cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Instability in large bounded domains -- branched versus unbranched resonances
Creators: name: Avery, Montie
name: Dedina, Cedric
name: Smith, Aislinn
name: Scheel, Arnd
Publisher: name: arXiv
Year: 2020
Subjects: subject: Pattern Formation and Solitons (nlin.PS)
subject: Dynamical Systems (math.DS)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We study transitions from convective to absolute instability near a trivial state in large bounded domains for prototypical model problems in the presence of transport and negative nonlinear feedback. We identify two generic scenarios, depending on the nature of the linear mechanism for instability, which both lead to different, universal bifurcation diagrams. In the first, classical case of a linear branched resonance the transition is hard, that is, small changes in a control parameter lead to a finite-size state. In the second, novel case of an unbranched resonance, the transition is gradual. In both cases, the bifurcation diagram is determined by interaction of the leading edge of an invasion front with upstream boundary conditions. Technically, we analyze this interaction in a heteroclinic gluing bifurcation analysis that uses geometric desingularization of the trivial state.
description: 17 pages, 9 figures
Development and validation of a numerical wave tank based on the Harmonic Polynomial Cell and Immersed Boundary methods to model nonlinear wave-structure interaction
Creators: name: Robaux, Fabien
name: Benoit, Michel
Publisher: name: arXiv
Year: 2020
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: A fully nonlinear potential Numerical Wave Tank (NWT) is developed in two dimensions, using a combination of the Harmonic Polynomial Cell (HPC) method for solving the Laplace problem on the wave potential and the Immersed Boundary Method (IBM) for capturing the free surface motion. This NWT can consider fixed, submerged or wall-sided surface piercing, bodies. To compute the flow around the body and associated pressure field, a novel multi overlapping grid method is implemented. Each grid having its own free surface, a two-way communication is ensured between the problem in the body vicinity and the larger scale wave propagation problem. Pressure field and nonlinear loads on the structure are computed by solving a boundary value problem on the time derivative of the potential. The stability and convergence properties of the solver are studied basing on extensive tests with standing waves of large to extreme wave steepness, up to $H/λ=0.2$ ($H$ is the crest-to-trough wave height and $λ$ the wavelength). Ranges of optimal time and spatial discretizations are determined and high-order convergence properties are verified, first without using any filter. For cases with either high level of nonlinearity or long simulation duration, the use of mild Savitzky-Golay filters is shown to extend the range of applicability of the model. Then, the NWT is tested against two wave flume experiments, analyzing forces on bodies in various wave conditions. First, nonlinear components of the vertical force acting on a small horizontal circular cylinder with low submergence below the mean water level are shown to be accurately simulated up to the third order in wave steepness. The second case is a dedicated experiment with a floating barge of rectangular cross-section. This very challenging case (body with sharp corners in large waves) allows to examine the behavior (...to continue...)
description: 47 pages, 26 figures
R&D programmes oriented towards specific future facilities
Creators: name: Michizono, S.
name: Nakada, T.
name: Stapnes, S.
Publisher: name: CERN Yellow Reports: Monographs
Year: 2022

description: The International Linear Collider (ILC) is an electron-positron collider with a collision energy of 250 GeV (total length of approximately 20 km). The design study for the ILC for a collision energy of 500 GeV started in 2004, and the technical design report (TDR) was published by the Global Design Effort (GDE) international team in 2013. More than 2 400 researchers have contributed to the TDR. After publication, R&D activities regarding linear colliders were organised by the Linear Collider Collaboration (LCC). The 250 GeV ILC for a Higgs factory was proposed and published as the ILC Machine Staging Report 2017. The International Development Team (IDT) was established by the International Committee for Future Accelerators (ICFA) in August 2020 to prepare to establish the ILC preparatory laboratory (Pre-lab) as the first step towards the construction of the ILC in Japan. The principal accelerator activities of the ILC Pre-lab are technical preparations and engineering design and documentation, and the former is summarised in “Technical Preparation and Work Packages (WPs) during ILC Pre-lab”. The ILC Pre-lab activities are expected to continue for approximately four years, and the ILC accelerator construction will require nine years.
description: CERN Yellow Reports: Monographs, Vol. 1 (2022): European Strategy for Particle Physics - Accelerator R&D Roadmap
Interplay between parallel and diagonal electronic nematic phases in interacting systems
Creators: name: Doh, Hyeonjin
name: Friedman, Nir
name: Kee, Hae-Young
Publisher: name: arXiv
Year: 2006
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: An electronic nematic phase can be classified by a spontaneously broken discrete rotational symmetry of a host lattice. In a square lattice, there are two distinct nematic phases. The parallel nematic phase breaks $x$ and $y$ symmetry, while the diagonal nematic phase breaks the diagonal $(x+y)$ and anti-diagonal $(x-y)$ symmetry. We investigate the interplay between the parallel and diagonal nematic orders using mean field theory. We found that the nematic phases compete with each other, while they coexist in a finite window of parameter space. The quantum critical point between the diagonal nematic and isotropic phases exists, and its location in a phase diagram depends on the topology of the Fermi surface. We discuss the implication of our results in the context of neutron scattering and Raman spectroscopy measurements on La$_{2-x}$Sr$_x$CuO$_4$.
description: 8 pages, 10 figures
Nonsplitting in Kirchberg's ideal-related KK-theory
Creators: name: Eilers, Soren
name: Restorff, Gunnar
name: Ruiz, Efren
Publisher: name: arXiv
Year: 2008
Subjects: subject: Operator Algebras (math.OA)
subject: FOS: Mathematics
subject: 46L35

