@article{GilleKruegerWeber2022, author = {Gille, Christoph and Kr{\"u}ger, Christine and W{\´e}ber, J{\´u}lia}, title = {Influences of the far right on social work in Germany: systematic attacks and daily shifts}, series = {European Journal of Social Work}, volume = {26}, journal = {European Journal of Social Work}, number = {3}, publisher = {Taylor \& Francis}, issn = {1369-1457}, doi = {10.1080/13691457.2022.2063810}, pages = {561 -- 574}, year = {2022}, subject = {Rechtsradikalismus}, language = {en} } @article{ReimsTophoven2021, author = {Reims, Nancy and Tophoven, Silke}, title = {Double Burden of Disability and Poverty: Does Vocational Rehabilitation Ease the School-to-Work Transition?}, series = {Social Inclusion}, volume = {9}, journal = {Social Inclusion}, number = {4}, publisher = {Cogitatio}, issn = {2183-2803}, doi = {10.17645/si.v9i4.4649}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-40131}, pages = {92 -- 102}, year = {2021}, abstract = {Poor young people more often face health difficulties, (learning) disabilities, and are overrepresented in special schools. Consequently, youth from poor households disproportionately frequently participate in disability-specific programs aiming to improve their educational levels and labor market opportunities. They face a double burden of disability and poverty. In our study, we look at poor and non-poor youth with disabilities (YPWD) who participate in vocational rehabilitation (VR) and whether VR helps them (a) in transitioning into employment and (b) in leaving poverty. We examine the association between the receipt of initial basic income support (BIS) as a poverty indicator, later labor market outcomes, and earned vocational qualification using administrative data. We make use of a sample of all persons accepted for VR in 2010 (N = 36,645). We employ logit models on VR attendees' labor market outcomes three and five years after being accepted for VR as well as on their earned vocational qualifications. Beside initial poverty status, we control for educational level, type, and degree of disability and program pattern during the VR process. Our findings show that YPWD from poor households have a decreased likelihood of a vocational certificate and employment. Additionally, they are more likely to receive BIS than young people not from poor households and thus more likely to remain poor. In conclusion, VR seems to support poor YPWD less in their school-to-work transitions. Thus, disability-specific programs should be more tailored to the social situations of participants, and counsellors should be more sensitive to their social backgrounds.}, language = {en} } @article{Manthe2021, author = {Manthe, Barbara}, title = {On the Pathway to Violence: West German Right-Wing Terrorism in the 1970s}, series = {Terrorism and Political Violence}, volume = {33}, journal = {Terrorism and Political Violence}, number = {1}, publisher = {Taylor \& Francis}, issn = {0954-6553}, doi = {10.1080/09546553.2018.1520701}, pages = {49 -- 70}, year = {2021}, language = {en} } @inproceedings{GalleArellanoCondeetal.2015, author = {Galle, Bo and Arellano, Santiago and Conde, Vladimir and Pfeffer, Melissa and Barsotti, Sara and Stefansdottir, Gerður and Bergsson, Baldur and Bergsson, Bergur and Ingvarsson, Thorgils and Weber, Konradin}, title = {Ground based measurements of the gas emission from the Holuhraun volcanic fissure eruption on Iceland 2014/2015}, series = {Geophysical Research Abstracts: EGU General Assembly 2015}, volume = {17}, booktitle = {Geophysical Research Abstracts: EGU General Assembly 2015}, publisher = {Copernicus}, address = {G{\"o}ttingen}, year = {2015}, abstract = {The since 31 August 2014 ongoing volcanic eruption at Holuhraun on Iceland is by far the strongest source of sulfur dioxide in Europe over the last 230 years with sustained emission rates exceeding 100 000 ton/day. This gas emission severely affects local population and has become a concern also for air traffic. The eruption has in December continued at constant pace for 3.5 months. Three scenarios are envisaged for the future; (1) the eruption stops, (2) the fissure extends under the Vattnaj{\"o}kul glacier and (3) Bardarbunga volcano erupts. The two later scenarios will cause increased gas emission, severe ash emissions and extended flooding. Under the scope of the EU-project FUTUREVOLC, a project with 3.5 years duration, aiming at making Iceland a supersite for volcanological research as a European contribution to GEO, we are developing a version of the Scanning DOAS instrument that is adapted to high latitudes with low UV radiation and severe meteorological conditions. Since the first day of the eruption several of these novel instruments has been monitoring the SO2 emission from the eruption. Data from our instruments are still after 3.5 months the only sustained ground-based monitoring of this gas emission. A lot of work is however needed to sustain this operation at a very remote site and under severe field conditions. At the same time the very high concentrations in the gas plume, in combination with bad meteorological conditions require the development of novel methods to derive reliable flux estimates. In this presentation we will discuss the instrumental issues and present the latest version of the emission estimates made from our measurements.}, subject = {Vulkanismus}, language = {en} } @inproceedings{WeberEliassonArnasonetal.2015, author = {Weber, Konradin and Eliasson, Jonas and Arnason, Gylfi and R{\"o}gnvaldsson, {\´O}lafur and Thorsteinsson, Throstur and Palsson, Thorgeir and B{\"o}hlke, Christoph and Fischer, Christian and Smith, Paul and Jones, Roderic L. and Tirpitz, Lukas and Platt, Ulrich}, title = {Airborne Investigations and WRF - Model Calculations of the Bardarbunga-Holuhraun Eruption Plume}, series = {Geophysical Research Abstracts: EGU General Assembly 2015}, volume = {17}, booktitle = {Geophysical Research Abstracts: EGU General Assembly 2015}, publisher = {Copernicus}, address = {G{\"o}ttingen}, year = {2015}, abstract = {The eruption in Holuhraun is the largest producer of lava and gas in Iceland since 1783. The Volcanic Ash Research (VAR) group organized an airborne measurement campaign including 10 flights, where emissions of SO2 and ash concentrations were measured at the source and at the far plume. The highest SO2 concentration at the source was nearly up to 100 mg/m3. This is an extremely high value, compared to other airborne campaigns and a contamination considered to cause serious illness by the Icelandic Directorate of Health. Volcanic ash consisted of very fine particles, but the concentration was low when compared to other recent eruptions. Measurements of the far plume showed that scavenging is very active. The dispersion was successfully modeled with the Weather Research and Foreast (WRF-chem) model and analysis using the model showed that a large amount of the sulphur was precipitated in the Icelandic highlands.}, subject = {Vulkanismus}, language = {en} } @article{EliassonYoshitaniWeberetal.2014, author = {Eliasson, Jonas and Yoshitani, Junichi and Weber, Konradin and Yasuda, Nario and Iguchi, Masato and Vogel, Andreas}, title = {Airborne Measurement in the Ash Plume from Mount Sakurajima: Analysis of Gravitational Effects on Dispersion and Fallout}, series = {International Journal of Atmospheric Sciences}, volume = {2014}, journal = {International Journal of Atmospheric Sciences}, publisher = {Wiley}, issn = {2314-4122}, doi = {10.1155/2014/372135}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-50955}, pages = {16}, year = {2014}, abstract = {Volcanic ash concentrations in the plume from Sakurajima volcano in Japan are observed from airplanes equipped with optical particle counters and GPS tracking devices. The volcano emits several puffs a day. The puffs are also recorded by the Sakurajima Volcanological Observatory. High concentrations are observed in the puffs and fallout driven by vertical air current, called streak fallout. Puffs dispersion is analyzed by the classical diffusion-advection method and a new gravitational dispersion method. The fluid mechanic of the gravitational dispersion, streak fallout, and classical diffusion-advection theory is described in three separate appendices together with methods to find the time gravitational dispersion constant and the diffusion coefficient from satellite photos. The diffusion-advection equation may be used to scale volcanic eruptions so the same eruption plumes can be scaled to constant flux and wind conditions or two eruptions can be scaled to each other. The dispersion analyses show that dispersion of volcanic plumes does not follow either theories completely. It is most likely diffusion in the interface of the plume and the ambient air, together with gravitational flattening of the plumes core. This means larger boundary concentration gradients and smaller diffusion coefficients than state of the art methods can predict.}, subject = {Vulkanismus}, language = {en} } @article{MaginKoestersJanduraetal.2025, author = {Magin, Melanie and K{\"o}sters, Raphael and Jandura, Olaf and Weiß, Ralph and Stark, Birgit and Udris, Linards and Klein, Miriam and Riedl, Andreas A.}, title = {Viewpoint Diversity, Balance, Deliberativeness: Assessing the Media Performance of Migration Coverage Multi-Dimensionally Based on Deliberative Democratic Theories}, series = {Mass Communication and Society}, journal = {Mass Communication and Society}, publisher = {Informa}, issn = {1520-5436}, doi = {10.1080/15205436.2025.2461082}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-51020}, pages = {25}, year = {2025}, abstract = {The issue of migration is highly salient in public debates in many countries. Given this salience and the risk of political instrumentalization, often by actors from the far right, it is important for citizens to receive high-quality, differentiated information on the migration issue. This touches upon the question of media performance. While there is abundant research on the media portrayal of the migration issue, this research strand is, surprisingly, hardly linked to research on media performance. We establish this link and present an innovative, sophisticated framework for standardized content analyses on migration. It combines three standards of media performance that are key to deliberative democratic theories—viewpoint diversity, balance, and deliberativeness—and utilizes value frames and the sociological concept of idea elements to measure viewpoint diversity and balance. A first empirical test of our newly developed approach, taking Germany as a case, shows noticeable differences in the media performance of 11 outlets analyzed. This test proves the applicability of our framework, which provides a valuable starting point for future comparative research on the media performance of migration coverage across countries and over time.}, subject = {Meinungsvielfalt}, language = {en} } @inproceedings{WeberFischerVogeletal.2013, author = {Weber, Konradin and Fischer, Christian and Vogel, Andreas and Pohl, Tobias and B{\"o}hlke, Christoph and Lau, Hendrik and Eliasson, Jonas and Palsson, Thorgeir}, title = {First results of an airborne release of volcanic ash for testing of volcanic ash plume measurement instruments}, series = {Recent Advances in Energy and Environmental Management}, volume = {Energy, Environmental and Structural Engineering Series 13}, booktitle = {Recent Advances in Energy and Environmental Management}, editor = {Mladenov, Valeri and Tasho, Tashev and Hui, Wang and Ivan, Kralov and Sergey, Stankevich and Pelin, Yildiz and Jon, Burley}, publisher = {WSEAS}, pages = {169 -- 172}, year = {2013}, subject = {Vulkanasche}, language = {en} } @inproceedings{RopertzLampDouardetal.1997, author = {Ropertz, Alexander and Lamp, Torsten and Douard, Mathilde and Weber, Konradin and Gaertner, Andrea and Elbers, C. and Nitz, R.}, title = {Calibration of a high-resolution open-path FTIR spectrometer combined with an adjustable 100-m multipass cell}, series = {SPIE Proceedings, Remote Sensing of Vegetation and Water, and Standardization of Remote Sensing Methods}, volume = {3107}, booktitle = {SPIE Proceedings, Remote Sensing of Vegetation and Water, and Standardization of Remote Sensing Methods}, editor = {Cecchi, Giovanna and Lamp, Torsten and Reuter, Rainer and Weber, Konradin}, publisher = {SPIE}, issn = {0277-786X}, doi = {10.1117/12.274749}, pages = {137 -- 147}, year = {1997}, subject = {FT-IR-Spektroskopie}, language = {en} } @inproceedings{WeberEickel1997, author = {Weber, Konradin and Eickel, Karl-Heinz}, title = {Standardization of open-path FTIR measurements in Germany}, series = {SPIE Proceedings, Remote Sensing of Vegetation and Water, and Standardization of Remote Sensing Methods}, volume = {3107}, booktitle = {SPIE Proceedings, Remote Sensing of Vegetation and Water, and Standardization of Remote Sensing Methods}, editor = {Cecchi, Giovanna and Lamp, Torsten and Reuter, Rainer and Weber, Konradin}, publisher = {SPIE}, issn = {0277-786X}, doi = {10.1117/12.274753}, pages = {174 -- 176}, year = {1997}, subject = {FT-IR-Spektroskopie}, language = {en} } @article{GeneralBobrowskiPoehleretal.2015, author = {General, S. and Bobrowski, N. and P{\"o}hler, D. and Weber, Konradin and Fischer, C. and Platt, U.}, title = {Airborne I-DOAS measurements at Mt. Etna: BrO and OClO evolution in the plume}, series = {Journal of Volcanology and Geothermal Research}, volume = {300}, journal = {Journal of Volcanology and Geothermal Research}, publisher = {Elsevier}, issn = {0377-0273}, doi = {10.1016/j.jvolgeores.2014.05.012}, pages = {175 -- 186}, year = {2015}, language = {en} } @article{EliassonYasudaWeberetal.2014, author = {Eliasson, Jonas and Yasuda, Nario and Weber, Konradin and Vogel, Andreas and Palsson, Thorgeir}, title = {The role of in-situ measurements of volcanic ash concentrations in preventing economic disasters due to volcanic ash clouds}, series = {Journal of Integrated Disaster Risk Management}, volume = {4}, journal = {Journal of Integrated Disaster Risk Management}, number = {1}, publisher = {Journal of Integrated Disaster Risk Management}, issn = {2185-8322}, doi = {10.5595/idrim.2014.0092}, pages = {48 -- 60}, year = {2014}, language = {en} } @inproceedings{WeberVogelReichardtetal.2012, author = {Weber, Konradin and Vogel, Andreas and Reichardt, Roland and Zimmermann, Thomas}, title = {Research aircraft flight for gas leakage investigation at the Elgin wellhead gas platform in the North Sea - initial results}, series = {Recent Researches in Environmental and Geological Sciences}, booktitle = {Recent Researches in Environmental and Geological Sciences}, editor = {Altawell, Najib and Konstantin, Volkov and Cristina, Matos and Fernandez de Arroyabe, Pablo}, publisher = {WSEAS}, pages = {240 -- 243}, year = {2012}, subject = {Forschungsflugzeug}, language = {en} } @inproceedings{VogelWeberFischeretal.2012, author = {Vogel, Andreas and Weber, Konradin and Fischer, Christian and Prata, A. J. and Durant, A. J.