Miracle-dz/UniFAR-FTUs huggingface dataset:
Squeeze Training for Adversarial Robustness

The vulnerability of deep neural networks (DNNs) to adversarial examples has attracted great attention in the machine learning community. The problem is related to non-flatness and non-smoothness of normally obtained loss landscapes. Training augmented with adversarial examples (a.k.a., adversarial training) is considered as an effective remedy. In this paper, we highlight that some collaborative examples, nearly perceptually indistinguishable from both adversarial and benign examples yet show extremely lower prediction loss, can be utilized to enhance adversarial training. A novel method is therefore proposed to achieve new state-of-the-arts in adversarial robustness. Code: https://github.com/qizhangli/ST-AT.
ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Density Structure of Centrally Concentrated Prestellar Cores from Multiscale Observations

Starless cores represent the initial stage of evolution toward (proto)star formation, and a subset of them, known as prestellar cores, with high density (∼ 106 cm−3 or higher) and being centrally concentrated are expected to be embryos of (proto)stars. Determining the density profile of prestellar cores therefore provides an important opportunity to gauge the initial conditions of star formation. In this work, we perform rigorous modeling to estimate the density profiles of three nearly spherical prestellar cores among a sample of five highly dense cores detected by our recent observations. We employed multiscale observational data of the (sub)millimeter dust continuum emission, including those obtained by SCUBA-2 on the James Clerk Maxwell Telescope with a resolution of ∼ 5600 au and by multiple Atacama Large Millimeter/submillimeter Array observations with a resolution as high as ∼ 480 au. We are able to consistently reproduce the observed multiscale dust continuum images of the cores with a simple prescribed density profile, which bears an inner region of flat density and an r −2 profile toward the outer region. By utilizing the peak density and the size of the inner flat region as a proxy for the dynamical stage of the cores, we find that the three modeled cores are most likely unstable and prone to collapse. The sizes of the inner flat regions, as compact as ∼ 500 au, signify them as being the highly evolved prestellar cores rarely found to date.
Out-of-sample R2: estimation and inference

Out-of-sample prediction is the acid test of predictive models, yet an independent test dataset is often not available for assessment of the prediction error. For this reason, out-of-sample performance is commonly estimated using data splitting algorithms such as cross-validation or the bootstrap. For quantitative outcomes, the ratio of variance explained to total variance can be summarized by the coefficient of determination or in-sample $R^2$, which is easy to interpret and to compare across different outcome variables. As opposed to the in-sample $R^2$, the out-of-sample $R^2$ has not been well defined and the variability on the out-of-sample $\hat{R}^2$ has been largely ignored. Usually only its point estimate is reported, hampering formal comparison of predictability of different outcome variables. Here we explicitly define the out-of-sample $R^2$ as a comparison of two predictive models, provide an unbiased estimator and exploit recent theoretical advances on uncertainty of data splitting estimates to provide a standard error for the $\hat{R}^2$. The performance of the estimators for the $R^2$ and its standard error are investigated in a simulation study. We demonstrate our new method by constructing confidence intervals and comparing models for prediction of quantitative $\text{Brassica napus}$ and $\text{Zea mays}$ phenotypes based on gene expression data.
The ‘hit’ phenomenon: a mathematical model of human dynamics interactions as a stochastic process

A mathematical model for the ‘hit’ phenomenon in entertainment within a society is presented as a stochastic process of human dynamics interactions. The model uses only the advertisement budget time distribution as an input, and word-of-mouth (WOM), represented by posts on social network systems, is used as data to make a comparison with the calculated results. The unit of time is days. The WOM distribution in time is found to be very close to the revenue distribution in time. Calculations for the Japanese motion picture market based on the mathematical model agree well with the actual revenue distribution in time.
ELECTROMAGNETIC WAVES NEAR THE PROTON CYCLOTRON FREQUENCY: STEREO OBSERVATIONS

