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This work presents the Multi-Bees-Tracker (MBT3D) algorithm, a Python framework implementing a deep association tracker for Tracking-By-Detection, to address the challenging task of tracking flight paths of bumblebees in a social group. While tracking algorithms for bumblebees exist, they often come with intensive restrictions, such as the need for sufficient lighting, high contrast between the animal and background, absence of occlusion, significant user input, etc. Tracking flight paths of bumblebees in a social group is challenging. They suddenly adjust movements and change their appearance during different wing beat states while exhibiting significant similarities in their individual appearance. The MBT3D tracker, developed in this research, is an adaptation of an existing ant tracking algorithm for bumblebee tracking. It incorporates an offline trained appearance descriptor along with a Kalman Filter for appearance and motion matching. Different detector architectures for upstream detections (You Only Look Once (YOLOv5), Faster Region Proposal Convolutional Neural Network (Faster R-CNN), and RetinaNet) are investigated in a comparative study to optimize performance. The detection models were trained on a dataset containing 11359 labeled bumblebee images. YOLOv5 reaches an Average Precision of AP = 53, 8%, Faster R-CNN achieves AP = 45, 3% and RetinaNet AP = 38, 4% on the bumblebee validation dataset, which consists of 1323 labeled bumblebee images. The tracker’s appearance model is trained on 144 samples. The tracker (with Faster R-CNN detections) reaches a Multiple Object Tracking Accuracy MOTA = 93, 5% and a Multiple Object Tracking Precision MOTP = 75, 6% on a validation dataset containing 2000 images, competing with state-of-the-art computer vision methods. The framework allows reliable tracking of different bumblebees in the same video stream with rarely occurring identity switches (IDS). MBT3D has much lower IDS than other commonly used algorithms, with one of the lowest false positive rates, competing with state-of-the-art animal tracking algorithms. The developed framework reconstructs the 3-dimensional (3D) flight paths of the bumblebees by triangulation. It also handles and compares two alternative stereo camera pairs if desired.
Electrolyte-insulator-semiconductor capacitors (EISCAP) belong to field-effect sensors having an attractive transducer architecture for constructing various biochemical sensors. In this study, a capacitive model of enzyme-modified EISCAPs has been developed and the impact of the surface coverage of immobilized enzymes on its capacitance-voltage and constant-capacitance characteristics was studied theoretically and experimentally. The used multicell arrangement enables a multiplexed electrochemical characterization of up to sixteen EISCAPs. Different enzyme coverages have been achieved by means of parallel electrical connection of bare and enzyme-covered single EISCAPs in diverse combinations. As predicted by the model, with increasing the enzyme coverage, both the shift of capacitance-voltage curves and the amplitude of the constant-capacitance signal increase, resulting in an enhancement of analyte sensitivity of the EISCAP biosensor. In addition, the capability of the multicell arrangement with multi-enzyme covered EISCAPs for sequentially detecting multianalytes (penicillin and urea) utilizing the enzymes penicillinase and urease has been experimentally demonstrated and discussed.
This article addresses the need for an innovative technique in plasma shaping, utilizing antenna structures, Maxwell’s laws, and boundary conditions within a shielded environment. The motivation lies in exploring a novel approach to efficiently generate high-energy density plasma with potential applications across various fields. Implemented in an E01 circular cavity resonator, the proposed method involves the use of an impedance and field matching device with a coaxial connector and a specially optimized monopole antenna. This setup feeds a low-loss cavity resonator, resulting in a high-energy density air plasma with a surface temperature exceeding 3500 o C, achieved with a minimal power input of 80 W. The argon plasma, resembling the shape of a simple monopole antenna with modeled complex dielectric values, offers a more energy-efficient alternative compared to traditional, power-intensive plasma shaping methods. Simulations using a commercial electromagnetic (EM) solver validate the design’s effectiveness, while experimental validation underscores the method’s feasibility and practical implementation. Analyzing various parameters in an argon atmosphere, including hot S -parameters and plasma beam images, the results demonstrate the successful application of this technique, suggesting its potential in coating, furnace technology, fusion, and spectroscopy applications.
Next-generation aircraft designs often incorporate multiple large propellers attached along the wingspan (distributed electric propulsion), leading to highly flexible dynamic systems that can exhibit aeroelastic instabilities. This paper introduces a validated methodology to investigate the aeroelastic instabilities of wing–propeller systems and to understand the dynamic mechanism leading to wing and whirl flutter and transition from one to the other. Factors such as nacelle positions along the wing span and chord and its propulsion system mounting stiffness are considered. Additionally, preliminary design guidelines are proposed for flutter-free wing–propeller systems applicable to novel aircraft designs. The study demonstrates how the critical speed of the wing–propeller systems is influenced by the mounting stiffness and propeller position. Weak mounting stiffnesses result in whirl flutter, while hard mounting stiffnesses lead to wing flutter. For the latter, the position of the propeller along the wing span may change the wing mode shapes and thus the flutter mechanism. Propeller positions closer to the wing tip enhance stability, but pusher configurations are more critical due to the mass distribution behind the elastic axis.
