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arXiv 2023年

作者： Song, Rui Xu, Runsheng Festag, Andreas Ma, Jiaqi Knoll, Alois Fraunhofer Institute for Transportation and Infrastructure Systems IVI Ingolstadt85051 Germany Technical University of Munich Garching85748 Germany The Department of Civil and Environmental Engineering University of California Los AngelesCA90024 United States Ingolstadt85049 Germany

Bird’s eye view (BEV) perception is becoming increasingly important in the field of autonomous driving. It uses multi-view camera data to learn a transformer model that directly projects the perception of the road environment onto the BEV perspective. However, training a transformer model often requires a large amount of data, and as camera data for road traffic are often private, they are typically not shared. Federated learning offers a solution that enables clients to collaborate and train models without exchanging data but model parameters. In this paper, we introduce FedBEVT, a federated transformer learning approach for BEV perception. In order to address two common data heterogeneity issues in FedBEVT: (i) diverse sensor poses, and (ii) varying sensor numbers in perception systems, we propose two approaches – Federated Learning with Camera-Attentive Personalization (FedCaP) and Adaptive Multi-Camera Masking (AMCM), respectively. To evaluate our method in real-world settings, we create a dataset consisting of four typical federated use cases. Our findings suggest that FedBEVT outperforms the baseline approaches in all four use cases, demonstrating the potential of our approach for improving BEV perception in autonomous driving. © 2023, CC BY.

关键词： Birds

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Scalable Quantum Memory Nodes Using Nuclear Spins in Silicon Carbide

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Physical Review Applied 2023年第3期19卷 034026-034026页

作者： Shravan Kumar Parthasarathy Birgit Kallinger Florian Kaiser Patrick Berwian Durga B.R. Dasari Jochen Friedrich Roland Nagy Fraunhofer Institute for Integrated Systems and Device Technology (IISB) Germany Group of Applied Quantum Technologies (AQuT.) Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) Germany 3rd Institute of Physics and Stuttgart Research Center of Photonic Engineering (SCoPE) University of Stuttgart Stuttgart 70569 Germany Center for Integrated Quantum Science and Technology (IQST) Germany

A distributed quantum network would require quantum nodes capable of performing arbitrary quantum information protocols with high fidelity. So far the challenge has been in realizing such quantum nodes with features for scalable quantum computing. We show here that using the solid-state spins in 4H silicon carbide (4H SiC) such a goal could be realized, wherein a controlled generation of highly coherent qubit registers using nuclear spins is possible. Using a controlled isotope concentration and coherent control we perform here atomistic modeling of the central spin system formed by the electron spin of a silicon-vacancy color center (VSi− center) and the noninteracting nuclear spins. From this we lay out conditions for realizing a scalable nuclear-spin (13C or 29Si) register, wherein independent control of the qubits alongside their mutual controlled operations using the central electron spin associated to the VSi− center in 4H SiC are achieved. Further, the decoherence and entanglement analysis provided here could be used to evaluate the quantum volume of these nodes. Our results mark a clear route towards realizing scalable quantum memory nodes for applications in distributed quantum computing networks and further for quantum information protocols.

关键词： Color centers Quantum control Quantum information architectures & platforms Quantum information with solid state qubits Quantum memories Quantum networks Silicon vacancies Semiconductor compounds

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A Holonic Control System Approach for Line-less Mobile Assembly System Operations

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Procedia CIRP 2022年 107卷 1449-1454页

作者： A.F. Buckhorst M.K.B. do Canto R.J. Rabelo R.H. Schmitt Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University Campus-Boulevard 30 52074 Aachen Germany Department of Automation and Systems Engineering Federal University of Santa Catarina Florianópolis SC Brazil Fraunhofer Institute for Production Technology (IPT) Steinbachstrasse 17 52074 Aachen Germany

The Line-Less Mobile Assembly systems (LMAS) is a paradigm to maximize responsiveness to market trends by adaptive factory configurations utilizing mobile assembly resources. Such responsive systems are characterized as Holonic Manufacturing systems (HMS), whose Holonic Control Architectures (HCA) are portrayed as Industry 4.0-enabling approaches. Accordingly, we execute the ANEMONA methodology building the LMAS HCA. The analysis phase results in a use case specification. The design phase results in the architecture concept. The implementation phase results in a ontology, re-using elements from widespread manufacturing ontologies, and in the LMAS HCA. Validation is done by the execution of the desired use case workflow.

