted	O
for	O
use	O
with	O
SHYSTER	B-Application
.	O
</s>
<s>
MYCIN	O
’s	O
controversial	O
“	O
certainty	O
factor	O
”	O
is	O
not	O
used	O
in	O
SHYSTER-MYCIN	O
.	O
</s>
<s>
This	O
hybrid	O
system	O
enables	O
the	O
case-based	O
system	O
(	O
SHYSTER	B-Application
)	O
to	O
determine	O
open	O
textured	O
concepts	O
when	O
required	O
by	O
the	O
rule-based	O
system	O
(	O
MYCIN	O
)	O
.	O
</s>
<s>
The	O
ultimate	O
conclusion	O
of	O
this	O
joint	O
endeavour	O
is	O
that	O
a	O
hybrid	O
approach	O
is	O
preferred	O
in	O
the	O
creation	O
of	O
legal	B-Application
expert	I-Application
systems	I-Application
where	O
“	O
it	O
is	O
appropriate	O
to	O
use	O
rule-based	O
reasoning	O
when	O
dealing	O
with	O
statutes	O
,	O
and	O
…	O
case-based	O
reasoning	O
when	O
dealing	O
with	O
cases	O
”	O
.	O
</s>
