Veröffentlichungen

2018

  • [DOI] T. Mersch, “Regelbasierte Modelltransformation in prozessleittechnischen Laufzeitumgebungen,” Dissertation PhD Thesis, Düsseldorf, 2018.
    [Bibtex]
    @PHDTHESIS{Mersch:748566,
          author       = {Mersch, Tina},
          othercontributors = {Epple, Ulrich and Schürr, Andy},
          title        = {{R}egelbasierte {M}odelltransformation in
                          prozessleittechnischen {L}aufzeitumgebungen},
          volume       = {1261},
          school       = {RWTH Aachen University},
          type         = {Dissertation},
          address      = {Düsseldorf},
          publisher    = {VDI Verlag GmbH},
          reportid     = {RWTH-2018-229492, Reihe 8 . Nr. 1261},
          series       = {Fortschritt-Berichte VDI : Reihe 8, Mess-, Steuerungs- und
                          Regelungstechnik},
          pages        = {1 Online-Ressource (VIII, 152 Seiten) : Illustrationen},
          year         = {2018},
          note         = {Auch veröffentlicht auf dem Publikationsserver der RWTH
                          Aachen University; Dissertation, RWTH Aachen University,
                          2017},
          abstract     = {A survey of 1800 members of the German engineering
                          association VDMA [Sch12] showed that $61\%$ of development
                          and design engineers surveyed don’t feel up to the
                          challenges in the development of new machines and equipment.
                          More than one half of the respondents expect that the
                          development of efficient, powerful and flexible machines
                          will become even more complex in future. In addition, they
                          predict that users and operators will become less qualified.
                          This concurrence of increasing complexity and decreasing
                          knowledge demands new methods in the engineering of plants.
                          Anne Schneller, author of the VDI article about the survey,
                          suggests that automation technology has to progress toward
                          "parameterization instead implementation" to cope with these
                          challenges. The work at hand aims to contribute to make this
                          paradigma applicable for complex automation functions. The
                          approach presented in this work takes advantage of the
                          strong correlation between different models of plants. It
                          uses model transformation as the basis of a system-neutral
                          development of automation functions. Those automation
                          functions can be parametrized with the plant specific
                          planning data without further coding costs. The knowledge
                          about the model correlations is stored once as rules,
                          available for a large set of plants. The method of
                          rule-based model transformation has its roots in computer
                          science, where the approaches already developed achieved
                          significant results in the model worlds created for them.
                          Despite of many years of progress in the field of model
                          transformation, automation technology presents special
                          challenges for adoption. In particular, semiformal model
                          descriptions and the variances in modelling as well as
                          multiple source models make the use of standard methods
                          impossible. Not only are the high demands of computer
                          science on formalization and the fit of the participating
                          models a hurdle in merging the two disciplines but the
                          conservative attitude of automation technology brings
                          particular challenges with it as well. One requirement for
                          the acceptance of these approaches in automation technology
                          is the smooth integration of the concepts in the application
                          domain without ignoring the domain experts. The concept
                          presented realizes one of the most promising approaches from
                          computer science and integrates it seamlessly into
                          automation programming. With this approach the installation
                          technician can combine model transformation and standard
                          programming in accordance with his purposes.},
          cin          = {526610 / 520000},
          ddc          = {620},
          cid          = {$I:(DE-82)526610_20140620$ / $I:(DE-82)520000_20140620$},
          typ          = {PUB:(DE-HGF)11 / PUB:(DE-HGF)29 / PUB:(DE-HGF)3},
          doi          = {10.18154/RWTH-2018-229492},
          url          = {https://publications.rwth-aachen.de/record/748566},
    }

