@article{KralHaumerKapelleretal., author = {Kral, Christian and Haumer, Anton and Kapeller, Hansj{\"o}rg and Pirker, Franz}, title = {Design and Thermal Simulation of Induction Machines for Traction in Electric and Hybrid Electric Vehicles}, series = {World Electric Vehicle Journal}, volume = {1}, journal = {World Electric Vehicle Journal}, number = {1}, publisher = {MDPI}, issn = {2032-6653}, doi = {10.3390/wevj1010190}, pages = {190 -- 196}, abstract = {An electric traction machine for an electric or a hybrid electric vehicle is usually designed for a specific operating point or cycle. For such an operating point or cycle, the masses and the cooling circuit of the electric machine determine the time dependent temperature distribution within the machine. For a specific load cycle, the thermal simulation of the machine can reveal possible mass and size reductions for a given insulation class of the machine. In addition, such simulations allow the comparison of various cooling concepts. In the machine design process, the first step is a conventional electromagnetic machine design. From the geometric data of this design and the material properties, the parameters of a thermal equivalent circuit can be derived. The differential and algebraic equations of the thermal equivalent circuit are solved by a simulation tool to predict the temperatures of the critical parts in the electric machine. A thermal equivalent circuit is accurate enough to predict the thermal behavior of the critical parts in the electric machine, and yet not too complex, to obtain simulation results with moderate numerical effort. This enables an iterative design process to optimize the drive.}, language = {en} } @article{StadlerCornetFrenkler, author = {Stadler, Sebastian and Cornet, Henriette and Frenkler, Fritz}, title = {Assessing Heuristic Evaluation in Immersive Virtual Reality: A Case Study on Future Guidance Systems}, series = {Multimodal Technologies and Interaction}, volume = {7}, journal = {Multimodal Technologies and Interaction}, number = {2}, issn = {2414-4088}, doi = {10.3390/mti7020019}, pages = {19}, abstract = {A variety of evaluation methods for user interfaces (UI) exist such as usability testing, cognitive walkthrough, and heuristic evaluation. However, UIs such as guidance systems at transit hubs must be evaluated in their intended application field to allow the effective and valid identification of usability flaws. However, what if evaluations are not feasible in real environments, or laboratorial conditions cannot be ensured? Based on adapted heuristics, in the present study, the method of heuristic evaluation is combined with immersive Virtual Reality (VR) for the identification of usability flaws of dynamic guidance systems (DGS) at transit hubs. The study involved usability evaluations of nine DGS concepts using the newly proposed method. The results show that compared to computer-based heuristic evaluations, the use of immersive VR led to the identification of an increased amount of "severe" usability flaws as well as overall usability flaws. Within a qualitative assessment, immersive VR is validated as a suitable tool for conducting heuristic evaluations involving significant advantages such as the creation of realistic experiences in laboratorial conditions. Future work seeks to further prove the suitability of using immersive VR for heuristic evaluations and compare the proposed method to other evaluative methods.}, language = {en} } @article{CornetStadlerKongetal., author = {Cornet, Henriette and Stadler, Sebastian and Kong, Penny and Marinkovic, Goran and Frenkler, Fritz and Sathikh, Peer Mohideen}, title = {User-centred design of autonomous mobility for public transportation in Singapore}, series = {Transportation Research Procedia}, volume = {41}, journal = {Transportation Research Procedia}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2352-1465}, doi = {10.1016/j.trpro.2019.09.038}, pages = {191 -- 203}, abstract = {The paper presents a set of methods for user-centred design of autonomous mobility for public transportation in the context of a multi-disciplinary research programme in Singapore, called TUMCREATE. While traffic engineers plan the operation of the new mobility system, the Industrial Designers of TUMCREATE take on the role of designing the autonomous vehicles (AVs) and infrastructure for greater comfort and a positive travel experience for users. Tasks have been identified to promote user acceptance and facilitate the operation of autonomously driven vehicles for public transport. To fulfil these tasks, conventional design methods have been enhanced with Virtual Reality (VR) technology and with simulations developed by the computer scientists of TUMCREATE. Since public transportation is a complex and broad area, it cannot be investigated with a single design method. First results showed that conventional methods that consider the Universal Design principles guarantee the accessibility, usability and understandability of AVs and stations. VR has been identified as a suitable tool for Industrial Designers to evaluate communication concepts between AVs and pedestrians. This confirms that digital tools (i.e. VR) enhance conventional design methods, especially with regard to technologies that are not available on the market yet (e.g. AVs)}, language = {en} } @article{PourshahidiJeanKaulenetal., author = {Pourshahidi, Ali Mohammad and Jean, Neha and Kaulen, Corinna and Jakobi, Simon and Krause, Hans-Joachim}, title = {Impact of Particle Size on the Nonlinear Magnetic Response of Iron Oxide Nanoparticles during Frequency Mixing Magnetic Detection}, series = {Sensors}, volume = {24}, journal = {Sensors}, number = {13}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {10.3390/s24134223}, abstract = {Magnetic nanoparticles (MNPs), particularly iron oxide nanoparticles (IONPs), play a pivotal role in biomedical applications ranging from magnetic resonance imaging (MRI) enhancement and cancer hyperthermia treatments to biosensing. This study focuses on the synthesis, characterization, and application of IONPs with two different size distributions for frequency mixing magnetic detection (FMMD), a technique that leverages the nonlinear magnetization properties of MNPs for sensitive biosensing. IONPs are synthesized through thermal decomposition and subsequent growth steps. Our findings highlight the critical influence of IONP size on the FMMD signal, demonstrating that larger particles contribute dominantly to the FMMD signal. This research advances our understanding of IONP behavior, underscoring the importance of size in their application in advanced diagnostic tools.}, language = {en} } @inproceedings{StadlerCornetFrenkler, author = {Stadler, Sebastian and Cornet, Henriette and Frenkler, Fritz}, title = {Collecting People's Preferences in Immersive Virtual Reality: A Case Study on Public Spaces in Singapore, Germany, and France}, series = {Synergy - DRS International Conference 2020, 11-14 August, held online}, booktitle = {Synergy - DRS International Conference 2020, 11-14 August, held online}, editor = {Boess, S. and Cheung, M and Cain, R.}, publisher = {Design Research Society}, doi = {10.21606/drs.2020.308}, pages = {1185 -- 1200}, abstract = {In the design of urban public spaces, the inclusion of diverse voices enhances the development of products and services by synchronising designer expertise with people's preferences. Multiple participatory methods exist, each with their respective benefits and drawbacks in terms of the quality of results, time and cost needed for preparing and conducting studies, and knowledge required for participation. Providing more concrete representations of abstract or intangible design concepts would be beneficial for laypeople unfamiliar with design or the case study. We propose a Virtual Reality (VR) platform to discover subjective preferences on public waiting rooms through immersive design experiences. The VR platform was tested with 463 participants with variety in age and cultural background. Following a qualitative data analysis, we discuss the suitability of our VR platform for fostering inclusive participation and how it impacts the role of the designer, as well as propose design guidelines for future VR studies.}, language = {en} } @article{HimmeleinPerezRuizdeGaribayBrandeletal., author = {Himmelein, Susanne and Perez Ruiz de Garibay, Aritz and Brandel, Veronika and Zierfuß, Frank and Bingold, Tobias Michael}, title = {The ADVanced Organ Support (ADVOS) hemodialysis system removes IL-6: an in vitro proof-of-concept study}, series = {Intensive care medicine experimental}, volume = {12}, journal = {Intensive care medicine experimental}, number = {1}, publisher = {SpringerOpen}, address = {Berlin ; Heidelberg}, issn = {2197-425X}, doi = {10.1186/s40635-024-00652-5}, abstract = {BACKGROUND IL-6 is a pleiotropic cytokine modulating inflammation and metabolic pathways. Its proinflammatory effect plays a significant role in organ failure pathogenesis, commonly elevated in systemic inflammatory conditions. Extracorporeal blood purification devices, such as the Advanced Organ Support (ADVOS) multi hemodialysis system, might offer potential in mitigating IL-6's detrimental effects, yet its efficacy remains unreported. METHODS We conducted a proof-of-concept in vitro study to assess the ADVOS multi system's efficacy in eliminating IL-6. Varying concentrations of IL-6 were introduced into a swine blood model and treated with ADVOS multi for up to 12 h, employing different blood and concentrate flow rates. IL-6 reduction rate, clearance, and dynamics in blood and dialysate were analyzed. RESULTS IL-6 clearance rates of 0.70 L/h and 0.42 L/h were observed in 4 and 12-h experiments, respectively. No significant differences were noted across different initial concentrations. Reduction rates ranged between 40 and 46\% within the first 4 h, increasing up to 72\% over 12 h, with minimal impact from flow rate variations. Our findings suggest that an IL-6-albumin interaction and convective filtration are implicated in in vitro IL-6 elimination with ADVOS multi. CONCLUSIONS This study demonstrates for the first time an efficient and continuous in vitro removal of IL-6 by ADVOS multi at low blood flow rates. Initial concentration-dependent removal transitions to more consistent elimination over time. Further clinical investigations are imperative for comprehensive data acquisition.