Peter Gorm Larsen

Aarhus University | AU · Department of Engineering

To enable the reuse of Digital Twins, in the form of simulation units or other forms of behavioral models, of single physical components, one must be able to connect and couple them. Current platform and architectures consider mostly monolithic digital twins and offer little support for coupling and checking the consistency of the coupling. The cou...

The robots of tomorrow should be endowed with the ability to adapt to drastic and unpredicted changes in their environment and interactions with humans. Such adaptations, however, cannot be boundless: the robot must stay trustworthy. So, the adaptations should not be just a recovery into a degraded functionality. Instead, they must be true adaptati...

This paper proposes a novel anomaly detection system to identify combustion process irregularities in real-time within individual cylinders of marine engines. The system monitors the instantaneous speed of the crankshaft to detect deviations that might indicate abnormal power output from specific cylinders. This information is then communicated to...

Establishing digital twins is a non-trivial endeavour especially when users face significant challenges in creating them from scratch. Ready availability of re-usable models, data, functions, and tool assets, can help with creation and use of digital twins. A number of frameworks/platforms exist to facilitate creation and use of digital twins. In t...

Pioneering work in model-oriented specification showed that properties of software could be confirmed or refuted from the early stages of development and be verifiably preserved through design to implementation. As verification technology has evolved, research and innovation have had to balance the insight generated by hand-crafted proof with the b...

At the heart of a digital twin is one or more models of the real-world system that it aims to describe. There are many facets to real-world systems, and many types of model available to describe them, each with different strengths. We provide an introduction to a range of model types. These include physics-based models founded on first principles l...

Digital Twin (DT)-enabled systems depend on communications and networking, and so face a range of threats to their security. This chapter reviews approaches to managing or mitigating these threats. Approaches that are already well established in the software industry, techniques based on formal methods and finally, control theory approaches using f...

We report a virtual “roundtable” discussion on Digital Twins (DTs) involving experts from four engineering sectors covering consumer electronics, the built environment, aerospace and infrastructure. Topics covered include the vision, benefits and risks for DT technology in each sector, approaches to DT engineering and the role of dependability. The...

Digital Twins (DTs) integrate models with data gathered from Physical Twin (PT) counterparts, adding value through enablers and services that allow informed decision-making about the reconfiguration of the PT, either autonomously, or by human stakeholders.We consider the potential of DTs for improving the capabilities and performance of autonomous...

This chapter introduces concepts that form the foundations for systematically considering the engineering of digital twins for cyber-physical systems. We introduce an example based on an incubator for growing tempeh, which serves as a running study for the remainder of this book. Based on this example,we discuss basic system concepts and core featu...

Building a Digital Twin (DT) can be a challenge, in part because of the variety of assets, models, data and services that must be marshalled to satisfy the specific needs of stakeholders. In this chapter, we consider the possibility of a generic platform that allows DTs to be built from reusable components and offered as a service to users. We prop...

This chapter explores Digital Twin (DT) services that help to support decision-making, and the instigation of change in the DT’s Physical Twin. We consider “what-if” analysis – the examination in parallel of multiple alternative scenarios – and related topics including design space exploration and fault injection. The potential of the DT in fault d...

This chapter describes the potential of visualisation as a service offered by the digital twin of a cyber-physical system. Much of the value of visualisation technology comes from the ability to present stakeholders with a representation of the state and dynamics of the scyber-physical system, augmented with the results of simulation, analysis and...

Although digital twins have been around for decades, there are many areas of research that need to be pursued in order to enable trustworthy predictions. The existing challenges and the future directions to take can be organised in many different ways. In this chapter, the foundational issues that we still think require clarification comes first. T...

In this chapter we introduce the concept of Digital Twin (DTs) for cyberphysical systems. We describe aspects of the technical engineering of DT-enabled systems, including their model-centric character, the need to maintain fidelity to the physical world, and the need to add value to the system being twinned. We examine the conceptual structure of...

A Digital Twin (DT) has great potential as a tool for monitoring, detecting and reporting anomalies. Such advance warning allows stakeholders to sidestep failures, or to be better prepared to recover from them. This chapter introduces modelbased and data-driven approaches to monitoring in DTs. Model-based monitoring uses definitions of properties (...

Digital Twins (DTs) can be constructed for many different applications, leading to substantial differences between different case studies. To be able to learn from the challenges and lessons learned by other DT practitioners, it is important that experience reports be consistent to facilitate comparisons. In this paper, we merge three reference des...

Testing of large wind turbine components plays a central role in delivering reliable yet cost-effective technology. However, these experiments are often lengthy and costly. Fatigue testing of a wind turbine blade might take up to 12-14 months, whereas highly accelerated lifetime testing of a nacelle demands 6-8 months. The exchange of simulation mo...

Thanks to great advances such as in connectivity (including IoT, Big Data), pattern recognition and decision making (AI) and integration technologies (CPS), with computing as a backbone, there is a convergence of technology domains and the real world towards the Next Computing Paradigm (NCP). The integration concerns typical in the realm of CPS, in...

