Bio:

Project member: Language Engineering for Multilevel Modelling (LE4MM)

Curriculum Vitae:

• 2001-2009: Studies of Computer Science (Dipl. I + MSc) University of Kassel
• 2009-2015: Research Assistant, University of Kassel, FG Computer Architecture & System Programming
• Since 2015: Member in the research project Language Engineering for Multilevel Modelling (LE4MM)

Publications:

• Frank, Ulrich; Töpel, Daniel: Association Types: Motivation, Specification and Implementation with the XModelerML. In: ACM/IEEE 27th International Conference on Model Driven Engineering Languages and Systems (MODELS Companion ’24), September 22–27, 2024, Linz, Austria. 2024. PDFCitationDetails
• Clark, Tony; Frank, Ulrich; Gulden, Jens; Töpel, Daniel: An Extended Concept of Delegation and its Implementation within a Modelling and Programming Language Architecture. In: Enterprise Modelling and Information Systems Architectures. Vol. 19, No. 2 . 2024. doi:10.18417/emisa.19.2 PDFCitationAbstractDetails

  Object-oriented modeling languages provide various concepts to express abstractions, which foster reuse and integrity. Among these concepts, generalization/specialization is of specific relevance. However, in many cases where generalization/specialization seems to be a natural choice, its use is likely to jeopardize a system’s integrity. Delegation has for long been known as an alternative that allows preventing the accidental damage caused by the inproper use of specialization. Nevertheless, delegation is ignored by most tools for object-oriented modeling as well as by many textbooks, which may be caused by the fact that there is no unified conception of delegation, and that delegation is not supported by most object-oriented programming languages. This paper aims at a revival of delegation. To that end, the need for delegation is motivated by the analysis of counter-intuitive effects of specialization. Based on an extensive requirements analysis, a new, extended conception of delegation is presented. It allows for using delegation between classes on any (meta-) level and introduces the "delegation to class" pattern. Delegation in multi-level environments enables an additional reduction of redundancy and, hence, promotes integrity. The paper also presents design guidelines to foster the appropriate use of delegation. With respect to the implementation of delegation with object-oriented programming languages, two alternative flavours of delegation are analyzed. Finally, a prototypical implementation within a language engineering and execution environment does not only demonstrate the use of delegation in a modeling tool, but also its seamless implementation, by featuring a common representation of models and code at runtime.

• Frank, Ulrich; Maier, Pierre; Töpel, Daniel: Modeling Facets of a Warehouse with the FMMLx: A Contribution to the MULTI Warehouse Challenge. In: ACM/IEEE International Conference on Model Driven Engineering Languages and Systems Companion (MODELS-C). 2023, p. 659-668. doi:10.1109/MODELS-C59198.2023.00107PDFCitationDetails
• Lange, Arne; Frank, Ulrich; Atkinson, Colin; Töpel, Daniel: Comparing LML and FMMLx - A contribution to the MULTI Collaborative Comparison challenge. In: ACM/IEEE International Conference on Model Driven Engineering Languages and Systems Companion (MODELS-C). 2023, p. 669-678. doi:10.1109/MODELS-C59198.2023.00108PDFCitationDetails
• Töpel, Daniel; Kaczmarek-Heß, Monika: Towards Flexible Creation of Multi-Level Models - Bottom-Up Change Support in the Modeling and Programming Environment XModeler. In: ACM/IEEE 25th International Conference on Model Driven Engineering Languages and Systems: Companion Proceedings. ACM. 2022. PDFCitationAbstractDetails

  A process of a multi-level model creation follows typically the topdown approach, i.e., it requires first defining concepts and relations on the highest classification levels, which only then can be used to create concepts on the lower ones. Empirical insights into the process of multi-level model creation suggest however, that this strategy may be counter-intuitive and challenging, especially for non-experts. This paper addresses this problem by focusing on the idea of flexible multi-level model creation, understood as an intertwined application of top-down and bottom-up strategies. As a first step towards realizing this vision for multi-level models in general, and those created with the XModeler and Flexible MetaModeling and Execution Language (FMMLx) in particular, in this paper, we select a set of relevant multi-level refactoring patterns, adapt them to our approach, and implement them in the supporting tool. We illustrate the flexible creation process using an exemplary scenario.
   

• Frank, Ulrich; Mattei, Luca; Clark, Tony.; Töpel, Daniel: Beyond Low Code Platforms: The XModelerML - an Integrated Multi-Level Modeling and Execution Environment. In: Michael, J.; Pfeiffer, J.; Wortmann, A. (Ed.): Modellierung 2022 Satellite Events, Digital Library. Gesellschaft für Informatik e.V., 2022, p. 235-244. doi:10.18420/modellierung2022ws-032CitationDetails
• Töpel, Daniel: Associations in Multi-Level-Modelling: Motivation, Conceptualization, Modelling Guidelines, and Implications for Model Management. In: MODELS ’21. Proceedings of the 24th ACM/IEEE International Conference on Model Driven Engineering Languages and Systems: Companion Proceedings. IEEE. 2022. doi:10.1109/MODELS-C53483.2021.00079Full textCitationDetails
• Frank, Ulrich; Töpel, Daniel: Contingent level classes: motivation, conceptualization, modeling guidelines, and implications for model management - Article No.: 86. In: MODELS '20: Proceedings of the 23rd ACM/IEEE International Conference on Model Driven Engineering Languages and Systems: Companion Proceedings. Montreal 2020, p. 1-10. doi:10.1145/3417990.3421413CitationDetails
• Daniel, Töpel: A Perspective Based Level Addressing System for Unbalanced Meta Models. In: 5th International Workshop on Multi-Level Modelling – MULTI 2018. Copenhagen 2018. CitationDetails
• Töpel, Daniel; Benner, Björn: Maintenance of Multi-Level Models - An Analysis of Elementary Change Operations. In: MULTI@ MoDELS, 2017. 2017. Full textCitationDetails