}, language = {en} } @article{UhrhanSchwindtWitte, author = {Uhrhan, Katja and Schwindt, Esther and Witte, Hartmut}, title = {Fabrication and Dielectric Validation of an Arm Phantom for Electromyostimulation}, series = {Bioengineering}, volume = {11}, journal = {Bioengineering}, number = {7}, publisher = {MDPI}, address = {Basel}, issn = {2306-5354}, doi = {10.3390/bioengineering11070724}, abstract = {Electromyostimulation (EMS) is an up-and-coming training method that demands further fundamental research regarding its safety and efficacy. To investigate the influence of different stimulation parameters, electrode positions and electrode sizes on the resulting voltage in the tissue, a tissue mimicking phantom is needed. Therefore, this study describes the fabrication of a hydrogel arm phantom for EMS applications with the tissue layers of skin, fat, blood and muscle. The phantom was dielectrically validated in the frequency range of 20 Hz to 100 Hz. We also conducted electromyography (EMG) recordings during EMS on the phantom and compared them with the same measurements on a human arm. The phantom reproduces the dielectric properties of the tissues with deviations ranging from 0.8\% to more than 100\%. Although we found it difficult to find a compromise between mimicking the permittivity and electrical conductivity at the same time, the EMS-EMG measurements showed similar waveforms (1.9-9.5\% deviation) in the phantom and human. Our research contributes to the field of dielectric tissue phantoms, as it proposes a multilayer arm phantom for EMS applications. Consequently, the phantom can be used for initial EMS investigations, but future research should focus on further improving the dielectric properties.}, language = {en} } @article{RoeslSeitz, author = {R{\"o}sl, Gerhard and Seitz, Franz}, title = {Uncertainty, politics, and crises: The case for cash}, series = {Latin American Journal of Central Banking}, volume = {5}, journal = {Latin American Journal of Central Banking}, number = {3}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2666-1438}, doi = {10.1016/j.latcb.2024.100128}, abstract = {We analyze the repercussions of different kinds of uncertainty on cash demand, including uncertainty of cashless infrastructures, confidence crises of the financial system, natural disasters, political uncertainties, and inflationary crises. Based on a comprehensive literature survey and complemented by case studies, we derive a classification scheme how cash holdings typically evolved in each of these types of uncertainty over the past 30 years by separating between demand for domestic and international cash as well as between transaction and store of value balances. Hereby, we focus on the stabilizing macroeconomic properties of cash and recommendguidelines for cash supply by central banks and the banking system. Finally, we exemplify ouranalysis with five case studies from the developing world, namely Venezuela, Zimbabwe, Afghanistan, Iraq, and Libya.}, language = {en} } @inproceedings{LauxErdődiSelgrad, author = {Laux, Lea and Erdődi, L{\´a}szl{\´o} and Selgrad, Kai}, title = {Trust as the Elephant in the Room: Security Evaluation of Decentralized Online Social Networks with Mastodon}, series = {Norsk IKT-konferanse for forskning og utdanning}, booktitle = {Norsk IKT-konferanse for forskning og utdanning}, number = {3}, abstract = {Federated online social networks are an alternative to centralized and often profit-driven social networks. Instead of providing exactly one main platform, federated and decentralized approaches consist of multiple platforms, nodes or instances, leading to new challenges for guaranteeing confidentiality, integrity and availability. In addition, privacy is taken into close consideration due to the sensitive nature of processed personal data and the purpose of online social networks as well as the user behavior on social media. The recent popularity and broad use of the federated micro-blogging platform Mastodon issues the matter of security and privacy challenges for this type of architecture and the specific platform as well. Mastodon is part of a larger network called Fediverse with several platforms with different purposes. Communication and interoperability between Fediverse platforms is mostly achieved by ActivityPub protocol as standard for decentralized social networking, defined by W3C. We analyze Mastodon as the currently most prominent and largest example of a Fediverse platform. Therefore, we perform tests for typical types of software vulnerabilities as well as evaluate common security challenges built into its design. As a result, we identify trust as security principle as critical issue, leading to multiple weak points such as enabling attackers and malicious actors to spread misleading information as well as network availability impacts. We suggest possible solutions customized to our findings as well as general security recommendations when building a federated online social network such as the Fediverse}, language = {en} } @inproceedings{ZwingelKediliogluReitelshoeferetal., author = {Zwingel, Maximilian and Kedilioglu, Oguz and Reitelsh{\"o}fer, Sebastian and Mauerer, Wolfgang}, title = {Optimization Problems in Production and Planning: Approaches and Limitations in View of Possible Quantum Superiority}, series = {Annals of Scientific Society for Assembly, Handling and Industrial Robotics 2023}, booktitle = {Annals of Scientific Society for Assembly, Handling and Industrial Robotics 2023}, publisher = {Springer Nature}, isbn = {9783031740091}, language = {en} }