description: A universal coefficient theorem in the setting of Kirchberg's ideal-related KK-theory was obtained in the fundamental case of a C*-algebra with one specified ideal by Bonkat and proved there to split, unnaturally, under certain conditions. Employing certain K-theoretical information derivable from the given operator algebras in a way introduced here, we shall demonstrate that Bonkat's UCT does not split in general. Related methods lead to information on the complexity of the K-theory which must be used to classify *-isomorphisms for purely infinite C*-algebras with one non-trivial ideal.
description: 14 pages, minor typos fixed, 5 figures added
Calculating the linear critical gradient for the ion-temperature-gradient mode in magnetically confined plasmas
Creators: name: Roberg-Clark, G. T.
name: Plunk, G. G.
name: Xanthopoulos, P.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: A first-principles method to calculate the critical temperature gradient for the onset of the ion-temperature-gradient mode (ITG) in linear gyrokinetics is presented. We find that conventional notions of the connection length previously invoked in tokamak research should be revised and replaced by a generalized correlation length to explain this onset in stellarators. Simple numerical experiments and gyrokinetic theory show that localized "spikes" in shear, a hallmark of stellarator geometry, are generally insufficient to constrain the parallel correlation length of the mode. ITG modes that localize within bad drift curvature wells that have a critical gradient set by peak drift curvature are also observed. A case study of nearly helical stellarators of increasing field period demonstrates that the critical gradient can indeed be controlled by manipulating magnetic geometry, but underscores the need for a general framework to evaluate the critical gradient. We conclude that average curvature and global shear set the correlation length of resonant ITG modes near the absolute critical gradient, the physics of which is included through direct solution of the gyrokinetic equation. Our method, which handles general geometry and is more efficient than conventional gyrokinetic solvers, could be applied to future studies of stellarator ITG turbulence optimization.
description: 22 pages, 6 figures. Accepted for publication in The Journal of Plasma Physics (JPP)
Melting of Colloidal Molecular Crystals on Triangular Lattices
Creators: name: Sarlah, A.
name: Franosch, T.
name: Frey, E.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: The phase behavior of a two-dimensional colloidal system subject to a commensurate triangular potential is investigated. We consider the integer number of colloids in each potential minimum as rigid composite objects with effective discrete degrees of freedom. It is shown that there is a rich variety of phases including ``herring bone'' and ``Japanese 6 in 1'' phases. The ensuing phase diagram and phase transitions are analyzed analytically within variational mean-field theory and supplemented by Monte Carlo simulations. Consequences for experiments are discussed.
description: 10 pages, 4 figures
On Convergence of Incremental Gradient for Non-convex Smooth Functions
Creators: name: Koloskova, Anastasia
name: Doikov, Nikita
name: Stich, Sebastian
name: Jaggi, Martin
Publisher: name: CISPA
Year: 2024

description: In machine learning and neural network optimization, algorithms like incremental gradient, single shuffle SGD, and random reshuffle SGD are popular due to their cache-mismatch efficiency and good practical convergence behavior. However, their optimization properties in theory, especially for non-convex smooth functions, remain incompletely explored. This paper delves into the convergence properties of SGD algorithms with arbitrary data ordering, within a broad framework for non-convex smooth functions. Our findings show enhanced convergence guarantees for incremental gradient and single shuffle SGD. Particularly if n
 is the training set size, we improve n
 times the optimization term of convergence guarantee to reach accuracy ϵ
 from O(nϵ)
 to O(1ϵ).
Playing to distraction: towards a robust training of CNN classifiers through visual explanation techniques
Creators: name: Morales, David
name: Talavera, Estefania
name: Remeseiro, Beatriz
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: The field of deep learning is evolving in different directions, with still the need for more efficient training strategies. In this work, we present a novel and robust training scheme that integrates visual explanation techniques in the learning process. Unlike the attention mechanisms that focus on the relevant parts of images, we aim to improve the robustness of the model by making it pay attention to other regions as well. Broadly speaking, the idea is to distract the classifier in the learning process to force it to focus not only on relevant regions but also on those that, a priori, are not so informative for the discrimination of the class. We tested the proposed approach by embedding it into the learning process of a convolutional neural network for the analysis and classification of two well-known datasets, namely Stanford cars and FGVC-Aircraft. Furthermore, we evaluated our model on a real-case scenario for the classification of egocentric images, allowing us to obtain relevant information about peoples' lifestyles. In particular, we work on the challenging EgoFoodPlaces dataset, achieving state-of-the-art results with a lower level of complexity. The obtained results indicate the suitability of our proposed training scheme for image classification, improving the robustness of the final model.
description: 20 pages,3 figures, 4 tables
MODELING ANIMAL AND FORAGE RESPONSE TO FERTILIZATION OF ANNUAL RANGELANDS
Creators: name: Olson, Kent D.
name: Mikesell, Chris L.
name: Raguse, Charles A.
name: George, Melvin R.
name: Taggard, Ken L.
name: Olson, Kent D.
name: Mikesell, Chris L.
name: Raguse, Charles A.
name: George, Melvin R.
name: Taggard, Ken L.
Publisher: name: Unknown
Year: 1988
Subjects: Livestock Production/Industries