Transverse, near-circularly polarized, parallel-propagating electromagnetic waves around the proton cyclotron frequency were found sporadically in the solar wind throughout the inner heliosphere. They could play an important role in heating and accelerating the solar wind. These low-frequency waves (LFWs) are intermittent but often occur in prolonged bursts lasting over 10 minutes, named “LFW storms. ” Through a comprehensive survey of them from Solar Terrestrial Relations Observatory A using dynamic spectral wave analysis, we have identified 241 LFW storms in 2008, present 0.9% of the time. They are left-hand (LH) or right-hand (RH) polarized in the spacecraft frame with similar characteristics, probably due to Doppler shift of the same type of waves or waves of intrinsically different polarities. In rare cases, the opposite polarities are observed closely in time or even simultaneously. Having ruled out interplanetary coronal mass ejections, shocks, energetic particles, comets, planets, and interstellar ions as LFW sources, we discuss the remaining generation scenarios: LH ion cyclotron instability driven by greater perpendicular temperature than parallel temperature or by ring-beam distribution, and RH ion fire hose instability driven by inverse temperature anisotropy or by cool ion beams. The investigation of solar wind conditions is compromised by the bias of the one-dimensional Maxwellian fit used for plasma data calibration. However, the LFW storms are preferentially detected in rarefaction regions following fast winds and when the magnetic field is radial. This preference may be related to the ion cyclotron anisotropy instability in fast wind and the minimum in damping along the radial field.
Quantization of AdS3 Black Holes in External Fields: Semiclassical Results from Pure Gravity

s2 1 1d-dimensional anti - de Sitter (AdS) gravity is quantized in the presence of an external scalar field. We find that the coupling between the scalar field and gravity is equivalently described by a perturbed conformal field theory at the boundary of AdS 3. This allows us to perform a microscopic computation of the transition rates between black hole states due to absorption and induced emission of the scalar field. Detailed thermodynamic balance then yields Hawking radiation as spontaneous emission, and we find agreement with the semiclassical result, including greybody factors. This result also has application to four and five-dimensional black holes in supergravity. (S0031-9007(98)07124-5) Ifg, Cg › Igrav fgg 1 Imatter fC; gg . (1) In view of the difficulty to quantize this system in a complete way. Hawking proposed to treat g as a classical, fixed background, in the presence of which the field C is quantized (2). The drawback in this approach is that the black hole is unaffected by the emission of radiation. No reference to black hole microstates is made, and accounting for back reaction has proven to be a notoriously difficult problem. In this paper we suggest a different route, in which the microstates of the black hole play an explicit role. This approach is more akin to the old fashioned treatment of radiation from, say, an atom. The quantized atom can be excited by absorbing energy from the external radiation field, or it can also decay via induced emission of radi- ation by giving away energy to the field. Existence of a thermodynamical equilibrium then implies that sponta- neous emission must occur, with rate given in terms of the coefficients for absorption and induced emission. it is a variation of that approach that we aim to develop here. That is, we treat the gravitational field g as quantum de- grees of freedom, whereas the matter field C will remain classical. In view of the lack of a consistent quantum theory of four-dimensional gravity we will work in the framework of anti-de Sitter (AdS) gravity in 2 1 1 dimensions. s2 1 1d-dimensional gravity with a negative cosmological constant is know to have black hole solutions (3) which have proved to be a useful laboratory for the study of the microscopical properties of black holes. At the same time s2 1 1d-dimensional gravity is almost trivial. More precisely, it is topological, at least in the absence of matter fields. As a consequence the dynamics of the gravitational degrees of freedom is described by a conformal field theory (CFT) at the boundary, i.e., the asymptotic region
Flow Structures Around an Oscillating-Wing Power Generator