}, title = {Aircraft in situ and remote sensing measurements of emissions from Etna volcano, Sicily}, series = {Geophysical Research Abstracts: EGU General Assembly 2012}, booktitle = {Geophysical Research Abstracts: EGU General Assembly 2012}, publisher = {Copernicus}, address = {G{\"o}ttingen}, year = {2012}, abstract = {Volcanoes emit particles (silicates and sulphate aerosol) and gases (e.g., water and sulphur dioxide) which influence the radiative balance of the atmosphere. The rate at which sulphur dioxide oxidises to sulphate aerosol is poorly constrained and measurements of downwind abundance are required to quantify the rate at which this process occurs. During July and November 2011, a series of measurements were performed in emissions from Etna Volcano, Sicily, using the University of Applied Sciences (Dusseldorf) research aircraft. Both in situ and remote sensing instrumentation was simultaneously deployed to quantify the down-wind characteristics of gases and particles in the plume emitted by the volcano. In situ particle characteristics were measured using a Grimm 1.109 optical particle counter (microparticles 0.25-32 microns) and Grimm 1320 diffusion electrometer (nanoparticles 25-300 nanometers). Column abundance of sulphur dioxide was measured using a vertically-pointing differential optical absorption spectrometer (DOAS). These measurements were compared to horizontal pathlength-integrated measurements of sulphur dioxide from the Airborne Volcanic Imaging Object Detector (AVOID). Down-wind plume dispersion was discriminated through a series of aircraft transects below and through the volcanic plume. The emissions contained large amounts of nanoparticles relative to microparticles, which reflects gas-phase nucleation of sulphate aerosol. The AVOID system discriminated horizontal layering of volcanic aerosol at altitudes of up to 12,000 ft from a detection range of >50 km. Plume boundaries were discriminated using a combination of the in situ and DOAS measurements in order to compare to the pathlength-integrated measurements from AVOID.}, subject = {Forschungsflugzeug}, language = {en} } @inproceedings{DeckertMohya2023, author = {Deckert, Carsten and Mohya, Ahmed}, title = {Tinkering, Tools and Techniques - Creativity in German Engineering Education}, series = {AIJR Proceedings: Proceedings of the 14th European Conference on Creativity in Innovation}, booktitle = {AIJR Proceedings: Proceedings of the 14th European Conference on Creativity in Innovation}, editor = {Heijne, Katrina}, publisher = {AIJR Publisher}, issn = {2582-3922}, doi = {10.21467/proceedings.154.2}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-51142}, pages = {11 -- 18}, year = {2023}, abstract = {Purpose - Engineers are expected to be the creative problem solvers and innovative tinkerers of a company. This article examines to what extent German tertiary education lives up to this expectation. The analysis of German module descriptions in engineering shows that there are no courses dedicated to creativity and that creativity and its techniques are mentioned only sparsely in the modules of the engineering curriculum. Surveys amongst our students show that they are usually familiar with techniques which are based on generating alternatives such as brainstorming and morphological box, but lack knowledge about techniques based on challenging assumptions such as forced connection. They tend to favour discursive techniques over intuitive ones and techniques which use generation of alternatives as an idea-generating principle. A combination of creativity techniques seems to be most conducive to creative output in our course. Finally, we present some first findings on creative sessions in remote work with the help of virtual whiteboards, which have gained in importance since the pandemic. Methodology - Firstly, we present an document analysis of the modules of Bachelor and Master programs of mechanical engineering at German universities and universities of applied sciences. Secondly, we present results from surveys in our Master course in "Innovation and Technology Management" where we gathered data from students over several years and performed an external evaluation of the output using Consensual Assessment Technique (CAT). These results include which creativity techniques the students know prior to the course and which they prefer as well as which techniques seem to be conducive to engineering creativity. Furthermore we surveyed their experiences with creative sessions as remote work. Conclusion - Overall, the article shows the importance to teach prospective engineers the basics in creativity. Students should have the opportunity to acquire knowledge about and apply different creativity techniques, as different techniques have different strengths and weaknesses and, thus, different areas of fruitful application. They should also have the chance to try out different modes such as in-person sessions and virtual sessions, as some of the future work will most likely shift online. Furthermore, a combination of different creativity techniques makes it more likely that engineers break through their usual systematic-analytic way of thinking and helps them to think outside the box to find creative solutions for the pressing problems of our time.}, subject = {Ingenieurstudium}, language = {en} } @incollection{Deckert2023, author = {Deckert, Carsten}, title = {Sustainable Logistics}, series = {Encyclopedia of Sustainable Management}, booktitle = {Encyclopedia of Sustainable Management}, publisher = {Springer Nature}, address = {Cham}, isbn = {9783031259838}, doi = {10.1007/978-3-031-25984-5_131}, pages = {3562 -- 3566}, year = {2023}, language = {en} } @incollection{Deckert2023, author = {Deckert, Carsten}, title = {Supply Chain}, series = {Encyclopedia of Sustainable Management}, booktitle = {Encyclopedia of Sustainable Management}, publisher = {Springer Nature}, address = {Cham}, isbn = {9783031259838}, doi = {10.1007/978-3-031-25984-5_132}, pages = {3212 -- 3214}, year = {2023}, language = {en} } @inproceedings{DeckertMohya2023, author = {Deckert, Carsten and Mohya, Ahmed}, title = {Teaching Sustainable Logistics As A Project-Based Learning Course}, series = {European Society for Engineering Education (SEFI), 11-14 September 2023, TUDublin, Ireland}, booktitle = {European Society for Engineering Education (SEFI), 11-14 September 2023, TUDublin, Ireland}, publisher = {TU Dublin}, address = {Dublin}, doi = {10.21427/9D3F-KA64}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-51182}, year = {2023}, abstract = {Sustainable logistics combines the task of the 6R of logistics (right product, right place, right time, right condition, right cost) with social and environmental sustainability, especially low emissions and low resource consumption. This means that a problem that is already challenging, namely planning, executing, and controlling logistical processes, gets even more complex and requires aspects of systems thinking to incorporate environmental and social impacts. Classical approaches of teaching, e.g. lectures with presentations and short exercises on closed problems, do not do justice to the complexity and intricacies of the topic sustainability. In such a context, projectbased learning (PBL) where students do group work on open-ended problems with real-world complexity seems to be a more adequate means to teach the subject. The paper describes a PBL course in which students worked on projects to conceptualize micro-depots for parcel delivery in different areas of D{\"u}sseldorf. A micro-depot is a temporary storage location in a city from which parcels can be delivered by cargo bikes. The aim was to locate the micro-depot, design the delivery routes, check the feasibility, and calculate the reduction of greenhouse gases and other emissions. The course was taught in cooperation with a partner from the courier, express, and parcel delivery industry. The paper describes the experiences with the course and gives recommendations for a successful implementation of PBL in courses on sustainability.}, subject = {Ingenieurstudium}, language = {en} } @inproceedings{LampWeberWeidemannetal.1994, author = {Lamp, Torsten and Weber, Konradin and Weidemann, Johannes and van Haren, Guenther}, title = {Application of FTIR spectroscopy to open-path measurements at industrial sites in Germany}, series = {SPIE Proceedings, Optical Sensing for Environmental and Process Monitoring}, volume = {2365}, booktitle = {SPIE Proceedings, Optical Sensing for Environmental and Process Monitoring}, editor = {Simpson, Orman A.}, publisher = {SPIE}, issn = {0277-786X}, doi = {10.1117/12.210782}, pages = {6 -- 14}, year = {1994}, subject = {FT-IR-Spektroskopie}, language = {en} } @inproceedings{WeberWeidemannvanHarenetal.1995, author = {Weber, Konradin and Weidemann, Johannes and van Haren, Guenther and Lamp, Torsten}, title = {Open-path FTIR measurements at an urban area in Germany}, series = {SPIE Proceedings, Optical Sensing for Environmental and Process Monitoring}, volume = {2365}, booktitle = {SPIE Proceedings, Optical Sensing for Environmental and Process Monitoring}, editor = {Simpson, Orman A.}, publisher = {SPIE}, issn = {0277-786X}, doi = {10.1117/12.210818}, pages = {37 -- 46}, year = {1995}, subject = {FT-IR-Spektroskopie}, language = {en} } @article{KuttlerLampWeber2002, author = {Kuttler, Wilhelm and Lamp, Torsten and Weber, Konradin}, title = {Summer air quality over an artificial lake}, series = {Atmospheric Environment}, volume = {36}, journal = {Atmospheric Environment}, number = {39-40}, publisher = {Elsevier}, issn = {1352-2310}, doi = {10.1016/S1352-2310(02)00776-8}, pages = {5927 -- 5936}, year = {2002}, subject = {Luftqualit{\"a}t}, language = {en} } @inproceedings{WeidauerEickelLahmannetal.1998, author = {Weidauer, Derk and Eickel, Karl-Heinz and Lahmann, Wilhelm and Nikowa, Ljuba and Ulbricht, Matthias and Weber, Konradin and Weitkamp, Claus and Wolf, Jean-Pierre}, title = {Standardization of DAS lidar measurements}, series = {Nineteenth International Laser RadarConference}, booktitle = {Nineteenth International Laser RadarConference}, editor = {Singh, Upendra N. and Syed, Ismail and Geary K., Schwemmer}, publisher = {National Aeronautics and Space Administration}, address = {Hampton, VA}, pages = {771}, year = {1998}, subject = {Lidar}, language = {en} } @inproceedings{DouardZeutziusReitzLampetal.1997, author = {Douard, Mathilde and Zeutzius-Reitz, Juergen and Lamp, Torsten and Ropertz, Alexander and Weber, Konradin}, title = {Quality-assurance procedures and measurements for open-path FTIR spectroscopy}, series = {SPIE Proceedings, Remote Sensing of Vegetation and Water, and Standardization of Remote Sensing Methods}, volume = {3107}, booktitle = {SPIE Proceedings, Remote Sensing of Vegetation and Water, and Standardization of Remote Sensing Methods}, editor = {Cecchi, Giovanna and Lamp, Torsten and Reuter, Rainer and Weber, Konradin}, publisher = {SPIE}, issn = {0277-786X}, doi = {10.1117/12.274747}, pages = {114 -- 125}, year = {1997}, subject = {FT-IR-Spektroskopie}, language = {en} } @inproceedings{LampRadmacherWeberetal.1997, author = {Lamp, Torsten and Radmacher, M. and Weber, Konradin and Gaertner, Andrea and Nitz, R. and Broeker, G.}, title = {Calibration of an open-path FTIR spectrometer for methane, ethylene, and carbon monoxide using a fixed 20-m multipass cell}, series = {SPIE Proceedings, Remote Sensing of Vegetation and Water, and Standardization of Remote Sensing Methods}, volume = {3107}, booktitle = {SPIE Proceedings, Remote Sensing of Vegetation and Water, and Standardization of Remote Sensing Methods}, editor = {Cecchi, Giovanna and Lamp, Torsten and Reuter, Rainer and Weber, Konradin}, publisher = {SPIE}, issn = {0277-786X}, doi = {10.1117/12.274748}, pages = {126 -- 136}, year = {1997}, subject = {FT-IR-Spektroskopie}, language = {en} } @inproceedings{PohlWeberFischeretal.2019, author = {Pohl, Tobias and Weber, Konradin and Fischer, Christian and Kramer, Tim}, title = {Investigation of the Temporal and Spatial Distribution of Ultrafine Particles with Stationary and Mobile Measurements at the International Airport in Duesseldorf}, series = {European Aerosol Conference 2019, 25.-30. August 2019, Gothenburg, Sweden}, booktitle = {European Aerosol Conference 2019, 25.-30. August 2019, Gothenburg, Sweden}, year = {2019}, subject = {Feinstaub}, language = {en} } @inproceedings{WeberKramerFischeretal.2019, author = {Weber, Konradin and Kramer, Tim and Fischer, Christian and Pohl, Tobias and B{\"o}hlke, Christoph}, title = {Evaluation of low cost and mid cost sensors for fine particulate matter at urban sites}, series = {Geophysical Research Abstracts: EGU General Assembly 2019}, volume = {21}, booktitle = {Geophysical Research Abstracts: EGU General Assembly 2019}, publisher = {Copernicus}, address = {G{\"o}ttingen}, year = {2019}, abstract = {High ambient air concentrations of fine particulate matter are a problem in many European cities, especially in traffic loaded street canyons. Therefore, the introduction of traffic restricted or traffic reduced areas is discussed as a countermeasure in several towns. However, at that point it is not always clear, in what extent the restriction of traffic in presently overloaded streets causes the exceeding of limit values in other areas of the town after the redirection of the traffic. Presently this cannot be recorded appropriately, when the concentrations of fine particulate matter are monitored only at rarely distributed single points by the official measurement systems of the environmental state agencies. On the other hand, meanwhile there are low cost and mid cost sensors for the measurement of fine particulate matter available, which enable the parallel monitoring with many measurement systems in an extended area of the town. By this way, the effect of traffic restrictions on the distribution of fine particulate matter in the city can potentially be observed. However, at this point the question arises, how reliable the results are, which are delivered by the low and mid cost sensors for fine particulate matter. For this reason different low cost and mid cost sensors have been evaluated for this study and intercompared with certified reference measurement systems for fine particulate matter. The study comprised the sensors SDS011 (Nova Fitness), which is in use already for several citizen science projects in Germany, SPS30 (Sensirion), OPC-R1 (Alphasense), OPC-N2 (Alphasense) and OPC-N3 (Alphasense). This study was performed at urban sites in D{\"u}sseldorf (Germany) for several weeks and covered different traffic loads and different meteorological situations, in order to get representative results. As atmospheric humidity can influence the measurement results, the humidity was measured in parallel to the fine particulate matter. It could be shown that the validity of the measurement results of fine particulate matter could be improved, when the parallel readings of the humidity were taken into account.}, subject = {Messtechnik}, language = {en} } @inproceedings{WeberThielkeFischer2019, author = {Weber, Konradin and Thielke, Jan and Fischer, Christian}, title = {Evaluation of selected physical parameters measured with smartphones}, series = {Verhandlungen der Deutschen Physikalische Gesellschaft e.V.}, booktitle = {Verhandlungen der Deutschen Physikalische Gesellschaft e.V.}, publisher = {Deutsche Physikalische Gesellschaft e.V.