description: The response functions for forage, animal gain, and stocking rate were estimated from data obtained in a three-year fertilization experiment on California annual range. Degree-days; the interactions between degree-days and nitrogen, between degree-days and phosphorus-sulphur, and between nitrogen and phosphorus-sulphur; and the lagged forage variable were significant in explaining the variations in forage growth, animal gain, and stocking rate. The impact of PS was more important in interaction with DD or N than by itself. The correct impact of moisture was not found due to misspecification of the variable in the model. The models for the first year and the three years combined were well behaved; however, the models for the last two years combined neither explained adequately nor behaved well.
Solar-like oscillations in alpha Centauri B
Creators: name: Kjeldsen, Hans
name: Bedding, Timothy R.
name: Butler, R. Paul
name: Christensen-Dalsgaard, Joergen
name: Kiss, Laszlo L.
name: McCarthy, Chris
name: Marcy, Geoffrey W.
name: Tinney, Christopher G.
name: Wright, Jason T.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We have made velocity observations of the star alpha Cen B from two sites, allowing us to identify 37 oscillation modes with l=0-3. Fitting to these modes gives the large and small frequency separations as a function of frequency. The mode lifetime, as measured from the scatter of the oscillation frequencies about a smooth trend, is similar to that in the Sun. Limited observations of the star delta Pav show oscillations centred at 2.3 mHz with peak amplitudes close to solar. We introduce a new method of measuring oscillation amplitudes from heavily-smoothed power density spectra, from which we estimated amplitudes for alpha Cen A and B, beta Hyi, delta Pav and the Sun. We point out that the oscillation amplitudes may depend on which spectral lines are used for the velocity measurements.
description: accepted for publication in ApJ
Exeler, Adolf / Scherer, Georg (Hrsg.), Glaubensinformation
Creators: name: Motel, Hans-Beat
Publisher: name: Ökumenische Rundschau
Year: 2025

description: Ökumenische Rundschau, Bd. 21 Nr. 3 (1972): Ökumenische Rundschau, Band 21, Heft 3
Correction: Taking action to advance the study of race and ethnicity: the Women’s Health Initiative (WHI)
Creators: name: Paskett, Electra D.
name: Kooperberg, Charles
name: Cené, Crystal Wiley
name: Aragaki, Aaron
name: Breathett, Khadijah
name: Follis, Shawna
name: Masaki, Kamal
name: Stefanick, Marcia L.
name: Jimenez, Monik
name: Thomson, Cynthia A.
name: Garcia, Lorena
name: Pettinger, Mary
name: Dilworth-Anderson, Peggye
Publisher: name: Springer Nature
Year: 2022

description:
Correction to "Taking action to advance the study of race and ethnicity: the Women’s Health Initiative (WHI)"
Dependence of spontaneous emission rates of emitters on the refractive index of the surrounding medial
Creators: name: Duan, Chang-Kui
name: Reid, Michael F.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: For emitters in a medium, different macroscopic or microscopic theoretical models predict substantially different dependencies of the spontaneous emission lifetime on refractive index. Various measurements have been carried out on Eu$^{3+}$, Ce$^{3+}$ and Nd$^{3+}$ ions, and quantum dots in different surrounding medial. The dependence of the spontaneous emission rates on refractive index has been interpreted with different models. By closely examining some of the experimental results, we notice that some interpretations are based on implicit assumptions which are hard to justify, and some measurements contain too big uncertainties to discriminate among different models. In this work we reanalyse the avilable measured results and give a consistent interpretation.
description: 9 pages, 2 figures, to be presented on RERC2005, Keystone Colorado, Jun 26-30 2005
Prospects for detection and application of the alignment of galaxies with the large-scale velocity field
Creators: name: van Gemeren, Iris R.
name: Chisari, Nora Elisa
Publisher: name: arXiv
Year: 2020
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Studies of intrinsic alignment effects mostly focus on the correlations between shapes of galaxies with each other, or with the underlying density field of the large scale structure of the universe. Lately, the correlation between shapes of galaxies and the large-scale velocity field has been proposed as an additional probe of the large scale structure. We use a Fisher forecast to make a prediction for the detectability of this velocity-shape correlation with a combination of redshifts and shapes from the 4MOST+LSST surveys, and radial velocity reconstruction from the Simons Observatory. The signal-to-noise ratio for the velocity-shape (dipole) correlation is 7.4, relative to 44 for the galaxy density-shape (monopole) correlation and for a maximum wavenumber of $0.2\: \mathrm{Mpc^{-1}}$. Encouraged by these predictions, we discuss two possible applications for the velocity-shape correlation. Measuring the velocity-shape correlation could improve the mitigation of selection effects induced by intrinsic alignments on galaxy clustering. We also find that velocity-shape measurements could potentially aid in determining the scale-dependence of intrinsic alignments when multiple shape measurements of the same galaxies are provided.
description: 7 pages, 2 tables, 2 figures, S/N correction
COMMON PROPERTY RESOURCES IN A GLOBAL CONTEXT
Creators: name: Runge, C. Ford
name: Runge, C. Ford
Publisher: name: Unknown
Year: 1990
Subjects: Resource /Energy Economics and Policy

