cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Multiple valued sections of vector bundles: the reparametrization theorem for $Q$-valued functions revisited
Creators: name: Stuvard, Salvatore
Publisher: name: arXiv
Year: 2017
Subjects: subject: Analysis of PDEs (math.AP)
subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: 49Q15

description: We analyze a notion of multiple valued sections of a vector bundle over an abstract smooth Riemannian manifold, which was suggested by W. Allard in the unpublished note "Some useful techniques for dealing with multiple valued functions" and generalizes Almgren's $Q$-valued functions. We study some relevant properties of such $Q$-multisections and apply the theory to provide an elementary and purely geometric proof of a delicate reparametrization theorem for multi-valued graphs which plays an important role in the regularity theory for higher codimension area minimizing currents à la Almgren-De Lellis-Spadaro.
description: V2 is the final version, to appear in Comm. Anal. Geom
i3PosNet: Instrument Pose Estimation from X-Ray in temporal bone surgery
Creators: name: Kügler, David
name: Sehring, Jannik
name: Stefanov, Andrei
name: Stenin, Igor
name: Kristin, Julia
name: Klenzner, Thomas
name: Schipper, Jörg
name: Mukhopadhyay, Anirban
Publisher: name: arXiv
Year: 2018
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Image and Video Processing (eess.IV)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Purpose: Accurate estimation of the position and orientation (pose) of surgical instruments is crucial for delicate minimally invasive temporal bone surgery. Current techniques lack in accuracy and/or line-of-sight constraints (conventional tracking systems) or expose the patient to prohibitive ionizing radiation (intra-operative CT). A possible solution is to capture the instrument with a c-arm at irregular intervals and recover the pose from the image. Methods: i3PosNet infers the position and orientation of instruments from images using a pose estimation network. Said framework considers localized patches and outputs pseudo-landmarks. The pose is reconstructed from pseudo-landmarks by geometric considerations. Results: We show i3PosNet reaches errors less than 0.05mm. It outperforms conventional image registration-based approaches reducing average and maximum errors by at least two thirds. i3PosNet trained on synthetic images generalizes to real x-rays without any further adaptation. Conclusion: The translation of Deep Learning based methods to surgical applications is difficult, because large representative datasets for training and testing are not available. This work empirically shows sub-millimeter pose estimation trained solely based on synthetic training data.
description: Accepted at International journal of computer assisted radiology and surgery pending publication
Coordination-driven learning in multi-agent problem spaces
Creators: name: Barton, Sean L.
name: Waytowich, Nicholas R.
name: Asher, Derrik E.
Publisher: name: arXiv
Year: 2018
Subjects: subject: Multiagent Systems (cs.MA)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: We discuss the role of coordination as a direct learning objective in multi-agent reinforcement learning (MARL) domains. To this end, we present a novel means of quantifying coordination in multi-agent systems, and discuss the implications of using such a measure to optimize coordinated agent policies. This concept has important implications for adversary-aware RL, which we take to be a sub-domain of multi-agent learning.
description: AAAI Fall Symposium 2018, Concept Paper
On the Measurability of Stochastic Fourier Integral Operators
Creators: name: Oberguggenberger, Michael
name: Schwarz, Martin
Publisher: name: arXiv
Year: 2019
Subjects: subject: Analysis of PDEs (math.AP)
subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 35S30, 35L45, 35R60

description: This work deals with the measurability of Fourier integral operators (FIOs) with random phase and amplitude functions. The key ingredient is the proof that FIOs depend continuously on their phase and amplitude functions, taken from suitable classes. The results will be applied to the solution FIO of the transport equation with spatially random transport speed as well as to FIOs describing waves in random media.
title: Οι επιπτώσεις της πανδημίας covid-19 στη ναυτιλία και πιο συγκεκριμένα στην αγορά των εμπορευματοκιβωτίων
title: The effects of the covid-19 pandemic on shipping and more specifically on the container market
titleType: AlternativeTitle
Creators: name: Kαλογεροπούλου, Γεωργία
Publisher: name: Πανεπιστήμιο Δυτικής Αττικής
Year: 2023
Subjects: Εμπορευματοκιβώτια
Covid-19
Πανδημία
Ναυτιλία
Τάσεις αγοράς
Θαλάσσιες μεταφορές

description: Η εργασία μελετά της ναυτιλιακές τάσεις πριν και μετά την αγορά ανά κλάδο. Επιπλέονπαρέχει ένα ιστορικό πλαίσιο για τη μεταφορά εμπορευματοκιβωτίων, τη σημασία του κλάδου για την παγκόσμια οικονομία και την εμφάνιση του COVID-19 ως απειλής για τον κλάδο.
