<s>
The	O
Knowledge	B-Application
Based	I-Application
Software	I-Application
Assistant	I-Application
(	O
KBSA	O
)	O
was	O
a	O
research	O
program	O
funded	O
by	O
the	O
United	O
States	O
Air	O
Force	O
.	O
</s>
<s>
The	O
goal	O
of	O
the	O
program	O
was	O
to	O
apply	O
concepts	O
from	O
artificial	B-Application
intelligence	I-Application
to	O
the	O
problem	O
of	O
designing	O
and	O
implementing	O
computer	B-Application
software	I-Application
.	O
</s>
<s>
The	O
air	O
force	O
hoped	O
to	O
be	O
able	O
to	O
generate	O
the	B-Application
software	I-Application
to	O
control	O
weapons	O
systems	O
and	O
other	O
command	O
and	O
control	O
systems	O
using	O
this	O
method	O
.	O
</s>
<s>
As	O
software	O
was	O
becoming	O
ever	O
more	O
critical	O
to	O
USAF	O
weapons	O
systems	O
it	O
was	O
realized	O
that	O
improving	O
the	O
quality	O
and	O
productivity	O
of	O
the	B-Application
software	I-Application
development	O
process	O
could	O
have	O
significant	O
benefits	O
for	O
the	O
military	O
,	O
as	O
well	O
as	O
for	O
information	B-General_Concept
technology	I-General_Concept
in	O
other	O
major	O
US	O
industries	O
.	O
</s>
<s>
In	O
the	O
early	O
1980s	O
the	O
United	O
States	O
Air	O
Force	O
realized	O
that	O
they	O
had	O
received	O
significant	O
benefits	O
from	O
applying	O
artificial	B-Application
intelligence	I-Application
technologies	O
to	O
solving	B-Application
expert	I-Application
problems	I-Application
such	O
as	O
the	O
diagnosis	O
of	O
faults	O
in	O
aircraft	O
.	O
</s>
<s>
The	O
air	O
force	O
commissioned	O
a	O
group	O
of	O
researchers	O
from	O
the	B-Application
artificial	I-Application
intelligence	I-Application
and	O
formal	B-Architecture
methods	I-Architecture
communities	O
to	O
develop	O
a	O
report	O
on	O
how	O
such	O
technologies	O
might	O
be	O
used	O
to	O
aid	O
in	O
the	O
more	O
general	O
problem	O
of	O
software	O
development	O
.	O
</s>
<s>
Rather	O
than	O
define	O
specifications	O
with	O
diagrams	O
and	O
manually	O
transform	O
them	O
to	O
code	O
as	O
was	O
the	O
current	O
process	O
,	O
the	O
Knowledge	B-Application
Based	I-Application
Software	I-Application
Assistant	I-Application
(	O
KBSA	O
)	O
vision	O
was	O
to	O
define	O
specifications	O
in	O
very	O
high	O
level	O
languages	O
and	O
then	O
to	O
use	O
transformation	O
rules	O
to	O
gradually	O
refine	O
the	O
specification	O
into	O
efficient	O
code	O
on	O
heterogeneous	O
platforms	O
.	O
</s>
<s>
Each	O
step	O
in	O
the	O
design	O
and	O
refinement	O
of	O
the	O
system	O
would	O
be	O
recorded	O
as	O
part	O
of	O
an	O
integrated	O
repository	B-General_Concept
.	O
</s>
<s>
Also	O
,	O
in	O
these	O
later	O
stages	O
the	O
emphasis	O
shifted	O
from	O
a	O
pure	O
KBSA	O
approach	O
to	O
more	O
general	O
questions	O
of	O
how	O
to	O
use	O
knowledge-based	O
technology	O
to	O
supplement	O
and	O
augment	O
existing	O
and	O
future	O
computer-aided	B-Application
software	I-Application
engineering	I-Application
(	O
CASE	O
)	O
tools	O
.	O
</s>
<s>
In	O
these	O
later	O
stages	O
there	O
was	O
significant	O
interaction	O
between	O
the	O
KBSA	O
community	O
and	O
the	O
object-oriented	B-Language
and	O
software	O
engineering	O
communities	O