description: The "global commons" is a metaphor. Metaphorically, all of the earth's resources are held in common by this and future generations, to be used and abused as we and our heirs see fit. Yet "the commons" metaphor may also be seen at a less global level, and less metaphorically. In much of the developing world, common property provides a complex system of norms and conventions regulating individual use rights to a variety of natural resources, including forests, grazing lands, fisheries and water resources. This article will examine both macro-level issues of the commons, and micro-level cases, with emphasis on developing countries. Macro-level issues involve problems of international governance, while micro cases involve local management of natural and human resources. While much previous attention has been given to international governance, such as the Law of the Sea Treaty, or the Montreal Protocol on chlorofluorocarbon emissions, this article will also give particular attention to local resource management.
R&D programmes oriented towards specific future facilities
Creators: name: Benedikt, M.
name: Blondel, A.
name: Brunner, O.
name: Janot, P.
name: Jensen, E.
name: Koratzinos, M.
name: Losito, R.
name: Oide, K.
name: Raubenheimer, T.
name: Zimmermann, F.
Publisher: name: CERN Yellow Reports: Monographs
Year: 2022

description: In summer 2021, the Future Circular Collider Feasibility Study was launched. The FCC-ee builds on 60 years of operating colliding beam storage rings. The design is robust and will provide high luminosity over the desired centre-of-mass energy range from 90 to 365 GeV. The FCC-ee is also the most sustainable of all Higgs and electroweak factory proposals, in that it implies the lowest energy consumption for a given value of total integrated luminosity. In the following we present more details, describe additional R&D elements, and identify links and overlaps with the Accelerator R&D roadmap.
description: CERN Yellow Reports: Monographs, Vol. 1 (2022): European Strategy for Particle Physics - Accelerator R&D Roadmap
Causal influence in operational probabilistic theories
Creators: name: Perinotti, Paolo
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study the relation of causal influence between input systems of a reversible evolution and its output systems, in the context of operational probabilistic theories. We analyse two different definitions that are borrowed from the literature on quantum theory -- where they are equivalent. One is the notion based on signalling, and the other one is the notion used to define the neighbourhood of a cell in a quantum cellular automaton. The latter definition, that we adopt in the general scenario, turns out to be strictly weaker than the former: it is possible for a system to have causal influence on another one without signalling to it. Remarkably, the counterexample comes from classical theory, where the proposed notion of causal influence determines a redefinition of the neighbourhood of a cell in cellular automata. We stress that, according to our definition, it is impossible anyway to have causal influence in the absence of an interaction, e.g.~in a Bell-like scenario. We study various conditions for causal influence, and introduce the feature that we call no interaction without disturbance, under which we prove that signalling and causal influence coincide. The proposed definition has interesting consequences on the analysis of causal networks, and leads to a revision of the notion of neighbourhood for classical cellular automata, clarifying a puzzle regarding their quantisation that apparently makes the neighbourhood larger than the original one.
description: 13 pages, no figures, many diagrams. Accepted for publication on "Quantum"
The X-ray Structure of the Pulsar Bow Shock G189.22+2.90 in the Supernova Remnant IC 443
Creators: name: Gaensler, B. M.
name: Chatterjee, S.
name: Slane, P. O.
name: van der Swaluw, E.
name: Camilo, F.
name: Hughes, J. P.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present a deep observation with the Chandra X-ray Observatory of the neutron star bow shock G189.22+2.90 in the supernova remnant (SNR) IC 443. Our data confirm the cometary morphology and central point source seen previously, but also reveal considerable new structure. Specifically, we find that the X-ray nebula consists of two distinct components: a "tongue" of bright emission close to the neutron star, enveloped by a larger, fainter "tail". We interpret the tongue and tail as delineating the termination shock and the post-shock flow, respectively, as previously identified also in the pulsar bow shock G359.23-0.82 ("the Mouse"). However, for G189.22+2.90 the tongue is much less elongated than for the Mouse, while the tail is much broader. These differences are consistent with the low Mach number, M >~ 2, expected for a neutron star moving through the hot gas in a SNR's interior, supporting the case for a physical association between G189.22+2.90 and IC 443. We resolve the stand-off distance between the star and the head of the bow shock, which allows us to estimate a space velocity for the neutron star of ~230 km/s, independent of distance. We detect thermal emission from the neutron star surface at a temperature of 102 +/- 22 eV, which is consistent with the age of SNR IC 443 for standard neutron star cooling models. We also identify two compact knots of hard emission located 1-2 arcsec north and south of the neutron star.
