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Risikotechnologien in europäischen Mediendiskursen : Der korpuslinguistische Zugriff am Beispiel „Biotechnologie“
Get PDFIn diesem Beitrag wird exemplarisch vorgeführt, wie sprachstatistische Verfahren, die im Rahmen der sog. „Korpuslinguistik“ entwickelt werden, im Bereich der Risikoforschung eingesetzt werden können. Es wird gezeigt, wie einzelne Technologien in Medientexten als Risiken thematisiert werden und was daraus jeweils für die Konzeptualisierung von „Risiko“ folgt. Korpuslinguistische Verfahren ermöglichen einen großflächigen Zugriff auf sprachliche Ordnungsmuster, die mit der entsprechenden Heuristik als Spuren begrifflich gefasster Perspektiven auf Sachverhalte interpretiert werden können. Beispielhaft werden im folgenden Beitrag Korpusdaten zur Wahrnehmung von Grüner Gentechnik als Risikotechnologie aus der deutschen, englischen und italienischen Presse dargestellt. Dabei zeigt sich, dass der Risikobegriff jeweils Eigenheiten aufweist, die sich in einer je spezifischen Überlagerungssituation von nationalen Bewertungstraditionen und der je thematischen Technologie formieren. Durch den Einsatz der Korpuslinguistik lassen sich kollektive Einstellungen und Denkmuster zu Risiken nicht nur erahnen und am Einzelfall zeigen, sondern in ihrem Ausmaß und ihrer gesellschaftlichen Relevanz im Wortsinne ermessen. Auf diese Weise lassen sich verlässliche Daten über die Einstellung öffentlicher Akteure zu Risikotechnologien erheben und als Basis für gesellschaftliche, wissenschaftliche und politische Beratungen fruchtbar machen
Introducing the double validation metric for radar sensor models
No full textIn automated vehicles, environment perception is performed by various sensor types, such as cameras, radars, lidars, and ultrasonics. Simulation models of these sensors, as required in virtual validation methods, are available in various degrees of detail. However, proving the validity of such models is a subject of research. New metrics and methods for credibility assessment of simulation are needed to standardize the validation process in the future. The so-called double validation metric (DVM) has shown advantages and allows an intuitive interpretability of the validation results. The DVM has so far only been applied to lidar sensor models. In this paper, an extension to the DVM is introduced, which is called the DVM Map. A static measurement scenario is conducted in reality and transferred into simulation. The novel method is demonstrated on the obtained real and simulated radar sensor data. In this simple scenario special focus is put on the position accuracy of GNSS reference sensors. Therefore, their impact on the result of sensor model validation is discussed. The paper shows that the method provides a more detailed and accurate validation in comparison to the state of the art of a radar simulation, revealing previously undetected simulation errors. Errors due to the environment model, signal propagation, and signal processing are separated and satellite imagery is used for intuitive visualization of the results. This method is a complementary tool to existing validation techniques to improve the interpretability and judging the trustworthiness of radar simulations
Uptake of substances into living mammalian cells by microwave induced perturbation of the plasma membrane
Get PDFDelivering foreign molecules and genetic material into cells is a crucial process in life sciences and biotechnology, resulting in great interest in effective cell transfection methods. Importantly, physical transfection methods allow delivery of molecules of different chemical composition and are, thus, very flexible. Here, we investigated the influence of microwave radiation on the transfection and survival of mammalian cells. We made use of an optimized microwave-poration device and analyzed its performance (frequency and electric field strength) in comparison with simulations. We, then, tested the effect of microwave irradiation on cells and found that 18 GHz had the least impact on cell survival, viability, cell division and genotoxicity while 10 GHz drastically impacted cell physiology. Using live-cell fluorescence microscopy and image analysis, we tested the uptake of small chemical substances, which was most efficient at 18 GHz and correlated with electric field strength and frequency. Finally, we were able to obtain cellular uptake of molecules of very different chemical composition and sizes up to whole immunoglobulin antibodies. In conclusion, microwave-induced poration enables the uptake of widely different substances directly into mammalian cells growing as adherent cultures and with low physiological impact
Soil Indigenous Microbes Interact with Maize Plants in High-Arsenic Soils to Limit the Translocation of Inorganic Arsenic Species to Maize Upper Tissues