2012

  • L. Yu, G. Quirós, T. Krausser, and U. Epple, ACPLT + IEC 61131-3: A Dynamically Reconfigurable Automation PlatformGI – Gesellschaft für Informatik, 2012.
    [Bibtex]
    @proceedings{YuQuKr12,
      abstract = {Programming environments applying the IEC 61131 standard follow the "traditional" development cycle: edit/compile/load/execute. In case execution code needs to be modified, interruption of the execution is necessary. In this paper, we present an approach that combines object oriented technologies of the ACPLT framework with the standard IEC 61131-3 languages Function Block Diagram (FBD) and Sequential Function Chart (SFC). In contrast to traditional systems, the entire object-oriented meta-model of FBDs and SFCs is available on the runtime system. A great advantage of this design is the possibility of online exploration of meta-information and dynamic reconfiguration of the system without interruption. This is especially useful for maintenance and re-engineering tasks for chemical and metallurgical plants, where interruption is often associated with high economic lost.},
      author = "Yu, Liyong and Quir{\'o}s, Gustavo and Krausser, Tina and Epple, Ulrich",
      booktitle = "{Proceedings of MOD 2012}",
      conference = "MAT 2012 held in conjunction with Modellierung 2012",
      detailurl = "mat-2012",
      language = "en",
      month = "mar",
      publisher = "GI - Gesellschaft f{\"u}r Informatik",
      title = "{ACPLT + IEC 61131-3: A Dynamically Reconfigurable Automation Platform}",
      year = "2012"
    }
  • M. Schlereth and T. Krausser, “Platform-Independent Specification of Model Transformations at Runtime Using Higher-Order Transformations,” in Proceeding MOD 2012, Bamberg, Germany, 2012.
    [Bibtex]
    @inproceedings{ScKr12,
      abstract = "Model transformation specifications are currently bound to a specific transformation execution engine, typically executed on desktop systems. This paper presents a novel approach to transform platform-independent model transformation specifications into platform-specific model transformation specifications, which can be executed for example by the runtime systems of process control systems employed in plant automation. For that purpose, the concept of higher-order transformations was adapted to the transformation between platform-independent and platform-specific models of model transformations.",
      address = "Bamberg, Germany",
      author = "Schlereth, Michael and Krausser, Tina",
      booktitle = "{Proceeding MOD 2012}",
      conference = "Modellierung 2012",
      detailurl = "mod-2012",
      language = "en",
      month = "mar",
      publisher = "GI - Gesellschaft f{\"u}r Informatik",
      title = "{Platform-Independent Specification of Model Transformations at Runtime Using Higher-Order Transformations}",
      year = "2012"
    }
  • T. Krausser, L. Evertz, and U. Epple, “A Hands-On Laboratory on Industrial Hardware, Process Control and Advanced Automation,” in Proceedings of ACE 2012, Nizhny Novgorod, Russia, 2012.
    [Bibtex]
    @inproceedings{KrEvEp12,
      abstract = "The field of process control comprises a wide set of functions along the life-cycle and through all levels of the automation system pyramid. To give students a glance of the complexity of process control it is important to provide them the possibility to try as many functionality as possible at own hand. That is why the practice on industrial relevant hard- and software should be an important part of control education. Beside theoretical basics given in lectures, study trips to industrial plants and deepening loop-control-laboratories a laboratory along the levels of the automation pyramid as well as along the life-cycle of a plant give the students the big picture of process automation. This paper presents the challenges, requirements and concepts for such a laboratory. The presentation of the resulting laboratory plant as well as a field report about five years ongoing labs finalize the paper.",
      address = "Nizhny Novgorod, Russia",
      author = "Krausser, Tina and Evertz, Lars and Epple, Ulrich",
      booktitle = "{ Proceedings of ACE 2012}",
      conference = "ACE 2012",
      detailurl = "ace-2012",
      language = "en",
      month = "jun",
      publisher = "IFAC",
      title = "{A Hands-On Laboratory on Industrial Hardware, Process Control and Advanced Automation}",
      year = "2012"
    }
  • T. Krausser, H. Mersch, and U. Epple, ” Rule-based Adaption of Distributed Automation Systems at Operation Time,” in Proceedings of INCOM 2012, Bucharest, Romania, 2012.
    [Bibtex]
    @inproceedings{KrMeEp12,
      abstract = "The distribution of automation system functionality to different components is a particular challenge for the modification of the whole system at operation time. The consistency throughout all components has to be guaranteed even if an adaption addresses the change of an element that has an effect on dependent elements anywhere in the system. A framework is presented for the automatic adaption of dependent elements according to the underlying dependency rules. Therefore, the conditions for an automatic adaption of a distributed automation system are illustrated and especially the challenges that come along with the adaption at operation time are elucidated. The paper proposes the embedment of the rule-based automation system engineering into a service-oriented architecture. The developed concept is evaluated with the help of a prototype implementation and with the application of the prototype to a demonstration pumping plant. Further investigations, especially in the domain of formal engineering guidelines, are elucidated.",
      address = "Bucharest, Romania",
      author = "Krausser, Tina and Mersch, Henning and Epple, Ulrich",
      booktitle = "{Proceedings of INCOM 2012}",
      conference = "INCOM 2012",
      detailurl = "incom-2012",
      language = "en",
      month = "may",
      publisher = "IFAC",
      title = "{ Rule-based Adaption of Distributed Automation Systems at Operation Time}",
      year = "2012"
    }
  • T. Krausser, M. Lauder, M. Schlereth, U. Epple, and Schürr, ” Integrated Graph Transformations in Automation Systems ,” in Proceedings of MATHMOD 2012 , Vienna, Austria, 2012.
    [Bibtex]
    @inproceedings{KrLaSc12,
      abstract = "A crucial part of the automation system engineering consists of the reconciliation of engineering models. Hence, information from a source model is used to generate instances of a target model. For example, for each element in the plant and instrumentation diagram (P\&ID) a corresponding representative is generated on the operator screen of the human machine interface (HMI). Most of those reconciliations follow simple rules. Nevertheless, due to the lack of tool support, most of this work is done manually. On the other hand, well studied transformation techniques exist, whichin the field of model driven development. The paper combines the concept of model transformation with the help of triple graph grammars (TGGs) and the approach of an integrated rule-based system to gain a formal background for the model transformation at runtime of an automation system. It will be emonstrated that TGGs are suitable to formulate the transformation rules in automation system engineering and that the rules can be generated by the system engineer without additional knowledge. Further, the paper proposes the adaption of the existing rule-based system ACPLT/RE to the concepts of bidirectional TGG rules to benefit from the possibilities of the TGG concept for model transformation at runtime. Finally the potential of model transformation at runtime with special focus on automation system engineering is demonstrated with the help of the flow analysis example.",
      address = "Vienna, Austria",
      author = "Krausser, Tina and Lauder, Marius and Schlereth, Michael and Epple, Ulrich and Sch{\"u}rr",
      booktitle = "{ Proceedings of MATHMOD 2012 }",
      conference = "MATHMOD 2012",
      detailurl = "mathmod-2012",
      editor = "Troch, Inge",
      language = "en",
      month = "feb",
      publisher = "IFAC",
      title = "{ Integrated Graph Transformations in Automation Systems }",
      year = "2012"
    }

