Publications
Journal Articles
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Effects of Functional and Declarative Modeling Frameworks on System Simulation
John Morris, Gregory Mocko, John Wagner
Jan 2026 | J. Dyn. Sys., Meas., Control
System modeling frameworks can be categorized into imperative and declarative paradigms. Which paradigm a model is expressed in effects how the model may be utilized; imperative models allow simple execution, while declarative models capture the behavior of the underlying system. This paper compares these paradigms, as well as functional and object-oriented frameworks, in light of physics-based systems. This is done by exploring the principles of systems modeling and simulation. Simulation is shown to be the composition of functions representing system behavior. Simulatable frameworks can be differentiated by their ability to identify and compose these functions for a specific input and output pairing. The various frameworks are explored, applying concepts more typically studied in computer science to general systems engineering. The frameworks are investigated by comparing simulations of a driven double pendulum in various modeling languages. Observations include that functional, declarative models allow for greater reusability and holistic system simulation.
@article{morrisDeclarativeSimulationJDSMC2025,
title = {Effects of {{Functional}} and {{Declarative Modeling Frameworks}} on {{System Simulation}}},
author = {Morris, John and Mocko, Gregory and Wagner, John},
date = {2026-01},
journaltitle = {J. Dyn. Sys., Meas., Control},
publisher = {ASME},
doi = {10.1115/1.4070883},
}
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ConstraintHg: A Kernel for Systems Modeling and Simulation
John Morris
Jan 2026 | Journal of Open-Source Software
ConstraintHg is a systems modeling kernel used for parsing constraint hypergraphs. Constraint hypergraphs are a mathematical formalism embodying the constraint-based approach to representing behavior. Any executable model--whether database schema, plant controller, or ecological forecaster--can be represented as a constraint hypergraph. Once combined, the unified structure shows how all elements in the system are related to each other. In addition to representing constraint hypergraphs, ConstraintHg provides methods for traversing them, equivalent to simulating the system. While most system simulations must be imperatively defined, ConstraintHg enables simulations to be constructed declaratively. As a result, knowledge about a system can be discovered autonomously, transforming a general system representation into an agentic information provider.
@article{morrisConstraintHgJOSS,
title = {{{ConstraintHg}}: {{A Kernel}} for {{Systems Modeling}} and {{Simulation}}},
author = {Morris, John},
date = {2026-01-19},
journaltitle = {Journal of Open-Source Software},
volume = {11},
number = {117},
pages = {9131},
publisher = {Open Journals},
issn = {2475-9066},
doi = {10.21105/joss.09131},
}
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Digital Engineering Education Challenges and Opportunities–A Case Study in a Mechanical Engineering Senior Capstone Design Course
Frederick Rowell, John Morris, Todd Schweisinger, John Wagner
Oct 2025 | In press with Intl. J. of Product Lifecycle ManagementProduct lifecycle management (PLM) concepts and software are inextricably intertwined into product design and manufacturing enterprises. Despite its common applications in engineering industries, many mechanical engineering programs have not integrated PLM software into their curriculums. The PLM Center at Clemson University has worked to bring PLM workshops and research opportunities to mechanical engineering students but has not maintained high outreach because those opportunities are not required for all students. Different areas of the standard mechanical engineering curriculum were analyzed for PLM integration, with the senior capstone design course identified as the ideal location for implementation. Two case studies were conducted with senior capstone design classes to determine the effects of utilizing an integrated computer-aided design (CAD) and product data management (PDM) system to increase product quality, collaboration, and design efficiency, as well as understand the challenges with integrating PLM software into a required course in the Bachelor of Science in Mechanical Engineering (BSME) curriculum. Student teams in a small-scale wind turbine design project initially utilized the PLM system for the design of their turbine blades, but eventually decided to stop using the software for the rest of the project because of the large learning curve for the software and short time frame the project must be completed in. Student teams in a drag force measurement tool design project used the PLM system for the entire semester to assist in their design process but created a less-successful product compared to teams that did not use the software. Both case studies revealed real and perceived obstacles to PLM integration into the BSME curriculum, while identifying potential rewards for overcoming those barriers. A grand challenge to the PLM community is issued to ease the obstacles facing PLM concepts and tools integration into engineering education.
@article{rowellDigitalEngineeringEducation2025,
title = {Digital {{Engineering Education Challenges}} and {{Opportunities}}–{{A Case Study}} in a {{Mechanical Engineering Senior Capstone Design Course}}},
author = {Rowell, Frederick and Morris, John and Schweisinger, Todd and Wagner, John},
date = {2025-10},
journaltitle = {In press with Intl. J. of Product Lifecycle Management},
publisher = {Inderscience Publishers},
}
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Unified System Modeling and Simulation via Constraint Hypergraphs
John Morris, Gregory Mocko, John Wagner
Apr 2025 | J. Comput. Inf. Sci. Eng.
This paper describes the theory behind constraint hypergraphs: a novel modeling framework that can be used to universally represent and simulate complex systems. Multi-domain system models are traditionally compiled from many diverse frameworks, each based in a single domain. Incompatibilities between these frameworks prevent information from being shared resulting in data silos, duplicate work, and knowledge gaps. A constraint hypergraph addresses these problems by providing a universal modeling framework within which all model prescriptions can be expressed. This methodology expands mathematical structures previously explored in abstract mathematics and systems theory into a new executable framework. Each hypergraph expresses the holistic behavior of a system in a declarative paradigm that describes the relationships between system properties. In addition to modeling, it is shown how constraint hypergraphs can be used for universal, cross-cutting simulation through principles of function composition. The theoretical framework of a constraint hypergraph is demonstrated with a practical representation of a hybrid system, combining a discrete-event simulation and continuous PID controller into a single model of an elevator lift system.
