Miracle-dz/UniFAR-FTUs huggingface dataset:
A Proximal Alternating Direction Method of Multiplier for Linearly Constrained Nonconvex Minimization

Consider the minimization of a nonconvex differentiable function over a polyhedron. A popular primal-dual first-order method for this problem is to perform a gradient projection iteration for the augmented Lagrangian function and then update the dual multiplier vector using the constraint residual. However, numerical examples show that this approach can exhibit "oscillation" and may not converge. In this paper, we propose a proximal alternating direction method of multipliers for the multi-block version of this problem. A distinctive feature of this method is the introduction of a "smoothed" (i.e., exponentially weighted) sequence of primal iterates, and the inclusion, at each iteration, to the augmented Lagrangian function a quadratic proximal term centered at the current smoothed primal iterate. The resulting proximal augmented Lagrangian function is inexactly minimized (via a gradient projection step) at each iteration while the dual multiplier vector is updated using the residual of the linear constraints. When the primal and dual stepsizes are chosen sufficiently small, we show that suitable "smoothing" can stabilize the "oscillation", and the iterates of the new proximal ADMM algorithm converge to a stationary point under some mild regularity conditions. Furthermore, when the objective function is quadratic, we establish the linear convergence of the algorithm. Our proof is based on a new potential function and a novel use of error bounds.
Introduction to the theory of quantized fields

This site is also available in the following languages: Български Català Deutsch Ελληνικά English Español Français Hrvatski Italiano Norsk/Bokmål Polski Português Русский Slovensky Svenska ( ) ( ) Start by marking “Introduction to the Theory of Quantized Fields” as Want to Read: Want to Read saving. Want to Read. Currently Reading. Read. Introduction to the Th by D.V. Shirkov. Other editions. The quantum theory that one nds agrees with the usual picture of canonical quantization that one learns in standard eld theory. The quantum theory also comes with a representation of the inhomogeneous Lorentz group (the Poincar ́e group) that arises from an analytic continuation of the quantization of the Euclidean group. Thus the two fundamental points of view mesh to one. We rst investigate a special case that relates to the Gaussian path integral and the free quantum eld. We then give the general construction that applies for bosonic non-linear elds. Introduction to Quantum Field Theory. 24 . In this chapter we give a dierent perspective on the ordinary quantum theory of a single spinless, positive msss-m particle on Rd−1. In this edition we have rewritten the chapters that discuss the methods of continuous integration and the renormalization group, which are two topics in theory that have become extremely important in recent years. We have also reworked and supplemented the sections on the complete Green functions.This work was done in an atmosphere of friendly advice and fruitful discussions with our colleagues from the Steklov Mathematical Institute of the USSR Academy of Sciences and of the Laboratory of Theoretical Physics of the Joint Institute of Nuclear Studies, to whom we are extremely grateful. Introduction To The Theory Of Quantized Fields
The Longitudinal Driving Behavior of a Vehicle Assisted with Lv2 Driving Automation: An Empirical Study

As the number of automated vehicles in our transportation system increases, it becomes increasingly important to understand how automation affects their driving behavior. This study defines and tests a methodology based on optimization methods to incorporate the longitudinal driving behavior of automated vehicles in the Wiedemann 99 car-following model. A pilot study was recently conducted in Portugal using a Mercedes-Benz of 2017 assisted with level 2 driving automation to gather empirical data. In total, 61 car-following events were used to support the calibration and validation tasks. The calibration error sustains the methodology’s descriptive capability to simulate the driving behavior of AVs, and the validation error sustains that the calibrated model parameters can reproduce the dynamic driving behavior of AVs with reasonable consistency and robustness. A total of seven model parameters were estimated and are in line with the trends often described in the literature on automated vehicles but also highlight differences that can be explained by different development and deployment strategies. Nevertheless, since empirical data from automated vehicles are hard to get, the presented work findings are also valuable for improving and validating future modeling efforts.
Short-term and long-term irreversibility in particle suspensions undergoing small and large amplitude oscillatory stress

