@article{ValeroChansonBung2020, author = {Valero, Daniel and Chanson, Hubert and Bung, Daniel Bernhard}, title = {Robust estimators for free surface turbulence characterization: A stepped spillway application}, series = {Flow Measurement and Instrumentation}, volume = {76}, journal = {Flow Measurement and Instrumentation}, number = {Art. 101809}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0955-5986}, doi = {10.1016/j.flowmeasinst.2020.101809}, year = {2020}, abstract = {Robust estimators are parameters insensitive to the presence of outliers. However, they presume the shape of the variables' probability density function. This study exemplifies the sensitivity of turbulent quantities to the use of classic and robust estimators and the presence of outliers in turbulent flow depth time series. A wide range of turbulence quantities was analysed based upon a stepped spillway case study, using flow depths sampled with Acoustic Displacement Meters as the flow variable of interest. The studied parameters include: the expected free surface level, the expected fluctuation intensity, the depth skewness, the autocorrelation timescales, the vertical velocity fluctuation intensity, the perturbations celerity and the one-dimensional free surface turbulence spectrum. Three levels of filtering were utilised prior to applying classic and robust estimators, showing that comparable robustness can be obtained either using classic estimators together with an intermediate filtering technique or using robust estimators instead, without any filtering technique.}, language = {en} } @article{UlmerBraunChengetal.2020, author = {Ulmer, Jessica and Braun, Sebastian and Cheng, Chi-Tsun and Dowey, Steve and Wollert, J{\"o}rg}, title = {Human-Centered Gamification Framework for Manufacturing Systems}, series = {Procedia CIRP}, volume = {93}, journal = {Procedia CIRP}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2212-8271}, doi = {10.1016/j.procir.2020.04.076}, pages = {670 -- 675}, year = {2020}, abstract = {While bringing new opportunities, the Industry 4.0 movement also imposes new challenges to the manufacturing industry and all its stakeholders. In this competitive environment, a skilled and engaged workforce is a key to success. Gamification can generate valuable feedbacks for improving employees' engagement and performance. Currently, Gamification in workspaces focuses on computer-based assignments and training, while tasks that require manual labor are rarely considered. This research provides an overview of Enterprise Gamification approaches and evaluates the challenges. Based on that, a skill-based Gamification framework for manual tasks is proposed, and a case study in the Industry 4.0 model factory is shown.}, language = {en} } @inproceedings{BedburMoorkampPetersonetal.2020, author = {Bedbur, Christian and Moorkamp, Wilfried and Peterson, Leif Arne and Uibel, Thomas}, title = {Holzbr{\"u}cken mit Natursteinbel{\"a}gen - Untersuchungen zur Aktivierung der Verbundwirkung}, series = {Doktorandenkolloquium Holzbau Forschung + Praxis 2020}, booktitle = {Doktorandenkolloquium Holzbau Forschung + Praxis 2020}, editor = {Kuhlmann, Ulrike}, publisher = {Universit{\"a}t Stuttgart, Institut f{\"u}r Konstruktion und Entwurf}, address = {Stuttgart}, pages = {53 -- 60}, year = {2020}, language = {de} } @article{EveraersKarimiVarzanehFlecketal.2020, author = {Everaers, Ralf and Karimi-Varzaneh, Hossein Ali and Fleck, Franz and Hojdis, Nils and Svaneborg, Carsten}, title = {Kremer-Grest Models for Commodity Polymer Melts: Linking Theory, Experiment, and Simulation at the Kuhn Scale}, series = {Macromolecules}, volume = {53}, journal = {Macromolecules}, number = {6}, publisher = {ACS Publications}, address = {Washington, DC}, issn = {1520-5835}, doi = {10.1021/acs.macromol.9b02428}, pages = {1901 -- 1916}, year = {2020}, abstract = {The Kremer-Grest (KG) polymer model is a standard model for studying generic polymer properties in molecular dynamics simulations. It owes its popularity to its simplicity and computational efficiency, rather than its ability to represent specific polymers species and conditions. Here we show that by tuning the chain stiffness it is possible to adapt the