@misc{SaadiCunninghamAbdelmaliketal., author = {Saadi, Ibtissam and Cunningham, Douglas W. and Abdelmalik, Taleb-Ahmed and Hadid, Abdenour and El Hillali, Yassin}, title = {Driver's facial expression recognition using global context vision transformer}, series = {2023 IEEE International Conference on Computer Vision and Machine Intelligence (CVMI)}, journal = {2023 IEEE International Conference on Computer Vision and Machine Intelligence (CVMI)}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {979-8-3503-0514-2}, doi = {10.1109/CVMI59935.2023.10464794}, pages = {1 -- 8}, abstract = {Driver's facial expression recognition plays a critical role in enhancing driver safety, comfort, and overall driving experience by proactively mitigating potential road risks. While most existing works in this domain rely on CNN - based approaches, this paper proposes a novel method for driver facial expression recognition using Global Context Vision Transformer (DFER-GCViT). With its inherent capabilities of transformer-based architectures and global context modeling, the proposed method handles challenges commonly encountered in real-world driving scenarios, including occlusions, head pose variations, and illumination conditions. Our method consists of three modules: preprocessing for face detection and data augmentation, facial feature extraction of local and global features, and expression classification using a modified GC-ViT classifier. To evaluate the performance of DFER-GCViT, extensive experiments are conducted on two benchmarking datasets namely the KMU-FED driver facial expression dataset and FER2013 general facial expression dataset. The experimental results demonstrate the superiority of DFER-GCViT in accurately recognizing driver's facial expressions, achieving an average accuracy of 98.27 \% on the KMU-FED dataset and 73.78\% on the FER2013 dataset, outperforming several state-of-the-art methods on these two benchmarking datasets.}, language = {en} } @misc{LengyelToulouse, author = {Lengyel, Dominik and Toulouse, Catherine}, title = {Landscapes in visualisations of architectonic hypotheses}, series = {XXI International Forum Le vie dei Mercanti World Heritage and Dwelling on Earth}, journal = {XXI International Forum Le vie dei Mercanti World Heritage and Dwelling on Earth}, address = {Napoli}, isbn = {978-88-492-4646-9}, language = {en} } @misc{FritzscheAbbasov, author = {Fritzsche, Pascal Dirk and Abbasov, Ilgar}, title = {Chip formation and shaping in milling machining of light metal casting materials}, series = {Key Engineering Materials}, volume = {979}, journal = {Key Engineering Materials}, publisher = {Trans Tech Publications Ltd.}, address = {Wollerau}, issn = {1662-9795}, doi = {10.4028/p-TftpU0}, pages = {3 -- 10}, abstract = {The main purpose of the research is to study the floating chips produced during mechanical processing. Chips derived from aluminium material cause several difficulties in mechanical processing. Research shows that floating chips clog filters in chip conveyors, resulting in significant downtime in production processes. In this article, cause-effect research has been carried out to find approaches to solving this problem.}, language = {en} } @misc{GernandtKrenzlinHagemannetal., author = {Gernandt, Hannes and Krenzlin, Franziska and Hagemann, Willem and Schiffer, Johannes}, title = {Data-based modeling for optimizing the operation of seasonal underground storages}, series = {Der Geothermiekongress 2023 : 17.-19. Oktober 2023 in Essen : Tagungsband}, journal = {Der Geothermiekongress 2023 : 17.-19. Oktober 2023 in Essen : Tagungsband}, address = {Essen}, organization = {Geothermische Vereinigung - Bundesverband Geothermie}, pages = {6}, abstract = {Underground thermal energy storages (UTES) are essential for decarbonizing the existing heating networks. To accurately simulate the storage and the connected heat supply system, typically detailed numerical models of the UTES and the heat supply system are required. In a co-simulation these models must be coupled, which is often time-consuming and has therefore not been used to operate systems in real-time. In this contribution, we present a method that leads to a data-based surrogate model of low complexity, which can then be directly integrated in the operational optimization. To illustrate the method, we derive a surrogate model from a Feflow model of a borehole thermal energy storage (BTES) as a particular type of UTES and integrate the surrogate model into a supply system that is optimized for electrical energy consumption using the Python toolbox Pyomo.}, language = {de} } @misc{SchachtGruenNowaketal., author = {Schacht, Ralph and Gruen, Tobias and Nowak, Torsten and Arnold, J{\"o}rg and May, Daniel and Wunderle, Bernhard}, title = {Experimental investigation of pumped two-phase flow boiling using different finned and pin finned structures on interchangeable heater modules}, series = {29th International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)}, journal = {29th International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)}, doi = {10.1109/THERMINIC60375.2023.10325896}, abstract = {This paper introduces an industry-grade, multipurpose closed loop flow boiling cooler test stand for rapid experimental characterization and parameter variation. A flow boiling chamber with interchangeable plug-in heater module was designed that allows for the investigation of different finned cooler structures and surface topologies and chemistry respectively to enhance small bubble formation and release. In this experimental investigation a finned and a pin finned cooler structure using mm-size dimensions were used. It could be shown that the pin finned and finned cooler structure show for low flow rates at low pressure drop the same performance. Furthermore, it could be observed that the heat transfer coefficient could be increased for both cooler structure in the two-phase regime as opposed to single-phase convective liquid cooling.}, language = {en} } @misc{DorneanuMechleriArellanoGarcia, author = {Dorneanu, Bogdan and Mechleri, Evgenia and Arellano-Garc{\´i}a, Harvey}, title = {Towards smart distributed energy systems}, series = {Jahrestreffen der ProcessNet-Fachgemeinschaften "Prozess-, Apparate- und Anlagentechnik" (PAAT)}, journal = {Jahrestreffen der ProcessNet-Fachgemeinschaften "Prozess-, Apparate- und Anlagentechnik" (PAAT)}, pages = {1}, abstract = {A distributed energy resource (DER) system is an energy generation system located in the vicinity of the end users, simultaneously providing electricity, cooling and heating to meet the demands of the local users1. Unlike conventional, centralized energy supply, a DER system typically employs a wide range of technologies such as photovoltaics, wind turbines, gas turbines, biomass boilers, combined heating and power, absorption chillers, etc. In addition, energy storage technologies (batteries, hot/cold water storage) are available as well. DER systems can potentially play a vital role as the energy sector faces unprecedented challenges to reduce emissions by increasing energy generation using renewable and low-carbon energy resources. Different designs of the DER systems could lead to different performance in reducing the costs, the environmental impact or the use of primary energy. Hence, optimal design and management of complex DER systems are important tasks to promote their diffusion against the centralized grid. However, current operational models for DERs do not adequately analyse the complexity of such systems. This contribution presents a set of models for the optimal design and operation of residential DER systems, which build up on previous work in this field, and aims to provide a more holistic overview of such systems. For each node in the DER system, there is an option of installing the following ten technologies: wind turbines, photovoltaics arrays, combined heating and power units, absorption chillers, air-conditioning units, gas boilers, biomass boilers, gas heaters, batteries and thermal storage. Only one of each item may be installed in each home. There is also the option to connect a house to another via a combined hot and cold water pipeline and/or a microgrid cable, to share thermal and electrical energy, respectively. Due to increased availability of government incentives such as the feed-in tariffs (FIT) and renewable heat incentives (RHI) payments, these are included in the model as well. The increased penetration of Internet of Things technology and their potential to better control and optimize DER systems enable its use to help stabilize national grids. To this end, the models include the use of dynamic pricing, a strategy in which national grids publish in real time variable prices for electricity within given time periods. Furthermore, as current literature's focus on economic and environmental cost minimization, which do not satisfy long-term sustainability priorities through the rational use of energy resources, the introduction of a third criteria, exergy, is investigated. A third novelty of this contribution is the consideration of a multi-objective optimization which simultaneously includes the three objectives: the economic, the environmental and exergetic criteria in the design and operation of the residential DER system. Additionally, a novel methodology to analyse the effect of uncertain input variables on the total daily cost of the DER operational models. The methodology combines the operational model with model predictive control to predict the current state of the model. A subset of the model inputs (i.e., electricity demand, heating demand, and insolation) are considered uncertain. Global sensitivity analysis is conducted to quantify and understand how the uncertain variables influence, both individually and through interactions, the total daily cost. Finally, the implementation of blockchain technology and smart contracts within optimally designed and scheduled DER systems is investigated, to assess the advantages of smart technologies on the efficiency of residential DERs. Challenges, limitations and suggestions for improving the overall design and operation are also discussed in detail. All models are developed as mixed-integer linear programming models implemented and solved in GAMS, and show significant reduction of costs for all considered criteria when compared to the centralised grid and the classical approach towards the modelling of DER systems.}, language = {en} } @misc{RabensteinNguyenGierschetal., author = {Rabenstein, Jonas and Nguyen, Dustin and Giersch, Oliver and Eichler, Christian and H{\"o}nig, Timo and Nolte, J{\"o}rg and Schr{\"o}der-Preikschat, Wolfgang}, title = {Back to the core-memory age: running operating systems in NVRAM only}, series = {Proceedings: architecture of computing systems: 36th International Conference, ARCS 2023, June 13 - 15, 2023}, journal = {Proceedings: architecture of computing systems: 36th International Conference, ARCS 2023, June 13 - 15, 2023}, editor = {Goumas, Georgios and Tomforde, Sven and Brehm, J{\"u}rgen and Wildermann, Stefan and Pionteck, Thilo}, publisher = {Springer-Verlag}, isbn = {978-3-031-42784-8}, doi = {10.1007/978-3-031-42785-5_11}, pages = {153 -- 167}, abstract = {The classic core memory was completely non-volatile and thus kept at least part of the operating system persistently in main memory, even over power cycles. Nowadays we can repeat this approach with NVRAM, but with terabytes of main memory on a completely different scale and with parts of the operating-system state stored in volatile CPU caches. In this paper, we discuss our experiences of running large modern operating systems including their applications entirely in NVRAM. We adapted stock Linux and FreeBSD kernels to work exclusively with NVRAM by hiding all DRAM from the kernels at boot time to establish a realistic performance baseline without changing anything else. Following this entirely NVRAM-agnostic approach, we could observe an effective performance penalty of a factor of about four, but only negligible increases in whole-system power draw. For our system with two CPU sockets and 56 cores total, we also observed a reduction in power draw in several scenarios. Due to prolonged execution times, the energy consumption increased as well for these measured workloads. While this might be discouraging at first sight, this result was achieved without any performance tuning as to the specific characteristics of today's NVRAM technology. Therefore, we are also discussing means to mitigate the observed shortcomings by integrating NVRAM appropriately into the memory hierarchy of future robust persistent systems.}, language = {en} } @misc{KettelgerdesMezmerHaeussleretal., author = {Kettelgerdes, Marcel and Mezmer, Peter and Haeussler, Michael J. and B{\"o}ttger, Gunnar and Tavakolibasti, Majid and Pandey, Amit and Erdogan, H{\"u}seyin and Elger, Gordon and Schacht, Ralph and Wunderle, Bernhard}, title = {Realization, multi-field coupled simulation and characterization of a thermo-mechanically robust LiDAR front end on a copper coated glass substrateier den Haupttitel eintragen}, doi = {10.1109/ECTC51909.2023.00131}, abstract = {The thermo-mechanical robustness of Advanced Driving Assistance Systems is crucial to leverage the growing market of automated driving. Especially in case of optical sensors, such as camera and Light Detection and Ranging (LiDAR) sensors, the thermo-mechanical state of the sensor front end is closely coupled with its optical performance. Deformations in the optical path, consisting of the lens elements and imager, can cause major performance degradation like defocus. Additionally, the big Coefficient of Thermal Expansion (CTE) mismatch between the commonly used FR4 substrate and large silicon (time-off light) imagers, leads to extraordinary mechanical stress in the respective interconnects if operated under harsh automotive temperature conditions. Hence, within this work, an optical LiDAR front end on glass is realized in the form of reduced complexity modules (RCMs) of the transmitter and receiver path. The transmitter RCM, consisting of a variety of small glass mounted high power Vertical Cavity Surface Emitting Laser (VCSEL) diodes is tested and evaluated with respect to lifetime reliability, whereas the receiver RCM, consisting of a glass mounted large-scale imager, is firstly investigated with regard to cooling under high temperature operation.}, language = {en} } @misc{Maltzahn, author = {Maltzahn, Julia von}, title = {Muscle stem cells in age and disease}, series = {ERIBA : University Medical Center Groningen (UMCG), The Netherlands, 28 - 30 September 2023}, journal = {ERIBA : University Medical Center Groningen (UMCG), The Netherlands, 28 - 30 September 2023}, doi = {10.5281/zenodo.10673943}, pages = {34}, language = {en} } @misc{UhlmannRizziWenetal., author = {Uhlmann, Max and Rizzi, Tommaso and Wen, Jianan and P{\´e}rez-Bosch Quesada, Emilio and Al Beattie, Bakr and Ochs, Karlheinz and P{\´e}rez, Eduardo and Ostrovskyy, Philip and Carta, Corrado and Wenger, Christian and Kahmen, Gerhard}, title = {LUT-based RRAM model for neural accelerator circuit simulation}, series = {Proceedings of the 18th ACM International Symposium on Nanoscale Architectures}, journal = {Proceedings of the 18th ACM International Symposium on Nanoscale Architectures}, publisher = {ACM}, address = {New York, NY, USA}, doi = {10.1145/3611315.3633273}, pages = {1 -- 6}, abstract = {Neural hardware accelerators have been proven to be energy-efficient when used to solve tasks which can be mapped into an artificial neural network (ANN) structure. Resistive random-access memories (RRAMs) are currently under investigation together with several different memristive devices as promising technologies to build such accelerators combined together with complementary metal-oxide semiconductor (CMOS)-technologies in integrated circuits (ICs). While many research groups are actively developing sophisticated physical-based representations to better understand the underlying phenomena characterizing these devices, not much work has been dedicated to exploit the trade-off between simulation time and accuracy in the definition of low computational demanding models suitable to be used at many abstraction layers. Indeed, the design of complex mixed-signal systems as a neural hardware accelerators requires frequent interaction between the application- and the circuit-level that can be enabled only with the support of accurate and fast-simulating devices' models. In this work, we propose a solution to fill the aforementioned gap with a lookup table (LUT)-based Verilog-A model of IHP's 1-transistor-1-RRAM (1T1R) cell. In addition, the implementation challenges of conveying the communication between the abstract ANN simulation and the circuital analysis are tackled with a design flow for resistive neural hardware accelerators that features a custom Python wrapper. As a demonstration of the proposed design flow and 1T1R model, an ANN for the MNIST handwritten digit recognition task is assessed with the last layer verified in circuit simulation. The obtained recognition confidence intervals show a considerable discrepancy between the purely application-level PyTorch simulation and the proposed design flow which spans across the abstraction layers down to the circuital analysis.}, language = {en} } @misc{ElserKopkowSchaefer, author = {Elser, Alexander and Kopkow, Christian and Sch{\"a}fer, Axel}, title = {Barrieren und F{\"o}rderfaktoren bei der Implementierung einer Virtual Reality Intervention in die ambulante physiotherapeutische Versorgung von Menschen mit chronischen Schmerzen: eine Mixed- Methods Beobachtungsstudie}, series = {7. Forschungssymposium Physiotherapie der Deutschen Gesellschaft f{\"u}r Physiotherapiewissenschaft e.V.}, volume = {20}, journal = {7. Forschungssymposium Physiotherapie der Deutschen Gesellschaft f{\"u}r Physiotherapiewissenschaft e.V.}, number = {S 01}, publisher = {Thieme}, doi = {10.1055/s-0043-1777872}, abstract = {Hintergrund F{\"u}r die Therapie von chronischen Schmerzen wird eine multimodale Therapie unter Einbezug von kognitiver und verhaltensorientierter Therapie empfohlen (Malfliet et al. 2019). In der ambulanten Versorgung ist dies nur schwer umsetzbar, da in der Psychotherapie lange Wartezeiten bestehen (BPtK, 2021) und eine enge Abstimmung zwischen den Professionen notwendig ist (Pfingsten et al., 2019). Virtual Reality (VR)-Interventionen bieten eine M{\"o}glichkeit, den psychologischen Anteil einer multimodalen Therapie standardisiert und in den Einrichtungen anderer Professionen zu erbringen. Die Evidenz f{\"u}r die Therapie mit VR bei chronischen Schmerzen wird zunehmend robuster. Sie zeigt positive Effekte in Bezug auf Schmerzreduktion und k{\"o}rperliche Funktion (Goudman et al., 2022). Um innovative VR-Interventionen fl{\"a}chendeckend in die ambulante Physiotherapie in Deutschland zu integrieren, bedarf es einer gezielten und systematischen Implementierungsstrategie. Diese kann auf Grundlage von zuvor gesammelten Barrieren und F{\"o}rderfaktoren entwickelt werden. Fragestellung Was sind aus Sicht von Praxisinhaber*innen und Physiotherapeut*innen Barrieren und F{\"o}rderfaktoren bei der Implementierung einer VR-Intervention f{\"u}r Menschen mit chronischen Schmerzen? Methode Im Rahmen einer vierphasigen Implementierungsstudie werden mittels 1 Fokusgruppe und 3 semi-strukturierten Interviews mit Praxisinhaber*innen sowie 1 Online-Befragung und 6 semi-strukturierten Interviews mit Therapeut*innen Barrieren und F{\"o}rderfaktoren f{\"u}r die Implementierung einer VR-Intervention in ambulanten Praxen erhoben. Leitf{\"a}den werden entwickelt, um die VR-Intervention hinsichtlich ihrer Akzeptabilit{\"a}t, Angemessenheit, Machbarkeit, Umsetzungsbereitschaft und Umsetzungstreue zu untersuchen. Die Auswertung erfolgte mittels einer strukturierenden Inhaltsanalyse nach Kuckartz (Kuckartz und R{\"a}diker, 2022), wobei das Theoretical Domains Framework (TDF; Cane, 2012) als Grundlage f{\"u}r die Kategorienbildung dient. Ergebnisse Die identifizierten Barrieren und F{\"o}rderfaktoren werden getrennt f{\"u}r Therapeut*innen und Praxisinhaber*innen dargestellt. Zum Zeitpunkt des Einreichens des Abstracts liegen noch keine Ergebnisse vor. Diskussion Die Ergebnisse werden unter Ber{\"u}cksichtigung der Limitationen in die aus der Literatur bekannten Barrieren und F{\"o}rderfaktoren eingeordnet und diskutiert. Dar{\"u}ber hinaus wird eine initiale Implementierungsstrategie auf Grundlage der gewonnenen Daten vorgestellt.