275003 research outputs found
Sort by
Perception-oriented Video Coding based on Image Analysis and Completion: A Review
No full textPerception-oriented video coding based on image analysis and completion (IAC) has received increasing attention over recent years. Several approaches have been proposed that follow diverging strategies: from full compatibility to hybrid block transform coding to alternative codec designs. In this paper, we review the most significant issues in IAC coding and their relevance for future codec designs. The most promising pathways will be analyzed along with limitations and open issues. The challenges in IACbased video coding will be summarized using methods developed by the authors and others for block-based and region-based IAC coding
Method—Impedance Modeling of Lithium Plating During Fast Charging of Lithium-Ion Cells to Derive Monitoring Strategies
No full textLithium-ion batteries play a key role in electrifying the transport sector. However, short charging times are crucial for consumers to accept battery electric vehicles (BEV). Fast charging makes the battery vulnerable to lithium plating, which leads to rapid cell aging and can cause a thermal runaway. Hence, a strict criterion in the optimization and adaption of fast charging processes is avoiding lithium plating. Simple plating detection methods are needed to optimize and adjust charging strategies precisely. In this study, a stepwise simplification of a lithium plating detection method from a three-electrode setup to a full cell setup is deduced. An equivalent circuit model is used to explain a sudden drop in cell impedance during fast charging, which is a characteristic feature of the lithium plating onset. This feature also appears in the full cell impedance and can be observed by measuring the impedance at one single frequency. Suitable frequencies lie in a low frequency range, where the measurements can be performed with simple devices that may be integrated into a BEV’s battery management system (BMS). Measuring the lithium plating behavior during operation over its lifespan allows continuous adjusting of the charging strategy, which enables faster charging and improves safety.1711
A Port-Hamiltonian Modeling Approach for Integrated Hydrogen Systems
No full text555560Hydrogen's growing role in the transition towards climate-neutral energy systems necessitates structured modeling frameworks. Existing gas network models, largely developed for natural gas, fail to capture hydrogen systems distinct properties, particularly the coupling of hydrogen pipes with electrolyzers, fuel cells, and electrically driven compressors. In this work, we present a unified systematic port-Hamiltonian (pH) framework for modeling hydrogen systems, which inherently provides a passive input-output map of the overall interconnected system and, thus, a promising foundation for structured analysis, control and optimization of this type of newly emerging energy systems
Direct Contact Prelithiation of Multi-Layered Lithium-Ion Battery Pouch Cells Using a Scalable Prelithiation Process
No full textPrelithiation is known to enhance the performance of lithium-ion batteries and is becoming increasingly popular. To date, different approaches and concepts for prelithiation processes have only been implemented on a laboratory scale, which is due to the complex upscaling of the process approaches. Moreover, investigations of prelithiation approaches are mostly limited to small-format laboratory cells, and concepts for implementation on an industrial scale are scarce. The present study introduces a scalable, roll-to-roll capable process for direct contact prelithiation of anodes for large-format and multi-layered pouch cells. The process is based on calendering for applying lithium foils to anodes. The feasibility of scaling the approach from single-layer to multi-layer pouch cells was further investigated. The prelithiated cells with silicon-graphite composite anodes showed an improved first-cycle coulombic efficiency of up to 8% and increased coulombic efficiencies during cyclization compared to non-prelithiated cells. By improving capacity retention, cycle life could be increased by up to 170% compared to non-prelithiated cells. Post-mortem analyses conducted after 4000 cycles show that the direct contact prelithiation method used does not cause profound lithium plating. Summarizing, the employed direct contact prelithiation process is suitable for a scalable, industry-capable prelithiation of lithium-ion batteries.1711
A Literature Review: The Impact of Digital Transformation on Financial Performance
No full text331338In recent years, digital transformation (DT) has emerged as a significant driver of organizational change, promising to revolutionize business processes, enhance operational efficiency, and ultimately improve business success. This literature review examines the empirical evidence surrounding the impact of DT on financial performance (FP) across various industries and organizational contexts. The review synthesizes findings from empirical research to provide insights into the mechanisms through which DT influences key performance metrics such as profitability, revenue growth and return on investment (ROI). Through a comprehensive analysis of existing literature, this review aims to contribute to a deeper understanding of the complex relationship between DT and FP and to provide valuable implications for both scholars and practitioners seeking to navigate the digital landscape effectively