Digital twin (DT) technology has been a topic with academic and industrial coverage in recent years. DTs are intended to be a virtual high‐fidelity representation of a physical counterpart. Its complex nature requires several components to create and run a DT, and that is why many DT frameworks have been proposed in the literature. There are also m...

This paper describes challenges in the composition of cyber-physical systems enabled by digital twins. Digital twins link virtual models with the real systems that they represent, adding value to these models throughout the system’s life. As we come to rely on federations of systems, there is good reason to be interested in the composition of both...

Design for Circular Economy (DfCE) is becoming a principal focus in industries to replace the traditional linear system with a closed-loop approach. Holistically supporting DfCE requires developing decision-making tools that are able to model the behaviour of a product or system over its entire lifecycle. Thus, the ability to link potentially diffe...

This report describes the state of the art in verifiable computation. The problem being solved is the following: The Verifiable Computation Problem (Verifiable Computing Problem) Suppose we have two computing agents. The first agent is the verifier, and the second agent is the prover. The verifier wants the prover to perform a computation. The veri...

The model-based engineering of dependable robotic systems brings challenges that include the need to work effectively with a range of models, owners and operators, and addressing the extent to which the systems evolve over time. This paper explores the linking of co-simulation, which allows for the exploration of models composed of multiple diverse...

Battery management systems (BMSs) are critical to ensure the efficiency and safety of high-power battery energy storage systems (BESSs) in vehicular and stationary applications. Recently, the proliferation of battery big data and cloud computing advancements has led to the development of a new generation of BMSs, named Cloud BMS (CBMS), aiming to i...

There has been a rapid rise of interest in the potential of digital twins to transform a vast range of Cyber-Physical System (CPS) applications, from national infrastructure to surgical robots. But what frameworks, methods and tools are needed to create and maintain digital twins on which we can depend?

Transportation electrification has been fueled by recent advancements in the technology and manufacturing of battery systems, but the industry yet is facing serious challenges that could be addressed using cutting-edge digital technologies. One such novel technology is based on the digital twining of battery systems. Digital twins (DTs) of batterie...

Digital Twins (DTs) are built using modelling and simulation techniques in complex domains such as cyber-physical systems. However, further formal investigation is required for how a DT and the services it provides relate to the qualities of the models used by a service. Specifically, this article examines when a DT service can be said to have the...

Establishing digital twins is a non-trivial endeavour especially when users face significant challenges in creating them from scratch. Ready availability of reusable models, data and tool assets, can help with creation and use of digital twins. A number of digital twin frameworks exist to facilitate creation and use of digital twins. In this paper...

A digital twin (DT) monitors states of the physical twin (PT) counterpart and provides a number of benefits such as advanced visualizations, fault detection capabilities, and reduced maintenance cost. It is the ability to be able to detect the states inside the DT that enable such benefits. In order to estimate the desired states of a PT, we propos...

The VDM-PlantUML Plugin enables translations between the text based UML tool PlantUML and VDM++ and has been released as a part of the VDM VSCode extension. This enhances already extensive feature-set of VDM VSCode with support for UML. The link between VDM and UML is thoroughly described with a set of translation rules that serve as the base of th...

For recursive functions general principles of induction needs to be applied. Instead of verifying them directly using the Vienna Development Method Specification Language (VDM-SL), we suggest a translation to Isabelle/HOL. In this paper, the challenges of such a translation for recursive functions are presented. This is an extension of an existing...

The game of chess is well-known and widely played all over the world. However, the rules for playing it are rather complex since there are different types of pieces and the ways they are allowed to move depend upon the type of the piece. In this paper we discuss alternative paradigms that can be used for modelling the rule of the chess game using V...

Digital twins (DTs) represent a key technology in the development, real-time monitoring and optimisation of cyber–physical systems (CPSs). Such potential emerges as a result of the real-time coupling between DTs and their physical counterparts, where it is possible to make use of operational data as it is being generated in order to aid decision-ma...

The development of future large-scale safety-critical systems, also known as cyber-physical systems (CPS), involves many technology and influencer communities. Novel approaches and tools will be required to tackle the multi-dimensional challenges between these communities to benefit CPS, especially their adaptability to new technologies. ere are ma...

Dynamical systems see widespread use in natural sciences like physics, biology, chemistry, as well as engineering disciplines such as circuit analysis, computational fluid dynamics, and control. For simple systems, the differential equations governing the dynamics can be derived by applying fundamental physical laws. However, for more complex syste...

Digital Twins (DTs) are a promising technology for integrating device monitoring and data consumption to improve performance. This technology has seen utilisation in various industries that use cyber-physical systems. An unexpected area is medical devices. In this paper, we explore DTs use for an organ preservation device, which, helps improve tran...

Technologicaladvances in sensing, communications, and data analytics make it possible to construct virtual replicas of Cyber-Physical Systems (CPSs). Such replicas are known as digital twins. They can either make decisions on system updates during operation or provide input to decision-makers for system evolution. This short paper introduces the IS...

Advanced digital technology is finding its way into industrial production and control systems. This led to development of further concepts such as digital shadow and digital twin. In the former an accurate model of the cyber-physical system (CPS) is used to monitor it virtually, while the latter provides a possibility to adapt the CPS’s behavior. T...

