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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>MPM4CPS: Multi-Paradigm Modelling for Cyber-Physical Systems</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Hans Vangheluwe</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Vasco Amaral</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Holger Giese</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Jan Broenink</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Bernhard Scha¨tz</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Alexander Norta</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Paulo Carreira</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Ivan Lukovic</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Tanja Mayerhofer</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Manuel Wimmer</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Antonio Vallecillo</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>University of Antwerp</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Belgium. (Hans.Vangheluwe@uantwerpen.be)</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>University of Potsdam</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Germany. (holger.giese@hpi.uni-potsdam.de)</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>University of Twente</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>The Netherlands. (j.f.broenink@utwente.nl)</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Fortiss</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Germany. (schaetz@fortiss.org)</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Tallin University of Technology</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Estonia. (alexander.norta@ttu.ee)</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Universidad de Lisboa</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Portugal. (paulo.carreira@ist.utl.pt)</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>University of Novi Sad</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Serbia. (ivan@uns.ac.rs)</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>TU Wien</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Austria. (</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>mayerhofer</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>wimmerg@big.tuwien.ac.at)</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Universidad de Ma´laga</string-name>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Spain. (av@lcc.uma.es)</string-name>
        </contrib>
      </contrib-group>
      <abstract>
        <p>The last decades have seen the emergence of truly complex, designed systems, known as Cyber-Physical Systems (CPS). Engineering such systems requires integrating physical, software, and network aspects. To date, neither a unifying theory nor systematic design methods, techniques and tools exist to meet this challenge. Individual engineering disciplines, such as mechanical, electrical, network and software engineering offer only partial solutions. Multi-Paradigm Modelling (MPM) proposes to model every part and aspect of a system, including development processes, explicitly, at the most appropriate level(s) of abstraction, using the most appropriate modelling formalism(s). Modelling language engineering, including model transformation, and the study of their semantics, are used to realize MPM. MPM is seen as an effective answer to the challenges of designing Cyber-Physical Systems. Research on modelling CPS is typically based on national activities with loose international interaction. To establish an interdisciplinary and inter-institutional platform for scientific information exchange, consensus building, and collaboration, the COST Action MPM4CPS, funded by the EU Framework Programme for Research and Innovation, has been initiated. MPM4CPS aims to develop and share foundations, techniques, and tools related to Multi-Paradigm Modelling for Cyber-Physical Systems (MPM4CPS) and to provide educational resources. In this paper we describe the overall MPM4CPS approach and its current status.</p>
      </abstract>
      <kwd-group>
        <kwd>Cyber-Physical Systems (CPS)</kwd>
        <kwd>Multi-paradigm Modelling (MPM)</kwd>
        <kwd>Model-Based Systems Engineering (MBSE)</kwd>
        <kwd>Multi-formalism</kwd>
        <kwd>Multi-abstraction</kwd>
        <kwd>(Co-)Simulation</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>Basic Project Information</p>
    </sec>
    <sec id="sec-2">
      <title>Background</title>
      <p>
        In virtually any area of human activity, truly complex, designed systems, known as
Cyber-Physical Systems (CPS) [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ], are emerging. These multi-disciplinary systems
deeply integrate collaborating physical, software, and network parts.
      </p>
      <p>
        The foundational infrastructure that is able to unify in a consistent way the plethora
of CPS facets is Multi-Paradigm Modelling (MPM) [
        <xref ref-type="bibr" rid="ref1 ref2 ref4">1, 2, 4</xref>
        ]. MPM is a research field
focused on breaking the inherent complexity of large-scale and complex systems into
different levels of abstraction and views (i.e., rigorous models of some physical or
logical reality), each expressed in an appropriate modelling formalism. By appropriate, not
only cognitive aspects (which impact learnability and usability of the formalism) are
meant, but also technical ones, such as tractability for debugging and analysis.
      </p>
      <p>Modelling language engineering (using model transformations), and the study of
their formal semantics, is used to realize MPM, by combining multiple models of
computation such as continuous-time, discrete-event, and synchronous data flow. MPM,
viewed as the logical continuation of Model-Based Systems Engineering (MBSE), is
becoming a successful approach by providing processes as well as software tools that
are able to combine, couple, and integrate each of the views that compose a system.