关键词： Line-Less Mobile Assembly systems Holonic Control Architecture Holonic Manufacturing systems Ontology Flexibility

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Technology assessment for digitalization in battery cell manufacturing 14

Technology assessment for digitalization in battery cell man...

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14th CIRP Conference on Intelligent Computation in Manufacturing engineering, CIRP ICME 2020

作者： Wanner, Johannes Bahr, Johannes Full, Johannes Weeber, Max Birke, Kai Peter Sauer, Alexander Fraunhofer Institute for Manufacturing Engineering and Automation IPA Nobelstrasse 12 Stuttgart70569 Germany Institute for Energy Efficiency in Production University of Stuttgart Nobelstrasse 12 Stuttgart70569 Germany Electrical Energy Storage Systems Institute for Photovoltaics University of Stuttgart Pfaffenwaldring 47 Stuttgart70569 Germany

The battery cell manufacturing is increasingly being digitalized to improve product quality and achieve a more transparent and efficient manufacturing process. In this paper, we apply the technology management method called "technology assessment"to the processes of electrical filling and formation of pouch cells to identify and evaluate possible digitalization measures. As a result, the digitalization measures in the process technology, logistics, quality control and energy system of the two processes are discussed and evaluated according to their potential and technology readiness level. The combination of digital twins of the battery cell with the digital factory operation is assessed as the most promising measure. © 2021 The Authors. Published by Elsevier B.V.

关键词： Electrolytes

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Causes of Catastrophic Forgetting in Class-Incremental Semantic Segmentation

arXiv

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arXiv 2022年

作者： Kalb, Tobias Beyerer, Jürgen Porsche Engineering Group GmbH Porschestraße 911 Weissach71287 Germany Fraunhofer Institute of Optronics Systems Technologies and Image Exploitation IOSB Germany Karlsruhe Institute of Technology Karlsruhe76131 Germany

Class-incremental learning for semantic segmentation (CiSS) is presently a highly researched field which aims at updating a semantic segmentation model by sequentially learning new semantic classes. A major challenge in CiSS is overcoming the effects of catastrophic forgetting, which describes the sudden drop of accuracy on previously learned classes after the model is trained on a new set of classes. Despite latest advances in mitigating catastrophic forgetting, the underlying causes of forgetting specifically in CiSS are not well understood. Therefore, in a set of experiments and representational analyses, we demonstrate that the semantic shift of the background class and a bias towards new classes are the major causes of forgetting in CiSS. Furthermore, we show that both causes mostly manifest themselves in deeper classification layers of the network, while the early layers of the model are not affected. Finally, we demonstrate how both causes are effectively mitigated utilizing the information contained in the background, with the help of knowledge distillation and an unbiased cross-entropy loss. Copyright © 2022, The Authors. All rights reserved.

关键词： Semantic Segmentation

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Highly Efficient, In-Band Pumped, Thulium-Doped Fibers in High-Power Amplifier and mJ Q-Switched Regime

Highly Efficient, In-Band Pumped, Thulium-Doped Fibers in Hi...