On the local structure of oriented graphs -- a case study in flag algebras
Creators: name: Gilboa, Shoni
name: Glebov, Roman
name: Hefetz, Dan
name: Linial, Nati
name: Morgenstern, Avraham
Publisher: name: arXiv
Year: 2019
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics

description: Let $G$ be an $n$-vertex oriented graph. Let $t(G)$ (respectively $i(G)$) be the probability that a random set of $3$ vertices of $G$ spans a transitive triangle (respectively an independent set). We prove that $t(G) + i(G) \geq \frac{1}{9}-o_n(1)$. Our proof uses the method of flag algebras that we supplement with several steps that make it more easily comprehensible. We also prove a stability result and an exact result. Namely, we describe an extremal construction, prove that it is essentially unique, and prove that if $H$ is sufficiently far from that construction, then $t(H) + i(H)$ is significantly larger than $\frac{1}{9}$. We go to greater technical detail than is usually done in papers that rely on flag algebras. Our hope is that as a result this text can serve others as a useful introduction to this powerful and beautiful method.
description: 51 pages, 11 figures
Nanoscale electromechanics to measure thermal conductivity, expansion and interfacial losses
Creators: name: Mathew, John P.
name: Patel, Raj
name: Borah, Abhinandan
name: Maliakkal, Carina B.
name: Abhilash, T. S.
name: Deshmukh, Mandar M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We study the effect of localized Joule heating on the mechanical properties of doubly clamped nanowires under tensile stress. Local heating results in systematic variation of the resonant frequency; these frequency changes result from thermal stresses that depend on temperature dependent thermal conductivity and expansion coefficient. The change in sign of the linear expansion coefficient of InAs is reflected in the resonant response of the system near a bath temperature of 20 K. Using finite element simulations to model the experimentally observed frequency shifts, we show that the thermal conductivity of a nanowire can be approximated in the 10-60 K temperature range by the empirical form $κ=b$T W/mK, where the value of $b$ for a nanowire was found to be $b=0.035$ W/mK$^2$, significantly lower than bulk values. Also, local heating allows us to independently vary the temperature of the nanowire relative to the clamping points pinned to the bath temperature. We suggest a loss mechanism (dissipation $\sim10^{-4}-10^{-5}$) originating from the interfacial clamping losses between the metal and the semiconductor nanostructure.
Suppressing material loss in the visible and near-infrared range for functional nanophotonics using bandgap engineering
Creators: name: Wang, Mingsong
name: Krasnok, Alex
name: Lepeshov, Sergey
name: Hu, Guangwei
name: Jiang, Taizhi
name: Fang, Jie
name: Korgel, Brian A.
name: Alu, Andrea
name: Zhneg, Yuebing
Publisher: name: Springer Nature Limited
Year: 2020
Subjects: nanophotonics

description: All-dielectric nanostructures have recently opened exciting opportunities for functional nanophotonics, owing to their strong optical resonances along with low material loss in the near-infrared range. Pushing these concepts to the visible range is hindered by their larger absorption coefﬁcient, thus encouraging the search for alternative dielectrics for nanopho- tonics. Here, we employ bandgap engineering to synthesize hydrogenated amorphous Si nanoparticles (a-Si:H NPs) offering ideal features for functional nanophotonics. We observe signiﬁcant material loss suppression in a-Si:H NPs in the visible range caused by hydrogenation-induced bandgap renormalization, producing strong higher-order resonant modes in single NPs with Q factors up to ~100 in the visible and near-IR range. We also realize highly tunable all-dielectric meta-atoms by coupling a-Si:H NPs to photochromic spiropyran molecules. ~70% reversible all-optical tuning of light scattering at the higher-order resonant mode under a low incident light intensity is demonstrated. Our results promote the development of high-efﬁciency visible nanophotonic devices.
Toward a Better Monitoring Statistic for Profile Monitoring via Variational Autoencoders
Creators: name: Sergin, Nurettin
name: Yan, Hao
Publisher: name: arXiv
Year: 2019
Subjects: subject: Machine Learning (cs.LG)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: Wide accessibility of imaging and profile sensors in modern industrial systems created an abundance of high-dimensional sensing variables. This led to a a growing interest in the research of high-dimensional process monitoring. However, most of the approaches in the literature assume the in-control population to lie on a linear manifold with a given basis (i.e., spline, wavelet, kernel, etc) or an unknown basis (i.e., principal component analysis and its variants), which cannot be used to efficiently model profiles with a nonlinear manifold which is common in many real-life cases. We propose deep probabilistic autoencoders as a viable unsupervised learning approach to model such manifolds. To do so, we formulate nonlinear and probabilistic extensions of the monitoring statistics from classical approaches as the expected reconstruction error (ERE) and the KL-divergence (KLD) based monitoring statistics. Through extensive simulation study, we provide insights on why latent-space based statistics are unreliable and why residual-space based ones typically perform much better for deep learning based approaches. Finally, we demonstrate the superiority of deep probabilistic models via both simulation study and a real-life case study involving images of defects from a hot steel rolling process.
description: Journal of Quality Technology 53 (2021) 454-473
Anomalous solutions to nonlinear hyperbolic equations
Creators: name: Oberguggenberger, Michael
Publisher: name: arXiv
Year: 2020
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35D10 (Primary), 35B65, 35L60, 35L70 (Secondary)

description: The behavior of sufficiently regular solutions to semilinear hyperbolic equations has attracted a great deal of attention in the past decades, concerning local/global existence, finite time blow-up, critical exponents, and propagation of singularities. Solutions of lower regularity may exhibit unexpected (anomalous) propagation of singularities. The purpose of this paper is to present various striking examples that seemingly have not been addressed in the literature so far. The key issue is the interpretation of the nonlinear operations.