The main goals are to analyse (for safety and reliability), to simulate (for optimization
purposes) and, where appropriate, synthesize these systems.</p>
      <p>Research activities focusing on modelling CPS are typically based on national
activities and generally lack a concerted approach at European level. A dedicated
interdisciplinary and inter-institutional platform for scientific information exchange, consensus
building, and model improvement is thus required. COST provides the best available
mechanism for broad European networking and capability-building. A COST Action is
the most appropriate framework since only in a non-competitive, interdisciplinary
environment it will be possible to identify and verbalize the weaknesses and uncertainties
related to CPS modelling approaches, to develop common strategies for improving the
effectiveness of such methods, techniques and tools and to develop and broaden the
available research expertise.</p>
      <p>The COST Action MPM4CPS aims to involve, support and harmonize the various
existing national activities around CPS modelling. One innovative aspect of MPM4CPS
is the effort of bringing together scientists and experts in Mechatronics, Smart-Cities,
CPS, Software Modelling and Engineering, and Multi-Paradigm Modelling, in order
to push the development and implementation of state-of-the-art scientifically justified
methodologies of CPS modelling in several application domains, such as automotive
and avionics. In order to ensure a direct impact of the scientific output, MPM4CPS is
characterized by a high level of specialization and is aiming at a well defined target.
3</p>
    </sec>
    <sec id="sec-3">
      <title>Project Objectives</title>
      <p>The main aim of the MPM4CPS Action is to enhance the quality, visibility and impact
of European research and industrial adoption in the trans-disciplinary area of CPS. This
goal is pursued by building a network of researchers, educators, industrial practitioners
and policy makers in order to establish the foundations and methods of CPS
engineering enabled by MPM. This allows coordinating and shaping the efforts on research,
education and application in this emerging research field.</p>
      <p>The objectives of MPM4CPS are the following:
– Develop research-based guidelines for evaluating and characterizing CPS.
– Evaluate current software engineers’ practice and system engineers’ methods to
identify best practices as well as gaps and opportunities for unification.
– Develop hypotheses based on results of national research and development.
– Develop benchmark experiments in representative application domains of MPM4CPS.
– Develop and apply the MPM approach for combinations of different models,
modelling languages, simulation and verification tools and assert their applicability in
industry.
– Evaluate the interdisciplinary know-how required from a software/system’s
engineer in order to develop and maintain such kind of systems at the European scale,
and if necessary develop new course materials in order to cope with such needs.
– Disseminate information and results within several areas.
4</p>
    </sec>
    <sec id="sec-4">
      <title>Project Organization</title>
      <p>The MPM4CPS Action is planned to last four years and is operated with a
organizational structure in full accordance with COST guidelines.</p>
      <p>The activities within the Action are coordinated by the Management Committee
(MC) and organized around five Working Groups (see Section 4.1). Each participating
country has up to two representatives on the MC. MC members are nominated by the
COST National Coordinators (CNCs) of the countries they represent. The MC decides
on all budget-related questions, devises the general Action strategy and manages the
organisation of the Action’s scientific and technological activities. Balance of gender and
geographical representation is aimed for in the MC and in all WGs. Participation by
Early Stage Researchers (ESR – less than 8 years after PhD) is particularly stimulated.</p>
      <p>The Core Group (CG) consists of the chair and the vice-chair of the MC and the
leaders of each WG. The CG and ultimately the chair have responsibility for ensuring
that the MPM4CPS Action is on schedule and that specified objectives are met.</p>
      <p>High priority is given to Short Term Scientific Missions (STSM) to foster personal
contacts between researchers, where possible from diverse communities
(academiaindustry, inter-discipline). Regular calls for STSM proposals are planned. An STSM
Evaluation Committee assesses the impact of the scientific visits and their output, and
the CG decides on budget allocation.</p>
      <p>Training Schools are also key to the Action. In such Training Schools, the
challenges, concepts, methods, techniques and tools of MPM4CPS are taught. The intended
audience is PhD students and ESRs, including attendees from industry.
