Information Technology Reference
In-Depth Information
2.
Data coherency
. Because we are addressing the service com-
position problem from the perspective of data, the composite
process should represent the data relations in the given service
portfolio.
3. Well-structuredness and conflict-freeness are favorable propert-
ies of business processes. We also require the solution to be
acyclic because a cyclic structure represents the iterative proc-
essing of the same type of data. Therefore, for computational
simplicity, we generate acyclic solutions, but in an execution
phase, the process can be cyclic.
First, we define the concept of a reduced service net before we
outline the solution steps.
Definition 3.7. (Reduced Service Net, RSN)
A reduced service net
N
R
¼ð
P
R
;
T
R
;
F
R
Þ
of service net
N
S
¼
(
P
,
T
,
F
) with respect to input data
type
i
and output data type
o
,or
N
R
ð
N
S
;
i
;
o
Þ
, is a subgraph of
N
S
, s.t.,
8
n
2
P
[
T
,
n
2
P
R
[
T
R
if in
N
S
,
R
(
i,n
)
¼R
(
n,o
)
¼
true
.
Remarks:
When
N
S
is reduced to
N
R
, any operations, data mediations,
and data types that are not on a path from data type
i
to data type
o
are
eliminated.We reduce a servicenet inorder to remove the unrelatedparts,
and the reduction process can be done by slightly modifying the graph
traverse algorithm [89].
Now, we can generate a feasible solution.
Input:
I
!
O
.
Output:
An AWSP, data-coherent
N
, which is a subgraph of service net
N
S
, with
i
as its input and
o
as its output, and contains no conflict place.
Step 1
. Construct a service net
N
S
given a service portfolio and data
mediations in both business and service domains. The method is
given in Definition 3.3.
Step 2
. Derive a reduced service net
N
R
from
N
S
.