}, language = {de} } @misc{BahnsBremerMenkeetal., author = {Bahns, Carolin and Bremer, Alexander and Menke, Chiara Julia and Napierala-Komp, Simone and Hauke, Jeannine and Glaubitz, Andreas and Kopkow, Christian}, title = {Programmevaluation von GLA:D ® Deutschland: vorl{\"a}ufige Ergebnisse einer Mixed-Methods-Studie unter Verwendung des RE-AIM QuEST Frameworks}, series = {7. Forschungssymposium Physiotherapie der Deutschen Gesellschaft f{\"u}r Physiotherapiewissenschaft e.V.}, volume = {20}, journal = {7. Forschungssymposium Physiotherapie der Deutschen Gesellschaft f{\"u}r Physiotherapiewissenschaft e.V.}, number = {S 01}, publisher = {Thieme}, doi = {10.1055/s-0043-1777893}, language = {de} } @misc{BahnsBremerMenkeetal., author = {Bahns, Carolin and Bremer, Alexander and Menke, Chiara Julia and Napierala-Komp, Simone and Hauke, Jeannine and Glaubitz, Andreas and Kopkow, Christian}, title = {Implementierung von GLA:D ® in Deutschland - Effektivit{\"a}t im Nachuntersuchungszeitraum von 3 Monaten}, series = {7. Forschungssymposium Physiotherapie der Deutschen Gesellschaft f{\"u}r Physiotherapiewissenschaft e.V.}, volume = {20}, journal = {7. Forschungssymposium Physiotherapie der Deutschen Gesellschaft f{\"u}r Physiotherapiewissenschaft e.V.}, number = {S 01}, publisher = {Thieme}, doi = {10.1055/s-0043-1777892}, language = {de} } @misc{ElserLangeKopkowetal., author = {Elser, Alexander and Lange, Marina and Kopkow, Christian and Sch{\"a}fer, Axel}, title = {Erfahrungen bei der Implementierung von Virtual Reality Interventionen zur Behandlung von Menschen mit chronischen Schmerzen: ein Scoping Review}, series = {7. Forschungssymposium Physiotherapie der Deutschen Gesellschaft f{\"u}r Physiotherapiewissenschaft e.V.}, volume = {20}, journal = {7. Forschungssymposium Physiotherapie der Deutschen Gesellschaft f{\"u}r Physiotherapiewissenschaft e.V.}, number = {S 01}, publisher = {Thieme}, doi = {10.1055/s-0043-1777904}, language = {de} } @misc{BahnsKopkow, author = {Bahns, Carolin and Kopkow, Christian}, title = {Barrieren und F{\"o}rderfaktoren in der Umsetzung leitliniengerechter Versorgung von Patient*innen mit H{\"u}ft- und/oder Kniegelenkarthrose in der physiotherapeutischen Praxis: eine qualitative Interviewstudie}, series = {7. Forschungssymposium Physiotherapie der Deutschen Gesellschaft f{\"u}r Physiotherapiewissenschaft e.V.}, volume = {20}, journal = {7. Forschungssymposium Physiotherapie der Deutschen Gesellschaft f{\"u}r Physiotherapiewissenschaft e.V.}, number = {S 01}, publisher = {Thieme}, doi = {10.1055/s-0043-1777891}, language = {de} } @misc{LengyelSpinelliDimova, author = {Lengyel, Dominik and Spinelli, Jacopo and Dimova, Lyubov}, title = {New Scale Model of the City of Pergamon}, series = {EVA Berlin 2023 Conference, 30. November - 01. Dezember 2023, Kunstgewerbemuseum (Museum of Decorative Arts)}, journal = {EVA Berlin 2023 Conference, 30. November - 01. Dezember 2023, Kunstgewerbemuseum (Museum of Decorative Arts)}, address = {Berlin}, pages = {141 -- 148}, language = {en} } @misc{Sheikhi‐GarjanGiustolisiSchuermann, author = {Sheikhi-Garjan, Maryam and Giustolisi, Rosario and Schuermann, Carsten}, title = {Receipt-Free Electronic Voting from zk-SNARK}, series = {Proceedings of the 20th International Conference on Security and Cryptography}, journal = {Proceedings of the 20th International Conference on Security and Cryptography}, publisher = {SCITEPRESS - Science and Technology Publications}, isbn = {978-989-758-666-8}, doi = {10.5220/0012140000003555}, pages = {254 -- 266}, language = {en} } @misc{BahnsKopkow, author = {Bahns, Carolin and Kopkow, Christian}, title = {Barrieren und F{\"o}rderfaktoren in der Umsetzung leitliniengerechter Versorgung von Patient*innen mit H{\"u}ft- und/oder Kniegelenksarthrose in der physiotherapeutischen Praxis: Eine qualitative Interviewstudie}, series = {22. Deutscher Kongress f{\"u}r Versorgungsforschung (DKVF), Berlin, 04.-06.10.2023}, journal = {22. Deutscher Kongress f{\"u}r Versorgungsforschung (DKVF), Berlin, 04.-06.10.2023}, publisher = {German Medical Science}, address = {D{\"u}sseldorf}, doi = {10.3205/23dkvf140}, abstract = {Hintergrund und Stand der Forschung: H{\"u}ft- und Kniegelenksarthrose ist eine in der Bev{\"o}lkerung weitverbreitete Erkrankung, die mit einer deutlichen Einschr{\"a}nkung der Lebensqualit{\"a}t sowie hohen Kosten f{\"u}r das Gesundheitssystem einhergeht. Leitlinien fassen die Evidenz verschiedener diagnostischer und therapeutischer Maßnahmen zusammen und sollen so Angeh{\"o}rigen der Gesundheitsberufe und Patient*innen als Entscheidungshilfe in der medizinischen Versorgung dienen. Aktuelle Untersuchungen zeigen jedoch, dass Physiotherapeut*innen in der Behandlung von H{\"u}ft- und Kniegelenksarthrose h{\"a}ufig von den in Leitlinien formulierten Empfehlungen abweichen. Die Gr{\"u}nde f{\"u}r das Nichteinhalten von Leitlinienempfehlungen sind komplex und umfassen pers{\"o}nliche Barrieren, z.B. das eigene Wissen und Einstellungen, sowie leitlinienbezogene und externe Faktoren. Landesspezifischen Barrieren wird dabei ebenfalls eine besondere Rolle zugesprochen. Fragestellung und Zielsetzung: Das Ziel der Studie ist die Erfassung von Barrieren und F{\"o}rderfaktoren in Bezug auf die Anwendung von Leitlinien in der physiotherapeutischen Versorgung von Patient*innen mit H{\"u}ft- und/oder Kniegelenksarthrose in Deutschland. Folgende Fragestellungen sollen beantwortet werden: 1. Welche Faktoren beeinflussen die Nutzung von Leitlinien in der physiotherapeutischen Praxis? 2. Was muss ver{\"a}ndert werden, damit die Empfehlungen aus Arthrose-Leitlinien h{\"a}ufiger umgesetzt werden? Methode: Im Fr{\"u}hjahr 2023 werden semi-strukturierte Interviews mit in der ambulanten Versorgung t{\"a}tigen Physiotherapeut*innen durchgef{\"u}hrt. {\"U}ber die Auswahl einer gezielten Stichprobe („Purposive Sampling") anhand von Alter, Geschlecht, Berufserfahrung und Ausbildungsniveau soll ein m{\"o}glichst breites Spektrum an Informationen abgebildet werden. Der Interviewleitfaden wurde mithilfe des Theoretical Domains Framework (TDF) entwickelt und in zwei Pilotinterviews vorab getestet. Die Interviews werden aufgezeichnet, transkribiert und inhaltsanalytisch nach Braun und Clarke ausgewertet. Ergebnisse: Die Erhebung ist zum Sommer 2023 abgeschlossen und die Ergebnisse sollen im Rahmen des Deutschen Kongresses f{\"u}r Versorgungsforschung (DKVF) 2023 pr{\"a}sentiert werden. Diskussion: Ein optimaler Weg zur Implementierung von Leitlinien scheint noch nicht gefunden zu sein. Eine Ver{\"a}nderung im Verhalten der Behandelnden steht h{\"a}ufig im Fokus von Interventionen und ist essenziell f{\"u}r die erfolgreiche Implementierung von Leitlinien. Expert*innen empfehlen die Verwendung theoretischer Modelle, um Hindernisse in der Umsetzung von Leitlinien zu verstehen und um die Auswahl geeigneter Maßnahmen zu informieren. Eine Untersuchung (landes-)spezifischer Barrieren ist daher eine wichtige Voraussetzung f{\"u}r die Entwicklung einer zielgerichteten Implementierungsintervention, welche langfristig zu einer verbesserten Qualit{\"a}t der Gesundheitsversorgung beitragen soll. Implikation f{\"u}r die Versorgung: Unter Ber{\"u}cksichtigung der identifizierten Barrieren und F{\"o}rderfaktoren sollen anschließend mithilfe des Behaviour Change Wheel (BCW) systematisch relevante Maßnahmen zur Verhaltens{\"a}nderungen geplant werden.}, language = {de} } @misc{GrandasTaveraWichtmannMachačeketal., author = {Grandas Tavera, Carlos Eduardo and Wichtmann, Torsten and Machaček, Jan and Nitsch, Antonia}, title = {An extended theory of porous media for expansive soils}, series = {10th European Conference on Numerical Methods in Geotechnical Engineering (NUMGE2023)}, journal = {10th European Conference on Numerical Methods in Geotechnical Engineering (NUMGE2023)}, editor = {Zdravkovic, Lidija and Kontoe, Stavroula and Tsiampousi, Aikaterini and Taborda, David}, doi = {10.53243/NUMGE2023-379}, pages = {6}, abstract = {The successful simulation of the behaviour of expansive soils using FEM strongly depends on the acting hydromechanical processes and their proper consideration. During swelling processes, part of the pore water is bound to the solid. However, the associated change of volume fractions in the porous medium and its contribution to the overall material behaviour is not accounted for in most numerical frameworks. A numerical framework based on the theory of porous media and a novel constitutive model is proposed. The theory of porous media includes a distinct swelling water phase that does not participate in the flow through the pore space. A bidirectional mass transport enables the transition from free to swelling water during change in water content. The reduction of the effective pore space is considered at the finite element level. By consistent balancing in the governing equations, the swelling induced reduction of hydraulic conductivity is directly accounted for. The performance of the proposed framework is demonstrated by back calculation of laboratory tests on different materials. Its capabilities to simulate complex loading paths in (un)saturated conditions with a single set of parameters are shown.}, language = {en} } @misc{GrandasTaveraCudmaniCsuka, author = {Grandas Tavera, Carlos Eduardo and Cudmani, Roberto and Csuka, Antal}, title = {Numerical investigations of the influence of initial static shear stress on the bi-directional loading of dense sand}, series = {10th European Conference on Numerical Methods in Geotechnical Engineering (NUMGE2023)}, journal = {10th European Conference on Numerical Methods in Geotechnical Engineering (NUMGE2023)}, editor = {Zdravkovic, Lidija and Kontoe, Stavroula and Tsiampousi, Aikaterini and Taborda, David}, doi = {10.53243/NUMGE2023-45}, pages = {6}, abstract = {Advanced constitutive models are required for realistic prediction of the seismic behavior of geotechnical structures, such as dams and embankments, under undrained alternating loading conditions. The constitutive models should be able to capture accurately two important aspects related to the boundary value problem: the influence of a non-zero initial static shear stress and the multi-directional nature of the earthquake loading. Experimental studies show that the deformation characteristics of granular materials under undrained cyclic loading conditions depend on the initial static shear stress, initial void ratio and loading direction. In this paper, two advanced constitutive models from the hypoplasticity family are compared with each other and with experiments regarding to their ability to account for the influence of the initial static shear stress on liquefaction.}, language = {en} } @misc{SchneiderRoehl, author = {Schneider, Peter Iren{\"a}us and R{\"o}hl, Constanze}, title = {Von Tr{\"u}mmern und Troph{\"a}en. Demontage, Sprengung und R{\"u}ckbau der Fertigungshalle 1 in Peenem{\"u}nde als Teil der Baugeschichte}, series = {Sur le Grand Tour - Reisende Architekten als Protagonisten des europ{\"a}ischen Gedankens. Tagung vom 12. bis 14. M{\"a}rz 2021}, journal = {Sur le Grand Tour - Reisende Architekten als Protagonisten des europ{\"a}ischen Gedankens. Tagung vom 12. bis 14. M{\"a}rz 2021}, editor = {Kienlin, Alexander von}, edition = {1. Auflage}, publisher = {Thelem}, address = {Dresden}, isbn = {978-3-95908-532-8}, pages = {163 -- 170}, language = {de} } @misc{WendlandGielen, author = {Wendland, David and Gielen, Mark}, title = {Some considerations on the early development of cross vaults and rib vaults in medieval architecture}, series = {Studies in Construction History : the Proceedings of the Tenth Annual Conference of the Construction History Society : Queen's College, University of Cambridge, 12-13 April 2023}, journal = {Studies in Construction History : the Proceedings of the Tenth Annual Conference of the Construction History Society : Queen's College, University of Cambridge, 12-13 April 2023}, editor = {Campbell, James}, publisher = {Construction History Society}, address = {Cambridge}, isbn = {978-0-9928751-9-0}, pages = {29 -- 42}, abstract = {The fundamental shift in the geometric design of cross vaults that gave way to the development of Gothic vaults is usually associated with the introduction of cross ribs built with cut stone. And it is generally assumed that the development of the rib vault occurred in Norman architecture shortly before 1100, from where it was introduced to early Gothic vault architecture. In particular, the requirements of stone planning in the ribs has been interpreted as a guiding feature of the geometric design of the vaults. However, surveys and geometric analyses carried out in some prominent vaulted structures suggest that this innovation in the geometric concept of vaults may have taken place at an earlier date, and that this development has a more complex relation to the use of ribs than it has been generally assumed. We discuss this in case studies on the geometric concept of the cross vaults in the Palatine Chapel at Aachen and in the two medieval building phases of Speyer Cathedral. In the latter, archaeological evidence shows that in the complex, wide spanned high vault of the nave one original bay still survives from the late 11th century. The research in progress on the earliest known rib vaults in central European architecture also raises questions regarding the early history of stereotomy. In the lack of written or graphic sources about the design and building technology in these structures, the built object is an essential source for understanding the decision-making processes in planning of complex spatial structures stable by their shape. The interpretation of the geometric data and the evidence from building archaeology gives an insight also on the background of knowledge in the design of highly demanding spatial structures in the middle-ages.}, language = {en} } @misc{ChatharajupalliRottaKarnapkeetal., author = {Chatharajupalli, Navya Sneha and Rotta, Randolf and Karnapke, Reinhardt and Nolte, J{\"o}rg}, title = {Assessing the Feasibility of Combined BLE and Wi-Fi Communication for High Data Sensing Applications}, series = {EWSN '23: Proceedings of the 2023 International Conference on Embedded Wireless Systems and Networks}, journal = {EWSN '23: Proceedings of the 2023 International Conference on Embedded Wireless Systems and Networks}, publisher = {Association for Computing Machinery}, address = {New York}, doi = {10.5555/3639940.3639948}, pages = {56 -- 59}, abstract = {Advanced sensors generate more data than can be transmitted using classic battery-powered wireless sensor networks. While using Wi-Fi would provide plenty of throughput, the receivers are energy hungry and, thus, the radio time needs to be reduced. Previous research suggests to combine Wi-Fi with low-power technologies such as BLE for an energy efficient coordination of the Wi-Fi radios. Existing approaches focus on individual point-to-point routes whereas certain applications require concurrent transmissions. We evaluated the combination of BLE and Wi-Fi on the ESP32-S3 multi-radio microcontroller through detailed energy and throughput measurements. The results show that established BLE connections allow to activateWi-Fi quickly on-demand; the energy efficiency of the data transmission is significantly improved over previous works but the BLE connection setup is prohibitively slow. While the combination of BLE and Wi-Fi provides high throughput with good energy efficiency, careful design of the BLE-based signalling protocol is necessary to also achieve low latency.}, language = {en} } @misc{Schmitt, author = {Schmitt, Rebecca Erika}, title = {The geometric design of Christoph Dientzenhofer's 'radical' vaults}, series = {Studies in Construction History: Proceedings of the Tenth Annual Conference of the Construction History Society}, volume = {2023}, journal = {Studies in Construction History: Proceedings of the Tenth Annual Conference of the Construction History Society}, editor = {Campbell, James}, publisher = {Construction History Society}, address = {Cambridge}, isbn = {978-0-9928751-9-0}, doi = {10.26127/BTUOpen-6408}, pages = {143 -- 155}, abstract = {Christoph Dientzenhofer (1655-1722) is considered one of the most important Baroque master builders of Central Europe. From his extensive architectural oeuvre, a group of six church buildings with geometrically complex forms stands out, recognised by architectural historians as particularly innovative and influential. These churches, located in Bohemia (Czech Republic), and often collectively referred to as the 'radical', 'dynamic', 'Guarinesque', or simply 'Bohemian' group, are: St. Joseph in Obořiště (1702-11), the Castle Church in Smiřice (1702-11), St. Nicholas in the Lesser Town of Prague (1703-11), St. Clare in Cheb (1707-11), St. Margaret in Břevnov (1708-16), and the Church of the Holy Assumption in Nov{\´a} Paka (1709-24). The brick vaults of these six buildings, sequences of oval domes and double-curved vault areas, are of particular interest for building research. In this study, the geometric design of the vaults of Dientzenhofer's 'radical' churches is documented, analysed, and compared using 3D laser scans of the buildings as primary source. The 3D models generated from the scans enable a geometric analysis through the method of reverse geometric engineering, breaking down the vaults' complex three-dimensional forms into their basic two-dimensional components: segments of circles with different radii and orientations, curved in one or two directions. These forms can be found in the architectural and stereotomic treatises that were widespread at the time. By comparing the vault geometry of the six churches with each other and with the geometric concepts discussed in the treatises, general statements can be made about the architect's design choices. On the basis of this investigation, hypotheses are made about the design and underlying geometric ideas of the vaults of Dientzenhofer's 'radical group', and the results are placed in context.