@article{EngelmannBuhlDraacketal.2018, author = {Engelmann, Ulrich M. and Buhl, Eva Miriam and Draack, Sebastian and Viereck, Thilo and Frank, and Schmitz-Rode, Thomas and Slabu, Ioana}, title = {Magnetic relaxation of agglomerated and immobilized iron oxide nanoparticles for hyperthermia and imaging applications}, series = {IEEE Magnetic Letters}, volume = {9}, journal = {IEEE Magnetic Letters}, number = {Article number 8519617}, publisher = {IEEE}, address = {New York, NY}, issn = {1949-307X}, doi = {10.1109/LMAG.2018.2879034}, year = {2018}, abstract = {Magnetic nanoparticles (MNPs) are used as therapeutic and diagnostic agents for local delivery of heat and image contrast enhancement in diseased tissue. Besides magnetization, the most important parameter that determines their performance for these applications is their magnetic relaxation, which can be affected when MNPs immobilize and agglomerate inside tissues. In this letter, we investigate different MNP agglomeration states for their magnetic relaxation properties under excitation in alternating fields and relate this to their heating efficiency and imaging properties. With focus on magnetic fluid hyperthermia, two different trends in MNP heating efficiency are measured: an increase by up to 23\% for agglomerated MNP in suspension and a decrease by up to 28\% for mixed states of agglomerated and immobilized MNP, which indicates that immobilization is the dominant effect. The same comparatively moderate effects are obtained for the signal amplitude in magnetic particle spectroscopy.}, language = {en} } @article{BergmannGoettenBraunetal.2022, author = {Bergmann, Ole and G{\"o}tten, Falk and Braun, Carsten and Janser, Frank}, title = {Comparison and evaluation of blade element methods against RANS simulations and test data}, series = {CEAS Aeronautical Journal}, volume = {13}, journal = {CEAS Aeronautical Journal}, publisher = {Springer}, address = {Wien}, issn = {1869-5590 (Online)}, doi = {10.1007/s13272-022-00579-1}, pages = {535 -- 557}, year = {2022}, abstract = {This paper compares several blade element theory (BET) method-based propeller simulation tools, including an evaluation against static propeller ground tests and high-fidelity Reynolds-Average Navier Stokes (RANS) simulations. Two proprietary propeller geometries for paraglider applications are analysed in static and flight conditions. The RANS simulations are validated with the static test data and used as a reference for comparing the BET in flight conditions. The comparison includes the analysis of varying 2D aerodynamic airfoil parameters and different induced velocity calculation methods. The evaluation of the BET propeller simulation tools shows the strength of the BET tools compared to RANS simulations. The RANS simulations underpredict static experimental data within 10\% relative error, while appropriate BET tools overpredict the RANS results by 15-20\% relative error. A variation in 2D aerodynamic data depicts the need for highly accurate 2D data for accurate BET results. The nonlinear BET coupled with XFOIL for the 2D aerodynamic data matches best with RANS in static operation and flight conditions. The novel BET tool PropCODE combines both approaches and offers further correction models for highly accurate static and flight condition results.}, language = {en} } @inproceedings{NeuJanserKhatibietal.2016, author = {Neu, Eugen and Janser, Frank and Khatibi, Akbar A. and Orifici, Adrian C.}, title = {In-flight vibration-based structural health monitoring of aircraft wings}, series = {30th Congress of the internatonal council of the aeronautical sciences : 25.-30. September 2016, Daejeon, Korea}, booktitle = {30th Congress of the internatonal council of the aeronautical sciences : 25.-30. September 2016, Daejeon, Korea}, pages = {10 Seiten}, year = {2016}, abstract = {This work presents a methodology for automated damage-sensitive feature extraction and anomaly detection under multivariate operational variability for in-flight assessment of wings. The method uses a passive excitation approach, i. e. without the need for artificial actuation. The modal system properties (natural frequencies and damping ratios) are used as damage-sensitive features. Special emphasis is placed on the use of Fiber Bragg Grating (FBG) sensing technology and the consideration of Operational and Environmental Variability (OEV). Measurements from a wind tunnel investigation with a composite cantilever equipped with FBG and piezoelectric sensors are used to successfully detect an impact damage. In addition, the feasibility of damage localisation and severity estimation is evaluated based on the coupling found between damageand OEV-induced feature changes.}, language = {en} } @inproceedings{KleineKallweitMichauxetal.2016, author = {Kleine, Harald and Kallweit, Stephan and Michaux, Frank and Havermann, Marc and Olivier, Herbert}, title = {PIV Measurement of Shock Wave Diffraction}, series = {18th International Symposium on Applications of Laser Techniques to Fluid Mechanics, 2016, Lissabon}, booktitle = {18th International Symposium on Applications of Laser Techniques to Fluid Mechanics, 2016, Lissabon}, pages = {1 -- 14}, year = {2016}, language = {en} } @inproceedings{DinghoferHartung2020, author = {Dinghofer, Kai and Hartung, Frank}, title = {Analysis of Criteria for the Selection of Machine Learning Frameworks}, series = {2020 International Conference on Computing, Networking and Communications (ICNC)}, booktitle = {2020 International Conference on Computing, Networking and Communications (ICNC)}, publisher = {IEEE}, address = {New York, NY}, doi = {10.1109/ICNC47757.2020.9049650}, pages = {373 -- 377}, year = {2020}, abstract = {With the many achievements of Machine Learning in the past years, it is likely that the sub-area of Deep Learning will continue to deliver major technological breakthroughs [1]. In order to achieve best results, it is important to know the various different Deep Learning frameworks and their respective properties. This paper provides a comparative overview of some of the most popular frameworks. First, the comparison methods and criteria are introduced and described with a focus on computer vision applications: Features and Uses are examined by evaluating papers and articles, Adoption and Popularity is determined by analyzing a data science study. Then, the frameworks TensorFlow, Keras, PyTorch and Caffe are compared based on the previously described criteria to highlight properties and differences. Advantages and disadvantages are compared, enabling researchers and developers to choose a framework according to their specific needs.