<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Archiving and Interchange DTD v1.0 20120330//EN" "JATS-archivearticle1.dtd">
<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Generating Value Models using Skeletal Design Techniques</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Ivan S. Razo-Zapata</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Ania Chmielowiec</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Jaap Gordijn</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Maarten van Steen</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Pieter De Leenheer</string-name>
          <email>pgm.de.leenheer@few.vu.nl</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>VU University Amsterdam De Boelelaan 1081 1081 HV</institution>
          ,
          <addr-line>Amsterdam</addr-line>
          ,
          <country country="NL">The Netherlands</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2010</year>
      </pub-date>
      <fpage>91</fpage>
      <lpage>105</lpage>
      <abstract>
        <p>This paper presents a novel approach to automatically generate e3value instance models, based on skeletal design techniques. The approach has three phases. While the rst two phases are related to the generation of a value activity network based on a given value skeleton, the third phase matches the elements of the value network with the capabilities of service providers. The main objective of our approach is to re-use a set of value skeletons for covering an industry sector from which more business cases may be generated. Finally, we validated our approach in a realistic case study.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>Introduction</title>
      <p>
        Enterprises increasingly participate in networked value constellations [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. By
doing so, enterprises can jointly satisfy a more complex consumer need than they
could ever do on their own. Consider for instance the music industry, our case
study domain. If a person listens to music on the radio, apart from the radio
station, Intellectual Property Rights (IPR) societies will be needed to collect
money for the artists, song writers, producers and other IPR owners. All these
actors are part of a value constellation that is needed to listen to a music track
on the radio.
      </p>
      <p>
        In earlier work [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ], we proposed the e3value methodology to design value
constellations. In brief, e3value is a conceptual modelling approach, which is
used to describe a network of enterprises who exchange objects of value with
each other.
      </p>
      <p>The contribution of this paper is to lift e3value to the industry level, e.g. to
describe the music industry, rather than just a single business case, as e3value
normally is used for. To do so we present e3value skeletons. One of the most
important di erences between an e3value skeleton and a normal e3value business
case model is that a business case contains named, speci c, enterprises who
participate in the business case at hand, whereas a skeleton contains only the
set of activities to be performed for a business case.</p>
      <p>
        One of the purposes of an e3value skeleton is to easily generate many
variations of business cases, which can be presented to stakeholders for selection.
Moreover, since mass con guration of products is playing an important role
nowadays [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ], our long term ultimate goal is to automatically compose networked
value constellations, including the required business processes and IT support in
the form of web services. Such IT is then aligned with the business, since both
are designed in an integrated way.
      </p>
      <p>We refer to industry models as skeletons and to business case models as
instances. By using skeletal design techniques (Sect. 2.2), we derive e3value
instance models from a skeleton. For the music industry (case study description in
Sect. 3), we have developed various e3value instance models to study variations
of these models. Abstracted versions of these variations are captured in
skeleton models (Sect. 4.2). By using user input (Sect. 4.1) and con guration data
(Sect. 4.3), we generate e3value instance models (Sect. 5). Fig. 1 depicts this
general idea. Finally, Sect. 6 presents conclusions and future work.</p>
    </sec>
    <sec id="sec-2">
      <title>Value models and skeletal design</title>
      <sec id="sec-2-1">
        <title>Value models</title>
        <p>
          An e3value model depicts a network of enterprises creating, distributing, and
consuming objects of economic value [
          <xref ref-type="bibr" rid="ref4">4</xref>
          ]. The focus of the model is on what kind
of objects enterprises must exchange to each other in order to cover consumer
needs 1. Fig. 2 shows (at the bottom) the modelling constructs of e3value and
(on top) an educational example.
        </p>
        <p>
          The most important e3value constructs are as follows: Actors, such as a buyer
and seller, are economically independent entities (Fig. 2). Actors transfer value
objects (money, goods) by means of value transfers, which in turn connect value
ports. For value objects, some actor should be willing to pay, which is shown by
1 and not in HOW, this is the focus of a business process
a value interface. A value interface models the principle of economic reciprocity :
Only if you pay, you can obtain the goods and vice versa. Besides, actors perform
value activities, which create something of economic value. Finally, an e3value
model contains a dependency path, starting with a consumer need and ending
with a boundary element. Along the path are value transfers, value interfaces
and connection elements. The dependency path shows how many value transfers
are executed as a result of a consumer need. An elaborated formalisation of
e3value can be found in [
          <xref ref-type="bibr" rid="ref4">4</xref>
          ].
