TY - CHAP A1 - De, Sangita A1 - Niklas, Michael A1 - Rooney, Brian A1 - Mottok, Jürgen A1 - Brada, Premek T1 - Towards Semantic model-to-model Mapping of Cross-Domain Component Interfaces for Interoperability of Vehicle Applications : An Approach towards Synergy Exploration T2 - MDE4IoT & ModComp 2019: Model-Driven Engineering for the Internet of Things (MDE4IoT) & Interplay of Model-Driven and Component-Based Software Engineering (ModComp); joint proceedings of the Workshop on Model-Driven Engineering for the Internet of Things (MDE4IoT) & of the Workshop on Interplay of Model-Driven and Component-Based Software Engineering (ModComp); co-located with the IEEE/ACM 22nd International Conference on Model Driven Engineering Languages and Systems (MODELS 2019), Munich, Germany, September 15 and 17, 2019 N2 - With the increase in demand of services in the automotive industry, automotive enterprises prefer to collaborate with other qualified cross-domain partners to provide complex automotive functions (or services), such as autonomous driving, OTA (Over The Air) vehicle update, V2X (Vehicle-to-Vehicle communication), etc. One key element in cross-domain enterprise collaboration is the mutual agreement between interfaces of software components. In this context, model-to-model mappings of software component models of heterogeneous frameworks for automotive services and to explore the synergies in their interface semantics, have become an essential factor in improving the interoperability among the automotive and other cross-domain enterprises. However, one of the challenges in achieving cross-domain component interface model-to-model mappings at an application level lies in detecting the interface semantics and the semantic relations that are conveyed in different component models in different frameworks. This paper addresses this challenge using a Model Driven Architecture (MDA) based analytical approach to explore interface semantic synergies in the cross-domain component meta-models that are used for automotive services. The approach applies manual semantic checking measurements at an application interface level to understand the meanings and relations between the different meta-model entities of cross-domain framework software components. In this research, we attempt to ensure that interface description models of software components from heterogeneous frameworks can be compared, correlated and re-used for automotive services based on semantic synergies. We have demonstrated our approach using component meta-models from cross-domain enterprises, that are used for the automotive application domain. Y1 - 2019 UR - https://ceur-ws.org/Vol-2442/paper8.pdf U6 - https://doi.org/10.13140/RG.2.2.28765.15840 PB - RWTH Aachen CY - Aachen ER - TY - CHAP A1 - Renner, Sebastian A1 - Pozzobon, Enrico A1 - Mottok, Jürgen ED - Li, Wenjuan ED - Furnell, Steven ED - Meng, Weizhi T1 - The Final Round: Benchmarking NIST LWC Ciphers on Microcontrollers T2 - Attacks and Defenses for the Internet-of-Things, 5th International Workshop, ADIoT 2022: Copenhagen, Denmark, September 30, 2022, Revised Selected Papers N2 - In this work, we present our benchmarking results for the ten finalist ciphers of the Lightweight Cryptography (LWC) project initiated by National Institute of Standards and Technology (NIST). We evaluate the speed and code size of various software implementations on five different platforms featuring four different architectures. Moreover, we benchmark the dynamic memory utilization of the remaining NIST LWC algorithms on one 32-bit ARM controller. We describe our test cases and methodology and provide some information regarding the design and properties of the finalists before showing and discussing our results. Altogether, we evaluated almost 300 implementations of the 3rd round candidates and pick the most appropriate and best (primary) implementation of each cipher for our comparisons. We include a variant of AES-GCM in our benchmarking in order to be able to compare the state-of-the-art to the novel LWC ciphers. Our research gives an overview over the performance of the latest software implementations of the NIST LWC finalists and shows under which circumstances which candidate is performing the best in our individual test cases. Additionally, we make all benchmarking results, the code for our test framework and every tested implementation available to the public to ensure a transparent testing process. Y1 - 2022 SN - 978-3-031-21311-3 U6 - https://doi.org/10.1007/978-3-031-21311-3_1 SP - 1 EP - 20 PB - Springer Nature CY - Cham ER - TY - CHAP A1 - Renner, Sebastian A1 - Pozzobon, Enrico A1 - Mottok, Jürgen ED - Li, Wenjuan ED - Furnell, Steven ED - Meng, Weizhi T1 - Evolving a Boolean Masked Adder Using Neuroevolution T2 - Attacks and Defenses for the Internet-of-Things, 5th International Workshop, ADIoT 2022: Copenhagen, Denmark, September 30, 2022, Revised Selected Papers N2 - The modular addition is a popular building block when designing lightweight ciphers. While algorithms mainly based on the addition can reach very high performance, masking their implementations results in a huge penalty. Since efficient protection against side-channel attacks is a requirement in lots of use cases, we focus on optimizing the Boolean masking of the modular addition. Contrary to recent related work, we target evolving a masked full adder instead of parts of a parallel prefix adder. We study how techniques typically found in neural network evolution and genetic algorithms can be adapted in order to help in evolving an efficiently masked adder. We customize a well-known neuroevolution algorithm, develop an optimized masked adder with our new approach and implement the ChaCha20 cipher on an ARM Cortex-M3 controller. We compare the performance of the protected neuroevolved implementation to solutions found by traditional search methods. Moreover, the leakage of our new solution is validated by a t-test conducted with a leakage simulator. We present under which circumstances our masked implementation outperforms related work and prove the feasibility of successfully using neuroevolution when searching for complex Boolean networks. Y1 - 2022 SN - 978-3-031-21310-6 U6 - https://doi.org/10.1007/978-3-031-21311-3_2 SP - 21 EP - 40 PB - Springer Nature CY - Cham ER - TY - JOUR A1 - Shamonin (Chamonine), Mikhail A1 - Snarskii, Andrei A. A1 - Zhenirovskyy, M. I. T1 - Effective magnetic permeability of ferromagnetic composites. Theoretical description and comparison with experiment JF - NDT & E International N2 - Two analytical methods based on the so-called local linearization of magnetostatic properties of composite materials with ferromagnetic inclusions in a non-magnetic matrix are described. These methods are applied to the experimental data obtained in Gorkunov et al. [Russ. J. Nondestruct. Test. 3 (2001) 186]. A qualitative agreement is obtained for the concentration values reported in that paper and a quantitative agreement is achieved at slightly different value of concentration. The conclusions are supported by direct numerical modeling. KW - Material characterization KW - Ferromagnetic composites KW - Magnetostatic properties Y1 - 2004 U6 - https://doi.org/10.1016/j.ndteint.2003.08.001 VL - 37 IS - 1 SP - 35 EP - 40 PB - Elsevier ER - TY - JOUR A1 - Lukyanets, S. A1 - Snarskii, Andrei A. A1 - Shamonin (Chamonine), Mikhail A1 - Bakaev, V. V. T1 - Calculation of magnetic leakage field from a surface defect in a linear ferromagnetic material: an analytical approach JF - NDT & E International N2 - A novel analytical approach for calculating the magnetic leakage field from surface defects is proposed and demonstrated for the case of a linear ferromagnetic material. The novelty of the theory is that it relates the distribution of induced magnetic charges to the surface shape. An excellent agreement between the analytical and numerical results is shown. The functional relations between different magnetic field components are discussed. KW - Magnetic methods KW - Flux leakage KW - Mathematical model KW - Defects Y1 - 2003 U6 - https://doi.org/10.1016/S0963-8695(02)00071-3 VL - 36 IS - 1 SP - 51 EP - 55 PB - Elsevier ER - TY - JOUR A1 - Bakaev, V. V. A1 - Snarskii, Andrei A. A1 - Shamonin (Chamonine), Mikhail T1 - The permeability and remanent magnetization of a randomly inhomogeneous two-phase medium JF - Technical Physics N2 - A randomly inhomogeneous composite consisting of two, ferromagnetic and nonmagnetic (para-or diamagnetic), phases is considered. The dependence of the effective permeability of the composite on the concentration of the ferromagnetic phase and on the applied magnetic field is found for the case of the negligible hysteresis loop. When the hysteresis loop is appreciable, the remanent magnetization as a function of the ferromagnet concentration is calculated. KW - Magnetic Field KW - Permeability KW - Hysteresis Loop KW - Remanent Magnetization KW - Applied Magnetic Field Y1 - 2002 U6 - https://doi.org/10.1134/1.1435901 VL - 47 SP - 125 EP - 128 PB - Springer ER - TY - JOUR A1 - Shamonin (Chamonine), Mikhail A1 - Shamonina, Ekaterina A1 - Kalinin, V. A1 - Solymar, L. T1 - Properties of a metamaterial element: Analytical solutions and numerical simulations for a singly split double ring JF - Journal of Applied Physics N2 - An equivalent circuit, consisting of bulk and distributed elements, is derived for describing the properties of a potential metamaterial element capable of providing negative effective permeability. It is the singly split double ring (SSDR), a special case of the split ring resonator (J. B. Pendry et al., IEEE Trans. Microwave Theory Tech. 47, 2075 (1999)), obtained when the gap capacitance in the inner ring is infinitely large. The variables are the inter-ring voltage and the currents flowing in the inner and outer rings. The excitation is assumed in the form of a spatially constant temporally varying magnetic field. The functions, showing the angular variation of the variables, are found by solving a set of differential equations with boundary conditions imposed at the position of the split. It is shown from the analytical solution that the SSDR can have resonant frequencies in the full spectrum from