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Extraktion geschlossener Schiffs- und Objektkonturen mit 1-Pixel-Breite zur präzisen Segmentierung in Farb- und Infrarotbildern durch Deep Learning
No full textThis work focuses on the extraction of detailed and complex shapes of ships and other objects from RGB and thermal imagery. This task is important for accurate classification and identification and is not limited to maritime contexts. Ship segmentation from thermal imagery is particularly relevant to real-world maritime applications, but progress in this area is often not publicly available and generally lags behind RGB segmentation, underscoring the need for new benchmarks/datasets and methods. This study presents a new method for extracting 1-pixel wide, closed, highly detailed shapes using a novel object contour and edge detection technique. It achieves a state-of-the-art Optimal Dataset Scale (ODS) score of 0.752 on a refined PASCAL-val dataset and 0.824 on the BSDS500. Traditional post-processing with Non-Maximum Suppression (NMS) results in discontinuities in the contours, but the introduced Walk the Lines (WtL) algorithm overcomes this by extracting perfectly closed, detailed contours through a shallow CNN to ‘walk’ contour changes, making this approach both unique and innovative. Evaluations show that this method achieves higher IoU peaks with very high recall compared to existing methods, demonstrating the power and novelty of this approach. The WtL has the potential to partially replace NMS in computer vision, especially where runtime is not critical, thus avoiding negative artifacts while preserving details. In addition, WtL is a promising tool for creating highly detailed segmentations, especially when every detail counts and the object shapes are very challenging, which can also be the case in interdisciplinary imaging fields such as physics, medicine, and biology.Vo
Tracing the infrastructural unfolding of (edtech) events throughhybrid team ethnography
No full textThis is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/)This article contributes to expanding discussions on the rising hybridity of (edtech) events and, in conjunction to that, of ethnographic (edtech) event research. With hybridity, we point to the increasing postdigital condition of contemporary society. Even though such hybridity, and its methodological consequences for ethnographic research, are increasingly discussed, few attention has so far been put on how this hybridity manifests in, and is mediated through, orchestrations of data infrastructures. This article presents hybrid team ethnography as a way to study, and at the same time be intricately interwoven with, such infrastructure-mediated hybridity. Concretely, we report on an ethnography in which we studied an event in the edtech startup sector. Our findings showcase how researchers co-construct and are shaped by events, not just through dynamic interplays between physical presence-absence, but equally through data infrastructures and research(er) presentation. Moreover, they simultaneously showcase how edtech events unfold infrastructurally over space and time.HSU-O
From pixels to rating
No full textThis is an open access article under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/).While machine learning (ML) has advanced image‐based damage detection, a critical gap remains: the automated translation of detected damage into standardized condition ratings used in structural assessments. Most existing approaches stop at semantic segmentation, overlooking the damage rating step essential for practical inspections. This paper presents a semiautomated system that bridges this gap by linking multi‐label damage segmentation with condition rating prediction. Our contributions are: (1) a data‐driven label taxonomy for damage segmentation, derived from statistical and semantic analysis of 2.2 million inspection records, and designed to support downstream condition rating; (2) a pipeline for converting textual inspection records into structured training data for automated condition rating, and a set of custom bidirectional long short‐term memory (LSTM) models achieving up to F1‐score on this task; and (3) a reference system architecture integrating image segmentation and text‐based damage rating within an interactive 3D inspection interface. The system demonstrates how integrating damage detection and condition rating within an interactive 3D interface can streamline inspection documentation and enhance decision support for concrete structures. Developed in compliance with German inspection standards and designed for adaptability, the system architecture offers a transferable framework for embedding ML‐based automation into digital inspection workflows, ensuring that all components, from damage detection to condition rating, are aligned in an end‐to‐end process.Vo
Strombelastbarkeit von Energiekabeln: Einfluss saisonaler und klimabedingter Änderungen
No full textThis is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Climate change is influencing traditionally stable factors such as meteorological characteristics and soil conditions, impacting the planning process of electrical energy grids, especially energy cables. Supported by real-life data from the metropolitan region of Hamburg, this study examines the sensitivity of electric energy cables to seasonal and climate related changes, aiming to address inevitable future climate impacts. Using the thermal impedance model by the International Electrotechnical Commission, combined with 32 years of local soil and weather data, permissible current levels were calculated for a specific cable configuration. Comparisons with static boundaries reveal that shifts in environmental conditions can undermine the planning process, affecting maximum current limits and casting doubt on the current method’s validity. Analysis shows that seasonal transitions significantly alter soil parameters within each annual cycle, causing up to a 10 % variation in energy transfer potential, depending on soil, cable, and regional specifics. Static standards also overestimate ampacity by up to 12 % for the studied region and timeframe. Climate change leads to shifting soil and weather conditions, causing unused energy transfer capacities, overestimations, and potential structural damage. As climate effects intensify, both seasonal and historical shifts are expected to have greater impacts, highlighting the limitations of the current static planning model without additional monitoring systems. As limited transmission capacities increasingly demand costly congestion management and equipment redundancies diminish, the need to optimize current resources and plan for a changing future becomes even more critical.Vo