Fragmentation of AdS$_5$-Kerr Black Holes
Creators: name: McInnes, Brett
Publisher: name: arXiv
Year: 2020
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Black hole spacetimes asymptotic to five-dimensional anti-de Sitter spacetime are of great interest in connection with the string-gauge duality. In the rotating case, such black holes tend to become unstable, in several different ways, if their specific angular momenta fall in certain ranges. Here we consider the well-known Emparan-Myers fragmentation instability for singly rotating AdS$_5$-Kerr black holes, paying particular attention to the case where the specific angular momentum exceeds the asymptotic AdS$_5$ curvature length scale.
description: 23 pages, 8 Figures
Synthesis and Dual-Mode Electrochromism of Anisotropic Monoclinic Nb12O29 Colloidal Nanoplatelets
Creators: name: Lu, Hsin-Che
name: Ghosh, Sandeep
name: Katyal, Naman
name: Lakhanpal, Vikram S.
name: Gearba-Dolocan, Ioana R.
name: Henkelman, Graeme
name: Milliron, Delia J.
Publisher: name: The University of Texas at Austin
Year: 2020
Subjects: Electrochromism

description: Transition metal oxide nanocrystals with dual-mode electrochromism hold promise for smart windows enabling spec- trally selective solar modulation. We have developed the colloidal synthesis of anisotropic monoclinic Nb12O29 nanoplatelets (NPLs) to investigate the dual-mode electrochromism of niobium oxide nanocrystals. The precursor for synthesizing NPLs was prepared by mixing NbCl5 and oleic acid to form a complex that was subsequently heated to form an oxide-like structure capped by oleic acid, denoted as niobium oxo cluster. By initiating the synthesis using niobium oxo clusters, preferred growth of NPLs over other poly- morphs was observed. The structure of the synthesized NPLs was examined by X-ray diffraction in conjunction with simulations, revealing that the NPLs are monolayer monoclinic Nb12O29, thin in the [100] direction and extended along the b and c directions. Besides having monolayer thickness, NPLs show decreased intensity of Raman signal from Nb-O bonds with higher bond order when compared to bulk monoclinic Nb12O29, as interpreted by calculations. Progressive electrochemical reduction of NPL films led to absorbance in the near-infrared region (stage 1) followed by absorbance in both the visible and near-infrared regions (stage 2), thus exhibiting dual-mode electrochromism. The mechanisms underlying these two processes were distinguished electrochemically by cyclic voltammetry to determine the extent to which ion intercalation limits the kinetics, and by verifying the presence of localized electrons following ion intercalation using X-ray photoelectron spectroscopy. Both results support that the near-infrared absorption results from capacitive charging and the onset of visible absorption in the second stage is caused by ion intercalation.
Thermodynamic Volume of Cosmological Solitons
Creators: name: Mbarek, Saoussen
name: Mann, Robert B.
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: We present explicit expressions of the thermodynamic volume inside and outside the cosmological horizon of Eguchi-Hanson solitons in general odd dimensions. These quantities are calculable and well-defined regardless of whether or not the regularity condition for the soliton is imposed. For the inner case, we show that the reverse isoperimetric inequality is not satisfied for general values of the soliton parameter $a$, though a narrow range exists for which the inequality does hold. For the outer case, we find that the mass $M_{out}$ satisfies the maximal mass conjecture and the volume is positive. We also show that, by requiring $M_{out}$ to yield the mass of dS spacetime when the soliton parameter vanishes, the associated cosmological volume is always positive.
description: 16 pages, 2 figures, 3 tables
Statistical properties of superflares on solar-type stars with Kepler data
Creators: name: Notsu, Yuta
name: Maehara, Hiroyuki
name: Shibayama, Takuya
name: Honda, Satoshi
name: Notsu, Shota
name: Namekata, Kosuke
name: Nogami, Daisaku
name: Shibata, Kazunari
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Superflares are flares that release total energy 10$\sim$10$^{4}$ times greater than that of the biggest solar flares with energy of $\sim$10$^{32}$ erg. We searched superflares on solar-type stars (G-type main sequence stars) using the Kepler 30-min (long) and 1-min (short) cadence data. We found more than 1500 superflares on 279 stars from 30-min cadence data (Q0-6) and 187 superflares on 23 stars from 1-min cadence data (Q0-17). The bolometric energy of detected superflares ranges from the order of 10$^{32}$ erg to 10$^{36}$ erg. Using these data, we found that the occurrence frequency ($dN/dE$) of superflares is expressed as a power-law function of flare energy ($E$) with the index of -1.5 for $10^{33}
description: 8 pages, 9 figures, to appear in the proceedings of "The 19th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun (CS19), Uppsala, Sweden, 06-10 June 2016"
AutoSNAP: Automatically Learning Neural Architectures for Instrument Pose Estimation
Creators: name: Kügler, David
name: Uecker, Marc
name: Kuijper, Arjan
name: Mukhopadhyay, Anirban
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Despite recent successes, the advances in Deep Learning have not yet been fully translated to Computer Assisted Intervention (CAI) problems such as pose estimation of surgical instruments. Currently, neural architectures for classification and segmentation tasks are adopted ignoring significant discrepancies between CAI and these tasks. We propose an automatic framework (AutoSNAP) for instrument pose estimation problems, which discovers and learns the architectures for neural networks. We introduce 1)~an efficient testing environment for pose estimation, 2)~a powerful architecture representation based on novel Symbolic Neural Architecture Patterns (SNAPs), and 3)~an optimization of the architecture using an efficient search scheme. Using AutoSNAP, we discover an improved architecture (SNAPNet) which outperforms both the hand-engineered i3PosNet and the state-of-the-art architecture search method DARTS.