2.2
        </p>
      </sec>
      <sec id="sec-2-2">
        <title>Skeletal design</title>
        <p>
          Since we want to generate value models by means of value skeletons, it is useful
to take into account con guration design theory. According to Motta, a con
guration design problem does not exhibit complex spatial requirements and all
possible solutions adhere to a common solution template [
          <xref ref-type="bibr" rid="ref5">5</xref>
          ]. For this reason we
think the con guration of services, by using value models, adheres to a generic
template. Wielinga and Schreiber describe four main categories of con guration
design: assignment, scheduling, skeletal design and parametric design [
          <xref ref-type="bibr" rid="ref6">6</xref>
          ]. The
last two categories are related to our research.
        </p>
        <p>
          Parametric design is described as the process of assigning values to design
parameters not only satisfying needs and constraints but also following an
optimization criterion [
          <xref ref-type="bibr" rid="ref5">5</xref>
          ] 2. Skeletal design refers to a model-based mapping between
components and the assembly [
          <xref ref-type="bibr" rid="ref6">6</xref>
          ]. Because our solution is not considering
assigning values to a xed template but a model-based generation of new components,
our approach is more related to skeletal design.
        </p>
        <p>To sum up, our approach considers that the target artifact is modeled as a
set of elements and the solution implies generating elements based on a
common solution template matching the given design requirements and constraints
(Sect. 5).
3</p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>Case study: Clearing Intellectual Property Rights</title>
      <p>In the music industry, Intellectual Property Rights (IPR) are an important
concept. Neighboring rights are a kind of IPR, which have to be paid by users if
they earn money by playing music, or in other words, if they make music
public. Clearing such neighboring rights involves two steps: collecting fees from IPR
users, i.e. radio stations, bars, discotheques and others, and distributing these
fees to Right Owners, i.e. artists, song writers, producers. This process is usually
performed by IPR societies and is called clearing tracks. One of the IPR societies
designed to perform this activity in The Netherlands is SENA 3, our case study
partner which is also one of our stakeholders.</p>
      <p>
        Some results for modeling this case study have been already provided [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ],
however these results only address one of the multiple scenarios that can emerge
in the music industry, such as new actors performing less or more activities
because of market liberalization and new trends in the way of delivering music [
        <xref ref-type="bibr" rid="ref7 ref8">7,
8</xref>
        ]. One such a trend is that SENA, instead of clearing tracks based on play lists
of the top 30 radio statios (estimation), clears tracks based on the actual usage
(pay-per-play ).
      </p>
      <p>The e3value model depicted in Fig. 3 presents a pay-per-play solution for
background music. In this e3value model, IPR users are the starting point, as
they require to broadcast background music which is provided by background
music providers (BMP). A BMP can provide background music in di erent ways,
one of those is streaming (Value Transfer A). When providing streams, the BMP
must pay to IPR Societies which collect fees related with making a stream
available to the public (Value Transfer D-E). Here, the public refers to IPR users.</p>
      <p>IPR users have to also pay IPR Societies, as they make public the music also
to their customers. Although the BMP and IPR users pay to two IPR Societies,
it does not mean they pay twice for the same thing. Paying BUMA/Stemra 4
is because of the right that the composers, publishers and lyricists hold (Value
Transfer C), whereas paying SENA is related to the rights of the performing
2 Motta also mentions preferences, however at this stage they are not essential to nd
an optimal solution.
3 (Dutch: Stichting ter Exploitatie van Naburige Rechten, English: Foundation for</p>
      <p>Exploitation of Neighboring Rights)
4 BUMA is other IPR society, also working in The Netherlands
artists and producers (Value Transfer B). Indeed, Value Transfers A-E are
constraints imposed by law, since IPR societies are the responsable entitites for
collecting fees on behalf of IPR owners.</p>
      <p>Once IPR societies got IPR-user fees, they retain a small percentage of these
fees and the next step is to repartition the rest of the fees among Right Owners
(Value Transfer K-L). This set of Right Owners is mainly composed by Artists,
Producers, Music Publishers, Composers and Lyricists. Whereas SENA only
repartitions fees to Artists and Producers (Value Transfer F-G), BUMA/Stemra
does the same for Publishers, Composers and Lyricists (Value Transfer H-J).