Get PDFArsenic (As) is a toxic metalloid that can enter the food chain through uptake by plants from soils followed by production of plant-based food. While soil–plant transfer of As in crops, especially rice, is relatively well studied, the role of soil microbes in As translocation in maize is not well understood. We performed a greenhouse pot experiment with maize plants grown at different soil As levels to study the role of soil microbes on uptake of different As species by maize. Three soil treatments with varying disturbance of the soil microbes (native soil, sterilized soil, and sterilized soil reconditioned with soil indigenous microbes) were intersected with three levels of As in soils (0, 100 and 200 mg kg⁻¹ spiked As, aged for 8 weeks) in a greenhouse experiment, where maize was grown for 5 months. Compared to uncontaminated soils, maize in high-As soils tended to accumulate more As in stems and less in leaves and grains, proportionally. Arsenic levels in stems were increased in sterilized soils due to the disturbance of the microbiome. The sterilization effects caused a phosphorus and manganese deficiency, leading to a higher As uptake in plants, that increased with rising As levels and resulted in a lower total dry biomass of the plants. In summary, this study highlights the role of soil indigenous microbes in limiting the uptake and translocation of inorganic As into maize. Compared to rice, cultivating maize plants in high-As soils is recommended
Safe hierarchical model predictive control and planning for autonomous systems
Get PDFPlanning and control for autonomous vehicles usually are hierarchically separated. However, increasing performance demands and operating in highly dynamic environments requires a frequent re-evaluation of the planning and tight integration of control and planning to guarantee safety, performance, and reliability. We propose an integrated hierarchical predictive control and planning approach to tackle this challenge. The planner and controller are based on repeated solutions of moving horizon optimal control problems. To increase flexibility and feasibility, the planner can choose different low-layer controller modes for increased flexibility and performance instead of using a single controller with a large safety margin for collision avoidance under uncertainty. Planning is based on simplified system dynamics and safety, yet flexible operation is ensured by constraint tightening based on a mixed-integer linear programming formulation. A cyclic horizon tube-based model predictive controller guarantees constraint satisfaction for different control modes and disturbances. Examples of different modes are slow-speed movement with high precision and fast-speed movements with large uncertainty bounds. Allowing for different control modes reduces conservatism, while the hierarchical decomposition of the problem reduces the computational cost and enables real-time implementation. We derive conditions for recursive feasibility to ensure constraint satisfaction and obstacle avoidance to guarantee safety and compatibility between the layers and modes. Simulation results illustrate the efficiency and applicability of the proposed hierarchical strategy
Dynamics of drop coalescence
No full textThe drop coalescence and spreading behavior of various fluids is important in many natural processes and industrial applications such as inkjet printing and coating processes.
Most of these processes involve complex fluids such as surfactants, polymer solutions and etc.
In order to optimize these processes, in-depth knowledge of the subject is required.
In the current work, I have studied the drop coalescence and spreading of these liquids using optical methods and other measurement techniques in addition to theoretical modeling.
In the chapter 4, the coalescence of two drops on a substrate was investigated.
In this scenario, one droplet has a lower surface tension than the other.
In this configuration, the droplet with lower surface tension will engulf the one with higher surface tension.
Under certain conditions, the coalescence of the droplets can become unstable and lead to fingering instability.
First place the droplet with higher surface tension, then place a second droplet with surface activity next to it.
The vapor of the second drop diffuses through the gas phase and reaches the first drop (initiate a Marangoni flow).
This induced flow pulls a thin film of second drop over the surface and make the drop coalescence unstable.
In the chapter 5, a new concept is introduced.
The drop coalescence of two drops is studied (by saturating the two liquids, we hinder the Marangoni flow).
The four-phase contact point is the contact point between two drops on a solid substrate in the gas phase.
We showed that the dynamics of the four-phase contact point behaves like the Lucas-Washburn equation inside a capillary (~√t).
By reducing the contact angle hysteresis (e.g. by performing the experiments on PDMS pseudo-brushes), we showed that the dynamics of the four-phase contact point changes (~ t^0.7).
In the chapter 6, we discussed the spreading and coalescence of non-Newtonian drops.
We showed that the ratio between the time scale of the experiment and the internal time scale of the material (elastocapillary number, Ec) is important for both cases of drop spreading and coalescence of polymer solutions.
We have shown that the spreading and coalescence exponents decrease with increasing elastocapillary number up to Ec ≈ 1.
The exponent increases sharply around Ec ≈ 1 and reaches a plateau and remains constant.
The results are compared to the viscous Newtonian case.