}, language = {en} } @misc{Lengenfeld, author = {Lengenfeld, Jonas}, title = {Some points on the construction of high medieval slewing cranes in towers in Germany based on Building archaeology and a new find from the early 13th century}, series = {Studies in Construction History : the Proceedings of the Tenth Annual Conference of the Construction History Society : Queen's College, University of Cambridge, 12-13 April 2023}, journal = {Studies in Construction History : the Proceedings of the Tenth Annual Conference of the Construction History Society : Queen's College, University of Cambridge, 12-13 April 2023}, editor = {Campbell, James}, publisher = {Construction History Society}, address = {Cambridge}, isbn = {978-0-9928751-9-0}, pages = {57 -- 74}, abstract = {The cathedrals and lavish secular buildings of the high medieval era bear witness to the level of skill with which heavy ashlars were hoisted and laid by the contemporary craftsmen. However, due to the lack of sources like treatises and naturalistic depictions we know comparably little about the cranes they used. To refine our knowledge of high medieval cranes this paper discusses their construction and technical capabilities based around preserved machines and finds examined with the methods of building archaeology.}, language = {en} } @misc{SimonYusubovAmirli, author = {Simon, Sylvio and Yusubov, Nizami and Amirli, Samir}, title = {Formation of Geometric Parameters of the Surfaces of Cylindrical Parts during Waterjet Cutting}, series = {Machine Building and Energy: New Concepts and Technologies (MBENCT)}, journal = {Machine Building and Energy: New Concepts and Technologies (MBENCT)}, editor = {Simon, Sylvio and Amirov, Fariz and Namazov, Subhan}, publisher = {Trans Tech Publication Ltd.}, address = {Baech}, isbn = {978-0364-0034-1}, pages = {59 -- 64}, abstract = {The article is devoted to the study of the technological process of water jet cutting of cylindrical parts on CNC machines. The results of experimental data on determining the accuracy of dimensional deviation, surface roughness, and taper of cylindrical parts depending on the circular milling of a water jet during water jet cutting are presented.}, language = {en} } @misc{KonlechnerKellerMartinetal., author = {Konlechner, Stefan and Keller, Arne and Martin, Alexander and G{\"u}ttel, Wolfgang and Fortwengel, Johann}, title = {Sequential leadership logics for coping with tensions in structurally ambidextrous units}, series = {Forschungspapier mit Vortrag bei der Konferenz 39th EGOS Colloquium 2023, 6.-8. Juli, Cagliari (Italien)}, journal = {Forschungspapier mit Vortrag bei der Konferenz 39th EGOS Colloquium 2023, 6.-8. Juli, Cagliari (Italien)}, pages = {40}, language = {en} } @misc{GaoLinZhangetal., author = {Gao, Yunlong and Lin, Tingting and Zhang, Yisong and Luo, Sizhe and Nie, Feiping}, title = {Robust principal component analysis based on discriminant information}, series = {IEEE Transactions on Knowledge and Data Engineering}, volume = {35}, journal = {IEEE Transactions on Knowledge and Data Engineering}, number = {2}, publisher = {IEEE}, issn = {1558-2191}, doi = {10.1109/TKDE.2021.3093447}, pages = {1991 -- 2003}, abstract = {Recently, several robust principal component analysis (RPCA) models were presented to enhance the robustness of PCA by exploiting the robust norms as their loss functions. But an important problem is that they have no ability to discriminate outliers from correct samples. To solve this problem, we propose a robust principal component analysis based on discriminant information (RPCA-DI). RPCA-DI disentangles the robust PCA with a two-step fashion: the identification and the processing of outliers. To identity outliers, a sample representation model based on entropy regularization is constructed to analyze the membership of data belonging to the principal component space(PC) and its orthogonal complement(OC), the discriminative information of data will be extracted based on measuring the differences of retained information on PC(or OC) of data. By this way, we can discriminate correct samples when we deal with outliers, which is more reasonable for robustness learning respective to previous works. In the noise processing step, in addition to considering the levels of noise, the resistance of the sample points to noise is also considered to prevent overfitting, thereby improving the generalization performance of RPCA-DI. Finally, an iterative algorithm is designed to solve the corresponding model. Compared with some state-of-art RPCA methods on artificial datasets, UCI datasets and face databases that verifies the effectiveness of our proposed algorithm.}, language = {en} } @misc{ZhangAalst, author = {Zhang, Yisong and Aalst, Wil van der}, title = {Explorative Process Discovery Using Activity Projections}, series = {International Conference on Applications and Theory of Petri Nets and Concurrency, PETRI NETS 2023}, journal = {International Conference on Applications and Theory of Petri Nets and Concurrency, PETRI NETS 2023}, publisher = {Springer, Cham}, isbn = {978-3-031-33619-5}, doi = {10.1007/978-3-031-33620-1_13}, pages = {229 -- 239}, abstract = {This paper presents a tool to Explore Process Discovery (EPD) results using activity projection. Our EPD-Tool aims at exploring quality changes after removing activities from an event log. The main idea is to create a projected event log for every non-empty subset of activities and apply process discovery and conformance checking on them. The tool has been implemented as a plugin in ProM. First, EPD-Tool uses a process discovery algorithm to discover Petri net models for each projected event log. Then, EPD-Tool uses a conformance checking technique to compute conformance measures for each projected event log and model pair (L, N), e.g., fitness, precision, and F1-score. Finally, a dendrogram is generated to visualize the relationship between each log-model pair, thus enabling the systematic exploration of the different models using the dendrogram to find the best-performing node, i.e., a best log-model pair. This method prioritizes activities and detects redundancy in the process, which contributes to process enhancement. Conversely, critical activities are uncovered to help to shorten the processing time or save the process cost. This paper presents the EPD-Tool implementation and some example results.}, language = {en} } @misc{PhielerDost, author = {Phieler, Ulrike and Dost, Florian}, title = {Does It Pay to Increase Public Messages in Nano-Influencer Campaigns? Investigating the Optimal Public Message Share for Sales and Return-On-Investment}, series = {2023 ISMS Marketing Science Conference Proceedings}, journal = {2023 ISMS Marketing Science Conference Proceedings}, pages = {3}, abstract = {Online influencer marketing has matured, and many managers now seek better performance with nano-influencers in seeding campaigns. Compared to macro-influencers, nano-influencers create more private (direct online or offline) brand messages that supposedly deliver more "persuasive punch". But such private messages lack the usual online tracking per message, forcing managers to ask nano-influencers for self-reports, or to estimate sales at a campaign level if they want to assess their own decisions. Therefore, little is known about how to set up effective nano-influencer campaigns: does it pay to increase the public message share in nano-influencer activity, in order to benefit from private and public influencer activity? Or does it defeat its purpose, diminishing nano-influencers' persuasiveness and total campaign results? This study analyses a unique campaign-level data set of various seeded marketing campaigns comprising the activity of 700,000 nano-influencers. We model the impact of nano-influencers' activity on incremental sales and return-on-investment (ROI) at the campaign level. To answer our questions, we include effects of public message share and optimal public message share and their interaction with activity; instrumenting both for identification, and controlling for campaign, marketing, and brand context. We find conditional optimal public message shares for both sales and ROI. The average campaign benefits most when increasing influencer activity (through design or incentives) at public message shares between 4\% and 5\%. This shows the importance of striking the right balance between nano-influencers' online and offline activity, and suggests a similar balance for combining nano- and macro-influencers in future campaign formats.}, language = {en} } @misc{PhielerDost, author = {Phieler, Ulrike and Dost, Florian}, title = {Does It Pay to Increase Public Messages in Nano-Influencer Campaigns? Investigating the Optimal Public Message Share for Sales and Return-On-Investment}, series = {2023 ISMS Marketing Science Conference Proceedings}, journal = {2023 ISMS Marketing Science Conference Proceedings}, publisher = {INFORMS}, pages = {3}, abstract = {Online influencer marketing has matured, and many managers now seek better performance with nano-influencers in seeding campaigns. Compared to macro-influencers, nano-influencers create more private (direct online or offline) brand messages that supposedly deliver more "persuasive punch". But such private messages lack the usual online tracking per message, forcing managers to ask nano-influencers for self-reports, or to estimate sales at a campaign level if they want to assess their own decisions. Therefore, little is known about how to set up effective nano-influencer campaigns: does it pay to increase the public message share in nano-influencer activity, in order to benefit from private and public influencer activity? Or does it defeat its purpose, diminishing nano-influencers' persuasiveness and total campaign results? This study analyses a unique campaign-level data set of various seeded marketing campaigns comprising the activity of 700,000 nano-influencers. We model the impact of nano-influencers' activity on incremental sales and return-on-investment (ROI) at the campaign level. To answer our questions, we include effects of public message share and optimal public message share and their interaction with activity; instrumenting both for identification, and controlling for campaign, marketing, and brand context. We find conditional optimal public message shares for both sales and ROI. The average campaign benefits most when increasing influencer activity (through design or incentives) at public message shares between 4\% and 5\%. This shows the importance of striking the right balance between nano� influencers' online and offline activity, and suggests a similar balance for combining nano- and macro-influencers in future campaign formats}, language = {en} } @misc{Korensky, author = {Korensky, Vladimir}, title = {Contribution of Europeans to the Further Development of Reinforced Concrete in the Russian Tsarist Empire}, series = {Studies in Construction History : the Proceedings of the Tenth Annual Conference of the Construction History Society : Queen's College, University of Cambridge, 12-13 April 2023}, journal = {Studies in Construction History : the Proceedings of the Tenth Annual Conference of the Construction History Society : Queen's College, University of Cambridge, 12-13 April 2023}, editor = {Campbell, James}, publisher = {Construction History Society}, address = {Cambridge}, isbn = {978-0-9928751-9-0}, pages = {411 -- 421}, abstract = {The introduction of early reinforced concrete by the European specialists in the Russian Empire can be divided into two development periods. Due to their intensive efforts, the new construction method was successfully introduced in constructions of public, residential and industrial buildings at the end of the 19th century using the well-known Monier and Hennebique systems. The application of the construction method during this stage of development ranged from single building elements to small-scale structures. At the beginning of the 20th century, the increasing adoption of the application of construction methods in all fields of construction by Russian specialists and the unstable political situation in the country led to the interruption of the activity of foreign specialists. After the political situation had stabilised and the country experienced a new wave of industrialisation, construction activity by Europeans was relaunched with impetus. Drawing on catalogues of the construction companies, on historical technical literature and on available archival documents, this paper names the important European specialists and describes their buildings constructed during this phase in the Russian Empire. Special attention is paid to the large scale skeletal structures.}, language = {en} } @misc{ReichsteinBruschDostetal., author = {Reichstein, Thomas and Brusch, Ines and Dost, Florian and Brusch, Michael}, title = {Maximizing Engagement Through Caption Optimization: Insights from Social Media Field Data}, series = {2023 ISMS Marketing Science Conference Proceedings}, journal = {2023 ISMS Marketing Science Conference Proceedings}, abstract = {Social media managers are constantly seeking ways to maximize engagement with their content. While prior research has shed light on strategies for creating engaging content, the impact of captions on engagement has been under-explored. Our study focuses specifically on the relationship between caption length and engagement in social media posts. Contrary to previous literature, we find that the relationship between caption length and engagement follows an inverted U-shape. Using field data from an omnichannel retailer (Facebook) and a travel influencer (Instagram), we determine the optimal caption length for maximizing engagement and present surprising results. Our results are robust for different model and identification specifications, indicating that captions are often too short, rather than too long, and that optimizing caption length in our case can increase engagement by up to 25\%. These findings have important implications for social media managers and influencers seeking to enhance the impact of their posts.}, language = {en} } @misc{HermannsUrbigBlocketal., author = {Hermanns, Thomas and Urbig, Diemo and Block, J{\"o}rn and M{\"u}hlfeld, Katrin}, title = {Economic adjustment strategies of self-employed individuals during essential crises: The case of complementary paid jobs}, series = {39th EGOS Colloquium. Organizing for the good life: Between legacy and imagination, University of Cagliari July 6-8, 2023, Cagliari, Italy}, journal = {39th EGOS Colloquium. Organizing for the good life: Between legacy and imagination, University of Cagliari July 6-8, 2023, Cagliari, Italy}, abstract = {Research on entrepreneurs combining their own start-ups with wage work—often referred to as hybrid or part-time entrepreneurship—has primarily focused on employees (temporarily) retaining their wage jobs while (gradually) transitioning into entrepreneurship. During crises, however, entrepreneurs seeking to ensure survival of their existing ventures may strive to supplement self-employment with entry into wage jobs. Specifically, we hypothesize that such crisis-coping may facilitate venture survival through two separate pathways, an income-portfolio-driven one and one geared towards business model testing. The latter effect is contingent upon the degree of uncertainty regarding the business model change. We test these hypotheses empirically against the backdrop of the Covid-19 crisis using a sample of more than 10.000 German self-employed individuals. The results largely support our hypotheses and overall offer interesting implications for both future research as well as policymakers seeking to support small businesses during crisis periods.}, language = {en} } @misc{StoeckmannKensbockUrbig, author = {St{\"o}ckmann, Christoph and Kensbock, Julia and Urbig, Diemo}, title = {Synthesizing a new conceptual and empirical understanding of ambidexterity and its effects on firm performance}, series = {26th Annual Interdisciplinary Conference on Entrepreneurship, Innovation and SMEs, 2023}, journal = {26th Annual Interdisciplinary Conference on Entrepreneurship, Innovation and SMEs, 2023}, abstract = {Ambidexterity is a wide-established and popular construct that promises to combine two seemingly opposing strategic actions—exploration and exploitation—for higher firm performance. Nevertheless, the (apparently peaceful) coexistence of two different conceptions of ambidexterity hampers a unified theoretical and empirical understanding in the field. This study introduces a new conceptual framework to study ambidexterity and its effects on firm performance. We propose that firms need to overcome two distinct types of trade-off—a trade-off in effects and a trade-off in implementing exploration and exploitation. If firms manage to be ambidextrous in effects and ambidextrous in implementing, they will achieve what we consider a higher-order synergetic ambidexterity. In addition to our theoretical framework, we provide an empirical illustration based on a commonality analysis. Our findings demonstrate how (a) independent effects of exploration and exploitation, (b) interaction effects of exploration and exploitation (representing ambidexterity in effects), and (c) shared effects of exploration and exploitation (representing ambidexterity in implementing) separately and jointly contribute to higher firm performance. We find that the highest effect on firm performance can be observed when firms are both ambidextrous in effects and ambidextrous in implementing.}, language = {en} } @misc{UrbigDostGeiger, author = {Urbig, Diemo and Dost, Florian and Geiger, Ingmar}, title = {Entrepreneurs misdiagnosing their ventures' innovativeness: The roles of causation and effectuation}, series = {26th Annual Interdisciplinary Conference on Entrepreneurship, Innovation and SMEs, 2023}, journal = {26th Annual Interdisciplinary Conference on Entrepreneurship, Innovation and SMEs, 2023}, abstract = {This text discusses the concept of misdiagnosis in entrepreneurial ventures, where managers' unrealistic optimism can lead to misaligned strategies and late pivots. The study explores the connection between misdiagnosis and decision logics (effectuation and causation) through motivated reasoning and beliefs. The researchers conducted a study with 266 ventures from innovative industries and measured misdiagnosis by comparing managers' judgments with external experts' assessments of venture innovativeness. The results show that causation logic positively influences misdiagnosis, but this effect is reduced when coupled with flexibility. The study highlights the importance of objective performance measures and suggests that motivated reasoning and beliefs explain the link between causation logic and misdiagnosis. Additionally, older and larger ventures with a prevalence of causation logic may experience more misdiagnosis and potential delays in innovation efforts. Flexibility is crucial for older ventures to remain innovative.