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Conference on Lasers and Electro-Optics Europe (CLEO EUROPE)

作者： Mathias Lenski Tobias Heuermann Martin Gebhardt Ziyao Wang Christopher Aleshire Christian Gaida César Jáuregui Jens Limpert Institute of Applied Physics Abbe Center of Photonics Friedrich-Schiller-Universität Jena Jena Germany Helmholtz-Institute Jena Jena Germany GSI Helmholtzzentrum für Schwerionenforschung Darmstadt Germany School of Engineering and Physical Sciences Heriot-Watt University Edinburgh UK Active Fiber Systems GmbH Jena Germany Fraunhofer Institute for Applied Optics and Precision Engineering Jena Germany

ISBN: (纸本)9798350345995

High-power, ultrafast, thulium-doped (Tm) fiber-laser systems operating at a center wavelength around 2 μm are very beneficial for various applications in metrology and sensing, as well as for frequency conversion techniques such as high- harmonic generation [1]. With longer pulses, in the ns-region, Tm-fiber lasers could be an ideal platform for laser-plasma sources due to their high beam quality [2]. With the state-of-the-art, ~790 nm cladding pumping of Tm-doped, fused silica fiber amplifiers, the achieved slope efficiencies are barely above 50 % for ultrafast pulse amplification [3–5]. Furthermore, in the ns-region, targeting energy extraction at mJ-levels, the efficiencies do not exceed more than 15 % [6]. In addition, due to the low quantum-efficiency, there is a high heat load generated that could cause thermal problems during high-power operation and, therefore, prevents scaling these systems beyond the kW-level [7]. The quantum-defect related limitations can be overcome by pumping Tm gain media directly in the upper laser level. For high-power CW operation, the most common approach is to pump Tm gain media around 1.55 μm or 1.9 μm, which has already demonstrated remarkable slope efficiencies [8], [9]. However, due to the high emission cross-section, the maximum storable energy at these pump wavelengths is quite low [10]. Therefore, a more suitable pump wavelength around 1.7 μm should be considered for highly energetic laser operation.

关键词： Harmonic generation Laser operation Silica fibers Thulium Thulium doped fiber lasers Thulium-doped fiber amplifiers

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Characterization of a Radially Emitting Spray Jet in a Cylindrical Inertial Electrostatic Confinement Plasma Source Based on Particle in Cell Simulation

SSRN

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SSRN 2024年

作者： Tiedemann, Dominik Hofmann, Patrick Herdrich, Georg Pflug, Andreas Emmerlich, Jens Müller, Matthias Ulrich, Sven Robert Bosch Manufacturing Solutions GmbH Wernerstraße 51 Stuttgart70469 Germany Karlsruhe Institute of Technology Institute for Applied Materials Hermann-vonHelmholtz-Platz 1 Eggenstein-Leopoldshafen76344 Germany Fraunhofer Institute for Surface Engineering and Thin Films IST Bienroder Weg 54 e Braunschweig38108 Germany Institute of Space Systems University Stuttgart Pfaffenwaldring 29 Stuttgart70569 Germany

This paper investigates the outflow mechanism of a cylindrical inertial electrostatic confinement plasma source using Particle in Cell plasma simulations. Various phenomena such as ion-wall interactions, impact ionization, excitation, and secondary electron generation are considered. together with a fine time and cell resolution to reveal relevant phenomena. The results indicate a high electron and ion density in front of the cathode at the widest grid opening, which suggests the formation of a cascade-like charge carrier emission, commonly referred to as the "spray jet". Initially, a virtual anode is formed within the cathode grid and is shifted toward the grid opening as time elapsed. Ions are accelerated in the plasma sheath around the cathode and collide with the cathode grids or oscillate through the grid opening. Electrons are accelerated and ionize the background gas at the plasma sheath edge. While the electron flow is disordered within the cathode it forms a cascade-like quasi-neutral plasma at the outlet of the plasma source. Through the formation of a virtual anode the discharge becomes self-sustained. With this simulation results the working principle of the inertial electrostatic confinement plasma source can be derived. © 2024, The Authors. All rights reserved.

关键词： Cathodes

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Multi-purpose high-resolution nanoscale table-top ptychography at 13.5 nm

Multi-purpose high-resolution nanoscale table-top ptychograp...