description: Accepted at MICCAI 2020 Preparing code for release at https://github.com/MECLabTUDA/AutoSNAP
Treatment of overlapping gaseous absorption with the correlated-k method in hot Jupiter and brown dwarf atmosphere models
Creators: name: Amundsen, David S.
name: Tremblin, Pascal
name: Manners, James
name: Baraffe, Isabelle
name: Mayne, Nathan J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: The correlated-k method is frequently used to speed up radiation calculations in both one-dimensional and three-dimensional atmosphere models. An inherent difficulty with this method is how to treat overlapping absorption, i.e. absorption by more than one gas in a given spectral region. We have evaluated the applicability of three different methods in hot Jupiter and brown dwarf atmosphere models, all of which have been previously applied within models in the literature: (i) Random overlap, both with and without resorting and rebinning, (ii) equivalent extinction and (iii) pre-mixing of opacities, where (i) and (ii) combine k-coefficients for different gases to obtain k-coefficients for a mixture of gases, while (iii) calculates k-coefficients for a given mixture from the corresponding mixed line-by-line opacities. We find that the random overlap method is the most accurate and flexible of these treatments, and is fast enough to be used in one-dimensional models with resorting and rebinning. In three-dimensional models such as GCMs it is too slow, however, and equivalent extinction can provide a speed-up of at least a factor of three with only a minor loss of accuracy while at the same time retaining the flexibility gained by combining k-coefficients computed for each gas individually. Pre-mixed opacities are significantly less flexible, and we also find that particular care must be taken when using this method in order to to adequately resolve steep variations in composition at important chemical equilibrium boundaries. We use the random overlap method with resorting and rebinning in our one-dimensional atmosphere model and equivalent extinction in our GCM, which allows us to e.g. consistently treat the feedback of non-equilibrium chemistry on the total opacity and therefore the calculated P-T profiles in our models.
description: Accepted for publication in Astronomy & Astrophysics. 10 pages, 13 figures, 4 tables
Preferential Control of Forward Reaction Kinetics in Hydrogels Crosslinked with Reversible Conjugate Additions
Creators: name: FitzSimons, Thomas M.
name: Oentoro, Felicia
name: Shanbhag, Tej V.
name: Anslyn, Eric V.
name: Rosales, Adrianne M.
Publisher: name: The University of Texas at Austin
Year: 2020
Subjects: Hydrogels

description: Molecular substitutions were used to demonstrate preferential control over the kinetic rate constants in a poly(ethylene glycol)-based hydrogel with two different reversible thia-conjugate addition reactions. A strong electron withdrawing nitrile group on the conjugate acceptor showed a 20-fold increase in the forward rate constant over a neutral withdrawing group, while the reverse rate constant only increased 6-fold. Rheometry experiments demonstrated that the hydrogel plateau modulus was primarily dictated by reaction equilibrium, while the stress relaxation characteristics of the hydrogel were dominated by the reverse rate constant. Furthermore, the dynamic crosslinking allowed the hydrogel to rapidly and spontaneously self-heal. These results indicate that decoupling the kinetic rate constants of bond exchange allow systematic control over dynamic covalent hydrogel bulk properties, such as their adaptability, stress relaxation ability, and self-healing properties.
From Filter Paper to Functional Actuator by Poly(ionic liquid)-Modified Graphene Oxide
Creators: name: Song, Haojie
name: Lin, Huijuan
name: Antonietti, Markus
name: Yuan, Jiayin
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: A commercially available membrane filter paper composed of mixed cellulose esters bearing typically an interconnected pore structure was transformed into a stimuli-responsive bilayer actuator by depositing a thin film of poly(ionic liquid)-modified graphene oxide sheets (GO-PIL) onto the filter paper. In acetone vapor, the as-synthesized bilayer actuator bent readily into multiple loops at a fast speed with the GO-PIL top film inwards. Upon pulling back into air the actuator recovered their original shape. The asymmetric swelling of the top GO-PIL film and the bottom porous filter paper towards organic vapor offers a favorably synergetic function to drive the actuation. The PIL polymer chains in the hybrid film were proven crucial to enhance the adhesion strength between the GO sheets and the adjacent filter paper to avoid interfacial delamination and thus improve force transfer. The overall construction allows a prolonged lifetime of the bilayer actuator under constant operation, especially when compared to that of the GO/filter paper bilayer actuator without PIL.
