TY - THES AB - 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. AU - Offen, Christian ID - 19947 TI - Analysis of Hamiltonian boundary value problems and symplectic integration ER - TY - CONF AB - 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. AU - Damke, Clemens AU - Melnikov, Vitaly AU - Hüllermeier, Eyke ED - Jialin Pan, Sinno ED - Sugiyama, Masashi ID - 19953 KW - graph neural networks KW - Weisfeiler-Lehman test KW - cycle detection T2 - Proceedings of the 12th Asian Conference on Machine Learning (ACML 2020) TI - A Novel Higher-order Weisfeiler-Lehman Graph Convolution VL - 129 ER - TY - CONF AU - Spliethöver, Maximilian AU - Wachsmuth, Henning ID - 20139 T2 - Proceedings of the 7th Workshop on Argument Mining (ArgMining 2020) TI - Argument from Old Man's View: Assessing Social Bias in Argumentation ER - TY - JOUR AU - Otroshi, Mortaza AU - Meschut, Gerson ID - 20170 IS - 7/20 JF - Umformtechnik Blech Rohre Profile SN - 0300-3167 TI - Spannungszustandsabhängige Schädigungsmodellierung zum Halbhohlstanznieten ER - TY - GEN AU - Hemsen, Paul AU - Hesse, Marc AU - Löken, Nils AU - Nouri, Zahra ID - 20191 T2 - 2nd Crowdworking Symposium TI - Platform-independent Reputation and Qualification System for Crowdwork ER - TY - GEN AB - In many real-world applications, the relative depth of objects in an image is crucial for scene understanding, e.g., to calculate occlusions in augmented reality scenes. Predicting depth in monocular images has recently been tackled using machine learning methods, mainly by treating the problem as a regression task. Yet, being interested in an order relation in the first place, ranking methods suggest themselves as a natural alternative to regression, and indeed, ranking approaches leveraging pairwise comparisons as training information ("object A is closer to the camera than B") have shown promising performance on this problem. In this paper, we elaborate on the use of so-called \emph{listwise} ranking as a generalization of the pairwise approach. Listwise ranking goes beyond pairwise comparisons between objects and considers rankings of arbitrary length as training information. Our approach is based on the Plackett-Luce model, a probability distribution on rankings, which we combine with a state-of-the-art neural network architecture and a sampling strategy to reduce training complexity. An empirical evaluation on benchmark data in a "zero-shot" setting demonstrates the effectiveness of our proposal compared to existing ranking and regression methods. AU - Lienen, Julian AU - Hüllermeier, Eyke ID - 20211 T2 - arXiv:2010.13118 TI - Monocular Depth Estimation via Listwise Ranking using the Plackett-Luce model ER - TY - JOUR AB - The challenge of designing new tunable nonlinear dielectric materials with tailored properties has attracted an increasing amount of interest recently. Herein, we study the effective nonlinear dielectric response of a stochastic paraelectric-dielectric composite consisting of equilibrium distributions of circular and partially penetrable disks (or parallel, infinitely long, identical, partially penetrable, circular cylinders) of a dielectric phase randomly dispersed in a continuous matrix of a paraelectric phase. The random microstructures were generated using the Metropolis Monte Carlo algorithm. The evaluation of the effective permittivity and tunability were carried out by employing either a Landau thermodynamic model or its Johnson’s approximation to describe the field-dependent permittivity of the paraelectric phase and solving continuum-electrostatics equations using finite element calculations. We reveal that the percolation threshold in this composite governs the critical behavior of the effective permittivity and tunability. For microstructures below the percolation threshold, our simulations demonstrate a strong nonlinear behaviour of the field-dependent effective permittivity and very high tunability that increases as a function of dielectric phase concentration. Above the percolation threshold, the effective permittivity shows the tendency to linearization and the tunability dramatically drops down. The highly reduced permittivity and extraordinarily high tunability are obtained for the composites with dielectric impenetrable disks at high concentrations, in which the triggering of the percolation transition is avoided. The reported results cast light on distinct nonlinear behaviour of 2D and 3D stochastic composites and can guide the design of novel composites with the controlled morphology and tailored permittivity and tunability. AU - Myroshnychenko, Viktor AU - Smirnov, Stanislav AU - Jose, Pious Mathews Mulavarickal AU - Brosseau, Christian AU - Förstner, Jens ID - 20233 JF - Acta Materialia SN - 1359-6454 TI - Nonlinear dielectric properties of random paraelectric-dielectric composites VL - 203 ER - TY - THES AU - Homt, Martina ID - 28416 TI - Die Anbahnung einer forschenden