very low to very high frequencies. It is pointed out in particular that whenever the mean diameter of the ring is equal to an odd multiple of the half wavelength it is always possible to find a set of parameters which will give rise to resonance. As examples the resonant frequencies are determined for eight sets of parameters. Results are also derived by replacing the distributed circuit with a number of discrete circuits. It is finally shown that the results obtained from the equivalent circuit model are in excellent agreement with those derived from the MICRO-STRIPES numerical package which solves Maxwell’s equations in the time domain. Y1 - 2004 U6 - https://doi.org/10.1063/1.1652251 VL - 95 IS - 7 PB - AIP ER - TY - JOUR A1 - Snarskii, Andrei A. A1 - Shamonin (Chamonine), Mikhail A1 - Zhenirovskyy, M. I. T1 - Effective properties of macroscopically non-uniform ferromagnetic composite materials BT - Theory and numerical experiment JF - Zhurnal Eksperimental'noj i Teoreticheskoj Fiziki - Journal of Experimental and Theoretical Physics (JETP) Y1 - 2003 VL - 123 IS - 1 SP - 79 EP - 92 PB - Akademija Nauk SSSR CY - Moscow ER - TY - JOUR A1 - Apelsmeier, Andreas A1 - Schmauss, Bernhard A1 - Shamonin (Chamonine), Mikhail T1 - Compensation of parasitic losses in an extrinsic fiber-optic temperature sensor based on intensity measurement JF - Sensors and Actuators A: Physical N2 - A method of referencing in an extrinsic optical fiber sensor system utilizing temperature dependence of the absorption edge in a semiconductor crystal (semi-insulating iron-doped indium phosphide) is demonstrated. The intensity reference is provided by controlling the temperature of an LED source and transmission measurements with different emission spectra. A transient operation regime is introduced. The entire process is controlled by a microprocessor unit. The performance of the sensor system is investigated and it is shown that the connector losses may be compensated for. Contrary to the published works performed with GaAs crystals it was not observed that the absorption coefficient of the semiconductor follows the law for idealized direct-gap semiconductor but can be described by the so-called Urbach tail. Since the proposed sensor system comprises a single LED source, simple electronics and no optical fiber couplers it is promising for realization of low-cost fiber-optic temperature sensors, e.g. for power transformer monitoring or magnetic resonance imaging applications. KW - Extrinsic optical fiber sensor KW - Temperature measurement KW - Intensity measurement KW - Intensity referencing KW - Indium phosphide KW - Transient operation Y1 - 2012 U6 - https://doi.org/10.1016/j.sna.2011.10.015 VL - 173 IS - 1 SP - 49 EP - 54 ER - TY - JOUR A1 - Trautner, Ralph A1 - Schmauss, Bernhard A1 - Shamonin (Chamonine), Mikhail T1 - Herstellung und Charakterisierung eines extrinsischen faseroptischen Elementarsensors zur Temperaturmessung JF - tm - Technisches Messen N2 - Es werden Herstellung und Charakterisierung eines faseroptischen Elementarsensors zur Temperaturmessung vorgestellt. Der Sensorkopf in Form eines Prismas aus Indiumphosphid nutzt die Temperaturabhängigkeit der Absorptionskante des Halbleitermaterials. Aufgrund der Abmessungen des Prismas im Grenzbereich von Feinmechanik zu Mikrosystemtechnik ist ein angepasstes Herstellungsverfahren notwendig. T2 - Manufacture and Characterization of an Extrinsic Elementary Fiber-Optical Sensor for Temperature Measurement KW - Extrinsic fiber optic sensor KW - indiumphosphide KW - temperature measurement KW - manufacturing method KW - characterization Y1 - 2008 U6 - https://doi.org/10.1524/teme.2008.0866 VL - 75 IS - 10 PB - De Gruyter ER - TY - JOUR A1 - Sydoruk, O. A1 - Radkovskaya, Anna A. A1 - Zhuromskyy, Oleksandr A1 - Shamonina, Ekaterina A1 - Shamonin (Chamonine), Mikhail A1 - Stevens, Chris J. A1 - Faulkner, Grahame A1 - Edwards, David J. A1 - Solymar, L. T1 - Tailoring the near-field guiding properties of magnetic metamaterials with two resonant elements per unit cell JF - PHYSICAL REVIEW B N2 - A theoretical and experimental study of magnetic metamaterials with unit cells containing two resonant elements is presented. The properties of these structures, consisting of split rings, are governed by strongly anisotropic magnetic coupling between individual elements. This coupling leads to propagation of slow magnetoinductive waves in the vicinity of the resonant frequency. The wavelength of magnetoinductive waves is much smaller than the free-space wavelength of the electromagnetic radiation. This opens up the possibility of manipulating the near field on a subwavelength scale. We develop a theoretical formulation for coupled chains of metamaterial elements allowing the tailoring of their guiding properties in the near field. In a comprehensive analysis modes of coupled waveguides supporting forward and/or backward waves are identified and the corresponding hybridization mechanisms for dispersion equations of magnetoinductive waves are determined. Analytical predictions are verified both experimentally and numerically on a variety of coupled waveguides. The approach can be employed for the design of near-field manipulating devices. Y1 - 2006 U6 - https://doi.org/10.1103/PhysRevB.73.224406 VL - 73 IS - 22 PB - APS ER - TY - JOUR A1 - Hesmer, Frank A1 - Tatartschuk, Eugen A1 - Zhuromskyy, Oleksandr A1 - Radkovskaya, Anna A. A1 - Shamonin (Chamonine), Mikhail A1 - Hao, Tong A1 - Stevens, Chris J. A1 - Faulkner, Grahame A1 - Edwards, David J. A1 - Shamonina, Ekaterina T1 - Coupling mechanisms for split ring resonators: Theory and experiment JF - Physica status solidi b N2 - We study experimentally and theoretically coupling mechanisms between metamaterial elements of the split ring resonator (SRR) type. We show that, depending on the orientation of the elements relative to each other, the coupling may be either of magnetic or electric type or a combination of both. Experimental results on SRRs with resonances around 1.7–1.9 GHz agree quantitatively with results of simulations (CST Microwave Studio). Further simulations provide analysis for a variety of SRRs both in the GHz and in the 20 THz frequency regions. The variety of coupling mechanisms can be employed in designing near field manipulating devices based on propagation of slow waves. Y1 - 2007 U6 - https://doi.org/10.1002/pssb.200674501 VL - 244 IS - 4 SP - 1170 EP - 1175 PB - Wiley ER - TY - JOUR A1 - Klank, Michael A1 - Hagedorn, Oliver A1 - Holthaus, Carsten A1 - Shamonin (Chamonine), Mikhail A1 - Dötsch, Horst T1 - Characterization and optimization of magnetic garnet films for magneto-optical visualization of magnetic field distributions JF - NDT & E International N2 - Rare-earth iron garnet films with in-plane anisotropy grown on (111)-oriented substrates can be used as magneto-optical indicator films for visualization of magnetic leakage fields in nondestructive evaluation. The influence of Faraday rotation, Faraday ellipticity, absorption and film thickness on the performance of a magneto-optical indicator film is investigated. A new optimization method is introduced and compared with the method of contrast optimization. The theory is experimentally verified and an application example is presented. KW - Magneto-optics KW - Imaging KW - Magnetic flux leakage KW - Garnet films Y1 - 2003 U6 - https://doi.org/10.1016/S0963-8695(03)00012-4 VL - 36 IS - 6 SP - 375 EP - 381 PB - Elsevier ER - TY - JOUR A1 - Lukyanets, S. A1 - Snarskii, Andrei A. A1 - Shamonin (Chamonine), Mikhail A1 - Bakaev, V. V. T1 - Calculation of magnetic leakage field from a surface defect in a linear ferromagnetic material: an analytical approach JF - NDT & E International N2 - A novel analytical approach for calculating the magnetic leakage field from surface defects is proposed and demonstrated for the case of a linear ferromagnetic material. The novelty of the theory is that it relates the distribution of induced magnetic charges to the surface shape. An excellent agreement between the analytical and numerical results is shown. The functional relations between different magnetic field components are discussed. KW - Magnetic methods KW - Flux leakage KW - Mathematical model KW - Defects Y1 - 2003 U6 - https://doi.org/10.1016/s0963-8695(02)00071-3 VL - 36 IS - 1 SP - 51 EP - 55 PB - Elsevier ER - TY - JOUR A1 - Bakaev, V. V. A1 - Snarskii, Andrei A. A1 - Shamonin (Chamonine), Mikhail T1 - The permeability and remanent magnetization of a randomly inhomogeneous two-phase medium JF - Technical Physics N2 - A randomly inhomogeneous composite consisting of two, ferromagnetic and nonmagnetic (para-or diamagnetic), phases is considered. The dependence of the effective permeability of the composite on the concentration of the ferromagnetic phase and on the applied magnetic field is found for the case of the negligible hysteresis loop. When the hysteresis loop is appreciable, the remanent magnetization as a function of the ferromagnet concentration is calculated. Y1 - 2002 U6 - https://doi.org/10.1134/1.1435901 VL - 47 IS - 1 SP - 125 EP - 128 PB - Springer ER - TY - JOUR A1 - Bakaev, V. V. A1 - Snarskii, Andrei A. A1 - Shamonin (Chamonine), Mikhail T1 - The effective magnetic permeability of a two-phase fibred ferromagnetic composite JF - Technical Physics Y1 - 2001 U6 - https://doi.org/10.1134/1.1427995 VL - 46 IS - 12 SP - 1571 EP - 1574 PB - Springer ER - TY - CHAP A1 - De, Sangita A1 - Mottok, Jürgen A1 - Brada, Premek ED - Miraz, M.H. ED - Southall, G. ED - Ali, Maaruf ED - Ware, A. T1 - Evaluation of Semantic Interoperability of Automotive Service API Models Based on Metamodels Similarity Metrics Using a Semi-automated Approach T2 - iCETiC 2022 : 5th International Conference on Emerging Technologies in Computing 2022: Aug 15, 2022 - Aug 16, 2022, Chester, UK N2 - In recent years, mapping of application software components’ ontologies semantically emerged as a big research challenge in automotive application domain that manipulates several cross-enterprise synergy knowledge application frameworks. The same knowledge formalized by different experts in different vehicle application frameworks leads to heterogeneous representations of components’ interface