}, language = {en} } @misc{KappeUrbigLengsfeld, author = {Kappe, Karina and Urbig, Diemo and Lengsfeld, Stephan}, title = {Not my business! The role of organizational culture in supporting employees with side businesses}, series = {26th Annual Interdisciplinary Conference on Entrepreneurship, Innovation and SMEs, 2023}, journal = {26th Annual Interdisciplinary Conference on Entrepreneurship, Innovation and SMEs, 2023}, abstract = {Organizations can benefit from their employees doing entrepreneurial side hustles through, e.g., empowerment or innovativeness, but do employers, as the most critical stakeholder for hybrid entrepreneurs, perceive and positively react to entrepreneurial side hustles? Research on the active role of the parental organization in the emergence and operation of entrepreneurial side activities is currently missing. Drawing on a large dataset with 855 managers, we explore the heterogeneity of organizations in responding to such employees. We place the organizational culture of the employers in the spotlight and examine its impact on managerial perceptions and their behavior in this context. We show that organizational characteristics such as flexibility or an internal focus lead to positive expectations of side hustles and claim that recognition is a relevant prerequisite to exploit arising opportunities or mitigate threats effectively. We fur-thermore show that next to indirect effects through outcome expectations, cultural characteris-tics also drive behavioral responses directly. For instance, focusing on flexibility leads to sup-portive behavior, while a strong focus on internal or external factors of an organization impedes supportive organizational behavior. We contribute to research on the emerging phenomenon of side hustles and push theory by revealing employer characteristics that lead to a more or less conducive environment for this type of entrepreneurs.}, language = {en} } @misc{MochkabadiKleinertUrbigetal., author = {Mochkabadi, Kazem and Kleinert, Simon and Urbig, Diemo and Volkmann, Christine}, title = {From distinctiveness to optimal distinctiveness: External endorsements, innovativeness and new venture funding}, series = {26th Annual Interdisciplinary Conference on Entrepreneurship, Innovation and SMEs, 2023}, journal = {26th Annual Interdisciplinary Conference on Entrepreneurship, Innovation and SMEs, 2023}, abstract = {To maximize their performance, new ventures should be optimally distinctive, that is, as differentiated from competitors as is legitimately possible. External endorsements, through affiliations with reputable third-parties, might alter the level of optimal distinctiveness for new ventures among different resource-providing audiences. To develop and test this prediction, the authors study new ventures with varying degrees of innovativeness that seek funding from return- and novelty-seeking resource providers. The former expect some distinctiveness but reject too little or too much (e.g., non- or radically innovative new ventures). External endorsements can buffer the legitimacy of these non-innovative and radically innovative ventures, but they lead to different performance implications. For non-innovative ventures, external endorsements function as a shield against low legitimacy, so they are less penalized for their lack of novelty. For radically innovative ventures, external endorsements function as a performance booster; they can become even optimally distinctive and outperform other distinctiveness configurations. In contrast, novelty-seeking audiences already have a higher tolerance for more innovative new ventures, so these effects are less pronounced among these resource providers. Four empirical studies, using observational data and experiments in equity and reward-based crowdfunding, provide strong support for this theory and account for several alternative explanations. In turn, this study sheds new light on the crucial, audience-specific function of external endorsements, namely, as a means to alter optimal distinctiveness levels.}, language = {en} } @misc{RoederUrbigStoeckmannetal., author = {R{\"o}der, Martin and Urbig, Diemo and St{\"o}ckmann, Christoph and B{\"o}nte, Werner and Procher, Vivien D.}, title = {There's no fox like an old fox: Dimensions of entrepreneurial orientation and venture closure}, series = {26th Annual Interdisciplinary Conference on Entrepreneurship, Innovation and SMEs, 2023}, journal = {26th Annual Interdisciplinary Conference on Entrepreneurship, Innovation and SMEs, 2023}, abstract = {Only a few scholars examined downsides of EO and suggest it may negatively affect survival. Previous research, which mainly focuses on mature companies, assumes that the relationship between EO and survival is constant. However, because firm characteristics and causal mechanisms change as young venture survive and grow into mature firms, the relationships between EO and survival could also change over time. We extend the EO literature by considering changing EO effects when venture grow into mature firms and by employing a multidimensional view on EO and identify isolating independent mechanisms for the influence of each dimension (i.e. innovativeness, proactiveness and risk-taking) on the survival of young ventures. While the nature of proactiveness on performance is rathe positive, risk-taking and innovativeness increases the variance of firm performance and thus the chances of failure. However, the latter can be separated according to whether the increase in variance occurs at a single point in time (risk-taking) or over time (innovation) and whether the survivors have more money or more innovations. For young firms, innovativeness and risk-taking inhibit survival, while proactiveness promotes it, so the dimensions have divergent effects. As a consequence of the attrition of young ventures, the associations of innovativeness and risk-taking reverse when they grow older. Our empirical analyses are based on panel data of 8,518 young firms.}, language = {en} } @misc{ZambranoCurcioUrbigBoenteetal., author = {Zambrano-Curcio, Andr{\´e}s Felipe and Urbig, Diemo and B{\"o}nte, Werner and Schmutzler, Jana}, title = {At the Risk of Loss: Experimental Evidence on the Discriminant Validity of Self-Reported Measures of Risk Preferences}, series = {SSRN eLibrary}, journal = {SSRN eLibrary}, issn = {1556-5068}, doi = {10.2139/ssrn.4371973}, pages = {1 -- 39}, abstract = {In recent years, there has been increasing use of experimentally validated self-reported items to measure individuals' risk preferences, specifically risk aversion. While previous research supports their convergent validity, we argue that self-reported risk preference measures capture a broad spectrum of additional constructs involved in risky decision-making, notably including loss aversion as a potential confound. In broader applications, such as observational studies, associations with other constructs enhance a measurement's ability to predict risk-taking behaviors across diverse natural environments, often arising from the interplay of different constructs better captured by comprehensive self-reported measures than by narrower, construct-specific incentivized measures. Conversely, in focused tests where each construct has unique behavioral implications, using broad self-reported measures as a replacement for construct-specific incentivized measurements can result in significant endogeneity issues. By analyzing three samples from two independent studies, we demonstrate that even after accounting for incentivized risk preference measures that remove latent construct associations and focus on measurement-related confounds, self-reported risk preferences maintain a substantial association with incentivized loss aversion measures, indicating that the measurement captures a mixture of both risk and loss aversion. We also observe that the strength of associations depends on whether individuals interpret risk-taking as accepting higher variances or higher losses. Based on this finding, we propose a simple procedure that utilizes this individual heterogeneity in the confounding effect's strength to enhance the robustness of conclusions drawn from analyses of self-reported risk preference measures}, language = {en} } @misc{KansokDuscheWachsWettsteinetal., author = {Kansok-Dusche, Julia and Wachs, Sebastian and Wettstein, Alexander and Bilz, Ludwig}, title = {Hatespeech und Mobbing in der Schule: {\"U}berschneidungen und Unterschiede hinsichtlich der Determinanten und der beteiligten Sch{\"u}lerinnen und Sch{\"u}ler}, series = {Symposium Cancel Culture, Hate Speech, Diskriminierung und Verschw{\"o}rungstheorien in der Schule: Jahrestagung AEPF 2023 vom 13.-15.9.2023 in Potsdam}, journal = {Symposium Cancel Culture, Hate Speech, Diskriminierung und Verschw{\"o}rungstheorien in der Schule: Jahrestagung AEPF 2023 vom 13.-15.9.2023 in Potsdam}, pages = {10}, abstract = {Hintergrund. Hatespeech (dt. Hassrede) ist weltweit ein Problem, das auch unter Jugendlichen verbreitet ist und p{\"a}dagogisch ausgerichtete Pr{\"a}ventions- und Interventionsans{\"a}tze erfordert (Castellanos et al., 2023; United Nations, 2021). Hatespeech wird hier als intentional herabw{\"u}rdigende {\"A}ußerung {\"u}ber Personen verstanden, die auf zugeschriebene Merkmale sozialer Gruppen Bezug nimmt (Kansok-Dusche et al., 2022). Da Hatespeech mit negativen Konsequenzen f{\"u}r Betroffene und die Gesellschaft einhergeht, ist die Schule ein wichtiger Ort zur Hatespeech-Pr{\"a}vention. Forscher:innen thematisieren mit Blick auf Hatespeech bei Kindern und Jugendlichen die {\"U}berlappung von Hatespeech und Mobbing und fordern mehr Studien dazu (z.B. Bedrosova et al., 2022; Fulantelli et al., 2022). Eine {\"U}bersichtsarbeit verweist auf moderate Korrelationen zwischen dem Aus{\"u}ben von Online-Hatespeech und Cyberbullying (Kansok-Dusche et al., 2022). Studien zur {\"U}berlappung der Ph{\"a}nomene im Offline-Modus gibt es bisher nicht. Eine weitere {\"U}bersichtsarbeit zeigt, dass das Aus{\"u}ben von Cyberbullying und Online-Hatespeech durch {\"a}hnliche Faktoren determiniert ist (Fulantelli et al., 2022). Allerdings basiert diese Erkenntnis haupts{\"a}chlich auf Studien, die diese Faktoren entweder f{\"u}r Cyberbullying oder f{\"u}r Online-Hatespeech untersuchten. Zur Divergenz bzw. Konvergenz von Determinanten beider Ph{\"a}nomene im Offline-Modus gibt es bisher keine Studien. Fragestellung und Ziele. Die Forschungsfrage der Studie richtet sich auf {\"A}hnlichkeiten und Unterschiede zwischen Hatespeech und Mobbing. Sie nutzt drei analytische Perspektiven: Zun{\"a}chst untersuchen wir variablenorientiert die Korrelationen zwischen dem Aus{\"u}ben von Mobbing und Hatespeech im Online- und Offline-Modus (Ziel 1). Dann folgen wir einer personenzentrierten Perspektive und ermitteln, inwieweit es {\"U}berschneidungen bei den involvierten Sch{\"u}lergruppen gibt (Ziel 2). Schließlich interessieren uns Gemeinsamkeiten und Unterschiede in der Relevanz verschiedener Determinanten: wir betrachten die soziale Perspektiven{\"u}bernahme, das schulische Zugeh{\"o}rigkeitsempfinden, die Soziale Dominanzorientierung und das Klassenklima (Ziel 3). Methoden. Die Analysen basieren auf Selbsteinsch{\"a}tzungen von 3.260 Sch{\"u}ler:innen der Jahrgangsstufen 7 bis 9 aus 42 Schulen in Deutschland und der Schweiz (51\% weiblich, 41.4\% mit Migrationsstatus). Die Sch{\"u}ler:innen beantworteten freiwillig und anonym einen Fragebogen (12/2020 - 04/2021). Mit Einzelitems wurden die H{\"a}ufigkeiten f{\"u}r das Aus{\"u}ben von Mobbing und Hatespeech, separat f{\"u}r den On- und Offline-Modus erfasst. Weitere Skalen dienten der Erfassung der sozialen Perspektiven{\"u}bernahme (Jurkowski \& H{\"a}nze, 2014, 3 Items, α = .72), der sozialen Dominanzorientierung (Klocke, 2012, 8 Items, α = .80), des schulischen Zugeh{\"o}rigkeitsempfindens (OECD, 2017; 6 Items α = .83), und des Klassenklimas (Currie et al., 2014, 3 Items, α = .78). Die Analysen erfolgen separat f{\"u}r den On- und Offline-Modus mittels Korrelationsanalysen (Ziel 1), Kontingenztabellen (Ziel 2) und regressionsanalytische Mehrebenenmodelle (Ziel 3). Ergebnisse und Diskussion. Die Analysen werden gerade durchgef{\"u}hrt und sollen auf der Konferenz vorgestellt werden. Die Ergebnisse k{\"o}nnen Forscher:innen und PraktikerIinnen bei der Entscheidung unterst{\"u}tzen, ob Hatespeech und Mobbing unter Jugendlichen als miteinander verkn{\"u}pfte oder getrennte Formen der Aggression erforscht und adressiert werden sollten. Trotz Limitationen (z.B. Selbsteinsch{\"a}tzungen, Querschnittsdaten) k{\"o}nnen die Ergebnisse Ausgangspunkt f{\"u}r Pr{\"a}ventions- und Interventionsmaßnahmen sein, die Kinder und Jugendliche davor sch{\"u}tzen, T{\"a}ter:in und/oder Opfer von Hatespeech, Mobbing oder beidem zu werden.}, language = {de} } @misc{KleinUrbig, author = {Klein, Sarah and Urbig, Diemo}, title = {Should I stay or should I go? Die Rolle von Hoffnung in Jobwechseldynamiken}, series = {Krisen meistern, Ressourcen aufbauen, Nachhaltigkeit st{\"a}rken. Abstracts zur 26. Fachtagung der Gesellschaft f{\"u}r angewandte Wirtschaftspsychologie (GWPs)}, journal = {Krisen meistern, Ressourcen aufbauen, Nachhaltigkeit st{\"a}rken. Abstracts zur 26. Fachtagung der Gesellschaft f{\"u}r angewandte Wirtschaftspsychologie (GWPs)}, editor = {Sachse, Katharina and Kurzenh{\"a}user-Carstens, Stephanie}, publisher = {Pabst Science Publishers}, address = {Lengerich/Westfalen}, isbn = {978-3-95853-834-4}, pages = {S. 33}, abstract = {Theoretischer Hintergrund: Hoffnung wirkt als motivationaler Mechanismus auf Handlungsintentionen in Krisensituationen und Situationen unter Unsicherheit (Krafft \& Walker, 2018). Obwohl sich Hoffnung in den vergangenen Jahren als wichtige psychologische Ressource f{\"u}r pers{\"o}nliche Leistung und Zielerreichung in der Forschung etabliert hat, gibt es wenige Studien zum Einfluss auf berufsbezogene Entscheidungen. Diese zeigen jedoch Beziehungen zu wichtigen berufsbezogenen Variablen wie Jobzufriedenheit und Jobwechselabsicht (Reichard et al., 2013). Fragestellung/Hypothesen: {\"U}ber bekannte Effekte hinaus untersucht diese Studie den Einfluss von dispositioneller Hoffnung auf Jobwechseldynamiken. Wir betrachten Hoffnung als kontextunspezifischen, mehrdimensionalen Faktor, bestehend aus internaler selbstbezogener Hoffnung (Snyder, 2002) und ex ternaler Hoffnung auf einflussreiche Dritte sowie Zufall oder Schicksal (Bernardo, 2010). Wir hypothetisieren, dass insbesondere internale Hoffnung Jobwechselprozesse beeinflusst und den negativen Zusammenhang von Jobzufriedenheit und Jobwechselabsicht verst{\"a}rkend moderiert. Methodik/Ergebnisse: Die Hypothesen werden mittels Regressionsanalysen an einer Stichprobe von N=826 Berufst{\"a}tigen gepr{\"u}ft. Internale Hoffnung korreliert negativ mit aktuellen Jobwechselabsichten, unter Kontrolle f{\"u}r Jobzufriedenheit wird dieser Zusammenhang positiv. Wir best{\"a}tigen den verst{\"a}rkenden Effekt internaler Hoffnung auf den negativen Zusammenhang von Jobzufriedenheit und Jobwechselabsicht. Die Effekte sind robust, wenn f{\"u}r dispositionellen Optimismus als Alternativerkl{\"a}rung kontrolliert wird. Internale Hoffnung ist zudem positiv mit fr{\"u}heren Jobwechseln sowie aktueller Jobzufriedenheit assoziiert. Diskussion/Implikationen: Unsere Studie leistet einen Beitrag zur Hoffnungsforschung im betrieblichen Kontext und belegt den Einfluss von Hoffnung auf Jobwechselprozesse. Eine divergente Wirkung von Hoffnung wird durch die Verst{\"a}rkung von Jobwechselabsichten unter Jobunzufriedenheit gezeigt, bei gleichzeitiger Assoziation mit Jobzufriedenheit. Hoffnung sollte als personalpsychologischer Wirkmechanismus st{\"a}rker in den Mittelpunkt innerbetrieblicher Maßnahmen ger{\"u}ckt werden, um diesen gezielt im Personalmanagement einzusetzen.}, language = {en} } @misc{NakosBeirow, author = {Nakos, Alex and Beirow, Bernd}, title = {On the Influence of Installation on the Forced Response of Radial Turbine Wheels}, series = {Proceedings of Global Power and Propulsion Society, GPPS Hongkong, October 16 - 19, 2023}, journal = {Proceedings of Global Power and Propulsion Society, GPPS Hongkong, October 16 - 19, 2023}, issn = {2504-4400}, doi = {10.33737/gpps23-tc-138}, pages = {10}, abstract = {Radial turbine wheels are commonly designed as integrally bladed rotors featuring extremely low structural damping in comparison to separate designs of blades and disk. Consequently, they are more prone to vibration. Moreover, random blade mistuning due to unavoidable inaccuracies in manufacture or material inhomogeneities can severely increase the maximum forced blade vibration amplitude compared to the tuned counterpart. Unfortunately, this response magnification may worsen in case of small damping. Since modes exhibiting blade dominated vibration are usually considered vulnerable in this regard, the influence of disk and shaft and its mounting conditions seems to be negligible. In this paper, reduced order models are employed in order to simulate the forced response of a radial turbine wheel. Experimental modal analyses have been carried out to provide realistic damping ratios considering both the single turbine wheel hardware as well as the full rotor mounted in a turbocharger test rig. Test runs are conducted and non-intrusive blade-tip-timing technology provides measurement data to validate the simulation models. Contrary to the original presumption, it is shown that additional structural damping contributed by assembling can significantly influence the forced response even though the focus is on blade dominated vibration.}, language = {en} } @misc{KarnapkeWalther, author = {Karnapke, Reinhardt and Walther, Karsten}, title = {Internet of Things and Real Internet of Things}, series = {20. GI/ITG KuVS Fachgespr{\"a}ch Sensornetze (FGSN 2023)}, journal = {20. GI/ITG KuVS Fachgespr{\"a}ch Sensornetze (FGSN 2023)}, editor = {Piotrowski, Krzysztof}, doi = {10.26127/BTUOpen-6637}, url = {http://nbn-resolving.de/https://nbn-resolving.org/urn:nbn:de:kobv:co1-opus4-66374}, pages = {2 -- 4}, abstract = {Sensor networks have come a long way since their first inception 30 years ago. In this paper we look at the results achieved and the areas that still need research from an industry perspective.}, language = {en} } @misc{Kaluza, author = {Kaluza, Bennet}, title = {BLE Periodic Advertising as an Alternative to BLE Mesh and Scatternets for Multihop Communication}, series = {20. GI/ITG KuVS Fachgespr{\"a}ch Sensornetze (FGSN 2023)}, journal = {20. GI/ITG KuVS Fachgespr{\"a}ch Sensornetze (FGSN 2023)}, doi = {10.26127/BTUOpen-6637}, pages = {10 -- 11}, abstract = {Waldw{\"a}chter 5G is a project about preventing damages to forests, for example by fire. For this case, sensors connected in a Bluetooth Low Energy (BLE) multi-hop environment are deployed to detect abnormalities. BLE is a widely spread wireless communication technology used for low power devices, such as smart home appliances or sensors. This paper presents two approaches for BLE multi-hop communication, BLE Mesh as a flooding based network primarily used for non-power-limited devices and BLE scatternets as a lose collective term for a lot of interconnected smaller networks. It then introduces the idea of a third possible option, a network topology based on a BLE 5.0 feature called Periodic Advertising (PA). The idea of an approach to PA meshes is explained and the advantages presented.}, language = {en} } @misc{RottaMykytyn, author = {Rotta, Randolf and Mykytyn, Pavlo}, title = {Secure Multi-hop Telemetry Broadcasts for UAV Swarm Communication}, series = {20. GI/ITG KuVS Fachgespr{\"a}ch Sensornetze (FGSN 2023)}, journal = {20. GI/ITG KuVS Fachgespr{\"a}ch Sensornetze (FGSN 2023)}, doi = {10.48550/arXiv.2401.11915}, pages = {13 -- 14}, abstract = {Unmanned Aerial Vehicles (UAVs) are evolving as adaptable platforms for a wide range of applications such as precise inspections, emergency response, and remote sensing. Autonomous UAV swarms require efficient and stable communication during deployment for a successful mission execution. For instance, the periodic exchange of telemetry data between all swarm members provides the foundation for formation flight and collision avoidance. However, due to the mobility of the vehicles and instability of wireless transmissions, maintaining a secure and reliable all-to-all communication remains challenging. This paper investigates encrypted and authenticated multi-hop broadcast communication based on the transmission of custom IEEE 802.11 Wi-Fi data frames.