Explosion Elements Due to the fact that tracks are usually performed by more
than one artist, SENA must transfer the collected fees to each artist involved,
consequently the value transfer F will occur more than one time per consumer
need. In order to allow that SENA contacts more artists, an explosion element
(EE #1) is added. Since the same holds for all the right owners, there are more
explosion elements for each of them (EE #2 - EE #5). An explosion element
models that the connected value transfers happen multiple times, rather than
just once per dependency path execution.</p>
      <p>In this scenario there are only two enterprises clearing tracks (SENA and
BUMA). As we described before, market liberalization will require a more
exible scheme to assign value activities to di erent enterprises, e.g. the
activities \Collect Fees" and \Repartition Fees" can be performed by di erent actors
rather than one actor. In order to address this problem we have generated and
analyzed variations in which several enterprises can cover di erent value
activities. We have used these variations to build a few e3value skeletons, however
because of space restrictions just one of these skeletons is described in the next
section.
4
4.1</p>
      <sec id="sec-3-1">
        <title>Consumer needs</title>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>Input elements for the con guration process</title>
      <p>For the con guration process, we assume that our consumer need is playing
background music and that we can cover such a need by providing a stream. In
addition, since the pay-per-play scenario must be analyzed, we also assume that
our stream contains only one music track. So, the need boils down to a streamed
track.
4.2</p>
      <sec id="sec-4-1">
        <title>Value skeletons</title>
        <p>The purpose of a skeleton is to abstract the set of relationships that are
involved in an e3value model. Later on, the instances of a skeleton will re ect a
speci c business case. In our approach, an e3value skeleton implies three
important features, which are described and explained by presenting our e3value
skeleton(Fig. 5).</p>
        <sec id="sec-4-1-1">
          <title>No actors, No market segments e3value skeletons focus on the de nition</title>
          <p>of value activities and not on actors or market segments. In fact, assigning
performing actors to value activities is an important part of con guring an e3value
instance model (see Sect. 5.4).</p>
          <p>No Selection The main idea behind skeletons is that there should be an
automatic process to instantiate speci c business models by lling the elements in
such skeleton. Therefore, this process must skip selection procedures like
choosing among di erent dependency paths or di erent actors, as is normally the case
in e3value models. In e3value words it means that we do not use OR-forks in
dependency paths nor market segments.</p>
          <p>On the use of Explosion Elements Consider the value transfers F-J in Fig. 3,
these value transfers involve the repartition of fees among right owners and look
very similar. By using explosion elements, we can abstract these transfers as
shown in Fig. 4.a. While generating an instance model, this abstraction can
be expanded to cover as many value activities as needed. In this example, we
assume that fees must be repartitioned among three right owners, hence three</p>
          <p>AND-extension ports are needed, which later allow connection with three other
value activities (Fig. 4.b).</p>
          <p>In the same way, our e3value skeleton (Fig. 5) depicts abstracted versions
of the value transfers B-E, K and L (Fig. 3), which are later instantiated into
new transfers. How the instantiation process of the skeleton works is explained
in Sect. 5.2. Finally, to facilitate reading, our skeleton also depicts short names
for some value objects. In this way, RIGHT MP refer to the Right for Making
Public a track, RIGHT CL is the Right to CoLlect fees, and RIGHT CT is the
Right to Clear a Track. The same holds for MONEY MP, MONEY CL and
MONEY CL.
4.3</p>
        </sec>
      </sec>
      <sec id="sec-4-2">
        <title>Con guration data</title>
        <p>The information about the environment in which the con guration process takes
place is the last element to be speci ed before starting the con guration process.
