cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Towards an Ontology For a Smart and Adaptive Prosthesis Service System Framework
Creators: name: Patiniott, Nicholas
name: Borg, Jonathan
name: Francalanza, Emmanuel
name: Zammit, Joseph
name: Vella, Pierre
name: Gatt, Alfred
name: Paetzold-Byhain, Kristin
Publisher: name: Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
Year: 2023
Subjects: Product Service Systems (PSS)
User-centered Design
Collaborative Design
Smart Prosthesis
Patient-Centered Design

description: Amputees face a number of challenges when acquiring and using a prosthesis, with major issues being the cost of the device, the time it takes for their custom prosthesis to be developed and delivered, as well as the challenges they face to get it regularly serviced and maintained. The other stakeholders involved, including the prosthetists and standard systems manufacturers, have a difficulty to collectively handle and resolve so many different issues that occur to the different amputees. A detailed analysis of these challenges was performed by our research team [1], [2] and key relationships and interactions between these challenges and how they relate to the stakeholders were determined. Particular attention was given to the relationship between the amputee and their prosthesis. To further address these challenges, our research reported in this paper contributes an ontological model (titled The adProLiSS Ontological Model) to address these challenges. Our adProLiSS Ontological Model is the backbone from which key up-to-date data may be collected from a smart prosthesis and securely transmitted to a Prosthesis Digital Twin Model, where the data will be processed and converted into useful information that the stakeholder (e.g. prosthetist and/or amputee) can use. By having this information at hand at any given point in time, the health of the amputee and their prosthesis can be monitored, maintained and adapted. This will allow the amputee to an aftercare service and prosthesis that continually adapts to their ever-changing needs.
Deep Learning-based Grading of Coronary Artery Disease from Coronary CT Angiography Scans
Creators: name: Denzinger, Felix
Publisher: name: Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
Year: 2024

description: One of the deadliest disease types in modern societies is coronary artery disease (CAD). It is often related to coronary artery plaques aggregating within the vessel wall obstructing the lumen causing a stenosis. To support physicians this thesis aims to answer the following research question: Can we perform an automated CAD assessment from coronary CT angiography (CCTA) scans using machine learning (ML)? To answer this question, we tackle three main tasks: First, we develop deep learning (DL)-based methods capable of predicting a significant stenosis degree and whether a lesion leads to a revascularization procedure. Four approaches with different characteristics are developed on this task, striving for a prior knowledge induced data representation and ML method design. Depending on whether a prior segmentation step is performed or not we reach an area under the receiver operating characteristic curve (AUC) of 0.96/0.92 for significant stenosis detection and 0.88/0.90 for the revascularization decision target with/without the segmentation. As a second task, methods to automatically determine the coronary artery disease-reporting data system (CAD-RADS) score – a patient-level CAD severity score – is developed. We leverage the best performing approach from the first task and embed it in a taskspecific hierarchical architecture to aggregate single coronary subsegment features to allow a patient-level prediction. This approach is enhanced with a synergizing heuristic centerline labeling approach and auxiliary targets to reach an AUC of 0.942, 0.950 on the task of finding patients with CAD and on the task of detecting patients with an obstructive CAD respectively. With this strong performance, we tackle a third task of evaluating the clinical applicability of our CAD-RADS scoring approach. In a first step, we examine how changing some commonly altered CCTA image formation parameters influences the predictions of our approach. Here, we find that the overall performance stays on a high level, but predictions for individual patients changes. From this we conclude a need to create a more robust approach with respect to technical variation. In a second step, we develop an approach to automatically detect a norm variant of the coronaries, as out-of-domain samples may adversely impact ML-based CAD grading systems. On this task, we achieve a strong performance with an AUC of around 0.938. Additionally, we propose a quantile-based abstention approach, as an automated CAD grading system should know when a decision is better left to the human reader. Overall, this thesis concludes that – with limitations – its main research question can be answered with a “Yes”. A well-performing CAD grading system was developed, but future work on robustness with respect to technical variation, the handling of anatomical outliers and explainability of the method at hand remain on the horizon.
Collision trajectories and regularisation of two-body problem on $S^2$
Creators: name: Arsie, Alessandro
name: Balabanova, Nataliya A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Dynamical Systems (math.DS)
subject: FOS: Mathematics