}, language = {en} } @article{DefosseKleinschmidtSchmutzetal.2022, author = {Defosse, Jerome and Kleinschmidt, Joris and Schmutz, Axel and Loop, Torsten and Staat, Manfred and Gatzweiler, Karl-Heinz and Wappler, Frank and Schieren, Mark}, title = {Dental strain on maxillary incisors during tracheal intubation with double-lumen tubes and different laryngoscopy techniques - a blinded manikin study}, series = {Journal of Cardiothoracic and Vascular Anesthesia}, volume = {36}, journal = {Journal of Cardiothoracic and Vascular Anesthesia}, number = {8, Part B}, publisher = {Elsevier}, address = {New York, NY}, issn = {1053-0770}, doi = {10.1053/j.jvca.2022.02.017}, pages = {3021 -- 3027}, year = {2022}, language = {en} } @inproceedings{AuthCzarneckiBensberg2019, author = {Auth, Gunnar and Czarnecki, Christian and Bensberg, Frank}, title = {Impact of robotic process automation on enterprise architectures}, series = {GI Edition Proceedings Band 295 INFORMATIK 2019, Workshop-Beitr{\"a}ge}, booktitle = {GI Edition Proceedings Band 295 INFORMATIK 2019, Workshop-Beitr{\"a}ge}, editor = {Draude, Claude and Lange, Martin and Sick, Bernhard and Gesellschaft f{\"u}r Informatik e.V. (GI),}, publisher = {K{\"o}llen}, address = {Bonn}, isbn = {9783885796893}, issn = {1617-5468}, doi = {10.18420/inf2019_ws05}, pages = {59 -- 65}, year = {2019}, abstract = {The initial idea of Robotic Process Automation (RPA) is the automation of business processes through the presentation layer of existing application systems. For this simple emulation of user input and output by software robots, no changes of the systems and architecture is required. However, considering strategic aspects of aligning business and technology on an enterprise level as well as the growing capabilities of RPA driven by artificial intelligence, interrelations between RPA and Enterprise Architecture (EA) become visible and pose new questions. In this paper we discuss the relationship between RPA and EA in terms of perspectives and implications. As workin- progress we focus on identifying new questions and research opportunities related to RPA and EA.}, language = {en} } @inproceedings{BensbergAuthCzarneckietal.2018, author = {Bensberg, Frank and Auth, Gunnar and Czarnecki, Christian and W{\"o}rndle, Christopher}, title = {Transforming literature-intensive research processes through text analytics - design, implementation and lessons learned}, editor = {Kemal İlter, H.}, doi = {10.6084/m9.figshare.7582073.v1}, pages = {9 Seiten}, year = {2018}, abstract = {The continuing growth of scientific publications raises the question how research processes can be digitalized and thus realized more productively. Especially in information technology fields, research practice is characterized by a rapidly growing volume of publications. For the search process various information systems exist. However, the analysis of the published content is still a highly manual task. Therefore, we propose a text analytics system that allows a fully digitalized analysis of literature sources. We have realized a prototype by using EBSCO Discovery Service in combination with IBM Watson Explorer and demonstrated the results in real-life research projects. Potential addressees are research institutions, consulting firms, and decision-makers in politics and business practice.}, language = {en} } @inproceedings{MertensPuetzBrauneretal.2021, author = {Mertens, Alexander and P{\"u}tz, Sebastian and Brauner, Philipp and Brillowski, Florian Sascha and Buczak, Nadine and Dammers, Hannah and van Dyck, Marc and Kong, Iris and K{\"o}nigs, Peter and Kortomeikel, Frauke Carole and Rodemann, Niklas and Schaar, Anne Kathrin and Steuer-Dankert, Linda and Wlecke, Shari and Gries, Thomas and Leicht-Scholten, Carmen and Nagel, Saskia K. and Piller, Frank Thomas and Schuh, G{\"u}nther and Ziefle, Martina and Nitsch, Verena}, title = {Human digital shadow: Data-based modeling of users and usage in the internet of production}, series = {14th Conference Human System Interaction Conference Proceedings}, booktitle = {14th Conference Human System Interaction Conference Proceedings}, publisher = {IEEE}, doi = {10.1109/HSI52170.2021.9538729}, pages = {1 -- 8}, year = {2021}, abstract = {Digital Shadows as the aggregation, linkage and abstraction of data relating to physical objects are a central vision for the future of production. However, the majority of current research takes a technocentric approach, in which the human actors in production play a minor role. Here, the authors present an alternative anthropocentric perspective that highlights the potential and main challenges of extending the concept of Digital Shadows to humans. Following future research methodology, three prospections that illustrate use cases for Human Digital Shadows across organizational and hierarchical levels are developed: human-robot collaboration for manual work, decision support and work organization, as well as human resource management. Potentials and challenges are identified using separate SWOT analyses for the three prospections and common themes are emphasized in a concluding discussion.}, language = {en} } @inproceedings{MertensBraunerBaieretal.2022, author = {Mertens, Alexander and Brauner, Philipp and Baier, Ralph and Brillowski, Florian and Dammers, Hannah and van Dyck, Marc and Kong, Iris and K{\"o}nigs, Peter and Kordtomeikel, Frauke and Liehner, Gian Luca and P{\"u}tz, Sebastian and Rodermann, Niklas and Schaar, Anne Kathrin and Steuer-Dankert, Linda and Vervier, Luisa and Wlecke, Shari and Gries, Thomas and Leicht-Scholten, Carmen and Nagel, Saskia K. and Piller, Frank T. and Schuh, G{\"u}nther and Ziefle, Martina and Nitsch, Verena}, title = {Modelling Human Factors in Cyber Physical Production Systems by the Integration of Human Digital Shadows}, series = {Modellierung 2022 Satellite Events}, booktitle = {Modellierung 2022 Satellite Events}, editor = {Michael, Judith and Pfeiffer, J{\´e}r{\^o}me and Wortmann, Andreas}, publisher = {GI Gesellschaft f{\"u}r Informatik}, address = {Bonn}, doi = {10.18420/modellierung2022ws-018}, pages = {147 -- 149}, year = {2022}, abstract = {The future of industrial manufacturing and production will increasingly manifest in the form of cyber-physical production systems. Here, Digital Shadows will act as mediators between the physical and digital world to model and operationalize the interactions and relationships between different entities in production systems. Until now, the associated concepts have been primarily pursued and implemented from a technocentric perspective, in which human actors play a subordinate role, if they are considered at all. This paper outlines an anthropocentric approach that explicitly considers the characteristics, behavior, and traits and states of human actors in socio-technical production systems. For this purpose, we discuss the potentials and the expected challenges and threats of creating and using Human Digital Shadows in production.