@article{morrisUnifiedSystemModeling2025,
title = {Unified {{System Modeling}} and {{Simulation}} via {{Constraint Hypergraphs}}},
author = {Morris, John and Mocko, Gregory and Wagner, John},
date = {2025-04-04},
journaltitle = {J. Comput. Inf. Sci. Eng.},
volume = {25},
number = {6},
pages = {061005},
doi = {10.1115/1.4068375},
langid = {english},
Special Issue on Networks and Graphs for Engineering Systems and Design}
}
Submitted Journal Articles
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Declarative, Multi-physics Simulation Between Applications via Constraint Hypergraphs
John Morris, Abhishek Indupally, Gregory Mocko, John Wagner, Satchit Ramnath
Oct 2025 | Under review with J. Comput. Inf. Sci. Eng.To avoid the blind spots and brittleness of imperatively simulating a physical system, modelers often turn to declarative methods that can autonomously execute a model. Such solvers rely on a model structure that allows procedures for transforming inputs to outputs to be automatically discovered. However, the model structures used for traditional declarative solvers are insular, in that they are often isolated to specific modeling domain. Furthermore, these specific model types are unable to be understood by the advanced computing applications required to simulate complex systems. Here we provide a general purpose modeling framework that can integrate software functionalities into the declarative simulation of a model, offering for the first time the ability to define a multi-physics, multi-scale system independent of its eventual simulation. This is accomplished by representing a system as a constraint hypergraph. System models are deconstructed into state variables and relationships in the graph. The APIs of external tools are integrated into the model as inter-variable functions. By encoding these functionalities in the graph, a solver is able to autonomously arrange these relations into executable simulation processes, enabling fully declarative simulation. This is demonstrated by integrating the capabilities of three software platforms together into a single model of a crankshaft from a piston engine: solid geometry (Onshape), structural mechanics (Ansys Mechanical), and kinematic analysis (MATLAB). The result is a holistic modeling framework that allows for flexible simulation of a complex system, integrates directly with otherwise sequestered platforms, and reveals cross-cutting interactions between system elements.
@article{morrisDeclarativeIntegrationEngineering2025,
title = {Declarative, {{Multi-physics Simulation Between Applications}} via {{Constraint Hypergraphs}}},
author = {Morris, John and Indupally, Abhishek and Mocko, Gregory and Wagner, John and Ramnath, Satchit},
date = {2025-10},
journaltitle = {Under review with J. Comput. Inf. Sci. Eng.},
publisher = {ASME},
}
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Constraint Hypergraphs as a Unifying Framework for Digital Twins
John Morris, Edward Louis, Douglas L. Van Bossuyt, Gregory Mocko, John Wagner
Jul 2025 | Under review with Systems Journal
Digital twins, used to represent physical systems, have been lauded as tools for understanding reality. Complex system behavior is typically captured in domain-specific models crafted by subject experts. Contemporary methods for employing models in a digital twin require prescriptive interfaces, resulting in twins that are difficult to connect, redeploy, and modify. The limited interoperability of these twins has prompted calls for a universal framework enabling observability across model aggregations. Here we show how a new mathematical formalism called a constraint hypergraph serves as such a framework by representing system behavior as the composition of set-based functions. A digital twin is shown to be the second of two coupled systems where both adhere to the same constraint hypergraph, permitting the properties of the first to be observable from the second. Interoperability is given by deconstructing models into a structure enabling autonomous, white-box simulation of system properties. The resulting digital twins can interact immediately with both human and autonomous agents. This is demonstrated in a case study of a microgrid, showing how both measured and simulated data from the aggregated twins can be provided regardless of the operating environment. By connecting models, constraint hypergraphs supply scientists and modelers robust means to capture, communicate, and combine digital twins across all fields of study. We expect this framework to expand the use of digital twins, enriching scientific insights and collaborations by providing a structure for characterizing complex systems.
@article{morrisConstraintHypergraphsUnifying2025,
title = {Constraint {{Hypergraphs}} as a {{Unifying Framework}} for {{Digital Twins}}},
author = {Morris, John and Louis, Edward and Van Bossuyt, Douglas L. and Mocko, Gregory and Wagner, John},
date = {2025-07},
journaltitle = {Under review with Systems Journal},
publisher = {IEEE},
doi = {10.48550/arXiv.2507.05494},
langid = {english},
https://doi.org/10.48550/arXiv.2507.05494}
}
Conference Articles
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From Knowledge Graphs to Constraint Hypergraphs
Joe Gregory, John Morris
Jun 2026 | IS 2026As systems engineering increasingly depends on digital models and integrated data environments, the graph representation of engineering knowledge has become a key enabler of semantic consistency, traceability, and automation. To implement this, we may use ontology languages such as the Web Ontology Language (OWL2DL) and the Ontological Modeling Language (OML) to define the concepts and relations within our domain, and then use logical reasoners to infer new information and detect inconsistent, incomplete or incorrect information. However, a limitation of purely logical representations is their inability to perform mathematical reasoning. Logical inference can identify missing or inconsistent facts, but it cannot compute or optimize quantitative parameters that drive engineering analyses. This paper presents the development of an approach that bridges this gap by generating solvable constraint hypergraphs (CHGs) in an executable format from knowledge graphs (KGs) that capture systems engineering knowledge. Ontologies provide the formal semantics of the relevant domains, while data instances populate those models with project-specific information. From this structured knowledge, mathematical relations among parameters are automatically identified and transformed into a CHG representation in which nodes represent quantities and hyperedges represent the mathematical relations between them. In this paper, we describe an end-to-end workflow from ontological modeling and data integration to constraint extraction and solution, and we demonstrate its application through a spacecraft design example. In this example, a KG describing a spacecraft and its environment is used to automatically generate the mathematical relations that describe power, mass, and communication performance. The resulting constraint hypergraph is then solved to derive consistent parameter values across the system model. By translating logical relations into executable constraint structures, this approach enables automated numerical reasoning without compromising semantic rigor. It reduces the risk of inconsistencies when defining equations manually and strengthens the integration between logical and analytical representations within digital engineering enviroinments.