description: In this paper, we investigate collision orbits of two identical bodies placed on the surface of a two-dimensional sphere and interacting via an attracting potential of the form $V(q)=-\cot(q)$, where $q$ is the angle formed by the position vectors of the two bodies. We describe the $ω$-limit set of the variables in the symplectically reduced system corresponding to initial data that lead to collisions. Furthermore we provide a geometric description of the dynamics. Lastly, we regularise the system and investigate its behaviour on near collision orbits. This involves the study of completely degenerate equilibria and the use of high-dimensional non-homogenous blow-ups.
Bandit-Based Model Selection for Deformable Object Manipulation
Creators: name: McConachie, Dale
name: Berenson, Dmitry
Publisher: name: arXiv
Year: 2017
Subjects: subject: Robotics (cs.RO)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: We present a novel approach to deformable object manipulation that does not rely on highly-accurate modeling. The key contribution of this paper is to formulate the task as a Multi-Armed Bandit problem, with each arm representing a model of the deformable object. To "pull" an arm and evaluate its utility, we use the arm's model to generate a velocity command for the gripper(s) holding the object and execute it. As the task proceeds and the object deforms, the utility of each model can change. Our framework estimates these changes and balances exploration of the model set with exploitation of high-utility models. We also propose an approach based on Kalman Filtering for Non-stationary Multi-armed Normal Bandits (KF-MANB) to leverage the coupling between models to learn more from each arm pull. We demonstrate that our method outperforms previous methods on synthetic trials, and performs competitively on several manipulation tasks in simulation.
description: Presented at the Workshop on the Algorithmic Foundations of Robotics, 2016, San Francisco, CA
Computertomographie-basierte Bestimmung der linksventrikulären Funktionsparameter: Einfluss von Matrixgröße, Anzahl der rekonstruierten Phasen und Schichtdicke
Creators: name: Steinmann, Bettine
Publisher: name: Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
Year: 2024
Subjects: Kardio CT
Linksventrikuläre Funktion
CT Rekonstruktionsparameter

description: Unterschucht wurde der Einfluss der Rekonstruktionsparameter Matrixgröße, Anzahl der rekonstruierten Phasen und Schichtdicke bei der Bestimmung der LV-Funktionsparameter mittels eines Dual-Source CT Scanners der dritten Generation.
Tambour de bravade "Bacchas" datant du Premier Empire avec sa paire de baguettes
Creators: name: Musée National Des Arts Et Traditions Populaires (Paris)
name: Centre D'ethnologie Française
Publisher: name: École des Hautes Études en Sciences Sociales; Institut  interdisciplinaire d'anthropologie du contemporain (Paris); Laboratoire d'anthropologie et d'histoire de l'institution de la culture (Paris)
Year: 2024

Abstract
Homogenization of the vibro-acoustic transmission on periodically perforated elastic plates interacting with flow
Creators: name: Rohan, Eduard
name: Lukeš, Vladimír
Publisher: name: arXiv
Year: 2022
Subjects: subject: Analysis of PDEs (math.AP)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 35B27, 74Q05, 74F10

description: We consider acoustic waves propagating in an inviscid fluid interacting with a rigid periodically perforated plate in the presence of permanent flows. The paper presents a model of an acoustic interface obtained by the asymptotic homogenization of a thin transmission layer in which the plate is embedded. To account for the flow, a decomposition of the fluid pressure and velocity in the steady and fluctuating parts is employed. This enables for a linearization and an efficient use of the homogenization method which leads to a model order reduction effect. The dependence of an extended Helmholtz equation on the permanent flow introduces a locally periodic velocity field in the perforated plate vicinity, so that the coefficients of the homogenized interface depend on the flow. The derived model extended by natural coupling conditions provides an implicit Dirichlet-to-Neumann operator. Numerical simulations of wave propagation in a waveguide illustrate the flow speed influence on the acoustic transmission. Also some geometrical aspects are explored.
Intersection Warning System for Occlusion Risks using Relational Local Dynamic Maps
Creators: name: Damerow, Florian
name: Li, Yuda
name: Puphal, Tim
name: Flade, Benedict
name: Eggert, Julian
Publisher: name: arXiv
Year: 2023
Subjects: subject: Robotics (cs.RO)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: This work addresses the task of risk evaluation in traffic scenarios with limited observability due to restricted sensorial coverage. Here, we concentrate on intersection scenarios that are difficult to access visually. To identify the area of sight, we employ ray casting on a local dynamic map providing geometrical information and road infrastructure. Based on the area with reduced visibility, we first model scene entities that pose a potential risk without being visually perceivable yet. Then, we predict a worst-case trajectory in the survival analysis for collision risk estimation. Resulting risk indicators are utilized to evaluate the driver's current behavior, to warn the driver in critical situations, to give suggestions on how to act safely or to plan safe trajectories. We validate our approach by applying the resulting intersection warning system on real world scenarios. The proposed system's behavior reveals to mimic the general behavior of a correctly acting human driver.
Tra la parete e la pagina. L'arte per la fotografia nell'Italia degli anni Trenta.
Creators: name: Catalano, Maria Ida
Publisher: name: Zenodo
Year: 2018

description: Catalano, M.I. Tra la parete e la pagina. L’arte per la fotografia nell’Italia degli anni Trenta. In: (a cura di): Enrico Menduni, Lorenzo Marmo, Fotografia e culture visuali del XXI secolo.
 ROMA : RomaTrE-Press, 2018, pp.123-132 (ISBN: 978-88-94885-84-2)
Correspondence theorems for Hopf algebroids with applications to affine groupoids
Creators: name: Kaoutit, Laiachi El
name: Ghobadi, Aryan
name: Saracco, Paolo
name: Vercruysse, Joost
Publisher: name: arXiv
Year: 2022
Subjects: subject: Rings and Algebras (math.RA)
subject: Algebraic Geometry (math.AG)
subject: Quantum Algebra (math.QA)
subject: FOS: Mathematics