The short-term and long-term irreversible behaviors of suspensions of rigid particles in oscillatory shear flow are studied by measuring the evolution of complex viscosity in time and applying of nonlinear analysis of the responded strain signal under the controlled-stress mode, and complemented by optical measurements on the particle motion. The short-term transition time for the system to reach a quasisteady state is an approximately bell-shaped function of the amplitude of the strain response, thus showing a critical strain amplitude accounting for the peak transition time. The short-term behavior is caused by the particle self-organization due to collisions between particles. At longer time scales, the complex viscosity of the suspension increases when probed by forces that elicit small strain amplitudes and decreases when stresses that result in large strain amplitudes are applied. It is proposed that the long-term behavior for stresses eliciting small strain amplitude is induced by the shear-induced diffusion of particles which self-organize into a crystal-like microstructure that can be easily annulled in oscillatory flow with large strain amplitude, while for stresses causing large strain amplitude the dominant microstructure is formed immediately via the oscillation.
THE TYPECASTING OF ACTIVE GALACTIC NUCLEI: Mrk 590 NO LONGER FITS THE ROLE

We present multiwavelength observations that trace more than 40 yr in the life of the active galactic nucleus (AGN) in Mrk 590, traditionally known as a classic Seyfert 1 galaxy. From spectra recently obtained from Hubble Space Telescope, Chandra, and the Large Binocular Telescope, we find that the activity in the nucleus of Mrk 590 has diminished so significantly that the continuum luminosity is a factor of 100 lower than the peak luminosity probed by our long-baseline observations. Furthermore, the broad emission lines, once prominent in the UV/optical spectrum, have all but disappeared. Since AGN type is defined by the presence of broad emission lines in the optical spectrum, our observations demonstrate that Mrk 590 has now become a “changing-look” AGN. If classified by recent optical spectra, Mrk 590 would be a Seyfert ∼1.9−2, where the only broad emission line still visible in the optical spectrum is a weak component of Hα. As an additional consequence of this change, we have definitively detected UV narrow-line components in a Type 1 AGN, allowing an analysis of these emission-line components with high-resolution COS spectra. These observations challenge the historical paradigm that AGN type is only a consequence of the line-of-sight viewing angle toward the nucleus in the presence of a geometrically flattened, obscuring medium (i.e., the torus). Our data instead suggest that the current state of Mrk 590 is a consequence of the change in luminosity, which implies the black hole accretion rate has significantly decreased.
Managing Competing Demands in a Teacher Shortage Context: The Impact of Teacher Shortages on Principal Leadership Practices

Purpose: Teacher shortages disrupt multiple aspects of school functioning. Negative effects of shortages are linked to poor outcomes for students, teachers, and organizational climate and culture. However, less attention has been paid to the impact of shortages on principals’ leadership activities. Research Methods/Approach: This study uses qualitative data from 23 principals in four Oklahoma school districts to describe the impact of teacher shortages on principals’ leadership practice and the extent to which principals alter leadership behaviors in relation to shortages. Findings: Findings offer new evidence suggesting teacher supply, principal leadership, and organizational functioning are tightly coupled. Specifically, principals experienced competing managerial demands as they reported stronger impacts of shortages on tasks associated with organizational management, instructional management, and internal relations, while indirect or minor impacts were reported for administrative and external relations tasks. Implications: As teacher shortages increase across the U.S., this study highlights the cumulative impacts of shortages on schools and offers implications for school leadership, policy, and practice.
PIV-POD Investigation of the Wake of a Sharp-Edged Flat Bluff Body Immersed in a Shallow Channel Flow