@inproceedings{gregoryIS2026_paper_3922026,
title = {From {{Knowledge Graphs}} to {{Constraint Hypergraphs}}},
booktitle = {Submitted to 36th {{Annual INCOSE International Symposium}}},
author = {Gregory, Joe and Morris, John},
date = {2026-06-13},
publisher = {INCOSE},
location = {Yokohoma, Japan},
eventtitle = {{{IS}} 2026},
}
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Technical Strategies for Semantic Aggregation of Interoperable Digital Twins
John Morris, Duncan Gibbons, Joe Gregory, Gregory Mocko
Apr 2026 | CSER26Digital twin aggregates are a synchronized representation of a real system formed by the composition of multiple subsystem models. When formed in an interoperable manner, the integrated models should reveal the emergent behavior of the greater system. The ability to combine independently developed digital twins is a critical aspect of democratized modeling, however, no methods currently enable universal aggregation. In this paper, we propose a two-pronged approach to solving model interoperability that addresses both behavioral and interpretive aspects of describing supersystems. The first prong employs a constraint hypergraph to capture the relationships between system information; we show that these hypergraphs can be autonomously extended given the satisfaction of certain properties. Extended relationships between the joined hypergraphs reveal emergent behaviors, while non-modeled phenomena are contraindicated. The interpretation of the twin aggregate is given descriptively using SysML, which uses external frames of reference to contextualize the system properties. Limitations include having to trade generality in representing the specific aggregated system. Exploring strategies such as these permit models to be connected autonomously even without a prespecified context, allowing modeling experts to focus on specific subdomains of a problem with guaranteed model compatibility.
@inproceedings{morrisInteroperabilityCSER2026,
title = {Technical {{Strategies}} for {{Semantic Aggregation}} of {{Interoperable Digital Twins}}},
booktitle = {Submitted to {{Conference}} on {{Systems Engineering Research}}},
author = {Morris, John and Gibbons, Duncan and Gregory, Joe and Mocko, Gregory},
date = {2026-04-06},
publisher = {INCOSE},
location = {Arlington, VA, USA},
eventtitle = {{{CSER26}}},
}
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Effects of Functional and Declarative Modeling Frameworks on System Simulation
John Morris, Gregory Mocko, John Wagner
Oct 2025 | The 5th Modeling, Estimation and Control Conference (MECC 2025)System modeling frameworks can be categorized into imperative and declarative paradigms. Which paradigm a model is expressed in effects how the model may be utilized; imperative models allow simple execution, while declarative models capture the behavior of the underlying system. This paper compares these paradigms, as well as functional and object-oriented frameworks, in light of physics-based systems. This is done by exploring the principles of systems modeling and simulation. Simulation is shown to be the composition of functions representing system behavior. Simulatable frameworks can be differentiated by their ability to identify and compose these functions for a specific input and output pairing. The various frameworks are explored, applying concepts more typically studied in computer science to general systems engineering. The frameworks are investigated by comparing simulations of a driven double pendulum in various modeling languages. Observations include that functional, declarative models allow for greater reusability and holistic system simulation.
@inproceedings{morrisEffectsFunctionalDeclarative2025,
title = {Effects of {{Functional}} and {{Declarative Modeling Frameworks}} on {{System Simulation}}},
author = {Morris, John and Mocko, Gregory and Wagner, John},
date = {2025-10-07},
publisher = {IFAC},
location = {Pittsburgh, PA},
eventtitle = {The 5th {{Modeling}}, {{Estimation}} and {{Control Conference}} ({{MECC}} 2025)},
}
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Declarative Integration of CAD Software into Multi-Physics Simulation via Constraint Hypergraphs
John Morris, Gregory Mocko, John Wagner, Satchit Ramnath
Aug 2025 | ASME IDETC-CIE 2025
Declarative modeling frameworks, such as Modelica, are often used to represent systems that require reusable and interoperable models. Simulation in such a framework requires a solver that is capable of transforming the model into an executable process. However, most declarative solvers are insular, in that they are unable to integrate with software applications needed for simulating complex systems, limiting their usability for simulating multi-domain models. This paper describes a process for creating declarative models that can integrate with an external tool by deconstructing its Application Programmer Interface (API) into a set of functions arranged into a constraint hypergraph. The constraint hypergraph's solver is shown to be capable of automatically parsing these functions to simulate arbitrary pairs of inputs and outputs. The result is a holistic modeling framework that allows for flexible simulation of a complex system, integrates directly with otherwise sequestered platforms, and reveals cross-cutting interactions between system elements. This is demonstrated by integrating the solid modeling capabilities of Onshape with a dynamic model of a crankshaft from a piston engine, showing how a geometric model can be integrated with independently-defined dynamic models. This validates the framework on a limited scale, setting the foundation for work for fully integrating disparate tools into multi-domain, multi-physics modeling and simulation.
@inproceedings{morrisDeclarativeIntegrationCAD2025,
title = {Declarative {{Integration}} of {{CAD Software}} into {{Multi-Physics Simulation}} via {{Constraint Hypergraphs}}},
booktitle = {Proceedings of the {{ASME}} 2025 {{International Design Engineering Technical Conferences}} and {{Computers}} and {{Information}} in {{Engineering Conference}}},
author = {Morris, John and Mocko, Gregory and Wagner, John and Ramnath, Satchit},
date = {2025-08-17/2025-08-20},
volume = {2A: 45th Computers and Information in Engineering Conference (CIE)},
publisher = {ASME},
doi = {10.1115/DETC2025-168376},
eventtitle = {{{ASME IDETC-CIE}} 2025},
isbn = {978-0-7918-8920-6},
}
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Dynamic Estimator of CAD Patterning Feature Execution Time
John Morris, Dave Procopio, John Wagner
Nov 2023 | ASME IDETC-CIE 2023
Tool for predicting the execution time necessary to construct a large solid geometry pattern using various methods in NX.
