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Advanced Markov Modeling and Simulation for Safety Analysis of Autonomous Driving Functions up to SAE 5 for Development, Approval and Main Inspection
No full text104111The development, approval and recurring testing of driving assistance, partial and conditional automation (SAE levels 1 to 3) and, above all, high and full automation (4 to 5) requires an ever-increasing effort. At the same time, there is a lack of recognized sufficiently scalable general quantitative approaches in this area, in particular simulation methods including models, software and hardware up to vehicle-in-the-loop simulations, e.g. in the context of main inspection. In this context, the paper explores the potential of non-classical Markov modeling. First, it exemplifies how vehicles, drivers and other road users can be modeled for different driving scenarios using the Systems Modeling Language (SysML). Based on this model an abstract Markov diagram is presented. The two Markov simulation methods used operate on a discrete finite state space and allow for time-dependent state transitions. When compared to the matrix solver-based simulation, the Monte Carlo based simulation method is in principle extensible to state history-dependent as well as rule-based state transitions. Also, it allows to include subsystem simulation models. The extended Markov model allows to evaluate states with respect to functionality and safety, e.g. to determine whether it is sufficiently likely to reach fail operational states. It can also be used to determine dominant critical transitions and insufficient system resolution. In addition, numerous standardized safety and reliability measures are accessible. It will be shown how such a reference model can be quantified using simple failure models, as well as how it could be fed with further transition and failure models at different levels of abstraction using simulations as well as software tests data up to field test data. Finally, the paper hints at the potential of such an extended Markov modeling, especially with respect to an understandable and efficient safety verification in different product life cycle phases including after-sales
11. Stuttgarter Runder Tisch Forschung im Bevölkerungsschutz
No full textDer Stuttgarter Runde Tisch »Forschung im Bevölkerungsschutz« feierte in diesem Jahr sein 10-jähriges Bestehen - ein Meilenstein, der die anhaltende Bedeutung und den Erfolg dieser Plattform für den Austausch zwischen Praxis und Forschung im Bereich Bevölkerungsschutz unterstreicht. Seit seiner Gründung hat sich der Runde Tisch als Forum etabliert, um aktuelle Herausforderungen und Anforderungen aus der Praxis in die Forschung zu tragen und innovative Lösungsansätze zu entwickeln.
Das diesjährige Jubiläumstreffen stand unter dem Motto »Zukunftsfähig: Innovationen im Bevölkerungsschutz« und bot eine einzigartige Gelegenheit, sowohl auf die Errungenschaften der letzten Dekade zurückzublicken als auch den Blick nach vorne zu richten. In einer Zeit, in der der Bevölkerungsschutz vor immer komplexeren Herausforderungen steht, ist die Förderung von Innovationen und die enge Zusammenarbeit zwischen Forschung und Praxis von entscheidender Bedeutung.