KG model to model melts of real polymers. In particular, we provide mapping relations from KG to SI units for a wide range of commodity polymers. The connection between the experimental and the KG melts is made at the Kuhn scale, i.e., at the crossover from the chemistry-specific small scale to the universal large scale behavior. We expect Kuhn scale-mapped KG models to faithfully represent universal properties dominated by the large scale conformational statistics and dynamics of flexible polymers. In particular, we observe very good agreement between entanglement moduli of our KG models and the experimental moduli of the target polymers.}, language = {en} } @misc{OhrtmannGolland2020, author = {Ohrtmann, Jan-Peter and Golland, Alexander}, title = {Daten- und Privatsph{\"a}reschutz im Wandel der 2020er-Jahre}, pages = {33 -- 38}, year = {2020}, language = {de} } @inproceedings{LorenzAltherrPelz2020, author = {Lorenz, Imke-Sophie and Altherr, Lena and Pelz, Peter F.}, title = {Assessing and Optimizing the Resilience of Water Distribution Systems Using Graph-Theoretical Metrics}, series = {Operations Research Proceedings 2019}, booktitle = {Operations Research Proceedings 2019}, editor = {Neufeld, Janis S. and Buscher, Udo and Lasch, Rainer and M{\"o}st, Dominik and Sch{\"o}nberger, J{\"o}rn}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-48439-2}, doi = {10.1007/978-3-030-48439-2_63}, pages = {521 -- 527}, year = {2020}, abstract = {Water distribution systems are an essential supply infrastructure for cities. Given that climatic and demographic influences will pose further challenges for these infrastructures in the future, the resilience of water supply systems, i.e. their ability to withstand and recover from disruptions, has recently become a subject of research. To assess the resilience of a WDS, different graph-theoretical approaches exist. Next to general metrics characterizing the network topology, also hydraulic and technical restrictions have to be taken into account. In this work, the resilience of an exemplary water distribution network of a major German city is assessed, and a Mixed-Integer Program is presented which allows to assess the impact of capacity adaptations on its resilience.}, language = {en} } @inproceedings{LeiseSimonAltherr2020, author = {Leise, Philipp and Simon, Nicolai and Altherr, Lena}, title = {Comparison of Piecewise Linearization Techniques to Model Electric Motor Efficiency Maps: A Computational Study}, series = {Operations Research Proceedings 2019}, booktitle = {Operations Research Proceedings 2019}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-48439-2}, doi = {10.1007/978-3-030-48439-2_55}, pages = {457 -- 463}, year = {2020}, abstract = {To maximize the travel distances of battery electric vehicles such as cars or buses for a given amount of stored energy, their powertrains are optimized energetically. One key part within optimization models for electric powertrains is the efficiency map of the electric motor. The underlying function is usually highly nonlinear and nonconvex and leads to major challenges within a global optimization process. To enable faster solution times, one possibility is the usage of piecewise linearization techniques to approximate the nonlinear efficiency map with linear constraints. Therefore, we evaluate the influence of different piecewise linearization modeling techniques on the overall solution process and compare the solution time and accuracy for methods with and without explicitly used binary variables.}, language = {en} } @article{MeyerHaenelBeehetal.2020, author = {Meyer, S. and H{\"a}nel, Matthias and Beeh, B. and Dittmann-Gabriel, S{\"o}ren and Dluhosch, R. and May, Martin and Herrmann, Ulf}, title = {Multifunktionaler thermischer Stromspeicher f{\"u}r die Strom- und W{\"a}rmeversorgung der Industrie von morgen}, series = {ETG Journal / Energietechnische Gesellschaft im VDE (ETG)}, volume = {2020}, journal = {ETG Journal / Energietechnische Gesellschaft im VDE (ETG)}, number = {1}, issn = {2625-9907}, pages = {6 -- 9}, year = {2020}, language = {de} } @inproceedings{SattlerChicoCaminosAttietal.2020, author = {Sattler, Johannes Christoph and Chico Caminos, Ricardo Alexander