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Toward Synthetic Physical Fingerprint Targets
Get PDFBiometric fingerprint identification hinges on the reliability of its sensors; however, calibrating and standardizing these sensors poses significant challenges, particularly in regards to repeatability and data diversity. To tackle these issues, we propose methodologies for fabricating synthetic 3D fingerprint targets, or phantoms, that closely emulate real human fingerprints. These phantoms enable the precise evaluation and validation of fingerprint sensors under controlled and repeatable conditions. Our research employs laser engraving, 3D printing, and CNC machining techniques, utilizing different materials. We assess the phantoms’ fidelity to synthetic fingerprint patterns, intra-class variability, and interoperability across different manufacturing methods. The findings demonstrate that a combination of laser engraving or CNC machining with silicone casting produces finger-like phantoms with high accuracy and consistency for rolled fingerprint recordings. For slap recordings, direct laser engraving of flat silicone targets excels, and in the contactless fingerprint sensor setting, 3D printing and silicone filling provide the most favorable attributes. Our work enables a comprehensive, method-independent comparison of various fabrication methodologies, offering a unique perspective on the strengths and weaknesses of each approach. This facilitates a broader understanding of fingerprint recognition system validation and performance assessment
Information Fusion and Hand Alignment to Improve Hand Recognition in Forensic Scenarios
Get PDFIn many forensic scenarios, criminals often attempt to conceal their identity by covering their face and other distinctive body parts. In such situations, physical evidence may, however, reveal other unique characteristics, e.g. hands, which can be used to identify offenders. In this context, several state-of-the-art biometric recognition systems have been proposed recently. These recognition systems offer high identification performance in restricted environments. However, in forensic scenarios, the environment is often unconstrained, making biometric identification considerably more difficult, with a consequent decrease in accuracy. In this article, we explore methods (e.g. hand alignment and information fusion) to improve the identification of subjects within forensic investigations. Experimental results show that explored techniques play an important role in the improvement of the identification performance of existing schemes: the combination of hand alignment and information fusion results in the highest Rank-1 identification performance improvement of up to 13.10% (i.e., 26.30% vs. 13.20%) and 16.30% (i.e., 77.00% vs. 60.70%) with respect to the baseline for the unconstrained databases NTU-PI_v1 and HaGRID, respectively ( https://github.com/ljsoler/IF-HA-HandRecognition )
Structures of Laminar Lean Premixed H2/CH4/Air Polyhedral Flames: Effects of Flow Velocity, H2 Content and Equivalence Ratio
Get PDFPolyhedral Bunsen flames, induced by hydrodynamic and thermo-diffusive instabilities, are characterized by periodic trough and cusp cellular structures along the conical flame front. In this study, the effects of flow velocity, hydrogen content, and equivalence ratio on the internal cellular structure of premixed fuel-lean hydrogen/methane/air polyhedral flames are experimentally investigated. A high-spatial-resolution one-dimensional Raman/Rayleigh scattering system is employed to measure the internal scalar structures of polyhedral flames in troughs and cusps. Planar laser-induced fluorescence of hydroxyl radicals and chemiluminescence imaging measurements are used to quantify the flame front morphology. In the experiments, stationary polyhedral flames with varying flow velocities from 1.65 to 2.50 m/s, hydrogen contents from 50 to 83%, and equivalence ratios from 0.53 to 0.64 are selected and measured. The results indicate that the positively curved troughs exhibit significantly higher hydrogen mole fractions and local equivalence ratios compared to the negatively curved cusps, due to the respective focusing/defocusing effect of trough/cusp structure on highly diffusive hydrogen. The hydrogen mole fraction and local equivalence ratio differences between troughs and cusps are first increased and then decreased with increasing measurement height from 5 to 13 mm, due to the three-dimensional effect of the flame front. With increasing flow velocity from 1.65 to 2.50 m/s, the hydrogen mole fraction and local equivalence ratio differences between troughs and cusps decrease, which is attributed to the overall decreasing curvatures in troughs and cusps due to the decreased residence time and increased velocity-induced strain. With increasing hydrogen content from 50 to 83%, the hydrogen mole fraction and local equivalence ratio differences between troughs and cusps are amplified, due to the enhanced effects of the flame front curvature and the differential diffusion of hydrogen. With increasing equivalence ratio from 0.53 to 0.64, a clear increasing trend in hydrogen mole fraction and equivalence ratio differences between troughs and cusps is observed at constant flow velocity condition, which is a trade-off result between increasing effective Lewis number and increasing curvatures in troughs and cusps
Mobile Contactless Fingerprint Presentation Attack Detection: Generalizability and Explainability