description: 8 pages, including 3 color EPS figure. Expaneded to include new figures, plus discussion of the association between the pulsar and the supernova remnant. ApJ, in press
Surface Self-Assembly of Functionalized Molecules on Ag(111): More Than Just Chemical Intuition
Creators: name: Jeindl, Andreas
name: Domke, Jari
name: Hörmann, Lukas
name: Sojka, Falko
name: Forker, Roman
name: Fritz, Torsten
name: Hofmann, Oliver T.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The fabrication of nanomaterials involves self-ordering processes of functional molecules on inorganic surfaces. To obtain specific molecular arrangements, a common strategy is to equip molecules with functional groups. However, focusing on the functional groups alone does not provide a comprehensive picture. Especially at interfaces, processes that govern self-ordering are complex and involve various physical and chemical effects, often leading to structures that defy chemical intuition, as we showcase here on the example of a homologous series of quinones on Ag(111). From chemical intuition one could expect that such quinones, which all bear the same functionalization, form similar motifs. In salient contrast, our joint theoretical and experimental study shows that profoundly different structures are formed. Using a machine-learning-based structure search algorithm, we find that this is due to a shift of the balance of three antagonizing driving forces: adsorbate-substrate interactions governing adsorption sites, adsorbate-adsorbate interactions favoring close packing, and steric hindrance inhibiting certain otherwise energetically beneficial molecular arrangements. The theoretical structures show excellent agreement with our experimental characterizations of the organic/inorganic interfaces, both for the unit cell sizes and the orientations of the molecules within. With a detailed examination of all driving forces, we are further able to devise a design principle for self-assembly of functionalized molecules. The non-intuitive interplay of similarly strong interaction mechanisms will continue to be a challenging aspect for the design of functional interfaces. Our agreement between theory and experiment combined with the new physical insights indicates that these methods have now reached the necessary accuracy to do so.
The binary fraction of the young cluster NGC 1818 in the Large Magellanic Cloud
Creators: name: Hu, Yi
name: Deng, Licai
name: deGrijs, Richard
name: Goodwin, Simon P.
name: Liu, Qiang
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We use high-resolution {\sl Hubble Space Telescope} imaging observations of the young ($\sim 15-25$ Myr-old) star cluster NGC 1818 in the Large Magellanic Cloud to derive an estimate for the binary fraction of F stars ($1.3 < M_\star/M_\odot < 1.6$). This study provides the strongest constraints yet on the binary fraction in a young star cluster in a low-metallicity environment (${[Fe/H]} \sim -0.4$ dex). Employing artificial-star tests, we develop a simple method that can efficiently measure the probabilities of stellar blends and superpositions from the observed stellar catalog. We create synthetic color-magnitude diagrams matching the fundamental parameters of NGC 1818, with different binary fractions and mass-ratio distributions. We find that this method is sensitive to binaries with mass ratios, $q \ga 0.4$. For binaries with F-star primaries and mass ratios $q > 0.4$, the binary fraction is $\sim 0.35$. This suggests a total binary fraction for F stars of 0.55 to unity, depending on assumptions about the form of the mass-ratio distribution at low $q$.
description: 30 pages, 9 figures
Spectral Preconditioning for Gradient Methods on Graded Non-convex Functions
Creators: name: Doikov, Nikita
name: Stich, Sebastian
name: Jaggi, Martin
Publisher: name: CISPA
Year: 2024

description: The performance of optimization methods is often tied to the spectrum of the objective Hessian. Yet, conventional assumptions, such as smoothness, do often not enable us to make finely-grained convergence statements -- particularly not for non-convex problems. Striving for a more intricate characterization of complexity, we introduce a unique concept termed graded non-convexity. This allows to partition the class of non-convex problems into a nested chain of subclasses. Interestingly, many traditional non-convex objectives, including partially convex problems, matrix factorizations, and neural networks, fall within these subclasses. As a second contribution, we propose gradient methods with spectral preconditioning, which employ inexact top eigenvectors of the Hessian to address the ill-conditioning of the problem, contingent on the grade. Our analysis reveals that these new methods provide provably superior convergence rates compared to basic gradient descent on applicable problem classes, particularly when large gaps exist between the top eigenvalues of the Hessian. Our theory is validated by numerical experiments executed on multiple practical machine learning problems.
Coding Schemes for Line Networks
Creators: name: Pakzad, Payam
name: Fragouli, Christina
name: Shokrollahi, Amin
Publisher: name: arXiv
Year: 2005
Subjects: subject: Information Theory (cs.IT)
subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: Networking and Internet Architecture (cs.NI)
subject: FOS: Computer and information sciences
subject: H.1.1