Power extraction from wind and water streams using flapping wings is known to be an alternative method to harvest renewable energy. The vortical flow structures around and in the wake of a NACA0012 airfoil oscillating with non-sinusoidal pitching and plunging motions are investigated using digital particle image velocimetry and compared with Navier–Stokes computations to give insight into the physics that determine the performance of an oscillating-wing power generator for a plunge amplitude of 1.05 chords, reduced frequency of 0.8, pitch amplitude of 73 deg, pivot points at quarter and mid-chords, phase angles of 90 and 110 deg, and stroke reversal times (ΔTR) of 0.1 (rapid reversal) to 0.5 (sinusoidal reversal) at a Reynolds number of Re=1100. As the airfoil rotation speed during pitch reversals is increased, vortex shedding occurs earlier with higher strength. As the phase angle by which the pitching motion leads the plunging motion is increased, the shed vortex convection distance is also increased. T.
The lattice Boltzmann equation for natural convection in a two-dimensional cavity with a partially heated wall

The lattice Boltzmann equation method in two dimensions was used to analyse natural convective flows. The method was validated with experiments in an open cavity with one of the vertical walls divided into two parts, the lower part conductive, the upper part and all the other walls adiabatic. An upward thermal boundary layer formed near the conductive wall. This layer gave way to a wall plume. The numerical results compared well with experiments in the laminar ($Ra\,{=}\,2.0\,{\times}\,10^9$) and transition ($Ra\,{=}\,4.9\,{\times}\,10^9$) regimes. The behaviour of the starting plume was numerically studied for Rayleigh numbers Ra from $10^6$ to $4.9\times 10^9$. The wall plume grows in three stages: in the first with constant acceleration, in the second with constant ascending velocity and in the third with negative acceleration due to the presence of the top boundary layer. The acceleration of the first stage and the velocity of the second both scale with the Rayleigh number.
A Process Study of the Dependence of Ice Crystal Absorption on Particle Geometry: Application to Aircraft Radiometric Measurements of Cirrus Cloud in the Terrestrial Window Region

Abstract The processes that contribute to the absorption of infrared radiation by atmospheric ice crystals are studied. The processes are separated into the geometric optics (i.e., refraction, internal, and external reflection) and above-edge (i.e., the capture of photons beyond the physical cross section of the particle via tunneling through an inertial barrier) contributions. The geometric optics and above-edge contributions to ice crystal absorption are compared and contrasted assuming ice spheres, randomly oriented hexagonal ice columns, and randomly oriented ice aggregates (i.e., systematically increasing particle complexity). The geometric optics and above-edge absorption coefficients have been calculated using the complex angular momentum approximation applied to the ice sphere, and a composite method has been used to calculate the two sets of absorption coefficients for the hexagonal ice column and ice aggregate based on the finite difference time domain and improved geometric optics methods. The .
Content-based and Knowledge-enriched Representations for Classification Across Modalities: A Survey

This survey documents representation approaches for classification across different modalities, from purely content-based methods to techniques utilizing external sources of structured knowledge. We present studies related to three paradigms used for representation, namely (a) low-level template-matching methods, (b) aggregation-based approaches, and (c) deep representation learning systems. We then describe existing resources of structure knowledge and elaborate on the need for enriching representations with such information. Approaches that utilize knowledge resources are presented next, organized with respect to how external information is exploited, i.e., (a) input enrichment and modification, (b) knowledge-based refinement and (c) end-to-end knowledge-aware systems. We subsequently provide a high-level discussion to summarize and compare strengths/weaknesses of the representation/enrichment paradigms proposed, and conclude the survey with an overview of relevant research findings and possible directions for future work.
A unified mathematical programming formulation of strain driven and interior point algorithms for shakedown and limit analysis