@inproceedings{morrisDynamicEstimatorCAD2023,
title = {Dynamic {{Estimator}} of {{CAD Patterning Feature Execution Time}}},
booktitle = {Proceedings of the {{ASME}} 2023 {{International Design Engineering Technical Conferences}} and {{Computers}} and {{Information}} in {{Engineering Conference}}},
author = {Morris, John and Procopio, Dave and Wagner, John},
date = {2023-11-21},
publisher = {ASME},
location = {Boston, MA},
url = {https://github.com/Clemson-PLMC/PatternEstimatorTool},
urldate = {2024-06-19},
eventtitle = {{{ASME IDETC-CIE}} 2023},
}
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Evaluation of CAE Design Change Updates--A Case Study on Gas Turbine Airflow Disruptors
David Procopio, John Morris, John Wagner
Nov 2023 | ASME IDETC-CIE 2023
Abstract. The rapid growth of digitalization in design and advanced manufacturing, characterized by computer tools, has emphasized software tools throughout the process. To compete in the global marketplace, companies need to embrace virtual design and digital manufacturing methods. Computer-aided design and computer-aided engineering embody the workflow process and tools to bring forth products from conception to design, where detailed changes can be made to fabricate the product efficiently in the manufacturing phase. This paper examines three CAD/CAE patterning features used in Siemens NX on the design of gas turbine turbulators — internal turbine blade surface discontinuities that enhance the heat transfer between the cooling air and blades on whose outside surface are subject to hot combustion gases. Each patterning feature is used to produce a pattern with a high number of instances on a variety of surfaces. The simulations’ execution speed, memory usage, versatility, and integrity of the produced model is evaluated to quantify the performance of the three features. The global pandemic and supply chain challenges has shown the need for virtual modeling and engineering design platforms to efficiently complete complex projects and patterning methods applicable when replicating elements.
@inproceedings{procopioEvaluationCAEDesign2023,
title = {Evaluation of {{CAE Design Change Updates--A Case Study}} on {{Gas Turbine Airflow Disruptors}}},
booktitle = {Proceedings of the {{ASME}} 2023 {{International Design Engineering Technical Conferences}} and {{Computers}} and {{Information}} in {{Engineering Conference}}},
author = {Procopio, David and Morris, John and Wagner, John},
date = {2023-11-21},
publisher = {American Society of Mechanical Engineers Digital Collection},
doi = {10.1115/DETC2023-116761},
eventtitle = {{{ASME IDETC-CIE}} 2023},
langid = {english},
}
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Application of Extracurricular Course Teaching Product Lifecycle Management Concepts to Undergraduates
John Morris, John R. Wagner
Jun 2023 | 2023 ASEE Annual Conference & Exposition
Extended, project-based activities are critical for preparing undergraduate students for roles in modern industry yet are often difficult to provide through traditional curricula. This practice paper describes the objectives and functions of a student-centric research endeavor within the Clemson University Creative Inquiry framework that provides guided instruction and extracurricular experiences on product lifecycle management (PLM). The course objective is to develop a digital twin for a scaled, tracked, robotic vehicle while introducing participants to PLM topics and tools. Due to its breadth, this project incorporates activities such as collaborative design and project management, while providing hands on experiences with computer aided (CAx) tools, organizational documentation, and additive manufacturing. Relatedly, students are empowered to explore PLM topics of individual interest, gaining insight into the digitalization of STEM fields. Observed challenges include participant turnover and maintaining the relevancy of the project through strategic updates. The course showcases the value of extracurricular projects in preparing undergraduate students for successful roles in industry.
@inproceedings{morrisApplicationExtracurricularCourse2023,
title = {Application of {{Extracurricular Course Teaching Product Lifecycle Management Concepts}} to {{Undergraduates}}},
author = {Morris, John and Wagner, John R.},
date = {2023-06-25},
location = {Baltimore, MD},
doi = {10.18260/1-2--42269},
eventtitle = {2023 {{ASEE Annual Conference}} \& {{Exposition}}},
}
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Application of Product Lifecycle Management in the University Classroom and Laboratory
David Procopio, John Morris, John R. Wagner
Jun 2023 | 2023 ASEE Annual Conference & Exposition
Despite widespread acknowledgement of PLM technologies’ pivotal role in supporting modern industry, undergraduate STEM programs often struggle to include instruction on PLM topics due to the difficulty of covering the preponderance of discipline-specific concepts inherent in traditional curricula within the allocated credit hours. This paper discusses the establishment and operation of a new center at with directives to prepare collegiate students in utilizing PLM technologies through a variety of extracurricular activities and PLM resources. These include short-course lectures, guided software workshops, semester-length projects, support for research activities, and provision of PLM software in an open-access computer lab. To access the effectiveness of these educational efforts, the analysis of student surveys can help to tailor the activities to better meet learning needs. This model of supporting traditional curricula with extracurricular activities shows potential in preparing students for career roles driven by modern, digital processes.
@inproceedings{procopioApplicationProductLifecycle2023,
title = {Application of {{Product Lifecycle Management}} in the {{University Classroom}} and {{Laboratory}}},
author = {Procopio, David and Morris, John and Wagner, John R.},
date = {2023-06-25},
location = {Baltimore, MD},
doi = {10.18260/1-2--42669},
eventtitle = {2023 {{ASEE Annual Conference}} \& {{Exposition}}},
}
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Usefulness and Time Savings Metrics to Evaluate Adoption of Digital Twin Technology
Conner Eddy, Matthew Castanier, John Wagner, John Morris, Benjamin Moss
Jan 2023 | WCX SAE World Congress Experience
The application of virtual engineering methods can streamline the product design process through improved collaboration opportunities among the technical staff and facilitate additive manufacturing processes. A product digital twin can be created using the available computer-aided design and analytical mathematical models to numerically explore the current and future system performance based on operating cycles. The strategic decision to implement a digital twin is of interest to companies, whether the required financial and workforce resources will be worthwhile. In this paper, two metrics are introduced to assist management teams in evaluating the technology potential. The usefulness and time savings metrics will be presented with accompanying definitions. A case study highlights the usefulness metric for the “Deep Orange” prototype vehicle, an innovative off-road hybrid vehicle designed and fabricated at Clemson University. Survey responses identified factors including verification/validation and model organization as critical focus areas for future digital twin technology implementation. The results demonstrate how model repertoires can be leveraged to new product cycles and fill the knowledge gaps of new engineers joining the development team. Overall, the metrics establish a basis to generate discussions regarding embracing emerging workplace technology.