}, address = {Bad Honnef}, year = {2019}, subject = {Messtechnik}, language = {en} } @inproceedings{WeberKramerFischeretal.2018, author = {Weber, Konradin and Kramer, Tim and Fischer, Christian and Pohl, Tobias and Schulenberg, Malte and Heweling, Georg and B{\"o}hlke, Christoph}, title = {Testing and evaluation of low-cost sensors for fine particulate matter PM10 and PM2.5}, series = {Geophysical Research Abstracts: EGU General Assembly 2018}, volume = {20}, booktitle = {Geophysical Research Abstracts: EGU General Assembly 2018}, publisher = {Copernicus}, address = {G{\"o}ttingen}, year = {2018}, abstract = {It is well known from medical studies that fine particulate matter has adverse effects to human health. However, exceeding of limit values for fine particulate matter PM10 and PM2.5 is still a problem in major German cities. Therefore, fine particulate matter is monitored in Germany by environmental state agencies at fixed stations with certified instruments. These certified instruments are able to deliver reliable and high quality results. However, because of the costs of these certified instruments and the maintenance efforts, only few measurements stations are placed in the cities at places, which are regarded as representative for the air pollution. On the other hand, it is of interest to know the concentration of fine particulate matter in areas and at places, which are not covered by the fixed measurement stations of the environmental state agencies. In this situation citizen science projects started in Germany using low cost sensors for fine particulate matter. In principle, with these low cost sensors citizens could measure fine particulate matter at places and in situations of their interests. However, at that point the question of reliability of the low cost sensor data arises. Therefore the Duesseldorf University of Applied Sciences (HSD) in Germany started a project for the testing and evaluation of low-cost sensors. For this reason 20 low-cost sensor units have been built up based on the SDS 011 sensor of Nova Fitness Inc. within the Laboratory for Environmental Measurement Techniques at HSD. The sensor measurement data can be transferred into a network and can be visualized on a digital map. This testing and evaluation at HSD of the low-cost sensors comprised: • Short term and long term comparison studies within the laboratory and at different urban sites with a certifiedwide range aerosol measurement system (Grimm WRAS). • Short term and long term comparison studies within the laboratory and at different urban sites with mid-cost sensors (Alphasense AN2). • Intercomparison testing and evaluation of sensors of the same production charge. • Intercomparison testing and evaluation of sensors of different production charges. • Testing and evaluation of the sensors at different meteorological conditions. The results of this testing and evaluation will be presented at the conference. Moreover, the potential of additional applications for low-cost sensors, e.g. for mobile measurements (multicopter UAS, bicycles, pedestrians) or for the validation of air pollution models, will be discussed}, subject = {Messtechnik}, language = {en} } @inproceedings{WeberFischerLangeetal.2017, author = {Weber, Konradin and Fischer, Christian and Lange, Martin and Schulz, Uwe and Naraparaju, Ravisankar and Kramer, Dietmar}, title = {Design and construction of a testbed for the application of real volcanic ash from the Eyjafjallaj{\"o}kull and Grimsv{\"o}tn eruptions to microgas turbines}, series = {Geophysical Research Abstracts: EGU General Assembly 2017}, volume = {19}, booktitle = {Geophysical Research Abstracts: EGU General Assembly 2017}, publisher = {Copernicus}, address = {G{\"o}ttingen}, year = {2017}, abstract = {It is well known that volcanic ash clouds emitted from erupting volcanoes pose a considerable threat to the aviation. The volcanic ash particles can damage the turbine blades and their thermal barrier coatings as well as the bearings of the turbine. For a detailed investigation of this damaging effect a testbed was designed and constructed, which allowed to study the damaging effects of real volcanic ash to an especially for these investigations modified microgas turbine. The use of this microgas turbine had the advantage that it delivers near reality conditions, using kerosene and operating at similar temperatures as big turbines, but at a very cost effective level. The testbed consisted out of a disperser for the real volcanic ash and all the equipment needed to control the micro gas turbine. Moreover, in front and behind the microgas turbine the concentration and the distribution of the volcanic ash were measured online by optical particle counters (OPCs). The particle concentration and size distribution of the volcanic ash particles in the intake in front of the microgas turbine was measured by an optical particle counter (OPC) combined with an isokinetic intake. Behind the microgas turbine in the exhaust gas additionally to the measurement with a second OPC ash particles were caught with an impactor, in order to enable the later analysis with an electron microscope concerning the morphology to verify possible melting processes of the ash particles. This testbed is of high importance as it allows detailed investigations of the impact of volcanic ash to jet turbines and appropriate countermeasures.}, subject = {Vulkanismus}, language = {en} } @inproceedings{WeberScharifiFischeretal.2017, author = {Weber, Konradin and Scharifi, Emad and Fischer, Christian and Pohl, Tobias and Lange, Martin and B{\"o}hlke, Christoph}, title = {Mobile measurements of air pollutants with an instrumented car in populated areas}, series = {Geophysical Research Abstracts: EGU General Assembly 2017}, volume = {19}, booktitle = {Geophysical Research Abstracts: EGU General Assembly 2017}, publisher = {Copernicus}, address = {G{\"o}ttingen}, year = {2017}, abstract = {Detailed mobile measurement of gases and fine particulate matter has been reported in the literature to be suitable to exhibit the air pollutants concentration in populated areas. This concentration is linked to the increase of number of cars, construction areas, industries and other emission sources. However, fixed measurement stations, mostly operated by environmental agencies, are limited in numbers and cannot cover a large area in monitoring. For this reason, to overcome this drawback, mobile measurements of the variability of gases (such as O3, NO, NO2) and particulate matter concentration were carried out during this study using an instrumented car. This car was able to deliver measurement results of all these compounds in a large area. The experimental results in this work demonstrate a large spatial variability of gases and fine particulate matters mainly depended on the traffic density and the location. These effects are especially obvious in the city core and the high traffic roads. In terms of fine particulate matter, this becomes evident for PM 10 and PM 2.5, where the mass and number concentration increases with arriving these zones.}, subject = {Messtechnik}, language = {en} } @inproceedings{WeberHewelingFischeretal.2017, author = {Weber, Konradin and Heweling, Georg and Fischer, Christian and Lange, Martin and B{\"o}hlke, Christoph}, title = {Octocopter investigation of the vertical and horizontal variation of ultrafine particles, fine particulate matter and soot in the traffic plume emitted from a Rhine river bridge in Duesseldorf, Germany}, series = {Geophysical Research Abstracts: EGU General Assembly 2017}, volume = {19}, booktitle = {Geophysical Research Abstracts: EGU General Assembly 2017}, publisher = {Copernicus}, address = {G{\"o}ttingen}, year = {2017}, abstract = {For this study an octocopter UAV was used for carrying an ultrafine (UFP) particle monitor, an optical particle counter (OPC) and a micro aethalometer. The UFP-monitor, based on electrical charging of UFPs, was able to count the number of UFPs and give an estimated mean diameter of the measured particles. The OPC, based on the particle induced light scattering of a laser beam, was able to detect aerosols in a size range of about 250 nm to 32 μm in 31 bins. The micro aethalometer measured the soot by optical attenuation of a light beam which is caused by carbon particulate matter. The octocopter with a lift off weight by 10.5 kg was especially designed and constructed at the University of Applied Sciences, Duesseldorf, for the measurement of air pollutants. It was equipped with eight 900 W electric engines and a pixhawk flight control. Technically this octocopter was able to climb up to altitudes of up to 2 km AGL. However, during this study an altitude range of several 10 meters was used. During this study about 60 octocopter flights were performed. The flights clearly revealed a plume of UFPs coming from the traffic on the bridge. This result was confirmed by various upwind and downwind measurements with the octocopter in the region of the bridge.}, subject = {Messtechnik}, language = {en} } @inproceedings{EliassonPalssonWeber2017, author = {Eliasson, Jonas and Palsson, Thorgeir and Weber, Konradin}, title = {State of volcanic ash dispersion prediction}, series = {Geophysical Research Abstracts: EGU General Assembly 2017}, booktitle = {Geophysical Research Abstracts: EGU General Assembly 2017}, publisher = {Copernicus}, address = {G{\"o}ttingen}, year = {2017}, abstract = {The Eyjafjallajokull 2010 and Grimsvotn 2011 eruptions created great problems for commercial aviation in Western Europe and in the North Atlantic region. Comparison of satellite images of the visible and predicted ash clouds showed the VAAC prediction to be much larger than the actual ash clouds. No official explanation of this discrepancy exists apart from the definition of the ash cloud boundary. Papers on simulation of the Eyjafjallaj{\"o}kull ash cloud in peer reviewed journals, typically attempted to simulate the VAAC predictions rather than focusing on the satellite pictures. Sporadic measurements made in-situ showed much lower ash concentrations over Europe than the predicted values. Two of the weak points in ash cloud prediction have been studied in airborne measurements of volcanic ash by the Universities in Kyoto Japan, Iceland and D{\"u}sseldorf Germany of eruptions in Sakurajima, Japan. It turns out that gravitational deformation of the plume and a streak fallout process make estimated ash content of clouds larger than the actual, both features are not included in the simulation model. Tropospheric plumes tend to ride in stable inversions this causes gravitational flattening (pancaking) of the volcanic plume, while diffusion in the mixing layer is insignificant. New rules from ICAO, effective from November 2014, reiterate that jetliners should avoid visible ash, this makes information on visible ash important. A procedure developed by JMA′s Tokyo VAAC uses satellite images of visible ash to correct the prediction. This and the fact that meteorological data necessary to model gravitational dispersion and streak fallout do not exist in the international database available to the VAAC′s. This shows that close monitoring by airborne measurements and satellite and other photographic surveillance is necessary.}, subject = {Vulkanismus}, language = {en} } @inproceedings{WeberScharifiBoehlke2015, author = {Weber, Konradin and Scharifi, Emad and B{\"o}hlke, Christoph}, title = {Mobile measurements of the horizontal variation of fine particulate matter in the state of North Rhine Westphalia in Germany - a case study}, series = {Recent Advances on Environmental and Life Science}, volume = {Energy, Environmental and Structural Engineering Series 40}, booktitle = {Recent Advances on Environmental and Life Science}, editor = {Bulucea, Aida}, publisher = {WSEAS}, isbn = {978-1-61804-332-0}, issn = {2227-4359}, pages = {22 -- 27}, year = {2015}, abstract = {Fine particulate matter is well known for its adverse health effects for the population. It is still one of the major problems of air pollution in Germany. The limit values of fine particulate matter PM10 are often exceeded in bigger German cities. Therefore the level of fine particulate matter and other air pollutants are routinely monitored at single hot spots in the cities by measurement stations of the environmental state agencies. However, it is of high interest, what levels of concentrations of fine particulate matter are to be found in those areas, where no measurement stations are placed. Moreover, it is important to know, how strong exceedings of fine particulate matter concentrations can be influenced by meteorological conditions. In this paper fine particulate matter concentrations are measured with a car, which was equipped with measurement systems for fine particulate matter and which was driving through industrial and rural areas of the state North Rhine Westphalia in Germany. By this means it was possible to measure coarse and fine fractions of particulate matter continuously during driving. In this way the horizontal variation of fine particulate matter could be investigated throughout the state. The measurements comprised dust concentrations of the fractions PM10 (coarse), PM2.5 (more fine) and PM1(very fine), which are addressed within the European environmental legislation. Moreover, every second during driving the full size distribution of particles between 250 nm and 32 μm diameter was measured. Therefore it could be investigated, at what places more bigger or more smaller particles were present under specific meteorological conditions. The mobile car measurements were performed as a case study in a situation with a strong meteorological inversion layer. The mobile measurements of the horizontal variation of fine particulate matter in industrial and rural areas are compared with model prediction calculations. Moreover, using backward trajectories a source appointment of the fine particulate matter could be performed.}, subject = {Feinstaub}, language = {en} } @inproceedings{WeberPohlFischeretal.2015, author = {Weber, Konradin and Pohl, Tobias and Fischer, Christian and Lange, Martin and B{\"o}hlke, Christoph}, title = {Determination of a Vertical Profile of Black Carbon by a Combined Application of a Light Research Aircraft and a Quadcopter Unmanned Aerial Vehicle - A Case Study Using an Airborne Ultraportable Micro-Aethalometer for Black Carbon Measurements at a Rural Site in Germany}, series = {Recent Researches in Electrical and Computer Engineering}, volume = {Recent Advances in Electrical Engineering Series 49}, booktitle = {Recent Researches in Electrical and Computer Engineering}, editor = {Valeri, Mladenov}, publisher = {WSEAS}, isbn = {978-1-61804-315-3}, issn = {1790-5117}, pages = {13 -- 18}, year = {2015}, subject = {Messtechnik}, language = {en} } @inproceedings{WeberFischerLangeetal.2015, author = {Weber, Konradin and Fischer, Christian and Lange, Martin and Pohl, Tobias and B{\"o}hlke, Christoph and Wagner, Frank and Mattis, Ina and Flentje, Harald and Sturm, Klaus and Barth, Joachim and Steinkopff, Thomas and Vogel, Andreas}, title = {Aircraft measurements compared with ceilometer measurements during a sahara dust period in Germany}, series = {Geophysical Research Abstracts: EGU General Assembly 2015}, volume = {17}, booktitle = {Geophysical Research Abstracts: EGU General Assembly 2015}, publisher = {Copernicus}, address = {G{\"o}ttingen}, year = {2015}, abstract = {A significant Sahara dust event took place at the beginning of April 2014 over large areas of Germany and Europe. The German Weather Service (DWD) detected and monitored the expansion and propagation of this dust cloud with a ceilometer network of more than 50 ceilometers. Moreover, these ceilometers were also able to track the altitude of the dust cloud at the positions of the ceilometers. Additionally, aircraft measurements over Germany and France were performed with two aircraft by the Duesseldorf University of Applied Sciences. These aircraft were equipped with optical particle counters (OPC) and were able to measure the particle size distribution within the Sahara dust cloud and as a result of this to calculate the particle mass concentration of the dust. The ceilometer measurements and the aircraft measurements complemented each other: whereas the ceilometers gave continuous information about the Sahara dust cloud at the ceilometer positions, the aircraft measurements delivered interpolating results between the ceilometer positions. Moreover, at several ceilometer positions intercomparison flights were performed by spiraling with the aircraft up or down around the ceilometer laser beam. This gave the unique possibility for comparing the remote sensing results of the ceilometers with the in-situ measurements of the aircraft. This study shows that a significant high amount of Saharan dust particles was transported over Germany during a several days long episode. Furthermore, the intercomparison study between the German ceilometer network and aircraft measurements results shows a good agreement. A combination of these techniques could help to detect the vertical and horizontal distribution of the dust cloud and additionally the particle mass concentration.