A mathematical programming formulation of strain‐driven path‐following strategies to perform shakedown and limit analysis for perfectly elastoplastic materials in an FEM context is presented. From the optimization point of view, standard arc‐length strain‐driven elastoplastic analyses, recently extended to shakedown, are identified as particular decomposition strategies used to solve a proximal point algorithm applied to the static shakedown theorem that is then solved by means of a convergent sequence of safe states. The mathematical programming approach allows: a direct comparison with other non‐linear programming methods, simpler convergence proofs and duality to be exploited. Owing to the unified approach in terms of total stresses, the strain‐driven algorithms become more effective and less non‐linear with respect to a self‐equilibrated stress formulation and easier to implement in the existing codes performing elastoplastic analysis. The elastic domain is represented avoiding any linearization of the yield function so improving both the accuracy and the performance. Better results are obtained using two different finite elements, one with a good behavior in the elastic range and the other suitable for performing elastoplastic analysis. The proposed formulation is compared with a specialized implementation of the primal–dual interior point method suitable to solve the problems at hand. Copyright © 2011 John Wiley & Sons, Ltd.
Effects of irradiation on Hall probe sensitivity

Four Hall probes from two different manufacturers were exposed to increasing amounts of radiation at the Advanced Test Accelerator and were compared periodically to a nuclear magnetic resonance (NMR) gaussmeter at magnetic field values of 2 to 8 kG. The radiation was primarily bremsstrahlung from a 45-MeV electron beam. The probes were mounted near a beam dump, along with LiF thermoluminescent detectors to keep track of the cumulative dose. The data show a threshold near 100 kRd, beyond which the probes tend to lose sensitivity and perform outside their nominal error limits. It is conjectured that the loss in sensitivity may be caused by crystal dislocations in the InAs Hall chip arising from neutrons generated in gamma-n reactions. It is observed that the radiation effects are not monotonic with cumulative dose, and in some cases appear to go away at the higher doses; this is attributed to annealing of the probe material during or in between the successive irradiations. <<ETX>>
Experiment on the geometry of the fine-structure regions in fully turbulent fluid

An attempt has been made to identify the geometric character of the random fine-structure regions dispersed in fully turbulent fluid. The technique was measure-ment of two-position coincidence functions for the presence of velocity fine-structure. In this primitive approach, we tried to distinguish among only three possible categories for the random shapes: (a) ‘blobs’, (b) ‘rods’ and (c) 'slabs’, depending on whether three mean orthogonal dimensions of the domains were such that (a) all were of the same order, (b) one was an order larger than the other two, or (c) one was an order smaller than the other two. Highly idealized paradigms for these three categories were studied analytically: the two-position coincidence functions were computed for the cases of (a) spheres, (b) circular cylinders and (c) plane slabs, each field containing randomly sized elements distributed randomly in space with a homogeneous and isotropic distribution. Comparison of the measured coincidence functions with these three paradigms suggests that the fine-structure regions are more nearly of ‘rod-like’ geometry than like either of the other two. No attempt was made to distinguish shapes which might be called 'strips’.
Absolutely continuous invariant measures for piecewise expanding C2 transformations in Rn on domains with cusps on the boundaries

Abstract Let Ω be a bounded region in Rn and let be a partition of Ω into a finite number of subsets having piecewise C2 boundaries. The boundaries may contain cusps. Let τ: Ω → Ω be piecewise C2 on and expanding in the sense that there exists α > 1 such that for any i = 1, 2,…,m, where is the derivative matrix of and ‖·‖ is the euclidean matrix norm. The main result provides a lower bound on α which guarantees the existence of an absolutely continuous invariant measure for τ.
Studies of relaxation oscillations in organic dye lasers

The transient phenomena of relaxation oscillations and "initial spikes" in organic dye lasers are studied experimentally and theoretically. Both damped relaxation oscillations and initial spikes are clearly observed in N 2 laser-pumped dye lasers under appropriate conditions which are furthermore shown to agree with theoretical considerations. Linearized rate equations obtained with small-signal approximation are used to describe the initial-spiking phenomenon; for the more general phenomenon of relaxation oscillations computer solutions of the coupled rate equations are obtained. Comparisons with experimental observations show excellent qualitative agreement. Based on the results of these studies, a general technique using the idea of controlled resonator transients is described for tunable subnanosecond pulse generation from laser-pumped dye lasers in the near UV and the visible region of the spectrum.
SOME FAMILIES OF OPERATIONS IN MORAVA K-THEORY