Get PDFContactless fingerprint recognition is an emerging biometric technology that has several advantages over contact-based schemes, such as improved user acceptance and fewer hygienic concerns. Like for most other biometrics, Presentation Attack Detection (PAD) is crucial to preserving the trustworthiness of contactless fingerprint recognition methods. For many contactless biometric characteristics, Convolutional Neural Networks (CNNs) represent the state-of-the-art of PAD algorithms. For CNNs, the ability to accurately classify samples that are not included in the training is of particular interest, since these generalization capabilities indicate robustness in real-world scenarios. In this work, we focus on the generalizability and explainability aspects of CNN-based contactless fingerprint PAD methods. Based on previously obtained findings, we selected four CNN-based methods for contactless fingerprint PAD: two PAD methods designed for other biometric characteristics, an algorithm for contact-based fingerprint PAD and a general-purpose ResNet18. For our evaluation, we use four databases and partition them using Leave-One-Out (LOO) protocols. Furthermore, the generalization capability to a newly captured database is tested. Moreover, we explore t-SNE plots as a means of explainability to interpret our results in more detail. The low D-EERs obtained from the LOO experiments (below 0.1% D-EER for every LOO group) indicate that the selected algorithms are well-suited for the particular application. However, with an D-EER of 4.14%, the generalization experiment still has room for improvement
Toward system innovation for more sustainable chemistry: insights into consumers’ perceptions, knowledge, and behavior related to traceability and product design strategies along leather supply chains
Get PDFThe leather industry is a complex system with multiple actors that faces a fundamental transition toward more sustainable chemistry. To support this process, this article analyzes challenges of the industry and consumers’ roles as a nexus of transition-relevant developments. We present findings of an empirical study (N = 439) among consumers on their perception of leather, related knowledge, and purchasing behavior. We found that participants perceived leather as natural, robust, and of high quality. Knowledge about the manufacturing of leather products was overall limited but varied. Applying a psychological behavior theory, we found that being aware of environmental and health consequences from conventional manufacturing of leather products was positively associated with a personal norm to purchase leather products that are less harmful to environment and health. The perceived ease of buying such products was positively associated with their purchase. Our findings shed light on consumers’ roles in the current leather system and their support of niche innovations toward more sustainable chemistry. Against this backdrop, we discuss implications for product design, consumer information, and needs for traceability along supply chains
Towards minimizing efforts for Morphing Attacks—Deep embeddings for morphing pair selection and improved Morphing Attack Detection
Get PDFFace Morphing Attacks pose a threat to the security of identity documents, especially with respect to a subsequent access control process, because they allow both involved individuals to use the same document. Several algorithms are currently being developed to detect Morphing Attacks, often requiring large data sets of morphed face images for training. In the present study, face embeddings are used for two different purposes: first, to pre-select images for the subsequent large-scale generation of Morphing Attacks, and second, to detect potential Morphing Attacks. Previous studies have demonstrated the power of embeddings in both use cases. However, we aim to build on these studies by adding the more powerful MagFace model to both use cases, and by performing comprehensive analyses of the role of embeddings in pre-selection and attack detection in terms of the vulnerability of face recognition systems and attack detection algorithms. In particular, we use recent developments to assess the attack potential, but also investigate the influence of morphing algorithms. For the first objective, an algorithm is developed that pairs individuals based on the similarity of their face embeddings. Different state-of-the-art face recognition systems are used to extract embeddings in order to pre-select the face images and different morphing algorithms are used to fuse the face images. The attack potential of the differently generated morphed face images will be quantified to compare the usability of the embeddings for automatically generating a large number of successful Morphing Attacks. For the second objective, we compare the performance of the embeddings of two state-of-the-art face recognition systems with respect to their ability to detect morphed face images. Our results demonstrate that ArcFace and MagFace provide valuable face embeddings for image pre-selection. Various open-source and commercial-off-the-shelf face recognition systems are vulnerable to the generated Morphing Attacks, and their vulnerability increases when image pre-selection is based on embeddings compared to random pairing. In particular, landmark-based closed-source morphing algorithms generate attacks that pose a high risk to any tested face recognition system. Remarkably, more accurate face recognition systems show a higher vulnerability to Morphing Attacks. Among the systems tested, commercial-off-the-shelf systems were the most vulnerable to Morphing Attacks. In addition, MagFace embeddings stand out as a robust alternative for detecting morphed face images compared to the previously used ArcFace embeddings. The results endorse the benefits of face embeddings for more effective image pre-selection for face morphing and for more accurate detection of morphed face images, as demonstrated by extensive analysis of various designed attacks. The MagFace model is a powerful alternative to the often-used ArcFace model in detecting attacks and can increase performance depending on the use case. It also highlights the usability of embeddings to generate large-scale morphed face databases for various purposes, such as training Morphing Attack Detection algorithms as a countermeasure against attacks
Inter-organisational human resource management and network orientation of worker representatives: a practice-based perspective