}, subject = {Deutscher Wetterdienst}, language = {en} } @inproceedings{ArnasonEliassonWeberetal.2015, author = {Arnason, Gylfi and Eliasson, Jonas and Weber, Konradin and B{\"o}hlke, Christoph and Palsson, Thorgeir and R{\"o}gnvaldsson, {\´O}lafur and Thorsteinsson, Throstur and Platt, Ulrich and Tirpitz, Lukas and Jones, Roderic L. and Smith, Paul D.}, title = {Results of airborne measurements in the plume near and far from the 2014 Bardarbunga-Holuhraun eruption}, series = {Geophysical Research Abstracts: EGU General Assembly 2015}, volume = {17}, booktitle = {Geophysical Research Abstracts: EGU General Assembly 2015}, publisher = {Copernicus}, address = {G{\"o}ttingen}, year = {2015}, abstract = {The Volcanic Ash Research (VAR) group is focused on airborne measurement of ash contamination to support safe air travel. In relations to the recent eruption, the group measured ash and several gaseous species in the plume 10-300 km from the volcano. The eruption emitted ash turned out to be mostly in the fine aerosol range (much less than 10 micrometers in diameter). Our highest measured concentrations were lower than 1 mg/m3 indicating that commercial air traffic was not threatened (greater than 2 mg/m3) by the ash contamination. But we measured sulfur dioxide (SO2 ) up to 90 mg/m3, which presented a potentially dangerous pollution problem. However, airborne measurements indicate that the sulfur concentration decays (probably due to scavenging) as the plume is carried by the wind from the volcano, which limits the area of immediate danger to the public. Here we present size distribution for particulate matter collected during flights, near and far from the crater at various times. The particle data is then compared with simultaneously collected sulfur dioxide data and the rate of decay of is estimated. Sulfur and particle concentration variations with height in the far plume are presented. Some airborne measurements for H2S, NO, NO2 and CO2 will also be presented. This includes correlation matrices for simultaneous measurements of these gases and comparison to National Air Quality Standards and background values.}, subject = {Vulkanasche}, language = {en} } @inproceedings{RoegnvaldssonArnasonPalssonetal.2015, author = {R{\"o}gnvaldsson, {\´O}lafur and Arnason, Gylfi and Palsson, Thorgeir and Eliasson, Jonas and Weber, Konradin and B{\"o}hlke, Christoph and Thorsteinsson, Throstur and Tirpitz, Lukas and Platt, Ulrich and Smith, Paul D. and Jones, Roderic L.}, title = {Modeling of SO2 dispersion from the 2014 Holuhraun eruption in Iceland using WRF-Chem}, series = {Geophysical Research Abstracts: EGU General Assembly 2015}, volume = {17}, booktitle = {Geophysical Research Abstracts: EGU General Assembly 2015}, publisher = {Copernicus}, address = {G{\"o}ttingen}, year = {2015}, abstract = {The fissure eruption in Holuhraun in central Iceland is the country's largest lava and gas eruption since 1783 but has produced very little volcanic ash. The eruption started in late August 2014 and is still ongoing as of January 2015. The main threat from this event has been atmospheric pollution of SO2 that is carried by wind to all parts of the country and produces elevated concentrations of SO2 that have frequently violated National Air Quality Standards (NAQS) in many population centers. The Volcanic Ash Research (VAR) group in Iceland is focused on airborne measurement of ash contamination to support safe air travel, as well as various gas concentrations. In relation to the Holuhraun eruption the VAR group has organized an investigation campaign including 10 measurement flights and performed measurements of both the source emissions and the plume distribution. SO2 concentrations measured at the source showed clear potential for creating pollution events in the toxic range and contamination of surface waters. The data obtained in the measurement campaign was used for calibration of the WRF-chem model of the dispersion of SO2 and volcanic ash concentration. The model has both been run in operational forecast mode (since mid October) as well as in a dynamical downscaling mode, to estimate the dispersion and fallout of SO2 from the plume. The model results indicate that a large part of the sulphur was precipitated in the Icelandic highlands. The first melt waters during the spring thaw are likely to contain acid sulphur compounds that can be harmful for vegetation, with the highland vegetation being the most vulnerable. These results will be helpful to estimate the pollution load on farmlands and pastures of farmers.}, subject = {Vulkanismus}, language = {en} } @inproceedings{WeberFischerAmend2020, author = {Weber, Konradin and Fischer, Christian and Amend, Detlef}, title = {A new development of drop-sondes for the measurement of CO2-concentrations at extended volcanic areas}, series = {Physics of Volcanoes 2020}, booktitle = {Physics of Volcanoes 2020}, pages = {32}, year = {2020}, abstract = {One of the main compounds emitted by volcanoes or volcanic fields is CO2. This is not only emitted from localized craters, but can emerge as distributed and fugitive emissions on extended volcanic areas. In this situation it is of interest to explore the distribution and horizontal concentration profiles of the CO2-emissions. For this purpose new drop-sondes for sensor measurements of CO2 emissions are under development at the Duesseldorf University of Applied Sciences. These drop-sondes are designed to be dropped from aircraft or drones over volcanic areas in order to map the distributed CO2 concentrations over longer times in an unattended way. They are very lightweight and cheap, so that a large number of drop-sondes might be deployed even over remote areas or regions with difficult access. The data are transmitted with GSM broadcasting and can be visualized on a geographical map. The drop-sondes use an NDIR CO2 sensor as a base for the measurement unit. Additionally to CO2 the atmospheric pressure, temperature and humidity are measured. The sensor unit is mounted in a special shock absorbing housing, which is designed to absorb impacts from the touch down after dropping of the sensor and is able to resist even adverse weather conditions. First measurement results and more details of the design of the sensor unit will be presented in this contribution}, subject = {Sonde}, language = {en} } @inproceedings{OPUS4-5070, title = {SPIE Proceedings, Remote Sensing of Clouds and the Atmosphere XXIV}, volume = {11152}, editor = {Comer{\´o}n, Adolfo and Kassianov, Evgueni I. and Sch{\"a}fer, Klaus and Picard, Richard H. and Weber, Konradin and Singh, Upendra N.}, publisher = {SPIE}, isbn = {9781510630086}, issn = {1996-756X}, year = {2019}, subject = {Telemetrie}, language = {en} } @inproceedings{WeberKramerFischeretal.2019, author = {Weber, Konradin and Kramer, Tim and Fischer, Christian and Pohl, Tobias and B{\"o}hlke, Christoph}, title = {Application and Feld-Testing of Different Low Cost Sensors for Particulate Matter}, series = {European Aerosol Conference 2019, 25.-30. August 2019, Gothenburg, Sweden}, booktitle = {European Aerosol Conference 2019, 25.-30. August 2019, Gothenburg, Sweden}, year = {2019}, subject = {Messtechnik}, language = {en} } @book{NiemannReichStoehr2024, author = {Niemann, J{\"o}rg and Reich, Benedikt and St{\"o}hr, Carsten}, title = {Lean Six Sigma: Methods for Production Optimization}, publisher = {Springer Nature}, address = {Berlin, Heidelberg}, isbn = {9783662687437}, doi = {10.1007/978-3-662-68744-4}, year = {2024}, subject = {Lean Management}, language = {en} } @inproceedings{WachtKaluzaFleiger2023, author = {Wacht, Anika and Kaluza, Stefan and Fleiger, Philipp}, title = {Carbon Capture and Utilization in Cement Industry—Aspects of the Production of E-Fuels by Upcycling Carbon Dioxide}, series = {Smart, Sustainable Manufacturing in an Ever-Changing World: Proceedings of International Conference on Competitive Manufacturing (COMA '22)}, booktitle = {Smart, Sustainable Manufacturing in an Ever-Changing World: Proceedings of International Conference on Competitive Manufacturing (COMA '22)}, editor = {Leipzig, Konrad von and Sacks, Natasha and Mc Clelland, Michelle}, publisher = {Springer Nature}, address = {Cham}, isbn = {9783031156014}, issn = {2194-0525}, doi = {10.1007/978-3-031-15602-1_44}, pages = {603 -- 612}, year = {2023}, subject = {Carbon dioxide capture and utilization}, language = {en} } @inproceedings{BlaineFusseneckerNiemannetal.2023, author = {Blaine, Deborah and Fussenecker, Claudia and Niemann, J{\"o}rg and Wolff, Karin}, title = {Did the Covid-19 Pandemic Improve Engineering Education?—A South African-German Perspective}, series = {Smart, Sustainable Manufacturing in an Ever-Changing World: Proceedings of International Conference on Competitive Manufacturing (COMA '22)}, booktitle = {Smart, Sustainable Manufacturing in an Ever-Changing World: Proceedings of International Conference on Competitive Manufacturing (COMA '22)}, editor = {Leipzig, Konrad von and Sacks, Natasha and Mc Clelland, Michelle}, publisher = {Springer Nature}, address = {Cham}, isbn = {9783031156014}, issn = {2194-0525}, doi = {10.1007/978-3-031-15602-1_25}, pages = {333 -- 345}, year = {2023}, subject = {COVID-19-Pandemie}, language = {en} } @inproceedings{GrambergKrugerNiemann2023, author = {Gramberg, Till and Kruger, Karel and Niemann, J{\"o}rg}, title = {Augmented Reality for Operators in Smart Manufacturing Environments: A Case Study Implementation}, series = {Smart, Sustainable Manufacturing in an Ever-Changing World: Proceedings of International Conference on Competitive Manufacturing (COMA '22)}, booktitle = {Smart, Sustainable Manufacturing in an Ever-Changing World: Proceedings of International Conference on Competitive Manufacturing (COMA '22)}, editor = {Leipzig, Konrad von and Sacks, Natasha and Mc Clelland, Michelle}, publisher = {Springer Nature}, address = {Cham}, isbn = {9783031156014}, issn = {2194-0525}, doi = {10.1007/978-3-031-15602-1_30}, pages = {401 -- 413}, year = {2023}, subject = {Erweiterte Realit{\"a}t (Informatik)}, language = {en} } @article{BeyerGroteReinig2008, author = {Beyer, Marc-Andr{\´e} and Grote, Wolfgang and Reinig, Gunter}, title = {Adaptive exact linearization control of batch polymerization reactors using a Sigma-Point Kalman Filter}, series = {Journal of Process Control}, volume = {18}, journal = {Journal of Process Control}, number = {7-8}, publisher = {Elsevier}, doi = {10.1016/j.jprocont.2007.12.002}, pages = {663 -- 675}, year = {2008}, abstract = {The Chylla-Haase polymerization reactor is widely accepted as a benchmark process for the evaluation of control strategies for batch reactors. In this contribution a control concept based on Exact I/O-Linearization is proposed and compared to a conventional cascade control structure. In order to adapt the exact linearization control strategy to various polymerization products and batch conditions, an advanced probabilistic inference algorithm (Sigma-Point Kalman Filter) is applied and investigated. Sigma-Point Kalman Filters have the major improvement of simplified implementation compared to local linearization methods (i.e. Extended Kalman Filter) because no analytical Jacobians are required. Stochastic simulation studies are introduced and show the effectiveness, accuracy and benefit of the control concept. Within several scenarios a satisfying robustness against structural errors in the underlying model equations for the nonlinear control law and the inference algorithm is demonstrated. Furthermore it is pointed out, that with little effort in reassembling the plant design, control performance can be improved significantly.}, language = {en} } @article{GalbanMaderwaldEggebrechtetal.2005, author = {Galban, Craig and Maderwald, Stefan and Eggebrecht, Holger and Grote, Wolfgang and de Greiff, A. and Uffmann, K. and Ladd, M. E.}, title = {Monitoring the Effects of Chronic Obstructive Pulmonary Disease on Muscle Elasticity by MR Elastography}, series = {Proc. Intl. Soc. Mag. Reson. Med.}, volume = {13}, journal = {Proc. Intl. Soc. Mag. Reson. Med.}, pages = {2015}, year = {2005}, abstract = {Men afflicted with chronic obstructive pulmonary disease (COPD) show signs of muscle dysfunction, such as increased muscle fatigue and acidosis during exercise. We hypothesize that muscle elasticity of the lower extremities differs between patients with COPD and age-related controls. The shear modulus of the soleus muscle was measured non-invasively using MR elastography (MRE) at 0\%, 5\%, 10\%, 15\%, and 20\% of the subject's maximum applied force. The results from this study showed statistical differences between the patients and controls, even though there were no statistical differences in the maximum applied force.}, language = {en} } @article{GalbanMaderwaldHerrmannetal.2005, author = {Galban, Craig and Maderwald, Stefan and Herrmann, Burkhard and Brauck, K. and Grote, Wolfgang and de Greiff, A. and Uffmann, K. and Ladd, M.}, title = {Measuring Skeletal Muscle Elasticity in Patients with Hypogonadism by MR Elastography}, series = {Proc. Intl. Soc. Mag. Reson. Med.}, volume = {13}, journal = {Proc. Intl. Soc. Mag. Reson. Med.}, pages = {2016}, year = {2005}, abstract = {Men afflicted with hypogonadism have reduced fat-free mass and in some cases a loss in muscle strength. We hypothesize that muscle elasticity of the lower extremities differs between patients with hypogonadism and healthy controls. The shear modulus of the soleus muscle was measured non-invasively using MR elastography (MRE) at 0\%, 5\%, 10\%, 15\%, and 20\% of the subject's maximum applied force. The results from this study showed statistical differences between the patients and controls, even though there were no statistical differences in applied force.}, language = {en} } @article{MandalBiswasMannaetal.2024, author = {Mandal, Dipak Kumar and Biswas, Nirmalendu and Manna, Nirmal K and Benim, Ali Cemal}, title = {Impact of chimney divergence and sloped absorber on energy efficacy of a solar chimney power plant (SCPP)}, series = {Ain Shams Engineering Journal}, journal = {Ain Shams Engineering Journal}, publisher = {Elsevier}, issn = {2090-4495}, doi = {10.1016/j.asej.2023.102390}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-42410}, year = {2024}, abstract = {A numerical study is carried out meticulously to scrutinize the impact of different shapes of chimneys like circular (outer dia, dc), convergent (outer dia, 0.5dc), divergent (outer dia, 1.5dc), sudden contraction (outer dia, 0.5dc), and sudden expansion (outer dia, 1.5dc) on the performance of an SCPP. Furthermore, the parametric impact with different chimney divergence angles (CDA, ϕ), and ground absorber slope angle (GSA, γ) on the SCPP performance is also scrutinized. Optimum divergence angle (ϕ=+0.75◦) enhances the power generation up to ~ 47\% (76 kW) with a horizontal ground absorber surface. An increase or decrease in CDA lessens the power generation. With a sloped ground absorber angle γ=0.6◦, the gain in power generation is 60\% (82 kW). The study of combination of ground sloped absorber (γ=0.6◦) and divergent chimney (ϕ=+0.75◦) shows enhancement of the power generation upto 80\% (92 kW) more than the classical Manzaranes plant.