data. Consequently, this causes the most daunting impediment in semantic interoperability between the service components in cooperative automotive systems. From a modeling perspective, in the absence of standardized domain-based unified modeling techniques, the orchestration and resolution of semantic data interoperability between various vehicle application frameworks’ components’ interface models remain a challenge. However, this challenge could be addressed using ontological metamodeling by specifying semantic associations between components’ interface model concepts based on the domain knowledge. Apart from the semantic mapping of interface ontological metamodels, this work also defines quality metrics to determine the degree of semantic alignment achieved between the various interface ontologies. Additionally, to reduce development time and cost towards semantic interoperability, this work proposes a semi-automated plugin tool for the applicability of the evaluated quality metrics to semantic mapping of real-world components’ interface models. KW - Framework KW - Interface KW - Metamodel KW - Metrics KW - Ontology KW - Semantic Y1 - 2023 U6 - https://doi.org/10.1007/978-3-031-25161-0_2 SP - 14 EP - 28 PB - Springer CY - Cham ER - TY - JOUR A1 - Sterner, Michael A1 - Bauer, Franz T1 - Power-to-X im Kontext der Energiewende und des Klimaschutzes in Deutschland JF - Chemie-Ingenieur-Technik N2 - Um den Einfluss verschiedener Power-to-X-Verfahren auf die Transformation des deutschen Energiesystems und das Erreichen der Klimaschutzziele zu überprüfen, wurde ein sektorübergreifendes Energiesystemmodel entwickelt. Die daraus gewonnenen Ergebnisse zeigen: Für eine erfolgreiche Energiewende ist der Einsatz von Power-to-X in Zukunft unverzichtbar. Vor allem in Bereichen und Sektoren, in denen hohe Energiedichten erforderlich und nur wenig andere Optionen zur Defossilisierung vorhanden sind, werden Power-to-X-Technologien zwingend notwendig. T2 - Power-to-X in Context of Energy Transition and Climate Change Mitigation in Germany KW - Power-to-Gas KW - Climate mitigation KW - Energy system KW - Modeling KW - Power-to-X KW - Klimaschutz KW - Energiewende Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-11669 SN - 0009-286X N1 - Corresponding author: Franz Bauer VL - 92 IS - 1-2 SP - 85 EP - 90 PB - Wiley ER - TY - CHAP A1 - Rasp, Franziska A1 - Sahinbas, Burak A1 - Reisinger, Thomas A1 - Hipp, Susanne A1 - Leitgeb, Erich T1 - From Ray Tracing to Channel Impulse Responses: A Review on the Description of Polarimetric Time-Invariant SISO Channels T2 - 2024 International Conference on Broadband Communications for Next Generation Networks and Multimedia Applications (CoBCom), 09-11 July 2024, Graz, Austria N2 - One key enabler of autonomous driving is vehicle-to-everything (V2X) communication and positioning using cellular technologies. To design a vehicular localization system, the understanding and modeling of the physical radio channel (RC) is crucial. Polarization is an important yet often overlooked parameter of the RC. The combined polarization of the transmitting and receiving antennas, along with the environment, significantly affects the Channel Impulse Response (CIR) and localization performance. This paper aims to provide a deterministic description of the time-invariant Single-Input Single-Output (SISO) RC with focus on its polarimetric properties. The aim is to link the understanding of physical wave propagation directly to the conventional CIR descriptions used in localization and signal processing. The focus is on SISO RC modeling for arbitrary antennas, including Line-of-Sight (LoS) and multiple reflections. This study intentionally excludes diffraction, diffuse scattering, and bandwidth limitations, yet establishes a foundational frame-work for future multi-antenna systems with full polarimetric capabilities. The paper describes wave propagation using the Jones Calculus to separate polarimetric wave components, and models the polarimetric reception typical of RC modeling methods in positioning. This approach allows for the calculation of received signal at the antenna feed point. The application context of this research is in ranging or positioning within the V2X framework. KW - Channel Modeling KW - Ray Tracing KW - Wave Propagation KW - Friis KW - Jones Calculus KW - Polarization Diversity Y1 - 2024 SN - 979-8-3503-8845-9 U6 - https://doi.org/10.1109/CoBCom62281.2024.10631174 SN - 2834-8265 SP - 1 EP - 8 PB - IEEE ER - TY - CHAP A1 - Fuhrmann, Thomas A1 - Niemetz, Michael T1 - Ideas on Digitally Supported Individualization of Teaching and Learning for Evolving Competency Requirements T2 - Ninth International Conference on Higher Education Advances (HEAd 23), València, June 19, 2023 – June 22, 2023 N2 - The world is changing rapidly, mainly due to the digitalization of all areas of living. A huge amount of information is accessible via the Internet, and since it is no longer possible for individual humans to keep track of it, artificial intelligence (AI) is analyzing this data. In this rapidly changing world, students have to be educated for a successful career during their whole working life. These boundary conditions lead to completely new challenges for the education of students that are unprecedented in this form. Digitalization in education can help to cope with these challenges but can only be a means, not a goal. Personal interaction with students remains the most important task in education to address individual weaknesses and further develop strengths and talents. With the increasing amount of openly available information and the consequently increasing diversity of experiences within the group of students, differentiation is advancing to become the key to successful education. Digitization can help with this challenging task and support communication between students and their experienced instructors. But computers cannot replace human interaction and attempts to improve teaching efficiency by replacing this communication with electronic means endangers the learning success for complex concepts. This article analyzes education demands and possibilities for digitally supported teaching and learning. KW - Digitalization KW - higher education KW - student competencies KW - differentiation Y1 - 2023 U6 - https://doi.org/10.4995/HEAd23.2023.16232 SN - 2603-5871 SP - 1399 EP - 1406 PB - Universitat Polit`ecnica de Val`encia ER - TY - CHAP A1 - Rasp, Franziska A1 - Eberlein, Ernst A1 - Perner, Bastian A1 - Roth-Mandutz, Elke A1 - Hipp, Susanne T1 - Enhanced 5G Sidelink Ranging Based on Carrier Aggregation T2 - 2023 13th International Conference on Indoor Positioning and Indoor Navigation (IPIN), Nuremberg, Germany, 25-28 September 2023 N2 - Radio access network based positioning and ranging technologies become more and more important for autonomous driving. Positioning on the 5G Sidelink (SL) is discussed in Release 18 (2022-2024) of the Third Generation Partnership Project. For accurate timing-based ranging, a high temporal and spatial resolution is fundamental. The bandwidth for 5G SL positioning is limited due to sharing the existing SL resources with communication. Therefore, we send the positioning reference signal on two separate Component Carriers, i.e. we use a fragmented spectrum. We introduce a two step algorithm for estimating the time of arrival using the inflection point method. We proved a fragmented spectrum can achieve the same accuracy as a continuous spectrum. KW - Sidelink KW - 5G mobile communications KW - Distance measurement KW - Ranging KW - Positioning Y1 - 2023 SN - 9798350320114 U6 - https://doi.org/10.1109/IPIN57070.2023.10332548 SP - 1 EP - 6 PB - IEEE ER - TY - CHAP A1 - Grabinger, Lisa A1 - Hauser, Florian A1 - Mottok, Jürgen T1 - Evaluating Graph-based Modeling Languages T2 - Proceedings of the 5th European Conference on Software Engineering Education, Seeon/Germany, June 19 - 21, 2023 N2 - As humans, we tend to use models to describe reality. Modeling languages provide the formal frameworks for creating such models. Usually, the graphical design of individual model elements is based on subjective decisions; their suitability is determined at most by the prevalence of the modeling language. With other words: there is no objective way to compare different designs of model elements. The present paper addresses this issue: it introduces a systematic approach for evaluating the elements of graph-based modeling languages comprising 14 criteria – derived from standards, usability analyses, or the design theories ‘Physics of Notations’ and ‘Cognitive Dimensions of Notations’. The criteria come with measurement procedures and evaluation schemes based on reasoning, eye tracking, and questioning. The developed approach is demonstrated with a specific use case: three distinct sets of node elements for causal graphs are evaluated in an eye tracking study with 41 subjects. Y1 - 2023 SN - 978-1-4503-9956-2 U6 - https://doi.org/10.1145/3593663.3593664 SP - 120 EP - 129 PB - ACM ER - TY - CHAP A1 - Hauser, Florian A1 - Grabinger, Lisa A1 - Mottok, Jürgen T1 - Something Short Gets Even Shorter: Adapting the LIST-K for the Use in an Online Learning Management System T2 - Proceedings of the 5th European Conference on Software Engineering Education, Seeon/Germany, June 19 - 21, 2023 N2 - This study examines how Klingsieck’s LIST-K questionnaire [22] can be shortened and adapted to the requirements of an online learning management system. In a study with 213 participants, the questionnaire is subjected to an exploitative factor analysis. In a next step, the results are evaluated in terms of their reliability. This process creates a modified factor structure for the LIST-K, comprising a total of eight factors. The reliability of the modified questionnaire is at an α of .770. The shortened version of the LIST-K questionnaire is currently being used on an experimental basis in different courses. Y1 - 2023 SN - 978-1-4503-9956-2 U6 - https://doi.org/10.1145/3593663.3593684 SP - 65 EP - 72 PB - ACM ER - TY - JOUR A1 - De, Sangita A1 - Premek, Brada A1 - Mottok, Jürgen T1 - Derivation of Optimized Threshold of Semantic Alignment Metrics for Intepretation of Interoperability and Reusability of Cross-enterprise