This paper reports particle-image velocimetry measurements of instantaneous velocity fields in the wake of a sharp-edged bluff body immersed vertically in a shallow smooth open channel flow. The maximum flow velocity was 0.19 m/s and the Reynolds number based on the water depth was 18,270. The purpose of the present study is to show the vertical variation of the velocity field in the near region of a shallow wake. Measurements of the flow field in the vertical central plane and in the horizontal near-bed, mid-depth, and near-surface planes were taken. Then, the mean flow quantities such as the mean velocity, turbulence intensity, and Reynolds stress fields were investigated. In addition, the proper orthogonal decomposition technique was used to reconstruct the velocity fields to investigate the energetic vortical structures. The results showed that the largest recirculation zone in the mean velocity fields occurred in the mid-depth velocity field, while the smallest one occurred near the bed. Also, the fluid was entrained from the sides toward the wake central plane in the three horizontal velocity fields but with different rates. This behavior was attributed to the existence of quasi-streamwise vortices near the boundaries. In addition, patterns of ejection and sweep events near the free surface similar to the features commonly observed near the wall-bounded flows were observed. DOI: 10.1115/1.3054283
Designing bulk acoustic wave resonators for parametric amplification of spin waves

approved: Pallavi Dhagat Spintronics is an emerging field of research dealing with devices that can potentially exploit the additional degree of freedom provided by the electron spin along with or instead of the con­ ventional electronic charge. One of the most promising aspects of spintronics is the potential use of magnetostatic spin waves as information carriers in logic devices, where information is encoded in the electron spin. A major obstacle in making this a practically viable alternative to conventional electronics is the very large intrinsic spin wave damping in most known magnetic materials. In this work, we propose a new technique of parametrically amplifying spin waves by means of acoustic resonators. An equivalent electrical model of an acoustic resonator was de­ veloped to efficiently design the acoustic resonators for the desired frequency ranges. Backward volume magnetostatic spin waves were measured in Yttrium Iron Garnet films at frequencies of 1.7 GHz or higher, requiring acoustic resonators to be designed for at least 3.4 GHz or higher for parametric amplification. Acoustic resonators with resonance frequency of 4 GHz were fab­ ricated. c ©Copyright by Pratim Chowdhury November 12, 2013 All Rights Reserved Designing Bulk Acoustic Wave Resonators for Parametric Amplification of Spin Waves
Nonlinear behavior of the surface waves between two magnetic fluid layers

In this paper, we provide an extensive stability analysis of the surface waves between two immiscible infinite layers of magnetic liquids. This subject seems to have a long history with relevance to fluid mechanics as well as technological and industrial applications. The effects of gravitation and a uniform oblique magnetic field are taken into account. The analytical solutions of the nonlinear problem are achieved in the framework of the perturbation analysis methods, in order to treat finite amplitude waves and then determine the stability criteria of the considered problem. The various stability criteria of the traveling waves are investigated. Also, the solitary-wave solutions at the liquid–liquid interface are discussed. In the end, the effort comes across as a number of snapshots of neutral stability curves in the parameter space. The influence of different parameters governing the flow on the stability behavior of the system is discussed in detail.
Some limit theorems for the total progeny of a branching process

We consider a branching process in which each individual reproduces independently of all others and has probability a j (j = 0, 1, · · ·) of giving rise to j progeny in the following generation. It is assumed, without further comment, that 0 < a 0, a 0 + a 1 < 1.
The application of Kalman smoother theory to the estimation of 4DVAR error statistics

Modern atmospheric data assimilation theory is dominated by the four-dimensional variational (4DVAR) and Kalman filter/smoother approaches. Both generate analysis weights (explicitly or implicitly) which are dynamically determined by the assimilation model. A Kalman smoother is basically a generalization of the Kalman filter which can process future observations. In control theory, a generalization of 4DVAR called Pontryagin optimization can account for an imperfect assimilating model. Pontryagin optimization and the fixed-interval Kalman smoother are equivalent when both methods use the same statistical information. We use the equivalence between Pontryagin optimization and the Kalman smoother to examine the effect of the perfect model assumption on the error statistics and analysis weights of the 4DVAR algorithm. This is done by developing the Kalman smoother equations for a very simple assimilating model. A procedure for diagnosing the effect of model error, based on the observational cost function, is also developed. DOI: 10.1034/j.1600-0870.1996. t01-1-00003.x
Observation of, and temporal variations in, solar p-mode multiplet frequency asymmetries at ℓ= 2