and Atti, Vikrama Nagababu and {\"U}rlings, Nicolas and Dutta, Siddharth and Ruiz, Victor and Kalogirou, Soteris and Ktistis, Panayiotis and Agathokleous, Rafaela and Alexopoulos, Spiros and Teixeira Boura, Cristiano Jos{\´e} and Herrmann, Ulf}, title = {Dynamic simulation tool for a performance evaluation and sensitivity study of a parabolic trough collector system with concrete thermal energy storage}, series = {AIP Conference Proceedings 2303}, booktitle = {AIP Conference Proceedings 2303}, publisher = {American Institute of Physics}, address = {Melville, NY}, issn = {0094-243X}, doi = {10.1063/5.0029277}, pages = {160004}, year = {2020}, language = {de} } @article{Olbertz2020, author = {Olbertz, Klaus}, title = {Jahresr{\"u}ckblick Arbeitsrecht 2019 : Gesetzes{\"a}nderungen und insbesondere im Zeichen des Befristungs- und Urlaubsrechts stehende h{\"o}chstrichterliche Rechtsprechung}, series = {NWB - Steuer- und Wirtschaftsrecht}, journal = {NWB - Steuer- und Wirtschaftsrecht}, number = {8}, publisher = {NWB-Verl.}, address = {Herne}, issn = {0028-3460}, pages = {557 -- 569}, year = {2020}, abstract = {In Fortschreibung des Jahresr{\"u}ckblicks 2018 (Olbertz, NWB 5/2019 S. 266 ) skizziert der vorliegende Beitrag die j{\"u}ngsten nennenswerten Entwicklungen im Arbeitsrecht des Jahres 2019. Im Bereich der Gesetzgebung, mit dem sich der erste Teil des Beitrags befasst, betrifft dies etwa das Fachkr{\"a}fteeinwanderungsgesetz, die angestoßenen Schutzvorschriften f{\"u}r Whistleblower oder das gesetzlich verankerte Recht auf Br{\"u}ckenteilzeit. In der arbeitsrechtlichen h{\"o}chstrichterlichen Rechtsprechung stand das Jahr 2019 insbesondere im Zeichen des Befristungs- und des Urlaubsrechts. Was hier und dar{\"u}ber hinaus wegweisend war, zeigt der zweite Teil des Beitrags.}, language = {de} } @article{Olbertz2020, author = {Olbertz, Klaus}, title = {GmbH-Gesch{\"a}ftsf{\"u}hrer: das eine Mal Arbeitnehmer, das andere Mal nicht : Arbeits- und sozialrechtliche Anwendung von Schutzvorschriften auf den Gesch{\"a}ftsf{\"u}hrer von A bis Z}, series = {NWB - Steuer- und Wirtschaftsrecht}, journal = {NWB - Steuer- und Wirtschaftsrecht}, number = {19}, publisher = {NWB-Verl.}, address = {Herne}, issn = {0028-3460}, pages = {1431 -- 1441}, year = {2020}, language = {de} } @article{Olbertz2020, author = {Olbertz, Klaus}, title = {Wenn der „leitende" Angestellte doch nur ein „normaler" Arbeitnehmer ist ... : Zur Rechtsstellung leitender Angestellter, zu Fehleinsch{\"a}tzungen des Arbeitgebers und Praxishinweisen}, series = {NWB - Steuer- und Wirtschaftsrecht}, journal = {NWB - Steuer- und Wirtschaftsrecht}, number = {32}, publisher = {NWB-Verl.}, address = {Herne}, issn = {0028-3460}, pages = {2397 -- 2406}, year = {2020}, language = {de} } @article{JungStaat2020, author = {Jung, Alexander and Staat, Manfred}, title = {Erratum to "Modeling and simulation of human induced pluripotent stem cell-derived cardiac tissue" [GAMM-Mitteilungen, (2019), 42, 4, 10.1002/gamm.201900002]}, series = {GAMM-Mitteilungen}, volume = {43}, journal = {GAMM-Mitteilungen}, number = {4}, publisher = {Wiley-VCH GmbH}, address = {Weinheim}, issn = {1522-2608}, doi = {10.1002/gamm.202000011}, year = {2020}, language = {en} } @book{Timme2020, author = {Timme, Michael}, title = {WEG - Wohnungeigentumsgesetz / Hrsg. von Michael Timme . Stand 01.02.2020 ; Edition: 40}, publisher = {Beck}, address = {M{\"u}nchen}, year = {2020}, language = {de} } @book{Timme2020, author = {Timme, Michael}, title = {WEG - Wohnungeigentumsgesetz / Hrsg. von Michael Timme . Stand: 01.05.2020 ; Edition 41}, publisher = {Beck}, address = {M{\"u}nchen}, year = {2020}, language = {de} } @inproceedings{MeckMuellerAltherretal.2020, author = {Meck, Marvin M. and M{\"u}ller, Tim M. and Altherr, Lena and Pelz, Peter F.