description: We provide a correspondence between one-sided coideal subrings and one-sided ideal two-sided coideals in an arbitrary bialgebroid. We prove that, under some expected additional conditions, this correspondence becomes bijective for Hopf algebroids. As an application, we investigate normal Hopf ideals in commutative Hopf algebroids (affine groupoid schemes) in connection with the study of normal affine subgroupoids.
Massive flows in AdS$_6$/CFT$_5$
Creators: name: Akhond, Mohammad
name: Legramandi, Andrea
name: Nunez, Carlos
name: Santilli, Leonardo
name: Schepers, Lucas
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study five-dimensional ${\cal N}=1$ Superconformal Field Theories of the linear quiver type. These are deformed by a relevant operator, corresponding to a homogeneous mass term for certain matter fields. The free energy is calculated at arbitrary values of the mass parameter. After a careful regularisation procedure, the result can be put in correspondence with a calculation in the supergravity dual background. The F-theorem is verified for these flows, both in field theory and in supergravity. This letter presents some of the results in the companion paper arXiv:2211.13240.
description: Seven pages, two figures. v2: Minor improvements and references added. v3: Clarifications added, published version
Matrix Models and Holography: Mass Deformations of Long Quiver Theories in 5d and 3d
Creators: name: Akhond, Mohammad
name: Legramandi, Andrea
name: Nunez, Carlos
name: Santilli, Leonardo
name: Schepers, Lucas
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We enlarge the dictionary between matrix models for long linear quivers preserving eight supercharges in $d=5$ and $d=3$ and type IIB supergravity backgrounds with AdS$_{d+1}$ factors. We introduce mass deformations of the field theory that break the quiver into a collection of interacting linear quivers, which are decoupled at the end of the RG flow. We find and solve a Laplace problem in supergravity which realises these deformations holographically. The free energy and expectation values of antisymmetric Wilson loops are calculated on both sides of the proposed duality, finding agreement. Our matching procedure sheds light on the F-theorem in five dimensions.
description: 46 pages plus appendices. Various figures. Some improvements and references added. SciPost Physics version
Recurrence network measures for hypothesis testing using surrogate data: application to black hole light curves
Creators: name: Jacob, Rinku
name: Harikrishnan, K. P.
name: Misra, R.
name: Ambika, G.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: Recurrence networks and the associated statistical measures have become important tools in the analysis of time series data. In this work, we test how effective the recurrence network measures are in analyzing real world data involving two main types of noise, white noise and colored noise. We use two prominent network measures as discriminating statistic for hypothesis testing using surrogate data for a specific null hypothesis that the data is derived from a linear stochastic process. We show that the characteristic path length is especially efficient as a discriminating measure with the conclusions reasonably accurate even with limited number of data points in the time series. We also highlight an additional advantage of the network approach in identifying the dimensionality of the system underlying the time series through a convergence measure derived from the probability distribution of the local clustering coefficients. As examples of real world data, we use the light curves from a prominent black hole system and show that a combined analysis using three primary network measures can provide vital information regarding the nature of temporal variability of light curves from different spectroscopic classes.
description: 30 pages, 15 figures, to appear in Communications in Nonlinear Science and Numerical Simulation
High‑resolution label‑free mapping of murine kidney vasculature by raster‑scanning optoacoustic mesoscopy: an ex vivo study
Hochauflösende, kontrastmittelfreie Darstellung des Gefäßsystems von Mäusennieren mittels optoakustischer Mesoskopie
Creators: name: Göbel, Colin
Publisher: name: Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
Year: 2024
Subjects: RSOM, OAI, Kidney

description: Abstract Background: Chronic kidney disease (CKD) is a global burden affecting both children and adults. Novel imaging modalities hold great promise to visualize and quantify structural, functional, and molecular organ damage. The aim of the study was to visualize and quantify murine renal vasculature using label-free raster scanning optoacoustic mesoscopy (RSOM) in explanted organs from mice with renal injury. Material and methods: For the experiments, freshly bisected kidneys of alpha 8 integrin knock-out (KO) and wildtype mice (WT) were used. A total of n=7 female (n=4 KO, n=3 WT) and n=6 male animals (n=2 KO, n=4 WT) aged 6 weeks were examined with RSOM optoacoustic imaging systems (RSOM Explorer P50 at SWL 532nm and/ or ms-P50 imaging system at 532 nm, 555 nm, 579 nm, and 606 nm). Images were reconstructed using a dedicated software, analyzed for size and vascular area and compared to standard histologic sections. Results: RSOM enabled mapping of murine kidney size and vascular area, revealing differences between kidney sizes of male (m) and female (f ) mice (merged frequencies (MF) f vs. m: 52.42±6.24 mm2 vs. 69.18±15.96 mm2, p=0.0156) and absolute vascular area (MF f vs. m: 35.67±4.22 mm2 vs. 49.07±13.48 mm2, p=0.0036). Without respect to sex, the absolute kidney area was found to be smaller in knock-out (KO) than in wildtype (WT) mice (WT vs. KO: MF: p=0.0255) and showed a similar trend for the relative vessel area (WT vs. KO: MF p=0.0031). Also the absolute vessel areas of KO compared to WT were found significantly different (MF p=0.0089). A significant decrease in absolute vessel area was found in KO compared to WT male mice (MF WT vs. KO: 54.37±9.35 mm2 vs. 34.93±13.82 mm2, p=0.0232). In addition, multispectral RSOM allowed visualization of oxygenated and deoxygenated parenchymal regions by spectral unmixing. Conclusion: This study demonstrates the capability of RSOM for label-free visualization of differences in vascular morphology in ex vivo murine renal tissue at high resolution. Due to its scalability optoacoustic imaging provides an emerging modality with potential for further preclinical and clinical imaging applications.
La Corte di giustizia. Ruoli, mentalità, ideologie
Creators: name: Sotis Carlo
Publisher: name: Zenodo
Year: 2018
Subjects: antroplogia giuridica diritto penale europeo

