Working Papers/Reports
Recent Submissions
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On the Kauffman bracket skein module of (S^1×S^2) # (S^1×S^2)
(2024)arXivDetermining the structure of the Kauffman bracket skein module of all $3$-manifolds over the ring of Laurent polynomials $\mathbb Z[A^{\pm 1}]$ is a big open problem in skein theory. Very little is known about the skein module of non-prime manifolds over this ring. In this paper, we compute the Kauffman bracket skein module of the $3$-manifold $(S^1 \times S^2) \ \# \ (S^1 \times S^2)$ over the ring $\mathbb Z[A^{\pm 1}]$. We do this by ...Working Paper -
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A Two-Scale Effective Model for Defect-Induced Localization Transitions in Non-Hermitian Systems
(2024)SAM Research ReportWe illuminate the fundamental mechanism responsible for the transition between the non-Hermitian skin effect and defect-induced localization in the bulk. We study a Hamiltonian with non-reciprocal couplings that exhibits the skin effect (the localization of all eigenvectors at one edge) and add an on-site defect in the center. Using a two-scale asymptotic method, we characterize the long-scale growth and decay of the eigenvectors and ...Report -
Regularized dynamical parametric approximation
(2024)SAM Research ReportThis paper studies the numerical approximation of evolution equations by nonlinear parametrizations \(u(t)=\Phi(q(t))\) with time-dependent parameters \(q(t)\), which are to be determined in the computation. The motivation comes from approximations in quantum dynamics by multiple Gaussians and approximations of various dynamical problems by tensor networks and neural networks. In all these cases, the parametrization is typically irregular: ...Report -
Tunable Localisation in Parity-Time-Symmetric Resonator Arrays with Imaginary Gauge Potentials
(2024)SAM Research ReportThe aim of this paper is to illustrate both analytically and numerically the interplay of two fundamentally distinct non-Hermitian mechanisms in a deep subwavelength regime. Considering a parity-time symmetric system of one-dimensional subwavelength resonators equipped with two kinds of non-Hermiticity — an imaginary gauge potential and on-site gain and loss — we prove that all but two eigenmodes of the system pass through exceptional ...Report -
Exponential Convergence of hp-ILGFEM for semilinear elliptic boundary value problems with monomial reaction
(2024)SAM Research ReportWe study the fully explicit numerical approximation of a semilinear elliptic boundary value model problem, which features a monomial reaction and analytic forcing, in a bounded polygon \(\Omega\subset\mathbb{R}^2\) with a finite number of straight edges. In particular, we analyze the convergence of \(hp\)-type iterative linearized Galerkin (\(hp\)-ILG) solvers. Our convergence analysis is carried out for conforming \(hp\)-finite element ...Report -
Capacitance Size of Active Power Filter: Buck-Type vs. Split DC Link
(2024)In this working paper the size of the required capacitance of an active power decoupling / active power filter for a single phase rectifier is evaluated based on power flow considerations.Working Paper -
Coupled Boundary and Volume Integral Equations for Electromagnetic Scattering
(2024)SAM Research ReportWe study frequency domain electromagnetic scattering at a bounded, penetrable, and inhomogeneous obstacle \(\Omega \subset \mathbb{R}^3\). From the Stratton-Chu integral representation, we derive a new representation formula when constant reference coefficients are given for the interior domain. The resulting integral representation contains the usual layer potentials, but also volume potentials on \(\Omega\). Then it is possible to ...Report -
Bike network planning in limited urban space
(2024)arXivThe lack of cycling infrastructure in urban environments hinders the adoption of cycling as a viable mode for commuting, despite the evident benefits of (e-)bikes as sustainable, efficient, and health-promoting transportation modes. Bike network planning is a tedious process, relying on heuristic computational methods that frequently overlook the broader implications of introducing new cycling infrastructure, in particular the necessity ...Working Paper -
Analysis of Continuous-time Robust Control Models using Finite, Sampled, Experimental Data
(1995)Center for Control Engineering & Computation. Technical ReportThe application of robust control theory requires applicable models containing unknown, bounded, perturbations and unknown, bounded input signals. Model validation is a quantitative means of assessing the applicability of a given model with respect to experimental data. This paper develops a theoretical framework, and a computational solution, for the model validation problem in the case where the model, including unknown perturbations ...Report -