4.1</p>
      <sec id="sec-4-1">
        <title>Working Groups</title>
        <p>Four main Working Groups (WG1–WG4) make up the MPM4CPS Action and are in
charge of carrying out all activities. Participants are encouraged to be aware of and
participate in the activities of all WGs, intentionally avoiding a separation and
clustering of participants in mutually exclusive groups. In fact, a dedicated Working Group
(WG0) bundles cross-WG activities to ensure their cohesion and boost interdisciplinary
collaboration.</p>
        <p>WG0: Cross-WG Activities, Showcases. WG0 plays a special role within MPM4CPS
by bundling cross-WG activities in order to ensure their cohesion, boost
interdisciplinary collaborations, while avoiding the natural clustering (e.g., the creation of
microcommunities per working group) and minimizing fragmentation and duplication of
research and efforts within the large network formed by MPM4CPS. Exchanges between
the WGs is promoted, also by financially supporting inter-WG visits.</p>
        <p>Furthermore, WG0 oversees tasks related to dissemination towards end users,
including the design and development of showcases.</p>
        <p>WG1: Foundations - Intra- and Inter-Disciplinary Interaction. The objectives
of WG1 are to apply and mostly combine existing modelling techniques (e.g., MPM
techniques, Control Engineering techniques, Hybrid Systems) while dealing with the
heterogeneity of CPS, and identifying common formalisms and ontologies used in CPS
development. WG1 is in charge of characterizing/categorizing existing modelling
languages of the different disciplines using typical industrial CPS scenarios, and to
compile, evaluate, possibly complete and document existing modelling tools for CPS
modelling. Specific tasks of WG1 include:
– Identify existing CPS methodologies and state-of-the-art in CPS modelling and
development.
– Identify CPS tools and formalisms/disciplines that are currently under development
and favoured for future application.
– Identify the current generic modus-operandi of a typical industrial CPS developer.
– Define a standard terminology (i.e., domain ontology) for CPS.</p>
        <p>The deliverables of WG1 are based on previous and ongoing research work, and include
a state-of-the-art report on current formalisms used in CPS development, containing:
1) a structured catalogue of modelling languages and tools; and 2) a glossary of terms to
be used throughout CPS modelling language evaluation, development, and application.</p>
        <p>WG2: Techniques. The objective of WG2 is to conceptualize usable and efficient
MPM integrated environments for CPS development, while increasing CPS
development productivity (e.g., by means of increased interoperability, and use of visual
modelling languages) and reducing the complexity of CPS testing, simulation and
certification procedures. A secondary objective of WG2 is to investigate CPS standards that can
be used by Europeans regulators in order to increase performance, security and safety
of industrial CPS in Europe, and worldwide. Specific goals of WG2 are:
– Investigate which kind of MPM methods and tools are currently under development
(e.g., in the domains of software engineering, embedded systems, complex control
systems) and favoured for future application/integration in CPS.
– Help develop tools, standards and best practices that can be virtually integrated in
a conceptual MPM environment.
– Demonstrate and evaluate the increase of efficiency of such modelling
environments on CPS (i.e., not only in what matters to development speed, but also on
certification speed).</p>
        <p>As a consequence, the deliverables of WG2 include: 1) a report of standards and best
practices in MPM modelling of CPS; 2) a report on state-of-the-art in MPM modelling
tools used in different disciplines; 3) a report containing considerations for future MPM
modelling tools; and 4) an efficiency evaluation of MPM modelling tools on CPS (e.g.,
versus non-modelling approaches of CPS development and certification, etc.).</p>
        <p>WG3: Application Domains. WG3 focuses on the practical constraints in the use of
MPM modelling in two representative and distinct CPS application domains: 1)
embedded systems, control systems where CPS has emerged from (e.g., automotive,
aerospatial); and 2) more networked, unanticipated changes (both structure and behaviour) and
less of the traditional plant/controller architecture, which may have emergent behaviour
(e.g., smart-cities, complex traffic management). The specific needs of the industry in
these domains have to be taken into account in order to successfully implement the
scientific improvements gained by the MPM4CPS Action. WG3 works together with
industrial partners to ensure a bilateral feedback between the scientific and industrial
CPS communities. The main tasks covered in WG3 are the following:
– Define benchmark case studies.
– Assess the current industrial state of CPS and CPS modelling at a national level.
– Collect the requests and requirements of each application domain, and rewrite them
from a CPS perspective.
– Assess the suitability of the different application domain models.
– Compile recommendations on the proper use of different models, formalisms and
methodologies and the reliable assimilation of current application domain models
in the perspective of CPS modelling.</p>
        <p>The deliverables of WG3 are: 1) a documentation of recommended procedures for the
use of CPS models in the context of several application domains; 2) information on
which type of model(s) or approach(es) is/are to be used for which type of scenario;
3) practical guidelines for the optimal use of CPS models or MPM modelling
approaches;4) a report on the current state of the art of CPS and CPS modelling at a
national level.</p>
        <p>WG4: CPS Education and Dissemination. WG4 focuses on the crystallization of
MPM4CPS contents into a suitable format for dissemination and educational purposes.
The specific tasks covered in WG4 are:
– Identify the adequate profile(s) of CPS experts, i.e., minimum required knowledge
such as formalisms and modelling techniques.