}, language = {en} } @incollection{BensbergAuthCzarnecki2021, author = {Bensberg, Frank and Auth, Gunnar and Czarnecki, Christian}, title = {Finding the perfect RPA match : a criteria-based selection method for RPA solutions}, series = {Robotic process automation : Management, technology, applications}, booktitle = {Robotic process automation : Management, technology, applications}, editor = {Czarnecki, Christian and Fettke, Peter}, publisher = {De Gruyter}, address = {Oldenbourg}, isbn = {978-3-11-067677-8}, doi = {10.1515/9783110676693-201}, pages = {47 -- 75}, year = {2021}, abstract = {The benefits of robotic process automation (RPA) are highly related to the usage of commercial off-the-shelf (COTS) software products that can be easily implemented and customized by business units. But, how to find the best fitting RPA product for a specific situation that creates the expected benefits? This question is related to the general area of software evaluation and selection. In the face of more than 75 RPA products currently on the market, guidance considering those specifics is required. Therefore, this chapter proposes a criteria-based selection method specifically for RPA. The method includes a quantitative evaluation of costs and benefits as well as a qualitative utility analysis based on functional criteria. By using the visualization of financial implications (VOFI) method, an application-oriented structure is provided that opposes the total cost of ownership to the time savings times salary (TSTS). For the utility analysis a detailed list of functional criteria for RPA is offered. The whole method is based on a multi-vocal review of scientific and non-scholarly literature including publications by business practitioners, consultants, and vendors. The application of the method is illustrated by a concrete RPA example. The illustrated structures, templates, and criteria can be directly utilized by practitioners in their real-life RPA implementations. In addition, a normative decision process for selecting RPA alternatives is proposed before the chapter closes with a discussion and outlook.}, language = {en} } @incollection{SchneiderWisselinkNoelleetal.2020, author = {Schneider, Dominik and Wisselink, Frank and N{\"o}lle, Nikolai and Czarnecki, Christian}, title = {Influence of artificial intelligence on commercial interactions in the consumer market}, series = {Automatisierung und Personalisierung von Dienstleistungen : Methoden - Potenziale - Einsatzfelder}, booktitle = {Automatisierung und Personalisierung von Dienstleistungen : Methoden - Potenziale - Einsatzfelder}, editor = {Bruhn, Manfred and Hadwich, Karsten}, publisher = {Springer Gabler}, address = {Wiesbaden}, isbn = {978-3-658-30167-5 (Print)}, doi = {10.1007/978-3-658-30168-2_7}, pages = {183 -- 205}, year = {2020}, abstract = {Recently, novel AI-based services have emerged in the consumer market. AI-based services can affect the way consumers take commercial decisions. Research on the influence of AI on commercial interactions is in its infancy. In this chapter, a framework creating a first overview of the influence of AI on commercial interactions is introduced. This framework summarizes the findings of comparing numerous customer journeys of novel AI-based services with corresponding non-AI equivalents.}, language = {en} } @incollection{BensbergBuscherCzarnecki2019, author = {Bensberg, Frank and Buscher, Gandalf and Czarnecki, Christian}, title = {Digital transformation and IT topics in the consulting industry: a labor market perspective}, series = {Advances in consulting research : recent findings and practical cases}, booktitle = {Advances in consulting research : recent findings and practical cases}, editor = {Nissen, Volker}, publisher = {Springer}, address = {Cham}, isbn = {978-3-319-95998-6}, doi = {10.1007/978-3-319-95999-3_16}, pages = {341 -- 357}, year = {2019}, abstract = {Information technologies, such as big data analytics, cloud computing, cyber physical systems, robotic process automation, and the internet of things, provide a sustainable impetus for the structural development of business sectors as well as the digitalization of markets, enterprises, and processes. Within the consulting industry, the proliferation of these technologies opened up the new segment of digital transformation, which focuses on setting up, controlling, and implementing projects for enterprises from a broad range of sectors. These recent developments raise the question, which requirements evolve for IT consultants as important success factors of those digital transformation projects. Therefore, this empirical contribution provides indications regarding the qualifications and competences necessary for IT consultants in the era of digital transformation from a labor market perspective. On the one hand, this knowledge base is interesting for the academic education of consultants, since it supports a market-oriented design of adequate training measures. On the other hand, insights into the competence requirements for consultants are considered relevant for skill and talent management processes in consulting practice. Assuming that consulting companies pursue a strategic human resource management approach, labor market information may also be useful to discover strategic behavioral patterns.}, language = {en} } @article{IkenBronderGoretzkietal.2019, author = {Iken, Heiko and Bronder, Thomas and Goretzki, Alexander and Kriesel, Jana and Ahlborn, Kristina and Gerlach, Frank and Vonau, Winfried and Zander, Willi and Schubert, J{\"u}rgen and Sch{\"o}ning, Michael Josef}, title = {Development of a Combined pH- and Redox-Sensitive Bi-Electrode Glass Thin-Film Sensor}, series = {physica status solidi a : applications and materials sciences}, volume = {216}, journal = {physica status solidi a : applications and materials sciences}, number = {12}, publisher = {Wiley}, address = {Weinheim}, issn = {1862-6319}, doi = {10.1002/pssa.201900114}, pages = {1 -- 8}, year = {2019}, language = {en} } @inproceedings{WaldmannVeraDachwaldetal.2018, author = {Waldmann, Christoph and Vera, Jean-Pierre de and Dachwald, Bernd and Strasdeit, Henry and Sohl, Frank and Hanff, Hendrik and Kowalski, Julia and Heinen, Dirk and Macht, Sabine and Bestmann, Ulf and Meckel, Sebastian and Hildebrandt, Marc and Funke, Oliver and Gehrt, Jan-J{\"o}ran}, title = {Search for life in ice-covered oceans and lakes beyond Earth}, series = {2018 IEEE/OES Autonomous Underwater Vehicle Workshop, Proceedings November 2018, Article number 8729761}, booktitle = {2018 IEEE/OES Autonomous Underwater Vehicle Workshop, Proceedings November 2018, Article number 8729761}, doi = {10.1109/AUV.2018.8729761}, year = {2018}, abstract = {The quest for life on other planets is closely connected with the search for water in liquid state. Recent discoveries of deep oceans on icy moons like Europa and Enceladus have spurred an intensive discussion about how these waters can be accessed. The challenge of this endeavor lies in the unforeseeable requirements on instrumental characteristics both with respect to the scientific and technical methods. The TRIPLE/nanoAUV initiative is aiming at developing a mission concept for exploring exo-oceans and demonstrating the achievements in an earth-analogue context, exploring the ocean under the ice shield of Antarctica and lakes like Dome-C on the Antarctic continent.