description: SOTIS C (2018). La Corte di giustizia. Ruoli, mentalità, ideologie. In: (a cura di): Guarnieri G Insolera G Zilletti L, Giurisdizioni europee e sistemi nazionali. Tendenze e criticità . p. 53-72, ROMA:Carocci Editore, ISBN: 9788843091089
An experimental verification of the one-dimensional static Willis-form equations
Creators: name: Yao, R. W.
name: Gao, H. X.
name: Sun, Y. X.
name: Yuan, X. D.
name: Xiang, Z. H.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences
subject: 74B10 (Primary), 74A20 (Secondary)

description: This paper investigates the behavior of a heavy soft spring in steady circular motion. Since the spring is inhomogeneous due to centrifugal force, one can rigorously prove that it follows the one-dimensional static Willis-form equations. The theoretical predictions agree very well with experimental results. It further demonstrates that these equations can give a clear understanding of the stress-stiffening and spin-softening effect. These findings reveal that the Willis-form equations can give very accurate linear approximations of finite deformation problems and are also helpful to clarify the classical concept of the principle of material frame indifference.
description: 35 pages, 13 figures
Adaptive Weight Assignment Scheme For Multi-task Learning
Creators: name: Huq, Aminul
name: Pervin, Mst Tasnim
Publisher: name: arXiv
Year: 2023
Subjects: subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Deep learning based models are used regularly in every applications nowadays. Generally we train a single model on a single task. However, we can train multiple tasks on a single model under multi-task learning settings. This provides us many benefits like lesser training time, training a single model for multiple tasks, reducing overfitting, improving performances etc. To train a model in multi-task learning settings we need to sum the loss values from different tasks. In vanilla multi-task learning settings we assign equal weights but since not all tasks are of similar difficulty we need to allocate more weight to tasks which are more difficult. Also improper weight assignment reduces the performance of the model. We propose a simple weight assignment scheme in this paper which improves the performance of the model and puts more emphasis on difficult tasks. We tested our methods performance on both image and textual data and also compared performance against two popular weight assignment methods. Empirical results suggest that our proposed method achieves better results compared to other popular methods.
On the reduced Bernstein-Sato polynomial of Thom-Sebastiani singularities
Creators: name: Domínguez, Alberto Castaño
name: Macarro, Luis Narváez
Publisher: name: arXiv
Year: 2022
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 14F10, 32C38

description: Given two holomorphic functions $f$ and $g$ defined in two respective germs of complex analytic manifolds $(X,x)$ and $(Y,y)$, we know thanks to M. Saito that, as long as one of them is Euler homogeneous, the reduced (or microlocal) Bernstein-Sato polynomial of the Thom-Sebastiani sum $f+g$ can be expressed in terms of those of $f$ and $g$. In this note we give a purely algebraic proof of a similar relation between the whole functional equations that can be applied to any setting (not necessarily analytic) in which Bernstein-Sato polynomials can be defined.
description: 8 pages, final version
Negative bulk modulus and possibility of loss of elastic stability near tricritical transitions in thin films on substrates
Creators: name: Levanyuk, A. P.
name: Minyukov, S. A.
name: Misirlioglu, I. B.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Within the Landau-like approach we study anomalies of elastic moduli at phase transitions in thin films on substrates. We consider the case where, similar to many experimental cases, the first-order transition in free crystal would convert into a second order in the film if the system remained homogeneous. It is shown, however, that apart from its questionable thermodynamic profitability, the homogeneous state of low-symmetry phase may become absolutely unstable which is signaled by changing of sign of its bulk modulus.
description: 17 pages, 3 figures
Bridging Coherence Optics and Classical Mechanics -- A Universal Light Polarization-Entanglement Complementary Relation
Creators: name: Qian, Xiaofeng
name: Izadi, Misagh
Publisher: name: arXiv
Year: 2022
Subjects: subject: Optics (physics.optics)
subject: Classical Physics (physics.class-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: While optics and mechanics are two distinct branches of physics, they are connected. It is well known that geometrical/ray treatment of light has direct analogies to mechanical descriptions of particle motion. However, connections between coherence wave optics and classical mechanics are rarely reported. Here we explore links of the two for an arbitrary light field by performing a quantitative analysis of two optical coherence properties: polarization and entanglement (implied by a wave picture of light due to Huygens and Fresnel). A universal complementary identity relation is obtained. More surprisingly, optical polarization, entanglement, and their identity relation are shown to be quantitatively associated with mechanical concepts of center of mass and moment of inertia through the Huygens-Steiner theorem for rigid body rotation. The obtained result bridges coherence wave optics and classical mechanics through the two theories of Huygens.
description: 6 pages, 2 figures
Lebendzellaufnahmen mit einem aufrechten Lichtmikroskop zur Detektion von physiologischen oder tumorösen Zellvorgängen und deren Interaktion mit Bestrahlung und Medikamenten
Creators: name: Vu, Jennifer
Publisher: name: Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
Year: 2024
Subjects: Lebendzellmikroskopie, CiC, NSCLC, Gliome