Vehicle Service Interface Models JF - Informatica N2 - Over the past decade, cars have turned gradually into real cyber physical systems. The collaboration of services between the service-oriented, cross-enterprise vehicle application frameworks has increased to generate novel, smart and complicated vehicle services. Consequently, from an interoperability perspective, semantically mapping of vehicle service component’s interface ontological models emerged as a big research interest in automotive application domain that manipulates several cross-enterprise synergy knowledge applications frameworks. The ontological metamodeling lays the foundation for building semantic bridge and exploring semantic associations between service components’ interface models based on the domain knowledge for semantic interoperability. Also, several semantic quality metrics has been defined over time for the vehicle service interface ontological metamodels. The empirically evaluated values of these metrics can be used to assess progress in cross-enterprise interoperability between the service and the clients’ APIs ontological models in vehicle domain. Despite potential benefits of semantic alignment quality metrics, the effective use of these metrics for vehicle service interface ontologies have proven elusive. Yes, such metrics can be used successfully for quantification, but then they mostly fail to provide adequate annotations in subsequent decision-making in the direction of semantic interoperability and reusability. The effective use of ontology semantic alignment quality metrics is basically hindered in the absence of the meaningful thresholds. In fact, the absence of an effective and meaningful threshold for the semantic similarity measure between various vehicle service interface ontological metamodels, motivates this research work which not only proposes a design approach to an optimized threshold for the semantic similarity metrics but also applies this threshold on few defined semantic alignment quality metrics. This paper also uses a real-world vehicle domain industrial case study to illustrate the design approach. KW - interface KW - automotive services KW - semantic KW - metrics KW - optimized threshold KW - framework KW - metamodels KW - ontologies Y1 - 2023 U6 - https://doi.org/10.31449/inf.v47i7.4739 SN - 0350-5596 VL - 47 IS - 7 PB - Slovenian Society Informatika ER - TY - JOUR A1 - Kral, Christian A1 - Haumer, Anton A1 - Kapeller, Hansjörg A1 - Pirker, Franz T1 - Design and Thermal Simulation of Induction Machines for Traction in Electric and Hybrid Electric Vehicles JF - World Electric Vehicle Journal N2 - An electric traction machine for an electric or a hybrid electric vehicle is usually designed for a specific operating point or cycle. For such an operating point or cycle, the masses and the cooling circuit of the electric machine determine the time dependent temperature distribution within the machine. For a specific load cycle, the thermal simulation of the machine can reveal possible mass and size reductions for a given insulation class of the machine. In addition, such simulations allow the comparison of various cooling concepts. In the machine design process, the first step is a conventional electromagnetic machine design. From the geometric data of this design and the material properties, the parameters of a thermal equivalent circuit can be derived. The differential and algebraic equations of the thermal equivalent circuit are solved by a simulation tool to predict the temperatures of the critical parts in the electric machine. A thermal equivalent circuit is accurate enough to predict the thermal behavior of the critical parts in the electric machine, and yet not too complex, to obtain simulation results with moderate numerical effort. This enables an iterative design process to optimize the drive. KW - Induction Motor KW - Electric Drive KW - Modeling KW - Simulation KW - Thermal Management Y1 - 2007 U6 - https://doi.org/10.3390/wevj1010190 SN - 2032-6653 VL - 1 IS - 1 SP - 190 EP - 196 PB - MDPI ER - TY - JOUR A1 - Reschke, Johannes A1 - Neumann, Cornelius A1 - Berlitz, Stephan T1 - Personalised neural networks for a driver intention prediction: communication as enabler for automated driving JF - Advanced Optical Technologies N2 - In everyday traffic, pedestrians rely on informal communication with other road users. In case of auto� mated vehicles, this communication can be replaced by light signals, which need to be learned beforehand. Prior to an extensive introduction of automated vehicles, a learning phase for these light signals can be set up in manual driving with help of a driver intention prediction. Therefore, a three-staged algorithm consisting of a neural network, a random forest and a conditional stage, is implemented. Using this algorithm, a true-positive rate (TPR) of 94.0% for a 5.0% false-positive rate (FPR) can be achieved. To improve this process, a personalization pro� cedure is implemented, using driver-specific behaviours, resulting in TPRs ranging from 91.5 to 96.6% for a FPR of 5.0%. Transfer learning of neural networks improves the prediction accuracy of almost all drivers. In order to introduce the implemented algorithm in today’s traffic, especially the FPR has to be improved considerably. KW - automotive lighting KW - learning signals KW - recurrent neural networks KW - time sequence processing KW - vehicle-pedestrian-communication Y1 - 2020 U6 - https://doi.org/10.1515/aot-2020-0035 VL - 9 IS - 6 SP - 357 EP - 364 PB - De Gruyter ER - TY - INPR A1 - Linz, Tilo A1 - Mottok, Jürgen T1 - Application of Causal Models in Scenario-based Testing N2 - This paper presents a new methodology for scenario-based testing of automated driving functions in the context of ISO 21448 (safety of the target function). By using structural causal models (SCMs), the evaluation process of highly automated vehicle systems is to be improved, thus increasing their safety and reliability. Using SCMs, the presented methodology systematically analyzes causal relationships between various risk factors of the investigated system and its operating environment and automatically identifies potential parameter combinations that influence system safety. This approach makes it possible to safeguard automated driving functions, such as an emergency brake assistant, by determining foreseeable risks and providing them as test parameters for relevant scenarios. The HolmeS3 approach combines expert knowledge with probabilistic data analysis to develop robust causal models that can be validated through both simulation and real-world testing. The use of causal inference enables the generation of critical test cases, known as "edge and corner cases", which are essential for testing vehicle systems under investigation. This focused testing approach helps to limit the test case explosion that occurs with conventional approaches by specifically identifying highly relevant parameter combinations that potentially (negatively) influence system performance. The methodology presented, which was developed as part of the HolmeS3 R&D project, offers transparency, comparability, explainability and traceability in the modeling and testing processes. It supports compliance with the ISO 21448 standard and lays the foundation for the causality-driven development of safe and reliable automotive technology. The project's tools and methods can be applied beyond the automotive sector to all cyber-physical systems that require rigorous safety validation. Y1 - 2024 U6 - https://doi.org/10.13140/RG.2.2.34160.06402 ER - TY - CHAP A1 - Frauenschläger, Tobias A1 - Mottok, Jürgen T1 - Problems and New Approaches for Crypto-Agility in Operational Technology T2 - 12th European Congress Embedded Real Time Systems (ERTS 2024), 11-12 June 2024, Toulouse, France N2 - In recent years, cybersecurity has also become relevant for Operational Technology (OT). Critical systems like industrial automation systems or transportation systems are faced with new threats, and therefore require the implementation of thorough security measures. Regulations further mandate the deployment and regular verification of these security measures. However, OT systems differ from well-known systems of classic Information Technology (IT), such as mission times spanning decades, infrequent updates only during on-site maintenance, or diverse devices with varying support for security measures. The growing field of crypto-agility examines approaches to integrate security measures in an agile and flexible way, making updates easier and, therefore, encouraging a more frequent deployment of them. This paper contributes to this research field in the context of secure communication in two ways. We first examine the current state of crypto-agility by providing an overview of existing measures for OT systems. Then, we propose a new architecture concept with different deployment approaches to integrate security measures in a crypto-agile way. Based on a security library with a generic interface and a flexible proxy application, our architecture is capable of securing both new OT systems and existing ones via retrofit. Y1 - 2024 UR - https://www.researchgate.net/publication/383709526_Problems_and_New_Approaches_for_Crypto-Agility_in_Operational_Technology ER - TY - CHAP A1 - Schwind, Philipp A1 - Frauenschläger, Tobias A1 - Mottok, Jürgen T1 - Implementation of a Bump-in-the-Wire Security Gateway T2 - Proceedings of the 12th Prague Embedded Systems Workshop, June 27 - 29, 2024, Horoměřice, Czech Republic N2 - In the face of escalating cyber threats, the integration of Operational Technology (OT) with Information Technology (IT) systems presents heightened vulnerabilities to critical infrastructures. This paper focuses on the need for cybersecurity, showcasing the design and implementation of a security gateway to achieve bump-in-the-wire security between two units to be protected (assets). For that, each asset is assigned one security module that safeguards its communication paths. To ease bump-in-the-wire capability, the communication between the asset and the security-gateway must be stateless and operate on OSI layer 2. This is necessary to safeguard the whole communication