The predominant contribution to the frequency splitting of low-l solar p modes arises from the rotation of the solar interior and this lifts the frequency degeneracy in l to give a symmetric pattern where the observed (synodic) separation between adjacent m (i.e. for \Deltam\=1) is similar to400 nHz. Magnetic fields can also contribute to the splitting, but they do so in such a way as to introduce asymmetries in the arrangement of the components within each multiplet. In disc-integrated data this effect may become apparent when lgreater than or equal to2. Here, we attempt to extract estimates of the frequency asymmetries at l=2 from the analysis of disc-integrated data collected by the ground-based Birmingham Solar Oscillations Network (BiSON) and the GOLF instrument on board the ESA/NASA SOHO satellite. Our analyses demonstrate that we have evidence for there being non-zero asymmetries present (significance approximate to3-4sigma) during an epoch coincident with high levels of surface activity close to the maximum of solar cycle 23. The asymmetries are indistinguishable from zero at minimum levels of activity near the cycle 22/23 boundary. We also compare the observed asymmetries with those calculated from a model that is based upon the recent predictions of Moreno-Insertis & Solanki. While the level of agreement between the two is found to be reasonable, the observations suggest (though with poor constraints placed upon this) that the influence on the mode frequencies of high-latitude activity may not be as strong as in the model.
Bayesian Model Averaging With Applications to Benchmark Dose Estimation for Arsenic in Drinking Water

An important component of quantitative risk assessment involves characterizing the dose-response relationship between an environmental exposure and adverse health outcome and then computing a benchmark dose, or the exposure level that yields a suitably low risk. This task is often complicated by model choice considerations, because risk estimates depend on the model parameters. We propose using Bayesian methods to address the problem of model selection and derive a model-averaged version of the benchmark dose. We illustrate the methods through application to data on arsenic-induced lung cancer from Taiwan.
A new paradigm for fabricating bulk high-field superconductors

Superconductivity provides the enabling technology for producing high-field magnets in applications including medical body scanners and particle accelerators. The upper critical field (BC2(0)) of the superconductor ultimately limits the field that the magnet can produce. The reports about PbMo6S8 and Nb3Sn provide a new method for fabricating high-field superconductors in which superconducting materials are made in nanocrystalline form and the very fine microstructure and high density of defects present are controlled at the nanoscale to significantly increase the electron scattering and hence BC2(0). Here we show direct measurements of BC2(0) for a series of nanocrystalline niobium materials with an unprecedented maximum BC2(0) for bulk Nb of ∼3 T. We provide a theoretical description of our results, using the well-established fundamental properties of Nb, that explains why the peak in BC2(0) occurs and can predict optimal BC2(0) for other materials in this new class of nanocrystalline high-field superconductors.
A Naive Bayesian Cloud-Detection Scheme Derived fromCALIPSOand Applied within PATMOS-x

AbstractThe naive Bayesian methodology has been applied to the challenging problem of cloud detection with NOAA’s Advanced Very High Resolution Radiometer (AVHRR). An analysis of collocated NOAA-18/AVHRR and Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO)/Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) observations was used to automatically and globally derive the Bayesian classifiers. The resulting algorithm used six Bayesian classifiers computed separately for seven surface types. Relative to CALIPSO, the final results show a probability of correct detection of roughly 90% over water, deserts, and snow-free land; 82% over the Arctic; and below 80% over the Antarctic. This technique is applied within the NOAA Pathfinder Atmosphere’s Extended (PATMOS-x) climate dataset and the Clouds from AVHRR Extended (CLAVR-x) real-time product generation system. Comparisons of the PATMOS-x results with those from International Satellite Cloud Climatology Project (ISCCP) and Moder.
Spectroscopy of a Brown Dwarf Candidate in the alpha Persei Open Cluster