@inproceedings{eddyUsefulnessTimeSavings2023,
title = {Usefulness and {{Time Savings Metrics}} to {{Evaluate Adoption}} of {{Digital Twin Technology}}},
author = {Eddy, Conner and Castanier, Matthew and Wagner, John and Morris, John and Moss, Benjamin},
date = {2023-01-24},
pages = {14},
publisher = {SAE International},
doi = {10.4271/2023-01-0111},
eventtitle = {{{WCX SAE World Congress Experience}}},
langid = {english},
}
In Progress
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Product Lifecycle Management: Processes for Modern Industry
John Morris, John Wagner, Gregory Mocko
Aug 2026 | Intended for publication by Taylor and Francis@book{morrisProductLifecycleManagement2026,
title = {Product {{Lifecycle Management}}: {{Processes}} for {{Modern Industry}}},
author = {Morris, John and Wagner, John and Mocko, Gregory},
date = {2026-08},
publisher = {{Intended for publication by Taylor and Francis}},
}
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Definitions, Methods, and Paradigms of Digital Twin Interoperability
John Morris, Xiaoxue Shen, Joe Gregory, Duncan Gibbons, Matthew Bonney, Douglas L. Van Bossuyt, David Wagg, Gregory Mocko
Mar 2026 | Intended for submission to Wiley Systems EngineeringA comprehensive review of the definitions, paradigms, and methods for making interoperable digital twins, conducted with a globally-based set of digital twin experts.
@article{morrisReviewDigitalTwin,
title = {Definitions, {{Methods}}, and {{Paradigms}} of {{Digital Twin Interoperability}}},
author = {Morris, John and Shen, Xiaoxue and Gregory, Joe and Gibbons, Duncan and Bonney, Matthew and Van Bossuyt, Douglas L. and Wagg, David and Mocko, Gregory},
date = {2026-03},
journaltitle = {Intended for submission to Wiley Systems Engineering},
}
-
Strategies for Technical Composition of Digital Twins
John Morris, Joe Gregory, Duncan Gibbons, Gregory Mocko
Feb 2026 | Intended for submission to Software and Systems ModelingDigital twin aggregates are a synchronized representation of a real system formed by the composition of multiple subsystem models. When formed, the collection of individual models reveals the emergent behavior of the greater system. The ability to combine independently developed digital twins is a critical aspect of democratized modeling, however, no methods currently enable universal aggregation. In this article we propose a two-pronged approach to solving model interoperability that addresses both behavioral and interpretive aspects of describing supersystems. The first prong employs a constraint hypergraph to capture the relationships between system information; we show that these hypergraphs can be autonomously extended given the satisfaction of certain properties. Extended relationships between the joined hypergraphs reveal emergent behaviors, while non-modeled phenomena are contraindicated. The interpretation of the twin aggregate is given ontologically, with a translator between a diagrammatic specification and the simulatable constraint hypergraph able to be automatically generated. These solutions permit models to be connected autonomously without requirements for a specific context or interface, allowing modeling experts to focus on specific subdomains of a problem with guaranteed model compatibility.
@article{morrisDTComposition2025,
title = {Strategies for {{Technical Composition}} of {{Digital Twins}}},
author = {Morris, John and Gregory, Joe and Gibbons, Duncan and Mocko, Gregory},
date = {2026-02},
journaltitle = {Intended for submission to Software and Systems Modeling},
}
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What Is Fidelity Anyways: A Systemized, Conceptual Review
Evan Taylor, Meredith Sutton, Edward Louis, John Morris, Gregory Mocko
Jan 2026 | Intended for submission to Simulation@article{taylorWhatFidelityAnyways,
title = {What Is {{Fidelity Anyways}}: A {{Systemized}}, {{Conceptual Review}}},
author = {Taylor, Evan and Sutton, Meredith and Louis, Edward and Morris, John and Mocko, Gregory},
journaltitle = {Intended for submission to Simulation},
}
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Dealing with Hallucinations: Technical Strategies for Deterministic AI
John Morris, Evan Taylor, Gregory Mocko, John Wagner
Dec 2025 | Intended for submission to Artificial Intelligence Journal@article{morrisDealingHallucinationsTechnical2025,
title = {Dealing with {{Hallucinations}}: {{Technical Strategies}} for {{Deterministic AI}}},
author = {Morris, John and Taylor, Evan and Mocko, Gregory and Wagner, John},
date = {2025-12},
journaltitle = {Intended for submission to Artificial Intelligence Journal},
}
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Methods for Enhancing Tradespace Exploration by Integrating Multi-Scale Simulation
John Morris, Abheek Chatterjee, Meredith Sutton, Douglas L. Van Bossuyt, Astrid Layton, Gregory Mocko
Dec 2025 | Intended for submission to Multiscale Modeling and SimulationThe decision-making power of TSE is improved when the TS is generated by a CHG.
@article{morrisMethodsEnhancingTradespace2025,
title = {Methods for {{Enhancing Tradespace Exploration}} by {{Integrating Multi-Scale Simulation}}},
author = {Morris, John and Chatterjee, Abheek and Sutton, Meredith and Van Bossuyt, Douglas L. and Layton, Astrid and Mocko, Gregory},
date = {2025-12},
journaltitle = {Intended for submission to Multiscale Modeling and Simulation},
}
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Agentic Selection of Valid Multi-Fidelity Models
Evan Taylor, John Morris, Gregory Mocko
Dec 2025 | Intended for submission to J. Comput. Inf. Sci. Eng.Models are tools for inference about the real world. By hitting a button, a facsimile of the real world is ready at our fingertips, ready for analysis and prototyping. However, how do we know that we are using our tools correctly? The effect of making decisions of unverified data and models can be catastrophic in Digital Engineering practice. Passive documentation is not enough, as it requires constant referencing, updating, and compliance of engineers in a fast-paced information age. To make sure that models are used correctly, we must move past passive documentation towards an active decision process using this information. In line with authoritative source of truth standards, decisions about model use should actively feature all of the information we have captured in the real world. This paper proposes a methodology for creating an Authoritative Source of Truth explicitly within the logic of a model, using a new functional modeling methodology, Constraint Hypergraphs (CH). Constraint Hypergraphs provide a unique view of how models can work, by flexibly representing the relationships in the model in an executable manner. These models have the capability of self-referencing, in which the viability of certain paths and the weights of the edges can be changed based values of executed nodes. These facts can then be leveraged for dynamic, traceable, and automated validity frame enforcement and model selection. This methodology ensures that (1) models are being properly used (2) documentation of the model is smoothly integrated in the model itself and (3) the models are optimized to desired standards.
