Volume 73, Issue 2

Uncertainty is an inherent property of any complex system, especially those that incorporate physical parts or operate in real environments. In this paper, we focus on the Digital Twins of adaptive systems, which are particularly complex to design, verify, and optimize. One of the problems of having two systems (the physical one and its digital replica) is that their behavior may not always be consistent. In addition, both twins are normally subject to different types of uncertainties, which complicates their comparison. In this paper we propose the explicit representation and treatment of the uncertainty of both twins, and show how this enables a more accurate comparison of their behaviors. Furthermore, this allows us to reduce the overall system uncertainty and improve its behavior by properly averaging the individual uncertainties of the two twins. An exemplary incubator system is used to illustrate and validate our proposal.

Industry 4.0 emphasizes the flexibility of production systems, requiring dynamic adaptation to varied product requirements. This paper presents a framework for managing production systems by integrating application and communication systems. Central to it is the use of Asset Administration Shell (AAS) to create Digital Twins of assets, enabling continuous adaptation and optimization of production processes through effective resource management. The paper discusses a use case involving negotiation between communication and application systems, proposing a model-based solution leveraging AAS. It details the implementation of the proposed model with AAS components, providing an analysis of the use case and an automation solution. Validation results show how the AAS can improve the performance and dependability of wireless communication systems.

The NAMUR automation pyramid is the current state of the art in the process control industry, it is a monolithic structure with a bidirectional flow of information (top-down/bottom-up). Introducing new technologies into this structure would imply modifying or replacing the existing infrastructure. NAMUR NE 175 opens up this closed structure with a new NAMUR Open Architecture (NOA) to provide read-only access to external interfaces without changing the existing structure, safely, securely and reliably. In continuation of NE 175, NE 178 presents a verification of request concept to allow external Monitoring and Optimization applications to have write access to the devices. This paper attempts to model the actors involved in this concept and their interactions using the Pro-Active AAS introduces an interaction protocol and demonstrates the concept using a single water tank case study.

Current state-of-the-art evaluation methods for 6D pose estimation have several significant drawbacks. Existing error metrics can produce near-zero errors for poor pose estimations and are heavily dependent on the object point cloud used, resulting in vastly different outcomes for different objects. Furthermore, false detections are not considered at all. Evaluating pose estimators is crucial as it directly impacts the reliability and effectiveness of applications in robotics, augmented reality, and object manipulation tasks. Accurate evaluation ensures that pose estimators can be trusted to perform well in real-world scenarios, leading to better system performance and user satisfaction. In this paper, we conduct experiments to provide insights into how these metrics behave under isolated errors. We also introduce a novel evaluation approach with a metric independent of point clouds, making it applicable to a broader range of use cases than current metrics.

This publication examines the coordinated operation of pumped hydro energy storage and battery energy storage systems to improve profitability. While pumped hydro energy storages offer high storage capacity but have slower response times, battery energy storage systems have lower capacity but faster response times. A hybrid system combining both can thus harness synergies. A mixed-integer linear programming model was developed to depict the coordinated use of both systems in the German market. The proposed approach is also applicable to other regional markets where energy and balancing services are traded in a similar manner. In this model, the pumped hydro energy storage operates in the spot market and provides automatic Frequency Restoration Reserve, while the battery energy storage systems supplies Frequency Containment Reserve. The model takes into account the costs caused by degradation effects in both storage types. The results show a 10.05 % increase in revenue through coordination compared to the independent operation of both storage systems. This added value can be achieved through more efficient use of the power capacity, particularly that of the battery energy storage systems, in coordinated operation.

The Asset Administration Shell (AAS) is a standard for Digital Twins, a key element of Industry 4.0. In order to realize interoperability as its central prerequisite, manufacturers must implement the formal AAS metamodel specification correctly down to the last detail. To ensure this, conformance testing procedures should be defined and carried out as appropriate quality measures. This article presents comprehensive approaches to carry out formalized metamodel conformance tests for the AAS and its software components by describing the AAS Test Engines . First, the AAS software ecosystem is analyzed providing a systematic categorization of existing AAS software components. Based on these findings, basic building blocks and test setups needed for AAS conformance testing are identified. Then, implementation of these building blocks in the AAS Test Engines is described. Finally, usage, findings and limits of the presented methods based on a real-world case study from the AAS community are illustrated.