}, language = {en} } @article{BartellaKamalScholletal.2019, author = {Bartella, Alexander K. and Kamal, Mohammad and Scholl, Ingrid and Schiffer, Stefan and Steegmann, Julius and Ketelsen, Dominik and H{\"o}lzle, Frank W. and Lethaus, Bernd}, title = {Virtual reality in preoperative imaging in maxillofacial surgery: implementation of "the next level"?}, series = {British Journal of Oral and Maxillofacial Surgery}, volume = {57}, journal = {British Journal of Oral and Maxillofacial Surgery}, number = {7}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0266-4356}, doi = {10.1016/j.bjoms.2019.02.014}, pages = {644 -- 648}, year = {2019}, language = {en} } @inproceedings{HoevelerJanser2016, author = {Hoeveler, Bastian and Janser, Frank}, title = {The aerodynamically optimized design of a fan-in-wing duct}, series = {Applied Aerodynamics Research Conference 2016, Bristol, GB, Jul 19-21, 2016}, booktitle = {Applied Aerodynamics Research Conference 2016, Bristol, GB, Jul 19-21, 2016}, isbn = {1-85768-371-4}, pages = {1 -- 10}, year = {2016}, language = {en} } @inproceedings{GaldiHartungDugelay2019, author = {Galdi, Chiara and Hartung, Frank and Dugelay, Jean-Luc}, title = {Socrates: A database of realistic data for source camera recognition on smartphones}, series = {Proceedings of the 8th International Conference on Pattern Recognition Applications and Methods - Volume 1: ICPRAM}, booktitle = {Proceedings of the 8th International Conference on Pattern Recognition Applications and Methods - Volume 1: ICPRAM}, isbn = {978-989-758-351-3}, doi = {10.5220/0007403706480655}, pages = {648 -- 655}, year = {2019}, language = {en} } @article{HoevelerBauknechtWolfetal.2020, author = {Hoeveler, B. and Bauknecht, Andr{\´e} and Wolf, C. Christian and Janser, Frank}, title = {Wind-Tunnel Study of a Wing-Embedded Lifting Fan Remaining Open in Cruise Flight}, series = {Journal of Aircraft}, volume = {57}, journal = {Journal of Aircraft}, number = {4}, publisher = {AIAA}, address = {Reston, Va.}, issn = {1533-3868}, doi = {10.2514/1.C035422}, year = {2020}, abstract = {It is investigated whether a nonrotating lifting fan remaining uncovered during cruise flight, as opposed to being covered by a shutter system, can be realized with limited additional drag and loss of lift during cruise flight. A wind-tunnel study of a wing-embedded lifting fan has been conducted at the Side Wind Test Facility G{\"o}ttingen of DLR, German Aerospace Center in G{\"o}ttingen using force, pressure, and stereoscopic particle image velocimetry techniques. The study showed that a step on the lower side of the wing in front of the lifting fan duct increases the lift-to-drag ratio of the whole model by up to 25\% for all positive angles of attack. Different sizes and inclinations of the step had limited influence on the surface pressure distribution. The data indicate that these parameters can be optimized to maximize the lift-to-drag ratio. A doubling of the curvature radius of the lifting fan duct inlet lip on the upper side of the wing affected the lift-to-drag ratio by less than 1\%. The lifting fan duct inlet curvature can therefore be optimized to maximize the vertical fan thrust of the rotating lifting fan during hovering without affecting the cruise flight performance with a nonrotating fan.}, language = {en} } @article{NeuJanserKhatibietal.2017, author = {Neu, Eugen and Janser, Frank and Khatibi, Akbar A. and Orifici, Adrian C.}, title = {Fully Automated Operational Modal Analysis using multi-stage clustering}, series = {Mechanical Systems and Signal Processing}, volume = {Vol. 84, Part A}, journal = {Mechanical Systems and Signal Processing}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0888-3270}, doi = {10.1016/j.ymssp.2016.07.031}, pages = {308 -- 323}, year = {2017}, language = {en} } @article{NeuJanserKhatibietal.2016, author = {Neu, Eugen and Janser, Frank and Khatibi, Akbar A. and Orifici, Adrian C.}, title = {Automated modal parameter-based anomaly detection under varying wind excitation}, series = {Structural Health Monitoring}, volume = {15}, journal = {Structural Health Monitoring}, number = {6}, publisher = {Sage}, address = {London}, issn = {1475-9217}, doi = {10.1177/1475921716665803}, pages = {1 -- 20}, year = {2016}, abstract = {Wind-induced operational variability is one of the major challenges for structural health monitoring of slender engineering structures like aircraft wings or wind turbine blades. Damage sensitive features often show an even bigger sensitivity to operational variability. In this study a composite cantilever was subjected to multiple mass configurations, velocities and angles of attack in a controlled wind tunnel environment. A small-scale impact damage was introduced to the specimen and the structural response measurements were repeated. The proposed damage detection methodology is based on automated operational modal analysis. A novel baseline preparation procedure is described that reduces the amount of user interaction to the provision of a single consistency threshold. The procedure starts with an indeterminate number of operational modal analysis identifications from a large number of datasets and returns a complete baseline matrix of natural frequencies and damping ratios that is suitable for subsequent anomaly detection. Mahalanobis distance-based anomaly detection is then applied to successfully detect the damage under varying severities of operational variability and with various degrees of knowledge about the present operational conditions. The damage detection capabilities of the proposed methodology were found to be excellent under varying velocities and angles of attack. Damage detection was less successful under joint mass and wind variability but could be significantly improved through the provision of the currently encountered operational conditions.}, language = {en} } @inproceedings{HammerViethMaier2005, author = {Hammer, Andreas and Vieth, Matthias and Maier, Frank}, title = {Co-Plot as a new multivariate analysis method for operations management research?