}, language = {en} } @misc{RakhiGiriGuentheretal., author = {Rakhi, Rakhi and Giri, Binod Raj and G{\"u}nther, Vivien and Mauss, Fabian}, title = {Investigation dry reforming of methane over nickel using a one-dimensional model}, series = {PAMM}, volume = {23}, journal = {PAMM}, number = {4}, doi = {10.1002/pamm.202300266}, pages = {8}, abstract = {In the field of catalysis, dry reforming, that is, methane reforming with CO2, is in the focus due to growing environmental concerns about oil depletion and global warming with a desire to produce synthesis gas. However, this process can lead to the formation of carbon, which can cause catalyst deactivation, especially at industrial conditions. Nevertheless, the key to develop a more coke-resistant catalyst is a better comprehension of the reforming process at a molecular level. Regardless of all the investigations available in literature, the detailed path for the conversion of methane to syngas and carbon remains a controversial issue. Another problem in setting up a reaction mechanism is the difficulty to define the thermodynamic data for intermediate surface species and this leads to the development of thermodynamic consistent surface reaction mechanisms in literature where the thermodynamic data are not used to calculate the rate coefficients of the reverse reactions. Rather the Arrhenius parameters for the forward as well as backward reactions are explicitly given in the reaction mechanism to establish thermodynamic equilibrium. In this investigation, a kinetically consistent detailed surface reaction mechanism is developed which consists of 26 reversible reactions with the help of a one-dimensional model, LOGEcat. Our previous work constructs the basis of the present investigation. Further, a detailed sensitivity analysis of reversible reactions and reaction pathways is performed to understand the mechanism better. The mechanism is validated for dry reforming of methane over nickel catalyst, however, it can also be used for other processes, such as, steam reforming and partial oxidation. The mechanism is tested by comparing the simulation results with the literature experiments and simulations in a wide range of temperature. The new developed kinetically consistent surface reaction mechanism is able to accurately express the dry reforming of methane over the nickel catalyst for complete range of temperature and also provide a useful insight into the key rate determining steps.}, language = {en} } @misc{RakhiGiriGuentheretal., author = {Rakhi, Rakhi and Giri, Binod Raj and G{\"u}nther, Vivien and Mauss, Fabian}, title = {Insight into the thermodynamic model for reforming of methane over nickel catalyst}, series = {Proceedings of the 64th International Conference of Scandinavian Simulation Society, SIMS 2023 V{\"a}ster{\aa}s, Sweden, September 25-28, 2023}, journal = {Proceedings of the 64th International Conference of Scandinavian Simulation Society, SIMS 2023 V{\"a}ster{\aa}s, Sweden, September 25-28, 2023}, doi = {10.3384/ecp200025}, pages = {192 -- 197}, abstract = {The reforming of light hydrocarbons to produce synthesis gas, H2 and CO, is an important intermediate for manufacturing valuable basic chemicals and synthesis fuels. In order to understand these reforming processes better, elementary step reaction mechanisms are developed. In the available literature, the surface reaction mechanisms are usually achieved with the help of reaction kinetic parameters without using the thermochemistry of the species referred to kinetic models due to the unavailability of the thermochemistry of the intermediate species involved in the multi-step reaction mechanism. In this work, investigations are made to obtain the thermochemistry of the intermediate species to establish thermodynamic equilibrium in order to develop a thermodynamic model for steam reforming of methane over nickel. The thermochemistry of the surface bound species is taken from different sources available in the literature and after that a detailed sensitivity analysis is performed to match the results with experiments. The simulation set up is adapted from the literature experiments given in [1]. The results produced with the one-dimensional tool using the thermodynamic model developed in the present investigation consisting of 21 reversible reactions are compared with the kinetic scheme with 42 irreversible reactions from reference simulation along with their experimental results. Both the models show some major differences in the reaction pathways which provides a useful insight into the key rate determining steps and needs further investigations.}, language = {en} } @misc{HerdDoerreWackerleetal., author = {Herd, Rainer and D{\"o}rre, Bert and Wackerle, R. and Holst, Jonathan}, title = {Leben in einer Jurte - aerogeophysikalische Untersuchungen mit dem Multi-Sensor-Erkundungssystem D-MTUC in der Mongolei}, series = {83. Jahrestagung der Deutschen Geophysikalischen Gesellschaft in Bremen, 05.-09. M{\"a}rz 2023}, journal = {83. Jahrestagung der Deutschen Geophysikalischen Gesellschaft in Bremen, 05.-09. M{\"a}rz 2023}, address = {Bremen}, issn = {0344­-7251}, pages = {152 -- 152}, abstract = {Aus verschiedenen Gr{\"u}nden entwickelte der Lehrstuhl Rohstoff­ und Ressourcenmanagement der Brandenburgischen Technischen Universit{\"a}t Cottbus mit internationalen Partnern ein „low noise" Multi­Sensor-Erkundungssystem auf Basis eines Ultraleichtflugzeugs. Die geowissenschaftliche Instrumentierung des Systems umfasst ein CsI­y­Spektrometer, 2 K­Magnetometer, einen VLF­EM­Empf{\"a}nger und die M{\"o}glichkeit zur Installation weiterer Sensoren, Details siehe bei Herd und Holst (2015). Im Rahmen der „Deutsch­Mongolischen Rohstoffpartnerschaft" wurde das System 2018 f{\"u}r Rohstofferkundungen per LKW in die Mongolei verschickt. Partner vor Ort sind die Deutsch­Mongolische Hochschule f{\"u}r Rohstoffe und Technologie und die Mineral Resource and Petroleum Authority of Mongolia. Bevor die wissenschaftliche Mission starten konnte, mussten in intensiven Gespr{\"a}chen mit der mongolischen Zivilluftfahrtbeh{\"o}rde (MCAA) administrative Schwierigkeiten ausger{\"a}umt werden. Anschließend musste das Forscherteam diverse Herausforderungen bew{\"a}ltigen: raue Wind­ und Wetterbedingungen, starke Thermik, begrenzte Verf{\"u}gbarkeit von 98­Oktan­Kraftstoff, verunreinigter Kraftstoff, der zu vor{\"u}bergehenden Motorausf{\"a}llen f{\"u}hrte, Schotterpisten, die die Propellerbl{\"a}tter beeintr{\"a}chtigten, usw. Dennoch konnten verschiedene Gebiete in der zentralen W{\"u}ste Gobi, im Hangai­Gebirge und im Großraum Ulan Bator untersucht und akzeptable Ergebnisse erzielt werden. Insgesamt wurden 4600 Linienkilometer bzw. 750 km² beflogen. Die Linienabst{\"a}nde betrugen 100 m und 250 m, die Flugh{\"o}he betrug 100 m, trotz teilweise intensiver Topographie. Die durchschnittliche Fluggeschwindigkeit w{\"a}hrend der Vermessung betrug 120 km/h mit einer Abtastrate von 10 Hz f{\"u}r die Magnetometer und 1 Hz f{\"u}r das Spektrometer. Da die Mongolei in Bezug auf zivile Luftfahrt noch recht jungfr{\"a}ulich ist, wurde hier Pionierarbeit geleistet. F{\"u}r weitere {\"a}hnliche Missionen ist das Eis gebrochen. Das Verbundwerkstoff­Flugzeug sowie die Sensoren erwiesen sich als sehr robust und zuverl{\"a}ssig. Der Treibstoffverbrauch lag bei 10­15 l/h MOGAS 98, was zu niedrigen Kosten f{\"u}hrte. Es zeigte sich, dass Vermessungsfl{\"u}ge mit ultraleichten Systemen in der Mongolei m{\"o}glich sind, aber aufgrund der erw{\"a}hnten Bedingungen sorgf{\"a}ltig geplant werden m{\"u}ssen. Die Erfahrungen und Eindr{\"u}cke dieser ungew{\"o}hnlichen wissenschaftlichen Mission werden vorgestellt}, language = {de} } @misc{RoemerbeimGrabenHuberLiebletal., author = {R{\"o}mer, Ronald and beim Graben, Peter and Huber-Liebl, Markus and Wolff, Matthias}, title = {(Pre-)linguistic Problem Solving based on Dynamic Semantics}, series = {14th IEEE International Conference on Cognitive Infocommunications - CogInfoCom 2023, September 22-23, Budapest, Hungary}, journal = {14th IEEE International Conference on Cognitive Infocommunications - CogInfoCom 2023, September 22-23, Budapest, Hungary}, isbn = {979-8-3503-2565-2}, issn = {2473-5671}, doi = {10.1109/CogInfoCom59411.2023.10397487}, pages = {147 -- 152}, language = {en} } @misc{JohanssonEngkvistChehreghanietal., author = {Johansson, Simon Viet and Engkvist, Ola and Chehreghani, Morteza Haghir and Schliep, Alexander}, title = {Diverse Data Expansion with Semi-Supervised k-Determinantal Point Processes}, series = {2023 IEEE International Conference on Big Data (BigData), 15-18 December 2023, Sorrento, Italy}, journal = {2023 IEEE International Conference on Big Data (BigData), 15-18 December 2023, Sorrento, Italy}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {979-83-503-2445-7}, doi = {10.1109/BigData59044.2023.10386642}, pages = {5260 -- 5265}, abstract = {Determinantal point processes (DPPs) have become prominent in data summarization and recommender system tasks for their ability to simultaneously model diversity as well as relevance. In practical applications, k-Determinantal point processes (k-DPPs) are used to yield a selection of k items from a set of size N that are the most representative of the set. In this paper, we study a special case of the diverse subset selection problem where a fixed set GO is already given as a forced recommendation and the task is to determine the remainder of the recommendation G1. The standard k-DPP optimization objectives here can suggest items that are close to optimal when considering only items in G1, but are arbitrarily close to items in G0, i.e., they might not be sufficiently diverse w.r.t. G0. We explore a semi-supervised k-DPP objective that simultaneously considers G0 and G1 and compares the difference between the two recommendations. We demonstrate our findings using multiple examples where the diverse subset selection problem with forced recommendation is important in practice.}, language = {en} } @misc{DruzynskivonBoetticher, author = {Druzynski von Boetticher, Alexandra}, title = {Dachwerksentwurf f{\"u}r drei Ausbaustufen - Die Seitenschiffd{\"a}cher des Berner M{\"u}nsters}, series = {Materialgerecht konstruiert!?! Tagungsband der F{\"u}nften Jahrestagung vom 10. bis 11. Juni 2021 in Z{\"u}rich, Schriftenreihe der Gesellschaft f{\"u}r Bautechnikgeschichte}, journal = {Materialgerecht konstruiert!?! Tagungsband der F{\"u}nften Jahrestagung vom 10. bis 11. Juni 2021 in Z{\"u}rich, Schriftenreihe der Gesellschaft f{\"u}r Bautechnikgeschichte}, editor = {Rauhut, Christoph and Weber, Christiane and Bastgen, Michael and Sieder, Mike and Kuban, Sabine}, publisher = {Imhof}, address = {Petersberg}, isbn = {978-3-7319-1253-8}, pages = {261 -- 274}, language = {de} } @misc{Herd, author = {Herd, Rainer}, title = {Five years of raw material exploration with the ultra-light airborne system D-MTUC in Mongolia - a review}, series = {2nd International Conference "Resources and Technology" (RESAT 2023) at the German-Mongolian Institute for Resources and Technology (GMIT)}, journal = {2nd International Conference "Resources and Technology" (RESAT 2023) at the German-Mongolian Institute for Resources and Technology (GMIT)}, pages = {17 -- 18}, abstract = {Within the frame of the 'German-Mongolian Raw Material Partnership', the multi-sensor airborne investigation system D-MTUC was transported 2018 to Mongolia for raw material exploration in cooperation with the German-Mongolian insititute for Resources and Technology (GMIT) and the Mineral Resource and Petroleum Authority for Mongolia. The geoscientific instrumentation of the system comprehends a Csl-y-spectrometer of MEDUSA, Netherlands, 2 K-magnetometer of GEM, Canada, a VLF-EM-receiver of RMS, Canada and a data acquisitation and control system of GeoDuster, RSA with the opinion of further sensor installations, for details see Herd and Holst (2015). The sensor configuration enables the system to operate at low speed and low altitude for mineral exploration, geological mapping, detection of freshwater resources and brine and different enviromental monitoring missions.}, language = {en} } @misc{SasakarosSchafferusWirsumetal., author = {Sasakaros, Marios and Schafferus, Markus and Wirsum, Manfred and Zobel, Arthur and Vogt, Damian and Nakos, Alex and Beirow, Bernd}, title = {Experimental Investigation of Synchronous Flow Induced Blade Vibrations on a Radial Turbine - Part 2: Influence of Different Inlet Guide Vane Configurations}, series = {Proceedings of ASME Turbo Expo 2023, Boston, Massachusetts, June 26-30, 2023, Volume 11, A. Aerodynamics excitation and damping, bearing and seal dynamics}, journal = {Proceedings of ASME Turbo Expo 2023, Boston, Massachusetts, June 26-30, 2023, Volume 11, A. Aerodynamics excitation and damping, bearing and seal dynamics}, publisher = {ASME}, address = {New York}, isbn = {978-0-7918-8705-9}, doi = {10.1115/GT2023-102243}, pages = {15}, abstract = {The occurrence of blade vibrations in radial turbines leads to limit cycle oscillations, which in time increase the risk of component failure due to high cycle fatigue. In this context, the precise determination of the resonance operating points and the estimation of the vibration magnitudes are essential for an accurate assessment of the service life of the turbocharger components. In radial turbines forced blade vibrations are primarily flow induced. These vibrations are produced by the non-uniform flow field in the circumferential direction which acts on the blades as a cyclic pressure fluctuation. Previous studies have identified the inlet guide vane (IGV) and the spiral turbine housing as the primary sources of the non-uniform flow field. In the present study a thorough experimental investigation of the synchronous blade vibrations of a radial turbine is performed. First, the blade vibration modes were measured experimentally and calculated numerically for the determination of the speed ranges that need to be examined. Subsequently, the vibrations were captured with two redundant measurement systems during real turbocharger operation. Strain gauges were applied on certain blades while eight optical sensors were distributed on the circumference of the turbine shroud for the measurement of the blades tips deflection through a commercial tip-timing system. In the first part, the blade vibrations caused by the "nominal" IGV are presented. Part 2 analyses the changes of the blade vibrations due to the application of two different IGVs. The first IGV has the same number of vanes as the "nominal" IGV. Nevertheless, it generates additional low engine order excitations by intentionally varying the distance between the vanes. Next, an IGV with a higher number of vanes is employed for the excitation at higher frequencies and thus of higher blade modes. Contrary to expectations, certain synchronous vibrations can be measured in the experiments of all IGVs. These cannot be attributed to the spiral turbine casing.}, language = {en} } @misc{SchafferusSasakarosWirsumetal., author = {Schafferus, Markus and Sasakaros, Marios and Wirsum, Manfred and Zobel, Arthur and Vogt, Damian and Nakos, Alex and Beirow, Bernd}, title = {Experimental Investigation of Synchronous Flow Induced Blade Vibrations on a Radial Turbine - Part 1: Nominal Inlet Guide Vane}, series = {Proceedings of ASME Turbo Expo 2023, Boston, Massachusetts, June 26-30, 2023, Volume 11, A. Aerodynamics excitation and damping, bearing and seal dynamics}, journal = {Proceedings of ASME Turbo Expo 2023, Boston, Massachusetts, June 26-30, 2023, Volume 11, A. Aerodynamics excitation and damping, bearing and seal dynamics}, publisher = {ASME}, address = {New York}, isbn = {978-0-7918-8705-9}, doi = {10.1115/GT2023-103037}, pages = {13}, abstract = {The service life of today's turbochargers is limited among other things by the mechanical load caused by blade vibrations. In this context, the precise determination of the resonance operating points and the estimation of the vibration magnitudes are essential for an accurate assessment of the service life of the turbocharger components. Forced blade vibrations in radial turbines are primarily flow induced. Flow induced blade vibrations are caused by the nonuniform flow field in the circumferential direction which acts on the blades as a cyclic pressure fluctuation. Previous studies identified the inlet guide vane (IGV) as well as the spiral turbine housing as the primary sources of the non-uniform flow field. In the present study a thorough experimental investigation of the synchronous blade vibrations of a radial turbine is performed. A detailed description of the experimental setup is given. In this setup the vibrations are captured with two redundant measurement systems during real turbocharger operation. Strain gauges, applied on certain blades, as well as optical tip-timing sensors distributed on the circumference of the turbine shroud are used. The advantages of the combined usage of these two measuring systems are shown in the paper. Initially, the blade vibration modes are determined experimentally in stand still tests and numerically calculated through FEM models. This served for the creation of a Campbell diagram, which determined the speed ranges that are examined. The mistuning, which is not taken into account in the numerics, is therefore determined via the experiment. In addition, the experimental results are compared with those of numerics and the frequencies from standstill test. The first part of this two-part paper is focused on the vibrations caused by the "nominal" IGV. This "nominal" IGV has twice the number of blades compared to the rotor. Part 2 will analyze the changes of the blade vibrations due to the application of two different IGVs.