Publication Server of Hochschule Darmstadt
Not a member yet
259 research outputs found
Sort by
Praxisbuch Energiewirtschaft. Energieumwandlung, -transport und -beschaffung, Übertragungsnetzausbau und Kernenergieausstieg
Get PDFRezension, keine Zusammenfassung verfügba
Privacy Preserving Workload Reduction in Biometric Systems
Get PDFThe development of large-scale biometric identification systems that provide privacy protection of the enrolled subjects is an ongoing concern. Most importantly, biometric technologies demand interoperability and deployment assuring maximum usability by including multi-modal biometric solutions. In the context of privacy protection, several Biometric Template Protection (BTP) schemes have been proposed in the past. However, these schemes appear to be unsuitable for indexing (Workload Reduction (WR)) in biometric identification systems. As a consequence, they have been utilised in biometric identification systems performing exhaustive searches (i. e. one-to-many search), which represent a time-consuming task and, hence, a high computational workload dominated by the number of comparisons.
Additionally, novel privacy protection schemes have recently been developed in the literature. These approaches appear promising, but have not yet been evaluated in a detailed way, especially in terms of their privacy protection capabilities. Motivated by the acceleration of large-scale protected biometric database searches and the investigation for privacy enhancement, this thesis investigates in more detail indexing schemes operating on protected templates for different biometric characteristics, as well as some limitations in privacy protection. Extensive experimental evaluations demonstrate that novel BTP-agnostic and biometric characteristic (BC)-agnostic indexing schemes can successfully reduce the computational workload of a biometric system, while preserving biometric security and performance. Novel attacks have also been proposed in the context of privacy protection
Development of a novel testing concept for combined characterisation of tensile and compressive properties
Get PDFA novel material testing concept is developed in order to provide tensile and compressive properties within a single mechanical test. A new specimen geometry is designed for testing in a universal testing machine. Under tensile load, both a homogeneous tensile stress condition as well as a homogeneous compressive stress condition occur in the specimen. Measurements accompanying the experimental test with digital image correlation provide tensile and compressive Poisson’s ratio as well as tensile modulus. These properties are input parameters for subsequent finite element simulations. The compressive modulus is determined by iteratively adjusting finite element simulations in order to couple experimental and simulated results. For validating the concept, experimental tests are carried out on polyoxymethylene. While the tensile Poisson’s ratio of the new concept shows the best agreement with the reference value, the compressive modulus is approximately 15% higher. Further work should focus on an appropriate material model in order to reduce the deviation
Hybride Direktkommunikation als Unterstützung für sicherheitskritische Anwendungsfälle der Vehicle-to-X Kommunikation
Get PDFDie Arbeit beschäftigt sich mit der Untersuchung von Konzepten zur parallelen Verwendung unterschiedlicher Übertragungstechnologien für die direkte Kommunikation zwischen Verkehrsteilnehmern. Bei der V2X-Kommunikation können Nachrichten zwischen Verkehrsteilnehmern ausgetauscht werden, um z.B. vor Gefahrenstellen oder drohenden Konflikten zu warnen. Durch einen hybriden Einsatz unterschiedlicher Übertragungstechnologien soll die Qualität und die Zuverlässigkeit des Informationsaustausches gesteigert werden. Ziel ist die Erarbeitung von Konzepten, die die Eigenschaften der jeweiligen Technologien
kombinieren, um besonders bei zeit- bzw. sicherheitskritischen Verkehrssituationen eine Verbesserung der Verfügbarkeit von Informationen zu erreichen. Dies bezieht sich im Schwerpunkt auf die Anforderungen hinsichtlich Kommunikationsreichweite, Latenzzeiten bei der Datenübertragung und Reduzierung bzw. Vermeidung von Überlastsituationen auf einzelnen Übertragungskanälen. Die dynamische und situationsabhängige Organisation der Kommunikation unter Verwendung mehrerer Übertragungswege steht im Mittelpunkt der Betrachtung. Darüber hinaus werden auch Aspekte, wie die Einbindung von vulnerablen Verkehrsteilnehmern, wie Fuÿgängern oder Radfahrern, betrachtet. Die erarbeiteten Konzepte werden anhand konkreter Szenarien hinsichtlich ihres Potentials bei der Unterstützung sicherheitskritischer Anwendungsfälle untersucht. Hierfür wird eine Simulationsumgebung verwendet, welche sowohl die Verkehrsräume und deren Umfeld wie auch die