}, series = {Papers of the 12th International EurOMA Conference on Operational and Global Competitiveness, Budapest, Hungary, June 19-22, 2005 / Editor: Krisztina Demeter}, booktitle = {Papers of the 12th International EurOMA Conference on Operational and Global Competitiveness, Budapest, Hungary, June 19-22, 2005 / Editor: Krisztina Demeter}, isbn = {963-218-455-6}, pages = {1007 -- 1016}, year = {2005}, language = {en} } @article{WertIkenSchoeningetal.2021, author = {Wert, Stefan and Iken, Heiko and Sch{\"o}ning, Michael Josef and Matysik, Frank-Michael}, title = {Development of a temperature-pulse enhanced electrochemical glucose biosensor and characterization of its stability via scanning electrochemical microscopy}, series = {Electroanalysis}, journal = {Electroanalysis}, number = {Early View}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1521-4109}, doi = {10.1002/elan.202100089}, year = {2021}, abstract = {Glucose oxidase (GOx) is an enzyme frequently used in glucose biosensors. As increased temperatures can enhance the performance of electrochemical sensors, we investigated the impact of temperature pulses on GOx that was drop-coated on flattened Pt microwires. The wires were heated by an alternating current. The sensitivity towards glucose and the temperature stability of GOx was investigated by amperometry. An up to 22-fold increase of sensitivity was observed. Spatially resolved enzyme activity changes were investigated via scanning electrochemical microscopy. The application of short (<100 ms) heat pulses was associated with less thermal inactivation of the immobilized GOx than long-term heating.}, language = {en} } @article{MoehrenBergmannJanseretal.2023, author = {M{\"o}hren, Felix and Bergmann, Ole and Janser, Frank and Braun, Carsten}, title = {On the influence of elasticity on propeller performance: a parametric study}, series = {CEAS Aeronautical Journal}, volume = {14}, journal = {CEAS Aeronautical Journal}, publisher = {Springer Nature}, address = {Berlin}, issn = {1869-5590 (Online)}, doi = {10.1007/s13272-023-00649-y}, pages = {311 -- 323}, year = {2023}, abstract = {The aerodynamic performance of propellers strongly depends on their geometry and, consequently, on aeroelastic deformations. Knowledge of the extent of the impact is crucial for overall aircraft performance. An integrated simulation environment for steady aeroelastic propeller simulations is presented. The simulation environment is applied to determine the impact of elastic deformations on the aerodynamic propeller performance. The aerodynamic module includes a blade element momentum approach to calculate aerodynamic loads. The structural module is based on finite beam elements, according to Timoshenko theory, including moderate deflections. Several fixed-pitch propellers with thin-walled cross sections made of both isotropic and non-isotropic materials are investigated. The essential parameters are varied: diameter, disc loading, sweep, material, rotational, and flight velocity. The relative change of thrust between rigid and elastic blades quantifies the impact of propeller elasticity. Swept propellers of large diameters or low disc loadings can decrease the thrust significantly. High flight velocities and low material stiffness amplify this tendency. Performance calculations without consideration of propeller elasticity can lead to decreased efficiency. To avoid cost- and time-intense redesigns, propeller elasticity should be considered for swept planforms and low disc loadings.}, language = {en} } @inproceedings{PuetzBaierBrauneretal.2022, author = {P{\"u}tz, Sebastian and Baier, Ralph and Brauner, Philipp and Brillowski, Florian and Dammers, Hannah and Liehner, Luca and Mertens, Alexander and Rodemann, Niklas and Schneider, Sebastian and Schollemann, Alexander and Steuer-Dankert, Linda and Vervier, Luisa and Gries, Thomas and Leicht-Scholten, Carmen and Nagel, Saskia K. and Piller, Frank T. and Schuh, G{\"u}nther and Ziefle, Martina and Nitsch, Verena}, title = {An interdisciplinary view on humane interfaces for digital shadows in the internet of production}, series = {2022 15th International Conference on Human System Interaction (HSI)}, booktitle = {2022 15th International Conference on Human System Interaction (HSI)}, publisher = {IEEE}, isbn = {978-1-6654-6823-7 (Print)}, issn = {2158-2246 (Print)}, doi = {10.1109/HSI55341.2022.9869467}, pages = {8 Seiten}, year = {2022}, abstract = {Digital shadows play a central role for the next generation industrial internet, also known as Internet of Production (IoP). However, prior research has not considered systematically how human actors interact with digital shadows, shaping their potential for success. To address this research gap, we assembled an interdisciplinary team of authors from diverse areas of human-centered research to propose and discuss design and research recommendations for the implementation of industrial user interfaces for digital shadows, as they are currently conceptualized for the IoP. Based on the four use cases of decision support systems, knowledge sharing in global production networks, human-robot collaboration, and monitoring employee workload, we derive recommendations for interface design and enhancing workers' capabilities. This analysis is extended by introducing requirements from the higher-level perspectives of governance and organization.}, language = {en} } @article{ElsenHartungHornetal.2001, author = {Elsen, Ingo and Hartung, Frank and Horn, Uwe and Kampmann, Markus and Peters, Liliane}, title = {Streaming technology in 3G mobile communication systems}, series = {Computer : innovative technology for computer professionals}, volume = {34}, journal = {Computer : innovative technology for computer professionals}, number = {9 Seiten}, editor = {Voas, Jeffrey}, publisher = {IEEE}, address = {New York}, issn = {0018-9162}, pages = {46 -- 52}, year = {2001}, abstract = {Third-generation mobile communication systems will combine standardized streaming with a range of unique services to provide high-quality Internet content that meets the specific needs of the rapidly growing mobile market.}, language = {en} } @article{BergmannMoehrenBraunetal.2023, author = {Bergmann, Ole and M{\"o}hren, Felix and Braun, Carsten and Janser, Frank}, title = {On the influence of elasticity on swept propeller noise}, series = {AIAA SCITECH 2023 Forum}, journal = {AIAA SCITECH 2023 Forum}, publisher = {AIAA}, address = {Reston, Va.