description: 23 pages, 7 figures
Local iterative block-diagonalization of gapped Hamiltonians: a new tool in singular perturbation theory
Creators: name: Del Vecchio, Simone
name: Froehlich, Juerg
name: Pizzo, Alessandro
name: Rossi, Stefano
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: In this paper the local iterative Lie-Schwinger block-diagonalization method, introduced in [FP], [DFPR1], and [DFPR2] for quantum chains, is extended to higher-dimensional quantum lattice systems with Hamiltonians that can be written as the sum of an unperturbed gapped operator, consisting of a sum of on-site terms, and a perturbation consisting of bounded interaction potentials of short range mutltiplied by a real coupling constant t. Our goal is to prove that the spectral gap above the ground-state energy of such Hamiltonians persists for sufficiently small values of |t|, independently of the size of the lattice. New ideas and concepts are necessary to extend our method to systems in dimension d > 1: As in our earlier work, a sequence of local block-diagonalization steps based on judiciously chosen unitary conjugations of the original Hamiltonian is introduced. The supports of effective interaction potentials generated in the course of these block-diagonalization steps can be identified with what we call minimal rectangles contained in the lattice, a concept that serves to tackle combinatorial problems that arise in the course of iterating the block-diagonalization steps. For a given minimal rectangle, control of the effective interaction potentials generated in each block-diagonalization step with support in the given rectangle is achieved by exploiting a variety of rather subtle mechanisms which include, for example, the use of weighted sums of paths consisting of overlapping rectangles and of large denominators, expressed in terms of sums of orthogonal projections, that serve to control analogous sums of projections in the numerators resulting from the unitary conjugations of the interaction potential terms involved in the local block-diagonalization step.
description: 47 pages
Pulsar radio emission mechanism I : On the amplification of Langmuir waves in the linear regime
Creators: name: Rahaman, Sk. Minhajur
name: Mitra, Dipanjan
name: Melikidze, George I.
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Observations suggest that in normal period radio pulsars, coherent curvature radiation is excited within 10$\%$ of the light cylinder. The coherence is attributed to Langmuir mode instability in a relativistically streaming one-dimensional plasma flow along the open magnetic field lines. In this work, we use a hot plasma treatment to solve the hydrodynamic dispersion relation of Langmuir mode for realistic pulsar parameters. The solution involves three scenarios of two-stream instability viz., driven by high energy beams, due to longitudinal drift that leads to a separation of electron-positron distribution functions in the secondary plasma and due to cloud-cloud interaction causing spatial overlap of two successive secondary plasma clouds. We find that sufficient amplification can be obtained only for the latter two scenarios. Our analysis shows that longitudinal drift is characterized by high growth rates only for certain multi-polar surface field geometry. For these configurations, very high growth rates are obtained starting from a few tens of km from the neutron star surface, which then falls monotonically with increasing distance. For cloud-cloud overlap, growth rates become high starting only after a few hundred km from the surface, which first increases and then decreases with increasing distance. A spatial window of up to around a 1000 km above the neutron star surface has been found where large amplitude Langmuir waves can be excited while the pair plasma is dense enough to account for high brightness temperature.
description: Accepted for publication in MNRAS
Counterfactual Explanation Based on Gradual Construction for Deep Networks
Creators: name: Jung, Hong-Gyu
name: Kang, Sin-Han
name: Kim, Hee-Dong
name: Won, Dong-Ok
name: Lee, Seong-Whan
Publisher: name: arXiv
Year: 2020
Subjects: subject: Machine Learning (cs.LG)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: To understand the black-box characteristics of deep networks, counterfactual explanation that deduces not only the important features of an input space but also how those features should be modified to classify input as a target class has gained an increasing interest. The patterns that deep networks have learned from a training dataset can be grasped by observing the feature variation among various classes. However, current approaches perform the feature modification to increase the classification probability for the target class irrespective of the internal characteristics of deep networks. This often leads to unclear explanations that deviate from real-world data distributions. To address this problem, we propose a counterfactual explanation method that exploits the statistics learned from a training dataset. Especially, we gradually construct an explanation by iterating over masking and composition steps. The masking step aims to select an important feature from the input data to be classified as a target class. Meanwhile, the composition step aims to optimize the previously selected feature by ensuring that its output score is close to the logit space of the training data that are classified as the target class. Experimental results show that our method produces human-friendly interpretations on various classification datasets and verify that such interpretations can be achieved with fewer feature modification.