Grundhaltung im Praxissemester – eine empirische Analyse von Bedingungen und Entwicklungsverläufen ER - TY - JOUR AU - Engels, Gregor ID - 29045 JF - Gruppe. Interaktion. Organisation. Zeitschrift für Angewandte Organisationspsychologie (GIO) SN - 2366-6145 TI - Der digitale Fußabdruck, Schatten oder Zwilling von Maschinen und Menschen ER - TY - GEN AB - Previous accounting research shows that taxes affect decision making by individuals and firms. Most studies assume that agents have an accurate perception regarding their tax burden. However, there is a growing body of literature analyzing whether taxes are indeed perceived correctly. We review 127 studies on the measurement of tax misperception and its behavioral implications. The review reveals that many taxpayers have substantial tax misperceptions that lead to biased decision making. We develop a Behavioral Taxpayer Response Model on the impact of provided tax information on tax perception. Besides individual traits, characteristics of the tax information and the decision environment determine the extent of tax misperception. We discuss opportunities for future research and methodological limitations. While there is much evidence on tax misperception at the individual level, we hardly find any research at the firm level. Little is known about the real effects of managers’ tax misperception and on how tax information is strategically managed to impact stakeholders. This research gap is surprising as a large part of the accounting literature analyzes decision making and disclosure of firms. We recommend a mixed-method approach combining experiments, surveys, and archival data analyses to improve the knowledge on tax misperception and its consequences. AU - Blaufus, Kay AU - Chirvi, Malte AU - Huber, Hans-Peter AU - Maiterth, Ralf AU - Sureth-Sloane, Caren ID - 21406 TI - Tax Misperception and Its Effects on Decision Making - a Literature Review VL - No. 39 ER - TY - GEN AU - Bornemann, Tobias AU - Schipp, Adrian AU - Sureth-Sloane, Caren ID - 21407 TI - 2018/2019 Umfrage zur Steuerkomplexität in deutschen Finanzverwaltungen ER - TY - GEN AB - European regulation mandates public country-by-country reporting for banks and is expected to increase reputational costs in case of tax haven activities. We test whether the availability of additional public information on the locations of banks' subsidiaries reduces their tax haven presence. In a preliminary difference-in-difference analysis we find that indeed, tax haven presence in “Dot-Havens” has declined significantly after the introduction of mandatory public country-by-country reporting for European banks, as compared to the insurance industry which is not subject to this regulation. AU - Eberhartinger, Eva AU - Speitmann, Raffael AU - Sureth-Sloane, Caren ID - 21409 TI - Real Effects of Public Country-by-Country Reporting and the Firm Structure of European Banks VL - #2020-01 ER - TY - GEN AB - We analyze the impact of trust on bargaining behavior between auditor and auditee in a tax setting. We study the effect of interpersonal trust and trust in government on both taxpayer and tax auditor. In an experiment with variation in pairwise trust settings, we find evidence that both kinds of trust affect the bargaining behavior, albeit in different ways. While trust in government increases taxpayers’ tax offers, interpersonal trust may lead to more concessionary behavior of tax auditors moderated by trust in government. Our findings help tax authorities to shape programs to enhance compliance in an atmosphere of trust. AU - Eberhartinger, Eva AU - Speitmann, Raffael AU - Sureth-Sloane, Caren ID - 21410 TI - How Does Trust Affect Concessionary Behavior in Tax Bargaining? VL - No. 41 ER - TY - GEN AB - This study examines the visibility of the GAAP effective tax rate (ETR) in firms’ financial statements as a distinct disclosure choice. Applying a game-theory disclosure model for voluntary disclosure strategies of firms to a tax setting, we argue that firms face a trade-off in their ETR disclosure decisions. On the one hand, firms have an incentive to enhance their ETR disclosure when the ratio offers shareholders “favourable conditions”, for example in terms of higher expected after-tax cash-flows. On the other hand, the disclosure of a favourable low ETR could attract the attention of tax auditors and the public and ultimately result in disclosure costs. We empirically test disclosure behaviour by examining the relation between disclosure visibility and different ETR conditions that reflect different stakeholder specific costs and benefits. While we find that unfavourable ETR conditions are not highlighted, we observe higher disclosure visibility for favourable ETRs (smooth, close to the industry average, decreasing). Additional analyses reveal that this high visibility is characteristic of firm-years with only moderately decreasing ETRs at usual ETR levels, while