}, doi = {10.2514/6.2023-0210}, year = {2023}, abstract = {High aerodynamic efficiency requires propellers with high aspect ratios, while propeller sweep potentially reduces noise. Propeller sweep and high aspect ratios increase elasticity and coupling of structural mechanics and aerodynamics, affecting the propeller performance and noise. Therefore, this paper analyzes the influence of elasticity on forward-swept, backward-swept, and unswept propellers in hover conditions. A reduced-order blade element momentum approach is coupled with a one-dimensional Timoshenko beam theory and Farassat's formulation 1A. The results of the aeroelastic simulation are used as input for the aeroacoustic calculation. The analysis shows that elasticity influences noise radiation because thickness and loading noise respond differently to deformations. In the case of the backward-swept propeller, the location of the maximum sound pressure level shifts forward by 0.5 °, while in the case of the forward-swept propeller, it shifts backward by 0.5 °. Therefore, aeroacoustic optimization requires the consideration of propeller deformation.}, language = {en} } @inproceedings{MoehrenBergmannJanseretal.2023, author = {M{\"o}hren, Felix and Bergmann, Ole and Janser, Frank and Braun, Carsten}, title = {On the determination of harmonic propeller loads}, series = {AIAA SCITECH 2023 Forum}, booktitle = {AIAA SCITECH 2023 Forum}, publisher = {AIAA}, doi = {10.2514/6.2023-2404}, pages = {12 Seiten}, year = {2023}, abstract = {Dynamic loads significantly impact the structural design of propeller blades due to fatigue and static strength. Since propellers are elastic structures, deformations and aerodynamic loads are coupled. In the past, propeller manufacturers established procedures to determine unsteady aerodynamic loads and the structural response with analytical steady-state calculations. According to the approach, aeroelastic coupling primarily consists of torsional deformations. They neglect bending deformations, deformation velocities, and inertia terms. This paper validates the assumptions above for a General Aviation propeller and a lift propeller for urban air mobility or large cargo drones. Fully coupled reduced-order simulations determine the dynamic loads in the time domain. A quasi-steady blade element momentum approach transfers loads to one-dimensional finite beam elements. The simulation results are in relatively good agreement with the analytical method for the General Aviation propeller but show increasing errors for the slender lift propeller. The analytical approach is modified to consider the induced velocities. Still, inertia and velocity proportional terms play a significant role for the lift propeller due to increased elasticity. The assumption that only torsional deformations significantly impact the dynamic loads of propellers is not valid. Adequate determination of dynamic loads of such designs requires coupled aeroelastic simulations or advanced analytical procedures.}, language = {en} } @inproceedings{GaldiHartungDugelay2017, author = {Galdi, Chiara and Hartung, Frank and Dugelay, Jean-Luc}, title = {Videos versus still images: Asymmetric sensor pattern noise comparison on mobile phones}, series = {Electronic Imaging}, booktitle = {Electronic Imaging}, publisher = {Society for Imaging Science and Technology}, address = {Springfield, Virginia}, issn = {2470-1173}, doi = {10.2352/ISSN.2470-1173.2017.7.MWSF-331}, pages = {100 -- 103}, year = {2017}, abstract = {Nowadays, the most employed devices for recoding videos or capturing images are undoubtedly the smartphones. Our work investigates the application of source camera identification on mobile phones. We present a dataset entirely collected by mobile phones. The dataset contains both still images and videos collected by 67 different smartphones. Part of the images consists in photos of uniform backgrounds, especially collected for the computation of the RSPN. Identifying the source camera given a video is particularly challenging due to the strong video compression. The experiments reported in this paper, show the large variation in performance when testing an highly accurate technique on still images and videos.}, language = {en} } @misc{LindelGreiserWaxmanetal.2012, author = {Lindel, Tomasz Dawid and Greiser, Andreas and Waxman, Patrick and Dietterle, Martin and Seifert, Frank and Fontius, Ulrich and Renz, Wolfgang and Dieringer, Matthias A. and Frauenrath, Tobias and Schulz-Menger, Jeanette and Niendorf, Thoralf and Ittermann, Bernd}, title = {Cardiac CINE MRI at 7 T using a transmit array}, series = {2012 ISMRM Annual Meeting Proceedings}, journal = {2012 ISMRM Annual Meeting Proceedings}, issn = {1545-4428}, year = {2012}, abstract = {With its need for high SNR and short acquisition times, Cardiac MRI (CMR) is an intriguing target application for ultrahigh field MRI. Due to the sheer size of the upper torso, however, the known RF issues of 7T MRI are also most prominent in CMR. Recent years brought substantial progress but the full potential of the ultrahigh field for CMR is yet to be exploited. Parallel transmission (pTx) is a promising approach in this context and several groups have already reported B1 shimming for 7T CMR. In such a static pTx application amplitudes and phases of all Tx channels are adjusted individually but otherwise imaging techniques established in current clinical practice 1.5 T and 3 T are applied. More advanced forms of pTx as spatially selective excitation (SSE) using Transmit SENSE promise additional benefits like faster imaging with reduced fields of view or improved SAR control. SSE requires the full dynamic capabilities of pTx, however, and for the majority of today's implemented pTx hardware the internal synchronization of the Tx array does not easily permit external triggering as needed for CMR. Here we report a software solution to this problem and demonstrate the feasibility of CINE CMR at 7 T using a Tx array.}, language = {en} } @article{DieringerRenzLindeletal.2011, author = {Dieringer, Matthias A. and Renz, Wolfgang and Lindel, Tomasz D. and Seifert, Frank and Frauenrath, Tobias and von Knobelsdorf-Brenkenhoff, Florian and Waiczies, Helmar and Hoffmann, Werner and Rieger, Jan and Pfeiffer, Harald and Ittermann, Bernd and Schulz-Menger, Jeanette and Niendorf, Thoralf}, title = {Design and application of a four-channel transmit/receive surface coil for functional cardiac imaging at 7T}, series = {Journal of Magnetic Resonance Imaging}, volume = {33}, journal = {Journal of Magnetic Resonance Imaging}, number = {3}, publisher = {Wiley-Liss}, address = {New York}, issn = {1522-2586}, doi = {10.1002/jmri.22451}, pages = {736 -- 741}, year = {2011}, abstract = {Purpose To design and evaluate a four-channel cardiac transceiver coil array for functional cardiac imaging at 7T. Materials and Methods A four-element cardiac transceiver surface coil array was developed with two rectangular loops mounted on an anterior former and two rectangular loops on a posterior former. specific absorption rate (SAR) simulations were performed and a Burn:x-wiley:10531807:media:JMRI22451:tex2gif-stack-1 calibration method was applied prior to obtain 2D FLASH CINE (mSENSE, R = 2) images from nine healthy volunteers with a spatial resolution of up to 1 × 1 × 2.5 mm3. Results Tuning and matching was found to be better than 10 dB for all subjects. The decoupling (S21) was measured to be >18 dB between neighboring loops, >20 dB for opposite loops, and >30 dB for other loop combinations. SAR values were well within the limits provided by the IEC. Imaging provided clinically acceptable signal homogeneity with an excellent blood-myocardium contrast applying the Burn:x-wiley:10531807:media:JMRI22451:tex2gif-stack-2 calibration approach. Conclusion A four-channel cardiac transceiver coil array for 7T was built, allowing for cardiac imaging with clinically acceptable signal homogeneity and an excellent blood-myocardium contrast. Minor anatomic structures, such as pericardium, mitral, and tricuspid valves and their apparatus, as well as trabeculae, were accurately delineated.