description: Es handelt sich um eine experimentelle Arbeit zur Etablierung von kostengünstigen Lebendzellaufnahmen mit einem Lichtmikroskop. Verschiedene Versuchsreihen wurden dafür untersucht. Die Zellen der verschiedenen Versuchsreihen wurden mit Fluoreszenzfarbstoffen beimpft und es wurden Bildaufnahmen über einen Zeitraum von ca. 3-5 Tagen aufgenommen. Es wurden dabei drei Konditionen untersucht: Mitochondrien-, Nekrose- und Apoptoseaktivität. Ausgewertet konnte man schließlich die einzelnen Daten in diversen Diagrammen darstellen.
Fuzzy $CP^2$ Space-Times
Creators: name: Chaney, A.
name: Stern, A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Four-dimensional manifolds with changing signature are obtained by taking the large $N$ limit of fuzzy $CP^2$ solutions to a Lorentzian matrix model. The regions of Lorentzian signature give toy models of closed universes which exhibit cosmological singularities. These singularities are resolved at finite $N$, as the underlying $CP^2$ solutions are expressed in terms of finite matrix elements.
description: 14 pages, 3 figures
Finite-Volume Corrections to Electromagnetic Masses for Larger-Than-Physical Electric Charges
Creators: name: Matzelle, Matthew E.
name: Tiburzi, Brian C.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: The numerical value of the fine-structure constant generally leads to small isospin-breaking effects due to electromagnetism in QCD. This smallness complicates determining isospin breaking from lattice QCD computations that include electromagnetism. One solution to this problem consists of performing computations using larger-than-physical values of the electric charge, and subsequently extrapolating (or interpolating) to the physical value of the fine-structure constant. Motivated by recent lattice QCD + QED computations of electromagnetic masses employing this setup, we consider finite-volume effects arising from the use of larger-than-physical electric charges. A modified power-counting scheme, which is based on treating the fine-structure constant as larger than its physical value, is explored. Results for perturbative QED corrections, however, are surprising. Within the framework of non-relativistic QED, multi-loop diagrams exhibit a momentum factorization property that produces exact cancellations. We determine that power-law finite-volume effects vanish at the leading two- and three-loop order, as well as the next-to-leading two-loop order. For larger-than-physical charges, we consequently expect no appreciable volume corrections beyond leading-order QED.
description: 16 pages, 10 figures, v2 calculations corrected and conclusions updated
Conformal field theories dual to quantum gravity with strongly coupled matter
Creators: name: Apolo, Luis
name: Belin, Alexandre
name: Bintanja, Suzanne
name: Castro, Alejandra
name: Keller, Christoph A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: A holographic conformal field theory is dual to semi-classical general relativity in Anti-de Sitter space coupled to matter fields. If the CFT factorizes in the large-$N$ limit, then all couplings in its dual are suppressed by the Planck scale, making the matter fields weakly interacting. We propose a mechanism to produce CFTs whose dual matter fields couple weakly to gravity, but interact strongly with each other. We achieve this by turning on exactly marginal multi-trace deformations, and quantify the effect using conformal perturbation theory.
description: 5 pages, v3: minor changes, version as published in Phys. Rev. D
Robust control and optimal Rydberg states for neutral atom two-qubit gates
Creators: name: Mohan, Madhav
name: de Keijzer, Robert
name: Kokkelmans, Servaas
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We investigate the robustness of two-qubit gates to deviations of experimental controls, on a neutral atom platform utilizing Rydberg states. We construct robust CZ gates - employing techniques from quantum optimal control - that retain high Bell state fidelity $F > 0.999$ in the presence of significant deviations of the coupling strength to the Rydberg state. Such deviations can arise from laser intensity noise and atomic motion in an inhomogeneous coupling field. We also discuss methods to mitigate errors due to deviations of the laser detuning. The designed pulses operate on timescales that are short compared to the fundamental decay timescale set by spontaneous emission and blackbody radiation. We account for the finite lifetime of the Rydberg state in both the optimisation and fidelity calculations - this makes the gates conducive to noisy intermediate-scale quantum experiments, meaning that our protocols can reduce infidelity on near-term quantum computing devices. We calculate physical properties associated with infidelity for strontium-88 atoms - including lifetimes, polarisabilities and blockade strengths - and use these calculations to identify optimal Rydberg states for our protocols, which allows for further minimisation of infidelity.
description: 12 pages, 11 figures (v2): Added new Appendix to discuss additional sources of infidelity that can be neglected. New robust pulse designed for protocol B - the difference from the protocol B of (v1) is the added constraint that Rabi frequency does not tend to zero at any point in the pulse duration. Minor changes concerning figure formatting
Numerical linked cluster expansions for quantum quenches in one dimensional lattices
Creators: name: Mallayya, Krishnanand
name: Rigol, Marcos
Publisher: name: arXiv
Year: 2017
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: We discuss the application of numerical linked cluster expansions (NLCEs) to study one dimensional lattice systems in thermal equilibrium and after quantum quenches from thermal equilibrium states. For the former, we calculate observables in the grand canonical ensemble, and for the latter we calculate observables in the diagonal ensemble. When converged, NLCEs provide results in the thermodynamic limit. We use two different NLCEs - a maximally connected expansion introduced in previous works and a site-based expansion. We compare the effectiveness of both NLCEs. The site-based NLCE is found to work best for systems in thermal equilibrium. However, in thermal equilibrium and after quantum quenches, the site-based NLCE can diverge when the maximally connected one converges. We relate this divergence to the exponentially large number of clusters in the site-based NLCE and the behavior of the weights of observables in those clusters. We discuss the effectiveness of resummations to cure the divergence. Our NLCE calculations are compared to exact diagonalization ones in lattices with periodic boundary conditions. NLCEs are found to outperform exact diagonalization in periodic systems for all quantities studied.
description: 12 pages, 13 figures, published version
Classification of the Gait Pattern in Polymyalgia Rheumatica Patients Using Recurrent Neural Networks
Creators: name: Bawa, Anthony
name: Banitsas, Konstantinos
name: Abbod, Maysam
name: Van Gils, Mark
name: Moreno-Sanchez, Pedro A.
Publisher: name: Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
Year: 2023
Subjects: Gait
classification
pattern
optimizer
muscle