This environment, called con guration data, is composed of eight elements. The
main relationships among these elements are depicted in Fig. 6.</p>
        <p>Supply Chains The clearing process deals with ve types of suppliers:
artists, producers, composers, lyricists and publishers. Most of the time
suppliers bring about di erent dependency paths in which di erent value activities
and value objects are involved. We refer to these paths as supply chains. As can
be observed in Fig. 6, a supply chain consists of several activities, e.g. in our
case study, activities like Streaming, Collecting Fees, Repartitioning Fees and
Creating are needed to provide a track, i.e. supply a service. Actually, these are
the same activities that appear in the skeleton.</p>
        <p>Elementary Actors The elementary actors represent the set of service
providers willing to participate in a business case. In this sense, an elementary
actor has value interfaces to interact with other elementary actors.</p>
        <p>Value Activities In the same way, value activities represent the set of
activities that must be performed to cover a consumer need. Therefore value activities
has value interfaces for transfering value objects. As de ned in Fig. 6 a value
activity has a special relationship in which supply chains and elementary actors
are involved. In fact, this relationship yields an aggregation class, the same is
explained as follows.</p>
        <p>Performed-in By using this class we want to express that elementary
actors can only perform value activities related to speci c supply chains. As an
example, SENA only take care of activities like Collecting and Repartitioning
when they deal with artists and producers. BUMA does the same for the rest or
right owners.</p>
        <p>Value Interfaces A value interface is assigned-to either an elementary
actor or a value activity but not both at the same time, which is depicted by using
the XOR constraint. A value interface consists-of one or two value o erings,
what the actor wants and expects.</p>
        <p>Value O erings A value o ering represents what an actor o ers through
value interfaces. Therefore a value o ering is in a value interface and consists-of
values ports.</p>
        <p>Value Ports By using value ports an actor either o ers or requests value
objects. In addition a value port is only in one value o ering.</p>
        <p>Value Objects Value objects represent the services or products that actors
exchange to each other. For instance, according to our case study (Fig. 3), actors
exchange value objects like RIGHT MP, RIGHT CL and RIGHT CT.
5</p>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>Con guration process</title>
      <p>This process involves three phases. While the rst two phases are related to the
generation of a value activity network based on a given value skeleton, the third
phase matches the elements of the value network with a set of service providers.
5.1</p>
      <p>
        Selecting an e3value skeleton
The rst step to build an e3value instance model is related to selecting an e3value
skeleton from which the generation process can start. In this way, the e3value
skeletons must be chosen according to a consumer need, playing background
music (see Sect. 4.1). At this point we manually select an e3value skeleton. For
a guideline how to perform a semi-automatic process see [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ].
      </p>
      <sec id="sec-5-1">
        <title>Generating an e3value activity instance network</title>
        <p>Once a consumer need is de ned and an e3value skeleton is chosen (in this case
Fig. 5) , the generation process traverses this skeleton and produces an e3value
activity instance network. Algorithm 1 performs this process generating this
e3value activity instance network while traversing the skeleton based on a
depthrst traversal method, where the consumer need and the boundary element are
respectively the root and the leaf of the tree.</p>
        <p>Algorithm 1 considers each element in the skeleton. If the considered element
is not an explosion element, the element is simply copied into the value activity
instance network. If however the element is an explosion element, Algorithm 2
is executed, which evaluates the explosion elements and determines the number
of new AND-extension ports to be generated.
Algorithm 1 Generating an e3value activity instance network.
Explosion Parameters Each explosion element has a set of parameters. These
parameters are e3 explosion, ce related actor and ce refers to vo. How these
parameters work is explained in the Algorithm 2, and their e ect is illustrated in
Fig. 7.</p>
        <p>The parameter called e3 explosion controls whether the explosion element
will be evaluated. As can be observed in Fig. 7, there exist two ways to evaluate
the explosion element:
1. the explosion element will result in a number of parallel supply chains (See</p>
        <p>Fig. 7a/b, i.e. ce related actor == F ALSE),
2. the explosion element will result in a number of actors (Fig. 7c/d, i.e.</p>
        <p>ce related actor == T RU E).
5.3</p>
        <sec id="sec-5-1-1">
          <title>Running example</title>
          <p>We illustrate the case when a track, DE WAARHEID, is cleared on behalf of
three artists and two producers, i.e. two supply chains: one for artists and the
other one for producers. For readability we omit the composers, lyricists and
publishers. Therefore, Algorithm 1 travers the skeleton (Fig. 5). Once Algorithm 1
nds an explosion element, Algorithm 2 is applied to determine the number of
new AND-extension ports to be generated.</p>
          <p>For instance, assume that our algorithm walks down following the value
transfer related to STREAM/MONEY and nds the explosion element #2 (See
Algorithm 2 Determine the number of new AND-extension ports
if e3 explosion == T RU E then
if ce related actor == F ALSE then
value object = ce ref ers to vo
N ew AN D E ports = Number of supply chains in which value object is
involved
else
value object = current track
GET current supply chain
GET next value activity according to the skeleton
EA = set of actors performing next value activity in supply chain and o ering
value object</p>
          <p>N ew AN D E ports = Number of actors in EA.</p>
          <p>end if
else</p>
          <p>N ew AN D E ports = 1
end if
Fig. 5). The evaluation of this explosion element takes place i.e. Fig. 7 .a and 7.b.