Übertragungstechnologien und verwendeten Funkkanäle implementiert. Hierbei kommen auch stochastische Übertragungsmodelle zum Einsatz, die im Rahmen von Messungen im realen Verkehrsraum erstellt wurden.The thesis deals with the investigation of concepts for the parallel use of different transmission technologies for direct communication between road users. With V2X communication, messages can be exchanged between road users, for example, to warn of danger spots or imminent conflicts. The hybrid use of different transmission technologies is intended to increase the quality and reliability of information exchange. The aim is to develop concepts that combine the characteristics of the respective technologies to achieve an improvement in the availability of information, particularly in time- and safety-critical traffic situations. This relates in particular to the requirements regarding communication range, latency in data transmission and the reduction or avoidance of congestion situations on individual transmission channels. The dynamic and situation-dependent organization of communication using several transmission
channels is the focus of the investigation. In addition, aspects such as the involvement of vulnerable road users such as pedestrians or cyclists are also considered. The developed concepts are examined based on concrete scenarios about their potential in supporting safety-critical applications. For this purpose, a simulation environment is used, which implements the traffic spaces and
their surroundings as well as the transmission technologies and radio channels used. Stochastic transmission models are also used, which have been created as part of measurements in real traffic space
Integral recovery of an urban watershed through the implementation of nature-based solutions
Get PDFUnplanned urban expansion in Latin America has profoundly disturbed the natural hydrological processes of watersheds, particularly in tropical regions with extreme weather conditions. This has resulted in substantial runoff volumes, necessitating extensive engineering interventions to avoid damage. Urbanization has led not only to flooding problems, but also to a lack of recreational spaces for residents and an ecological degradation, negatively affecting the watersheds health. This study shows a methodology for creating scenarios making use of available sites for Nature-based-Solutions (NbS). Taking account of existing land cover, the methodology harnesses NbS multifunctionality to achieve hydrological, ecological and social benefits counteracting the threats to the health of a 23 km 2 urban tropical watershed located in Costa Rica. In these scenarios, suitable public roads in residential areas were used as sites for implementing permeable pavement, bioretention cells, infiltration trenches and street planters, while appropriate flat roofs and car parks were converted into green roofs and permeable pavements in industrial areas. In addition, several green public spaces were transformed into multifunctional storage areas. Hydrological and hydraulic modeling was used to evaluate the performance of each scenario, while the increase in green area of each scenario was used as an indicator of the ecological and social benefits. The concurrent implementation of the residential, industrial and green space scenarios provides an area available for NbS of 165.3 ha (7.2% of the watershed area), potentially leading to a decrease of up to 63.7% in peak flow and up to 46.2% in runoff volume for a specific rainfall event. As haphazard urban growth is a common feature of most urban watersheds in Latin America, this methodology, based on the use of different land cover types to create scenarios for NbS implementation, is transferable to and adaptable for other tropical urban watersheds
Machbarkeitsstudie zur Nutzung von Wärmepumpen auf dem Mathildenhügel in Darmstadt
Get PDFFür das Erreichen der Klimaneutralität 2045 in Deutschland hat die Bundesregierung 2022 ein Gesetz vorgelegt, welches Kommunen ab 20.000 Einwohner verpflichtet einen kommunalen Wärmebedarfsplan aufzustellen. Eine Wärmebedarfsplan beinhaltet den aktuellen, sowie den zukünftigen Wärmebedarf der Kommune. Außerdem werden Potenziale für die Erzeugung erneuerbarer Energien mit Wärmepumpen ermittelt (Landes Energie Agentur Hessen, 2024). Aus den Potenzialen lassen sich innerhalb der Kommune stadtteil-/ oder gebäudespezifisch Teilmaßnahmen für eine mögliche Umsetzung ableiten. Diese Maßnahmen bestehen aus Sanierungen, dem Aufbau und der Erweiterung von Wärmeverbundlösungen und spezifische Einzellösungen. Zudem dient die Potenzialermittlung einer zukünftigen effizienten Koordination von Planung, Umsetzung und Förderung. Über die Stadtwerke können die Kommunen zielgerichtet Wärmenetze neu bauen oder ausbauen (Landes Energie Agentur Hessen, 2020)