description: We consider a simple network, where a source and destination node are connected with a line of erasure channels. It is well known that in order to achieve the min-cut capacity, the intermediate nodes are required to process the information. We propose coding schemes for this setting, and discuss each scheme in terms of complexity, delay, achievable rate, memory requirement, and adaptability to unknown channel parameters. We also briefly discuss how these schemes can be extended to more general networks.
description: To appear in the proceedings of the 2005 IEEE international Symposium on Information Theory, Adelaide, Australia, Sept. 4-9, 2005
Geyer, Hans-Georg / Norbert, Hans / u.a., Theologie und Soziologie
Creators: name: Rendtorff, Trutz
Publisher: name: Ökumenische Rundschau
Year: 2025

description: Ökumenische Rundschau, Bd. 21 Nr. 3 (1972): Ökumenische Rundschau, Band 21, Heft 3
Algebraic geometry of Lie bialgebras defined by solutions of the classical Yang-Baxter equation
Creators: name: Abedin, Raschid
name: Burban, Igor
Publisher: name: arXiv
Year: 2020
Subjects: subject: Algebraic Geometry (math.AG)
subject: Quantum Algebra (math.QA)
subject: FOS: Mathematics

description: This paper is devoted to algebro-geometric study of infinite dimensional Lie bialgebras, which arise from solutions of the classical Yang-Baxter equation. We regard trigonometric solutions of this equation as twists of the standard Lie bialgebra cobracket on an appropriate affine Lie algebra and work out the corresponding theory of Manin triples, putting it into an algebro-geometric context. As a consequence of this approach, we prove that any trigonometric solution of the classical Yang-Baxter equation arises from an appropriate algebro-geometric datum. The developed theory is illustrated by some concrete examples.
Locally Adaptive Federated Learning
Creators: name: Mukherjee, Sohom
name: Loizou, Nicolas
name: Stich, Sebastian
Publisher: name: CISPA
Year: 2024

description: Federated learning is a paradigm of distributed machine learning in which multiple clients coordinate with a central server to learn a model, without sharing their own training data. Standard federated optimization methods such as Federated Averaging (FedAvg) ensure balance among the clients by using the same stepsize for local updates on all clients. However, this means that all clients need to respect the global geometry of the function which could yield slow convergence. In this work, we propose locally adaptive federated learning algorithms, that leverage the local geometric information for each client function. We show that such locally adaptive methods with uncoordinated stepsizes across all clients can be particularly efficient in interpolated (overparameterized) settings, and analyze their convergence in the presence of heterogeneous data for convex and strongly convex settings. We validate our theoretical claims by performing illustrative experiments for both i.i.d. non-i.i.d. cases. Our proposed algorithms match the optimization performance of tuned FedAvg in the convex setting, outperform FedAvg as well as state-of-the-art adaptive federated algorithms like FedAMS for non-convex experiments, and come with superior generalization performance.
БЕСПЛОДИЕ, АССОЦИИРОВАННОЕ С ЭНДОМЕТРИОЗОМ
Creators: name: Гафурова, Феруза
name: Тожибоева, Насиба
Publisher: name: Zenodo
Year: 2024

description: Статья посвящена исследованию влияния эндометриоза на фертильность у женщин с бесплодием. В исследовании участвовали 92 пациентки, разделённые на две группы в зависимости от стадии эндометриоза. Проанализированы репродуктивные исходы после лапароскопического лечения и применения экстракорпорального оплодотворения (ЭКО). Результаты показали, что пациентки с I–II стадией эндометриоза имеют высокие шансы на наступление беременности после лапароскопии, в то время как у женщин с III–IV стадией заболевания ЭКО оказалось более эффективным методом. Снижение овариального резерва наблюдалось у всех пациенток, однако оно было более выраженным у женщин с тяжёлыми формами заболевания. Выводы подчёркивают необходимость индивидуализированного подхода к лечению бесплодия у пациенток с эндометриозом, с учётом стадии заболевания и репродуктивных планов.
Numerical Simulation of Non-Abelian Particle-Field Dynamics
Creators: name: Dumitru, Adrian
name: Nara, Yasushi
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Numerical 1D-3V solutions of the Wong-Yang-Mills equations with anisotropic particle momentum distributions are presented. They confirm the existence of plasma instabilities for weak initial fields and their saturation at a level where the particle motion is affected, similar to Abelian plasmas. The isotropization of the particle momenta by strong random fields is shown explicitly, as well as their nearly exponential distribution up to a typical hard scale, which arises from scattering off field fluctuations. By variation of the lattice spacing we show that the effects described here are independent of the UV field modes near the end of the Brioullin zone.
description: 8 pages, 5 figures; to appear in the proceedings of the "Workshop on Quark-Gluon-Plasma Thermalization", August 10 -- 12, 2005, TU Wien, Austria; http://hep.itp.tuwien.ac.at/qgpth05
A global microscopic description of nucleon-nucleus scattering with quantified uncertainties
Creators: name: Whitehead, T. R.
name: Lim, Y.
name: Holt, J. W.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We develop for the first time a microscopic global nucleon-nucleus optical potential with quantified uncertainties suitable for analyzing nuclear reaction experiments at next-generation rare-isotope beam facilities. Within the improved local density approximation and without any adjustable parameters, we begin by computing proton-nucleus and neutron-nucleus optical potentials from a set of five nuclear forces from chiral effective field theory for 1800 target nuclei in the mass range 12 $\leq$ A $\leq$ 242 for energies between 0 MeV $
"Serpentine"/antigorite, chrysotile/"L.O. wanted to use it for superleaks for liquid He" SM/memo, "The Structure of chrysotile asbestos", 1953, July 13. A. Knopf to Onsager 1950, Nov. 4.
Creators: name: Onsager, Lars
Publisher: name: Unknown
Year: 0