description: The early detection of movement disorders is essential for clinicians in many diseases, and it forms an integral part of effective treatment planning for patients. Polymyalgia rheumatica (PMR) is an autoimmune musculoskeletal disease that affects muscles around the pelvic girdle and shoulder blade. It is currently unknown how the strained hip muscles around the pelvic girdle create mobility limitations in patients. This study presents an algorithm for the classification of the hip muscle activation pattern in clinical gait analysis using recurrent neural networks (RNNs). RNNs was chosen because of its ability to capture temporal dependencies and process sequential electromyography (EMG) data in gait classification. A clinical gait assessment was conducted at KATH hospital which collected 250 gait segments from 18 PMR patients and 7 healthy control subjects. EMG signals were recorded from the vastus lateralis (VL), rectus femoris (RF), biceps femoris (BF), and semitendinosus (SE). Different optimizers were used in the RNN model to classify the hip muscle activation of the two groups to discriminate the gait pattern. Four optimizers (Adamax, Adagrad, SGD, and RMSprop) were used to evaluate the best optimizer for the RNN model. The accuracy results recorded from a cross-validation were, Adamax = 89%, Adagrad = 83%, SGD = 85%, and RMSprop = 78%. Adamax was the best performing optimizer while RMSprop was the least performing in the gait classification. An average accuracy of 84% from the four optimizers was sufficient to distinguish the gait pattern of the two groups. The findings of this study are useful in discriminating gait patterns based on hip muscle activation. This will provide essential information for the early detection of gait impairments by clinicians to make more informed and timely decisions.
Unified Gas-kinetic Scheme with Multigrid Convergence for Rarefied Flow Study
Creators: name: Zhu, Yajun
name: Zhong, Chengwen
name: Xu, Kun
Publisher: name: arXiv
Year: 2017
Subjects: subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: The unified gas kinetic scheme (UGKS) is a direct modeling method based on the gas dynamical model on the mesh size and time step scales. With the implementation of particle transport and collision in a time-dependent flux function, the UGKS can recover multiple flow physics from the kinetic particle transport to the hydrodynamic wave propagation. In comparison with direct simulation Monte Carlo (DSMC), the equations-based UGKS can use the implicit techniques in the updates of macroscopic conservative variables and microscopic distribution function. The implicit UGKS significantly increases the convergence speed for steady flow computations, especially in the highly rarefied and near continuum regime. In order to further improve the computational efficiency, for the first time a geometric multigrid technique is introduced into the implicit UGKS, where the prediction step for the equilibrium state and the evolution step for the distribution function are both treated with multigrid acceleration. The multigrid implicit UGKS (MIUGKS) is used in the non-equilibrium flow study, which includes microflow, such as lid-driven cavity flow and the flow passing through a finite-length flat plate, and high speed one, such as supersonic flow over a square cylinder. The MIUGKS shows 5 to 9 times efficiency increase over the previous implicit scheme. For the low speed microflow, the efficiency of MIUGKS is several orders of magnitude higher than the DSMC. Even for the hypersonic flow at Mach number 5 and Knudsen number 0.1, the MIUGKS is still more than 100 times faster than the DSMC method for a convergent steady state solution.
Manufacturing of microcavities by milling for X-ray identification of orthopedic implants
Creators: name: Denkena, Berend
name: Wichmann, Marcel
name: Eggers, Max-Enno
name: Hurschler, Christof
name: Ettinger, Max
name: Emonde, Crystal Kayaro
Publisher: name: Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
Year: 2023
Subjects: micro machining
burr
polymer
UHMWPE
implant
x-ray imaging
TKA