This means that we have to count the number of supply chains, and we have
to generate the appropriate number of AND-extension ports for that. Since our
supply chains are artists and producers, and the RIGHT MP is involved in the
artists and producers supply chains, two new AND-extension ports must be
generated, as can be seen in Fig. 8, element #2.</p>
          <p>We continue to traverse the skeleton (for the artists supply chain) and nd
explosion element #3. This time, the evaluation is performed as in Fig. 7.c
and 7.d. The number of new AND-extension ports depends on the number of
elementary actors performing the Creating value activity in the artists supply
chain and for the speci c track, i.e. three artists. The process of copying elements
from the skeleton continues till reaching a boundary element. Fig. 8 depicts
the nal e3value activity network, the numbering indicates the order in which
element are instantiated.</p>
        </sec>
        <sec id="sec-5-1-2">
          <title>Assigning value activities to actors</title>
          <p>After generating the e3value activity network the next phase assigns activities to
service providers. In a naive-sequential way, Algorithm 3 describes this process.
Algorithm 3 Assign activities to actors</p>
          <p>As can be observed in Algorithm 3, there is a search to determine whether
an elementary actor can perform a value activity in a speci c supply chain (by
evaluating the performed-in association in Fig. 6). For instance, when assigning
the value activity Collecting Fees (Fig. 8, number 8), the algorithm will search
for an elementary actor that can perform this activity in the supply chain related
to producers. As we already know, SENA is able to perform such as activity in
that speci c supply chain, therefore the algorithm assigns this activity to SENA,
as shown in Fig. 9.
5.5</p>
        </sec>
        <sec id="sec-5-1-3">
          <title>Running example</title>
          <p>The model in Fig. 9 represents the way in which a set of enterprises work together
to cover a consumer need which is composed of two things: DE WAARHEID and
the needed rights to make this track public.</p>
          <p>As can be observed, the set of needed rights contains the rights from artists
and producers. Consequently, the consumer must contact to enterprise(s) taking
care of those rights, i.e. SENA. In the same way, since the stream provider is
making public DE WAARHEID, it also needs to get the same rights. In order
to get the rights from the set of right owners, SENA should also perform an
activity related to repartitioning fees.</p>
          <p>Furthermore, the activities related to repartitioning the fees contact the right
owners associated to DE WAARHEID. The supply chain related to artists ends
with three artists, whereas the supply chain of producers involves two right
owners.</p>
          <p>Finally, by applying the previous con guration approach, Sections 4 and 5,
we have generated di erent e3value instance models for other tracks. In this
way, we test that by just changing our con guration data i.e. actors, their value
objects and the activities they perform, we can generate instance models re-using
the same skeleton and applying our con guration process. Nevertheless, due to
lack of space these instance models are not presented 5.
6</p>
        </sec>
      </sec>
    </sec>
    <sec id="sec-6">
      <title>Conclusions and future work</title>
      <p>This paper has presented an approach to automatically generate e3value models,
based on skeletal design techniques. One of the objectives of our approach is to
re-use a set of value skeletons for covering an industry sector from which more
business cases may be generated. Consequently, in order to explain the intended
use of this approach we have also presented a case study.</p>
      <p>By following the idea of skeletal design we have exempli ed how re-use of
knowledge can help to solve the problem of massive service con guration. Our
e3value skeletons are useful to span (part of) an industry sector, helping to either
automate current tasks or forecast/explore new scenarios.</p>
      <sec id="sec-6-1">
        <title>Future work</title>
        <p>
          Our next steps will address the problems related to elicitation of consumer needs,
selection of skeletons and assignment of value activities to service providers, i.e.
to add more exibility to Algorithm 3. Consequently, while the work of Sybren
de Kinderen [
          <xref ref-type="bibr" rid="ref9">9</xref>
          ] represents a good base-line to deal with the rst issue, more
research must be done to evaluate whether hierarchical con guration or skeletal
planning could be implemented to cover our second issue.
        </p>
        <p>Finally, even though our approach solve our con guration problem, we are
aware of the limitations of this tool, mainly because some reasoning steps seems
to be case speci c. Therefore, more validation must be done and another case
study will be explored, related to the energy industry where more dynamic
behavior can be found.</p>
        <p>Acknowledgements. This paper has been partially funded by the
NWO/Jacquard project VALUE-IT no 630.001.205
5 The reader can consult some instances at: http://www.few.vu.nl/
izapata/GeneratingVM-SDT.php</p>
      </sec>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          1.