Success factors of growth-stage digital health companies: protocol for a systematic literature review
(2024)medRxivBackground The healthcare industry is undergoing rapid transformation and progress, fueled by technological advances and the growing need for accessible, affordable, and high-quality healthcare services. While there has been significant progress in digitizing healthcare, especially during the COVID-19 pandemic, there is still considerable untapped potential for digital therapeutics (DTx). According to a report by Bloomberg, the digital ...Working Paper -
Dynamic electric breakdown modeling of quasi-uniform, dielectric-bounded gas gaps
(2024)The motivating problem for this paper is the determination of the probability of breakdown of small (< mm) quasi-uniform, dielectric-bounded air gaps under short transient voltages (some ns to us). Guidelines for answering this question are of importance in many areas of applied plasma physics, ranging from new spark ignition concepts with ultrashort high-voltage pulses (consistent high breakdown voltage desired) to the avoidance of the ...Working Paper -
X-BASE: the first terrestrial carbon and water flux products from an extended data-driven scaling framework, FLUXCOM-X
(2024)EGUsphereMapping in-situ eddy covariance measurements of terrestrial land-atmosphere fluxes to the globe is a key method for diagnosing the Earth system from a data-driven perspective. We describe the first global products (called X-BASE) from a newly implemented up-scaling framework, FLUXCOM-X. The X-BASE products comprise of estimates of CO2 net ecosystem exchange (NEE), gross primary productivity (GPP) as well as evapotranspiration (ET) and, ...Working Paper -
Steuerbelastung der Reichen in der Schweiz: Eine vergleichende Analyse aufgrund verschiedener Modellrechnungen
(2024)KOF StudiesDie vorliegende Auswertung im Auftrag von Oxfam Deutschland e. V. und dem Netzwerk Steuergerechtigkeit zeigt anhand einer Reihe von Modellhaushalten beispielhaft auf, wie hoch die Steuerbelastung in der Schweiz für reiche und sehr reiche Steuerzahler ist, und wie diese im Vergleich zu einer mittelständischen Familie ausfällt. Wie in anderen Ländern haben Millionärs- und Milliardärsfamilien Möglich-keiten, ihre Einkommen aus Unternehmensanteilen ...Report -
Collaboration and Innovation Patterns in Diabetes Ecosystems
(2024)medRxivBackground: The global prevalence of diabetes is increasing and has stimulated new technological advancements in disease management. Although there are many digital health companies with a focus on diabetes, building them up at scale is difficult due to a heterogeneous, inefficient, and fragmented healthcare system. While ecosystems, or collaborative value creation, could help address system fragmentation; the current diabetes ecosystem ...Working Paper -
Digital Health Technologies for Metabolic Disorders in Older Adults: A Scoping Review Protocol
(2024)medRxivIntroduction: Metabolic disorders (type 2 diabetes, insulin resistance, hyperglycemia, obesity, hyperlipidemia, hypertension, nonalcoholic fatty liver disease, and metabolic syndrome) are leading causes of mortality and disability worldwide and disproportionately affect older adults relative to those younger. Digital health technologies (DHTs), such as patient monitoring, digital diagnostics, and digital therapeutics, emerge as promising ...Working Paper -
Wearables and smartphones for modifiable risk factors in metabolic health: a scoping review protocol
(2024)medRxivBackground: Metabolic diseases, such as cardiovascular diseases and diabetes, contribute significantly to global mortality and disability. Wearable devices and smartphones increasingly track physiological and lifestyle risk factors and can improve the management of metabolic diseases. However, the absence of clear guidelines for deriving meaningful signals from these devices often hampers cross-study comparisons. Objective: Thus, this ...Working Paper -
The Unintended Consequences of Pandemic Lockdowns: Evidence on Domestic Violence in Italy
(2024)Center for Law & Economics Working Paper SeriesThis study examines the effects of Italy’s COVID-19 tiered lockdown system on domestic violence. The policy implemented categorizes regions into different weekly risk levels, imposing corresponding mobility restrictions—the higher the risk, the greater the constraints on mobility outside the home. Leveraging this setting, we employ a difference-in-differences approach with staggered treatment adoption and heterogeneous treatment effects ...Working Paper