}, language = {en} } @misc{LessmannMeuterMueller2018, author = {Lessmann, Stephanie and Meuter, Mirko and Mueller, Dennis}, title = {Method to determine distance of an object from an automated vehicle with a monocular device}, year = {2018}, abstract = {A method of determining the distance of an object from an automated vehicle based on images taken by a monocular image acquiring device. The object is recognized with an object-class by means of an image processing system. Respective position data are determined from the images using a pinhole camera model based on the object-class. Position data indicating in world coordinates the position of a reference point of the object with respect to the plane of the road is used with a scaling factor of the pinhole camera model estimated by means of a Bayes estimator using the position data as observations and under the assumption that the reference point of the object is located on the plane of the road with a predefined probability. The distance of the object from the automated vehicle is calculated from the estimated scaling factor using the pinhole camera model.}, language = {en} } @article{MolloyMuellerDeeganetal.2024, author = {Molloy, Dara and M{\"u}ller, Patrick and Deegan, Brian and Mullins, Darragh and Horgan, Jonathan and Ward, Enda and Jones, Edward and Braun, Alexander and Glavin, Martin}, title = {Analysis of the Impact of Lens Blur on Safety-Critical Automotive Object Detection}, series = {IEEE Access}, volume = {12}, journal = {IEEE Access}, publisher = {IEEE}, issn = {2169-3536}, doi = {10.1109/ACCESS.2023.3348663}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-42999}, pages = {3554 -- 3569}, year = {2024}, abstract = {Camera-based object detection is widely used in safety-critical applications such as advanced driver assistance systems (ADAS) and autonomous vehicle research. Road infrastructure has been designed for human vision, so computer vision, with RGB cameras, is a vital source of semantic information from the environment. Sensors, such as LIDAR and RADAR, are also often utilized for these applications; however, cameras provide a higher spatial resolution and color information. The spatial frequency response (SFR), or sharpness of a camera, utilized in object detection systems must be sufficient to allow a detection algorithm to localize objects in the environment over its lifetime reliably. This study explores the relationship between object detection performance and SFR. Six state-of-the-art object detection models are evaluated with varying levels of lens defocus. A novel raw image dataset is created and utilized, containing pedestrians and cars over a range of distances up to 100-m from the sensor. Object detection performance for each defocused dataset is analyzed over a range of distances to determine the minimum SFR necessary in each case. Results show that the relationship between object detection performance and lens blur is much more complex than previous studies have found due to lens field curvature, chromatic aberration, and astigmatisms. We have found that smaller objects are disproportionately impacted by lens blur, and different object detection models have differing levels of robustness to lens blur}, language = {en} } @inproceedings{LorenzenSchoenigGroteRammetal.2023, author = {Lorenzen, Finn and Sch{\"o}nig, Felix and Grote-Ramm, Wolfgang and Oliveira Brito, Marcel and Neuberger, Heiko and Sobolyev, Alexander}, title = {Continual Adaptation of Compressor Maps During Operation on Measurement Data For Increased Performance of Model-Based Applications in Turbomachinery}, series = {ASME Turbo Expo 2023: Turbomachinery Technical Conference and Exposition, June 26-30, 2023 Boston, Massachusetts, USA}, volume = {Volume 4}, booktitle = {ASME Turbo Expo 2023: Turbomachinery Technical Conference and Exposition, June 26-30, 2023 Boston, Massachusetts, USA}, publisher = {ASME}, address = {Boston}, isbn = {978-0-7918-8697-7}, doi = {10.1115/GT2023-103458}, pages = {1 -- 7}, year = {2023}, abstract = {Higher control engineering concepts, including artificial intelligence and model-based control, are recently becoming more popular in complex industrial applications because they enable a significant increase in efficiency. E.g., a model-based approach can be used to enhance the control and monitoring of several coupled components of a larger turbomachinery train. This requires dynamic models of the components, including all machine characteristics, which may experience a shift in their behavior over the course of their lifetime. Such changes occur due to natural fouling, wear of sub-components or external effects induced by maintenance measures. To overcome this problem, we model machine-characteristic maps with artificial neural networks, which may be used as part of prediction models in a model predictive control unit. If an appropriate data set is available, this allows us to adapt the model to the current behavior of the machine without requiring in-depth knowledge about the underlying physics of this "concept drift", as it is known in literature. However, the training of neural networks is usually connected with high computational effort while the task needs to be executed in real-time during operation. Furthermore, in real operating conditions, machine sensors can only provide labeled data from the current operating point of the machine, which can be stationary for long operation periods of up to several months. In general, this yields only an unrepresentative data subset of the machine-characteristics, which is not sufficient to retrain the whole model to a new state. To solve these problems, we firstly reduce the model adaptation to a convex optimization problem, which can be efficiently solved in real-time conditions. Secondly, we use a specialized data management system with which we can integrate historical data to supplement the unrepresentative data subset. In this paper we show the application of the outlined method on a compressor map and discuss the advantages and requirements of the method in the context of modeling applications for industrial turbomachinery.}, language = {en} } @inproceedings{GroteRammSchoenig2022, author = {Grote-Ramm, Wolfgang and Sch{\"o}nig, Felix}, title = {Model Predictive Control of Solar Receivers}, series = {25th Cologne Solar Colloquium (DLR)}, booktitle = {25th Cologne Solar Colloquium (DLR)}, publisher = {DLR Institut f{\"u}r Solarforschung}, pages = {17}, year = {2022}, language = {en} } @inproceedings{SchrammKrugerNiemannetal.2019, author = {Schramm, Alexander and Kruger, Karl and Niemann, J{\"o}rg and Grote, Wolfgang}, title = {Possibilities, Limitations and Considerations for Eye Tracking in Industrial Environments: Experience from a Case Study}, series = {International Conference on Competitive Manufacturing (COMA 19) proceedings : 30 January 2019-1 February 2019, Stellenbosch, South Africa}, booktitle = {International Conference on Competitive Manufacturing (COMA 19) proceedings : 30 January 2019-1 February 2019, Stellenbosch, South Africa}, editor = {Dimitrov, Dimiter and Hagedorn-Hansen, Devon and Leipzig, Karl von}, publisher = {Department of Industrial Engineering, Stellenbosch University}, address = {Stellenbosch}, isbn = {978-0-7972-1779-9}, pages = {390 -- 396}, year = {2019}, abstract = {Eye tracking is a measurement technique for determining the orientation and viewing direction of an individual's eyes. It allows for an evaluation of the individual's gaze and other related information.There is a wide variety of application areas for eye tracking, however the usage in engineeringindustry is still limited. This paper presents a case study for the use of eye tracking in a testingstation for electrical circuit breakers. The case study aims to evaluate the measurement and analysispossible with the Tobii wearable eye tracking system. From the case study, possibilities, limitationsand considerations for eye tracking in industrial settings are identified and discussed. The paperconcludes that while eye tracking can be used to effectively capture and visualize insightfulinformation, it faces major challenges related to subjectivity in analysis and labour intensiveness.}, language = {en} } @article{MierMoellenbruckJostetal.2015, author = {Mier, Dominik and M{\"o}llenbruck, Florian and Jost, Michael and Grote, Wolfgang and M{\"o}nnigmann, Martin}, title = {Model predictive control of the steam cycle in a solar power plant}, series = {IFAC-PapersOnLine}, volume = {48}, journal = {IFAC-PapersOnLine}, number = {8}, publisher = {Elsevier}, issn = {2405-8963}, doi = {10.1016/j.ifacol.2015.09.052}, pages = {710 -- 715}, year = {2015}, abstract = {We derive a nonlinear model of the steam cycle of a solar power plant, estimate its unknown parameters with measured data, and design a linear model predictive controller based on the resulting model. Simulations show that the linear model predictive controller is able to regulate the electrical power of the nonlinear steam process of the plant to a given reference trajectory very well. Moreover, it results in very good disturbance rejection.}, language = {en} } @article{JostGroteMoellenbrucketal.2014, author = {Jost, Michael and Grote, Wolfgang and M{\"o}llenbruck, Florian and M{\"o}nnigmann, Martin}, title = {Plant-wide control of a parabolic trough power plant with thermal energy storage}, series = {IFAC Proceedings Volumes}, volume = {47}, journal = {IFAC Proceedings Volumes}, number = {3}, publisher = {Elsevier}, issn = {2589-3653}, doi = {10.3182/20140824-6-ZA-1003.00879}, pages = {419 -- 425}, year = {2014}, abstract = {We present a control scheme for a parabolic trough power plant that is equipped with a molten salt thermal energy storage system. We show that the multivariable control problem for the solar field can be decoupled by controlling the three way valve that splits the heat transfer fluid between the storage system and the steam generator. The steam generation cycle is regulated with inlet pressure control. The subsystems of the plant are modeled based on first principles, where we focus on the steam generation cycle. A multi-group extraction turbine with pre- and reheater is considered, which is suitable for solar power plants. We demonstrate the benefits of the proposed control scheme with a day-to-day simulation.}, language = {en} } @article{GroteKastsianMoennigmann2013, author = {Grote, Wolfgang and Kastsian, Darya and M{\"o}nnigmann, Martin}, title = {Guaranteed stability in optimal power generation dispatching under uncertainty}, series = {IEEE Transactions on Power Systems}, volume = {28}, journal = {IEEE Transactions on Power Systems}, number = {2}, publisher = {IEEE}, issn = {1558-0679}, doi = {10.1109/TPWRS.2012.2207970}, pages = {1103 -- 1112}, year = {2013}, abstract = {Stability and cost optimality of power generation and supply systems must not be considered independently from one another. Simple examples show that optimizing cost without considering stability may result in modes of operation that, while economically optimal, are unstable. We demonstrate that stability, robustness, and optimality can be considered systematically and simultaneously by combining bifurcation theory and nonlinear optimization. Essentially, the proposed method enforces a backoff distance between the optimal point of operation and operational or stability boundaries in the space of the optimization variables, where bifurcation theory is used to describe nonlinear stability boundaries.}, language = {en} } @inproceedings{GroteKastsianMoennigmann2011, author = {Grote, Wolfgang and Kastsian, Darya and M{\"o}nnigmann, Martin}, title = {Optimal power system unit commitment with guaranteed local stability}, series = {Proceedings of the 2011 American Control Conference}, booktitle = {Proceedings of the 2011 American Control Conference}, publisher = {IEEE}, issn = {2378-5861}, doi = {10.1109/ACC.2011.5991058}, pages = {4526 -- 4531}, year = {2011}, abstract = {This article deals with the cost optimal commitment of power systems. System stability is often only considered after solving the commitment problem. We show by example that a cost optimization may result in a mode of operation that, while economically optimal, is unstable or has otherwise unacceptable dynamics. As a remedy, we propose to use the so-called normal vector method, which has been developed for the optimization of nonlinear dynamical systems with stability boundaries and uncertain parameters. We apply the method to a small sample power grid, where the optimization goal is to minimize the energy production costs for a given power consumption.}, language = {en} } @inproceedings{LangmannCoppenrath2019, author = {Langmann, Reinhard and Coppenrath, Matthias}, title = {A Cloud-Based Blended Learning Lab for PLC Education}, series = {Smart Industry \& Smart Education: Proceedings of the 15th International Conference on Remote Engineering and Virtual Instrumentation}, booktitle = {Smart Industry \& Smart Education: Proceedings of the 15th International Conference on Remote Engineering and Virtual Instrumentation}, editor = {Langmann, Rainhard and Auer, Michael E.}, publisher = {Springer Nature}, address = {Cham}, isbn = {9783319956770}, issn = {2367-3370}, doi = {10.1007/978-3-319-95678-7_1}, pages = {3 -- 13}, year = {2019}, subject = {Integriertes Lernen}, language = {en} } @article{KamiloğluSunBosetal.2024, author = {Kamiloğlu, Roza G. and Sun, Rui and Bos, Patrick and Huber, Florian and Attema, Jisk Jakob and Sauter, Disa A.}, title = {Tickling induces a unique type of spontaneous laughter}, series = {Biology Letters}, volume = {20}, journal = {Biology Letters}, number = {11}, publisher = {The Royal Society}, issn = {1744-957X}, doi = {10.1098/rsbl.2024.0543}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-47446}, year = {2024}, abstract = {Laughing is ubiquitous in human life, yet what causes it and how it sounds is highly variable. Considering this diversity, we sought to test whether there are fundamentally different kinds of laughter. Here, we sampled spontaneous laughs (n = 887) from a wide range of everyday situations (e.g. comedic performances and playful pranks). Machine learning analyses showed that laughs produced during tickling are acoustically distinct from laughs triggered by other kinds of events (verbal jokes, watching something funny or witnessing someone else's misfortune). In a listening experiment (n = 201), participants could accurately identify tickling-induced laughter, validating that such laughter is not only acoustically but also perceptually distinct. A second listening study (n = 210) combined with acoustic analyses indicates that tickling-induced laughter involves less vocal control than laughter produced in other contexts. Together, our results reveal a unique acoustic and perceptual profile of laughter induced by tickling, an evolutionarily ancient play behaviour, distinguishing it clearly from laughter caused by other triggers. This study showcases the power of machine learning in uncovering patterns within complex behavioural phenomena, providing a window into the evolutionary significance of ticking-induced laughter.}, subject = {Lachen}, language = {en} } @article{MildauEhlersMeisenburgetal.2024, author = {Mildau, Kevin and Ehlers, Henry and Meisenburg, Mara and Del Pup, Elena and Koetsier, Robert A. and Torres Ortega, Laura Rosina and de Jonge, Niek F. and Singh, Kumar Saurabh and Ferreira, Dora and Othibeng, Kgalaletso and Tugizimana, Fidele and Huber, Florian and van der Hooft, Justin J. J.