Congratulations Carl Toller Melén, PhD in Mechanical Engineering!
- Post by: Tobias Larsson
- 12th February 2026
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Carl Toller Melén successfully defended his PhD thesis “Effective Simulations for Value Exploration in System-of-Systems Design: A Step Towards Digital Twins” in front of a full crowd of colleagues, family and friends at BTH, and also some 30 people online. The intense long-distance runner made a popular presentation of his research and took the audience through his findings and application cases within mechanical engineering and construction industry, with emphasis on modelling and simulation for informed decision making in quarry operations, and then landed in a summary of his findings.
Carl Toller Melén has focused on simulation-based decision support for System-of-Systems (SoS) design, motivated by the growing complexity of Product-Service System offerings (e.g., transport-as-a-service, power-by-the-hour) where value creation depends on collaboration between multiple systems, stakeholders, and uncertain operational contexts. The thesis systematically investigates how simulations and operational data can be leveraged to explore value creation in early SoS design, introducing two main contributions: (1) the Value–Data Framework, which operationalizes Value-Driven Design by linking hierarchical value models to operational datasets—either physical or synthetic—enabling transparent and quantitative assessment of value creation across multi-stakeholder settings using Group Model Building methods, and (2) an Integrated Simulation Platform that enables design teams to develop effective multi-fidelity SoS simulations in early design stages, explicitly balancing computational complexity against accuracy. Both contributions are demonstrated through quarry industry case studies involving electrification and autonomy scenarios. The thesis further expands the SoS simulation perspective through the lens of Digital Twinning, examining use cases and needs for deploying Digital Twins in climate resilience efforts. Ultimately, the work contributes a methodological foundation for bridging Value-Driven Design and SoS simulations, providing practical guidelines for managing fidelity trade-offs and improved decision support for electrification, autonomy, and resilience strategies.
Carl has worked in a highly collaborative applied research environment throughout his PhD, participating in several research projects: Model Driven Development and Decision Support | 2013-2022 (KKS research profile) | ASPECT – A System for Electric and Connected Transport Solutions | 2021-2024, Future Fossil Free Rock Loading Solution | 2022-2025, TRUST-SOS – TRUSTed – Site Optimisation Solutions | 2021-2024, Tested – SOS | 2024-2027 (Strategic Vehicle Research and Innovation FFI program, funded by VINNOVA) | RESIST – Regions for climate change resilience through Innovation, Science and Technology | 2023-2027 (EU Horizon Europe) with funding from KKS, VINNOVA, and the European Union.
Faculty opponent was Associate Professor Peter Törlind (Luleå University of Technology, Sweden), and the grading committee consisted of Prof. Ben Hicks (University of Bristol, Great Britain), Prof. Gaetano Cascini (Politecnico di Milano, Italy), and Prof. Anna Syberfeldt (University of Skövde, Sweden).
The opponent Peter Törlind then took the stage and invited Carl into a deep conversation around the work he had done and by this creating an interesting back-and-forth “battle” that took the audience through both the motivation of the work, the scientific approach and results, together with the industrial aspects of applied work done by Carl via industrial cases. Quote of the day was probably “So you did the marathon, but then you did the triathlon on the side?” when Peter looked at the role of paper F in the thesis.
After the opponent, grading committee, and audience have had the chance to bring up their questions, the grading committee left the room for their discussion and eventually returned with the verdict; a pass!
We gratulate our newest PhD on an important milestone in his career, and future success!
Abstract
Today, increased global competition and regulatory demands push organizations to find innovative ways to design and create value. One way is to examine Product-Service System offerings, which enable more stable revenues and foster tighter collaboration and value co-creation between the provider and customer. However, this often means adopting a System-of-Systems (SoS) approach where the value creation is dependent on successful collaboration between constituent systems and actors. SoS also leads to higher complexity and uncertainty, making them more challenging to design, especially in the early stages where knowledge is limited. Therefore, this thesis investigates how to leverage simulations and operational data to explore the value creation in SoS design.
Methodologically, the work adopts a Design Research Methodology and Participatory Action Research approach, combining systematic literature reviews with six industrial case studies in the construction machinery and climate resilience sectors. The case studies originate from a series of research projects conducted in collaboration with various industrial and public partners between 2020 and 2025.
The research introduces two main contributions. First, the Value–Data Framework, which operationalizes Value-Driven Design by linking value modeling to operational datasets, enabling transparent and quantitative assessment of value creation. The value model introduces a two-step value hierarchy to enhance transparency and address the growing complexity of SoS. Operational data is defined and classified clearly to show where and how it can be leveraged. The second contribution, an Integrated Simulation Platform, equips design teams with the ability to develop effective simulations for SoS modeling in early design stages. The platform explicitly addresses multi-fidelity to guide developers in balancing the computational complexity and accuracy. Finally, both contributions are demonstrated in quarry case studies to validate and highlight their usefulness. Lastly, the SoS simulations are contextualized for Digital Twinning, and the use cases and needs for deploying Digital Twins in climate resilience efforts are examined.
The findings advance theory by bridging Value-Driven Design and SoS simulations, and provide practical guidelines for managing fidelity trade-offs and data–value integration. Industrial implications include improved decision support for electrification, autonomy, and resilience strategies.
Keywords: System-of-Systems, Value-Driven Design, Operational data, Simulation, Decision support, Digital Twin
Download full thesis here: https://urn.kb.se/resolve?urn=urn:nbn:se:bth-28936
The presentation part of the PhD defense session
Spotify Podcast episode on the PhD thesis
More information
- “Simulering visar vägen till bättre beslut” (BTH Press 20260210)
- Congratulations Carl Toller Melén, Licentiate in Mechanical Engineering!
- “Simuleringar visar vägen till bättre beslut” (Grönt Samhällsbyggande 20260210)