2026 ASEE Annual Conference & Exposition

This paper reports on Year 2 of a Research in Emerging Technologies for Teaching and Learning (RETTL) project focused on threshold concepts in cyber-physical systems (CPSs). Threshold concepts, when mastered, are said to lead to a transformed understanding of the subject – in this case, CPS design – and a shift in the students' identities within the field's context. Given the cruciality of these concepts to a field, not just CPS, the premise of threshold concepts has been used to unpack student misconceptions and design the formative learning experiences necessary for students to master a subject's core ideas. In this project, we are developing a tabletop testbed to learn the core concepts in CPS design, mirroring a smart grid application. We plan to identify which of these concepts constitute threshold concepts within the field, involving both students and engineers in experimenting with the testbed. Expanding our Year 1 activities, which included prototyping a tabletop CPS testbed, conducting a systematic literature review, and initiating a three-round Delphi study with 11 CPS experts, our Year 2 work focuses on advancing and expanding these efforts.

In Year 2, we concentrated our efforts on designing and fabricating an enhanced testbed prototype, successfully developing version 2.0 with significant improvements over its predecessor. This new iteration achieved substantial component miniaturization compared to version 1, while incorporating more sophisticated and realistic functionality. The enhanced design features multi-directional electricity and data flow capabilities, representing a significant advancement in system flexibility. We also implemented an expandable, interconnected network architecture that replaces a limited sequential chain-link design in version 1, allowing for more complex and realistic testing scenarios. Complementing these hardware improvements, we upgraded the software infrastructure and developed a dedicated control application that enables wireless remote access for real-time system monitoring and data collection.

For the educational research part of our project, we completed the Delphi study, which culminated in a set of core concepts to CPS and potential threshold concepts we could explore using the testbed. We refined 65 proposed concepts into 15 high-consensus candidate threshold concepts. Moreover, in anticipation of the testbed's completion, we developed a set of potential model-eliciting activities (MEAs) based on the potential threshold concepts identified in the Delphi study. These activities engage students in developing a model (broadly defined) in response to a real-world scenario that is flexible to changes in the constraints. Although we have our preliminary drafts, the specifics of these activities require consideration of the testbed's capabilities. Thus, as the testbed's precise technical capabilities and details take shape, these MEAs will be further defined.

This paper will provide an overview of the results of the Delphi study and the corresponding MEAs, connecting to the testbed's current and expected functionality. As we move forward in the project, we will integrate our findings from the educational research strand into the testbed development. Collectively, these efforts advance methodological tools for threshold concept research in an interdisciplinary engineering context and inform the design of CPS learning environments that foster transformative learning experiences.