3.3 Composing Service Bundles
After this customer dialogue, we first match the set
of consequences desired by the customer to conse-
quences defined from a supplier’s perspective. We can
do this because (cf. section 2.2) the concept and the-
ory of consequences provides the bridging connection
between the customer and supply sides for the match-
making process. The computational result of this con-
sequence matching is a subset of supply-side conse-
quences that, together with the prioritization scores
provided by the customer, can be used to reason about
(1) finding (composing) service bundles and (2) rank-
ing service bundles according to prioritization scores.
We first search for those service bundles that can
satisfy all ‘must-have’ consequences. To find these
bundles, we search for: (1) the supplier-specific ser-
vice properties jointly satisfying the consequence; (2)
supplier-specific resources that contain these prop-
erties; and finally (3) bundles that contain these re-
sources. Depending on the scale type, we evaluate on
the basis of the consequences in hand whether a bun-
dle can satisfy all consequences from nominal scales
that are marked as must-haves, and contains at least
one consequence from each ordinal scale marked as a
must-have.
Case Example. From the previous step, we have
the functional consequence ‘send and receive text’
with importance ‘10’ and four quality consequences:
‘small mailbox’ and ‘large mailbox’ from the scale
‘mailbox size’ (the latter with an importance rank-
ing of 3) and ‘local’ (importance 1) and ‘use at any
site with connectivity’ (importance 8) from the scale
‘access type’. These are matched to all supply- side
consequences, see Figure 5. Next, we find the bun-
dles that satisfy the must-have consequence ‘send
and receive text’. For this, we first find all possible
sets of supplier-specific service properties satisfying
this consequence. An example in this case could be
‘POP3’ or ‘upspeed= 128 kbps’. These service prop-
erties belong to the resources ‘email access (KPN)’
and ‘IP access KPN’ which are attached to two ser-
vice ports of the bundle ‘KPN email bundle’ (Fig-
ure 5). ‘KPN email bundle’ is therefore satisfying all
must-have consequences and hence can be considered
further, as is the case with all other bundles shown in
this figure since they can all provide the consequence
‘send and receive text’.
3.4 Ranking Service Bundles
The next step is to rank the found relevant bundles.
For this, we convert the best-to-worse ordinal rank-
ing of consequences to a numerical ranking, by using
the Rank-Order Centroid method (ROC, (Barron and
Barrett, 1996)). Additionally, we need to provide a
score to indicate whether a consequence defined on
a nominal scale is present in a service bundle. This
score we provide in a binary way: if a consequence is
present in a bundle it scores 1, else 0.
Now that we have numerical values to express
consequence scores and as well as importance scores
from the customer, we calculate a ranking score for
each service bundle by using the multi-attribute scor-
ing formula SB
i
=
∑
n
j= 1
w
j
10
v
ij
, where SB
i
is the rank-
ing score for service bundle i, w
j
is the importance
ranking of consequence j as provided by the cus-
tomer, and v
ij
is the numerical value for the conse-
quence j of service bundle i. After having calcu-
lated to what extent a service bundle fits with cus-
tomer preferences, we find for each bundle additional
consequences that a customer also must acquire. For
each service bundle we then obtain service ports ad-
ditional to those already found by reviewing their ser-
vice interface. Taking these additional service ports
as a starting point we then derive consequences by
using the process of finding service ports based upon
consequences described before, only then in reverse.
Case Example. To rank the bundles, we calculate
a score for the consequences defined on the ordinal
‘mailbox size’ scale. Using ROC, we derive the score
0.75 for the consequence ‘large mailbox’ and 0.25 for
the consequence ‘small mailbox’. Now, we calculate
a ranking score for each of the possible bundles by us-
ing the above multi-attribute formula, and then com-
pute its full set of consequences. For example, in the
case of the KPN g-mail bundle, we find two additional
service ports: one containing the resource ‘fee’ with
a service property of ‘EUR 20’, the other contain-
ing the resource ‘lock-in’ with a service property of
‘12 months’. From this, we derive the consequences
‘IP-access fee’ and ‘lock-in’. With the consequences
already found, we finally arrive at the following full
set of consequences for the KPN g-mail bundle: send
and receive text, large mailbox, access mail at any site
with connectivity, IP access fee, lock-in.
3.5 Trade-off Decision Making
Next, we present the found bundles in a ranking to the
customer, together with a specification of the conse-
quences received from a bundle and the consequences
s/he has to give up to acquire a bundle. Furthermore,
the tool shows a specification in terms of a pricing
model (cf. (de Miranda, 2006)). The customer has
the option to either select a bundle from the ranking
or, in case s/he finds the costs incurred for the bundles
too high, to go back to the step ‘choose consequences’
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MODELS
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