Current trends of digitalization are becoming significantly prevalent within the field of industrial control systems. While in recent history a typical industrial control system would have been isolated with rudimentary ways of extracting data, nowadays it is becoming expected that the control system could not only provide large amounts of data ove...

The synchronization between a Digital Shadow (DS) and a Cyber-Physical System (CPS) is paramount to enable anomaly detection, predictive maintenance, what-if analysis, etc. Such synchronization means that a simulation reflects, as closely as possible, the states of the CPS. The simulation however, requires the complete initial state of the system t...

Digital twin technology is an essential approach to managing the lifecycle of industrial products. Among the many approaches used to manage digital twins, co-simulation has proven to be a reliable one. There have been multiple attempts to create collaborative and sustainable platforms for management of digital twins. This paper compares two such pl...

Digital Twins (DTs) are real-time digital models that allow for self-diagnosis, self-optimization and self-configuration without the need for human input or intervention. While DTs are a central aspect of the ongoing fourth industrial revolution (I4.0), this leap forward may be reserved for the established, large-cap companies since the adoption of...

In today’s world, critical infrastructure is often controlled by computing systems. This introduces new risks for cyber attacks, which can compromise the security and disrupt the functionality of these systems. It is therefore necessary to build such systems with strong guarantees of resiliency against cyber attacks. One way to achieve this level o...

The amount of robots in industry is increasing, pushing the need for easier configuration and integration of robots. The cost of robot integration is often larger than the cost of the robots themselves. With the increasing complexity of robotic systems and the tasks they perform, the future of reducing the expenses of robot system integration is si...

We introduce AURT, an open-source software for modeling and calibration of robot manipulator dynamics. AURT includes rigid-body dynamics and a selection of joint dynamics models. The separation of the robot dynamics into rigid-body dynamics and joint dynamics allows for fast recalibration of the robot dynamics using different joint dynamics models....

Throughout their useful life, plastic injection moulds operate in rapidly varying cyclic environments, and are prone to continual degradation. Quantifying the remaining useful life of moulds is a necessary step for minimizing unplanned downtime and part scrap, as well as scheduling preventive mould maintenance tasks such as cleaning and refurbishme...

Dynamical systems see widespread use in natural sciences like physics, biology, chemistry, as well as engineering disciplines such as circuit analysis, computational fluid dynamics, and control. For simple systems, the differential equations governing the dynamics can be derived by applying fundamental physical laws. However, for more complex syste...

Hybrid testing is an experimental technique extensively utilized in earthquake engineering to study the seismic response of structures. It requires coupling physical and numerical models in a closed feedback loop. Although this methodology is mature, a commonly accepted standard for orchestrating simulations and experiments is still missing. As a r...

In today's world, critical infrastructure is often controlled by computing systems. This introduces new risks for cyber attacks, which can compromise the security and disrupt the functionality of these systems. It is therefore necessary to build such systems with strong guarantees of resiliency against cyber attacks. One way to achieve this level o...

The Language Server Protocol (LSP) changed the field of Integrated Development Environments(IDEs), as it decouples core (programming) language features functionality from editor smarts, thus lowering the effort required to extend an IDE to support a language. The concept is a success and has been adopted by several programming languages and beyond....

A digital twin for a Cyber-Physical System includes a simulation model that predicts how a physical system should behave. We show how to quantify and characterise violation events for a given safety property for the physical system. The analysis uses the digital twin to inform a runtime monitor that checks whether the noise and violations observed...

Advances in sensing, communications and data analytics have made it possible to construct virtual replicas of Cyber-Physical Systems (CPSs). Such replicas, known as digital twins, can in principle inform decision making during operation and evolution of the systems they model. This short paper introduces the ISoLA 2020/21 series of papers on the te...

A digital twin for a Cyber-Physical System includes a simulation model that predicts how a physical system should behave. We show how to quantify and characterise violation events for a given safety property for the physical system. The analysis uses the digital twin to inform a runtime monitor that checks whether the noise and violations observed...

Civil engineering has only recently started the digitalisation journey by standardising around Building Information Models (BIMs). In the process of construction a dimension of time is added in what is called 4D BIM and this can serve as the basis for a digital twin. It is predicted that such a digital twin can enhance the overall overview of statu...

Advances in sensing, communications and data analytics have made it possible to construct virtual replicas of Cyber-Physical Systems (CPSs). Such replicas, known as digital twins, can in principle inform decision making during operation and evolution of the systems they model. This short paper introduces the ISoLA 2020/21 series of papers on the te...

In this paper, we provide an extended exposition of a novel cloud-enabled and open collaboration platform, which intends to lower the barriers faced by businesses, particularly small and medium-sized enterprises, aiming to start up in Model-Based Design. In the development of Cyber-Physical Systems the usual start up challenges are exacerbated by t...

The Language Server Protocol (LSP) changed the field of Integrated Development Environments (IDEs), as it decouples core (programming) language features functionality from editor smarts, thus lowering the effort required to extend an IDE to support a language. The concept is a success and has been adopted by several programming languages and beyond...