Vertretende aus Behörden, Unternehmen, Rettungsdiensten und Forschungseinrichtungen kamen zusammen, um gemeinsam die Zukunft des Bevölkerungsschutzes zu gestalten. Durch den offenen Austausch und die Vernetzung verschiedener Akteure wurden nicht nur aktuelle Forschungsthemen vorgestellt und diskutiert, sondern auch neue Impulse für zukünftige Projekte und Kooperationen gesetzt
Fabrication of ultra-shallow EUV gratings in silicon via ion irradiation
No full textOperation of diffraction gratings at near-normal incidence in the extreme ultra violet range (EUV) requires ultra-shallow gratings. These are extremely challenging to produce via conventional dry etching techniques. As alternative, the approach presented here utilizes swelling caused by ion irradiation to fabricate ulta-shallow gratings. To increase the processing speed by at least one order of magnitude in comparison to direct write processes with focussed ion beams, we utilize a broad ion source which can structure areas in the range of tens of square-cm via irradiation through a mask of photoresist. Here, we focus on the irradiation of crystalline silicon with molecular nitrogen ions with an energy of 40 keV. By utilizing a variation in the conical angle of irradiation we fabricated structures with heights ranging from 1.7 nm to 5.5 nm, while maintaining stable source and irradiation conditions, highlighting a parameter for the tailoring of processing times. Next to that, a variation of non-conical angle of irradiation paths the way towards a fabrication of arbitrary gratings shapes. In combination, this enhances the control of structure height and shape in the angstrom range, which is highly relevant to applications in the EUV
Differential 45° Phase-Shifted Lo Signal Generation to Enable Subharmonic IQ Modulation for Broadband 6G Communication in the D-Band
No full text6568This work presents a broadband generation of 45° phase-shifted signals in the W-Band in a 90 nm SiGe BiCMOS technology. It is designed for IQ modulation in the D-Band, where the use of subharmonic system architectures is beneficial with regard to efficient signal generation. However, the subharmonic factor, which is two for this work, reduces the required phase shift for IQ modulators from 90° to 45°. Our approach utilizes an integrated Lange Coupler to generate 45° phase-shifted signals by adding the Lange Coupler's in-phase and quadrature output signals. Accepting a phase error of ± 5° a relative bandwidth of 51.5% is achieved at a center frequency of 83.5 GHz, which represents the highest published operating frequency for an integrated generation of a 45° phase shift. Embedded into a subharmonic IQ modulator, a sideband suppression of more than 25 dB is achieved over a bandwidth of 60 GHz, covering a large portion of the D band
Volatile Memory Motifs: Minimal Spiking Neural Networks
No full text8864988655How spiking neuronal networks encode memories in their different time and spatial scales constitute a fundamental topic in neuroscience and neuro-inspired engineering. Much attention has been paid to large networks and long-term memory, for example in models of associative memory. Smaller circuit motifs may play an important complementary role on shorter time scales, where broader network effects may be of less relevance. Yet, compact computational models of spiking neural networks that exhibit short-term volatile memory and actively hold information until their energy source is switched off, seem not fully understood. Here we propose that small spiking neural circuit motifs may act as volatile memory components. A minimal motif consists of only two interconnected neurons - one self-connected excitatory neuron and one inhibitory neuron - and realizes a single-bit volatile memory. An excitatory, delayed self-connection promotes a bistable circuit in which a self-sustained periodic orbit generating spike trains co-exists with the quiescent state of no neuron spiking. Transient external inputs may straightforwardly induce switching between those states. Moreover, the inhibitory neuron may act as an autonomous turn-off switch. It integrates incoming excitatory pulses until a threshold is reached after which the inhibitory neuron emits a spike that then inhibits further spikes in the excitatory neuron, terminating the memory. Our results show how external bits of information (excitatory signal), can be actively held in memory for a pre-defined amount of time. We show that such memory operations are robust against parameter variations and exemplify how sequences of multidimensional input signals may control the dynamics of a many-bits memory circuit in a desired way.1
Simulation Based Uncertainty Analysis for Radiation Pattern Measurements Using an Active Radar Module