}, title = {Improving an industrial cooling system using MINLP, considering capital and operating costs}, series = {Operations Research Proceedings 2019}, booktitle = {Operations Research Proceedings 2019}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-48438-5 (Print)}, doi = {10.1007/978-3-030-48439-2_61}, pages = {505 -- 512}, year = {2020}, abstract = {The chemical industry is one of the most important industrial sectors in Germany in terms of manufacturing revenue. While thermodynamic boundary conditions often restrict the scope for reducing the energy consumption of core processes, secondary processes such as cooling offer scope for energy optimisation. In this contribution, we therefore model and optimise an existing cooling system. The technical boundary conditions of the model are provided by the operators, the German chemical company BASF SE. In order to systematically evaluate different degrees of freedom in topology and operation, we formulate and solve a Mixed-Integer Nonlinear Program (MINLP), and compare our optimisation results with the existing system.}, language = {en} } @article{MuellerLeiseLorenzetal.2020, author = {M{\"u}ller, Tim M. and Leise, Philipp and Lorenz, Imke-Sophie and Altherr, Lena and Pelz, Peter F.}, title = {Optimization and validation of pumping system design and operation for water supply in high-rise buildings}, series = {Optimization and Engineering}, volume = {2021}, journal = {Optimization and Engineering}, number = {22}, publisher = {Springer}, issn = {1573-2924}, doi = {10.1007/s11081-020-09553-4}, pages = {643 -- 686}, year = {2020}, abstract = {The application of mathematical optimization methods for water supply system design and operation provides the capacity to increase the energy efficiency and to lower the investment costs considerably. We present a system approach for the optimal design and operation of pumping systems in real-world high-rise buildings that is based on the usage of mixed-integer nonlinear and mixed-integer linear modeling approaches. In addition, we consider different booster station topologies, i.e. parallel and series-parallel central booster stations as well as decentral booster stations. To confirm the validity of the underlying optimization models with real-world system behavior, we additionally present validation results based on experiments conducted on a modularly constructed pumping test rig. Within the models we consider layout and control decisions for different load scenarios, leading to a Deterministic Equivalent of a two-stage stochastic optimization program. We use a piecewise linearization as well as a piecewise relaxation of the pumps' characteristics to derive mixed-integer linear models. Besides the solution with off-the-shelf solvers, we present a problem specific exact solving algorithm to improve the computation time. Focusing on the efficient exploration of the solution space, we divide the problem into smaller subproblems, which partly can be cut off in the solution process. Furthermore, we discuss the performance and applicability of the solution approaches for real buildings and analyze the technical aspects of the solutions from an engineer's point of view, keeping in mind the economically important trade-off between investment and operation costs.}, language = {en} } @inproceedings{MuellerAltherrLeiseetal.2020, author = {M{\"u}ller, Tim M. and Altherr, Lena and Leise, Philipp and Pelz, Peter F.}, title = {Optimization of pumping systems for buildings: Experimental validation of different degrees of model detail on a modular test rig}, series = {Operations Research Proceedings 2019}, booktitle = {Operations Research Proceedings 2019}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-48438-5}, doi = {10.1007/978-3-030-48439-2_58}, pages = {481 -- 488}, year = {2020}, abstract = {Successful optimization requires an appropriate model of the system under consideration. When selecting a suitable level of detail, one has to consider solution quality as well as the computational and implementation effort. In this paper, we present a MINLP for a pumping system for the drinking water supply of high-rise buildings. We investigate the influence of the granularity of the underlying physical models on the solution quality. Therefore, we model the system with a varying level of detail regarding the friction losses, and conduct an experimental validation of our model on a modular test rig. Furthermore, we investigate the computational effort and show that it can be reduced by the integration of domain-specific knowledge.