@article{taylorModelSwitching,
title = {Agentic {{Selection}} of {{Valid Multi-Fidelity Models}}},
author = {Taylor, Evan and Morris, John and Mocko, Gregory},
date = {2025-12},
journaltitle = {Intended for submission to J. Comput. Inf. Sci. Eng.},
}
Presentations
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Universal System Simulation via Hypergraphs
Jan 2026 | Invited Research Seminar at East Tennessee State University@unpublished{morrisETSU2026,
type = {Invited Presentation},
title = {Universal {{System Simulation}} via {{Hypergraphs}}},
author = {Morris, John},
date = {2026-01-12},
eventtitle = {Invited {{Research Seminar}} at {{East Tennessee State University}}},
venue = {Johnson City, TN},
}
-
Effects of Functional and Declarative Modeling Frameworks on System Simulation
Oct 2025 | The 5th Modeling, Estimation and Control Conference (MECC 2025)@unpublished{morrisEffectsFunctionalDeclarative2025a,
title = {Effects of {{Functional}} and {{Declarative Modeling Frameworks}} on {{System Simulation}}},
author = {Morris, John},
date = {2025-10-07},
eventtitle = {The 5th {{Modeling}}, {{Estimation}} and {{Control Conference}} ({{MECC}} 2025)},
langid = {english},
venue = {Pittsburgh, PA},
}
-
Universal System Simulation via Hypergraphs Graduate Travel Grant Awardee
Jun 2025 | Applied Category Theory Conference (ACT 2025)@unpublished{morrisACT2025,
title = {Universal {{System Simulation}} via {{Hypergraphs}}},
author = {Morris, John},
date = {2025-06-02},
eventtitle = {Applied {{Category Theory Conference}} ({{ACT}} 2025)},
venue = {Gainesville, FL},
}
-
Solving Interoperability with Digital Twins
Apr 2025 | Guest Presentation to the National Institute for Standards and TechnologyA lack of interoperability is one of the major factors inhibiting digital twins from being used in general industry. Digital twins are nearly always insular creations: composed of bespoke models in siloed platforms. We provide an alternative formalism for reconstructing otherwise sequestered models into a single, unified system model. This mathematical structure is graphical in nature; nodes represent the identifiable states of a system, and edges represent their relationships as functional constraints. This reduces a system to a collection of independent, set-based functions whose arrangement describes the emergent behavior of the system. Several interesting results develop from this. First, the composability of functions guarantees that models can interface with other models without contradiction, allowing digital twins to be formed by model aggregation. Second, universal simulation of the system can be conducted using simple pathfinding strategies, exposing all modeled information about the represented system to an interfacing agent. Applications to digital twins are demonstrated by integrating information from often disparate domains such as discrete-event simulations, controller protocols, relational databases, dynamic models, and CAD tools. In each case, the framework expands the ability for digital twins to communicate information about the real-world systems they represent.
@unpublished{morrisSolvingInteroperabilityDigital2025,
type = {Invited Presentation},
title = {Solving {{Interoperability}} with {{Digital Twins}}},
author = {Morris, John},
date = {2025-04-16},
eventtitle = {Guest {{Presentation}} to the {{National Institute}} for {{Standards}} and {{Technology}}},
venue = {Virtual},
}
-
Model-Based Engineering of Digital Twins Best Poster, Virtual Protyping and Design
Feb 2025 | VIPR-GS Research Center Annual Review Meeting@unpublished{morrisModelBasedEngineeringDigital2025,
type = {Poster},
title = {Model-{{Based Engineering}} of {{Digital Twins}}},
author = {Morris, John},
date = {2025-02-26},
eventtitle = {{{VIPR-GS Research Center Annual Review Meeting}}},
venue = {Greenville, SC},
}
-
Representing Digital Twins Buzz Award Finalist
Aug 2024 | ASME IDETC-CIE: SciTechBuzz Summit 2024@unpublished{morrisRepresentingDigitalTwins2024,
title = {Representing {{Digital Twins}}},
author = {Morris, John},
date = {2024-08-26},
eventtitle = {{{ASME IDETC-CIE}}: {{SciTechBuzz Summit}} 2024},
venue = {Washington DC},
}
-
Application of Extracurricular Course Teaching Product Lifecycle Management Concepts to Undergraduates Graduate Travel Grant Awardee
Aug 2023 | 2023 ASEE Annual Conference & ExpositionExtended, project-based activities are critical for preparing undergraduate students for roles in modern industry yet are often difficult to provide through traditional curricula. This practice paper describes the objectives and functions of a student-centric research endeavor within the Clemson University Creative Inquiry framework that provides guided instruction and extracurricular experiences on product lifecycle management (PLM). The course objective is to develop a digital twin for a scaled, tracked, robotic vehicle while introducing participants to PLM topics and tools. Due to its breadth, this project incorporates activities such as collaborative design and project management, while providing hands on experiences with computer aided (CAx) tools, organizational documentation, and additive manufacturing. Relatedly, students are empowered to explore PLM topics of individual interest, gaining insight into the digitalization of STEM fields. Observed challenges include participant turnover and maintaining the relevancy of the project through strategic updates. The course showcases the value of extracurricular projects in preparing undergraduate students for successful roles in industry.
@unpublished{morrisApplicationExtracurricularCourse2023a,
title = {Application of {{Extracurricular Course Teaching Product Lifecycle Management Concepts}} to {{Undergraduates}}},
author = {Morris, John},
date = {2023-08-01},
eventtitle = {2023 {{ASEE Annual Conference}} \& {{Exposition}}},
venue = {Baltimore, MD},
}
-
Application of Product Lifecycle Management in the University Classroom and Laboratory Graduate Travel Grant Awardee
Aug 2023 | 2023 ASEE Annual Conference & ExpositionDespite widespread acknowledgement of PLM technologies’ pivotal role in supporting modern industry, undergraduate STEM programs often struggle to include instruction on PLM topics due to the difficulty of covering the preponderance of discipline-specific concepts inherent in traditional curricula within the allocated credit hours. This paper discusses the establishment and operation of a new center at with directives to prepare collegiate students in utilizing PLM technologies through a variety of extracurricular activities and PLM resources. These include short-course lectures, guided software workshops, semester-length projects, support for research activities, and provision of PLM software in an open-access computer lab. To access the effectiveness of these educational efforts, the analysis of student surveys can help to tailor the activities to better meet learning needs. This model of supporting traditional curricula with extracurricular activities shows potential in preparing students for career roles driven by modern, digital processes.