2011

  • [PDF] T. Krausser and G. Quirós, ” An IEC-61131-based Rule System for Integrated Automation Engineering: Concept and Case Study ,” in Proceedings of INDIN 2011 , Caparica, Lisbon, Portugal, 2011.
    [Bibtex]
    @inproceedings{KrQu11,
      abstract = "In this paper we present a rule-based system that has its purpose in automation engineering and can be implemented in a common automation environment without additional software. Our rule-based system uses IEC 61131 program organization units to formulate the rules as blueprints of the intended network of function blocks, functions or programs. Hence, the engineer can develop in his preferred programming language, but instead of writing out the implementation of each instance in full, he develops a single blueprint representation of the intended context. The paper gives an overview of the implementation requirements for this approach and reviews the advantages and problems of an integrated rule-based system. Finally, we adapt this concept to implement a rule-based version of flow path analysis in an piping system. On the base of the implemented example, we demonstrate the feasibility of the presented concept. A forecast on future fields of application finalizes the paper.",
      address = "Caparica, Lisbon, Portugal",
      author = "Krausser, Tina and Quir{\'o}s, Gustavo",
      booktitle = "{ Proceedings of INDIN 2011 }",
      conference = "INDIN 2011",
      isbn = "978-1-4577-0433-8",
      language = "en",
      title = "{ An IEC-61131-based Rule System for Integrated Automation Engineering: Concept and Case Study }",
      year = "2011"
    }
  • L. Yu, T. Krausser, and G. Quirós, ” SFC und Ein durchgängiges Beschreibungsmittel über die Grenzen der Basisautomatisierung hinaus? ,” in Automation 2011 : der 12. Branchentreff der Mess- und Automatisierungstechnik , P. Adolphs, Ed., Düsseldorf, Germany: VDI Wissensforum GmbH, 2011, vol. VDI-Berichte 2143, pp. 347-350.
    [Bibtex]
    @incollection{YuKrQu11,
      abstract = "Die Sprachen SFC und FBD der IEC 61131-3 [1] sind ein etabliertes Mittel zur Beschreibung von automatisierten Abl{\"a}ufen und Implementierungen. Neben dem herk{\"o}mmlichen Einsatz in der Prozessleitebene bieten sich diese Sprachen jedoch auch zur nativen Funktionsbeschreibung in weiteren Anwendungsdom{\"a}nen der Automatisierungstechnik an. Dieser Beitrag beleuchtet die M{\"o}glichkeiten, die ein durchg{\"a}ngiges Beschreibungsmittel {\"u}ber alle Dom{\"a}nen und Lebenszyklusphasen hinweg mit sich bring und zeigt das Potenzial, dass der Einsatz der grafischen IEC 61131-3 Sprachmittel als ein solches durchg{\"a}ngiges und universales Beschreibungsmittel bietet.",
      address = "D{\"u}sseldorf, Germany",
      author = "Yu, Liyong and Krausser, Tina and Quir{\'o}s, Gustavo",
      booktitle = "{ Automation 2011 : der 12. Branchentreff der Mess- und Automatisierungstechnik }",
      conference = "AUTOMATION 2011",
      editor = "Adolphs, Peter",
      isbn = "978-3-18-092143-3",
      issn = "0083-5560",
      language = "de",
      organization = "VDI/VDE-Gesellschaft f{\"u}r Mess- und Automatisierungstechnik",
      pages = "347--350",
      publisher = "VDI Wissensforum GmbH",
      title = "{ SFC und Ein durchg{\"a}ngiges Beschreibungsmittel {\"u}ber die Grenzen der Basisautomatisierung hinaus? }",
      volume = "VDI-Berichte 2143",
      year = "2011"
    }

