@inproceedings{19738, author = {{Wende, Marc and Philippi, Kai and Kenig, Eugeny}}, booktitle = {{10. ProcessNet-Jahrestagung und 34. DECHEMA-Jahrestagung der Biotechnologen }}, location = {{Aachen}}, title = {{{Numerische Simulation von Gravidestillationsapparaten zur Trennung eines binären Ethanol/Wasser-Gemisches}}}, year = {{2020}}, } @inproceedings{19739, author = {{Szopinski, Daniel}}, booktitle = {{Proceedings of the 15th International Conference on Design Science Research in Information Systems and Technology (DESRIST)}}, location = {{Virtual Conference/Workshop}}, title = {{{Active Business Model Development Tools: Design Requirements}}}, year = {{2020}}, } @inproceedings{19741, author = {{Szopinski, Daniel}}, booktitle = {{Proceedings of the 41st International Conference on Information Systems (ICIS)}}, location = {{Virtual Conference/Workshop}}, title = {{{Exploring design principles for stimuli in business model development tools}}}, year = {{2020}}, } @phdthesis{19743, author = {{Ditter, Jan}}, isbn = {{978-3-8440-7530-4}}, title = {{{Methodenentwicklung zum Entfügen von Stahl-Klebverbindungen bei tiefen Temperaturen}}}, year = {{2020}}, } @article{19753, author = {{Ditter, Jan and Aubel, Tobias and Meschut, Gerson}}, journal = {{adhesion ADHESIVES + SEALANTS}}, number = {{1}}, title = {{{Simple Determination of Fast Curing Parameters for Bonded Structures}}}, year = {{2020}}, } @inproceedings{19782, author = {{Müller, Michelle and Neumann, Jürgen and Gutt, Dominik and Kundisch, Dennis}}, booktitle = {{Proceedings of the 41th International Conference on Information Systems (ICIS)}}, location = {{Virtual Conference/Workshop}}, title = {{{Toss a Coin to your Host - How Guests End up Paying for the Cost of Regulatory Policies}}}, year = {{2020}}, } @article{19823, abstract = {{Individual grains of chalcopyrite solar cell absorbers can facet in different crystallographic directions at their surfaces. To gain a deeper understanding of the junction formation in these devices, we correlate variations in the surface facet orientation with the defect electronic properties. We use a combined analytical approach based on scanning tunneling spectroscopy (STS), scanning electron microscopy, and electron back scatter diffraction (EBSD), where we perform these experiments on identical surface areas as small as 2 × 2 µm2 with a lateral resolution well below 50 nm. The topography of the absorber surfaces indicates two main morphological features: micro-faceted, long basalt-like columns and their short nano-faceted terminations. Our STS results reveal that the long columns exhibit spectral signatures typical for the presence of pronounced oxidation-induced surface dipoles in conjunction with an increased density of electronic defect levels. In contrast, the nano-faceted terminations of the basalt-like columns are largely passivated in terms of electronic defect levels within the band gap region. Corresponding crystallographic data based on EBSD experiments show that the surface of the basalt-like columns can be assigned to intrinsically polar facet orientations, while the passivated terminations are assigned to non-polar planes. Ab-initio calculations suggest that the polar surfaces are more prone to oxidation and resulting O-induced defects, in comparison to non-polar planes. Our results emphasize the correlation between morphology, surface facet orientations and surface electronic properties. Furthermore, this work aids in gaining a fundamental understanding of oxidation induced lateral inhomogeneities in view of the p-n junction formation in chalcopyrite thin-film solar cells.}}, author = {{Elizabeth, Amala and Conradi, Hauke and K. Sahoo, Sudhir and Kodalle, Tim and A. Kaufmann, Christian and Kühne, Thomas and Mirhosseini, Hossein and Abou-Ras, Daniel and Mönig, Harry}}, issn = {{1359-6454}}, journal = {{Acta Materialia}}, keywords = {{Chalcopyrite absorber, Scanning tunneling spectroscopy, Electron backscatter diffraction, Density functional theory, Surface dipole}}, title = {{{Correlating facet orientation, defect-level density and dipole layer formation at the surface of polycrystalline CuInSe2 thin films}}}, doi = {{https://doi.org/10.1016/j.actamat.2020.09.028}}, volume = {{200}}, year = {{2020}}, } @article{19864, author = {{Meyer, Maurice and Frank, Maximilian and Massmann, Melina and Dumitrescu, Roman}}, journal = {{Proceedings of The 11th International Multi-Conference on Complexity, Informatics and Cybernetics (IMCIC 2020)}}, title = {{{Research and Consulting in Data-Driven Strategic Product Planning}}}, year = {{2020}}, } @article{19866, author = {{Meyer, Maurice and Frank, Maximilian and Massmann, Melina and Dumitrescu, Roman}}, journal = {{Journal of Systemics, Cybernetics and