@unpublished{morrisApplicationProductLifecycle2023,
title = {Application of {{Product Lifecycle Management}} in the {{University Classroom}} and {{Laboratory}}},
author = {Morris, John},
date = {2023-08-01},
eventtitle = {2023 {{ASEE Annual Conference}} \& {{Exposition}}},
venue = {Baltimore, MD},
}
Mentored Presentations
-
Development of Mechanisms Supporting Digital Twins in a Model-Based Engineering Ecosystem
William Ainsworth, Brady Bostic, Jake Czawkiel, Brady Davis, Abigail Evans, Liam Foley, Davis Graham, Peter Hoang, Adrian Koehler, William Peterson, Brent Rice, Jonathan Tran, Nicholas Welborn, Max Zyblewski
Apr 2025 | Clemson University 20th Annual Focus on Creative Inquiry Forum@unpublished{ainsworthDevelopmentMechanismsSupporting2025,
type = {Poster},
title = {Development of {{Mechanisms Supporting Digital Twins}} in a {{Model-Based Engineering Ecosystem}}},
author = {Ainsworth, William and Bostic, Brady and Czawkiel, Jake and Davis, Brady and Evans, Abigail and Foley, Liam and Graham, Davis and Hoang, Peter and Koehler, Adrian and Peterson, William and Rice, Brent and Tran, Jonathan and Welborn, Nicholas and Zyblewski, Max},
namea = {Wagner, John and Mocko, Gregory and Morris, John},
nameatype = {collaborator},
date = {2025-04},
eventtitle = {Clemson {{University}} 20th {{Annual Focus}} on {{Creative Inquiry Forum}}},
venue = {Clemson, SC},
}
-
Development of Digital Twin for Scaled Robotic Vehicle
Lia Anderson, Clarke Coco, Patrick O'Neill, Emilee Ransom, Comfort Samuel, Sydney Thompson, Sophia Zanotta
Apr 2024 | 19th Annual Focus on Creative Inquiry Forum
@unpublished{andersonDevelopmentDigitalTwin2024,
type = {Poster},
title = {Development of {{Digital Twin}} for {{Scaled Robotic Vehicle}}},
author = {Anderson, Lia and Coco, Clarke and O'Neill, Patrick and Ransom, Emilee and Samuel, Comfort and Thompson, Sydney and Zanotta, Sophia},
date = {2024-04-03},
url = {https://ci.clemson.edu/foci/posters/},
eventtitle = {19th {{Annual Focus}} on {{Creative Inquiry Forum}}},
venue = {Clemson, SC},
}
-
Exploring Digital Technologies - A Focus on PLM Concepts and Software with Application to Scale Track Vehicle
Lia Anderson, William Bishop, Brandon Ewanick, Vanessa Foy, Austin Frabotta, Alexander Minnich, Brent Rice, Sydney Thompson
Apr 2023 | 18th Annual Focus on Creative Inquiry Forum
@unpublished{andersonExploringDigitalTechnologies2023,
type = {Poster},
title = {Exploring {{Digital Technologies}} - {{A Focus}} on {{PLM Concepts}} and {{Software}} with {{Application}} to {{Scale Track Vehicle}}},
author = {Anderson, Lia and Bishop, William and Ewanick, Brandon and Foy, Vanessa and Frabotta, Austin and Minnich, Alexander and Rice, Brent and Thompson, Sydney},
date = {2023-04},
url = {https://ci.clemson.edu/foci/posters2023/},
eventtitle = {18th {{Annual Focus}} on {{Creative Inquiry Forum}}},
venue = {Clemson, SC},
}
-
PLM Processes and CAD/CAE Tools with Application to Vehicle Component Design
Clark Beuckman, Michael Calamari, Sam Gossett, Noah Wanthal, Brenden Schumm
Apr 2022 | 17th Annual Focus on Creative Inquiry Forum@unpublished{beuckmanPLMProcessesCAD2022,
type = {Poster},
title = {{{PLM Processes}} and {{CAD}}/{{CAE Tools}} with {{Application}} to {{Vehicle Component Design}}},
author = {Beuckman, Clark and Calamari, Michael and Gossett, Sam and Wanthal, Noah and Schumm, Brenden},
namea = {Morris, John and Mocko, Gregory and Wagner, John},
nameatype = {collaborator},
date = {2022-04},
eventtitle = {17th {{Annual Focus}} on {{Creative Inquiry Forum}}},
venue = {Clemson, SC},
}
Reports and Theses
-
Universal Systems Simulation via Constraint Hypergraphs with Applications to Digital Twins
John Morris
Dec 2025 | Clemson University
The characterization of systems encompasses a variety of modeling frameworks designed to capture specific behaviors and components of various system domains. Whatever the framework, the core elements of a system representation are the information of the system and a description of how that information is related. The relations in deterministic systems are functions, which, when composed to form executable processes, can be used to simulate system data. A declarative modeling framework is one that encodes mechanisms for preparing these simulations within the model structure, allowing an external agent to form the execution processes required for a given context. To date, no declarative modeling framework has been proposed that allows for these processes to be discovered for any system across any domain. In this dissertation, a new framework called a constraint hypergraph is proposed that provides universal, declarative modeling. System behavior is embedded in this framework as paths through the hypergraph. Simulating a system represented with a constraint hypergraph can be accomplished by an autonomous agent capable of discovering these paths. This, combined with the graphical nature of the framework, allows system information to be interrogated autonomously across domains, enabling multiphysics, multiscale modeling and simulation of complex systems. Applications of this framework are shown to model-based engineering platforms and digital twins. The former is given by showing how updatable digital threads can be traced throughout a data ecosystem, including across analysis software platforms such as CAD and FEA tools. Constraint hypergraphs are also shown to provide a robust foundation for creating digital twins, leading to twins that are usable, interoperable, maintainable, and verifiable. These applications are demonstrated using custom algorithms published in the open-source package ConstraintHg.