description: Tidligere referanse: 13:183
Energy-recovery linacs
Creators: name: Klein, M.
name: Hutton, A.
name: Angal-Kalinin, D.
name: Aulenbacher, K.
name: Bogacz, A.
name: Hoffstaetter, G.
name: Jensen, E.
name: Kaabi, W.
name: Kayran, D.
name: Knobloch, J.
name: Kuske, B.
name: Marhauser, F.
name: Pietralla, N.
name: Tanaka, O.
name: Vaccarezza, C.
name: Vinokurov, N.
name: Williams, P.
name: Zimmermann, F.
Publisher: name: CERN Yellow Reports: Monographs
Year: 2022

description: Energy Recovery is at the threshold of becoming a key means for the advancement of accelerators. Recycling the kinetic energy of a used beam for accelerating a newly injected beam, i.e. reducing the power consumption, utilising the high injector brightness and dumping at injection energy: these are the key elements of a novel accelerator concept, invented half a century ago. The potential of this technique may be compared with the finest innovations of accelerator technology such as by Widerøe, Lawrence, Veksler, Kerst, van der Meer and others during the past century. Innovations of such depth are rare, and their impact is only approximately predictable. The panel notes with much interest that the ERL technology is close to high-current and high-energy application, requiring dedicated and coordinated R&D efforts, with the stunning potential to revolutionise particle, nuclear and applied physics, as well as key industry areas. This comes at a time where attention to sustainability is an overarching necessity for this planet, not least big science. ERLs are therefore primed for inclusion among the grand visions our field has been generating. Adequate support for the development, in Europe and worldwide, will allow this potential to be realised.
description: CERN Yellow Reports: Monographs, Vol. 1 (2022): European Strategy for Particle Physics - Accelerator R&D Roadmap
Evolutionary Diversity Optimization and the Minimum Spanning Tree Problem
Creators: name: Bossek, Jakob
name: Neumann, Frank
Publisher: name: arXiv
Year: 2020
Subjects: subject: Neural and Evolutionary Computing (cs.NE)
subject: FOS: Computer and information sciences

description: In the area of evolutionary computation the calculation of diverse sets of high-quality solutions to a given optimization problem has gained momentum in recent years under the term evolutionary diversity optimization. Theoretical insights into the working principles of baseline evolutionary algorithms for diversity optimization are still rare. In this paper we study the well-known Minimum Spanning Tree problem (MST) in the context of diversity optimization where population diversity is measured by the sum of pairwise edge overlaps. Theoretical results provide insights into the fitness landscape of the MST diversity optimization problem pointing out that even for a population of $μ=2$ fitness plateaus (of constant length) can be reached, but nevertheless diverse sets can be calculated in polynomial time. We supplement our theoretical results with a series of experiments for the unconstrained and constraint case where all solutions need to fulfill a minimal quality threshold. Our results show that a simple $(μ+1)$-EA can effectively compute a diversified population of spanning trees of high quality.
"S.C. Green's functions"/Singularities of Joyce's f.c.c. solution". Related to G.S. Joyce "Lattice Green function or the anisotropic fcc lattice" J. Phys. C. 1971, vol. 4, L53
Creators: name: Onsager, Lars
Publisher: name: Unknown
Year: 0

description: Tidligere referanse: 13:184
An Alternative Prior Process for Nonparametric Bayesian Clustering
Creators: name: Wallach, Hanna M.
name: Jensen, Shane T.
name: Dicker, Lee
name: Heller, Katherine A.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Methodology (stat.ME)
subject: Statistics Theory (math.ST)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: Prior distributions play a crucial role in Bayesian approaches to clustering. Two commonly-used prior distributions are the Dirichlet and Pitman-Yor processes. In this paper, we investigate the predictive probabilities that underlie these processes, and the implicit "rich-get-richer" characteristic of the resulting partitions. We explore an alternative prior for nonparametric Bayesian clustering -- the uniform process -- for applications where the "rich-get-richer" property is undesirable. We also explore the cost of this process: partitions are no longer exchangeable with respect to the ordering of variables. We present new asymptotic and simulation-based results for the clustering characteristics of the uniform process and compare these with known results for the Dirichlet and Pitman-Yor processes. We compare performance on a real document clustering task, demonstrating the practical advantage of the uniform process despite its lack of exchangeability over orderings.
Large Quantum Delocalization of a Levitated Nanoparticle using Optimal Control: Applications for Force Sensing and Entangling via Weak Forces
Creators: name: Weiss, T.
name: Roda-Llordes, M.
name: Torrontegui, E.
name: Aspelmeyer, M.
name: Romero-Isart, O.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We propose to optimally control the harmonic potential of a levitated nanoparticle to quantum delocalize its center-of-mass motional state to a length scale orders of magnitude larger than the quantum zero-point motion. Using a bang-bang control of the harmonic potential, including the possibility to invert it, the initial ground-state-cooled levitated nanoparticle coherently expands to large scales and then contracts to the initial state in a time-optimal way. We show that this fast loop protocol can be used to enhance force sensing as well as to dramatically boost the entangling rate of two weakly interacting nanoparticles. We parameterize the performance of the protocol, and therefore the macroscopic quantum regime that could be explored, as a function of displacement and frequency noise in the nanoparticle's center-of-mass motion. This noise analysis accounts for the sources of decoherence relevant to current experiments.
description: 5+5 pages, 4+1 figures
Metz, Johann B. / Rendtorff, Trutz (Hrsg.), Die Theologie in der interdisziplinären Forschung
Creators: name: Goertz, Hans-Jürgen
Publisher: name: Ökumenische Rundschau
Year: 2025