Informatics}}, number = {{2}}, pages = {{55--61}}, title = {{{Research and Consulting in Data-Driven Strategic Product Planning}}}, volume = {{18}}, year = {{2020}}, } @article{19895, author = {{Steiger, Sören and Pelster, Matthias}}, issn = {{0167-2681}}, journal = {{Journal of Economic Behavior & Organization}}, pages = {{503--522}}, title = {{{Social interactions and asset pricing bubbles}}}, doi = {{10.1016/j.jebo.2020.09.020}}, volume = {{179}}, year = {{2020}}, } @inproceedings{19899, abstract = {{Most existing robot formation problems seek a target formation of a certain minimal and, thus, efficient structure. Examples include the Gathering and the Chain-Formation problem. In this work, we study formation problems that try to reach a maximal structure, supporting for example an efficient coverage in exploration scenarios. A recent example is the NASA Shapeshifter project, which describes how the robots form a relay chain along which gathered data from extraterrestrial cave explorations may be sent to a home base. As a first step towards understanding such maximization tasks, we introduce and study the Max-Chain-Formation problem, where $n$ robots are ordered along a winding, potentially self-intersecting chain and must form a connected, straight line of maximal length connecting its two endpoints. We propose and analyze strategies in a discrete and in a continuous time model. In the discrete case, we give a complete analysis if all robots are initially collinear, showing that the worst-case time to reach an $\varepsilon$-approximation is upper bounded by $\mathcal{O}(n^2 \cdot \log (n/\varepsilon))$ and lower bounded by $\Omega(n^2 \cdot~\log (1/\varepsilon))$. If one endpoint of the chain remains stationary, this result can be extended to the non-collinear case. If both endpoints move, we identify a family of instances whose runtime is unbounded. For the continuous model, we give a strategy with an optimal runtime bound of $\Theta(n)$. Avoiding an unbounded runtime similar to the discrete case relies crucially on a counter-intuitive aspect of the strategy: slowing down the endpoints while all other robots move at full speed. Surprisingly, we can show that a similar trick does not work in the discrete model.}}, author = {{Castenow, Jannik and Kling, Peter and Knollmann, Till and Meyer auf der Heide, Friedhelm}}, booktitle = {{Stabilization, Safety, and Security of Distributed Systems - 22nd International Symposium, SSS 2020, Austin, Texas, USA, November 18-21, 2020, Proceedings}}, editor = {{Devismes , Stéphane and Mittal, Neeraj }}, isbn = {{978-3-030-64347-8}}, pages = {{65--80}}, publisher = {{Springer}}, title = {{{A Discrete and Continuous Study of the Max-Chain-Formation Problem – Slow Down to Speed Up}}}, doi = {{10.1007/978-3-030-64348-5_6}}, volume = {{12514}}, year = {{2020}}, } @article{19938, abstract = {{We show that symplectic integrators preserve bifurcations of Hamiltonian boundary value problems and that nonsymplectic integrators do not. We provide a universal description of the breaking of umbilic bifurcations by nonysmplectic integrators. We discover extra structure induced from certain types of boundary value problems, including classical Dirichlet problems, that is useful to locate bifurcations. Geodesics connecting two points are an example of a Hamiltonian boundary value problem, and we introduce the jet-RATTLE method, a symplectic integrator that easily computes geodesics and their bifurcations. Finally, we study the periodic pitchfork bifurcation, a codimension-1 bifurcation arising in integrable Hamiltonian systems. It is not preserved by either symplectic on nonsymplectic integrators, but in some circumstances symplecticity greatly reduces the error. }}, author = {{McLachlan, Robert I and Offen, Christian}}, journal = {{Foundations of Computational Mathematics}}, number = {{6}}, pages = {{1363--1400}}, title = {{{Preservation of Bifurcations of Hamiltonian Boundary Value Problems Under Discretisation}}}, doi = {{10.1007/s10208-020-09454-z}}, volume = {{20}}, year = {{2020}}, } @article{19939, author = {{Kreusser, Lisa Maria and McLachlan, Robert I and Offen, Christian}}, issn = {{0951-7715}}, journal = {{Nonlinearity}}, number = {{5}}, pages = {{2335--2363}}, title = {{{Detection of high codimensional bifurcations in variational PDEs}}}, doi = {{10.1088/1361-6544/ab7293}}, volume = {{33}}, year = {{2020}}, } @phdthesis{19947, abstract = {{Ordinary differential equations (ODEs) and partial differential equations (PDEs) arise in most scientific disciplines that make use of mathematical techniques. As exact solutions are in general not computable, numerical methods are used to obtain approximate solutions. In order to draw valid conclusions from numerical computations, it