description: Due to its low X-ray attenuation, Ultra-high molecular weight polyethylene (UHMWPE) has limited visibility in radiographic images, making it difficult to monitor in-vivo. In this paper, a method is represented to address this limitation by integrating radiopaque markers into UHMWPE implant components, facilitating their identification in radiographs. For this purpose, micro-cavities are inserted into UHMWPE blocks by micro-milling. Due to the increasing individualisation of implants, a manufacturing process that is adaptable was selected for this purpose. If the idea of a patient- specific implant that is manufactured in the shortest possible time is taken as a starting point, the milling process provides promising opportunities. The entire production of the implant and the insertion of the microstructures is possible in a cost- and time-efficient form on a single machine. The primary challenge encountered was the formation burrs during the machining process. Milling tools with a diameter between 0.4 mm and 0.8 mm were investigated under variation of the process parameters spindle speed, feed rate and depth of cut. Based on the appearance and height of the burr, suitable parameters were found and links between burr-free cavities and process parameters were identified. The machined cavities were subsequently filled with a radiopaque composite material comprising of high density polyethylene (HDPE) and (10, 20, 30 wt. %) BaSO4 using a pellet extruder. By employing various analogue components, this method demonstrated improved visibility of individual structures and patterns in X-ray images.
System Simulations of Piezoelectric Energy Harvesters with the Finite Element Method
Creators: name: Hegendörfer, Andreas
Publisher: name: Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
Year: 2024

description: Piezoelectric energy harvesters (PEHs) consist of an electromechanical structure and an electric circuit, influencing each other. The piezoelectric effect, used as the energy conversion principle, describes the generation of electric voltage when the piezoelectric material is mechanically deformed and vice versa. The finite element method (FEM) offers powerful structural simulation capabilities, and the complete set of 3D piezoelectric equations can be solved without restrictions. Arbitrarily shaped and nonlinear electromechanical structures can be considered but accounting for electric circuits in the FEM is difficult. Firstly, a method for the coupling of nonlinear FEM simulations of the electromechanical structure to nonlinear electric circuits is introduced. In the FEM simulations the influence of the electric circuit on the electromechanical structure is considered via the boundary conditions. Subsequently, the practical applicability of the FEM-based simulation method is demonstrated and an electrically and mechanically nonlinear PEH with advanced electric circuits is investigated. However, the behavior of nonlinear circuit components and complicated electric circuits can only be approximated. An electronic circuit simulator (ECS) can be applied for accurate simulations of arbitrary electric circuits. A novel implicit FEM-ECS coupling method is proposed, which does not introduce any limitations and maintains the advantages of FEM and ECS to consider arbitrary PEHs. The Newton-Raphson method is applied to achieve rapid convergence at the interface between the FEM and ECS simulations resulting in computational efficient system simulations. Finally, the numerical optimization of the harvested energy of a mechanically and electrically nonlinear and nonideal PEH is addressed, accounting for a nonlinear stress constraint. In the optimization problem, a bimorph electromechanical structure equipped with different electric circuits is considered and electrical and mechanical design variables are introduced. Applying the FEM-ECS coupling, deep neural network (DNN) training data are generated, allowing for a computationally efficient evaluation of the objective function. A genetic algorithm using the DNNs is used to find the set of design variables that optimize the harvested energy, which is obtained at the maximum possible mechanical stresses.
Epitaxy and Structural Properties of (V,Bi,Sb)$_2$Te$_3$ Layers Exhibiting the Quantum Anomalous Hall Effect
Creators: name: Winnerlein, M.
name: Schreyeck, S.
name: Grauer, S.
name: Rosenberger, S.
name: Fijalkowski, K. M.
name: Gould, C.
name: Brunner, K.
name: Molenkamp, L. W.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The influence of Sb content, substrate type and cap layers on the quantum anomalous Hall effect observed in V-doped (Bi,Sb)$_2$Te$_3$ magnetic topological insulators is investigated. Thin layers showing excellent quantization are reproducibly deposited by molecular beam epitaxy at growth conditions effecting a compromise between controlled layer properties and high crystalline quality. The Sb content can be reliably determined from the in-plane lattice constant measured by X-ray diffraction, even in thin layers. This is the main layer parameter to be optimized in order to approach charge neutrality. Within a narrow range at about 80% Sb content, the Hall resistivity shows a maximum of about 10 k$Ω$ at 4 K and quantizes at mK temperatures. Under these conditions, thin layers grown on Si(111) or InP(111) and with or without a Te cap exhibit quantization. The quantization persists independently of the interfaces between cap, layer and substrate, the limited crystalline quality, and the degradation of the layer proving the robustness of the quantum anomalous Hall effect.
Induced interactions in the BCS-BEC crossover of two-dimensional Fermi gases with Rashba spin-orbit coupling
Creators: name: Lee, Juhee
name: Kim, Dong-Hee
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We investigate the Gorkov--Melik-Barkhudarov (GM) correction to superfluid transition temperature in two-dimensional Fermi gases with Rashba spin-orbit coupling (SOC) across the SOC-driven BCS-BEC crossover. In the calculation of the induced interaction, we find that the spin-component mixing due to SOC can induce both of the conventional screening and additional antiscreening contributions that interplay significantly in the strong SOC regime. While the GM correction generally lowers the estimate of transition temperature, it turns out that at a fixed weak interaction, the correction effect exhibits a crossover behavior where the ratio between the estimates without and with the correction first decreases with SOC and then becomes insensitive to SOC when it goes into the strong SOC regime. We demonstrate the applicability of the GM correction by comparing the zero-temperature condensate fraction with the recent quantum Monte Carlo results.
The hydration of calcium aluminate cement in mixtures with calcite: Investigations at different temperatures and CA2/CA ratios
Creators: name: Goergens, Julian Wenzel
Publisher: name: Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
Year: 2024
Subjects: Calcium Aluminate Cement, CAC, CA, CA2, Calcite, Limestone, Hydration, XRD, Hydrate phases, Conversion, CAH10, C2AHx, C3AH6, AH3, monocarbonate