}, language = {en} } @misc{ZobelFuhrerVogtetal., author = {Zobel, Arthur and Fuhrer, Christopher and Vogt, Damian and Nakos, Alex and Beirow, Bernd and Blessing, Alexander and Zippack, Carolin}, title = {On the Influence of Bearing Modeling Details on the Dynamical System Effects of a Mid-Size Turbocharger Rotor}, series = {Proceedings of ASME Turbo Expo 2023, Boston, Massachusetts, June 26-30, 2023, Volume 11, A. Aerodynamics excitation and damping, bearing and seal dynamics}, journal = {Proceedings of ASME Turbo Expo 2023, Boston, Massachusetts, June 26-30, 2023, Volume 11, A. Aerodynamics excitation and damping, bearing and seal dynamics}, publisher = {ASME}, address = {New York}, isbn = {978-0-7918-8705-9}, doi = {10.1115/GT2023-102098}, pages = {11}, abstract = {The investigation of the excitation of turbocharger rotors to quantify the High-Cycle-Fatigue (HCF) risk is still a demanding task nowadays. The common way to investigate such phenomena is to look either at the turbine or the compressor rotor in an isolated manner. This approach gives mostly reliable results, if the investigated excitation pattern is stemming from the up- or downstream parts in the machine. However, there is a lack of studies on the existence of responses, which may exist due to the coupling between compressor and turbine. With the increase of computational capabilities and the improvement of FE tools, it is possible to create a full rotor model featuring the compressor and the turbine wheel as well as the bearings to investigate the dynamical behavior of the full rotor at different resonances. To carry out such an investigation, both wheels and the shaft are modeled. The axial, as well as the radial bearings, are modelled realistically by suitable elements and values. Due to the asymmetry of damping and stiffness properties, the resulting system matrices are asymmetrical as well. The eigenfrequencies and mode shapes of such a system can be obtained in a reasonable time by carrying out a modal analysis using the QR damp eigensolver in Ansys APDL. The present paper will show the differences in dynamical system effects of a mid-size turbocharger with different shaft support conditions. For this purpose, the FE simulation with the full rotor and fixed support at the radial bearing position, which is comparable to the isolated rotor consideration, will be compared to the model featuring the detailed bearing modeling with stiffness and damping values originating from the OEM. Besides the detailed process of modeling the bearings, the mutual influence of both rotor wheels at certain eigenfrequencies is analyzed. This allows to conclude on the level of detailing needed to ensure that dynamical system effects are properly accounted.}, language = {en} } @misc{KabinLangendoerferDyka, author = {Kabin, Ievgen and Langend{\"o}rfer, Peter and Dyka, Zoya}, title = {Vulnerability of Atomic Patterns to Simple SCA}, series = {19th IEEE East-West Design \& Test Symposium (EWDTS 2023), (2023)}, journal = {19th IEEE East-West Design \& Test Symposium (EWDTS 2023), (2023)}, isbn = {979-8-3503-1484-7}, issn = {2472-761X}, doi = {10.1109/EWDTS59469.2023.10297074}, pages = {4}, abstract = {In this work we discuss the vulnerability of atomic pattern algorithms for elliptic curve point multiplication against simple side-channel analysis attacks using our own implementation as an example. One of the assumptions, on which the atomicity principle is based, is the indistinguishability of operations with different registers, i.e. storing of the data into two different registers cannot be distinguished if their old and new data values are the same. But before the data can be stored in a register/block, this register/block has to be addressed for storing the data. Different registers/blocks have different addresses. The key-dependent addressing of registers/blocks is an inherent feature of the binary kP algorithms and allows to reveal the key k. In our work we demonstrated it. This means that the main assumption, that addressing of different registers/blocks is an indistinguishable operation, may no longer be applied when realizing kP implementations, at least not for hardware implementations.}, language = {en} } @misc{AlsabbaghKimLangendoerfer, author = {Alsabbagh, Wael and Kim, Chaerin and Langend{\"o}rfer, Peter}, title = {No Attacks Are Available: Securing the OpenPLC and Related Systems}, series = {8th GI/ACM Workshop on Industrial Automation and Control Systems (IACS WS 2023), 2085 (2023)}, journal = {8th GI/ACM Workshop on Industrial Automation and Control Systems (IACS WS 2023), 2085 (2023)}, doi = {10.13140/RG.2.2.24570.47043}, pages = {12}, abstract = {The use of Programmable Logic Controllers (PLCs) expands in industrial domains, which makes ensuring the security of Industrial Control Systems (ICSs) become paramount. The OpenPLC project, the first open-source initiative, provides flexible and cost-effective PLC solutions to build up affordable test-beds, as well as conduct experiments and academic researches. This project has wildly grown in the last few years, thus it is essential to address the most emerging security challenges it encounters. This paper introduces a new OpenPLC architecture, called OpenPLC Aqua, provided with a set of security solutions designed specifically to overcome the vulnerabilities that the current OpenPLC versions are prone to. The new OpenPLC architecture includes four security features: 1) user credentials encryption, securing the Webserver, Whitelisting and secure SSL/TLS communication channel. The OpenPLC Aqua software was tested against several attack scenarios, that were feasible against the old OpenPLC versions. Our experimental results showed our enhanced OpenPLC software is secure and resistant against several attack scenarios e.g., authentication, injection, Man-in-the-Middle and replay attacks. The OpenPLC Aqua is publicly available and a proof of concept demo is also published with this paper.}, language = {en} } @misc{SigourouKabinLangendoerferetal., author = {Sigourou, Alkistis and Kabin, Ievgen and Langend{\"o}rfer, Peter and Sklavos, Nicolas and Dyka, Zoya}, title = {Successful Simple Side Channel Analysis: Vulnerability of an Atomic Pattern kP Algorithm Implemented with a Constant Time Crypto Library to Simple Electromagnetic Analysis Attacks}, series = {12th Mediterranean Conference on Embedded Computing (MECO 2023), 167 (2023)}, journal = {12th Mediterranean Conference on Embedded Computing (MECO 2023), 167 (2023)}, isbn = {979-8-3503-2291-0}, issn = {2637-9511}, doi = {10.1109/MECO58584.2023.10154940}, pages = {6}, language = {en} } @misc{KabinDykaLangendoerfer, author = {Kabin, Ievgen and Dyka, Zoya and Langend{\"o}rfer, Peter}, title = {Randomized Addressing Countermeasures are Inefficient against Address-Bit SCA}, series = {IEEE International Conference on Cyber Security and Resilience (CSR 2023), 580 (2023)}, journal = {IEEE International Conference on Cyber Security and Resilience (CSR 2023), 580 (2023)}, isbn = {979-8-3503-1170-9}, doi = {10.1109/CSR57506.2023.10224968}, pages = {6}, language = {en} } @misc{AlsabbaghKimLangendoerfer, author = {Alsabbagh, Wael and Kim, Chaerin and Langend{\"o}rfer, Peter}, title = {Good Night, and Good Luck: A Control Logic Injection Attack on OpenPLC}, series = {Proc. 49th Annual Conference of the IEEE Industrial Electronics Society (IECON 2023), (2023)}, journal = {Proc. 49th Annual Conference of the IEEE Industrial Electronics Society (IECON 2023), (2023)}, doi = {10.13140/RG.2.2.32913.20321}, pages = {8}, language = {en} } @misc{SchmidWinkler, author = {Schmid, Stefan and Winkler, Herwig}, title = {Empirical Findings on the Need of Industrial Production Management Systems in the Context of Enhanced Digitalization}, series = {2023 IEEE International Conference on Industrial Engineering and Engineering Management (IEEM)}, journal = {2023 IEEE International Conference on Industrial Engineering and Engineering Management (IEEM)}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {979-8-3503-2315-3}, doi = {10.1109/IEEM58616.2023.10406474}, pages = {1406 -- 1410}, abstract = {Since the framework conditions of manufacturing companies change dynamically, production control must react to this and be adaptive and dynamically designed. Our article addresses the need of industrial production management systems in the course of enhanced digitization. The aim is to examine the extent to which traditional systems for controlling and optimizing production systems have been supplemented by Industry 4.0 concepts. In the course of the scarcity of resources and the shortage of labor, the human factor is once again coming to the fore. Against this background, the interaction between users / humans and artificial intelligence applications will be the main focus. The result should give an indicator how this connection must be considered in the future and what should artificial intelligence do in the context of production control. The findings will be the basis for future considerations of a smart production management system, which can be used for decision support as well as for auto-control.}, language = {en} } @misc{FoersterLangendoerferHinze, author = {F{\"o}rster, Benjamin and Langend{\"o}rfer, Peter and Hinze, Thomas}, title = {Novel Approach to a Plant Inspired Distributed Security Scheme for Wireless Sensor Networks}, series = {12th Mediterranean Conference on Embedded Computing (MECO), Budva, Montenegro, 2023}, journal = {12th Mediterranean Conference on Embedded Computing (MECO), Budva, Montenegro, 2023}, isbn = {979-8-3503-2291-0}, issn = {2637-9511}, doi = {10.1109/MECO58584.2023.10154949}, pages = {6}, abstract = {Energy efficiency is a key factor for the longevity of wireless sensor networks (WSNs). Most representatives of the plants have evolved to be highly energy-efficient in their survival strategies, despite their limited resources. Plants have to deal with a variety of threats originating from different herbivores and microbial pathogens while handling a number of abiotic stress factors. For plants and WSNs, different defence mechanisms impose different fitness costs and therefore the costs and benefits have to be well-balanced. This way, plants are able to not only conquer a large variety of different attacks but also handle several different simultaneous attacks adequately. To react early and adapt to upcoming threats, plants within a network are capable of signalling each other within a certain distance about ongoing attacks. The biological strategies of plants in terms of signalling and defence, as well as their energy and resource limitations, share significant similarities with WSNs. This study aims to explore these similarities and demonstrates the correspondence between the biological concepts and WSNs. Additionally, we present a novel approach to enhancing security in WSNs through a cooperative distributed security scheme inspired by key factors of plant defence mechanisms, with the goal of reducing the energy constraints and maximising the longevity of the network.}, language = {en} } @misc{AlsabbaghLangendoerfer, author = {Alsabbagh, Wael and Langend{\"o}rfer, Peter}, title = {You Are What You Attack: Breaking the Cryptographically-Protected S7 Protocol}, series = {19th International Conference on Factory Communication Systems (WFCS), (2023)}, journal = {19th International Conference on Factory Communication Systems (WFCS), (2023)}, publisher = {IEEE}, isbn = {978-1-6654-6432-1}, issn = {2835-8414}, doi = {10.1109/WFCS57264.2023.10144251}, pages = {8}, abstract = {S7 protocol defines an appropriate format for exchanging messages between SIMATIC S7 PLCs and their corresponding engineering software i.e., TIA Portal. Recently, Siemens has provided its newer PLC models and their proprietary S7 protocols with a very developed and sophisticated integrity check mechanism to protect them from various exploits e.g., replay attacks. This paper addresses exactly this point, and investigates the security of the most developed integrity check mechanism that the newest S7CommPlus protocol version implements. Our results showed that the latest S7 PLC models as well as their related protocols are still vulnerable. We found that adversaries can manipulate two hashes that play a significant role in generating keys and bytes for the encryption processes implemented in the S7CommPlus protocol. This allows to reproduce S7 packets and conduct several attacks that eventually impact the operation of the target PLC and the entire physical process it controls. To validate our findings, we test all the attack scenarios presented in this work on a cryptographically protected S7 PLC from the 1500 family which uses the S7CommPlusV3 protocol.}, language = {en} } @misc{FoersterLangendoerferHinze, author = {F{\"o}rster, Benjamin and Langend{\"o}rfer, Peter and Hinze, Thomas}, title = {Determining Distributions of Security Means for Wireless Sensor Networks based on the Model of a Neighbourhood Watch}, series = {arXiv}, journal = {arXiv}, doi = {10.48550/arXiv.2212.09050}, pages = {24}, abstract = {Neighbourhood watch is a concept that allows a community to distribute a complex security task in between all members. Members of the community carry out individual security tasks to contribute to the overall security of it. It reduces the workload of a particular individual while securing all members and allowing them to carry out a multitude of security tasks. Wireless sensor networks (WSNs) are composed of resource-constraint independent battery driven computers as nodes communicating wirelessly. Security in WSNs is essential. Without sufficient security, an attacker is able to eavesdrop the communication, tamper monitoring results or deny critical nodes providing their service in a way to cut off larger network parts. The resource-constraint nature of sensor nodes prevents them from running full-fledged security protocols. Instead, it is necessary to assess the most significant security threats and implement specialised protocols. A neighbourhood-watch inspired distributed security scheme for WSNs has been introduced by Langend\"orfer. Its goal is to increase the variety of attacks a WSN can fend off. A framework of such complexity has to be designed in multiple steps. Here, we introduce an approach to determine distributions of security means on large-scale static homogeneous WSNs. Therefore, we model WSNs as undirected graphs in which two nodes connected iff they are in transmission range. The framework aims to partition the graph into \$n\$ distinct security means resulting in the targeted distribution. The underlying problems turn out to be NP hard and we attempt to solve them using linear programs (LPs). To evaluate the computability of the LPs, we generate large numbers of random {\lambda}-precision unit disk graphs (UDGs) as representation of WSNs. For this purpose, we introduce a novel {\lambda}-precision UDG generator to model WSNs with a minimal distance in between nodes.}, language = {en} } @misc{AlsabbaghAmogbonjayeUrregoetal., author = {Alsabbagh, Wael and Amogbonjaye, Samuel and Urrego, Diego and Langend{\"o}rfer, Peter}, title = {A Stealthy False Command Injection Attack on Modbus based SCADA Systems}, series = {20th Consumer Communications \& Networking Conference (CCNC), (2023)}, journal = {20th Consumer Communications \& Networking Conference (CCNC), (2023)}, isbn = {978-1-6654-9734-3}, issn = {2331-9860}, doi = {10.1109/CCNC51644.2023.10059804}, pages = {9}, abstract = {Modbus is a widely-used industrial protocol in Supervisory Control and Data Acquisition (SCADA) systems for different purposes such as controlling remote devices, monitoring physical processes, data acquisition, etc. Unfortunately, such a protocol lacks security means i.e., authentication, integrity, and confidentiality. This has exposed industrial plants using the Modbus protocol and made them attractive to malicious adversaries who could perform various kinds of cyber-attacks causing significant consequences as Stuxnet showed. In this paper, we exploit the insecurity of the Modbus protocol and perform a stealthy false command injection scenario concealing our injection from the SCADA operator. Our attack approach is comprised of two main phases: 1) Pre-attack phase (offline) where an attacker sniffs, collects and stores sufficient valid request-response pairs in a database, 2) Attack phase (online) where the attacker performs false command injection and conceals his injection by replaying a valid response from his database upon each request sent from the HMI user. Such a scenario is quite severe and might cause disastrous damages in SCADA systems and critical infrastructures if it is successfully implemented by malicious adversaries. Finally, we suggest some appropriate mitigation solutions to prevent such a serious threat.}, language = {en} } @misc{Ijioma, author = {Ijioma, Uche Dickson}, title = {Assessing quality and health risks in drinking water sources in Aba, Nigeria}, series = {International Water Association Conference on Water \& Wastewater Management with Special on Developing Countries}, journal = {International Water Association Conference on Water \& Wastewater Management with Special on Developing Countries}, publisher = {Murdoch University Perth, Western Australia \& International Water Association (IWA)}, address = {Murdoch}, pages = {27 -- 27}, abstract = {The poor implementation of urban practices and weak policy enforcement are factors worsening the quality of natural drinking water sources in most urban areas of developing countries. A mixed approach guided by the water safety plan framework was employed. This involved an empirical study carried out among residents to identify the origin of drinking water sources and associated hazards linked to poor environmental practices. Laboratory investigations (physicochemical and chemical- 14 indicators, as well as biological - 2 bacteriological indicator organisms) were used to assess the health risks in selected samples of natural (groundwater, Aba River water, rainwater) and secondary (beverages, packaged water, and piped water) drinking sources in Aba, southeast Nigeria. A concise review of relevant environmental policies and laws was conducted to determine the control measures in place to protect the drinking water sources The results of the study revealed that groundwater is the origin of drinking water sources, the prevailing drinking water facility types are improved sources (i.e., 50 \% tube-wells, 48 \% secondary drinking sources, and 2 \% treated piped water), 76 \% of respondents do not pretreat before drinking and some urban practices that harm the quality of water were identified in the area. The chemical risk assessment showed that the mean values of the major and trace substances in the drinking water sources were within the standard limits recommended by the WHO. However, the bacteriological results revealed health risks in samples of natural (17 \%) and secondary (14 \%) drinking sources, which tested positive for either E. Coli or/and Total Coliform bacteria. It was found that existing control environmental instruments were inefficient due to overlapping duties of implementing government agencies, corruption, and lack of political will to do the things that protect the drinking water sources. The research concludes that deteriorating spatial chemical changes and bacteriological contaminations found in the area were caused by poor environmental practices. To prevent this degree of health risks in drinking water sources, relevant authorities should develop a safe drinking water abstraction plan that protects the groundwater, and more power devolved to local governments to enforce environmental instruments that protect the water sources in the area. Again, the regulatory agencies should ensure that only safe secondary drinking products are sold to consumers.