Reduced rank extrapolation (RRE) is an acceleration method typically used to accelerate the iterative solution of nonlinear systems of equations using a fixed-point process. In this context, the iterates are vectors generated from a fixed-point mapping function. However, when considering the iterative solution of large-scale matrix equations, the iterates are low-rank matrices generated from a fixed-point process for which, generally, the mapping function changes in each iteration. To enable acceleration of the iterative solution for these problems, we propose two novel generalizations of RRE. First, we show how to effectively compute RRE for sequences of low-rank matrices. Second, we derive a formulation of RRE that is suitable for fixed-point processes for which the mapping function changes each iteration. We demonstrate the potential of the methods on several numerical examples involving the iterative solution of large-scale algebraic Lyapunov and Riccati matrix equations.
Because radio communication is the main source of power consumption in wireless sensor nodes, duty cycling is commonly used to extend battery life. However, duty-cycled communication leads to high latency, making on-demand and event-based communication impractical. Wake-up receivers address this issue by reducing energy consumption during reception. Since most wake-up receivers operate in always-on mode, they enable low-latency and event-based communication. Given the wide variety of design approaches, a clear overview is needed. Many existing solutions are incompatible with real-world deployment, require custom fabrication, or lack repeatability. Therefore, there is a strong need to focus on prototypes based on commercial off-the-shelf components. These offer practical advantages in terms of cost, availability, and ease of integration. This article surveys the literature over the period of 2002-2024. We analyzed over 120 articles dealing with this topic. We examined, characterized, and classified 132 wake-up receiver prototypes. We identified the main building blocks of wake-up receivers and analyzed the components and circuits used. Additionally, we highlighted the strengths and limitations of current research and provided an outlook on future research directions.
Structural Supercapacitors (SSCs) are multifunctional carbon fiber-reinforced composites that combine mechanical load-bearing capacity with energy storage functionality. However, the interplay between mechanical deformation and electrostatic charge storage remains insufficiently understood. This study presents a quasi-static finite element sequential interaction modeling framework to investigate electro-mechanical phenomena at the microscale in SSCs. By explicitly excluding the Electric Double Layer (EDL) physics, the model focuses on how compressive stress influences the bulk electrostatic field distribution within a representative fiber-electrolyte architecture. This approach serves as a geometric benchmark to isolate first-order effects. Results reveal a deformation-induced evolution of electric field distribution, particularly near fiber-separator line interfaces, which in turn affects the local charge storage behavior. Although the overall capacitance is largely retained under compressive deformation, minor variations arise due to small changes in fiber proximity and the mechanism termed Geometric Electrostatic Screening. Parametric studies demonstrate that fiber volume fraction and spatial arrangement play a significant role in the capacitance, with optimized geometries enabling up to 20
We introduce AuxFlow, a novel, temporally-aware pipeline for homography estimation and field registration in challenging football broadcast footage. To overcome the temporal instability and high performance variance of existing per-frame keypoint methods, our AuxFlow approach combines a robust frame-wise keypoint model with a temporal propagation strategy. The system automatically identifies high-confidence ”anchor” frames where it estimates the homography solely based on the keypoint model, before sampling auxiliary points, which are re-identified in neighbouring frames using optical flow to establish dense, coherent correspondences across the sequence. This significantly enhances the stability and accuracy of the estimated homographies. Our evaluation on the SoccerNet GSR dataset shows consistent, measurable improvements in robustness and smoothness over existing State-of-the-Art, enabling highly reliable player localization invaluable for downstream applications.
Construction processes intensively contributes to greenhouse gas emissions worldwide. The resulting climate change affects historic buildings and complicates built heritage preservation. However, there are several actions under way, such as the European Green Deal, to reduce CO2 emissions in construction. Revaluation of existing structures under application of recycled materials and by re-use of available building elements may save resources and thus reduces emission of CO2 in construction industry. This contributes to a more environmentally friendly construction process. Furthermore, re-using of existing building materials or elements may preserve the historical appearance of structures, in the interest of future generations. For production and usage of new building materials and elements, a plethora of legislation and codes needs to be considered. The same applies to re-use of existing building materials and elements which increases the danger for construction defects and thus expensive claims. Thus, beside the advantages, re-using of building materials and elements bears risks to all stakeholders in a construction project. In the interest of avoiding conflicts between the construction contract parties, a legal risk analysis is necessary to support them in decision about the re-use of existing building materials and elements. The authors examined current international, European and German law, codes, and policy dealing with re-use of building materials and elements. Furthermore, they reviewed existing literature about that topic and analyzed relevant court cases of the last twenty years. The conclusion is, that there is a need for a detailed contract specification which kind of existing building elements and materials can be re-used and who takes the responsibility for known or unknown defects under the aspect of liability. The paper provides suggestions under which legal aspects a re-use of building elements may be recommendable and which requirements need to be met.