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Computational Optical Sensing and Imaging, COSI 2022

作者： Liu, C. Eschen, W. Loetgering, L. Schuster, V. Klas, R. Kirsche, A. Berthold, L. Iliou, A. Steinert, M. Pertsch, T. Hillmann, F. Krause, M. Limpert, J. Rothhardt, J. Helmholtz Institute Jena Fröbelstieg 3 Jena07743 Germany Institute of Applied Physics Abbe Center of Photonics Friedrich-Schiller-University Jena Albert-Einstein-Straße 15 Jena07745 Germany Leibniz Institute of Photonic Technology Albert-Einstein-Straße 9 Jena07745 Germany Fraunhofer Institute for Applied Optics and Precision Engineering IOF Albert-Einstein-Str. 7 Jena07745 Germany Fraunhofer Institute for Microstructure of Materials and Systems IMWS Walter-Hülse-Str. 1 Halle06120 Germany Adolf-Reichwein-Str. 23 Jena07745 Germany

We present our latest results on table-top ptychographic imaging at 13.5 nm. An overview and the identification of interesting areas are achieved with infrared illumination. XUV illumination provides sub-20-nm-resolut...

ISBN: (纸本)9781557528209

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Additive Manufacturing of Ceramics opens the door to Components for Biomanufacturing Applications with high Functionality

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Procedia CIRP 2024年 125卷 284-289页

作者： Uwe Scheithauer Stefan Holtzhausen Hajo Wiemer Fraunhofer Institute for Ceramic Technologies and Systems Group Additive and Hybrid Manufacturing Winterbergstr. 28 01277 Dresden Germany TUD Dresden University of Technology Institute of Machine Elements and Machine Design Chair of Virtual Product Development Group Advanced Geometric Modeling And Analysis 01062 Dresden Germany TUD Dresden University of Technology Institute of Mechatronic Engineering Chair of Machine Tools Development and Adaptive Controls Department of Machine Data Processing 01062 Dresden Germany

Significant advancements in production technology, materials, component design, and data science foster innovation across industries, including biomanufacturing. Ceramic materials, adapted additive manufacturing processes, and novel construction methods hold immense innovation potential due to ceramics’ exceptional thermal, chemical, and mechanical properties. Additive manufacturing enables the creation of intricate ceramic components with unprecedented functionality. Hybridizing manufacturing technologies and materials facilitates direct integration of additional features like sensors and actuators. Despite their potential, ceramic materials remain underutilized. This article aims to spark a discourse on leveraging high-performance ceramic components in biomanufacturing, leveraging superior material properties, innovative design methods, additive manufacturing, process data analysis, and AI.

关键词： ceramics: additive manufacturing component design data science biomanufacturing

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Identifying future district heating potentials in germany: a study using empirical insights and distribution cost analysis

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International Journal of Sustainable Energy Planning and Management 2024年 40卷 124-137页

作者： Manz, Pia Fleiter, Tobias Billerbeck, Anna Fritz, Markus Alibaş, Şirin Eichhammer, Wolfgang Fraunhofer Institute for Systems and Innovation Research Breslauer Str. 48 Karlsruhe76139 Germany Copernicus Institute of Sustainable Development University Utrecht Princetonlaan 8a Utrecht3584 Netherlands Faculty of Environment and Natural Resources University of Freiburg Tennenbacher Str. 4 Freiburg79106 Germany Faculty of Engineering University of Freiburg Georges-Köhler-Allee 101 Freiburg79110 Germany

District heating will play an important role in the transition towards climate-neutral heating. Various studies on modelling the energy system show that district heating and the related expansion of the networks can have different levels of importance. A main reason is that the costs for distribution grid expansion are not well or not at all considered and empirical evidence for a threshold for cost-effective distribution costs is missing in such studies. In this paper, we aim to improve empirical evidence allowing to improve the representation of future district heating expansion in energy systems models. For that, the current status of district heating is analysed in high spatial resolution for Germany. The results show that with the currently accepted average costs, a large range of the possible future market share of district heating for buildings between 17–52% is possible by 2050, with the parameters of the connection rate and the renovation rate of the building stock. We conclude that the district heating share could be increased by the factor of 2 to 5 in the future, proving the importance of climate-neutral district heating in the transition. © 2024, Aalborg University Press. All rights reserved.

关键词： District heating

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