}, language = {en} } @misc{AksanSureshJaniketal., author = {Aksan, Fachrizal and Suresh, Vishnu and Janik, Przemysław and Leonowicz, Zbigniew and Pfeiffer, Klaus}, title = {Prediction of regional PV power generation based on LSTM-CNN}, series = {Proceedings 2023 Asia Meeting on Environment and Electrical Engineering (EEE-AM), Hanoi (Vietnam)}, journal = {Proceedings 2023 Asia Meeting on Environment and Electrical Engineering (EEE-AM), Hanoi (Vietnam)}, isbn = {979-8-3503-8106-1}, doi = {10.1109/EEE-AM58328.2023.10395132}, pages = {6}, language = {en} } @misc{MarkowskiAbendrothLapushynskaetal., author = {Markowski, Jens and Abendroth, Christian and Lapushynska, Alina and Lohse, Anja}, title = {Experiences from the commissioning of a bioleaching plant for the recovery of gold from printed circuit boards}, series = {Biomining´23 - 11th International Symposium on Biomining}, journal = {Biomining´23 - 11th International Symposium on Biomining}, publisher = {Mining Engineering}, address = {Falmouth (UK)}, abstract = {Production waste from the manufacture of PCB often contains gold-containing contact-strips, whereby the gold content is < 1 \%. Recycling of these gold coatings with conventional melting processes is technically hardly, since the carrier materials often contain mechanical reinforcements and flame retardants in addition to thermosetting plastics. With mechanical recycling, gold losses of 50\% are possible. Therefore, a bioleaching plant for the recovery of gold and copper as preliminary stage for the smelting process has been in operation on m\&k´s site since May 2022. The bioleaching is realized with iron and sulfur oxidizing bacteria, e.g. Leptospirilum ferrooxidans. The apparatus consists of a 400 litres-leaching bioreactor and peripheral equipment (fermenter, cementation, filters). The plant can process up to 10 kg of gold-containing PCB waste per batch, while simultaneously regenerating a second batch of bioleaching fluid. The process can recover up to 450 mg goldtinsel and 25 g copperpowder per Kilogramm input.}, language = {en} } @misc{JeeningaMachadoCucuzzellaetal., author = {Jeeninga, Mark and Machado, Juan Eduardo and Cucuzzella, Michele and Como, Giacomo and Scherpen, Jacquelien}, title = {On the existence and uniqueness of steady state solutions of a class of dynamic hydraulic networks via actuator placement}, series = {62nd IEEE Conference on Decision and Control (CDC), 2023}, journal = {62nd IEEE Conference on Decision and Control (CDC), 2023}, isbn = {979-8-3503-0124-3}, issn = {2576-2370}, doi = {10.1109/CDC49753.2023.10384050}, pages = {6}, language = {en} } @misc{MendozaAvilaEfimovMercadoUribeetal., author = {Mendoza-Avila, Jesus and Efimov, Denis and Mercado-Uribe, Angel and Schiffer, Johannes}, title = {Design of Controls for Boundedness of Trajectories of Multistable State Periodic Systems}, series = {62nd IEEE Conference on Decision and Control (CDC), 2023}, journal = {62nd IEEE Conference on Decision and Control (CDC), 2023}, isbn = {979-8-3503-0124-3}, issn = {2576-2370}, doi = {10.1109/CDC49753.2023.10383528}, pages = {6}, language = {en} } @misc{MercadoUribeMendozaAvilaEfimovetal., author = {Mercado-Uribe, Angel and Mendoza-{\´A}vila, Jes{\´u}s and Efimov, Denis and Schiffer, Johannes}, title = {A Control Leonov Function Guaranteeing Global ISS of Two Coupled Synchronverters}, series = {62nd IEEE Conference on Decision and Control (CDC), 2023}, journal = {62nd IEEE Conference on Decision and Control (CDC), 2023}, isbn = {979-8-3503-0124-3}, issn = {2576-2370}, doi = {10.1109/CDC49753.2023.10383811}, pages = {6}, language = {en} } @misc{ZuritaBustamanteRuedaEscobedoSchiffer, author = {Zurita-Bustamante, Erik W. and Rueda-Escobedo, Juan G. and Schiffer, Johannes}, title = {Passivity-Based Conditions for Asymptotic Stability of Speed Control for Three-Phase and Dual Three-Phase Permanent Magnet Synchronous Motors}, series = {62nd IEEE Conference on Decision and Control (CDC), 2023}, journal = {62nd IEEE Conference on Decision and Control (CDC), 2023}, isbn = {979-8-3503-0124-3}, issn = {2576-2370}, doi = {10.1109/CDC49753.2023.10383817}, pages = {6}, language = {en} } @misc{JaramilloCajicaMercadoUribeSchiffer, author = {Jaramillo-Cajica, Ismael and Mercado-Uribe, Angel and Schiffer, Johannes}, title = {Coordinated Control of Load Tap Changer Transformers for Voltage Regulation and Voltage Hunting Prevention: A Switched Systems Approach}, series = {62nd IEEE Conference on Decision and Control (CDC), 2023}, journal = {62nd IEEE Conference on Decision and Control (CDC), 2023}, isbn = {979-8-3503-0124-3}, issn = {2576-2370}, doi = {10.1109/CDC49753.2023.10383763}, pages = {6}, language = {en} } @misc{MahmoodHuebnerReichenbach, author = {Mahmood, Safdar and H{\"u}bner, Michael and Reichenbach, Marc}, title = {A Design-Space Exploration Framework for Application-Specific Machine Learning Targeting Reconfigurable Computing}, series = {Applied Reconfigurable Computing. Architectures, Tools, and Applications, 19th International Symposium, ARC 2023, Cottbus, Germany, September 27-29, 2023}, journal = {Applied Reconfigurable Computing. Architectures, Tools, and Applications, 19th International Symposium, ARC 2023, Cottbus, Germany, September 27-29, 2023}, editor = {Palumbo, Francesca and Keramidas, Georgios and Voros, Nikolaos and Diniz, Pedro C.}, publisher = {Springer}, address = {Cham}, isbn = {978-3-031-42921-7}, doi = {10.1007/978-3-031-42921-7_27}, pages = {371 -- 374}, language = {en} } @misc{SchmidtFuegenschuh, author = {Schmidt, Johannes and F{\"u}genschuh, Armin}, title = {Temperature-Based Trajectory Planning for Surfaces in Wire- Arc Additive Manufacturing}, series = {Operations Research Proceedings 2022 : Selected Papers of the Annual International Conference of the German Operations Research Society (GOR), Karlsruhe, Germany, September 6-9, 2022}, journal = {Operations Research Proceedings 2022 : Selected Papers of the Annual International Conference of the German Operations Research Society (GOR), Karlsruhe, Germany, September 6-9, 2022}, editor = {Grothe, Oliver and Nickel, Stefan and Rebennack, Steffen and Stein, Oliver}, publisher = {Springer}, address = {Heidelberg}, isbn = {978-3-031-24906-8}, pages = {539 -- 545}, language = {en} } @misc{WenAugelWangetal., author = {Wen, Hanying and Augel, Lion and Wang, Wenjuan and Knobbe, Jens}, title = {Characterization of AlSiCu/TiN/p-Si Schottky Contacts with Nanophotonic Structures for Near-infrared Photodetectors}, series = {2023 46th International Spring Seminar on Electronics Technology (ISSE) : 10-14 May 2023 : conference location: Timișoara, Romania}, journal = {2023 46th International Spring Seminar on Electronics Technology (ISSE) : 10-14 May 2023 : conference location: Timișoara, Romania}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {979-8-3503-3485-2}, doi = {10.1109/ISSE57496.2023.10168510}, pages = {1 -- 5}, abstract = {Schottky photodetectors based on internal photoemission have the potential of an adjustable detection range in the near-infrared range and Si compatible technology integration. The external quantum efficiency of Schottky photodetectors can be improved using nanophotonic structures, which enhance the absorption of the device. However, the electrical properties of Schottky photodetectors deviate under an altered metal-semiconductor interface topography. We characterize a common layer system for metal contacts consisting of a TiN interstitial layer between the p-Si wafer and the AlSiCu metallization. By varying the thickness of the TiN we discuss how homogeneity of the sputtered layers influence device properties with different interface topographies. Through electrical wafer-level characterization, the characteristics of the Schottky contact are evaluated and compared to the ideal physical modelling.}, language = {en} } @misc{PitonakKillat, author = {Pitonak, Pavol and Killat, Dirk}, title = {Dynamic delta sigma ADC with variable clock on 65 nm CMOS}, series = {2023 Kleinheubach Conference, September 26-28, 2023, Miltenberg, Germany}, journal = {2023 Kleinheubach Conference, September 26-28, 2023, Miltenberg, Germany}, publisher = {IEEE}, address = {Piscataway}, isbn = {978-3-948571-08-5}, pages = {1 -- 3}, language = {en} } @misc{VenkateshaKillat, author = {Venkatesha, Shishira S. and Killat, Dirk}, title = {A fully differential 3-stage CMOS op-amp for high-speed sampling applications}, series = {2023 Kleinheubach Conference, September 26 - 28, 2023, Miltenberg, Germany}, journal = {2023 Kleinheubach Conference, September 26 - 28, 2023, Miltenberg, Germany}, publisher = {IEEE}, address = {Piscataway}, isbn = {978-3-948571-08-5}, pages = {1 -- 4}, language = {en} } @misc{KillatKoeppelUlmannetal., author = {Killat, Dirk and K{\"o}ppel, Sven and Ulmann, Bernd and Wetzel, Lucas}, title = {Solving Partial Differential Equations with Monte Carlo / Random Walk on an Analog-Digital Hybrid Computer}, series = {Tagungsband MikroSystemTechnik Kongress 2023, Dresden, 23. - 25. Oktober 2023}, journal = {Tagungsband MikroSystemTechnik Kongress 2023, Dresden, 23. - 25. Oktober 2023}, publisher = {VDE Verlag}, address = {Berlin}, isbn = {978-3-8007-6203-3}, pages = {556 -- 564}, language = {en} } @misc{SuawaFogouHalbingerJongmannsetal., author = {Suawa Fogou, Priscile and Halbinger, Anja and Jongmanns, Marcel and Reichenbach, Marc}, title = {Noise-Robust Machine Learning Models for Predictive Maintenance Applications}, series = {IEEE Sensors Journal}, volume = {23}, journal = {IEEE Sensors Journal}, number = {13}, issn = {1558-1748}, doi = {10.1109/JSEN.2023.3273458}, pages = {15081 -- 15092}, abstract = {Predictive maintenance of equipment requires a set of data collected through sensors, from which models will learn behaviors that will allow the automatic detection or prediction of these behaviors. The objective is to anticipate unexpected situations such as sudden equipment stoppages. Industries are noisy environments due to production lines that involve a series of components. As a result, the data will always be obstructed by noise. Noise-robust predictive maintenance models, which include ensemble and deep learning models with and without data fusion, are proposed to enhance the monitoring of industrial equipment. The work reported in this article is based on two components, a milling tool, and a motor, with sound, vibration, and ultrasound data collected in real experiments. Four main tasks were performed, namely the construction of the datasets, the training of the monitoring models without adding artificial noise to the data, the evaluation of the robustness of the previously trained models by injecting several levels of noise into the test data, and the optimization of the models by a proposed noisy training approach. The results show that the models maintain their performances at over 95\% accuracy despite adding noise in the test phase. These performances decrease by only 2\% at a considerable noise level of 15-dB signal-to-noise ratio (SNR). The noisy training method proved to be an optimal solution for improving the noise robustness and accuracy of convolutional deep learning models, whose performance regression of 2\% went from a noise level of 28 to 15 dB like the other models.}, language = {en} } @misc{AugelWenKnobbe, author = {Augel, Lion and Wen, Hanying and Knobbe, Jens}, title = {TiN-Si Schottky Diodes for SWIR Detection}, series = {Tagungsband MikroSystemTechnik Kongress 2023, Dresden, 23. - 25. Oktober 2023}, journal = {Tagungsband MikroSystemTechnik Kongress 2023, Dresden, 23. - 25. Oktober 2023}, publisher = {VDE Verlag}, address = {Berlin}, isbn = {978-3-8007-6204-0}, pages = {30 -- 34}, language = {en} } @misc{MonsalveGuaracaoKaiserSchenk, author = {Monsalve Guaracao, Jorge Mario and Kaiser, Bert and Schenk, Harald}, title = {Design of Micromachined Ultrasonic Transducers for Variability with the Sample-Average Approximation Method}, series = {Tagungsband MikroSystemTechnik Kongress 2023, Dresden, 23. - 25. Oktober 2023}, journal = {Tagungsband MikroSystemTechnik Kongress 2023, Dresden, 23. - 25. Oktober 2023}, publisher = {VDE Verlag}, address = {Berlin}, isbn = {978-3-8007-6204-0}, pages = {S. 639}, language = {en} } @misc{BartschGopeKavunetal., author = {Bartsch, Witali and Gope, Prosanta and Kavun, Elif and Millwood, Owen and Panchenko, Andriy and Pasikhani, Aryan and Polian, Ilia}, title = {Design Rationale for Symbiotically Secure Key Management Systems in IoT and Beyond}, series = {Proceedings of the 9th International Conference on Information Systems Security and Privacy ICISSP - Volume 1}, journal = {Proceedings of the 9th International Conference on Information Systems Security and Privacy ICISSP - Volume 1}, publisher = {SciTePress}, isbn = {978-989-758-624-8}, issn = {2184-4356}, doi = {10.5220/0011726900003405}, pages = {583 -- 591}, abstract = {The overwhelmingly widespread use of Internet of Things (IoT) in different application domains brought not only benefits, but, alas, security concerns as a result of the increased attack surface and vectors. One of the most critical mechanisms in IoT infrastructure is key management. This paper reflects on the problems and challenges of existing key management systems, starting with the discussion of a recent real-world attack. We identify and elaborate on the drawbacks of security primitives based purely on physical variations and - after highlighting the problems of such systems - continue on to deduce an effective and cost-efficient key management solution for IoT systems extending the symbiotic security approach in a previous work. The symbiotic architecture combines software, firmware, and hardware resources for secure IoT while avoiding the traditional scheme of static key storage and generating entropy for key material on-the-fly via a combination of a Physical Unclonable Func tion (PUF) and pseudo-random bits pre-populated in firmware.}, language = {en} } @misc{KellerMartinKonlechneretal., author = {Keller, Arne and Martin, Alexander and Konlechner, Stefan and G{\"u}ttel, Wolfgang and Fortwengel, Johann}, title = {Evolving Tensions Across Different Stages of Ambidexterity}, series = {Academy of Management Proceedings}, volume = {2023}, journal = {Academy of Management Proceedings}, number = {1}, issn = {0065-0668}, doi = {10.5465/AMPROC.2023.17856abstract}, language = {en} } @misc{LehnigerAftowiczSchoelzeletal., author = {Lehniger, Kai and Aftowicz, Marcin and Sch{\"o}lzel, Mario and Langend{\"o}rfer, Peter}, title = {Coarse-Grained Control Flow Integrity Check for Processors with Sliding Register Windows}, series = {12th Mediterranean Conference on Embedded Computing (MECO)}, journal = {12th Mediterranean Conference on Embedded Computing (MECO)}, isbn = {979-8-3503-2291-0}, issn = {2637-9511}, doi = {10.1109/MECO58584.2023.10154928}, pages = {7}, language = {en} } @misc{MykytynBrzozowskiDykaetal., author = {Mykytyn, Pavlo and Brzozowski, Marcin and Dyka, Zoya and Langend{\"o}rfer, Peter}, title = {GPS-Spoofing Attack Detection Mechanism for UAV Swarms}, series = {12th Mediterranean Conference on Embedded Computing (MECO)}, journal = {12th Mediterranean Conference on Embedded Computing (MECO)}, isbn = {979-8-3503-2290-3}, issn = {2637-9511}, doi = {10.1109/MECO58584.2023.10154998}, pages = {8}, language = {en} } @misc{FischerMaunderBilzetal., author = {Fischer, Saskia M. and Maunder, Rachel and Bilz, Ludwig and Bauman, Sheri and Scheithauer, Herbert}, title = {Teachers' Responses to Incidents of Bullying among Students: Study Protocol and Preliminary Results of a Systematic Review on How Teachers React to and Manage Bullying Situations}, series = {27th Workshop on Aggression}, journal = {27th Workshop on Aggression}, doi = {10.17605/OSF.IO/QCGDX}, language = {en} } @misc{HainesMosahebMuelleretal., author = {Haines, Thomas and Mosaheb, Rafieh and M{\"u}ller, Johannes and Pryvalov, Ivan}, title = {SoK: Secure E-Voting with Everlasting Privacy.}, series = {Thomas Haines, Rafieh Mosaheb, Johannes M{\"u}ller, Ivan Pryvalov. "SoK: Secure E-Voting with Everlasting Privacy." In Proceedings on Privacy Enhancing Technologies (PoPETS), 2023.}, journal = {Thomas Haines, Rafieh Mosaheb, Johannes M{\"u}ller, Ivan Pryvalov. "SoK: Secure E-Voting with Everlasting Privacy." In Proceedings on Privacy Enhancing Technologies (PoPETS), 2023.}, doi = {10.56553/popets-2023-0017}, pages = {279 -- 293}, abstract = {Vote privacy is a fundamental right, which needs to be protected not only during an election, or for a limited time afterwards, but for the foreseeable future. Numerous electronic voting (e-voting) protocols have been proposed to address this challenge, striving for everlasting privacy. This property guarantees that even computationally unbounded adversaries cannot break privacy of past elections. The broad interest in secure e-voting with everlasting privacy has spawned a large variety of protocols over the last three decades. These protocols differ in many aspects, in particular the precise security properties they aim for, the threat scenarios they consider, and the privacy-preserving techniques they employ. Unfortunately, these differences are often opaque, making analysis and comparison cumbersome. In order to overcome this non-transparent state of affairs, we systematically analyze all e-voting protocols designed to provide everlasting privacy. First, we illustrate the relations and dependencies between all these different protocols. Next, we analyze in depth which protocols do provide secure and efficient approaches to e-voting with everlasting privacy under realistic assumptions, and which ones do not. Eventually, based on our extensive and detailed treatment, we identify which research problems in this field have already been solved, and which ones are still open. Altogether, our work offers a well - founded reference point for conducting research on secure e - voting with everlasting privacy as well as for future - proofing privacy in real - world electronic elections.}, language = {en} } @misc{GambittaBeirowKlauke, author = {Gambitta, Marco and Beirow, Bernd and Klauke, Thomas}, title = {Investigation of Rear Blisk Drum Dynamics Under Consideration of Multi-Stage Coupling}, series = {Proceedings of ASME Turbo Expo 2023, Boston, Massachusetts, June 26-30, 2023}, journal = {Proceedings of ASME Turbo Expo 2023, Boston, Massachusetts, June 26-30, 2023}, isbn = {978-0-7918-8705-9}, doi = {10.1115/GT2023-103756}, abstract = {The analysis of the structural dynamics of multistage cyclic structures as linked components is required to model the interstage coupling. In turbomachinery, this can result in a collaboration between different compressor or turbine stages. This paper investigates the coupling between two rear drum blade integrated disk stages of an axial compressor to support the mechanical design process. Considering the vibration modeshapes of a multistage system, different components may co-participate in the dynamics. For this reason, a criteria to identify the modes affected by the coupling and to quantify this coupling is defined. This allows to distinguish between modes with inter-stage coupling, requiring the multistage system for their description, and uncoupled modes, involving a single stage. In addition, it is of interest to research methods to reduce the impact of the coupling on the vibrating system without drastically altering the geometry of the components. The vibration analyses of a two-stage compressor generalized geometry, representative of a compressor rear drum blisk, is presented as a study case. The use of a reducing method allows to describe the behavior of the nominal multistage system with a computationally efficient technique, enabling a parametric analysis of the stages' coupling. The investigation considers the effect of a set of geometrical and mechanical parameters on the dynamics, identifying the driving parameters of the coupled vibration characteristics.