is crucial to understand which qualitative aspects numerical solutions have in common with the exact solution. Symplecticity is a subtle notion that is related to a rich family of geometric properties of Hamiltonian systems. While the effects of preserving symplecticity under discretisation on long-term behaviour of motions is classically well known, in this thesis (a) the role of symplecticity for the bifurcation behaviour of solutions to Hamiltonian boundary value problems is explained. In parameter dependent systems at a bifurcation point the solution set to a boundary value problem changes qualitatively. Bifurcation problems are systematically translated into the framework of classical catastrophe theory. It is proved that existing classification results in catastrophe theory apply to persistent bifurcations of Hamiltonian boundary value problems. Further results for symmetric settings are derived. (b) It is proved that to preserve generic bifurcations under discretisation it is necessary and sufficient to preserve the symplectic structure of the problem. (c) The catastrophe theory framework for Hamiltonian ODEs is extended to PDEs with variational structure. Recognition equations for A-series singularities for functionals on Banach spaces are derived and used in a numerical example to locate high-codimensional bifurcations. (d) The potential of symplectic integration for infinite-dimensional Lie-Poisson systems (Burgers’ equation, KdV, fluid equations, . . . ) using Clebsch variables is analysed. It is shown that the advantages of symplectic integration can outweigh the disadvantages of integrating over a larger phase space introduced by a Clebsch representation. (e) Finally, the preservation of variational structure of symmetric solutions in multisymplectic PDEs by multisymplectic integrators on the example of (phase-rotating) travelling waves in the nonlinear wave equation is discussed.}}, author = {{Offen, Christian}}, publisher = {{Massey University}}, title = {{{Analysis of Hamiltonian boundary value problems and symplectic integration}}}, year = {{2020}}, } @inproceedings{19953, abstract = {{Current GNN architectures use a vertex neighborhood aggregation scheme, which limits their discriminative power to that of the 1-dimensional Weisfeiler-Lehman (WL) graph isomorphism test. Here, we propose a novel graph convolution operator that is based on the 2-dimensional WL test. We formally show that the resulting 2-WL-GNN architecture is more discriminative than existing GNN approaches. This theoretical result is complemented by experimental studies using synthetic and real data. On multiple common graph classification benchmarks, we demonstrate that the proposed model is competitive with state-of-the-art graph kernels and GNNs.}}, author = {{Damke, Clemens and Melnikov, Vitaly and Hüllermeier, Eyke}}, booktitle = {{Proceedings of the 12th Asian Conference on Machine Learning (ACML 2020)}}, editor = {{Jialin Pan, Sinno and Sugiyama, Masashi}}, keywords = {{graph neural networks, Weisfeiler-Lehman test, cycle detection}}, location = {{Bangkok, Thailand}}, pages = {{49--64}}, publisher = {{PMLR}}, title = {{{A Novel Higher-order Weisfeiler-Lehman Graph Convolution}}}, volume = {{129}}, year = {{2020}}, } @misc{19999, author = {{Mayer, Stefan}}, publisher = {{Universität Paderborn}}, title = {{{Optimierung von JMCTest beim Testen von Inter Method Contracts}}}, year = {{2020}}, } @inproceedings{20116, author = {{Nouri, Zahra and Wachsmuth, Henning and Engels, Gregor}}, booktitle = {{Proceedings of COLING 2020, the 28th International Conference on Computational Linguistics}}, location = {{Barcelona, Spain}}, pages = {{6264--6276}}, title = {{{Mining Crowdsourcing Problems from Discussion Forums of Workers}}}, year = {{2020}}, } @inproceedings{20122, author = {{El Baff, Roxanne and Al-Khatib, Khalid and Stein, Benno and Wachsmuth, Henning}}, booktitle = {{Third Workshop on Computational Modeling of People's Opinions, Personality, and Emotions in Social Media (PEOPLES 2020)}}, pages = {{29--40}}, title = {{{Persuasiveness of News Editorials depending on Ideology and Personality}}}, year = {{2020}}, } @inbook{20123, author = {{Herzig, Bardo and Martin, Alexander and Klar, Tilman-Mathies}}, booktitle = {{Deutsch Digital. Band 1 Theorie (2. Aufl.)}}, editor = {{Knopf, Julia and Abraham, Ulf}}, isbn = {{978-3-8340-2048-2}}, pages = {{108--135}}, title = {{{Mobile Medien – Medienpädagogische und technische Grundlagen, Potential für den Deutschunterricht und Beispiele.}}}, year = {{2020}}, } @techreport{20131, author = {{Kundisch, Dennis and Beverungen, Daniel}}, pages = {{22--26}}, title = {{{Als Wirtschaftsinformatiker die digitale Transformation in Organisationen gestalten}}}, year = {{2020}}, }