}, language = {en} } @article{EckertAbbasiMangetal.2020, author = {Eckert, Alexander and Abbasi, Mozhdeh and Mang, Thomas and Saalw{\"a}chter, Kay and Walther, Andreas}, title = {Structure, Mechanical Properties, and Dynamics of Polyethylenoxide/Nanoclay Nacre-Mimetic Nanocomposites}, series = {Macromolecules}, volume = {53}, journal = {Macromolecules}, number = {5}, publisher = {ACS Publications}, address = {Washington, DC}, issn = {1520-5835}, doi = {10.1021/acs.macromol.9b01931}, pages = {1716 -- 1725}, year = {2020}, abstract = {Nacre-mimetic nanocomposites based on high fractions of synthetic high-aspect-ratio nanoclays in combination with polymers are continuously pushing boundaries for advanced material properties, such as high barrier against oxygen, extraordinary mechanical behavior, fire shielding, and glass-like transparency. Additionally, they provide interesting model systems to study polymers under nanoconfinement due to the well-defined layered nanocomposite arrangement. Although the general behavior in terms of forming such layered nanocomposite materials using evaporative self-assembly and controlling the nanoclay gallery spacing by the nanoclay/polymer ratio is understood, some combinations of polymer matrices and nanoclay reinforcement do not comply with the established models. Here, we demonstrate a thorough characterization and analysis of such an unusual polymer/nanoclay pair that falls outside of the general behavior. Poly(ethylene oxide) (PEO) and sodium fluorohectorite form nacre-mimetic, lamellar nanocomposites that are completely transparent and show high mechanical stiffness and high gas barrier, but there is only limited expansion of the nanoclay gallery spacing when adding increasing amounts of polymer. This behavior is maintained for molecular weights of PEO varied over four orders of magnitude and can be traced back to depletion forces. By careful investigation via X-ray diffraction and proton low-resolution solid-state NMR, we are able to quantify the amount of mobile and immobilized polymer species in between the nanoclay galleries and around proposed tactoid stacks embedded in a PEO matrix. We further elucidate the unusual confined polymer dynamics, indicating a relevant role of specific surface interactions.}, language = {en} } @article{EggertMoulen2020, author = {Eggert, Mathias and Moulen, Tobias}, title = {Selektion von Gesch{\"a}ftsprozessen zur Anwendung von Robotic Process Automation am Beispiel einer Versicherung}, series = {HMD Praxis der Wirtschaftsinformatik}, volume = {57}, journal = {HMD Praxis der Wirtschaftsinformatik}, number = {6}, publisher = {Springer}, address = {Weinheim}, issn = {1436-3011}, doi = {10.1365/s40702-020-00665-0}, pages = {1150 -- 1162}, year = {2020}, abstract = {H{\"a}ufig bremsen geringe IT-Ressourcen, fehlende Softwareschnittstellen oder eine veraltete und komplex gewachsene Systemlandschaft die Automatisierung von Gesch{\"a}ftsprozessen. Robotic Process Automation (RPA) ist eine vielversprechende Methode, um Gesch{\"a}ftsprozesse oberfl{\"a}chenbasiert und ohne gr{\"o}ßere Systemeingriffe zu automatisieren und Medienbr{\"u}che abzubauen. Die Auswahl der passenden Prozesse ist dabei f{\"u}r den Erfolg von RPA-Projekten entscheidend. Der vorliegende Beitrag liefert daf{\"u}r Selektionskriterien, die aus einer qualitativen Inhaltanalyse von elf Interviews mit RPA-Experten aus dem Versicherungsumfeld resultieren. Das Ergebnis umfasst eine gewichtetet Liste von sieben Dimensionen und 51 Prozesskriterien, welche die Automatisierung mit Softwarerobotern beg{\"u}nstigen bzw. deren Nichterf{\"u}llung eine Umsetzung erschweren oder sogar verhindern. Die drei wichtigsten Kriterien zur Auswahl von Gesch{\"a}ftsprozessen f{\"u}r die Automatisierung mittels RPA umfassen die Entlastung der an dem Prozess mitwirkenden Mitarbeiter (Arbeitnehmer{\"u}berlastung), die Ausf{\"u}hrbarkeit des Prozesses mittels Regeln (Regelbasierte Prozessteuerung) sowie ein positiver Kosten-Nutzen-Vergleich. Praktiker k{\"o}nnen diese Kriterien verwenden, um eine systematische Auswahl von RPA-relevanten Prozessen vorzunehmen. Aus wissenschaftlicher Perspektive stellen die Ergebnisse eine Grundlage zur Erkl{\"a}rung des Erfolgs und Misserfolgs von RPA-Projekten dar.}, language = {de} }