}, language = {en} } @misc{SchweissguthParzyjeglaDanielisetal., author = {Schweissguth, Eike and Parzyjegla, Helge and Danielis, Peter and M{\"u}hl, Gero and Timmermann, Dirk and Mehner, Stefan and Hohlfeld, Oliver and Hellmanns, David and Falk, Jonathan}, title = {TSN Scheduler Benchmarking}, series = {2023 IEEE 19th International Conference on Factory Communication Systems (WFCS)}, journal = {2023 IEEE 19th International Conference on Factory Communication Systems (WFCS)}, publisher = {IEEE}, isbn = {978-1-6654-6432-1}, issn = {2835-8414}, doi = {10.1109/WFCS57264.2023.10144227}, abstract = {Time-Sensitive Networking (TSN) disrupts realtime communication technology by making IEEE Ethernet realtime-capable. For time-triggered, hard realtime traffic, TSN provides standardized mechanisms to reserve communication paths as well as individual transmission time slots for data frames. By leveraging these means in a precomputed network schedule, TSN allows for bounded end-to-end delays and minimal jitter. Not being part of the IEEE standard, corresponding scheduling algorithms are an active field of research. Unfortunately, due to differing model assumptions, evaluation setups, and key metrics, a fair comparison of schedulers is impossible so far. In this paper, we present a systematic and reproducible approach to benchmark TSN schedulers. First, we provide a scheduler taxonomy that enables to cluster schedulers by their characteristics. Second, we analyze interactions of input parameters and scheduler results to derive a benchmarking parcour for quantitative comparisons. Finally, we use the approach to benchmark existing schedulers and show subtle interaction effects. This way, our approach enables—for the first time-comparability between schedulers, fueled by the public availability of our benchmarking scenarios.}, language = {en} } @misc{WinklerHayat, author = {Winkler, Herwig and Hayat, Mubashir}, title = {Blockchain-Based Decentralized Product Lifecycle Management: A Framework for Production Network}, series = {IEEE International Conference on Industry Applications}, journal = {IEEE International Conference on Industry Applications}, doi = {10.1109/INDUSCON58041.2023.10374585}, abstract = {The current global trade wars, rising logistics costs, and the impact of the Covid-19 pandemic have compelled companies to re-evaluate their production strategies. An increasingly popular approach to address these issues is decentralized production, which involves manufacturing products near to the customers to reduce logistics and warehousing expenses, improve lead times, and decrease carbon emissions. However, the decentralized nature of the production network necessitates a secure communication platform for stakeholders to access authentic data in real-time. In this regard, blockchain technology is identified as a promising solution due to its characteristics, which make it suitable for product data management across its lifecycle, especially in a decentralized production network. Therefore, this work proposes a conceptual framework for a blockchainbased product lifecycle management (PLM) system to ensure data provenance, security, authenticity, and trusted traceability in a decentralized production network. Moreover, this study highlights that there is currently no such practical model available for decentralized production scenario. Consequently, we argue that successful deployment of a blockchain-based network would require a collaborative approach that involves close interaction and cooperation among all stakeholders in the network.}, language = {en} } @misc{BuhlHaertelBesong, author = {Buhl, Johannes and H{\"a}rtel, Sebastian and Besong, Lemopi Isidore}, title = {Temperature Control of the Two-Point Incremental Forming Process to Achieve Homogeneous Martensite Content Based on Finite Element Simulations}, series = {Proceedings of the 14th International Conference on the Technology of Plasticity - Current Trends in the Technology of Plasticity, ICTP 2023 - Volume 1}, journal = {Proceedings of the 14th International Conference on the Technology of Plasticity - Current Trends in the Technology of Plasticity, ICTP 2023 - Volume 1}, editor = {Mocellin, Katia}, publisher = {Springer}, address = {Cham}, isbn = {978-3-031-41022-2}, issn = {2195-4356}, doi = {10.1007/978-3-031-41023-9_74}, pages = {739 -- 747}, abstract = {Deformation-induced martensite has been observed in the incremental sheet forming of metastable austenitic stainless steels (MASS). The presence of martensite improves the characteristics of the springs. Martensite transformation usually occurs at low temperatures (<70 ℃). Depending on the tool speed, incremental forming of disk springs requires between 3 to 5 min. The forming time needs to be short to increase the process output in industrial settings. However, accelerating the process leads to high temperatures above the martensite transformation temperature that suppress martensite formation, necessitating temperature control during forming. It is suggested to enhance the martensite content of the blank by cooling during the forming operation. In this contribution, two-point incremental sheet forming is conducted to determine the influence of process temperature on the phase content of MASS disk springs. A temperature-dependent phase change material model that includes the strain rate effect is implemented in finite element (FE) simulations to predict the martensite content. FE simulations are performed to investigate the convection coefficients and cooling time leading to process temperatures below 70 ℃. The framework can be used to control and speed up the incremental forming of disk springs while maintaining a high martensite content.}, language = {en} } @misc{NakosBeirowWirsumetal., author = {Nakos, Alex and Beirow, Bernd and Wirsum, Manfred and Schafferus, Markus and Sasakaros, Marios and Vogt, Damian and Zobel, Arthur}, title = {Mistuning and Damping of a Radial Turbine Wheel. Part 3: Validation of Intentional Mistuning During Machine Operation}, series = {Proceedings of ASME Turbo Expo 2023, Boston, Massachusetts, June 26-30, 2023}, journal = {Proceedings of ASME Turbo Expo 2023, Boston, Massachusetts, June 26-30, 2023}, isbn = {978-0-7918-8706-6}, doi = {10.1115/GT2023-101993}, abstract = {This contribution investigates the implementation and verification of intentional mistuning (IM) to a radial turbine wheel of an exhaust turbocharger. In principle, inaccuracies in manufacture or material inhomogeneities may lead to random blade mistuning and thus localized modes with severely magnified blade vibrations can occur. With regard to axial compressors and turbines, IM has proved to be an efficient measure to mitigate the forced response. For radial turbine wheels, on the other hand, a successful implementation of IM into a wheel hardware has not yet been presented. This work aims at the design, implementation, and verification of successful IM considering both measurements at standstill and test runs on a turbocharger test rig. The fundamental analyses have been carried out in part one [1] of this three-part paper in order to find a suitable IM-pattern featuring only two different blade designs. The AABB sequence was identified to be the most promising one in terms of mitigating the maximum forced response of the fundamental bending mode at the considered operating point. In concrete terms, a 40\% attenuation of the maximum forced response was predicted by employing reduced order models. The second part [2] discussed the detailed geometric adaption of the turbine wheel hardware focussing on the implementation and validation of the IM pattern under laboratory conditions (standstill). Part three is about validating the efficacy of IM under operating conditions. In that sense, the successful implementation of IM and thus the machining of the wheel hardware are investigated within the framework of test runs on a turbocharger test rig. Test runs are conducted for both a wheel with and a wheel without IM. Non-intrusive blade-tip-timing (BTT) technology is employed to record forced response data. A well-known approach to evaluate the raw data namely times of arrival (TOA) without the availability of a once-per-revolution (OPR) signal is adapted, implemented, and applied for the evaluation. The results are compared to those received by using a commercial evaluation software for BTT measurement data. Finally, the actual gain achieved by means of IM is discussed in detail.}, language = {en} } @misc{GrafPippigLehnertetal., author = {Graf, Marcel and Pippig, Robert and Lehnert, Tim and Jedynak, Angelika and H{\"a}rtel, Sebastian}, title = {Aluminium-Matrix-Composites (AMC) for Hot Forged Components}, series = {Proceedings of the 14th International Conference on the Technology of Plasticity - Current Trends in the Technology of Plasticity, ICTP 2023 - Volume 1}, journal = {Proceedings of the 14th International Conference on the Technology of Plasticity - Current Trends in the Technology of Plasticity, ICTP 2023 - Volume 1}, editor = {Mocellin, Katia}, publisher = {Springer Nature Switzerland}, address = {Cham}, isbn = {978-3-031-41022-2}, issn = {2195-4356}, doi = {10.1007/978-3-031-41023-9_4}, pages = {36 -- 47}, abstract = {The development of new materials or material systems is always accompanied by the development of processing technologies suitable for the material. The reduction of process steps, the saving of material and the optimization of material properties are aims of forming processes. The basis for this is the comprehensive characterisation of the thermos-physical and thermos-mechanical technologically relevant material behaviour, taking into account the real process conditions. In the present work, the material-specific process limits were determined by means of experimental simulation and used in the numerical simulation in order, on the one hand, to identify the forming steps for optimizing the manufacturing conditions and, on the other hand, to be able to set the final material properties. It was essential to homogenize the casting microstructure for the forming processes and to adjust it to globulitical grains by solution annealing. The previously limited forming behaviour of the cast AlSi9Mg alloy with 20 vol.-\% SiC could be increased thus to forging-relevant plastic strains without occurring damages. Based on the comprehensive temperature-dependent material data, a one-step and resource-efficient manufacturing process for AMC materials by hot forming could be developed with the help of the FE software Simufact Forming and validated in reality under near-industrial conditions.}, language = {en} } @misc{JhanjiSydowAdamsetal., author = {Jhanji, Avantika and Sydow, Benjamin and Adams, Tom-Eric and Habisch, Stefan and H{\"a}rtel, Sebastian}, title = {Influence of the Initial Microstructure on the Mechanical Behavior During Forming for Inline Manufacturing Process Routes}, series = {Proceedings of the 14th International Conference on the Technology of Plasticity - Current Trends in the Technology of Plasticity, ICTP 2023 - Volume 2}, journal = {Proceedings of the 14th International Conference on the Technology of Plasticity - Current Trends in the Technology of Plasticity, ICTP 2023 - Volume 2}, publisher = {Springer Nature Switzerland}, address = {Cham}, isbn = {978-3-031-40919-6}, issn = {2195-4356}, doi = {10.1007/978-3-031-40920-2_53}, pages = {513 -- 524}, abstract = {With a view of sustainability and the rising energy costs currently, manufacturing processes of metals are becoming increasingly focused on optimizing process parameters such as energy and time consumption. A conventional hot-forming process route currently involves casting an ingot, letting it cool down, and heating it up again for the hot-forming process (see Fig. 1a). In order to implement the combination of casting and forging, avoiding the reheating cycle and using less energy, by utilizing the casting heat (see Fig. 1b), a methodology was developed within the present work to quantify the influence of the resulting microstructure as a function of the cooling rate on the forming and recrystallization behavior (see Fig. 1c). For this purpose, AISI 301 austenitic stainless-steel cast samples with different cast cooling rates were generated. An in-situ high-temperature microscope is used to determine the holding time and the heating rate. Dilatometer tests are performed to characterize the interaction between initial microstructure and the flow curves to verify the determination method (see Fig. 1d). The aim was to demonstrate whether the microstructure evolution and mechanical behavior is affected by the initial microstructure. The flow curves and the post-forming microstructure show a higher degree of recrystallization in fast-cooled microstructure than slow-cooled microstructure. Hence, it was found that the initial microstructure and the associated temperature history does have an impact on the mechanical properties.}, language = {en} } @misc{NeumannHaertel, author = {Neumann, Andreas and H{\"a}rtel, Sebastian}, title = {Limitations of a new forming process for vault structured recuperator tubes}, series = {Proceedings of the 14th International Conference on the Technology of Plasticity - Current Trends in the Technology of Plasticity ICTP 2023 - Volume 1}, journal = {Proceedings of the 14th International Conference on the Technology of Plasticity - Current Trends in the Technology of Plasticity ICTP 2023 - Volume 1}, editor = {Mocellin, Katia}, edition = {1}, publisher = {Springer Nature}, address = {Cham, Schweiz}, isbn = {978-3-031-41022-2}, issn = {2195-4356}, doi = {10.1007/978-3-031-41023-9_58}, pages = {577 -- 583}, abstract = {Classic forming technologies can make a difference to a climate-neutral economy. This also applies to the production of innovative hydrogen coolers (recuperators). To improve the efficiency of hydrogen coolers, heat transfer and heat flux can be increased by tube structures made by pressing spherical elements on their surface. Hydrogen is passed through the tubes of the recuperators and the cooling medium flows across it (Figure 1a). The tube serves as an atmosphere separator. Structured tubes can increase the power den-sity with the same dimensions. Figure 1b shows a process for introducing the structure into the pipe using radially and symmetrically arranged tools. Sheet metal forming usually involves pressing with structural tools, bending into a tube, and longitudinally welding. However, producing small tube diameters in the range of one inch presents a technical challenge. The challenge considered in this paper is to develop a new structuring process while maintaining the structural integrity and wall thickness of the tubes. This study aims to determine the feasibility of a multi-stage vault structuring process for recuperator tubes us-ing heat-resistant semi-finished products.}, language = {en} } @misc{JaegerSydowSchmidtetal., author = {J{\"a}ger, Reyk and Sydow, Benjamin and Schmidt, Alexander and Witt, Susanne and H{\"a}rtel, Sebastian}, title = {Design and Manufacturing of a Lightweight Press-Hardening Forming Tool by Wire Arc Additive Manufacturing}, series = {Proceedings of the 14th International Conference on the Technology of Plasticity - Current Trends in the Technology of Plasticity, Volume 3}, journal = {Proceedings of the 14th International Conference on the Technology of Plasticity - Current Trends in the Technology of Plasticity, Volume 3}, editor = {Mocellin, Katia}, publisher = {Springer}, isbn = {978-3-031-41340-7}, issn = {2195-4364}, doi = {10.1007/978-3-031-41341-4_25}, pages = {235 -- 246}, abstract = {Press-hardening is an important metal sheet manufacturing process to improve the metal sheet properties during forming with an inline quenching process. This requires higher cooling rates often obtained by cooling channels within the tools, that enable the formation of martensite for a high strength. The manufacturing of those forming tools with internal cooling channels is quite complex, time and material consuming and therefore expensive. Optimal cooling channel geometry cannot be realized by conventional machining operations, that limits cooling efficiency too. Wire Arc Additive Manufacturing (WAAM) is a layer-wise welding process, that allows the manufacturing of near net shapes and internal cooling channels. In contrast to conventional machining, manufacturing of a complex lightweight design forming tool can be realized by WAAM. This will further reduce the WAAM process time and material consumption. However, the lightweight design reduces on one hand the thermal mass and thus the capability of heat transfer, making cooling via the cooling channels more crucial. On the other hand, elastic tool deformation has to be as low as possible. In this study, a press-hardening forming tool made of S235JR is designed and manufactured by means of WAAM. FEM analysis are performed to optimize the design of the forming tool regarding lightweight aspects. Simple near net shapes of cooling channels are considered for a simplification of the WAAM process. The forming tool is mechanically tested to compare and evaluate the stiffness with the FEM analysis.}, language = {en} } @misc{BuergerSimonHernschier, author = {B{\"u}rger, Andreas and Simon, Sylvio and Hernschier, Stephan}, title = {Design of an energy-autonomous sensor with wireless data data transmission for use on rollers}, series = {MikroSystemTechnik Kongress 2023, 23.-25 Oktober, Dresden}, journal = {MikroSystemTechnik Kongress 2023, 23.-25 Oktober, Dresden}, number = {1}, edition = {1}, publisher = {VDE Verlag GmbH}, address = {Berlin}, isbn = {978-3-8007-6203-3}, doi = {10.5281/zenodo.10535511}, pages = {166 -- 171}, abstract = {Mechanically moving parts such as rollers in belt conveyor systems are subject to wear and tear that limits their service life. Damage causes loss of production as well as damage to the entire production plant. A system design is presented with which it is possible to record and wirelessly transmit relevant measured values in or on rollers without an additional voltage source. The system should work largely maintenance-free and be realisable with components currently freely available on the market.}, language = {de} } @misc{RadowRodriguezMansouriYarahmadietal., author = {Radow, Georg and Rodriguez, Giuseppe and Mansouri Yarahmadi, Ashkan and Breuß, Michael}, title = {Photometric Stereo with Non-Lambertian Preprocessing and Hayakawa Lighting Estimation for Highly Detailed Shape Reconstruction}, series = {Mathematical Methods for Objects Reconstruction : From 3D Vision to 3D Printing}, journal = {Mathematical Methods for Objects Reconstruction : From 3D Vision to 3D Printing}, editor = {Cristiani, Emiliano}, publisher = {Springer}, address = {Singapore}, isbn = {978-981-99-0775-5}, issn = {978-981-99-0776-2}, doi = {10.1007/978-981-99-0776-2_2}, pages = {35 -- 56}, abstract = {In many realistic scenarios, the use of highly detailed photometric 3D reconstruction techniques is hindered by several challenges in given imagery. Especially, the light sources are often unknown and need to be estimated, and the light reflectance is often non-Lambertian. In addition, when approaching the problem to apply photometric techniques at real-world imagery, several parameters appear that need to be fixed in order to obtain high-quality reconstructions. In this chapter, we attempt to tackle these issues by combining photometric stereo with non-Lambertian preprocessing and Hayakawa lighting estimation. At hand of a dedicated study, we discuss the applicability of these techniques for their use in automated 3D geometry recovery for 3D printing.}, language = {en} }