}, title = {Effective data visualization strategies in untargeted metabolomics}, series = {Natural Product Reports}, journal = {Natural Product Reports}, publisher = {Royal Society of Chemistry}, issn = {0265-0568}, doi = {10.1039/d4np00039k}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-47596}, pages = {38}, year = {2024}, abstract = {LC-MS/MS-based untargeted metabolomics is a rapidly developing research field spawning increasing numbers of computational metabolomics tools assisting researchers with their complex data processing, analysis, and interpretation tasks. In this article, we review the entire untargeted metabolomics workflow from the perspective of information visualization, visual analytics and visual data integration. Data visualization is a crucial step at every stage of the metabolomics workflow, where it provides core components of data inspection, evaluation, and sharing capabilities. However, due to the large number of available data analysis tools and corresponding visualization components, it is hard for both users and developers to get an overview of what is already available and which tools are suitable for their analysis. In addition, there is little cross-pollination between the fields of data visualization and metabolomics, leaving visual tools to be designed in a secondary and mostly ad hoc fashion. With this review, we aim to bridge the gap between the fields of untargeted metabolomics and data visualization. First, we introduce data visualization to the untargeted metabolomics field as a topic worthy of its own dedicated research, and provide a primer on cutting-edge visualization research into data visualization for both researchers as well as developers active in metabolomics. We extend this primer with a discussion of best practices for data visualization as they have emerged from data visualization studies. Second, we provide a practical roadmap to the visual tool landscape and its use within the untargeted metabolomics field. Here, for several computational analysis stages within the untargeted metabolomics workflow, we provide an overview of commonly used visual strategies with practical examples. In this context, we will also outline promising areas for further research and development. We end the review with a set of recommendations for developers and users on how to make the best use of visualizations for more effective and transparent communication of results.}, subject = {Metabolomik}, language = {en} } @article{BenimZinser1985, author = {Benim, Ali Cemal and Zinser, Walter}, title = {Investigation into the finite element analysis of confined turbulent flows using a κ-ε model of turbulence}, series = {Computer Methods in Applied Mechanics and Engineering}, volume = {51}, journal = {Computer Methods in Applied Mechanics and Engineering}, number = {1-3}, publisher = {Elsevier}, issn = {0045-7825}, doi = {10.1016/0045-7825(85)90045-3}, pages = {507 -- 523}, year = {1985}, subject = {Finite-Elemente-Methode}, language = {en} } @article{BenimZinser1986, author = {Benim, Ali Cemal and Zinser, Walter}, title = {A segregated formulation of Navier-Stokes equations with finite elements}, series = {Computer Methods in Applied Mechanics and Engineering}, volume = {57}, journal = {Computer Methods in Applied Mechanics and Engineering}, number = {2}, publisher = {Elsevier}, issn = {0045-7825}, doi = {10.1016/0045-7825(86)90015-0}, pages = {223 -- 237}, year = {1986}, subject = {Navier-Stokes-Gleichung}, language = {en} } @article{Benim1988, author = {Benim, Ali Cemal}, title = {A finite element solution of radiative heat transfer in participating media utilizing the moment method}, series = {Computer Methods in Applied Mechanics and Engineering}, volume = {67}, journal = {Computer Methods in Applied Mechanics and Engineering}, number = {1}, publisher = {Elsevier}, issn = {0045-7825}, doi = {10.1016/0045-7825(88)90065-5}, pages = {1 -- 14}, year = {1988}, subject = {Finite-Elemente-Methode}, language = {en} } @article{Benim1989, author = {Benim, Ali Cemal}, title = {Finite element solution of an enclosed turbulent diffusion flame}, series = {International Journal for Numerical Methods in Fluids}, volume = {9}, journal = {International Journal for Numerical Methods in Fluids}, number = {3}, publisher = {Wiley}, issn = {0271-2091}, doi = {10.1002/fld.1650090305}, pages = {289 -- 303}, year = {1989}, abstract = {A finite element formulation of enclosed turbulent diffusion flames is presented. A primitive variables approach is preferred in the analysis. A mixed interpolation is employed for the velocity and pressure. In the solution of the Navier-Stokes equations, a segregated formulation is adopted, where the pressure discretization equation is obtained directly from the discretized continuity equation, considering the velocity-pressure relationships in the discretized momentum equations. The state of turbulence is defined by a κ-ϵ model. Near solid boundaries, a wall function approach is employed. The combustion rates are estimated using the eddy dissipation concept. The expensive direct treatment of the integrodifferential equations of radiation is avoided by employing the moment method, which allows the derivation of an approximate local field equation for the radiation intensity. The proposed finite element model is verified by investigating a technical turbulent diffusion flame of semi-industrial size, and comparing the results with experiments and finite difference predictions.}, subject = {Finite-Elemente-Methode}, language = {en} } @article{BenimZinserSchnell1989, author = {Benim, Ali Cemal and Zinser, Walter and Schnell, Uwe}, title = {Investigation into the finite element analysis of enclosed turbulent diffusion flames}, series = {Applied Mathematical Modelling}, volume = {13}, journal = {Applied Mathematical Modelling}, number = {5}, publisher = {Elsevier}, issn = {0307-904X}, doi = {10.1016/0307-904X(89)90069-3}, pages = {258 -- 267}, year = {1989}, subject = {Finite-Elemente-Methode}, language = {en} } @article{SuhBenim1989, author = {Suh, S.-H. and Benim, Ali Cemal}, title = {The primitive variables formulation of the Navier-Stokes equations using the finite analytic method}, series = {Applied Mathematical Modelling}, volume = {13}, journal = {Applied Mathematical Modelling}, number = {9}, publisher = {Elsevier}, issn = {0307-904X}, doi = {10.1016/0307-904X(89)90066-8}, pages = {550 -- 554}, year = {1989}, subject = {Navier-Stokes-Gleichung}, language = {en} } @article{Benim1990, author = {Benim, Ali Cemal}, title = {Finite element analysis of confined turbulent swirling flows}, series = {International Journal for Numerical Methods in Fluids}, volume = {11}, journal = {International Journal for Numerical Methods in Fluids}, number = {6}, publisher = {Wiley}, issn = {0271-2091}, doi = {10.1002/fld.1650110602}, pages = {697 -- 717}, year = {1990}, abstract = {The finite element method is applied to incompressible and statistically steady confined turbulent swirling flows. A velocity-pressure formulation is employed. The momentum and continuity equations are solved using a segregated algorithm. Two turbulence models, namely the standard κ-ε model and the algebraic stress model, are considered. It is shown that the algebraic stress model leads to significantly more accurate results in swirling flows compared to the κ-ε model. A novel way of implementing the algebraic stress model is presented in which the stresses are coupled to the Navier-Stokes equations in such a way that they 'correct' the effective viscosity hypothesis. This formulation seems to provide a convenient approach for finite elements. In deriving the discretization equations, a streamline-upwind/Petrov-Galerkin method is employed. Comparisons performed between various upwind schemes show that the numerical solution may be substantially affected by the particular upwind procedure used. The analysis is extended to the prediction of particle motion in turbulent swirling flow fields. Here the fluid turbulence is modelled adopting a stochastic approach. The influence of turbulence modelling on particle movement is investigated.}, subject = {Finite-Elemente-Methode}, language = {en} } @article{BenimNeuhoff1993, author = {Benim, Ali Cemal and Neuhoff, H. G.}, title = {Analysis of erosion behaviour in a turbocharger radial turbine}, series = {International Journal for Numerical Methods in Fluids}, volume = {16}, journal = {International Journal for Numerical Methods in Fluids}, number = {4}, publisher = {Wiley}, issn = {0271-2091}, doi = {10.1002/fld.1650160402}, pages = {259 -- 285}, year = {1993}, abstract = {An analysis of the erosion behaviour of a turbocharger radial turbine is presented. The solution domain includes both sides of the radial turbine scroll with double intake and the rotor channel. In the analysis a dilute gas-particle flow assumption is employed. The gas turbulence is defined by the k-ε model. In solving the gas phase equation, the computer code Harwell-FLOW3D is employed, which is based on a finite volume formulation using non-orthogonal body-fitted structured gridding and a pressure correction method. The particle phase is described by a Lagrangian approach, while particle paths are computed deterministically, neglecting the turbulent dispersion. For the computation of particle trajectories the code PTRACK is employed, which has been developed at ABB. Computations are carried out for several particle size classes. The results show that particles are thrown back into the scroll by the rotor at high rates. This seems to be the main source of erosion effects in the scroll. It has been observed that particles are unequally distributed between the scroll sides on their re-entry, resulting in greater erosion on one of the scroll sides. The maximum erosion along the scroll is found to be likely to occur near the scroll end.}, subject = {Erosion}, language = {en} } @article{XiaSmithBenimetal.1997, author = {Xia, Jiliang and Smith, Brian L. and Benim, Ali Cemal and Schmidli, Jiirg and Yadigaroglu, George}, title = {Effect of inlet and outlet boundary conditions on swirling flows}, series = {Computers \& Fluids}, volume = {26}, journal = {Computers \& Fluids}, number = {8}, publisher = {Elsevier}, issn = {0045-7930}, doi = {10.1016/S0045-7930(97)00026-1}, pages = {811 -- 823}, year = {1997}, subject = {Numerische Str{\"o}mungssimulation}, language = {en} } @article{BenimSyed1998, author = {Benim, Ali Cemal and Syed, Khawar J.}, title = {Laminar flamelet modelling of turbulent premixed combustion}, series = {Applied Mathematical Modelling}, volume = {22}, journal = {Applied Mathematical Modelling}, number = {1-2}, publisher = {Elsevier}, issn = {0307-904X}, doi = {10.1016/S0307-904X(98)00012-2}, pages = {113 -- 136}, year = {1998}, subject = {Verbrennung}, language = {en} } @article{BenimPasqualotto1998, author = {Benim, Ali Cemal and Pasqualotto, E.}, title = {Investigation into the computational modelling of diesel engine side injection systems}, series = {International Journal of Computer Applications in Technology}, volume = {11}, journal = {International Journal of Computer Applications in Technology}, number = {3-5}, publisher = {Inderscience}, issn = {0952-8091}, doi = {10.1504/IJCAT.1998.062199}, pages = {211 -- 218}, year = {1998}, subject = {Numerische Str{\"o}mungssimulation}, language = {en} } @article{PasqualottoBenim2001, author = {Pasqualotto, E. and Benim, Ali Cemal}, title = {A new phenomenological modelling approach for diesel engine side injection systems and comparison with computational fluid dynamics}, volume = {1}, number = {1-3}, publisher = {Inderscience}, issn = {1468-4349}, doi = {10.1504/PCFD.2001.001479}, pages = {149 -- 158}, year = {2001}, subject = {Numerische Str{\"o}mungssimulation}, language = {en} } @article{EppleBenim2003, author = {Epple, B. and Benim, Ali Cemal}, title = {A CRFD study of supercritical 2 x 900 MW boilers for Shanghai, P.R. of China}, series = {Progress in Computational Fluid Dynamics}, volume = {3}, journal = {Progress in Computational Fluid Dynamics}, number = {2-4}, publisher = {Inderscience}, issn = {1468-4349}, doi = {10.1504/PCFD.2003.003772}, pages = {140 -- 144}, year = {2003}, subject = {Numerische Str{\"o}mungssimulation}, language = {en} } @article{CurcicVanWaeyenbergeVansteenkisteetal.2008, author = {Curcic, Michael and Van Waeyenberge, Bartel and Vansteenkiste, Arne and Weigand, Markus and Sackmann, Vitalij and Stoll, Hermann and F{\"a}hnle, Manfred and Tyliszczak, Tolek and Woltersdorf, Georg and Back, Christian H. and Sch{\"u}tz, Gisela}, title = {Polarization Selective Magnetic Vortex Dynamics and Core Reversal in Rotating Magnetic Fields}, series = {Physical Review Letters}, volume = {101}, journal = {Physical Review Letters}, number = {19}, publisher = {American Physical Society}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.101.197204}, year = {2008}, language = {en} } @article{VansteenkisteDeBaerdemaekerChouetal.2008, author = {Vansteenkiste, A. and De Baerdemaeker, J. and Chou, Kang Wei and Stoll, H. and Curcic, Michael and Tyliszczak, T. and Woltersdorf, G. and Back, Christian H. and Sch{\"u}tz, G. and Van Waeyenberge, B.}, title = {Influence of domain wall pinning on the dynamic behavior of magnetic vortex structures: Time-resolved scanning x-ray transmission microscopy in NiFe thin film structures}, series = {Physical Review B}, volume = {77}, journal = {Physical Review B}, number = {14}, publisher = {American Physical Society}, issn = {1098-0121}, doi = {10.1103/PhysRevB.77.144420}, year = {2008}, language = {en} } @article{WeigandVanWaeyenbergeVansteenkisteetal.2009, author = {Weigand, Markus and Van Waeyenberge, Bartel and Vansteenkiste, Arne and Curcic, Michael and Sackmann, Vitalij and Stoll, Hermann and Tyliszczak, Tolek and Kaznatcheev, Konstantine and Bertwistle, Drew and Woltersdorf, Georg and Back, Christian H. and Sch{\"u}tz, Gisela}, title = {Vortex Core Switching by Coherent Excitation with Single In-Plane Magnetic Field Pulses}, series = {Physical Review Letters}, volume = {102}, journal = {Physical Review Letters}, number = {7}, publisher = {American Physical Society}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.102.077201}, year = {2009}, language = {en} } @article{VansteenkisteWeigandCurcicetal.2009, author = {Vansteenkiste, A and Weigand, M and Curcic, Michael and Stoll, H and Sch{\"u}tz, G and Van Waeyenberge, B}, title = {Chiral symmetry breaking of magnetic vortices by sample roughness}, series = {New Journal of Physics}, volume = {11}, journal = {New Journal of Physics}, number = {6}, publisher = {IOP Publishing}, issn = {1367-2630}, doi = {10.1088/1367-2630/11/6/063006}, year = {2009}, language = {en} } @article{VansteenkisteChouWeigandetal.2009, author = {Vansteenkiste, A. and Chou, Kang Wei and Weigand, M. and Curcic, Michael and Sackmann, V. and Stoll, H. and Tyliszczak, T. and Woltersdorf, G. and Back, Christian H. and Sch{\"u}tz, G. and Van Waeyenberge, B.