The interplay between wetting (drop spreading) and rheology for granular suspensions is also studied
Die Assemblierung und Stabilität ökologischer Gemeinschaften und Netzwerke
No full textTropische Regenwälder sind durch Abholzung bedroht. Sie können jedoch auf ehemaligen landwirtschaftlich genutzten Flächen nachwachsen. Störungen zu tolerieren und wesentliche Funktionen aufrecht zu erhalten sowie sich nach einer Störung schnell zu regenerieren, sind wesentliche Aspekte der Stabilität von Ökosystemeigenschaften. Die vorliegende Arbeit untersucht mittels theoretischer und empirischer Methoden die Stabilität und den Wiederaufbau (die Assemblierung) von ökologischen Gemeinschaften und Interaktionsnetzwerken zwischen Arten. Ein Fokus liegt auf mutualistischen Interaktionen, bei denen interagierende Arten beidseitig von der Interaktion profitieren, wie beispielsweise bei Pflanzen-Bestäuber-Netzwerken. Im ersten Projekt wird der Einfluss struktureller Eigenschaften von Pflanzen-Bestäuber-Netzwerken auf deren dynamische Stabilität (die Fähigkeit nach einer Störung in den Gleichgewichtszustand zurückzukehren) untersucht. Es wird gezeigt, dass die Komplexität (ein Maß für die Zahl an Arten und Verbindungen im Netzwerk) die dynamische Stabilität erhöht, die Nestedness (der Nischenüberlapp interagierender Arten) jedoch nicht. Das zweite Projekt befasst sich mit der Assemblierung mutualistischer Netzwerke. Der Fokus liegt auf dem Einfluss von Arten, die nur schwach von ihrem mutualistischen Partner im regenerierenden Habitat abhängen. Es wird gezeigt, dass diese Mutualisten die Geschwindigkeit und Vorhersagbarkeit der Assemblierung erhöhen. Im dritten Projekt wird die Resistenz (Wiederstandsfähigkeit gegenüber einer Störung), die Resilienz (Geschwindigkeit der Erholung) und die Regenerationszeit von 16 Organismengruppen in einem tropischen Regenwaldökosystem, das durch Abholzung zerstört wurde, errechnet. Es wird gezeigt, dass die Abundanz, Artenvielfalt und Artenzusammensetzung aller untersuchten Gruppen (außer Bakterien) innerhalb von 200 Jahren regeneriert. Zudem regenerieren mutualistisch interagierende Tiergruppen schneller als Bäume. Die Artenzusammensetzung benötigt länger für die Regeneration als die Artenvielfalt
und Abundanz und die Resilienz beeinflusst die Regenerationszeit stärker als die Resistenz. Die Ergebnisse dieser Arbeit zeigen die Wichtigkeit mutualistischer Netzwerke für die Stabilität und Regenerationsfähigkeit von biodiversen Ökosystemen wie Regenwäldern und weisen darauf hin, dass der Schutz dieser Netzwerke daher essentiell ist
The effect of slab touchdown on anticrack arrest in propagation saw tests
No full textUnderstanding crack phenomena in the snowpack and their role in avalanche formation is imperative for hazard prediction and mitigation. Many studies have explored how structural properties of snow contribute to the initial instability of the snowpack, focusing particularly on failure initiation within weak snow layers and the onset of crack propagation. This work addresses the subsequent stage, the effect of slab touchdown after weak-layer failure in mixed-mode loading (compressive anticrack (mode I) and shear (mode II) loading). Our results demonstrate that slab touchdown reduces the energy release rate, which can lead to crack arrest even under static conditions. This challenges the idea that only the dynamic properties of snow layers and spatial snowpack variations govern arrest, emphasizing instead the crucial role of mechanical interactions between the slab, weak layer, and base layer. By integrating these findings into the broader context of snowpack stability analysis, we contribute to a more nuanced understanding of avalanche initiation mechanisms. The analysis is provided in a comprehensive open-source model (https://github.com/2phi/weac, last access: 11 June 2025)
Force Sensor for Versatile Single-Step Sensor Integration in 3D-Printed Parts
No full textFused filament fabrication enables low-cost and highly adaptable production for industrial applications and the consumer market. Sensor integration requires individual development and production steps, increasing cost and limiting accessibility. 3D-printed sensors offer a low-cost alternative. Available approaches either adapt conventional sensors for additive manufacturing or offer individual solutions for every application. We present a universal force sensor that is directly integrated and encapsulated during the printing process. The design consists of two measurement grids based on the piezoresistive effect, in a half-bridge configuration. Only commercially available conductive filament is used. The sensor geometry includes electrical connections and contact interfaces, thus, enabling a full encapsulation inside the target body. The function is examined by measurements on various test bodies, exhibiting a small linearity error of 3.6 % and the ability to compensate temperature influences. We demonstrate the capa-bilities in a customized robotic gripper, where the sensor is able to detect whether the grasping operation was successful through contact force measurements. Our approach offers a straightforward solution for integrating force sensing capabilities into 3D-printed parts by simplifying the design process to a drag-and-drop operation in any design software
Client aware adaptive federated learning using UCB-based reinforcement for people re-identification
No full textPeople re-identification enables locating and identifying individuals across different camera views in surveillance environments. The surveillance data contains personally identifiable information such as facial images, behavioral patterns, and location data, which can be used for malicious purposes such as identity theft, stalking, or discrimination. This raises serious ethical and privacy concerns. The communication overhead of transporting a large number of data needed to train a global model and the diverse nature of the data from different sources are serious limitations facing the development of people re-identification technologies. We address these challenges by proposing a novel three-step federated learning framework. First, we investigate the impact of data augmentation techniques on the model generalizability and explore the effectiveness of different backbone networks. Second, we use reinforcement learning-based Upper Confidence Bounds (UCB) as a client-selection strategy in the federated round that dynamically chooses devices similar to the current model state, ensuring the model is updated with relevant data and enables faster convergence. Finally, we introduce a feature-level attention mechanism focusing on discriminative features for re-identification. Extensive experiments were conducted on nine benchmark re-ID datasets. The proposed framework outperformed the federated re-ID baseline by 10% in rank-1 accuracy and achieved results comparable to the centralized approach, with a difference of 2%. This improvement over the previous state-of-the-art establishes a new benchmark for federated re-identification