}, language = {en} } @article{MoehrenBergmannJanseretal.2024, author = {M{\"o}hren, Felix and Bergmann, Ole and Janser, Frank and Braun, Carsten}, title = {Assessment of structural mechanical effects related to torsional deformations of propellers}, series = {CEAS Aeronautical Journal}, journal = {CEAS Aeronautical Journal}, publisher = {Springer}, address = {Wien}, issn = {1869-5590 (eISSN)}, doi = {10.1007/s13272-024-00737-7}, pages = {22 Seiten}, year = {2024}, abstract = {Lifting propellers are of increasing interest for Advanced Air Mobility. All propellers and rotors are initially twisted beams, showing significant extension-twist coupling and centrifugal twisting. Torsional deformations severely impact aerodynamic performance. This paper presents a novel approach to assess different reasons for torsional deformations. A reduced-order model runs large parameter sweeps with algebraic formulations and numerical solution procedures. Generic beams represent three different propeller types for General Aviation, Commercial Aviation, and Advanced Air Mobility. Simulations include solid and hollow cross-sections made of aluminum, steel, and carbon fiber-reinforced polymer. The investigation shows that centrifugal twisting moments depend on both the elastic and initial twist. The determination of the centrifugal twisting moment solely based on the initial twist suffers from errors exceeding 5\% in some cases. The nonlinear parts of the torsional rigidity do not significantly impact the overall torsional rigidity for the investigated propeller types. The extension-twist coupling related to the initial and elastic twist in combination with tension forces significantly impacts the net cross-sectional torsional loads. While the increase in torsional stiffness due to initial twist contributes to the overall stiffness for General and Commercial Aviation propellers, its contribution to the lift propeller's stiffness is limited. The paper closes with the presentation of approximations for each effect identified as significant. Numerical evaluations are necessary to determine each effect for inhomogeneous cross-sections made of anisotropic material.}, language = {en} } @incollection{SchneiderWisselinkCzarneckietal.2024, author = {Schneider, Dominik and Wisselink, Frank and Czarnecki, Christian and N{\"o}lle, Nikolai}, title = {Benefits and framework conditions for information-driven business models concerning the Internet of Things}, series = {Digitalization in companies}, booktitle = {Digitalization in companies}, publisher = {Springer}, address = {Wiesbaden}, isbn = {978-3-658-39093-8 (Print)}, doi = {10.1007/978-3-658-39094-5_5}, pages = {59 -- 75}, year = {2024}, abstract = {In the context of the increasing digitalization, the Internet of Things (IoT) is seen as a technological driver through which completely new business models can emerge in the interaction of different players. Identified key players include traditional industrial companies, municipalities and telecommunications companies. The latter, by providing connectivity, ensure that small devices with tiny batteries can be connected almost anywhere and directly to the Internet. There are already many IoT use cases on the market that provide simplification for end users, such as Philips Hue Tap. In addition to business models based on connectivity, there is great potential for information-driven business models that can support or enhance existing business models. One example is the IoT use case Park and Joy, which uses sensors to connect parking spaces and inform drivers about available parking spaces in real time. Information-driven business models can be based on data generated in IoT use cases. For example, a telecommunications company can add value by deriving more decision-relevant information - called insights - from data that is used to increase decision agility. In addition, insights can be monetized. The monetization of insights can only be sustainable, if careful attention is taken and frameworks are considered. In this chapter, the concept of information-driven business models is explained and illustrated with the concrete use case Park and Joy. In addition, the benefits, risks and framework conditions are discussed.}, language = {en} } @article{SaretzkiBergmannDahmannetal.2021, author = {Saretzki, Charlotte and Bergmann, Ole and Dahmann, Peter and Janser, Frank and Keimer, Jona and Machado, Patricia and Morrison, Audry and Page, Henry and Pluta, Emil and St{\"u}bing, Felix and K{\"u}pper, Thomas}, title = {Are small airplanes safe with regards to COVID-19 transmission?}, series = {Journal of Travel Medicine}, volume = {28}, journal = {Journal of Travel Medicine}, number = {7}, publisher = {Oxford University Press}, address = {Oxford}, issn = {1708-8305}, doi = {10.1093/jtm/taab105}, year = {2021}, language = {en} } @misc{DieringerRenzLindeletal.2010, author = {Dieringer, Matthias A. and Renz, Wolfgang and Lindel, Tomasz and Seifert, Frank and Frauenrath, Tobias and Waiczies, Helmar and von Knobelsdorff-Brenkhoff, Florian and Santoro, Davide and Hoffmann, Werner and Ittermann, Bernd and Schulz-Menger, Jeanette and Niendorf, Thoralf}, title = {4CH TX/RX Surface Coil for 7T: Design, Optimization and Application for Cardiac Function Imaging}, series = {2010 ISMRM-ESMRMB joint annual meeting}, journal = {2010 ISMRM-ESMRMB joint annual meeting}, issn = {1545-4428}, year = {2010}, abstract = {Practical impediments of ultra high field cardiovascular MR (CVMR) can be catalogued in exacerbated magnetic field and radio frequency (RF) inhomogeneities, susceptibility and off-resonance effects, conductive and dielectric effects in tissue, and RF power deposition constraints, which all bear the potential to spoil the benefit of CVMR at 7T. Therefore, a four element cardiac transceive surface coil array was developed. Cardiac imaging provided clinically acceptable signal homogeneity with an excellent blood myocardium contrast. Subtle anatomic structures, such as pericardium, mitral and tricuspid valves and their apparatus, papillary muscles, and trabecles were accurately delineated.