2010

  • [PDF] T. Krausser, S. Schmitz, and L. Yu, ” Regelbasierte Vollständigkeitsüberprüfung von Automatisierungslösungen ,” in Automation 2010 : der 11. Branchentreff der Mess- und Automatisierungstechnik ; Kongress Baden-Baden, 15. und 16. Juni 2010 , K. D. Bettenhausen, Ed., Düsseldorf, Germany: VDI Wissensforum GmbH, 2010, vol. VDI-Berichte 2092, pp. 55-58.
    [Bibtex]
    @incollection{KrScYu10,
      abstract = "Mit der Nutzung von Computern f{\"u}r die Automatisierungstechnik wurden in den letzten Jahrzehnten eine ganze Reihe neuer Anwendungsgebiete f{\"u}r die Optimierung der Anlagen- und Prozessautomatisierung geschaffen. Bis zur Inbetriebnahme einer Anlage m{\"u}ssen daher heute eine Reihe einzelner Automatisierungskomponenten umgesetzt werden. Um die einzelnen Komponenten einer Automatisierungsl{\"o}sung ohne zeitliche Verluste verkn{\"u}pfen zu k{\"o}nnen, m{\"u}ssen sie jede f{\"u}r sich zuvor auf Vollst{\"a}ndigkeit und Korrektheit {\"u}berpr{\"u}ft werden. Der Einsatz von komponenten-{\"u}bergreifenden Regeln und einem darauf basierenden Regelbasierten System bietet eine elegante M{\"o}glichkeit, das Wissen zu sammeln, zu strukturieren und f{\"u}r die durchg{\"a}ngige berpr{\"u}fung der Vollst{\"a}ndigkeit der einzelnen Komponenten einer Automatisierungsl{\"o}sung zug{\"a}nglich zu machen. Wir beleuchten in diesem Beitrag zun{\"a}chst die Rahmenbedingungen, denen ein Regelbasiertes System im Umfeld der Automatisierungstechnik unterliegt. Ein Aspekt, dem dabei eine besondere Beachtung zukommt, ist die einfache Integrierbarkeit in vorhandene Leitsysteme und Automatisierungswerkzeuge. Das entwickelte Regelbasierte System wird anhand einer Referenzimplementierung f{\"u}r die berpr{\"u}fung der Vollst{\"a}ndigkeit von Automatisierungsl{\"o}sungen veranschaulicht. Diese Referenzimplementierung kam bereits bei verschiedenen Automatisierungsprojekten im metallverarbeitenden sowie chemischen-verfahrenstechnischen Umfeld zum Einsatz. Anwendungsbeispiele aus diesen Projekten wie die berpr{\"u}fung der Vollst{\"a}ndigkeit der implementierten Einzelsteuerungen auf Basis eines XML-basierten Anagenmodells erg{\"a}nzen den Beitrag.",
      address = "D{\"u}sseldorf, Germany",
      author = "Krausser, Tina and Schmitz, Stefan and Yu, Liyong",
      booktitle = "{ Automation 2010 : der 11. Branchentreff der Mess- und Automatisierungstechnik ; Kongress Baden-Baden, 15. und 16. Juni 2010 }",
      conference = "AUTOMATION 2010",
      editor = "Bettenhausen, Kurt D.",
      isbn = "978-3-18-092092-4",
      issn = "0083-5560",
      language = "de",
      organization = "VDI/VDE-Gesellschaft f{\"u}r Mess- und Automatisierungstechnik",
      pages = "55--58",
      publisher = "VDI Wissensforum GmbH",
      title = "{ Regelbasierte Vollst{\"a}ndigkeits{\"u}berpr{\"u}fung von Automatisierungsl{\"o}sungen }",
      volume = "VDI-Berichte 2092",
      year = "2010"
    }