description: The first two authors contributed equally to this work
Tensor structure on the Kazhdan-Lusztig category for affine $\mathfrak{gl}(1|1)$
Creators: name: Creutzig, Thomas
name: McRae, Robert
name: Yang, Jinwei
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Algebra (math.QA)
subject: High Energy Physics - Theory (hep-th)
subject: Representation Theory (math.RT)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 17B65, 17B69, 18M15, 81T40

description: We show that the Kazhdan-Lusztig category $KL_k$ of level-$k$ finite-length modules with highest-weight composition factors for the affine Lie superalgebra $\widehat{\mathfrak{gl}(1|1)}$ has vertex algebraic braided tensor supercategory structure, and that its full subcategory $\mathcal{O}_k^{fin}$ of objects with semisimple Cartan subalgebra actions is a tensor subcategory. We show that every simple $\widehat{\mathfrak{gl}(1|1)}$-module in $KL_k$ has a projective cover in $\mathcal{O}_k^{fin}$, and we determine all fusion rules involving simple and projective objects in $\mathcal{O}_k^{fin}$. Then using Knizhnik-Zamolodchikov equations, we prove that $KL_k$ and $\mathcal{O}_k^{fin}$ are rigid. As an application of the tensor supercategory structure on $\mathcal{O}_k^{fin}$, we study certain module categories for the affine Lie superalgebra $\widehat{\mathfrak{sl}(2|1)}$ at levels $1$ and $-\frac{1}{2}$. In particular, we obtain a tensor category of $\widehat{\mathfrak{sl}(2|1)}$-modules at level $-\frac{1}{2}$ that includes relaxed highest-weight modules and their images under spectral flow.
description: 46 pages, to appear in Int. Math. Res. Not
Data-Driven Fault Diagnosis Analysis and Open-Set Classification of Time-Series Data
Creators: name: Lundgren, Andreas
name: Jung, Daniel
Publisher: name: arXiv
Year: 2020
Subjects: subject: Machine Learning (stat.ML)
subject: Machine Learning (cs.LG)
subject: Signal Processing (eess.SP)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: 62H30

description: Fault diagnosis of dynamic systems is done by detecting changes in time-series data, for example residuals, caused by system degradation and faulty components. The use of general-purpose multi-class classification methods for fault diagnosis is complicated by imbalanced training data and unknown fault classes. Another complicating factor is that different fault classes can result in similar residual outputs, especially for small faults, which causes classification ambiguities. In this work, a framework for data-driven analysis and open-set classification is developed for fault diagnosis applications using the Kullback-Leibler divergence. A data-driven fault classification algorithm is proposed which can handle imbalanced datasets, class overlapping, and unknown faults. In addition, an algorithm is proposed to estimate the size of the fault when training data contains information from known fault realizations. An advantage of the proposed framework is that it can also be used for quantitative analysis of fault diagnosis performance, for example, to analyze how easy it is to classify faults of different magnitudes. To evaluate the usefulness of the proposed methods, multiple datasets from different fault scenarios have been collected from an internal combustion engine test bench to illustrate the design process of a data-driven diagnosis system, including quantitative fault diagnosis analysis and evaluation of the developed open set fault classification algorithm.
description: Preprint, 44 pages, 14 figures
BiqBin: a parallel branch-and-bound solver for binary quadratic problems with linear constraints
Creators: name: Gusmeroli, Nicolò
name: Hrga, Timotej
name: Lužar, Borut
name: Povh, Janez
name: Siebenhofer, Melanie
name: Wiegele, Angelika
Publisher: name: arXiv
Year: 2020
Subjects: subject: Optimization and Control (math.OC)
subject: FOS: Mathematics

description: We present BiqBin, an exact solver for linearly constrained binary quadratic problems. Our approach is based on an exact penalty method to first efficiently transform the original problem into an instance of Max-Cut, and then to solve the Max-Cut problem by a branch-and-bound algorithm. All the main ingredients are carefully developed using new semidefinite programming relaxations obtained by strengthening the existing relaxations with a set of hypermetric inequalities, applying the bundle method as the bounding routine and using new strategies for exploring the branch-and-bound tree. Furthermore, an efficient C implementation of a sequential and a parallel branch-and-bound algorithm is presented. The latter is based on a load coordinator-worker scheme using MPI for multi-node parallelization and is evaluated on a high-performance computer. The new solver is benchmarked against BiqCrunch, GUROBI, and SCIP on four families of (linearly constrained) binary quadratic problems. Numerical results demonstrate that BiqBin is a highly competitive solver. The serial version outperforms the other three solvers on the majority of the benchmark instances. We also evaluate the parallel solver and show that it has good scaling properties. The general audience can use it as an on-line service available at http://www.biqbin.eu.
Sharp-Interface Continuum Thermodynamics of multicomponent fluid systems with interfacial mass
Creators: name: Bothe, Dieter
Publisher: name: arXiv
Year: 2020
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 80A17, 35Q35, 35R37, 76T30, 80A22

description: We revisit the sharp-interface continuum thermodynamics of two-phase multicomponent fluid systems with interfacial mass. Since the published work is not fully consistent, we provide a rigorous derivation of the local balance equations and the entropy production rates, including all relevant steps and mathematical tools. Special emphasis is put on an axiomatic form of the entropy principle which, at the same time, allows for an efficient closure process. The latter builds on an appropriate representation of the entropy production rates, which is based on structural information being obtained from a more refined model which includes partial momenta and is given in an appendix. The closure relations obtained for the one-sided bulk-interface species transfer rates are further investigated, which leads to a novel model for mass transfer at fluid interfaces, influenced by the presence of adsorbed surface active agents. We finally compare our results in detail with the existing literature on continuum thermodynamics of two-phase multicomponent fluid systems with interfacial mass.
description: Accepted version with significantly extended introduction
Beyond CO2 equivalence: The impacts of methane on climate, ecosystems, and health
Creators: name: Mar, Kathleen A.