Get PDFWe develop a practice-based framework of inter-organisational human resource management that puts multi-employer work arrangements in inter-firm networks at its centre. By reinterpreting existing knowledge on multi-employer work arrangements and how they are managed, we delineate four processes in the assemblage of inter-organisational HR management. To illustrate the usefulness of our framework, we explore the question of whether and how an inter-organisational HR management develops in four exemplary cases of multi-employer work arrangements. These cases reveal that the quality and degree of inter-organisational HR management varies considerably, also depending on whether worker representatives show network awareness and orient their activities towards inter-organisational relations.Résumé
Les auteurs développent un cadre pratique de gestion des ressources humaines inter-organisationnelles qui privilégie les accords de travail multi-employeurs au sein de réseaux inter-entreprises. En procédant à une réinterprétation des connaissances existantes sur les modalités de travail multi-employeurs et sur la manière dont elles sont gérées, ils identifient quatre processus dans la mise en place d’une gestion inter-organisationnelle des ressources humaines. Pour illustrer l’utilité de ce cadre interprétatif, ils se demandent si et comment une gestion inter-organisationnelle des ressources humaines peut se développer dans quatre cas exemplaires d’accords de travail multi-employeurs. Ces cas révèlent que la qualité et le degré de gestion inter-organisationnelle des ressources humaines varient considérablement, selon que les représentants des travailleurs sont plus ou moins conscients de l’importance du réseau et orientent dès lors leur action dans le sens des relations inter-organisationnelles.Zusammenfassung
Wir entwickeln eine praxistheoretische Perspektive auf interorganisationales Human Ressource Management, in welcher Mehr-Arbeitgeber-Beziehungen in Unternehmensnetzwerken in den Vordergrund gestellt werden. Aus einer Reinterpretation des bisherigen Forschungsstands leiten wir vier Prozesse ab, in denen sich ein interorganisationales HR-Management konstituiert. Um den Gebrauchswert unseres Ansatzes zu illustrieren, ziehen wir vier Beispielfälle von Mehr-arbeitgeber-Beziehungen heran. Unsere Fälle zeigen auf, dass sowohl die Qualität als auch der Grad von interorganisationalem HR-Management variiert, und zwar auch in Abhängigkeit davon, ob die Interessenvertretungen der Beschäftigten ein hohes Maß an Netzwerkbewusstsein aufweisen und ihre Aktivitäten auf interorganisationale Beziehungen ausrichten
Proceedings CERC 2023
Get PDFIn an era marked by unprecedented technological advancements, the 2023 Collaborative European Research Conference (CERC) convened in Barcelona, Spain, on June 9-10, 2023, as a hybrid event. This gathering underscored the imperative of interdisciplinary collaboration across Europe, bringing together researchers from diverse fields to address the multifaceted challenges and opportunities presented by rapid innovation.
The conference featured a keynote address that delved into the swift evolution of artificial intelligence (AI) and its profound societal implications. The discourse highlighted the integration of AI across various professions, emphasizing the necessity for human oversight to navigate ethical considerations and mitigate potential risks. The keynote also examined the European Union's proactive stance on AI regulation, particularly through the forthcoming AI Act, which aims to establish a robust framework for the responsible development and deployment of AI technologies.
The proceedings encompass a wide array of research contributions, reflecting the conference's commitment to fostering knowledge transfer and interdisciplinary exchange. Topics span from data processing and machine learning to e-healthcare innovations and the societal impacts of emerging technologies. Notably, discussions on AI's role in healthcare, legal frameworks, and education underscore the critical need for ethical standards and regulatory measures to ensure that technological progress aligns with societal well-being
The potential of district heating in Germany from a sustainability perspective
Get PDFDistrict heating plays a key role in the German heat transition (“Wärmewende”) to achieve climate protection targets. In order to realise the heating transition, the legislator has established cost efficiency as a central criterion in the relevant legislation. Ecology, as the third pillar of sustainability, is thus taking a back seat, despite the transformation’s influence on other sustainability dimensions beyond climate protection.
The article takes an ecological perspective on the district heating
transformation and shows that, from this perspective, greater emphasis
should be placed on local environmental heat and large heat pumps.
In the second step, the decentralised information available on the
actual transformation plans of district heating suppliers is aggregated and evaluated at a national level for the first time. The evaluation indicates a possible gap between the developed sustainable target state and the plans of district heating suppliers, which are primarily focussed on the cost efficiency criterion. This comparison identifies a potential conflict of objectives between the legislative cost efficiency criterion and the ecological sustainability perspective
Millistructured Coiled Flow Inverter for Biphasic Continuous Flow 5‐Chloromethylfurfural Synthesis
Get PDFSyntheses of alternative platform chemicals, such as 5‐chloromethylfurfural (CMF), from bio‐based starting materials are often associated with complicated kinetic schemes and mass transfer processes. Millistructured flow reactor concepts can help to elucidate kinetic schemes and determine rate constants which are of crucial importance for the design of respective technical processes. For the first time, the influence of proton concentration on the rate constants involved in the biphasic synthesis of CMF is systematically investigated. Results are discussed in terms of green chemistry metrics