description: Ökumenische Rundschau, Bd. 21 Nr. 3 (1972): Ökumenische Rundschau, Band 21, Heft 3
/ 13:189 "Asymptotic expansions of Whittaker functions"/MS, "Improved asymptotic expansions", "Tactoids", related to [24] and [31]. Verwey to Onsager 1948, April 19. Oster to Onsager 1948, June 30.
Creators: name: Onsager, Lars
Publisher: name: Unknown
Year: 0

description: Tidligere referanse: 13:188
Bond-order modulated staggered flux phase for the $t{-}J$ model on the square lattice
Creators: name: Weber, Cedric
name: Poilblanc, Didier
name: Capponi, Sylvain
name: Mila, Frederic
name: Jaudet, Cyril
Publisher: name: arXiv
Year: 2006
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Motivated by the observation of inhomogeneous patterns in some high-T$_c$ cuprate compounds, several variational Gutzwiller-projected wave-functions with built-in charge and bond order parameters are proposed for the extended $t-J-V$ model on the square lattice at low doping. First, following a recent Gutzwiller-projected mean-field approach by one of us (Phys. Rev. B. {\bf 72}, 060508(R) (2005)), we investigate, as a function of doping and Coulomb repulsion, the stability of the staggered flux phase with respect to small spontaneous modulations of squared unit cells ranging from $2\times 2$ to $\sqrt{32}\times\sqrt{32}$. It is found that a $4\times 4$ bond-order (BO) modulation appears spontaneously on top of the staggered flux pattern for hole doping around 1/8. A related wave-function is then constructed and optimized accurately and its properties studied extensively using an approximation-free variational Monte Carlo scheme. Finally, the competition of the BO-modulated staggered flux wave-function w.r.t. the d-wave RVB wave-function or the commensurate flux state is investigated. It is found that a short range Coulomb repulsion penalizes the d-wave superconductor and that a moderate Coulomb repulsion brings them very close in energy. Our results are discussed in connection to the STM observations in the under-doped regime of some cuprates.
description: 10 pages, 9 figures
Moments of the particle phase-space density at freeze-out and coincidence probabilities
Creators: name: Bialas, A.
name: Czyz, W
name: Zalewski, K.
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: It is pointed out that the moments of phase-space particle density at freeze-out can be determined from the coincidence probabilities of the events observed in multiparticle production. A method to measure the coincidence probabilities is described and its validity examined.
description: Latex, six pages, no figures
Triality for Homogeneous Polynomials
Creators: name: Schaposnik, Laura P.
name: Schulz, Sebastian
Publisher: name: arXiv
Year: 2020
Subjects: subject: Rings and Algebras (math.RA)
subject: Differential Geometry (math.DG)
subject: Representation Theory (math.RT)
subject: FOS: Mathematics

description: Through the triality of ${\rm SO}(8,\mathbb{C})$, we study three interrelated homogeneous basis of the ring of invariant polynomials of Lie algebras, which give the basis of three Hitchin fibrations, and identify the explicit automorphisms that relate them.
Fair and Diverse Allocation of Scarce Resources
Creators: name: Anahideh, Hadis
name: Kang, Lulu
name: Nezami, Nazanin
Publisher: name: arXiv
Year: 2020
Subjects: subject: Optimization and Control (math.OC)
subject: FOS: Mathematics

description: We aim to design a fairness-aware allocation approach to maximize the geographical diversity and avoid unfairness in the sense of demographic disparity. During the development of this work, the COVID-19 pandemic is still spreading in the U.S. and other parts of the world on large scale. Many poor communities and minority groups are much more vulnerable than the rest. To provide sufficient vaccine and medical resources to all residents and effectively stop the further spreading of the pandemic, the average medical resources per capita of a community should be independent of the community's demographic features but only conditional on the exposure rate to the disease. In this article, we integrate different aspects of resource allocation and seek a synergistic intervention strategy that gives vulnerable populations with higher priority when distributing medical resources. This prevention-centered strategy is a trade-off between geographical coverage and social group fairness. The proposed principle can be applied to other scarce resources and social benefits allocation.