TY - JOUR A1 - Bartella, Alexander K. A1 - Kamal, Mohammad A1 - Scholl, Ingrid A1 - Schiffer, Stefan A1 - Steegmann, Julius A1 - Ketelsen, Dominik A1 - Hölzle, Frank W. A1 - Lethaus, Bernd T1 - Virtual reality in preoperative imaging in maxillofacial surgery: implementation of “the next level”? JF - British Journal of Oral and Maxillofacial Surgery Y1 - 2019 U6 - https://doi.org/10.1016/j.bjoms.2019.02.014 SN - 0266-4356 VL - 57 IS - 7 SP - 644 EP - 648 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Hoeveler, Bastian A1 - Janser, Frank T1 - The aerodynamically optimized design of a fan-in-wing duct T2 - Applied Aerodynamics Research Conference 2016, Bristol, GB, Jul 19-21, 2016 Y1 - 2016 SN - 1-85768-371-4 N1 - G1-3-paper.pdf SP - 1 EP - 10 ER - TY - CHAP A1 - Galdi, Chiara A1 - Hartung, Frank A1 - Dugelay, Jean-Luc T1 - Socrates: A database of realistic data for source camera recognition on smartphones T2 - Proceedings of the 8th International Conference on Pattern Recognition Applications and Methods - Volume 1: ICPRAM Y1 - 2019 SN - 978-989-758-351-3 U6 - https://doi.org/10.5220/0007403706480655 SP - 648 EP - 655 ER - TY - JOUR A1 - Hoeveler, B. A1 - Bauknecht, André A1 - Wolf, C. Christian A1 - Janser, Frank T1 - Wind-Tunnel Study of a Wing-Embedded Lifting Fan Remaining Open in Cruise Flight JF - Journal of Aircraft N2 - 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 Göttingen of DLR, German Aerospace Center in Göttingen 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. Y1 - 2020 U6 - https://doi.org/10.2514/1.C035422 SN - 1533-3868 VL - 57 IS - 4 PB - AIAA CY - Reston, Va. ER - TY - JOUR A1 - Neu, Eugen A1 - Janser, Frank A1 - Khatibi, Akbar A. A1 - Orifici, Adrian C. T1 - Fully Automated Operational Modal Analysis using multi-stage clustering JF - Mechanical Systems and Signal Processing Y1 - 2017 U6 - https://doi.org/10.1016/j.ymssp.2016.07.031 SN - 0888-3270 VL - Vol. 84, Part A SP - 308 EP - 323 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Neu, Eugen A1 - Janser, Frank A1 - Khatibi, Akbar A. A1 - Orifici, Adrian C. T1 - Automated modal parameter-based anomaly detection under varying wind excitation JF - Structural Health Monitoring N2 - 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. Y1 - 2016 U6 - https://doi.org/10.1177/1475921716665803 SN - 1475-9217 VL - 15 IS - 6 SP - 1 EP - 20 PB - Sage CY - London ER - TY - JOUR A1 - Wert, Stefan A1 - Iken, Heiko A1 - Schöning, Michael Josef A1 - Matysik, Frank-Michael T1 - Development of a temperature‐pulse enhanced electrochemical glucose biosensor and characterization of its stability via scanning electrochemical microscopy JF - Electroanalysis N2 - 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. Y1 - 2021 U6 - https://doi.org/10.1002/elan.202100089 SN - 1521-4109 IS - Early View PB - Wiley-VCH CY - Weinheim ER - TY - BOOK A1 - Janser, Frank A1 - Havermann, Marc A1 - Hoeveler, Bastian A1 - Hertz, Cyril A1 - Bergmann, Ole T1 - Strömungslehre und Aerodynamik : inkompressible Profile und Tragflügelaerodynamik, Band 2 N2 - Das vorliegende Buch dient als Grundlage für die Bachelor- und Master-Ausbildung von Studierenden im Fachgebiet Strömungslehre und Aerodynamik. Im hier behandelten Teilbereich der inkompressiblen Profile und Tragflügelaerodynamik werden schwerpunktmäßig die folgenden Themen besprochen: - Profilaerodynamik - Tragflügelaerodynamik - Flugzeugpolare - Methoden zur Flugbereichserweiterung - Schwebeschub und Schwebeleistung - Propellerblattaerodynamik - Numerische Methoden zur Tragflügelberechnung Y1 - 2023 SN - 978-3-8107-0261-6 PB - Mainz CY - Aachen ET - 4. Auflage ER - TY - CHAP A1 - Galdi, Chiara A1 - Hartung, Frank A1 - Dugelay, Jean-Luc T1 - Videos versus still images: Asymmetric sensor pattern noise comparison on mobile phones T2 - Electronic Imaging N2 - 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. KW - Image Forensics KW - Mobile Phones KW - Image Database Y1 - 2017 U6 - https://doi.org/10.2352/ISSN.2470-1173.2017.7.MWSF-331 SN - 2470-1173 N1 - IS&T International Symposium on Electronic Imaging 2017 Media Watermarking, Security, and Forensics 2017 SP - 100 EP - 103 PB - Society for Imaging Science and Technology CY - Springfield, Virginia ER - TY - JOUR A1 - Bergmann, Ole A1 - Götten, Falk A1 - Braun, Carsten A1 - Janser, Frank T1 - Comparison and evaluation of blade element methods against RANS simulations and test data JF - CEAS Aeronautical Journal N2 - 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. KW - BET KW - CFD propeller simulation KW - Propeller aerodynamics KW - Actuator disk modelling KW - Propeller performance Y1 - 2022 U6 - https://doi.org/10.1007/s13272-022-00579-1 SN - 1869-5590 (Online) SN - 1869-5582 (Print) N1 - Corresponding author: Ole Bergmann VL - 13 SP - 535 EP - 557 PB - Springer CY - Wien ER - TY - JOUR A1 - Raffeis, Iris A1 - Adjei-Kyeremeh, Frank A1 - Vroomen, Uwe A1 - Westhoff, Elmar A1 - Bremen, Sebastian A1 - Hohoi, Alexandru A1 - Bührig-Polaczek, Andreas T1 - Qualification of a Ni-Cu alloy for the laser powder bed fusion process (LPBF): Its microstructure and mechanical properties JF - Applied Sciences N2 - 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. Y1 - 2020 U6 - https://doi.org/10.3390/app10103401 SN - 2076-3417 N1 - Special Issue Materials Development by Additive Manufacturing Techniques VL - 10 IS - Art. 3401 SP - 1 EP - 15 PB - MDPI CY - Basel ER - TY - JOUR A1 - Elsen, Ingo A1 - Hartung, Frank A1 - Horn, Uwe A1 - Kampmann, Markus A1 - Peters, Liliane ED - Voas, Jeffrey T1 - Streaming technology in 3G mobile communication systems JF - Computer : innovative technology for computer professionals N2 - 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. Y1 - 2001 SN - 0018-9162 SN - 1558-0814 VL - 34 IS - 9 Seiten SP - 46 EP - 52 PB - IEEE CY - New York ER - TY - CHAP A1 - Chudoba, Rostislav A1 - Butenweg, Christoph A1 - Pfeiffer, Frank T1 - Textile reinforced concrete. Part I: Process model for collaborative research and development T2 - Digital proceedings / IKM 2003, proceedings 16th International Conference on the Applications of Computer Science and Mathematics in Architecture and Civil Engineering [Elektronische Ressource : 10. - 12. Juni 2003, Weimar] / Bauhaus-Universität Weimar. Ed.: K. Gürlebeck; L. Hempel; C. Könke Y1 - 2003 SP - 1 EP - 8 PB - IKM CY - Weimar ER - TY - JOUR A1 - Möhren, Felix A1 - Bergmann, Ole A1 - Janser, Frank A1 - Braun, Carsten T1 - On the influence of elasticity on propeller performance: a parametric study JF - CEAS Aeronautical Journal N2 - 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. KW - Propeller KW - Finite element method KW - Blade element method KW - Propeller elasticity KW - Aeroelasticity Y1 - 2023 U6 - https://doi.org/10.1007/s13272-023-00649-y SN - 1869-5590 (Online) SN - 1869-5582 (Print) N1 - Corresponding author: Felix Möhren VL - 14 SP - 311 EP - 323 PB - Springer Nature CY - Berlin ER - TY - CHAP A1 - Möhren, Felix A1 - Bergmann, Ole A1 - Janser, Frank A1 - Braun, Carsten T1 - On the determination of harmonic propeller loads T2 - AIAA SCITECH 2023 Forum N2 - 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. Y1 - 2023 U6 - https://doi.org/10.2514/6.2023-2404 N1 - AIAA SCITECH 2023 Forum, 23-27 January 2023, National Harbor, Md & Online PB - AIAA ER - TY - BOOK A1 - Engeln-Müllges, Gisela A1 - Uhlig, Frank T1 - Numerical algorithms with C Y1 - 1996 SN - 3-540-60530-0 PB - Springer CY - Berlin [u.a.] ER - TY - BOOK A1 - Engeln-Müllges, Gisela A1 - Uhlig, Frank T1 - Numeric Algorithms with Fortran Y1 - 1996 SN - 3-540-60529-0 PB - Springer CY - Berlin [u.a.] ER - TY - JOUR A1 - Ferrein, Alexander A1 - Dylla, Frank A1 - Lakemeyer, Gerhard A1 - Murray, Jan T1 - Approaching a formal soccer theory from behaviour specifications in robotic soccer / Dylla, Frank ; Ferrein, Alexander ; Lakemeyer, Gerhard ; Murray, Jan ; Obst, Oliver ; Röfer, Thomas ; Schiffer, Stefan ; Stolzenburg, Frieder ; Visser, Ubbo ; Wagner, Tho JF - Computers in sport / editors: P Dabnichki Y1 - 2008 SN - 978-1-8456-4064-4 SP - 161 EP - 185 PB - WIT Press CY - Southampton ER - TY - CHAP A1 - Waldmann, Christoph A1 - Vera, Jean-Pierre de A1 - Dachwald, Bernd A1 - Strasdeit, Henry A1 - Sohl, Frank A1 - Hanff, Hendrik A1 - Kowalski, Julia A1 - Heinen, Dirk A1 - Macht, Sabine A1 - Bestmann, Ulf A1 - Meckel, Sebastian A1 - Hildebrandt, Marc A1 - Funke, Oliver A1 - Gehrt, Jan-Jöran T1 - Search for life in ice-covered oceans and lakes beyond Earth T2 - 2018 IEEE/OES Autonomous Underwater Vehicle Workshop, Proceedings November 2018, Article number 8729761 N2 - 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. KW - Planetary exploration KW - Jupiter KW - ice moons KW - underwater vehicle KW - Antarctica Y1 - 2018 U6 - https://doi.org/10.1109/AUV.2018.8729761 ER - TY - THES A1 - Frank, Jemima Leonie T1 - Falling in love with the female gaze N2 - Der „Male Gaze“ bezeichnet das typische Erleben der Umwelt aus männlicher Perspektive und prägt in den sogenannten Mainstream-Medien die Gestaltung von Film, Fernsehen und Werbung. Dadurch werden von dargestellten Personen häufig die körperlichen Aspekte hervorgehoben. Im Gegensatz dazu gilt das weibliche Pendant, der „Female Gaze“, als besonders emotionsbetont. Weil Medien einen enormen Einfluss auf gesellschaftliches und individuelles Denken haben, stellt die Dominanz des „Male Gaze“ eine Unausgeglichenheit dar, die sich in verschiedenen Bereichen des gesellschaftlichen Lebens widerspiegelt. Deswegen möchte dieses Projekt die Medien um die weibliche Sichtweise erweitern und damit die dort transportierten Bilder diverser und ausgewogener machen. Die Fotografie fokussiert sich dabei auf die Gefühlswelt der Protagonistin, womit die Betrachter:Innen schrittweise in ihre Position hineinversetzt werden sollen. Mit Augen des Mitgefühls und eigenem Schönheitsbegriff lässt „Falling in love with the female gaze“ endlich auch die Frau zu Wort kommen. KW - Weiblicher Blick KW - Fotografie KW - Emotional KW - Fühlen KW - Portrait Y1 - 2022 N1 - Für diese Arbeit steht kein Volltext zur Verfügung. PB - FH Aachen CY - Aachen ER -