}, title = {X-ray imaging of the dynamic magnetic vortex core deformation}, series = {Nature Physics}, volume = {5}, journal = {Nature Physics}, number = {5}, publisher = {Nature Publishing Group}, issn = {1745-2473}, doi = {10.1038/nphys1231}, pages = {332 -- 334}, year = {2009}, language = {en} } @article{KamionkaMartensChouetal.2010, author = {Kamionka, Thomas and Martens, Michael and Chou, Kang Wei and Curcic, Michael and Drews, Andr{\´e} and Sch{\"u}tz, Gisela and Tyliszczak, Tolek and Stoll, Hermann and Van Waeyenberge, Bartel and Meier, Guido}, title = {Magnetic Antivortex-Core Reversal by Circular-Rotational Spin Currents}, series = {Physical Review Letters}, volume = {105}, journal = {Physical Review Letters}, number = {13}, publisher = {American Physical Society}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.105.137204}, year = {2010}, language = {en} } @article{BisigRhensiusKammereretal.2010, author = {Bisig, Andre and Rhensius, Jan and Kammerer, Matthias and Curcic, Michael and Stoll, Hermann and Sch{\"u}tz, Gisela and Van Waeyenberge, Bartel and Chou, Kang Wei and Tyliszczak, Tolek and Heyderman, Laura J. and Krzyk, Stephen and von Bieren, Arndt and Kl{\"a}ui, Mathias}, title = {Direct imaging of current induced magnetic vortex gyration in an asymmetric potential well}, series = {Applied Physics Letters}, volume = {96}, journal = {Applied Physics Letters}, number = {15}, publisher = {AIP Publishing}, issn = {0003-6951}, doi = {10.1063/1.3373590}, year = {2010}, abstract = {Employing time-resolved x-ray microscopy, we investigate the dynamics of a pinned magnetic vortex domain wall in a magnetic nanowire. The gyrotropic motion of the vortex core is imaged in response to an exciting ac current. The elliptical vortex core trajectory at resonance reveals asymmetries in the local potential well that are correlated with the pinning geometry. Using the analytical model of a two-dimensional harmonic oscillator, we determine the resonance frequency of the vortex core gyration and, from the eccentricity of the vortex core trajectory at resonance, we can deduce the stiffness of the local potential well.}, language = {en} } @article{KammererWeigandCurcicetal.2011, author = {Kammerer, Matthias and Weigand, Markus and Curcic, Michael and Noske, Matthias and Sproll, Markus and Vansteenkiste, Arne and Van Waeyenberge, Bartel and Stoll, Hermann and Woltersdorf, Georg and Back, Christian H. and Schuetz, Gisela}, title = {Magnetic vortex core reversal by excitation of spin waves}, series = {Nature Communications}, volume = {2}, journal = {Nature Communications}, number = {1}, publisher = {Springer Nature}, issn = {2041-1723}, doi = {10.1038/ncomms1277}, year = {2011}, language = {en} } @article{CurcicStollWeigandetal.2011, author = {Curcic, Michael and Stoll, Hermann and Weigand, Markus and Sackmann, Vitalij and Juellig, Patrick and Kammerer, Matthias and Noske, Matthias and Sproll, Markus and Van Waeyenberge, Bartel and Vansteenkiste, Arne and Woltersdorf, Georg and Tyliszczak, Tolek and Sch{\"u}tz, Gisela}, title = {Magnetic vortex core reversal by rotating magnetic fields generated on micrometer length scales}, series = {physica status solidi (b)}, volume = {248}, journal = {physica status solidi (b)}, number = {10}, publisher = {Wiley}, issn = {0370-1972}, doi = {10.1002/pssb.201147208}, pages = {2317 -- 2322}, year = {2011}, abstract = {AbstractUnidirectional switching of the magnetic vortex core can be achieved in micron-sized ferromagnetic platelets by excitation of the gyrotropic mode of the vortex structure with in-plane rotating magnetic fields. Circulating fields with a switchable sense of rotation (clockwise, CW or counter clockwise, CCW) have been generated on a micrometer length scale at frequencies up to 1 GHz by two orthogonal electric RF currents with 90° phase shift flowing through crossed but not isolated striplines. Decoupling of these currents is realized by balanced symmetric RF sources. The amplitudes of the rotating magnetic fields and their spatial distributions are calculated and the stripline geometry is discussed. By taking advantage of this technique, unidirectional vortex core reversal by excitation with CW or CCW rotating magnetic fields has been observed by time resolved scanning transmission X-ray microscopy. An area with reversed magnetization, the "dip," was observed near the vortex core before vortex core reversal.}, language = {en} } @inproceedings{WillersCurcicBosch2017, author = {Willers, Oliver and Curcic, Michael and Bosch, Robert}, title = {Fingerprinting MEMS Gyroscopes}, series = {11th Smart Systems Integration Conference 2017 International Conference and Exhibition on Integration Issues of Miniaturized Systems Cork, Ireland 8-9 March 2017}, booktitle = {11th Smart Systems Integration Conference 2017 International Conference and Exhibition on Integration Issues of Miniaturized Systems Cork, Ireland 8-9 March 2017}, editor = {Thomas, Otto}, publisher = {Curran Associates, Inc.}, isbn = {978-1-5108-4478-0}, pages = {133}, year = {2017}, language = {en} } @inproceedings{NabholzCurcicMehneretal.2019, author = {Nabholz, Ulrike and Curcic, Michael and Mehner, Jan E. and Degenfeld-Schonburg, Peter}, title = {Nonlinear Dynamical System Model for Drive Mode Amplitude Instabilities in MEMS Gyroscopes}, series = {2019 IEEE International Symposium on Inertial Sensors and Systems (INERTIAL), Naples, 01-05 April 2019}, booktitle = {2019 IEEE International Symposium on Inertial Sensors and Systems (INERTIAL), Naples, 01-05 April 2019}, publisher = {IEEE}, isbn = {978-1-5386-7828-2}, doi = {10.1109/ISISS.2019.8739703}, year = {2019}, language = {en} } @inproceedings{HonsbrokMostafawyHerderetal.2025, author = {Honsbrok, Jan and Mostafawy, Sina and Herder, Jens and Huldtgren, Alina}, title = {Ray-LUT: A Lookup-Based Method for Camera Lens Simulation in Real-Time Using Ray Tracing}, series = {Proceedings of the 20th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications}, booktitle = {Proceedings of the 20th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications}, publisher = {SciTePress}, doi = {10.5220/0013105900003912}, pages = {177 -- 184}, year = {2025}, abstract = {Lens systems have a major influence on the image due to effects such as depth of field or optical aberrations. The only method to simulate these effects precisely is to trace rays through an actual lens system. This provides accurate results, but only with high computational effort. To speed up the ray tracing through the lens system, various acceleration methods have been developed, requiring considerable precomputations. We present a new method based on the Realistic Camera by Kolb et. al.. Instead of tracing each ray through the lens system, the rays are precomputed once and stored in a lookup table. In contrast to other methods, our method is simple, and does not require substantial preprocessing upfront. We can simulate complex effects such as chromatic aberrations accurately in real-time, regardless the number of lens surfaces in the system. Our method achieves the same performance as state-of-the-art methods like Polynomial Optics, while maintaining the same number of samples per pixel.}, language = {en} } @inproceedings{DeckertMohya2022, author = {Deckert, Carsten and Mohya, Ahmed}, title = {Self-directed versus guided learning - searching for the sweet spot with lesson activities in Moodle}, series = {SEFI 50th Annual conference of The European Society for Engineering Education. "Towards a new future in engineering education, new scenarios that european alliances of tech universities open up."}, booktitle = {SEFI 50th Annual conference of The European Society for Engineering Education. "Towards a new future in engineering education, new scenarios that european alliances of tech universities open up."}, publisher = {Universitat Polit{\`e}cnica de Catalunya}, address = {Barcelona}, isbn = {978-84-123222-6-2}, doi = {10.5821/conference-9788412322262.1132}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-51759}, pages = {234 -- 242}, year = {2022}, abstract = {In times of a pandemic many university courses have to be taught in an online learning format to respect the requirements of social distancing. Online learning takes place between the poles of self-direction by the student and guidance by the lecturer. In this paper a first-semester course in industrial economics for engineers, which was taught in the self-directed learning format of flipped classroom, was enhanced with lesson activities in the Learning Management System (LMS) Moodle as a means of guided learning with student-content interaction. The paper describes the design and the evaluation of the lesson activities. For the evaluation a student survey to gather the opinions and self-assessments of the students was conducted, and statistical data from Moodle on the performance of the students were collected. The results of the student survey show an overall positive evaluation of the lesson activities by the students who participated in the lesson activities. Furthermore, the results of the statistical data about the students' performance show a relation between participation in the lesson activities and exam success. As a caveat, however, the results also show that the majority of the students chose not to participate in the lesson activities.}, subject = {Selbstgesteuertes Lernen}, language = {en} } @book{OPUS4-5154, title = {Doppelvilla am Juras{\"u}dfuß}, volume = {Band 3}, publisher = {Braun Publishing}, address = {Berlin}, organization = {Architektenkammer Berlin}, isbn = {978-3-03768-152-7}, pages = {30 -- 31}, year = {2014}, language = {en} } @inproceedings{WeberReichardtFischeretal.2012, author = {Weber, Konradin and Reichardt, R. and Fischer, Christian and Moser, H. M. and Eliasson, Jonas}, title = {Computational Visualization of Volcanic Ash Plume Concentrations Measured by light Aircrafts over Germany and Iceland during the Recent Eruptions of the Volcanoes Eyjafjallaj{\"o}kull and Grimsv{\"o}tn}, series = {Recent advances in Fluid Mechanics, Heat \& Mass Transfer, Biology and Ecology}, booktitle = {Recent advances in Fluid Mechanics, Heat \& Mass Transfer, Biology and Ecology}, editor = {Jha, Manoj K. and Lazard, Myriam and Zaharim, Azami and Sopian, Kamaruzzaman}, publisher = {WSEAS}, isbn = {978-1-61804-065-7}, pages = {236 -- 240}, year = {2012}, subject = {Vulkanasche}, language = {en} } @inproceedings{VogelWeberFischeretal.2011, author = {Vogel, Andreas and Weber, Konradin and Fischer, Christian and van Haren, G{\"u}nther and Pohl, Tobias and Grobety, Bernhard and Meier, Mario}, title = {Airborne in-situ measurements of the Eyjafjalloj{\"o}kull ash plume with a small aircraft and optical particle spectrometers over north-western Germany - comparison between the aircraft measurements and the VAAC-model calculations}, series = {Geophysical Research Abstracts: EGU General Assembly 2011}, volume = {13}, booktitle = {Geophysical Research Abstracts: EGU General Assembly 2011}, publisher = {Copernicus}, address = {G{\"o}ttingen}, year = {2011}, abstract = {The eruption of the volcano Eyjafjallaj{\"o}kull (Iceland) in 2010 has caused a transportation of an ash dust plume over large areas of Europe. In April 2010 many airports in Europe were closed for several days because of the volcano ash plume and even in May 2010 several German and European airports were closed for shorter periods because of the danger caused by the volcanic ash dust. The VAAC (Volcanic Ash Advisory Center), London, has continuously published graphics of the predicted spread and dispersion of the volcanic ash plume, which were partly basis for the air traffic restrictions in Germany. In this situation the Laboratory for Environmental Measurement Techniques of the University of Applied Sciences in Duesseldorf has performed 14 measurement flights starting from April 23 2010 to May 21 2010 to get real airborne in-situ dust measurement data over the north-western part of Germany and for comparison with the predicted ash dispersion model data of the VAAC of London in Germany. Moreover, airborne passive DOAS remote sensing measurements have been performed by a mini-DOAS system for SO2-measurements within the plume. In this paper the results of the airborne optical ash particle measurements as well as the remote sensing SO2 measurements will be reported for situations with and without the volcanic plume over northern Germany in detail. Moreover, the measured dust data will be compared with the model dispersion predictions for the ash plume by the VAAC and with European limit concentrations. Main conclusions are: The „ash plume", found by the aircraft measurement of the Duesseldorf University of Applied Sciences over north western Germany in the "red zone" predicted by the VAAC turned out to be inhomogeneous during the measurement flights Clusters of ash plume sometimes had only a height extension of several hundred meters or less Ash substructures with a horizontal extension of ten kilometres up to several tenth of kilometres could be found Vertical double structures of ash plume could be measured by spiral flights and could be observed visually in horizontal direction Ash plume could be observed visually as small brown layer in horizontal direction Particles collected during flight could be identified as ash particles by electron microscope analysis and chemical analysis}, subject = {Vulkanasche}, language = {en} } @inproceedings{KleinvonBergBirweetal.2024, author = {Klein, Paula and von Berg, Markus and Birwe, Dagmar and Steffens, Jochen}, title = {Can the Perceived Spatial Impression of Classical Recordings Be Predicted by Audio Descriptors? [Vortrag]}, series = {Fortschritte der Akustik - DAGA 2024}, booktitle = {Fortschritte der Akustik - DAGA 2024}, publisher = {Deutsche Gesellschaft f{\"u}r Akustik e.V.}, address = {Berlin}, isbn = {978-3-939296-22-5}, pages = {1034 -- 1037}, year = {2024}, abstract = {The perceived spatial impression is an important factor in the aesthetic appreciation of classical music recordings. Crucial aspects of spatial perception can be described by the attributes ensemble width, depth, envelopment, and reverberation duration. In a listening experiment, a sample of 30 experts rated 24 orchestra recordings by these attributes. To compare these ratings to signalrelated measures of spatial impression, an audio descriptor for the interaural cross-correlation coefficient in music recordings was chosen as a measure of perceived ensemble width. A second algorithm estimated the reverberation time from decay segments in the recorded music. Linear mixed-effects models were then used to test whether these two descriptors, combined with other audio features related to timbre, are suitable for predicting participants' ratings of the perceptual attributes. Overall, results confirmed that the signal-related measures used can indeed predict perceptual attributes, with 41\% of rating variance explained in the case of reverberation duration. In contrast, these objective measures turned out to be less accurate predictors of the perceived ensemble width, with a variance explanation of 21\%. This study can thus be regarded as a starting point for further studies aiming to predict the perceived spatial impression in music recordings.}, subject = {Raumakustik}, language = {en} } @inproceedings{Krieter2019, author = {Krieter, Philipp}, title = {Can I record your screen? mobile screen recordings as a long-term data source for user studies}, series = {Proceedings of the 18th International Conference on Mobile and Ubiquitous Multimedia, MUM2019, November 26-29, 2019, Pisa, Italy}, booktitle = {Proceedings of the 18th International Conference on Mobile and Ubiquitous Multimedia, MUM2019, November 26-29, 2019, Pisa, Italy}, editor = {Patern{\`o},, Fabio}, publisher = {ACM}, address = {New York}, isbn = {978-1-4503-7624-2}, doi = {10.1145/3365610.3365618}, pages = {1 -- 10}, year = {2019}, language = {en} } @article{Krieter2022, author = {Krieter, Philipp}, title = {Are You Still There? An Exploratory Case Study on Estimating Students' LMS Online Time by Combining Log Files and Screen Recordings}, series = {IEEE Transactions on Learning Technologies}, volume = {15}, journal = {IEEE Transactions on Learning Technologies}, number = {1}, publisher = {IEEE}, issn = {1939-1382}, doi = {10.1109/TLT.2022.3154828}, pages = {55 -- 63}, year = {2022}, abstract = {The time students spend in a learning management system (LMS) is an important measurement in learning analytics (LA). One of the most common data sources is log files from LMS, which do not directly reveal the online time, the duration of which needs to be estimated. As this measurement has a great impact on the results of statistical models in LA, its estimation is crucial. In the literature, there are many strategies for estimating the duration, which do not represent the actual online time of the students. In this article, we combine LMS log files of our students with parallel screen recordings and automatically analyze for how long the LMS is present in the video. We visualize the results and show that common online time estimation strategies do not represent the online time for our students accurately. By using modified online time estimation methods, we find estimations that fit the data of our students better on an individual basis.