@thesis{morrisDissertation,
type = {phdthesis},
title = {Universal {{Systems Simulation}} via {{Constraint Hypergraphs}} with {{Applications}} to {{Digital Twins}}},
author = {Morris, John},
date = {2025-12-12},
series = {All {{Dissertations}}},
number = {4127},
institution = {Clemson University},
location = {Clemson, SC, USA},
url = {https://open.clemson.edu/all_dissertations/4127},
urldate = {2026-01-20},
}
-
2024-2025 Annual Report for the Product Lifecycle Management Center at Clemson University
John Morris, John Wagner
Sep 2025 | Product Lifecycle Management Center at Clemson University@report{PLMC2025AnnualReport,
title = {2024-2025 {{Annual Report}} for the {{Product Lifecycle Management Center}} at {{Clemson University}}},
author = {Morris, John and Wagner, John},
date = {2025-09-28},
pages = {31},
institution = {Product Lifecycle Management Center at Clemson University},
location = {Clemson, SC},
}
-
2023-2024 Annual Report for the Product Lifecycle Management Center at Clemson University
John Morris, John Wagner
Sep 2024 | Product Lifecycle Management Center at Clemson University@report{PLMC2024AnnualReport,
title = {2023-2024 {{Annual Report}} for the {{Product Lifecycle Management Center}} at {{Clemson University}}},
author = {Morris, John and Wagner, John},
date = {2024-09-03},
pages = {29},
institution = {Product Lifecycle Management Center at Clemson University},
location = {Clemson, SC},
}
-
2023 VIPR-GS Diversity, Inclusion, and Education Initiatives
John Morris, Serita Acker, Tonyia Stewart, John Wagner
Jun 2023 | VIPR-GS CenterThe research objectives of the VIPR-GS collaboration are built of increasing maturation in science and engineering research to adopt next-generation paradigms and toolsets. These developments are immediately driven by the community of scientists and engineers and supported by the contributions of GVSC into the VIPR-GS center. However, ensuring the availability of technical expertise requires continual investment into the diversity and education of each upcoming generation of researchers. Due to this, significant efforts have been made to expand the benefits of VIPR-GS research into promoting diversity, inclusion, and educational provisions. These initiatives provide pre-career individuals opportunities to develop into the advanced academic expertise required of sustained innovation.
@report{morris2023VIPRGSDiversity2023,
type = {Technical Status Report},
title = {2023 {{VIPR-GS Diversity}}, {{Inclusion}}, and {{Education Initiatives}}},
author = {Morris, John and Acker, Serita and Stewart, Tonyia and Wagner, John},
date = {2023-06-30},
institution = {VIPR-GS Center},
location = {Clemson, SC},
}
Tools
-
MicrogridHg
May 2025 | Clemson, Naval Postgraduate School
This model describes the behavior of a microgrid, formalized in a constraint hypergraph. Flexible for various configurations, the microgrid is universally simulatable, allowing a modeler to simulate any piece of the model by a single call. The default configuration of the microgrid consists of 12 actors of 5 different types: batteries (2), buildings (5), generators (2), photovoltaic arrays (1), all connected to each other and the greater utility grid along 2 busses. Different configurations are also possible, allowing for quick descriptions of microgrid behavior.
@software{morrisMicrogridHg2025,
title = {{{MicrogridHg}}},
author = {Morris, John},
namea = {Van Bossuyt, Douglas L.},
nameatype = {collaborator},
date = {2025-05-16},
doi = {10.5281/zenodo.15447062},
organization = {Clemson, Naval Postgraduate School},
version = {v1.0},
}
-
Dynamic Estimator of CAD Patterning Feature Execution Time
Aug 2023 | PLM Center at Clemson University
Siemens NX plugin for estimating the time necessary to complete a pattern feature.
@software{morrisDynamicEstimatorCAD2023a,
title = {Dynamic {{Estimator}} of {{CAD Patterning Feature Execution Time}}},
author = {Morris, John},
date = {2023-08-20},
location = {Clemson},
url = {https://github.com/Clemson-PLMC/PatternEstimatorTool},
organization = {PLM Center at Clemson University},
version = {1.0},
}
Press and Media
-
PLM Processes--Creative Inquiry
Kat Sahd
Apr 2025 | Decipher
@article{sahdPLMProcessesCreativeInquiry2025,
entrysubtype = {magazine},
title = {{{PLM Processes--Creative Inquiry}}},
author = {Sahd, Kat},
date = {2025-04},
journaltitle = {Decipher},
volume = {12},
url = {https://ci.clemson.edu/blogs/blog/2025/04/plm-processes/},
urldate = {2025-07-15},
langid = {american},
}
-
Clemson's Project WISE Summer Camp Gets 7th and 8th-Graders Excited about STEM Careers
Ken Scar
Jun 2022 | Clemson News
More than three dozen rising 7th and 8th-graders from underserved communities around South Carolina were given a unique college experience in a summer camp designed to change their lives.
@online{scarClemsonsProjectWISE2022,
title = {Clemson's {{Project WISE}} Summer Camp Gets 7th and 8th-Graders Excited about {{STEM}} Careers},
author = {Scar, Ken},
date = {2022-06-29T15:14:36+00:00},
url = {https://news.clemson.edu/clemsons-project-wise-summer-camp-gets-7th-and-8th-graders-excited-about-stem-careers/},
urldate = {2025-07-28},
langid = {american},
organization = {Clemson News},
}
Other
-
A PLM-Focused, Multi-Disciplinary Creative Inquiry Course at Clemson University
Mara Kinsey, John Morris, John Wagner
Jan 2022 | Siemens Aspire
@article{kinseyPLMFocusedMultiDisciplinaryCreative2022,
entrysubtype = {newspaper},
title = {A {{PLM-Focused}}, {{Multi-Disciplinary Creative Inquiry Course}} at {{Clemson University}}},
author = {Kinsey, Mara and Morris, John and Wagner, John},
date = {2022},
journaltitle = {Siemens Aspire},
edition = {April Edition},
url = {https://view.highspot.com/viewer/6220fc66c2d0aa20acf42c3a},
urldate = {2025-07-15},
langid = {english},
}