.	O
</s>
<s>
The	O
name	O
change	O
reflected	O
the	O
different	O
research	O
goal	O
,	O
no	O
longer	O
to	O
create	O
a	O
totally	O
new	O
all	O
encompassing	O
tool	O
that	O
would	O
cover	O
the	O
complete	O
software	O
life	B-General_Concept
cycle	I-General_Concept
but	O
to	O
gradually	O
work	O
knowledge-based	O
technology	O
into	O
existing	O
tools	O
.	O
</s>
<s>
The	O
transformation	O
rules	O
that	O
KBSA	O
used	O
were	O
different	O
than	O
traditional	O
rules	O
for	O
expert	B-Application
systems	I-Application
.	O
</s>
<s>
Evolution	O
transformations	O
were	O
developed	O
at	O
approximately	O
the	O
same	O
time	O
as	O
the	O
emergence	O
of	O
the	B-Application
software	I-Application
patterns	O
community	O
and	O
the	O
two	O
groups	O
shared	O
concepts	O
and	O
technology	O
.	O
</s>
<s>
Evolution	O
transformations	O
were	O
essentially	O
what	O
is	O
known	O
as	O
refactoring	O
in	O
the	O
object-oriented	B-Language
software	O
patterns	O
community	O
.	O
</s>
<s>
were	O
represented	O
as	O
objects	O
in	O
a	O
knowledge-based	O
repository	B-General_Concept
.	O
</s>
<s>
The	O
requirement	O
was	O
for	O
a	O
knowledge	O
representation	O
framework	O
that	O
could	O
support	O
the	O
entire	O
life	B-General_Concept
cycle	I-General_Concept
:	O
requirements	O
,	O
specification	O
,	O
and	O
code	O
as	O
well	O
as	O
the	B-Application
software	I-Application
process	O
itself	O
.	O
</s>
<s>
These	O
early	O
knowledge-base	O
frameworks	O
were	O
developed	O
primarily	O
by	O
ISI	O
and	O
Kestrel	O
building	O
on	O
top	O
of	O
Lisp	B-Language
and	O
Lisp	B-Operating_System
machine	I-Operating_System
environments	O
.	O
</s>
<s>
With	O
the	O
growing	O
concern	O
of	O
the	O
Y2K	B-Error_Name
problem	I-Error_Name
reverse	O
engineering	O
was	O
a	O
major	O
business	O
concern	O
for	O
many	O
large	O
US	O
corporations	O
and	O
it	O
was	O
a	O
focus	O
area	O
for	O
KBSA	O
research	O
in	O
the	O
1990s	O
.	O
</s>
<s>
There	O
was	O
significant	O
interaction	O
between	O
the	O
KBSA	O
communities	O
and	O
the	O
Frame	O
language	O
and	O
object-oriented	B-Language
communities	O
.	O
</s>
<s>
The	O
early	O
KBSA	O
knowledge-bases	O
were	O
implemented	O
in	O
object-based	B-Application
languages	I-Application
rather	O
than	O
object-oriented	B-Language
.	O
</s>
<s>
KBSA	O
took	O
a	O
different	O
approach	O
than	O
traditional	O
expert	B-Application
systems	I-Application
when	O
it	O
came	O
to	O
how	O
to	O
solve	O
problems	O
and	O
work	O
with	O
users	O
.	O
</s>
<s>
In	O
the	O
traditional	O
expert	B-Application
system	I-Application
approach	O
the	O
user	O
answers	O
a	O
series	O
of	O
interactive	O
questions	O
and	O
the	O
system	O
provides	O
a	O
solution	O
.	O
</s>
<s>
Where	O
as	O
an	O
expert	B-Application
system	I-Application
tried	O
to	O
,	O
to	O
some	O
extent	O
replace	O
and	O
remove	O
the	O
need	O
for	O
the	O
expert	O
the	O
intelligent	O
assistant	O
approach	O
in	O
KBSA	O
sought	O
to	O
re-invent	O
the	O
process	O
with	O
technology	O
.	O
</s>
<s>
An	O
example	O
of	O
the	O
collaboration	O
between	O
the	O
object-oriented	B-Language
community	O
and	O
KBSA	O
was	O
the	O
architecture	O
used	O
for	O
KBSA	O
user	O
interfaces	O
.	O
</s>