Zeit für Veränderung
Get PDFDer Beitrag nimmt unter Bezugnahme auf die Beiträge des Schwerpunkts „Staatliche Anerkennung“ einen Ausblick zur Perspektive der staatlichen Anerkennung vor und formuliert drei Impulse, die zu einer Neujustierung rund um Fragen der Qualifizierung von Sozialarbeiter_innen und Sozialpädagog_innen beitragen könnten
Design and synthesis of peptides as stabilizers of histone deacetylase 4
Get PDFHistone deacetylase 4 (HDAC4) contributes to gene repression by complex formation with HDAC3 and the corepressor silencing mediator for retinoid or thyroid hormone receptors (SMRT). We hypothesized that peptides derived from the class IIa specific binding site of SMRT would stabilize a specific conformation of its target protein and modulate its activity. Based on the SMRT‐motif 1 (SM1) involved in the interaction of SMRT with HDAC4, we systematically developed cyclic peptides that exhibit Ki values that are 9 to 56 times lower than that of the linear SMRT peptide. The peptide macrocycles stabilize the wildtype of the catalytic domain of HDAC4 (cHDAC4) considerably better than its thermally more stable ‘gain‐of‐function’ (GOF) variant, cHDAC4‐H976Y. Molecular docking and mutagenesis studies indicated that the cyclic peptides bind in a similar but not identical manner as the linear SMRT peptide to a discontinuous binding site. Ion mobility mass spectrometry showed no major changes in the protein fold upon peptide binding. Consistent with these results, preliminary hydrogen‐deuterium exchange mass spectrometry measurements indicated only minor conformational changes. Taken together, the cyclic SMRT peptides most likely stabilize the apo form of cHDAC4
Privacy-Preserving Multi-Biometric Indexing Based on Frequent Binary Patterns
Get PDFThe development of large-scale identification systems that ensure the privacy protection of enrolled subjects represents a major challenge. Biometric deployments that provide interoperability and usability by including efficient multi-biometric solutions are a recent requirement. In the context of privacy protection, several template protection schemes have been proposed in the past. However, these schemes seem inadequate for indexing (workload reduction) in biometric identification systems. More specifically, they have been used in identification systems that perform exhaustive searches, leading to a degradation of computational efficiency. To overcome these limitations, we present an efficient privacy-preserving multi-biometric identification system that retrieves protected deep cancelable templates and is agnostic with respect to biometric characteristics and biometric template protection schemes. To this end, a multi-biometric binning scheme is designed to exploit the low intra-class variation properties contained in the frequent binary patterns extracted from different types of biometric characteristics. Experimental results reported on publicly available databases using state-of-the-art Deep Neural Network (DNN)-based embedding extractors show that the protected multi-biometric identification system can reduce the computational workload to approximately 57% (indexing up to three types of biometric characteristics) and 53% (indexing up to two types of biometric characteristics), while simultaneously improving the biometric performance of the baseline biometric system at the high-security thresholds. Code is available at https://github.com/dosorior/FBP-Multi-biometric-Indexing
Impact of Occlusion Masks on Gender Classification from Iris Texture
Get PDFGender classification on normalized iris images has been previously attempted with varying degrees of success. In these previous studies, it has been shown that occlusion masks may introduce gender information; occlusion masks are used in iris recognition to remove non-iris elements. When, the goal is to classify the gender using exclusively the iris texture, the presence of gender information in the masks may result in apparently higher accuracy, thereby not reflecting the actual gender information present in the iris. However, no measures have been taken to eliminate this information while preserving as much iris information as possible.
We propose a novel method to assess the gender information present in the iris more accurately by eliminating gender information in the masks. This consists of pairing iris with similar masks and different gender, generating a paired mask using the OR operator, and applying this mask to the iris. Additionally, we manually fix iris segmentation errors to study their impact on the gender classification.
Our results show that occlusion masks can account for 6.92% of the gender classification accuracy on average. Therefore, works aiming to perform gender classification using the iris texture from normalized iris images should eliminate this correlation