– Identify existing courses in the realm of CPS and MPM4CPS in Europe, and the
need for new courses on topics relevant to CPS not yet covered by universities.
– Lay the foundations for a European Master/PhD program in MPM4CPS involving
several European leading universities and set up the respective discipline roadmap.
– Promote literature on the topic, and define course materials.
– Promote thematic Summer Schools on MPM4CPS for researchers.
– Make young students (future researchers and practitioners) aware of and
enthusiastic about the topic of CPS in events such as a “CPS Hacker School”.
4.2</p>
      </sec>
      <sec id="sec-4-2">
        <title>Networking Within MPM4CPS</title>
        <p>The following instruments are employed by MPM4CPS to pursue its objectives:
– Regular coordination meetings (at least two per year) putting particular emphasis
on technical discussions and presentations, and inviting representatives from EU
projects and external experts to participate in the technical discussions.
– A series of yearly workshops and symposia, inviting keynote speakers, lecturers
on software modelling and MPM, as well as CPS experts from both academia and
industry. These events will widen the information input and foster the immediate
dissemination of results produced by MPM4CPS.
– A series of annual reports surveying the state-of-the-art on MPM for CPS and
reporting case studies on the adoption of CPS technology in real-world applications.
– Yearly training school(s) for young researchers.
– Short Term Scientific Missions (STSM) for junior and senior participants.
– A website (http://www.mpm4cps.eu) for information exchange between the
members of the Action and to disseminate results.
– Internally, a project management portal with a set of thematic discussion forums
and mailing lists to foster collaboration between members.
4.3</p>
      </sec>
      <sec id="sec-4-3">
        <title>Participation</title>
        <p>COST Actions are by nature inclusive and actively encourage open participation. We
welcome new collaborators wishing to participate in the project and contribute to our
goals. If you want to get involved in the project or to be informed about future events
and new deliverables, please visit http://mpm4cps.eu/about/take_action.
5</p>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>Project Outcomes</title>
      <p>During the first year and a half most efforts have been focused on the exchange of
information among members, the identification of the main challenges, and the start of some
initial tasks in every working group. The basic management and project infrastructure
are already in place (WG0). WG1 is actively working on a common ontology for CPS.
WG2 currently focuses on tools and processes for co-simulation. WG3 collects a set
of standard practices in industry and defines target application domains. Finally, WG4
has set up the web portal and is preparing course material on MPM and CPS. Concrete
deliverables for all these activities are planned by October 2016.</p>
      <p>WG and MC Meetings are being held as planned, trying to collocate either with
modeling or with CPS events (such as the CPSweek, for instance). A Young Researcher
Workshop (in Twente, The Netherlands) and Training School (in Tallinn, Estonia) have
taken place, and new ones are expected soon, together with new calls for STSM.
Register at http://mpm4cps.eu/about/take_action to receive information about
forthcoming events and calls.</p>
      <p>Apart from the outcomes of the individual WGs discussed above, in the last year of
the action a summarizing report will be finalized, peer-reviewed and published.
6</p>
    </sec>
    <sec id="sec-6">
      <title>Exploitation Approach and Expected Impact</title>
      <p>The potential impact of MPM4CPS can be characterized as follows:
– Formation of a dedicated trans-disciplinary, cross-national pool for information
exchange intended to last far beyond the lifetime of the MPM4CPS Action.
– Increased quality and level of inter-disciplinarity of MPM for CPS research.
– Reducing fragmentation of research through the definition of a common research
agenda on MPM for CPS, and by bringing together experts from both research and
industry (MPM4CPS community building).
– Promoting MPM and CPS education by defining the MPM4CPS discipline, while
identifying the required profile for CPS expertise, and the core of topics,
competencies and specialities in MPM4CPS education.
– Synergy between industrial partners from different application domains around
CPS (expected economical benefits for the European region and leadership
establishment of the European institutions in the MPM4CPS area).
– Enhanced competitiveness of European ICT industry by: 1) fostering the adoption
of the MPM4CPS practices and methodologies, capable of boosting the
productivity of the development process of existing and new complex application domains,
and 2) creating new markets for CPS tooling.