No full textAntennas fully integrated in radar systems or even on the chip packages cannot be measured with a conventional antenna measurement system as there is no access to the antenna feed point. The two-way radiation pattern of a frequency modulated continuous wave (FMCW) radar system can be measured using the transmit and receive module of the radar itself while measuring against a reflector. Still, the measurement uncertainty differentiates from conventional antenna measurements, and detailed studies are missing. The uncertainty factors introduced by the mechanical system and the reflectors themselves like the size of the reflector and the mechanical misalignment of the reflector and antenna under test (AUT) are investigated within this study on the basis of simulations. As reference antenna the simulation model of a scalar feed horn antenna and a plate, a dihedral and a trihedral reflector are used. The results show an overall stable behavior and a low error for the evaluated mechanical misalignments
Vanadium telluride VTe2: a novel cathode for rechargeable aluminum batteries and its performance optimization
No full textVanadium telluride VTe2 has been successfully synthesized via hydrothermal reaction and characterized for the first time as a cathode for rechargeable aluminum batteries. The electrochemical activity of VTe2 originates from the redox pairs Te4+/Te2- and V5+/V4+. VTe2 delivers a first discharge capacity of 275 mAh g-1 at 100 mA g-1 vs. an Al anode. The charge transport within VTe2 is based on interaction with AlCl4- anions, while the charge storage mechanism is dominated by surface-controlled processes at low voltages and by diffusion-controlled processes at high voltages. However, VTe2 suffers a rapid, drastic capacity loss and a short cycle life (<100 cycles) due to the corrosive chloroaluminate electrolyte, which dissolves the cathode active material upon charging and causes the shuttle effect. Ti3C2Tx MXene (forming a composite with VTe2) and CMK-3 mesoporous carbon (embedded onto the separators) are used as strategies to avoid the shuttle effect of soluble species towards the anode. This enables the reversibility of the redox reaction, allowing VTe2 to develop a sustained electrochemical activity. VTe2/Ti3C2Tx composite with CMK-3 modified separators shows improved electrochemical performance over as-prepared VTe2: 63 mAh g-1 after 300 cycles vs. 10 mAh g-1 after 75 cycles at 100 mA g-1.66
Flurförderzeuge
No full textDieser Beitrag erläutert Flurförderzeuge zum Heben, Ziehen und Stapeln von Lasten. Er behandelt Einsatzbereiche, wichtige Typen, den technischen Aufbau, Aspekte der Nachhaltigkeit sowie relevante Normen und Regularien
Collaborative Perceiver: Elevating Vision-Based 3D Object Detection via Local Density-Aware Dense Spatial Occupancy
No full text4862Vision-based bird’s-eye-view (BEV) 3D object detection has advanced significantly in autonomous driving by offering cost-effectiveness and rich contextual information. However, existing methods often construct BEV representations by collapsing extracted object features, neglecting intrinsic environmental contexts, such as roads and pavements. This hinders detectors from comprehensively perceiving the characteristics of the physical world. To alleviate this, we introduce a multi-task learning framework, Collaborative Perceiver (CoP), that leverages spatial occupancy as auxiliary information to mine consistent structural and conceptual similarities shared between 3D object detection and occupancy prediction tasks, bridging gaps in spatial representations and feature refinement. To this end, we first propose a pipeline to generate dense occupancy ground truths incorporating local density information (LDO) for reconstructing detailed environmental information. Next, we employ a voxel-height-guided sampling (VHS) strategy to distill fine-grained local features according to distinct object properties. Furthermore, we develop a global-local collaborative feature fusion (CFF) module that seamlessly integrates complementary knowledge between both tasks, thus composing more robust BEV representations. Extensive experiments on the nuScenes benchmark demonstrate that CoP outperforms existing vision-based frameworks, achieving 49.5% mAP and 59.2% NDS on the test set
Assessing the variations in long-term photovoltaic yield prediction due to solar irradiance and module temperature
No full text976981To mitigate the financial investment risks for PV systems stakeholders, it is a prerequisite to reliably predict the long-term energy yield (LTYP). However, this is not usually the case due to several different influencing effects such as: solar resource, system design, the quality of the components as well as degradation. All these effects increase the uncertainties in LTYP. To improve the prediction accuracy, each of these effects should be separately explored. The main aim of this study is to assess the effects solar irradiance used a representative for LTYP. In the manuscript we show that using multi-years repetition approach that include year-to-year climate variability and solar irradiance brightening/dimming effects reduced the variations to ±2.1%. The effect of temperature correction in LTYP model led to variations between ±4.5% in comparison with a non-temperature corrected model but where highly dependent on a given location. Overall, it is shown that for more reliable predictions using the proposed approach, at least 5 years of historical data is needed