bandwidth, regardless of the used protocols. For this objective, Linux-based packet sockets are used. An encrypted tunnel is established between two security gateways using the Datagram Transport Layer Security (DTLS) protocol. The results show that the implemented solution is capable of securing the asset’s network traffic without the need of any modifications. Y1 - 2024 UR - https://pesw.fit.cvut.cz/2024/PESW_2024.pdf SN - 978-80-01-07303-2 SP - 26 EP - 35 ER - TY - JOUR A1 - Tremmel, Florian A1 - Nagler, Oliver A1 - Kutter, Christoph A1 - Holmer, Rainer T1 - Double-Beam Cantilever Probe for Crack Probability Analysis of Multilayer Substrates During Wafer Probing JF - IEEE Sensors Journal N2 - During wafer testing, small probes are contacting pads on the wafer surface to check the chip functionality and identify faulty dies. To prevent damaging structures underneath, a mechanical load limit needs to be defined. This is done by intentionally overstressing the pads and searching for cracks that appear. A customized test bench with a patented sensor-indenter (SI) system is currently used to perform the contact cycles and identify crack formations in real time using the generated acoustic emissions (AEs). This method is faster and more accurate compared with previous optical detection methods. This article presents an improved version of the SI system usable in a wafer prober, featuring a double-beam cantilever beam with an exchangeable indenter tip. This leads to measurement conditions closer to productive wafer testing, enabling more accurate load limit definitions. The cantilever beam contains a strain gauge Wheatstone bridge for contact force measurement and a piezoelectric sensor element for AE signal detection. Amplifier circuits are designed for both sensors, and a data acquisition (DAQ) system is developed. A prototype of the sensor cantilever combination (SCC) is shown together with simulated and experimental results. The accuracy of the force sensor ( ±0.5 → ±1.3 mN) and the signal-to-noise ratios (SNRs) of the AE signals ( 29.1 → 21 dB) show only a small decrease compared with the previous SI system. A crack probability analysis of a test specimen confirms the usability of the SCC, as AE crack signals are detected at a similar mechanical load with both sensor setups. KW - Acoustic emission (AE) testing KW - double-beam cantilever load senso KW - fracture load limit KW - operational amplifier circuit Y1 - 2024 U6 - https://doi.org/10.1109/JSEN.2024.3486355 VL - 24 IS - 24 SP - 40295 EP - 40304 PB - IEEE ER - TY - JOUR A1 - Keiner, Dominik A1 - Walter, Lukas A1 - Bogdanov, Dmitrii A1 - Peters, Ian Marius A1 - Breyer, Christian T1 - Assessing the impact of bifacial solar photovoltaics on future power systems based on capacity-density-optimised power plant yield modelling JF - Solar Energy N2 - Bifacial solar photovoltaic (PV) technology is currently taking over the solar PV module market, exceeding a 90% share in 2025. This important technology must be included in energy system modelling. This study provides a method for calculating the yield of monofacial and bifacial power plants in fixed-tilted, single-axis tracking, and east-west facing vertical setup. A novel method is introduced to maximise the capacity density of solar PV power plants without the need for detailed land cost for the most efficient use of the occupied area. The results indicate a 15-20% yield gain from single-axis tracking compared to fixed-tilted power plants, and a limited bifacial gain of up to 10% for most areas of the world. Higher bifacial gains are sporadically possible in specific conditions. Fixed-tilted systems show higher bifacial gains. Optimising tilt angles and row pitch would allow for 147 MW/ km2 capacity density today, though on average 70-110 MW/km2 can be achieved for 20.2% module efficiency. The impact on the power system, studied in a free cost optimisation scenario and forcing vertical bifacial PV scenario, implying agrivoltaics, is not significant with a +/- 10% change in total solar PV capacity, change in installed wind power of on average-10%, increase of installed battery capacity of on average 5%, and an on average changed levelised cost of electricity of-2% globally. Bifacial solar PV technology has been found to be beneficial but no game changer for future power systems; system improvements are widely possible underlining the important role of this technology. KW - Bifacial KW - Capacity density KW - Energy system modelling KW - Monofacial KW - photovoltaics KW - Power plant Y1 - 2025 U6 - https://doi.org/10.1016/j.solener.2025.113543 VL - 295 PB - Elsevier ER - TY - JOUR A1 - Doepfert, Markus A1 - Candas, Soner A1 - Kraus, Hermann A1 - Tzscheutschler, Peter A1 - Hamacher, Thomas T1 - Assessing the techno-economic benefits of LEMs for different grid topologies and prosumer shares JF - iScience N2 - The shift toward decentralized and renewable energy sources has introduced significant challenges to traditional power systems, necessitating innovative market designs. Local energy markets present a viable solution for integrating distributed energy resources such as photovoltaic systems, electric vehicles, and heat pumps. This study investigates the techno-economic implications of local energy markets compared to conventional market designs, focusing on their impact on average energy prices and operational peak power. Through comprehensive simulations across various grid topologies with varying penetration levels of the distributed energy resources, totaling 400 simulation setups, we demonstrate that local energy markets can enhance economic efficiency and grid stability with 99% of the scenarios boasting lower average energy prices and 80% lower operational peak power levels. The findings suggest that local energy markets can play a role in the future energy system, provided that additional infrastructure, management costs, and bureaucratic complexity are kept to a minimum. Y1 - 2025 U6 - https://doi.org/10.1016/j.isci.2025.112493 VL - 28 IS - 6 PB - Elsevier - Cell Press ER - TY - JOUR A1 - Prem, Nina A1 - Chavez Vega, Jhohan Harvey A1 - Böhm, Valter A1 - Sindersberger, Dirk A1 - Monkman, Gareth J. A1 - Zimmermann, Klaus T1 - Properties of Polydimethylsiloxane and Magnetoactive Polymers with Electroconductive Particles JF - Macromolecular Chemistry and Physics N2 - Magnetoactive polymers are intelligent materials whose mechanical and electrical characteristics are reversibly influenced by external magnetic stimuli. They consist of a highly elastic polymer matrix in which magnetically soft and/or hard particles are distributed by means of special fabrication processes. In addition to ferromagnetic particles such as carbonyl iron powder, electrically conductive particles may also be embedded into the polymer matrix. After characterizing a range of compounds, this work focuses on a comparison of the electrical properties and the suitability of various materials for applications, with particular emphasis on integration into 3D and 6D printing processes. 6D printing is based on the selective positioning of particles in a 3D polymer matrix with a further three degrees of freedom for a graduated dispersion of the particles at certain points and in desired directions. The aim is therefore to ensure that the polymers containing electroconductive tracks have the best possible electrical properties, that is, low resistivity but are still capable of being printed. A comparison between the traditionally used compounds containing graphite and carbon black is made for the first time. This latter is found to be greatly superior both in terms of electrical conductivity and applicability to 3D printing and 6D printing. KW - 3D printing KW - 6D printing KW - carbon black KW - composites KW - electroconductive particles KW - graphite KW - magnetoactive polymers KW - polydimethylsiloxane KW - STRAIN, *MRU Y1 - 2018 U6 - https://doi.org/10.1002/macp.201800222 VL - 219 IS - 18 PB - Wiley ER - TY - JOUR A1 - Thema, Martin A1 - Bauer, Franz A1 - Sterner, Michael T1 - Power-to-Gas: Electrolysis and methanation status review JF - Renewable and Sustainable Energy Reviews N2 - This review gives a worldwide overview on Power-to-Gas projects producing hydrogen or renewable substitute natural gas focusing projects in central Europe. It deepens and completes the content of previous reviews by including hitherto unreviewed projects and by combining project names with details such as plant location. It is based on data from 153 completed, recent and planned projects since 1988 which were evaluated with regards to plant allocation, installed power development, plant size, shares and amounts of hydrogen or substitute natural gas producing examinations and product utilization phases. Cost development for electrolysis and carbon dioxide methanation was analyzed and a projection until 2030 is given with an outlook to 2050. The results show substantial cost reductions for electrolysis as well as for methanation during the recent years and a further price decline to less than 500 euro per kilowatt electric power input for both technologies until 2050 is estimated if cost projection follows the current trend. Most of the projects examined are located in Germany, Denmark, the United States of America and Canada. Following an exponential global trend to increase installed power, today's Power-to-Gas applications are operated at about 39 megawatt. Hydrogen and substitute natural gas were investigated on equal terms concerning the number of projects. KW - Biological CO2-Methanation KW - Chemical CO2-Methanation KW - Cost-development KW - Electrolysis KW - Power-to-Gas Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-26238 N1 - Corresponding author: Martin Thema VL - 112 IS - 7 SP - 775 EP - 787 PB - Elsevier ER - TY - JOUR A1 - Sterner, Michael A1 - Hofrichter, Andreas A1 - Meisinger, Alexander A1 - Bauer, Franz A1 - Pinkwart, Karsten A1 - Maletzko, Annabelle A1 - Dittmar, Felix A1 - Cremers, Carsten T1 - 19 Import options for green hydrogen and derivatives - An overview of efficiencies and technology readiness levels JF - International Journal of Hydrogen Energy N2 - The import of hydrogen and derivatives forms part of many national strategies and is