<s>
In	O
the	O
fields	O
of	O
physical	O
security	O
and	O
information	O
security	O
,	O
the	O
high-water	B-General_Concept
mark	I-General_Concept
for	O
access	O
control	O
was	O
introduced	O
by	O
Clark	O
Weissmann	O
in	O
1969	O
.	O
</s>
<s>
Under	O
high-water	B-General_Concept
mark	I-General_Concept
,	O
any	O
object	O
less	O
than	O
the	O
user	O
's	O
security	O
level	O
can	O
be	O
opened	O
,	O
but	O
the	O
object	O
is	O
relabeled	O
to	O
reflect	O
the	O
highest	O
security	O
level	O
currently	O
open	O
,	O
hence	O
the	O
name	O
.	O
</s>
<s>
The	O
practical	O
effect	O
of	O
the	O
high-water	B-General_Concept
mark	I-General_Concept
was	O
a	O
gradual	O
movement	O
of	O
all	O
objects	O
towards	O
the	O
highest	O
security	O
level	O
in	O
the	O
system	O
.	O
</s>