A novel method to determine the extruded length of a metallic wire for a directed energy deposition (DED) process using a microwave (MW) plasma jet with a straight-through wire feed is presented. The method is based on the relative comparison of the measured frequency response obtained by the large-signal scattering parameter (Hot-S) technique. In the practical working range, repeatability of less than 6% for a nonactive plasma and 9% for the active plasma state is found. Measurements are conducted with a focus on a simple solution to decrease the processing time and reduce the integration time of the process into the existing hardware. It is shown that monitoring a single frequency for magnitude and phase changes is sufficient to achieve good accuracy. A combination of different measurement values to determine the length is possible. The applicability to different diameter of the same material is shown as well as a contact detection of the wire and metallic substrate.
This paper investigates the interior transmission problem for homogeneous media via eigenvalue trajectories parameterized by the magnitude of the refractive index. In the case that the scatterer is the unit disk, we prove that there is a one-to-one correspondence between complex-valued interior transmission eigenvalue trajectories and Dirichlet eigenvalues of the Laplacian which turn out to be exactly the trajectorial limit points as the refractive index tends to infinity. For general simply-connected scatterers in two or three dimensions, a corresponding relation is still open, but further theoretical results and numerical studies indicate a similar connection.
06| Warum es gemeinsam besser geht
10| Interview
14| Wer ist hier der Boss?
18| Schnittstelle zwischen Mensch und Technik
22| Zweite Heimat Jülich
28| Zwischen Angst und Hoffnung
32| Eine Sternstunde für die FH Aachen
36| Gegen alle Widerstände
38| Ein Ort, der bleibt
42| Der Aufblühende
46| Der Computer sitzt am Steuer
52| Da geht das Herz auf
54| Hoch hinaus
58| Beratungsangebote
60| Das alte Schätzchen
CardboardCastle
(2024)
„CardboardCastle“ ist ein 3D-Animationsfilm. Der Film zeigt die lebendig gewordene Welt zweier Königreiche aus Pappe, die in einem Streit um einen magischen Zauberstab verwickelt sind. Das Projekt beweist, dass es möglich ist, mit der Software „Blender“ einen vollwertigen und hochwertigen 3D-Animationsfilm zu erstellen. Dabei wurden alle Assets bis auf Texturen selbst hergestellt. Die virtuelle Pappe spielt hierbei eine fundamentale Rolle, für diese wurde ein vollkommen neuer Workflow entwickelt, welcher es ermöglicht, realistische Pappe zu visualisieren. „CardboardCastle“ setzt auf eine cinematische Inszenierung von Licht und vereint technisches Wissen mit unterhaltenden Inhalten. Dabei zeigt er die kindliche Vorstellungskraft und lädt die Zuschauer ein, sich an ihre eigenen kindlichen Fantasien zu erinnern.
»Unerwünscht« widmet sich einer Art von architektonischer Gestaltung, die auf tückische Weise als »defensive Architektur« bezeichnet wird. In Form einer Zeitung bietet sie einen umfassenden Einblick in das Thema und gewährt einen vielseitigen Blick in eine Thematik, die im Interesse der Verantwortlichen lieber im Verborgenen geblieben wäre. Defensive Architektur bezeichnet strategische Baumaßnahmen in der Stadt- und Bauplanung, die darauf abzielen, unerwünschte Personengruppen durch unpraktisches oder unbequemes Design von bestimmten Orten fernzuhalten. Diese Maßnahmen richten sich beispielsweise gegen obdachlose Menschen, Jugendliche oder Skateboarder*innen. Die überwiegende Mehrheit der Bevölkerung ist sich weder der Existenz von solchen architektonischen Maßnahmen noch ihrer Auswirkungen auf das Leben der Betroffenen bewusst. »Unerwünscht« zielt darauf ab, diese Lücke in der öffentlichen Wahrnehmung zu schließen.
Budzi Budzi
(2024)
Mit über 1300 Büdchen in 86 Veedeln ist Köln Deutschlands Kiosk-Hauptstadt. Sie sind ein prägendes Element von Nachbarschaften und gehören zum Kölner Stadtbild einfach dazu wie der Dom und der Rhein. Durch Anekdoten, Interviews, Beiträge zur Popkultur, alte Fotografien, Momentaufnahmen und vertraute Grafiken sowie einer festen Formsprache entsteht das erste Büdchenmagazin für Köln. Das Periodikum erscheint alle drei Monate und liegt kostenfrei in den Büdchen aus. Es ist eine Publikation die beweist, dass Büdchen mehr als gängige Verkaufsstellen sind, sondern Knotenpunkte unserer Gesellschaft.