2008

  • [PDF] T. Krausser, U. Epple, and C. Haus, ” UniFeBu – Ein Universeller Feldbuszugang ,” in Automation 2008 : Lösungen für die Zukunft ; Tagung Baden-Baden, 3. und 4. Juni 2008 ; [mit CD-ROM] / Der Automatisierungskongress in Deutschland. VDI/VDE-Gesellschaft Meß- und Automatisierungstechnik , K. D. Bettenhausen, Ed., Düsseldorf, Germany: VDI Wissensforum GmbH, 2008, vol. VDI-Berichte 2032, pp. 309-312.
    [Bibtex]
    @incollection{KrEpHa08,
      abstract = "Der in diesem Beitrag vorgestellte Universelle Feldbuszugang (UniFeBu) hat zum Ziel, Anwendungsentwicklern sowie Ger{\"a}teherstellern ein schlankes Rahmenwerk an die Hand zu geben, das einen einheitlichen Zugang zu den unterschiedlichen Feldbussystemen bietet, ohne die Funktionalit{\"a}t der einzelnen Systeme oder die verwendete Hardware einzuschr{\"a}nken. Ziel des UniFeBu ist, die zu Gunde liegenden Kommunikationsformen herauszuarbeiten, die bei allen Feldbussystemen gleich sind. Basierend auf den dabei gewonnenen Informationen wird ein durchg{\"a}ngiges Modell zur Verf{\"u}gung gestellt, das die Spezifika der Feldbus- und Zugangskarten auf diesen allgemeinen Kommunikationsformen abbildet.",
      address = "D{\"u}sseldorf, Germany",
      author = "Krausser, Tina and Epple, Ulrich and Haus, Christina",
      booktitle = "{ Automation 2008 : L{\"o}sungen f{\"u}r die Zukunft ; Tagung Baden-Baden, 3. und 4. Juni 2008 ; [mit CD-ROM] / Der Automatisierungskongress in Deutschland. VDI/VDE-Gesellschaft Me{\ss}- und Automatisierungstechnik }",
      conference = "AUTOMATION 2008",
      editor = "Bettenhausen, Kurt D.",
      isbn = "978-3-18-092032-0",
      issn = "978-3-18-092032-0",
      language = "de",
      organization = "VDI/VDE-Gesellschaft f{\"u}r Mess- und Automatisierungstechnik",
      pages = "309--312",
      publisher = "VDI Wissensforum GmbH",
      title = "{ UniFeBu - Ein Universeller Feldbuszugang }",
      volume = "VDI-Berichte 2032",
      year = "2008"
    }