name: Unger, Charlotte
name: Walderdorff, Ludmila
name: Butler, Tim
Publisher: name: Freie Universität Berlin
Year: 2022
Subjects: subject: Methane
subject: Climate governance
subject: Air pollution
subject: International policy
subject: Short-lived climate pollutants
subject: Global warming potential
subject: 500 Naturwissenschaften und Mathematik::550 Geowissenschaften, Geologie::550 Geowissenschaften

description: In this article we review the physical and chemical properties of methane (CH4) relevant to impacts on climate, ecosystems, and air pollution, and examine the extent to which this is reflected in climate and air pollution governance. Although CH4 is governed under the UNFCCC climate regime, its treatment there is limited to the ways in which it acts as a “CO2 equivalent” climate forcer on a 100-year time frame. The UNFCCC framework neglects the impacts that CH4 has on near-term climate, as well its impacts on human health and ecosystems, which are primarily mediated by methane’s role as a precursor to tropospheric ozone. Frameworks for air quality governance generally address tropospheric ozone as a pollutant, but do not regulate CH4 itself. Methane’s climate and air quality impacts, together with its alarming rise in atmospheric concentrations in recent years, make it clear that mitigation of CH4 emissions needs to be accelerated globally. We examine challenges and opportunities for further progress on CH4 mitigation within the international governance landscapes for climate change and air pollution.
Mode changing, subpulse drifting and nulling in four component conal pulsar PSR J2321+6024
Creators: name: Rahaman, Sk. Minhajur
name: Basu, Rahul
name: Mitra, Dipanjan
name: Melikidze, George I.
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: In this study, we report on a detailed single pulse polarimetric analysis of the radio emission from the pulsar J2321+6024 (B2319+60) observed with the Giant Metrewave Radio Telescope, over wide frequencies ranging between 300 to 500 MHz and widely separated observing sessions. The pulsar profile shows the presence of four distinct conal components and belongs to a small group of pulsars classified as a conal quadrupole profile type. The single pulse sequence reveals the presence of three distinct emission modes, A, B, and ABN showing subpulse drifting. Besides, there were sequences when the pulsar did not show any drifting behaviour suggesting the possibility of a new emission state, which we have termed as mode C. The evolution of the mode changing behavior was seen during the different observing sessions with different abundance as well as the average duration of the modes seen on each date. The drifting periodicities were 7.8$\pm$0.3 $P$, 4.3$\pm$0.4 $P$, and 3.1$\pm$0.2 $P$ in the modes A, B and ABN respectively, and showed large phase variations within the mode profile. The pulsar also showed the presence of orthogonal polarization modes, particularly in the leading and trailing components, which has different characteristics for the stronger and weaker pulses. However, no correlation was found between the emission modes and their polarization behavior, with the estimated emission heights remaining roughly constant throughout. We have used the Partially Screened Gap model to understand the connection between drifting, mode changing, and nulling.
description: Accepted for publication in MNRAS
A Transfer Learning Framework for Anomaly Detection Using Model of Normality
Creators: name: Aburakhia, Sulaiman
name: Tayeh, Tareq
name: Myers, Ryan
name: Shami, Abdallah
Publisher: name: arXiv
Year: 2020
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Convolutional Neural Network (CNN) techniques have proven to be very useful in image-based anomaly detection applications. CNN can be used as deep features extractor where other anomaly detection techniques are applied on these features. For this scenario, using transfer learning is common since pretrained models provide deep feature representations that are useful for anomaly detection tasks. Consequentially, anomaly can be detected by applying similarly measure between extracted features and a defined model of normality. A key factor in such approaches is the decision threshold used for detecting anomaly. While most of the proposed methods focus on the approach itself, slight attention has been paid to address decision threshold settings. In this paper, we tackle this problem and propose a welldefined method to set the working-point decision threshold that improves detection accuracy. We introduce a transfer learning framework for anomaly detection based on similarity measure with a Model of Normality (MoN) and show that with the proposed threshold settings, a significant performance improvement can be achieved. Moreover, the framework has low complexity with relaxed computational requirements.