description: This thesis represents a further step towards understanding the containment of the phenomenon of "hydrate phase conversion", which is considered to be the main challenge in the use of calcium aluminate cements (CAC) today. In this thesis, two main variables and their influence on the nature and quantity of all crystalline phases in hydrated CAC were investigated: The influence of hydration temperature was investigated with respect to the early hydration (0 - 48 h) and the late hydration (2 - 365 d). The effect of varying clinker composition, i.e. varying CA2/CA ratios in the CAC was investigated as a second variable. CAC reacts without chemical participation of the calcium carbonate (calcite) at 10°C, since the precursor phases C2AHx, which are conditional for the massive precipitation of carbonate-AFm phases, do not precipitate. At this temperature, CAH10 is the by far most dominant hydrate, without a sign of conversion for up to one year. At 23°C, CAH10 together with C2AHx, at 40°C and 60°C only C2AHx are formed. At all temperatures at which C2AHx is precipitated first, it is converted into monocarbonate within hours to minutes, and this process is accelerated with increasing temperature. Thus, after the main reaction, monocarbonate is always (except at 10°C) the dominant hydrate phase besides AH3. CAH10 does not reveal a "precursor function" for monocarbonate, it remains at 23°C until several weeks after hydration. At 10°C, CAH10 is still the predominant and, in the presence of amorphous AH3, the stable hydrate phase even after one year. C3AH6, which at later hydration times is quantified at 60°C, is causally dependent on the amount of evaporated mixing water in the early hydration. Thus, a reduced w/CAC ratio due to evaporation appears to determine the ratio of monocarbonate to C3AH6 rather than a thermal stability limit of monocarbonate. C3AH6 partially converts to monocarbonate in carbonate-bearing solution. On the other hand, if the CA2/CA ratio in the clinker of the CAC is varied, the amount of quantifiable AH3 changes in direct proportion to this ratio. However, the quantity of AH3 is not directly proportional to the strength, nor is the degree of hydration or the absolute amount of CA but specific populations of macro-porosity. It is much likely that the paste viscosity while stirring plays the decisive role in the formation of different degrees of macro-porosity. With a novel combination of three methodologies, it is now possible to exactly determine which porosity sizes are responsible for the fracture failure of individual samples of CAC-Cc-mixes.
A hybridizable discontinuous Galerkin method with characteristic variables for Helmholtz problems
Creators: name: Modave, A.
name: Chaumont-Frelet, T.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Numerical Analysis (math.NA)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: A new hybridizable discontinuous Galerkin method, named the CHDG method, is proposed for solving time-harmonic scalar wave propagation problems. This method relies on a standard discontinuous Galerkin scheme with upwind numerical fluxes and high-order polynomial bases. Auxiliary unknowns corresponding to characteristic variables are defined at the interface between the elements, and the physical fields are eliminated to obtain a reduced system. The reduced system can be written as a fixed-point problem that can be solved with stationary iterative schemes. Numerical results with 2D benchmarks are presented to study the performance of the approach. Compared to the standard HDG approach, the properties of the reduced system are improved with CHDG, which is more suited for iterative solution procedures. The condition number of the reduced system is smaller with CHDG than with the standard HDG method. Iterative solution procedures with CGNR or GMRES required smaller numbers of iterations with CHDG.