}, language = {en} } @inproceedings{KrieterViertelBreiter2020, author = {Krieter, Philipp and Viertel, Michael and Breiter, Andreas}, title = {We Know What You Did Last Semester: Learners' Perspectives on Screen Recordings as a Long-Term Data Source for Learning Analytics}, series = {Addressing global challenges and quality education: 15th European Conference on Technology Enhanced Learning, EC-TEL 2020, Heidelberg, Germany, September 14-18, 2020}, volume = {Lecture Notes in Computer Science, vol. 12315}, booktitle = {Addressing global challenges and quality education: 15th European Conference on Technology Enhanced Learning, EC-TEL 2020, Heidelberg, Germany, September 14-18, 2020}, editor = {Alario-Hoyos, Carlos and Rodr{\´i}guez-Triana, Mar{\´i}a Jes{\´u}s and Scheffel, Maren and Arnedillo-S{\´a}nchez, Inmaculada and Dennerlein, Sebastian Maximilian}, publisher = {Springer Nature}, address = {Cham}, isbn = {9783030577162}, issn = {0302-9743}, doi = {10.1007/978-3-030-57717-9_14}, pages = {187 -- 199}, year = {2020}, language = {en} } @phdthesis{Krieter2020, author = {Krieter, Philipp}, title = {Looking Inside - Mobile Screen Recordings as a Privacy Friendly Long-Term Data Source to Analyze User Behavior}, publisher = {Bremen}, address = {Universit{\"a}t Bremen}, doi = {10.26092/elib/103}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:46-elib43189}, year = {2020}, abstract = {Mobile devices are ubiquitous in many societies and shape the way we interact with technology and each other. Research on how we use and perceive technology is essential to understand its impact. This work advances how we can follow user behavior on mobile devices. We combine the strength of two common data sources for tracking on mobile devices, log files, and screen recordings. Log files are suitable for long-term and privacy-friendly analyzation but provide rather general data (e.g. system log files) unless one has access to the source code of the applications or operating systems. Screen recordings are usually used for short-termed analysis (e.g. usability tests) because the analysis is time-consuming, but they provide all activities on the screen in high detail regardless of which application or operating system. This thesis combines both data sources and presents an approach to automatically generate log files from mobile screen recordings. The approach utilizes methods of computer vision and machine learning to automatically process screen recordings and extend their use. Screen recordings reveal virtually everything a user does with a device, making privacy important, especially in user studies. We present a privacy concept and implementation and show how the risk of exposing private data can be reduced, by processing all recordings locally on the mobile devices and anonymizing the resulting log files. In order to apply the developed method in practice, we carry out a study in the context of education and show how log files of screen recordings can complement and extend existing research in learning analytics. This thesis opens up novel perspectives on how we can look at human-computer interaction with mobile devices. We show how to generate long-term log data with high detail and accuracy from mobile screen recordings, in a privacy-friendly way, locally on mobile devices.}, language = {en} } @inproceedings{KrieterBreiter2018, author = {Krieter, Philipp and Breiter, Andreas}, title = {Track every move of your students: log files for Learning Analytics from mobile screen recordings}, series = {DeLFI 2018: die 16. E-Learning Fachtagung Informatik der Gesellschaft f{\"u}r Informatik e.V., 10.-12. September 2018, Frankfurt am Main, Deutschland}, volume = {Lecture Notes in Informatics(LNI)-Proceedings, Vol. P-284}, booktitle = {DeLFI 2018: die 16. E-Learning Fachtagung Informatik der Gesellschaft f{\"u}r Informatik e.V., 10.-12. September 2018, Frankfurt am Main, Deutschland}, editor = {Kr{\"o}mker, Detlef and Schroeder, Ulrik}, publisher = {K{\"o}llen Druck+Verlag}, address = {Bonn}, organization = {Gesellschaft f{\"u}r Informatik, Bonn}, isbn = {9783885796787}, doi = {10.18154/RWTH-2018-229913}, pages = {231 -- 242}, year = {2018}, abstract = {One of the main data sources for Learning Analytics are Learning Management Systems (LMS).These log files are limited though to interactions within the LMS and cannot take into account interactions of students in other applications and software in a digital learning environment. In this paper, we present an approach for generating log files based on mobile screen recordings as a data source for Learning Analytics. Logging mobile application usage is limited to rather general system events unless you have access to the source code of the operating system or applications.To address this we generate log files from mobile screen recordings by applying computer vision and machine learning methods to detect individually defined events. In closing, we discuss how these log files can be used as a data source for Learning Analytics and relevant ethical concerns.}, language = {en} } @article{Gerhards2025, author = {Gerhards, Claudia}, title = {Social Media Influencers as "Dirty Workers": An Explorative Study on How They Use Strategies to Reduce the Moral Taint}, series = {Social Media + Society}, volume = {11}, journal = {Social Media + Society}, number = {2}, publisher = {SAGE Publications}, issn = {2056-3051}, doi = {10.1177/20563051251348917}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-54189}, pages = {17}, year = {2025}, abstract = {Since social media influencers have become popular and monetize their content with the help of advertising deals, they have been associated with morally questionable, deceptive behavior. The list of misconduct is long. It includes, for example, not disclosing sponsored content, withholding negative experiences with promoted products, buying fake followers, and promoting false ideals of beauty. Building on the concept of "dirty work" as a theoretical framework, this article asks which strategies influencers use to soften this moral taint. Qualitative interviews with influencers living in Germany show that they are aware of their negative image in public and use various stigma management strategies. This article offers a perspective that has not yet played a role in the ethics debate about influencers. It asks how influencers, who are often associated with morally questionable practices, immunize themselves against this negative image and find a positive work identity.}, language = {en} } @article{PohlHewelingFischeretal.2017, author = {Pohl, T. and Heweling, G. and Fischer, C. and Weber, Konradin}, title = {Traffic Influenced Nitrogen Dioxide, Ultrafine Particle and Black Carbon Concentrations at a Busy Urban Street in Duesseldorf, Germany}, series = {International Journal of Environmental Science}, volume = {2}, journal = {International Journal of Environmental Science}, issn = {2367-8941}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-50355}, pages = {410 -- 417}, year = {2017}, abstract = {In this study the road traffic related air pollution within a busy urban street canyon in the City of Duesseldorf, Germany was investigated. For the investigations the measurement truck of the laboratory for environmental measurement techniques of the HSD was equipped with different measurement devices for gaseous and aerosol species as well as meteorological sensors. The measurement truck was placed next to a stationary air quality measurement container of the Environmental State Agency of North-Rhine-Westphalia (LANUV). The measurement site is located at the Cornelius street, a direct north south connecting street through the city of Duesseldorf, which is highly frequented by road traffic with an daily amount of about 45,000 vehicles. The street is located within the low emission zone (LEZ). Additionally the pass through of vehicles with a higher weight than 7.5 tons is prohibited. Within this study over a period of several weeks the particle mass concentrations PM10, PM2.5 and PM1, and the particle number size distribution (PNSD) were measured over a broad range from 5 nm to 32 µm with a high temporal resolution. Additionally, an aethalometer was used to determine the proportion of black carbon in the particle ensembles. Gaseous pollutants like nitrogen dioxide, ozone and sulphur dioxide were measured as well. Nitrogen dioxide is a typical species originating from combustion processes. In this study the data from NO2 strongly correlate with ultrafine particle and black carbon concentrations and for this reason all three species are clearly influenced by road traffic. However, this effect is not so pronounced for the particle mass concentrations, which are additionally influenced by the varying local background concentrations. During the measurements, the averaged concentration for PM10 was on a moderate level at 20.6 µg/m³ (PM2.5 13.4 µg/m³, PM1 10.7 µg/m³). The averaged NO2 concentration was 54.2 µg/m³ during the measurement period, which is above the yearly limit value of 40 µg/m³. However, the hourly limit value of 200 µg/m³ was not exceeded during the measurement period of this study. The averaged particle number concentration (PNC5-250 nm) and black carbon concentration were on a low level compared with values from other studies at roadsides. The PNC5-250 nm was at 6,400 \#/cm³ and for black carbon at 1.8 µg/m³. The lower values for PNC and BC are possibly explained as a result due to the measures from the clean air plan. The measurements of this study took place in summertime. The air pollution concentrations might be higher during colder times of the year due to domestic fuel burning. After all it can be stated, that the additional monitoring of ultrafine particles and black carbon is relevant and important to characterize the composition of the air quality at roadsides and offer a better understanding for the temporal resolution of air pollutants in cities. Moreover, estimations on the risk of air pollution for the human health can more precisely be specified.}, language = {en} } @article{WeberHewelingFischeretal.2017, author = {Weber, Konradin and Heweling, Georg and Fischer, Christian and Lange, Martin}, title = {The use of an octocopter UAV for the determination of air pollutants - a case study of the traffic induced pollution plume around a river bridge in Duesseldorf, Germany}, series = {International Journal of Environmental Science}, volume = {2}, journal = {International Journal of Environmental Science}, issn = {2367-8941}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-50805}, pages = {63 -- 66}, year = {2017}, abstract = {Emissions of air pollutants from the road traffic are still a major problem in Germany. It is well known that traffic induced fine particulate matter (PM10, PM2.5, PM1), ultrafine particles (UFPs) and gaseous air pollutants, like e.g. NOx, are adverse to human health. Therefore it is important to monitor these air pollutants in the cities. In this study an octocopter UAV is used as a carrier for measurement systems for UFPs, fine particulate matter and soot. This instrumented octocopter was used for studying the vertical and horizontal variation of the air pollution plume, which originated from the traffic on a river bridge, connecting two parts of Duesseldorf in Germany. This octocopter UAV had been especially designed and built at the Duesseldorf University of Applied Sciences for measurements of air pollutants. It was featuring eight 900 W electric propeller drives and was equipped with a pixhawk flight control. Its lift off weight was about 10.5 kg. About 60 measurement flights were performed by the instrumented octocopter throughout this study. These measurement flights could clearly determine the traffic induced air pollution plume originating from the bridge. Moreover, the dispersion of UFPs within the pollution plume could be monitored with the octocopter flights.}, subject = {Flugk{\"o}rper}, language = {en} } @article{MuenchPriesmannReichetal.2024, author = {M{\"u}nch, Justin and Priesmann, Jan and Reich, Marius and Tillmanns, Marius and Praktiknjo, Aaron and Adam, Mario}, title = {Uplifting the Complexity of Analysis for Probabilistic Security of Electricity Supply Assessments using Artificial Neural Networks}, series = {Energy and AI}, journal = {Energy and AI}, publisher = {Elsevier}, issn = {2666-5468}, doi = {10.1016/j.egyai.2024.100401}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:due62-opus-45359}, year = {2024}, abstract = {The energy sector faces rapid decarbonisation and decision-makers demand reliable assessments of the security of electricity supply. For this, detailed simulation models with a high temporal and technological resolution are required. When confronted with increasing weather-dependent renewable energy generation, probabilistic simulation models have proven. The significant computational costs of calculating a scenario, however, limit the complexity of further analysis. Advances in code optimization as well as the use of computing clusters still lead to runtimes of up to eight hours per scenario. However ongoing research highlights that tailor-made approximations are potentially the key factor in further reducing computing time. Consequently, current research aims to provide a method for the rapid prediction of widely varying scenarios. In this work artificial neural networks (ANN) are trained and compared to approximate the system behavior of the probabilistic simulation model. To do so, information needs to be sampled from the probabilistic simulation in an efficient way. Because only a limited space in the whole design space of the 16 independent variables is of interest, a classification is developed. Finally it required only around 35 minutes to create the regression models, including sampling the design space, simulating the training data and training the ANNs. The resulting ANNs are able to predict all scenarios within the validity range of the regression model with a coefficient of determination of over 0.9998 for independent test data (1.051.200 data points). They need only a few milliseconds to predict one scenario, enabling in-depth analysis in a brief period of time.}, language = {en} } @article{PriesmannMuenchTillmannsetal.2024, author = {Priesmann, Jan and M{\"u}nch, Justin and Tillmanns, Marius and Ridha, E. and Spiegel, Thomas and Reich, Marius and Adam, Mario and Nolting, L. and Praktiknjo, Aaron}, title = {Artificial intelligence and design of experiments for resource adequacy assessment in power systems}, series = {Energy Strategy Reviews}, volume = {53}, journal = {Energy Strategy Reviews}, publisher = {Elsevier}, issn = {2211-467X}, doi = {10.1016/j.esr.2024.101368}, year = {2024}, language = {en} }