Information Technology Reference
In-Depth Information
27.
flag
¼ true
;
28.
Exit
the
while
loop;
29.
end if
30.
end if
31.
end while
32.
end if
33.
if
flag
¼ true then
34.
for
i
¼
1to
n
do
35.
Draw a connector from the decision node to
n
pi
, set a guard
along this new connector with the condition
C
i
and then
delete the original connector pointed to it;
36.
end for
37.
Introduce a merge node
n
M
into the diagram, draw a connector
from action nodes
n
p
1
,
n
p
2
,
...
, and
n
pn
to it respectively;
and compute the corresponding state
S
M
of
n
M
;
38.
NS
¼
NS
f
n
p
1
;
n
p
2
; ...;
n
pn
g[f
n
M
g
;
39.
else
40.
The conditional branch is failed. Delete the related nodes;
41.
Exit
.
end if
43.
end if
42.
In the reasoning process, once the services mentioned in the user
preference (i.e.,
w
1
;
w
n
in PPMC) appear, we will examine
whether the truth value of condition formula
Cond
can be acquired and
prepare to introduce a branch structure into the diagram. We need to check
three cases as follows, which are processed similarly to those in PPCE.
In the first case,
Cond
can be evaluated under the current state
S
0
.In
this case, we can introduce a decision node into the diagram directly,
whose input comes from the action
n
0
(which is being processed in SCP).
In the second case,
Cond
cannot be evaluated under
S
0
.However,in
the set of services
V
(
S
0
) that can be executed currently, there is a service
such that the state obtained after executing it can result in the truth value
of
Cond
. Under this circumstance, we introduce a decision node after
the action corresponding to the service.
Third, if none of the aforementioned cases is satisfied, we continue
the reasoning process based on the action set
NS
temp
which corresponds
to the invocable service set
V
(
S
0
), till there exists an action whose state
can result in the truth value of
Cond
. Here, the reasoning process is
similar to the one in SCP.
w
2
; ...;