fundamental to achieving climate protection targets. This paper provides an overview and technical comparison of import pathways for hydrogen and derivatives in terms of efficiency, technological maturity and development and construction times with a focus on the period up to 2030. The import of hydrogen via pipeline has the highest system efficiency at 57-67 % and the highest technological maturity with a technology readiness level (TRL) of 8-9. The import of ammonia and methanol via ship and of SNG via pipeline shows efficiencies in the range of 39-64 % and a technological maturity of TRL 7 to 9 when using point sources. Liquid hydrogen, LOHC and Fischer-Tropsch products have the lowest efficiency and TRL in comparison. The use of direct air capture (DAC) reduces efficiency and TRL considerably. Reconversion of the derivatives to hydrogen is also associated with high losses and is not achievable for all technologies on an industrial scale up to 2030. In the short to medium term, import routes for derivatives that can utilise existing infrastructures and mature technologies are the most promising for imports. In the long term, the most promising option is hydrogen via pipelines. KW - Hydrogen KW - Derivatives KW - Power-to-X KW - Efficiency KW - TRL KW - Construction time KW - Technical assessment KW - Import KW - Hydrogen strategy KW - Energy system modelling Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-77756 SN - 0360-3199 N1 - Corresponding author der OTH Regensburg: Michael Sterner VL - 90 SP - 1112 EP - 1127 PB - Elsevier ER - TY - JOUR A1 - Kovalev, Alexander A1 - Belyaeva, Inna A. A1 - von Hofen, Christian A1 - Gorb, Stanislav A1 - Shamonin (Chamonine), Mikhail T1 - Magnetically Switchable Adhesion and Friction of Soft Magnetoactive Elastomers JF - Advanced Engineering Materials N2 - Herein, the effect of an applied moderate (~240 mT) magnetic field on the work of adhesion (WoA) of mechanically soft (the shear modulus ~10 kPa) magnetoactive elastomer (MAE) samples with two different mass fractions (70 and 80 wt%) of carbonyl iron powder (CIP) is concerned. The unfilled elastomer sample is used for comparison. Due to some sedimentation of filling particles, the concentration of inclusions in thin (~10 μm) subsurface layers is different. It is shown that the WoA increases (up to 1.8-fold) on the particle-enriched side (PES) in the magnetic field and its value is higher for higher filler concentration. On the particle-depleted side (PDS), WoA does not depend on particle concentration and on the magnetic field. Adhesion and friction are coupled in MAEs. No statistically significant difference in the friction coefficient, determined from the extended Amontons´ law, depending on sample side, CIP concentration, or presence of magnetic field is found. However, the PDS in the magnetic field demonstrates significantly higher critical shear stress compared to that for the PES or PDS in the absence of magnetic field. Correlations between different surface properties are discussed. Obtained results are useful for the development of magnetically controllable soft robots. Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-45283 N1 - Corresponding authors: Stanislav Gorb und Mikhail Shamonin VL - 24 IS - 10 SP - 1 EP - 8 PB - WILEY-VCH ER - TY - INPR A1 - Kroiß, Lukas A1 - Reschke, Johannes T1 - Deepfake Detection of Face Images based on a Convolutional Neural Network N2 - Fake News and especially deepfakes (generated, non-real image or video content) have become a serious topic over the last years. With the emergence of machine learning algorithms it is now easier than ever before to generate such fake content, even for private persons. This issue of generated fake images is especially critical in the context of politics and public figures. We want to address this conflict by building a model based on a Convolutions Neural Network in order to detect such generated and fake images showing human portraits. As a basis, we use a pre-trained ResNet-50 model due to its effectiveness in terms of classifying images. We then adopted the base model to our task of classifying a single image as authentic/real or fake by adding an fully connected output layer containing a single neuron indicating the authenticity of an image. We applied fine tuning and transfer learning to develop the model and improve its parameters. For the training process we collected the image data set ’Diverse Face Fake Dataset’ containing a wide range of different image manipulation methods and also diversity in terms of faces visible on the images. With our final model we reached the following outstanding performance metrics: precision = 0.98, recall 0.96, F1-Score = 0.97 and an area-under-curve = 0.99. KW - ResNet-50 KW - Transfer Learning KW - Binary Classification KW - diverse fake face dataset KW - Probability Density Function Y1 - 2025 U6 - https://doi.org/10.48550/arXiv.2503.11389 PB - arxiv ER - TY - CHAP A1 - Horn, Luca A1 - Frauenschläger, Tobias A1 - Mottok, Jürgen T1 - Integration and Evaluation of Different FPGA based Hardware Accelerators for the AES Algorithm in the TLS Protocol to be Used in Critical Automation Systems T2 - 4. Symposium Elektronik und Systemintegration, Tagungsband: Symposium am 17. April 2024 Hochschule Landshut N2 - This thesis addresses the challenges of hardware-assisted cryptography in the context of automation systems in critical infrastructures. While hardware accelerators enhance cryptographic calculations in both performance and security, their permanence poses issues in adapting to evolving security concerns. To overcome this problem, we integrated and evaluated a hardware accelerator for the AES algorithm on an FPGA within a TLS application, comparing its performance with other accelerators. Employing a hybrid FPGA-CPU processor system, this setup achieves over 800 Mbit/s data rates, showcasing a more than 27 times acceleration in TLS transmissions compared to purely software-based solutions. The FPGA's flexibility and upgradability therefore make it an ideal platform for critical infrastructure, ensuring longevity and superior acceleration in TLS data transfers. Y1 - 2024 UR - https://www.haw-landshut.de/static/ITZ/Bilder/Cluster_MST/ESI_Symposium/ESI_2024/Tagungsband/1B2_Frauenschlaeger_OTH-R_TB-ESI2024_s18-27.pdf SN - 978-3-9818439-9-6 SP - 18 EP - 27 PB - Hochschule Landshut CY - Landshut ER - TY - CHAP A1 - Hauser, Florian A1 - Grabinger, Lisa A1 - Mottok, Jürgen A1 - Gruber, Hans T1 - Visual Expertise in Code Reviews: Using Holistic Models of Image Perception to Analyze and Interpret Eye Movements T2 - ETRA '23: 2023 Symposium on Eye Tracking Research and Applications, Tubingen Germany 30 May 2023- 2 June 2023 N2 - This study uses holistic models of image perception to analyze and interpret eye movements during a code review. 23 participants (15 novices and 8 experts) take part in the experiment. The subjects’ task is to review six short code examples in C programming language and identify possible errors. During the experiment, their eye movements are recorded by an SMI 250 REDmobile. Additional data is collected through questionnaires and retrospective interviews. The results implicate that holistic models of image perception provide a suitable theoretical background for the analysis and interpretation of eye movements during code reviews. The assumptions of these models are particularly evident for expert programmers. Their approach can be divided into different phases with characteristic eye movement patterns. It is best described as switching between scans of the code example (global viewing) and the detailed examination of errors (focal viewing). Y1 - 2023 U6 - https://doi.org/10.1145/3588015.3589189 SP - 1 EP - 7 PB - ACM ER - TY - CHAP A1 - Reindl, Andrea A1 - Wetzel, Daniel A1 - Niemetz, Michael A1 - Meier, Hans T1 - Leader Election in a Distributed CAN-Based Multi-Microcontroller System T2 - 2023 3rd International Conference on Electrical, Computer, Communications and Mechatronics Engineering (ICECCME), 19-21 July 2023, Tenerife, Canary Islands, Spain N2 - In a distributed system, functionally equivalent nodes work together to form a system with improved availability, reliability and fault tolerance. Thereby, the purpose is to achieve a common control objective. As multiple components cooperate to accomplish tasks, coordination between them is required. Electing a node as the temporary leader can be a possible solution to perform coordination. This work presents a self-stabilizing algorithm for the election of a leader in dynamically reconfigurable bus topology-based broadcast systems with a message and time complexity of O(1). The election is performed dynamically, i.e., not only when the leader node fails, and is criterion-based. The criterion used is a performance related value which evaluates the properties of the node regarding the ability to perform the tasks of the leader. The increased demands on the leader are taken into account and a re-election is started when the criterion value drops below a predefined level. The goal here is to distribute the load more evenly and to reduce the probability of failure due to overload of individual nodes. For improved system availability and reduced fault rates, a management level consisting of leader, assistant and co-assistant is introduced. This reduces the number of required messages and the duration in case of non-initial election. For further reduction of required messages to uniquely determine a leader, the CAN protocol is exploited. The proposed algorithm selects a node with an improved failure rate and a reduced message and hence time complexity while satisfying the safety and termination constraints. The operation of the algorithm is validated using a hardware test setup. KW - broadcast communication KW - computational complexity KW - controller area networks KW - coordination KW - decentralized applications KW - distributed systems KW - failure analysis KW - Fault tolerance KW - fault tolerant computing KW - Fault tolerant systems KW - Hardware KW - Heuristic algorithms KW - Leader election KW - load balancing KW - Mechatronics KW - message complexity KW - microcontrollers KW - performance related election KW - probability KW - Protocols KW - self-stabilization KW - telecommunication network topology KW - Voting Y1 - 2023 SN - 979-8-3503-2297-2 U6 - https://doi.org/10.1109/ICECCME57830.2023.10252250 SP - 1 EP - 8 PB - IEEE CY - Piscataway, NJ, USA ER - TY - CHAP A1 - Reindl, Andrea A1 - Lausser, Florian A1 - Eriksson, Lars A1 - Park, Sangyoung A1 - Niemetz, Michael A1 - Meier, Hans ED - Pinker, Jiří T1 - Control Oriented Mathematical Modeling of a Bidirectional DC-DC Converter - Part 1: Buck Mode T2 - 28th International Conference on Applied Electronics (AE) 2023, Pilsen, 6-7 September 2023 N2 - Parallel connection of different batteries equipped with bidirectional DC-DC converters offers an increase of the total storage capacity, the provision of higher currents and an improvement of reliability and system availability. To share the load current among the DC-DC converters while maintaining the safe operating range of the batteries, appropriate controllers are needed. The basis for the design of these control approaches requires knowledge of both the static and dynamic characteristics of the DC-DC converter used. In this paper, the small signal analysis of a DC-DC converter in buck mode is shown using the circuit averaging technique. The paper gives an overview of all required transfer functions:. The control and line to output transfer functions for CCM and DCM relevant for average current mode control as well as for voltage control are derived and their poles and zeros are determined. This provides the basis for stability consideration, analysis of the overall control structure and controller design. KW - Analytical models KW - Average modeling KW - Batteries KW - bidirectional dc-dc converter KW - buck mode KW - circuit-averaging technique KW - continuous conduction mode KW - DC-DC power converters KW - derivation of transfer functions KW - discontinuous conduction mode KW - half-bridge KW - Mathematical models KW - Reliability KW - Signal analysis KW - small signal analysis KW - Stability analysis Y1 - 2023 SN - 979-8-3503-3554-5 U6 - https://doi.org/10.1109/AE58099.2023.10274168 SP - 1 EP - 7 PB - University of West Bohemia CY - Pilsen ER - TY - JOUR A1 - Lohmeyer, Manfred A1 - Shamonin (Chamonine), Mikhail A1 - Hertel, Peter T1 - Integrated optical circulator based on radiatively coupled magneto-optic waveguides JF - Optical Engineering N2 - In a three-guide coupler with multimode central waveguide, more than two modes of the entire structure participate in the coupling between the outer waveguides. Using a three-mode approximation we found simple conditions for complete power transfer between the outer waveguides: the device length has to match certain multiples of the con- ventionally defined coupling length. The specific form of the relevant modes allows us to design a magneto-optic isolator or circulator with significantly reduced device length (as compared to the conventional nonreciprocal coupler). The performance of the proposed devices is simulated by propagating-mode calculations. Estimates for admissible fabrication tolerances for the layer thicknesses are presented. KW - integrated optics KW - magneto-optic circulator KW - magneto-optic isolator KW - radiatively coupled waveguides KW - three-guide coupler Y1 - 1997 U6 - https://doi.org/10.1117/1.601255 VL - 36 IS - 3 SP - 889 EP - 895 PB - SPIE ER - TY - JOUR A1 - Pozzobon, Enrico A1 - Weiß, Nils A1 - Mottok, Jürgen A1 - Matoušek, Václav T1 - An evolutionary fault injection settings search algorithm for attacks on safe and secure embedded systems JF - Neural Network World (NNW) Y1 - 2023 U6 - https://doi.org/10.14311/NNW.2023.33.020 VL - 33 IS - 5 SP - 357 EP - 374 PB - Czech Technical University in Prague ER - TY - CHAP A1 - Füreder, Lukas A1 - Mottok, Jürgen T1 - Assessment of a MACsec-based Security System for Use in Critical Infrastructure Communication T2 - Proceedings of the 12th Prague Embedded Systems Workshop, June 27 - 29, 2024, Horoměřice, Czech Republic N2 - This paper investigates the integration of Media Access Control Security (MACsec) into the communication of critical infrastructure, specifically within power grid applications, such as Substation Automation Systems (SAS) using the IEC 61850 standard. Building on the principles of both standards, this study aims to determine if MACsec can meet the security and performance requirements set by IEC 62351 for power system communications. Furthermore, a test environment containing a number of Intelligent Electronic Devices (IEDs) supporting communication compliant to all IEC 61850 message types is established to evaluate this integration. The results of the measurements executed in this environment indicate that MACsec could secure all types of messages, such as Manufacturing Message Specification (MMS), Sampled-Value (SV) and Generic Object Oriented Substation Events (GOOSE), within the required time periods without significant delays. Even with additional encryption activated in the cipher suite, the resulting transmission times are well below the required times. This suggests that MACsec can enhance the security goals for industrial communication by providing confidentiality in addition to the already mandated assurance of authenticity and integrity to all messages without compromising performance. Only the requirement for end-to-end security cannot be met by MACsec in this configuration, as the security system re-encrypts with every hop of the transmission. For this reason, we propose a hybrid approach of Transport Layer Security (TLS) and MACsec as part of future work. KW - MACsec KW - IEC61850 KW - IEC62351 KW - GOOSE KW - Secure Communication Y1 - 2024 UR - https://pesw.fit.cvut.cz/2024/PESW_2024.pdf SN - 978-80-01-07303-2 SP - 51 EP - 59 ER - TY - CHAP A1 - Bittner, Dominik A1 - Hendricks, Ricky-Ricardo A1 - Horn, Luca A1 - Mottok, Jürgen T1 - In-depth Benchmarking of Transfer Learning Techniques for Improved Bottle Recognition T2 - 2023 IEEE 13th International Conference on Pattern Recognition Systems (ICPRS), Guayaquil, Ecuador, 04-07 July 2023 N2 - An immense diversity in bottle types requires high accuracy during sorting for recycling purposes by breweries. This extremely complex and time-consuming procedure can result in enormous additional costs for them. This paper presents transfer learning-based algorithms for classifying beer bottle brands using camera images, applicable in individual sorting solutions for different use cases. The problem is tackled using customised EfficientNet, InceptionResNet and VGG models along with an augmented dataset. In addition, a detailed analysis of different model and parameter combinations is performed, enabling tailor-made technologies for specific conditions and resource limitations. In accompanying validations and subsequent tests, a test accuracy of 100% in the recognition of beer brands could be achieved, proving the proposed method fully contributes to the solution of the problem. KW - Analytical models KW - Costs KW - Transfer learning KW - Benchmark testing KW - Cameras KW - Pattern recognition KW - Recycling Y1 - 2023 SN - 979-8-3503-3337-4 U6 - https://doi.org/10.1109/ICPRS58416.2023.10178995 SP - 1 EP - 6 PB - IEEE ER - TY - CHAP A1 - Fuhrmann, Thomas A1 - Niemetz, Michael T1 - Analysis and Improvement of Engineering Exams Toward Competence Orientation by Using an AI Chatbot T2 - Towards a Hybrid, Flexible and Socially Engaged Higher Education: Proceedings of the 26th International Conference on Interactive Collaborative Learning (ICL2023), Volume 1 N2 - ChatGPT is currently one of the most advanced general chatbots. This development leads to diverse challenges in higher education, like new forms of teaching and learning, additional exam methods, new possibilities for plagiarism, and many more topics. On the other side with the development of advanced AI tools, pure knowledge will be less and less important, and demands from industry will change toward graduates with higher competencies. Education has therefore to be changed from knowledge-centered toward competence centered. The goal of this article is to use ChatGPT for analyzing and improving the competence orientation of exams in engineering education. The authors use ChatGPT to analyze exams from different engineering subjects to evaluate the performance of this chatbot and draw conclusions about the competence orientation of the tested exams. The obtained information is used to develop ideas for increasing the competence orientation of exams. From this analysis, it is visible that ChatGPT gives good performance mainly where knowledge is tested. It has, however, much more problems with transfer questions or tasks where students need creativity or complex insights for finding new solutions. Based on this result, exams and also lectures can be optimized toward competence orientation. KW - Engineering education KW - Competence orientation KW - Exam analysis KW - AI chatbot KW - ChatGPT Y1 - 2024 SN - 9783031519789 U6 - https://doi.org/10.1007/978-3-031-51979-6_42 SN - 2367-3370 SP - 403 EP - 411 PB - Springer Nature CY - Cham ER - TY - JOUR A1 - Johnson, Ebin M. A1 - Anwer, Shakil A1 - Xu, Yongchao A1 - Fuhrmann, Thomas A1 - Mandl, Roland T1 - Contactless Low-Cost Position Sensor using a D-Shaped Polymer Optical Fiber JF - IEEE Sensors Journal N2 - This article describes a contactless fiber-optic position sensor. It comprises a Polymer Optical Fiber that is grinded to form a D-shaped cross-section with an exposed fiber core. This sensor has two photodiodes at both fiber ends to measure the emitted light intensity. Light is coupled using a red LED at the side face into the exposed core of the fiber at a defined position. The position of the LED at the length of the fiber is measured by calculating the optical power quotient measured by both photodiodes. To test this sensor, Polymer Optical Fibers with different side surface roughness are produced and qualified. Measurements show that the optical power quotient is reproducible and nearly linear over the length of the fiber. It is also seen that the fiber attenuation increases when grinding the fiber side-face with rougher sandpaper. Position measurements show an absolute position error of this sensor in the range of a few millimeters. Microscope