}, language = {en} } @inproceedings{MulsowHuelsenGuetzlaffetal.2023, author = {Mulsow, Niklas A. and H{\"u}lsen, Benjamin and G{\"u}tzlaff, Joel and Spies, Leon and Bresser, Andreas and Dabrowski, Adam and Czupalla, Markus and Kirchner, Frank}, title = {Concept and design of an autonomous micro rover for long term lunar exploration}, series = {Proceedings of the 74th International Astronautical Congress}, booktitle = {Proceedings of the 74th International Astronautical Congress}, publisher = {dfki}, address = {Saarbr{\"u}cken}, pages = {13 Seiten}, year = {2023}, abstract = {Research on robotic lunar exploration has seen a broad revival, especially since the Google Lunar X-Prize increasingly brought private endeavors into play. This development is supported by national agencies with the aim of enabling long-term lunar infrastructure for in-situ operations and the establishment of a moon village. One challenge for effective exploration missions is developing a compact and lightweight robotic rover to reduce launch costs and open the possibility for secondary payload options. Existing micro rovers for exploration missions are clearly limited by their design for one day of sunlight and their low level of autonomy. For expanding the potential mission applications and range of use, an extension of lifetime could be reached by surviving the lunar night and providing a higher level of autonomy. To address this objective, the paper presents a system design concept for a lightweight micro rover with long-term mission duration capabilities, derived from a multi-day lunar mission scenario at equatorial regions. Technical solution approaches are described, analyzed, and evaluated, with emphasis put on the harmonization of hardware selection due to a strictly limited budget in dimensions and power.}, language = {en} } @inproceedings{HuelsenMulsowDabrowskietal.2023, author = {H{\"u}lsen, Benjamin and Mulsow, Niklas A. and Dabrowski, Adam and Brinkmann, Wiebke and G{\"u}tzlaff, Joel and Spies, Leon and Czupalla, Markus and Kirchner, Frank}, title = {Towards an autonomous micro rover with night survivability for lunar exploration}, series = {Proceedings of the 74th International Astronautical Congress}, booktitle = {Proceedings of the 74th International Astronautical Congress}, publisher = {dfki}, pages = {12 Seiten}, year = {2023}, abstract = {In Europe, efforts are underway to develop key technologies that can be used to explore the Moon and to exploit the resources available. This includes technologies for in-situ resource utilization (ISRU), facilitating the possibility of a future Moon Village. The Moon is the next step for humans and robots to exploit the use of available resources for longer term missions, but also for further exploration of the solar system. A challenge for effective exploration missions is to achieve a compact and lightweight robot to reduce launch costs and open up the possibility of secondary payload options. Current micro rover concepts are primarily designed to last for one day of solar illumination and show a low level of autonomy. Extending the lifetime of the system by enabling survival of the lunar night and implementing a high level of autonomy will significantly increase potential mission applications and the operational range. As a reference mission, the deployment of a micro rover in the equatorial region of the Moon is being considered. An overview of mission parameters and a detailed example mission sequence is given in this paper. The mission parameters are based on an in-depth study of current space agency roadmaps, scientific goals, and upcoming flight opportunities. Furthermore, concepts of the ongoing international micro rover developments are analyzed along with technology solutions identified for survival of lunar nights and a high system autonomy. The results provide a basis of a concise requirements set-up to allow dedicated system developments and qualification measures in the future.}, language = {en} } @article{SchierenKleinschmidtSchmutzetal.2019, author = {Schieren, Mark and Kleinschmidt, Joris and Schmutz, Axel and Loop, Torsten and Gatzweiler, Karl-Heinz and Staat, Manfred and Wappler, Frank and Defosse, Jerome}, title = {Comparison of forces acting on maxillary incisors during tracheal intubation with different laryngoscopy techniques: a blinded manikin study}, series = {Anaesthesia}, volume = {74}, journal = {Anaesthesia}, number = {12}, publisher = {Wiley-Blackwell}, address = {Oxford}, isbn = {1365-2044}, doi = {10.1111/anae.14815}, year = {2019}, language = {en} } @article{RaffeisAdjeiKyeremehVroomenetal.2020, author = {Raffeis, Iris and Adjei-Kyeremeh, Frank and Vroomen, Uwe and Westhoff, Elmar and Bremen, Sebastian and Hohoi, Alexandru and B{\"u}hrig-Polaczek, Andreas}, title = {Qualification of a Ni-Cu alloy for the laser powder bed fusion process (LPBF): Its microstructure and mechanical properties}, series = {Applied Sciences}, volume = {10}, journal = {Applied Sciences}, number = {Art. 3401}, publisher = {MDPI}, address = {Basel}, issn = {2076-3417}, doi = {10.3390/app10103401}, pages = {1 -- 15}, year = {2020}, abstract = {As researchers continue to seek the expansion of the material base for additive manufacturing, there is a need to focus attention on the Ni-Cu group of alloys which conventionally has wide industrial applications. In this work, the G-NiCu30Nb casting alloy, a variant of the Monel family of alloys with Nb and high Si content is, for the first time, processed via the laser powder bed fusion process (LPBF). Being novel to the LPBF processes, optimum LPBF parameters were determined, and hardness and tensile tests were performed in as-built conditions and after heat treatment at 1000 °C. Microstructures of the as-cast and the as-built condition were compared. Highly dense samples (99.8\% density) were achieved after varying hatch distance (80 µm and 140 µm) with scanning speed (550 mm/s-1500 mm/s). There was no significant difference in microhardness between varied hatch distance print sets. Microhardness of the as-built condition (247 HV0.2) exceeded the as-cast microhardness (179 HV0.2.). Tensile specimens built in vertical (V) and horizontal (H) orientations revealed degrees of anisotropy and were superior to conventionally reported figures. Post heat treatment increased ductility from 20\% to 31\% (V), as well as from 16\% to 25\% (H), while ultimate tensile strength (UTS) and yield strength (YS) were considerably reduced.}, language = {en} }