
A Service Selection Problem with Dynamic Data Flows ... 111
FIGURE 4.11: Non-optimal example of a workflow with selected services
and data distribution.
As previously, d
in
ij
and d
out
ij
are assumed to be the sizes of input data and
size of the data produced by service s
ij
bound with d
out
ij
= f
t
i
(d
in
ij
). Function
f
t
i
is related to the task, not the service, since all services executing the task
must take the same input and return same output data. d
i
denotes the size
of data processed by task t
i
. Variable d
ij kl
denotes the size of data to be sent
from service s
ij
to service s
kl
. Then the required constraints on these variables
would include:
d
i
=
X
j
d
in
ij
(4.24)
d