images show surface defects along the polished side face of the fiber that are expected to lead to a nonuniform attenuation along the fiber and cause the position errors. Overall, it is proven that this sensor principle works as a contactless low-cost position sensor for short distances with an absolute position standard deviation error lower than 1 mm. KW - Optical fibers KW - Optical fiber sensors KW - Sensors KW - Photodiodes KW - Optical surface waves KW - Surface roughness KW - Rough surfaces KW - Fiber-optic sensor KW - Position measurement KW - Polymer Optical Fiber Y1 - 2024 U6 - https://doi.org/10.1109/JSEN.2023.3348127 PB - IEEE ER - TY - CHAP A1 - Haumer, Anton T1 - Modeling and Control Design of an Educational Magnetic Levitation System T2 - Proceedings of the 15th International Modelica Conference 2023, Aachen, October 9-11 N2 - A magnetic levitation system is a perfect educational example of a nonlinear unstable system. Only with suitable control, a small permanent magnet can be held floating stable below a coil. After modeling and simulation of the system, control of the system can be developed. At the end, the control algorithm can be coded on a microcontroller, connected to a pilot plant. KW - mechatronics KW - magnetic levitation KW - time-discrete control KW - functional mockup interface Y1 - 2023 U6 - https://doi.org/10.3384/ecp204763 SN - 1650-3686 PB - Linköping University Electronic Press ER - TY - JOUR A1 - Belyaeva, Inna A. A1 - Kramarenko, Elena Yu A1 - Stepanov, Gennady V. A1 - Sorokin, Vladislav V. A1 - Stadler, Dominik A1 - Shamonin (Chamonine), Mikhail T1 - Transient magnetorheological response of magnetoactive elastomers to step and pyramid excitations JF - SOFT MATTER N2 - Transient rheological response of magnetoactive elastomers is experimentally studied using dynamic torsion at a fixed oscillation frequency in temporally stepwise changing magnetic fields and oscillation amplitudes. For step magnetic-field excitations, at least three exponential functions are required to reasonably describe the time behavior of the storage shear modulus over long time scales (>10(3) s). The deduced characteristic time constants of the corresponding rearrangement processes of the filler network differ approximately by one order of magnitude: tau(1) less than or similar to 10(1) s, tau(2) similar to 10(2) s, and tau(3) similar to 10(3) s. The sudden imposition of the external magnetic field activates a very fast rearrangement process with the characteristic time under 10 s, which cannot be determined more precisely due to the measurement conditions. Even more peculiar transient behavior has been observed during pyramid excitations, when either the external magnetic field was first stepwise increased and then decreased in a staircase manner at a fixed strain amplitude gamma or the strain amplitude gamma was first stepwise increased and then decreased in a staircase manner at a fixed magnetic field. In particular, the so-called "cross-over effect'' has been identified in both dynamical loading programs. This cross-over effect seems to be promoted by the application of the external magnetic field. The experimental results are discussed in the context of the specific rearrangement of the magnetic filler network under the simultaneous action of the external magnetic field and shear deformation. Striking similarities of the observed phenomena to the structural relaxation processes in glassy materials and to the jamming transition of granular materials are pointed out. The obtained results are important for fundamental understanding of material behavior in magnetic fields as well as for the development of devices on the basis of magnetoactive elastomeric materials. KW - AMPLITUDE KW - BEHAVIOR KW - DEPENDENCE KW - FLUID KW - HOMOGENEOUS MAGNETIC-FIELD KW - NORMAL FORCE KW - OSCILLATORY SHEAR KW - TIME KW - VISCOELASTIC PROPERTIES Y1 - 2016 U6 - https://doi.org/10.1039/c5sm02690c VL - 12 IS - 11 SP - 2901 EP - 2913 PB - ROYAL SOC CHEMISTRY ER - TY - JOUR A1 - Belyaeva, Inna A. A1 - Kramarenko, Elena Yu A1 - Shamonin (Chamonine), Mikhail T1 - Magnetodielectric effect in magnetoactive elastomers: Transient response and hysteresis JF - POLYMER N2 - Magnetodielectric properties of magnetoactive elastomers comprising micrometer-sized iron particles dispersed in compliant elastomer matrices are experimentally studied in stepwise time-varying dc magnetic fields. It is found that imposition of magnetic field significantly increases both the effective lossless permittivity of these composite materials as well as their effective conductivity. These magnetodielectric effects are more pronounced for larger concentrations of soft-magnetic filler particles and softer elastomer matrices. The largest observed relative change of the effective dielectric constant in the maximum magnetic field of 0.57 T is of the order of 1000%. The largest observed absolute change of the loss tangent is approximately 0.8. The transient response of the magnetodielectric effect to a step magnetic-field excitation can be rather complex. It changes from a simple monotonic growth with time for small magnetic-field steps (<0.1 T) to a non-monotonic behavior with a significant rapidly appearing overshoot for large magnetic-field steps (>0.3 T). The settling time to the magnetic-field step excitation can reach roughly 1000 s and it depends on the applied magnetic field and sample composition. There is also significant hysteresis of the magnetodielectric effect on the externally applied magnetic field. These findings are attributed to the rearrangement of ferromagnetic filler particles in external magnetic fields. The results will be useful for understanding and predicting the transient behavior of magnetoactive elastomers in applications where the control magnetic field is time dependent. (C) 2017 Elsevier Ltd. All rights reserved. KW - BEHAVIOR KW - composites KW - DIELECTRIC-PROPERTIES KW - hysteresis KW - MAGNETIC-FIELD KW - magnetoactive elastomer KW - magnetodielectric effect KW - Magnetorhelogical elastomer KW - MELT STATE KW - MICROSTRUCTURE KW - POLYMER DEGRADATION KW - PROGRESS KW - Smart material KW - THERMOOXIDATIVE DEGRADATION KW - TIME-RESOLVED RHEOLOGY KW - Transient response Y1 - 2017 U6 - https://doi.org/10.1016/j.polymer.2017.08.056 VL - 127 SP - 119 EP - 128 PB - ELSEVIER ER - TY - CHAP A1 - Sterner, Michael A1 - Bauer, Franz A1 - Crotogino, Fritz A1 - Eckert, Fabian A1 - von Olshausen, Christian A1 - Teichmann, Daniel A1 - Thema, Martin ED - Sterner, Michael ED - Stadler, Ingo T1 - Chemical Energy Storage T2 - Handbook of Energy Storage N2 - Purely electrical energy storage technologies are very efficient, however they are also very expensive and have the smallest capacities. Electrochemical-energy storage reaches higher capacities at smaller costs, but at the expense of efficiency. This pattern continues in a similar way for chemical-energy storage. In terms of capacities, the limits of batteries (accumulators) are reached when low-loss long-term storage is of need. Chemical-energy storage and stocking fulfills these requirements completely. The storing itself may be subject to significant efficiency losses, but, from today’s point of view and in combination with the existing gas and fuel infrastructure, it is the only national option with regards to the long-term storage of renewable energies. Chemical-energy storage is the backbone of today’s conventional energy supply. Solid (wood and coal), liquid (mineral oil), and gaseous (natural gas) energy carriers are ‘energy storages’ themselves, and are stored using different technologies. In the course of energy transition, chemical-energy storage will be of significant importance, mainly as long-term storage for the power sector, but also in the form of combustibles and fuels for transport and heat. Not only are conventional storing technologies discussed within this chapter, but a detailed explanation is also given about the storage of renewable energies in the form of gaseous (power-to-gas, PtG) and liquid (power-to-liquid, PtL) energy carriers for electricity, heat, chemicals, and in the form of synthetic fuels. Y1 - 2019 SN - 978-3-662-55503-3 U6 - https://doi.org/10.1007/978-3-662-55504-0_8 SP - 325 EP - 482 PB - Springer CY - Berlin, Heidelberg ER - TY - JOUR A1 - Sorokin, Vladislav V. A1 - Belyaeva, Inna A. A1 - Shamonin (Chamonine), Mikhail A1 - Kramarenko, Elena Yu T1 - Magnetorheological response of highly filled magnetoactive elastomers from perspective of mechanical energy density: Fractal aggregates above the nanometer scale? JF - Physical Review E N2 - The dynamic shear modulus of magnetoactive elastomers containing 70 and 80 mass % of carbonyl iron microparticles is measured as a function of strain amplitude via dynamic torsion oscillations in various magnetic fields. The results are presented in terms of the mechanical energy density and considered in the framework of the conventional Kraus model. The form exponent of the Kraus model is further related to a physical model of Huber et al. [Huber et al., J. Phys.: Condens. Matter 8, 409 (1996)] that uses a realistic representation for the cluster network possessing fractal structure. Two mechanical loading regimes are identified. At small strain amplitudes the exponent beta of the Kraus model changes in an externally applied magnetic field due to rearrangement of ferromagnetic-filler particles, while at large strain amplitudes, the exponent beta seems to be independent of the magnetic field. The critical mechanical energy characterizing the transition between these two regimes grows with the increasing magnetic field. Similarities between agglomeration and deagglomeration of magnetic filler under simultaneously applied magnetic field and mechanical shear and the concept of jamming transition are discussed. It is proposed that the magnetic field should be considered as an additional parameter to the jamming phase diagram of rubbers filled with magnetic particles. KW - BEHAVIOR KW - composites KW - hysteresis KW - MAGNETIC-FIELD KW - MODEL KW - RHEOLOGY KW - RUBBER KW - SENSITIVE ELASTOMERS KW - VISCOELASTIC PROPERTIES Y1 - 2017 U6 - https://doi.org/10.1103/PhysRevE.95.062501 VL - 95 IS - 6 PB - Amer Physical Soc ER -