description: 7 pages, 4 figures, 2 tables, conference: The 11th Annual IEEE Information Technology, Electronics and Mobile Communication Conference "IEEE IEMCON", Vancouver, Canada, November 2020. IEEE IEMCON'20' best paper award in the category of Industrial Automation and Control Systems Technology
Psychische Erkrankungen und ihre Repräsentation in den sozialen Medien durch Kinder und Jugendliche: Ein besorgniserregender Trend [Mental Illness and Its Representation on Social Media by Children and Adolescents: A Worrying Trend]
Creators: name: Blohm, Dean
Publisher: name: Zenodo
Year: 2023
Subjects: Munchausen by Internet
Factitious Disorder
Social Media

description: In den letzten Jahren lässt sich ein besorgniserregender Trend beobachten, bei dem sich vor allem Kinder und Jugendliche in den sozialen Medien mit ihnen vermeintlich diagnostizierten psychischen Erkrankungen präsentieren, diese romantisieren oder andere dazu aufrufen, Fachpersonal zu misstrauen und zum Mittel der „Selbstdiagnose“ zu greifen. Diese Arbeit bietet einen Überblick über dieses Phänomen, analysiert die Problematik und bietet einen Ausblick für die Zukunft. Als Methode wurden mehrere Primärstudien analysiert und ihre Erkenntnisse dargelegt, um einen Erklärungsansatz für die Ursache für den Anklang von Romantisierungen psychischer Erkrankungen in sozialen Netzwerken zu liefern und Handlungsempfehlungen im Umgang mit Patienten des Kindes- und Jugendalters, die sich aufgrund von Einflüssen sozialer Netzwerke selbst eine Diagnose gestellt haben, zu geben. Die Analyse ergab, dass die Repräsentation von psychischen Erkrankungen in sozialen Medien eine äußerst komplexe Dynamik aufweist. Sie umfasst die romantisierte Darstellung von Krankheitsbildern, die Verbreitung von gesundheitsbezogenen Fehlinformationen sowie die Beeinflussung der Wahrnehmung psychischer Erkrankungen durch Kinder und Jugendliche. Eine immer stärkere Verbreitung des sogenannten Münchhausen by Internet Phänomens kann beobachtet werden. Basierend auf den Erkenntnissen dieser Arbeit werden Empfehlungen zum Umgang mit Betroffenen von Münchhausen by Internet im klinischen Setting gemacht. Eben jene Maßnahmen sollten darauf abzielen, dem Patienten zu verstehen zu geben, dass man Verständnis für ihn hat und ihm helfen will. Auch wird empfohlen, dass mehr Aufklärung über psychische Erkrankungen, gerade bei Kindern und Jugendlichen, stattfinden sollte. Diese Übersichtsarbeit bietet eine Grundlage für zukünftige Forschung und Maßnahmen zur Förderung der psychischen Gesundheit von Kindern und Jugendlichen in einer digitalisierten Welt.
Optimized methodology for the calculation of electrostriction from first-principles
Creators: name: Tanner, Daniel S. P.
name: Bousquet, Eric
name: Janolin, Pierre-Eymeric
Publisher: name: arXiv
Year: 2020
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: In this work we present a new method for the calculation of the electrostrictive properties of materials using density functional theory. The method relies on the thermodynamical equivalence, in a dielectric, of the quadratic mechanical responses (stress or strain) to applied electric stimulus (electric or polarisation fields) to the strain or stress dependence of its dielectric susceptibility or stiffness tensors. Comparing with current finite-field methodologies for the calculation of electrostriction, we demonstrate that our presented methodology offers significant advantages of efficiency, robustness, and ease of use. These advantages render tractable the highthroughput theoretical investigation into the largely unknown electrostrictive properties of materials.
The robustness of interdependent networks under the interplay between cascading failures and virus propagation
Creators: name: Zhao, Dawei
name: Wang, Zhen
name: Xiao, Gaoxi
name: Gao, Bo
name: Wang, Lianhai
Publisher: name: arXiv
Year: 2016
Subjects: subject: Social and Information Networks (cs.SI)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: Cascading failures and epidemic dynamics, as two successful application realms of network science, are usually investigated separately. How do they affect each other is still one open, interesting problem. In this letter, we couple both processes and put them into the framework of interdependent networks, where each network only supports one dynamical process. Of particular interest, they spontaneously form a feedback loop: virus propagation triggers cascading failures of systems while cascading failures suppress virus propagation. Especially, there exists crucial threshold of virus transmissibility, above which the interdependent networks collapse completely. In addition, the interdependent networks will be more vulnerable if the network supporting virus propagation has denser connections; otherwise the interdependent systems are robust against the change of connections in other layer(s). This discovery differs from previous framework of cascading failure in interdependent networks, where better robustness usually needs denser connections. Finally, to protect interdependent networks we also propose the control measures based on the identification capability. The larger this capability, more robustness the interdependent networks will be.
Evaluation of the systematic shifts of a ${}^{40}\textrm{Ca}^+-{}^{27}\textrm{Al}^+$ optical clock
Creators: name: Cui, Kaifeng
name: Chao, Sijia
name: Sun, Chenglong
name: Wang, Shaomao
name: Zhang, Ping
name: Wei, Yuanfei
name: Yuan, Jinbo
name: Cao, Jian
name: Shu, Hualin
name: Huang, Xueren
Publisher: name: arXiv
Year: 2020
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Quantum-logic-based ${}^{27}\textrm{Al}^+$ optical clock has been demonstrated in several schemes as there are different choices of the auxiliary ion species. In this paper, we present the first detailed evaluation of the systematic shift and the total uncertainty of an ${}^{27}\textrm{Al}^+$ optical clock sympathetically cooled by a ${}^{40}\textrm{Ca}^+$ ion. The total systematic uncertainty of the ${}^{40}\textrm{Ca}^+ - {}^{27}\textrm{Al}^+$ quantum logic clock has been estimated to be $7.9 \times 10^{-18}$, which was mainly limited by the uncertainty of the quadratic Zeeman shift. By comparing the frequency of two counter-propagating clock beams on the same ion, we measured the frequency stability to be $3.7 \times 10^{-14} /\sqrtτ$.
description: 8 pages, 3 figures, 3 tables