          <string-name>
            <given-names>J.</given-names>
            <surname>Gordijn</surname>
          </string-name>
          , S. de Kinderen,
          <string-name>
            <given-names>V.</given-names>
            <surname>Pijpers</surname>
          </string-name>
          , and
          <string-name>
            <given-names>H.</given-names>
            <surname>Akkermans</surname>
          </string-name>
          , \
          <article-title>e-services in a networked world: From semantics to pragmatics,"</article-title>
          <source>Lecture Notes in Computer Science</source>
          , vol.
          <volume>5468</volume>
          /
          <year>2009</year>
          , pp.
          <volume>44</volume>
          {
          <issue>57</issue>
          ,
          <year>2009</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          2.
          <string-name>
            <given-names>J.</given-names>
            <surname>Gordijn</surname>
          </string-name>
          ,
          <string-name>
            <given-names>E.</given-names>
            <surname>Yu</surname>
          </string-name>
          , and B. var der Raadt, \
          <article-title>e-service design using i * and e3value modeling,"</article-title>
          <source>IEEE Software</source>
          , vol.
          <volume>0740</volume>
          -
          <issue>7459</issue>
          /06, pp.
          <volume>26</volume>
          {
          <issue>33</issue>
          ,
          <year>2006</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          3.
          <string-name>
            <given-names>D.</given-names>
            <surname>Yang</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Dong</surname>
          </string-name>
          , and
          <string-name>
            <given-names>R.</given-names>
            <surname>Miao</surname>
          </string-name>
          , \
          <article-title>Development of a product con guration system with an ontology-based approach," Computer-Aided Design</article-title>
          , vol.
          <volume>40</volume>
          , pp.
          <volume>863</volume>
          {
          <issue>878</issue>
          ,
          <year>2008</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          4.
          <string-name>
            <given-names>J.</given-names>
            <surname>Gordijn</surname>
          </string-name>
          and
          <string-name>
            <given-names>J.</given-names>
            <surname>Akkermans</surname>
          </string-name>
          , \
          <article-title>e3-value: Design and evaluation of e-business models,"</article-title>
          <source>IEEE Intelligent Systems</source>
          , p.
          <fpage>1117</fpage>
          ,
          <year>2001</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          5.
          <string-name>
            <given-names>E.</given-names>
            <surname>Motta</surname>
          </string-name>
          ,
          <article-title>Reusable Components for Knowledge Modelling: Case Studies in Parametric Design Problem Solving</article-title>
          . IOS Press,
          <year>1999</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          6.
          <string-name>
            <given-names>B.</given-names>
            <surname>Wielinga</surname>
          </string-name>
          and G. Schreiber, \
          <article-title>Con guration design problem solving," IEEE Expert. Special issue on AI in Design</article-title>
          ., vol.
          <volume>12</volume>
          , pp.
          <volume>49</volume>
          {
          <issue>56</issue>
          ,
          <year>1997</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          7. G. Premkumar, \
          <article-title>Alternate distribution strategies for digital music,"</article-title>
          <source>Communications of the ACM</source>
          , vol.
          <volume>46</volume>
          , pp.
          <volume>89</volume>
          {
          <issue>95</issue>
          ,
          <year>2003</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          8.
          <string-name>
            <given-names>P.</given-names>
            <surname>Swatman</surname>
          </string-name>
          ,
          <string-name>
            <given-names>C.</given-names>
            <surname>Krueger</surname>
          </string-name>
          ,
          <article-title>and</article-title>
          K. van der Beek, \
          <article-title>The changing digital content landscape: An evaluation of e-business model development in european online news and music,"</article-title>
          <source>Internet Research</source>
          , vol.
          <volume>16</volume>
          , pp.
          <volume>53</volume>
          {
          <issue>80</issue>
          ,
          <year>2006</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          9. S. de Kinderen,
          <string-name>
            <given-names>J.</given-names>
            <surname>Gordijn</surname>
          </string-name>
          , and
          <string-name>
            <given-names>H.</given-names>
            <surname>Akkermans</surname>
          </string-name>
          , \
          <article-title>Eliciting multi-supplier customer needs-driven it-services bundles using compensatory and non-compensatory decision models,"</article-title>
          <source>1th International Conference on Enterprise Information Systems</source>
          , pp.
          <volume>131</volume>
          {
          <issue>136</issue>
          ,
          <year>2009</year>
          .
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>