7</p>
    </sec>
    <sec id="sec-7">
      <title>Barriers and Obstacles, and Expected Marketing Value</title>
      <p>The number, heterogeneity and different backgrounds of the participants can be
considered as strong points, but also introduces significant challenges. Coordination and
synchronization of efforts and resources are critical tasks for this Action.</p>
      <p>The lack of maturity of some of the methods and tools currently used in some of the
disciplines covered by the Action may represent a real impediment for the industrial
adoption of the MPM4CPS approach. Being an COST Action we can identify what is
missing or immature. We expect (EU) projects spinning off from this Action to address
the limitations and issues encountered, in order to facilitate the full industrial adoption
of MPM4CPS practices and tools. Moreover, information about state-of-the-art
embedded systems, mechatronics for avionics, mechatronics for automotive, etc., are already
exchanged among European countries, but mostly via independent application-specific
industrial standards. There is a clear need to bring different solutions from different
technology and application domains together around CPS.</p>
      <p>This action aims at creating the conditions necessary for promoting the sharing of
resources, by integrating, under a common umbrella (i.e., in a consistent and
systematic way with a common terminology), the knowledge and experiments across several
research projects around Europe (and beyond). In addition, it provides a unique
opportunity to establish international cooperation, and to exchange materials (data, models,
insights) and compare results. Finally, this Action is expected to provide input to
European policy with respect to regulations of the methodologies and procedures to develop
and certify this kind of systems, combining national and international legislation. Here
is a unique opportunity to determine appropriate ways of dealing with CPS in different
industrial environments.
8</p>
    </sec>
    <sec id="sec-8">
      <title>References to Related Work and Related Projects</title>
      <p>The MPM4CPS Action focuses on MPM for CPS, and these aspects combined are
not covered by other COST Actions or EU-projects. As the Action necessarily has to
include many aspects of CPS (e.g., mechatronics in several application domains), there
are links with other research programmes as indicated in the following:
a) Links and complementarity with other COST Actions
– IC0901 - Rich-Model Toolkit - An Infrastructure for Reliable Computer
– IC285 - Modelling and Simulation Tools for Research in Emerging
Multiservice Telecommunications
b) Links with other EU research programmes
– Cyber-Physical Systems European Roadmap and Strategy (CyPhERS).
– CPS Action Line “Cyber Physical Systems” of the EIT ICT KIC.
– Industrial Framework for Embedded Systems Tools (iFEST).
– Combined Model-based Analysis and Testing of Embedded Systems (MBAT).
– Integrated Tool Chain for Model-based Design of CPS (INTO-CPS).
– Trans-Atlantic Modelling and Simulation for Cyber-Physical Systems (TAMS4CPS).
Acknowledgements. COST IC 1404 MPM4CPS is supported by the EU Framework
Programme Horizon 2020.</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          1.
          <string-name>
            <surname>Amaral</surname>
            ,
            <given-names>V.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Hardebolle</surname>
            ,
            <given-names>C.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Vangheluwe</surname>
            ,
            <given-names>H.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Lengyel</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Bunus</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          :
          <article-title>Recent advances in multiparadigm modeling</article-title>
          .
          <source>ECEASST</source>
          <volume>50</volume>
          (
          <year>2011</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          2.
          <string-name>
            <surname>Mosterman</surname>
            ,
            <given-names>P.J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Vangheluwe</surname>
          </string-name>
          , H.:
          <article-title>Guest editorial: Special issue on computer automated multiparadigm modeling</article-title>
          .
          <source>ACM Trans. Model. Comput. Simul</source>
          .
          <volume>12</volume>
          (
          <issue>4</issue>
          ),
          <fpage>249</fpage>
          -
          <lpage>255</lpage>
          (
          <year>Oct 2002</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          3.
          <string-name>
            <surname>Rajkumar</surname>
            ,
            <given-names>R.R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Lee</surname>
            ,
            <given-names>I.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sha</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Stankovic</surname>
          </string-name>
          , J.:
          <string-name>
            <surname>Cyber-Physical</surname>
            <given-names>Systems</given-names>
          </string-name>
          :
          <article-title>The Next Computing Revolution</article-title>
          .
          <source>In: Proc. of DAC'10</source>
          . pp.
          <fpage>731</fpage>
          -
          <lpage>736</lpage>
          . ACM (
          <year>2010</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          4.
          <string-name>
            <surname>Vangheluwe</surname>
          </string-name>
          , H., de Lara, J.,
          <string-name>
            <surname>Mosterman</surname>
            ,
            <given-names>P.J.:</given-names>
          </string-name>
          <article-title>An introduction to multi-paradigm modelling and simulation</article-title>
          .
          <source>In: Proceedings of the AIS'2002 Conference (AI, Simulation and Planning in High Autonomy Systems)</source>
          . pp.
          <fpage>9</fpage>
          -
          <lpage>20</lpage>
          (
          <year>April 2002</year>
          ), Lisboa, Portugal.
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>