extreme ETRs are not highlighted. Interestingly and in contrast to our main results, a subsample of family firms do not seem to highlight favourable ETRs. AU - Flagmeier, Vanessa AU - Müller, Jens AU - Sureth-Sloane, Caren ID - 21411 TI - When Do Firms Highlight Their Effective Tax Rate? VL - No. 37 ER - TY - GEN AU - Heile, Vanessa AU - Huber, Hans-Peter AU - Maiterth, Ralf AU - Sureth-Sloane, Caren ID - 21414 TI - Umfrage: Steuerliche Verwaltungskosten, steuerliche Corona-Soforthilfemaßnahmen und Investitionen in der Krise ER - TY - GEN AB - This article comprehensively reviews Australia’s corporate income tax complexity as faced by multinational corporations (MNCs) and compares it to the average of the remaining OECD countries. Building on unique survey data, I find that the Australian tax code is considerably more complex than the OECD average, which is mainly due to overly complex anti-avoidance legislation, such as regulations on transfer pricing, general anti-avoidance or controlled foreign corporations (CFC). In contrast, Australia’s tax framework, which covers processes and features such as tax law enactment or tax audits, is close to the OECD average. A more granular analysis yields further interesting insights. For example, excessive details in the tax code and the time between the announcement of a tax law change and its enactment turn out to be serious issues in Australia relative to the remaining OECD countries. AU - Hoppe, Thomas ID - 21416 TI - Tax Complexity in Australia - A Survey-Based Comparison to the OECD Average VL - No. 14 ER - TY - GEN AU - Hoppe, Thomas AU - Schanz, Deborah AU - Schipp, Adrian AU - Siegel, Felix AU - Sturm, Susann AU - Sureth-Sloane, Caren ID - 21417 TI - 2018 Global MNC Tax Complexity Survey ER - TY - GEN AB - This paper introduces an index that comprehensively measures the complexity of countries’ corporate income tax systems faced by multinational corporations. It builds on surveys of highly experienced tax consultants of the largest international tax services networks. The index, called the Tax Complexity Index (TCI), is composed of a tax code subindex covering tax regulations and a tax framework subindex covering tax processes and features. For a sample of 100 countries, we find that tax complexity varies considerably across countries, and tax code and framework complexity also vary within countries. Among others, tax complexity is strongly driven by the complexity of transfer pricing regulations in the tax code and tax audits in the tax framework. When analyzing the associations with other country characteristics, we identify different patterns. For example, with regard to GDP, we find a positive association with tax code complexity and a negative association with tax framework complexity, suggesting that highly economically developed countries tend to have more complex tax codes and less complex frameworks. Overall, our tax complexity measures can serve as valuable proxies in future research and supportive tools for a variety of firm decisions and national and international tax policy discussions. AU - Hoppe, Thomas AU - Schanz, Deborah AU - Sturm, Susann AU - Sureth-Sloane, Caren ID - 21418 TI - Measuring Tax Complexity Across Countries: A Survey Study on MNCs VL - No. 5 ER - TY - GEN AB - This paper analyzes the association between tax complexity and foreign direct investments (FDI) based on the newly developed Tax Complexity Index (TCI) and its components. For a sample of 15,607 new foreign subsidiaries, we find no association between total tax complexity, as proxied by the TCI, and the location probability. When we decompose the TCI into tax code complexity and tax framework complexity, we find opposing associations. Tax code complexity is positively related to the location probability, while tax framework complexity is negatively related to it. These associations are, for example, driven by the complexity of transfer pricing and loss offset regulations in the tax code and the dimensions guidance, audits, as well as filing and payments, in the tax framework. In additional analyses, we find that the associations are sensitive to certain characteristics, such as country-specific and firm-specific characteristics. For example, the positive tax code association diminishes when tax rates are high. Overall, we are the first to provide empirical evidence on potential cost-benefit tradeoffs of tax complexity for FDI and thereby enhance prior literature, which has primarily focused on the costs of tax complexity. AU - Hoppe, Thomas AU - Schanz, Deborah AU - Sturm, Susann AU - Sureth-Sloane, Caren AU - Voget, Johannes ID - 21419 TI - The Relation between Tax Complexity and Foreign Direct Investments: Evidence Across Countries VL - No. 13 ER - TY - JOUR AU - Sureth-Sloane, Caren ID - 21422 IS - 5 JF - AWV-Informationen TI - Steuerkomplexität als Standortfaktor. So komplex ist das Steuersystem in Deutschland ER -