This paper gives an account of operations of Steenrod type in Morava K-theory K(n)*( ). Our research was originally stimulated by the paper of U. Wurgler [61; unfortunately, equation (2.11) does not appear to follow and this seems to prevent his Oi from being stable operations. We therefore attack the problem of giving an algebraically defined set of "reduced powers," using the relationship between K(n)-theory and Lubin-Tate formal group laws. We hope to return to the tom Dieck approach considered by Wurgler in future joint work with him; we will also consider Bockstein type operations in a joint sequel to the present work. We would like to thank Urs Wurgler for correspondence on this material, and suggesting Theorem 18. We would also like to thank the SERC and Universitat Bern for support whilst this research was in progress. NOTE: For all background information we refer to Ravenel's book [5]. We consider the problem of constructing operations in K(n)-theory analogous to the classical Steenrod reduced powers, by using a multiplicative operation in an enlarged version of K(n)-theory, and then picking off certain terms in this. We relate the operations thus produced to elements in the dual cooperation ring and show that we have enough indecomposables to generate the operation algebra K(n)*(K(n)). We also find that our reduced powers satisfy a "cyclic" Cartan formula (see Theorem 14). Finally we use an infinite dimensional generalisation of Hensel's Lemma to lift operations to E(n)-theory.
Ideology, Legitimation and Collective Action: Evidence from Chile on the Mechanism of Ideological Inversion

Abstract:We present evidence on a social mechanism of legitimation—ideological inversion—proposing that a fantasy consensus deters collective actions oriented toward social change, even in contexts were individuals support transformations. This fantasy consensus emerges as individuals infer the order's validity mainly from the practices of others, which are largely constrained by social structures. Relying on a factorial survey experiment conducted in Chile, our results support the two main hypotheses from ideological inversion: people systematically overestimate the support for the status quo, and this overestimation has a deterrent effect on collective actions oriented toward social change. We argue that ideological inversion helps explain how legitimation crises often remain hidden, and therefore how political crisis often emerge abruptly. For instance, before the revolt of 2019 Chile was perceived as an example of social stability within Latin America, yet after an ordinary subway fare hike the country erupted in an unrelenting and massive wave of protests. Our findings suggest that the social support for the status quo previously perceived in Chile was a fantasy consensus enforced by constrained practices, and that this fantasy was very effective until recently in deterring social change. Ideological inversion thus provides a mechanism that contributes to explain the stability of social structures and inequalities regardless of individual dispositions or shared norms.
Spatial and kinematical lopsidedness of atomic hydrogen in the Ursa Major group of galaxies

We have carried out the harmonic analysis of the atomic hydrogen (HI) surface density maps and the velocity fields for 11 galaxies belonging to the Ursa Major group, over a radial range of 4-6 disc scalelengths in each galaxy. This analysis gives the radial variation of spatial lopsidedness, quantified by the Fourier amplitude A(1) of the m = 1 component normalized to the average value. The kinematical analysis gives a value for the elongation of the potential to be similar to 10 per cent. The mean amplitude of spatial lopsidedness is found to be similar to 0.14 in the inner disc, similar to the field galaxies, and is smaller by a factor of similar to 2 compared to the Eridanus group galaxies. It is also shown that the average value of A(1) does not increase with the Hubble type, contrary to what is seen in field galaxies. We argue that the physical origin of lopsidedness in the Ursa Major group of galaxies is tidal interactions, albeit weaker and less frequent than in Eridanus. Thus systematic studies of lopsidedness in groups of galaxies can provide dynamical clues regarding the interactions and evolution of galaxies in a group environment.