We report intermediate-resolution spectroscopy in the range 625-775 nm of a faint (R∼19) very late type object, discovered in two CCD images taken near the center of the α Per cluster. The spectrum shows strong absorption molecular bands, Hα emission, and KI absorption typical of late-M dwarfs; Hα varies conspicously (W λ ∼2.4-0.8 nm) is a short time scale. The effective temperature and luminosity derived from the spectrum and R,I band photometry are consistent with those expected for an α Per (age∼50 Myr) 0.07 M ⊙ substellar object
The s-eulerian polynomials have only real roots

We study the roots of generalized Eulerian polynomials via a novel approach. We interpret Eulerian polynomials as the generating polynomials of a statistic over inversion sequences. Inversion sequences (also known as Lehmer codes or subexcedant functions) were recently generalized by Savage and Schuster, to arbitrary sequences s of positive integers, which they called s-inversion sequences. Our object of study is the generating polynomial of the ascent statistic over the set of s-inversion sequences of length n. Since this ascent statistic over inversion sequences is equidistributed with the descent statistic over permutations, we call this generalized polynomial the s-Eulerian polynomial. The main result of this paper is that, for any sequence s of positive integers, the s-Eulerian polynomial has only real roots. This result is first shown to generalize several existing results about the real-rootedness of various Eulerian polynomials. We then show that it can be used to settle a conjecture of Brenti, that Eulerian polynomials for all finite Coxeter groups have only real roots, and partially settle a conjecture of Dilks, Petersen, Stembridge on type B affine Eulerian polynomials. It is then extended to several q-analogs. We show that the MacMahon-Carlitz q-Eulerian polynomial has only real roots whenever q is a positive real number, confirming a conjecture of Chow and Gessel. The same holds true for the hyperoctahedral group and the wreath product groups, confirming further conjectures of Chow and Gessel, and Chow and Mansour, respectively. Our results have interesting geometric consequences as well.
Summability of Multi-Dimensional Trigonometric Fourier Series

We consider the summability of oneand multi-dimensional trigonometric Fourier series. The Fejér and Riesz summability methods are investigated in detail. Different types of summation and convergence are considered. We will prove that the maximal operator of the summability means is bounded from the Hardy space Hp to Lp, for all p > p0, where p0 depends on the summability method and the dimension. For p = 1, we obtain a weak type inequality by interpolation, which ensures the almost everywhere convergence of the summability means. Similar results are formulated for the more general θ-summability and for Fourier transforms. MSC: Primary 42B08, 42A38, Secondary 42B30.
Interfacial Phenomena and Natural Local Time

This article addresses a modication of local time for stochastic processes, to be referred to as natural local time. It is prompted by theoretical developments arising in mathematical treatments of recent experiments and observations of phenomena in the geophysical and biological sciences pertaining to dispersion in the presence of an interface of discontinuity in dispersion coecients. The results illustrate new ways in which to use the theory of stochastic processes to infer macro scale parameters and behavior from micro scale observations in particular heterogeneous environments.
Causality violation in asymptotically flat space-times

It is shown that a region containing closed timelike lines cannot evolve from regular initial data in a singularity-free asymptotically flat space-time. Furthermore, the causality assumption made in the black-hole uniqueness proofs is justified: It is demonstrated that no physically realistc nonsingular black hole can have a causality-violating exterior. (AIP)
Oriented and aligned two-electron continua

The triply differential cross section (TDCS) for electron-impact ionization of atoms is analysed in terms of tensorial parameters representing orientation and alignment in electron - electron coincidences. Particular attention has been paid to excited alkali states because of experimental feasibility. Three dynamical models for the calculation of the TDCS have been considered. The plane-wave impulse approximation (PWIA), the first Born approximation (FBA), and the use of a correlated double continuum wavefunction as employed by Brauner et al, hereafter referred to as BBK. It is shown that the PWIA forbids any orientational effect, but allows for an alignment. The FBA generally shows an orientational dichroism, the structure of the TDCS within the FBA has been worked out for non-statistical M-state populations. Finally, final-state correlation is shown to modify drastically the FBA results even at intermediate to higher energies. Numerical calculations for H(2p) are presented for the purpose of illustration.