Discursive foundations for sustainable evaluation
No full textIn this paper, we contribute a differentiation of micro-institutional reasoning types to further develop discursive institutionalism within the larger fields of organizational theory, institutional theory, and social responsibility. Discursive institutionalism outlines the relevance of discourse in building institutions, their maintenance and change. However, the theory provides incomplete knowledge on micro-institutional foundations, especially with regard to individual discursive reasoning in economic contexts. Building on Habermasian discourse ethics, we identify pragmatic, ethical/moral and strategic types of reasoning in a bank’s institutional discourse relating to sustainable impact investment. Our contribution helps to better understand and further analyze the interplay between actors’ agency and their institutional context. We explain the challenges of discursive institution building and help to gain a better understanding of why institutional change in organizational contexts can be challenging or even failing when pragmatic, ethical, or moral reasoning collide with strategic interests. Our contribution is based on an empirical, qualitative, and longitudinal case study of a bank’s discursive development of a bundle of new institutions in the field of sustainable impact assessment. Our results inform theoretical debates about institution building, such as discursive institutionalism or strategic institutional entrepreneurship, as well as related literature concerned with organizational legitimacy. Moreover, our case study provides relevant insights for practitioners as it illustrates core challenges and opportunities for practical impact measurement and impact investment.A
Prototyping and evaluation of a fault-tolerant three-level TNPC inverter for aircraft propulsion
No full textThis paper presents the prototyping of a fault-tolerant three-level T-type Neutral Point Clamped (TNPC) inverter for electric aircraft propulsion systems. To enhance robustness against various semiconductor failures, disconnecting devices are integrated in series with both the high-side and low-side switches. However, this implementation also increases parasitic inductance in the commutation loop. To mitigate the challenges associated with a highly inductive commutation path, a DC snubber circuit is designed to suppress overvoltage and damp switching oscillations. The switching behavior is analyzed through double-pulse testing (DPT). Additionally, a three-phase, three-level inverter employing space vector pulse-width modulation (SVPWM) is implemented, and its performance under normal operating conditions is evaluated. Furthermore, post-fault operation is investigated when one phase is connected to the neutral point.Vo
Make it burn?
No full textThis is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)Vo
Steht der Nachweis tatsächlich erforderlicher Kosten im Widerspruch zur Kalkulationsfreiheit? – Eine baubetriebliche Einordnung
No full textDer Beitrag ist lizensiert unter der Creative Commons Attribution 4.0 International License (CC BY 4.0), http://creativecommons.org/licenses/by/4.0.Bei der Realisierung von Bauprojekten werden Bauleistungen selten in vollem Umfang genauso ausgeführt, wie sie ursprünglich geplant, ausgeschrieben und gar vertraglich vereinbart wurden. Folglich ist die Abwicklung von Bauverträgen gekennzeichnet durch Leistungsmodifikationen (und Leistungsstörungen) wie auch die Durchsetzung von Gestaltungs- bzw. Eingriffsrechten der Vertragspartner – besonders durch den Auftraggeber (AG). Hieraus resultierende Auswirkungen auf die Kosten etwaig betroffener Bauleistungen veranlassen den Auftragnehmer (AN) regel-mäßig zu Nachtragsforderungen. Die konsensuale Herbeiführung einer Vergütung für geänderte und/oder zusätzliche Leistungen kann durchaus langwierig und von hohem Konfliktpotential gekennzeichnet sein. Seit Inkrafttreten des Gesetztes zur Reform des „neuen“ Bauvertragsrechts zum 01.01.2018 hat sich dieser Umstand nicht zwingend verbessert. Vielmehr wurde durch § 650c BGB die Berechnungsmethodik für Mehrvergütungsansprüche grundlegend verändert. Resultierend aus einem uneinheitlichen Begriffsverständnis von „tatsächlich erforderlichen Kosten“ und „angemessenen Zuschlägen“ sehen sich die Vertragsparteien mit vermeintlich ausufernden (An-)Forderungen zur Nachtragsvergütung und -dokumentation konfrontiert. Vor diesem Hintergrund ergeben sich aus baubetrieblicher Sicht spannende Fragestellungen. Der vorliegende Beitrag gibt zunächst einen kurzen Überblick über die gesetzlichen Regelungen und die derzeit noch wenigen Vorgaben in der Rechtsprechung zum Umgang mit tatsächlich erforderlichen Kosten. Anschließend wird der Frage nachgegangen, ob den hieraus abzuleitenden Darlegungs- und Nachweisanforderungen überhaupt in praktikabler bzw. zumutbarer Weise nachgekommen werden kann.Vo
Fabrication of microchannels in lithium tantalate by selective etching of structures inscribed with a femtosecond laser
No full textOriginal content from this work may be used under the terms of the Creative Commons Attribution 4.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.Selective etching of material areas modified by femtosecond laser pulses in the volume of lithium tantalate has been applied to produce hollow microchannels. In a fully monolithic approach, microchannels up to 2.5 mm long with cross sections of 2.5 µm × 20 µm were etched into the crystal volume at a depth of 430 µm. The influence of the laser repetition rate, the pulse energy and the writing speed on the etching time and the etching selectivity was investigated as part of a systematic study. Characteristic process parameters, i.e. selectivity and diffusion coefficient were determined by fitting the etch depth versus time using a superdiffusion model. The obtained parameters are suitable for predicting the results of selective etching for certain process parameters, and thus enable the process to be controlled. A similar study was carried out in sapphire for comparison purposes.Vo