Multisegmental gastrointestinal dysmotilities: a surgical scenario for future implementation of theranostic devices
No full textAim: Multisegmental gastrointestinal (GI) dysmotilities, such as chronic intestinal pseudo-obstruction, may lead to life-threatening events. The interdisciplinary INTAKT project is developing wirelessly communicating GI devices for intelligent sensor technology and electrostimulation-based motility modulation. However, a concrete vision of clinical implementation has not been previously described. Methods: An interdisciplinary team of surgeons, gastroenterologists, biologists, engineers, veterinarians and product designers developed a clinical scenario based on pre-clinical experiments, contextual analysis and usage scenarios. Results: The surgical experiences of our previous studies with conventional open, laparoscopic and robotic setups were analyzed. Patient selection, a surgical strategy and perioperative management are described in detail. Conclusion: Further technological solutions may enable first-in-human trials according to our protocol.4
The Interplay of Humans, Technology, and Organizations in Realizing AI's Productivity Promise
No full text357362The integration of artificial intelligence (AI) in the workplace is at a nascent stage, presenting both substantial opportunities and challenges for productivity growth. We argue that AI's potential will only be truly realized through strategic investments in human skills and comprehensive organizational redesign. Drawing on interdisciplinary insights, we highlight the critical role of AI-human collaboration, continuous workforce skill development, and adaptive organizational practices. We conclude with recommendations to create a human-centered environment conducive to AI-driven productivity gains through its assistance, augmentation, and automation capabilities.21
Multi-Task Deep Learning Approach for Contactless Simultaneous Heart Rate and Oxygen Saturation Estimation
No full textPulse oximeters are commonly used for health monitoring to measure heart rate (HR) and peripheral oxygen saturation (SpO2). For better hygiene and comfort, camera based non-contact vital signs monitoring has become increasingly popular. In this work, we present and validate for the first time a novel approach using a multi-task neural network to simultaneously estimate the absolute values of HR and SpO2 from multispectral video. The approach begins by preprocessing the multispectral video across the spatial, temporal, and frequency domains. The proposed network structure incorporates partially shared feature extractors and task-specific branches, along with a feature map channel attention mechanism and task weight balancing mechanism. This design enhances the extraction of shared shallow features for HR and SpO2, leveraging their interrelationships, and then focuses on the more relevant and informative features for each task. The performance is validated through short measurements of 23 healthy participants using a 3D multispectral multimodal cameras system in a breath-holding study approved by the Ethics Committee of the Faculty of Medicine, University of Duisburg-Essen (approval no. 21-10312-BO). In the leave-oneparticipant-out validation scenario, compared with parallel commercial pulse oximeter recordings, the mean absolute error of HR and SpO2 measurements are 2.97 beats per minute and 2.34 % respectively. And the Pearson correlation coefficient of HR and SpO2 measurements are 0.54 and 0.68 respectively. The result demonstrates good precision and notable agreement with the commercial pulse oximeter, indicating the potential of this approach to contribute a hygienic and comfortable alternative for simultaneous HR and SpO2 measurement
Experimental and numerical analysis of the adapted high-pressure cutting fluid supply for turning AISI 1045 steel
No full text432437In continuous cutting, the use of high-pressure cutting fluid supply improves fluid penetration at the tool/workpiece interface, improving heat dissipation and allowing higher cutting speeds for better machining efficiency. While prior research has mostly focused on the role of cutting fluid pressure, the influence of nozzle design on machining outcomes has not been thoroughly examined. This study explores the impact of various nozzle opening shapes and pressures on tool wear and workpiece surface roughness, utilizing additively manufactured nozzles. Findings indicate that chip morphology under the investigated cutting conditions is primarily influenced by cutting fluid pressure and is minimally affected by nozzle opening shape. In addition, the design of the flank face nozzle is crucial for optimizing surface roughness and extending tool life. The simulation results indicate that the difference in various flank face nozzles is due to changes in the flow velocity within the cutting zone.13
Improving the Backprojection Algorithm with Ray Tracing
No full text244247In this paper, we present a new method to improve image reconstruction by enhancing the Backprojection algorithm through the inclusion of ray tracing in the phase compensation. We place particular emphasis on the rotational setting. To this end, we introduce a calibration method to compensate the frequency response of the radar and calculate the center of rotation. Verification by experimental results shows a visible reduction of artifacts and improved localisation of object defects