2007

  • [PDF] T. Krausser, H. Mantel, and H. Sudbrock, ” A Probabilistic Justification of the Combining Calculus under the Uniform Scheduler Assumption ,” , AIB-2007-09, 2007.
    [Bibtex]
    @techreport{KrMaSu07,
      abstract = "The combining calculus provides a framework for analyzing the information flow of multi-threaded programs. The calculus incorporates so called plug-in rules for integrating several previously existing analysis techniques. By applying a plug-in rule to a subprogram, one decides to analyze this subprogram with the given analysis technique, and not with the rules of the combining calculus. The novelty of the combining calculus was that one can analyze the information flow security of a given program by using multiple analysis techniques in combination. It was demonstrated that this flexibility leads to a more precise analysis, allowing one to successfully verify the security of some programs that cannot be verified with any of the existing analysis techniques in isolation. In MSK07, the soundness of the combining calculus is proved for a possibilistic characterization of information flow security. This characterization assumes a purely nondeterministic scheduling of concurrent threads. In this report, we demonstrate that the combining calculus is also sound for a probabilistic characterization of security that assumes a uniform scheduler. This result further increases the confidence in the combining calculus as a reliable and flexible tool for formally analyzing the information flow security of multi-threaded programs.",
      author = "Krausser, Tina and Mantel, Heiko and Sudbrock, Henning",
      booktitle = "{ Technical Reports 2007 }",
      language = "en",
      month = "may",
      number = "AIB-2007-09",
      organization = "Department of Computer Science / RWTH Aachen",
      title = "{ A Probabilistic Justification of the Combining Calculus under the Uniform Scheduler Assumption }",
      url = "http://sunsite.informatik.rwth-aachen.de/Publications/AIB/2007/2007-09.pdf",
      year = "2007"
    }
  • H. Mantel, H. Sudbrock, and T. Krausser, ” Combining Different Proof Techniques for Verifying Information Flow Security ,” in Logic Based Program Synthesis and Transformation (LOPSTR’06) , A. M. King, Ed., Springer, 2007, vol. 4407.
    [Bibtex]
    @incollection{MaSuKr07,
      author = "Mantel, Heiko and Sudbrock, Henning and Krausser, Tina",
      booktitle = "{ Logic Based Program Synthesis and Transformation (LOPSTR'06) }",
      conference = "LNCS, 4407. Springer",
      editor = "King, Andrew Malcolm",
      isbn = "978-3-540-78768-6",
      journal = "LNCS",
      language = "en",
      publisher = "Springer",
      title = "{ Combining Different Proof Techniques for Verifying Information Flow Security }",
      volume = "4407",
      year = "2007"
    }

2006

  • [PDF] H. Mantel, H. Sudbrock, and T. Krausser, ” Combining Different Proof Techniques for Verifying Information Flow Security ,” in Pre-Proceedings of 16th International Symposium on Logic Based Program Synthesis and Transformation (LOPSTR 2006) , 2006, pp. 85-101.
    [Bibtex]
    @inproceedings{MaSuKr06,
      abstract = "When giving a program access to secret information, one must ensure that the program does not leak the secrets to untrusted sinks. For reducing the complexity of such an information flow analysis, one can employ compositional proof techniques. In this article, we present a new approach to analyzing information flow security in a compositional manner. Instead of committing to a proof technique at the beginning of a verification, this choice is made during verification with the option of flexibly migrating to another proof technique. Our approachalso increases the precision of compositional reasoning in comparison to the traditional approach. We illustrate the advantages in two exemplary security analyses, on the semantic level and on the syntactic level.",
      author = "Mantel, Heiko and Sudbrock, Henning and Krausser, Tina",
      booktitle = "{ Pre-Proceedings of 16th International Symposium on Logic Based Program Synthesis and Transformation (LOPSTR 2006) }",
      conference = "LOPSTR 2006",
      editor = "Puebla, Germ'an",
      language = "en",
      month = "July 12-14",
      pages = "85--101",
      publisher = "Raporta di Ricerca CS-2006-5, Universit{`a} Ca' Foscari Di Venezia",
      title = "{ Combining Different Proof Techniques for Verifying Information Flow Security }",
      url = "http://www.fmis.informatik.tu-darmstadt.de/WebBib/papers/2006/lopstr-2006-preproceedings.pdf",
      year = "2006"
    }

2005

  • [PDF] T. Krausser, Monadische Hoare-Logik in Isabelle , 2005.
    [Bibtex]
    @unpublished{Kr05,
      author = "Krausser, Tina",
      booktitle = "{ Diploma Thesis }",
      language = "de",
      school = "University of Bremen",
      title = "{ Monadische Hoare-Logik in Isabelle }",
      url = "http://tina.krausser.net/assets/documents; / Krausser_DiplomaThesis.pdf",
      year = "2005"
    }