Miracle-dz/UniFAR-FTUs huggingface dataset:
Fast Numerical Solution of the Biharmonic Dirichlet Problem on Rectangles

A new method for the numerical solution of the first biharmonic Dirichlet problem in a rectangular domain is presented. For an $N \times N$ mesh the complexity of this algorithm is on the order of $N^2 $ arithmetic operations. Only one array of order $N \times N$ mesh the complexity of this algorithm is on the order of $N^2 $ and a workspace of size less than $10N$ are required. These results are therefore optimal and the algorithm is an order of magnitude more efficient than previously known methods with the possible exception of multi-grid. The method has an iterative part where a problem with different boundary conditions is used to precondition the original problem. It is shown that any initial error will be reduced by a factor $\varepsilon $ after at most $K = \ln ({2 / \varepsilon })$ iterations using the conjugate gradient method. The conjugate gradient method is also shown to have a superlinear rate of convergence when applied to this formulation of the problem. The purpose of this paper is to pro.
Multilevel generalized array coding for Rayleigh fading channel

An efficient multilevel coding system is proposed. Its short time delay is guaranteed by both short block component codes and parallel decoding of levels (PDL). To adopt soft-decision maximum-likelihood decoding to each level, component codes are first reconstructed in the form of generalized array codes (GAC). Various schemes are presented here and their performance obtained by computer simulation over ideal interleaved Rayleigh fading channels. Results show that the utilization of channel state information in parallel trellis decoding can obtain large coding gain for the system. For example, multilevel code (12,8,3)(12,8,3)(12,8,3) can obtain a coding gain up to 29.5 dB when BER is around 10/sup -5/.
Spatial asymptotics for the parabolic Anderson models with generalized time–space Gaussian noise

Partially motivated by the recent papers of Conus, Joseph and Khoshnevisan [Ann. Probab. 41 (2013) 2225–2260] and Conus et al. [Probab. Theory Related Fields 156 (2013) 483–533], this work is concerned with the precise spatial asymptotic behavior for the parabolic Anderson equation {∂u∂t(t,x)=12Δu(t,x)+V(t,x)u(t,x),u(0,x)=u0(x), where the homogeneous generalized Gaussian noise V(t,x) is, among other forms, white or fractional white in time and space. Associated with the Cole–Hopf solution to the KPZ equation, in particular, the precise asymptotic form limR→∞(logR)−2/3logmax|x|≤Ru(t,x)=342t3−−−√3a.s. is obtained for the parabolic Anderson model ∂tu=12∂2xxu+W˙u with the (1+1)-white noise W˙(t,x). In addition, some links between time and space asymptotics for the parabolic Anderson equation are also pursued.
Entropy production in high-energy heavy-ion collisions and the correlation of shear viscosity and thermalization time

We study entropy production in the early stage of high-energy heavy-ion collisions due to shear viscosity. We employ the second-order theory of Israel-Stewart with two different stress relaxation times, as appropriate for strong coupling or for a Boltzmann gas, respectively, and compare the hydrodynamic evolution. Based on the present knowledge of initial particle production, we argue that entropy production is tightly constrained. We derive new limits on the shear viscosity to entropy density ratio $\ensuremath{\eta}/s$, independent from elliptic flow effects, and determine the corresponding Reynolds number. Furthermore, we show that for a given entropy production bound, the initial time ${\ensuremath{\tau}}_{0}$ for hydrodynamics is correlated to the viscosity. The conjectured lower bound for $\ensuremath{\eta}/s$ provides a lower limit for ${\ensuremath{\tau}}_{0}$.
Estimating Insect Body Size From Radar Observations Using Feature Selection and Machine Learning

For insect radar observations, exploiting radar echoes from insects to accurately estimate size parameters, such as body mass, length, and width of insects, can help to identify insect species. At present, the commonly used method for estimating insect body size parameters in insect radar is to use the monotonic mapping relationship between insect radar cross section (RCS) parameters of a single frequency (mainly 9.4 GHz) and body size and obtain the empirical formula for body size estimation by polynomial fitting. However, the useful information used by the traditional methods is limited (1–2 features), and these retrieval methods are simple and with limited estimation accuracy. This article proposed a feature-selection-based machine learning method for insect body size estimation, which could effectively improve the body size parameter estimation accuracy of insect radars. First of all, based on the published insect scattering dataset (9.4 GHz, 366 specimens of 76 species), stepwise regression was used to select the optimal feature combinations for body size estimation, and then, three machine learning methods, such as random forest regression (RFR), support vector regression (SVR), and multilayer perceptron (MLP), were adopted to achieve the estimation of insect body size. Among them, RFR has the best performance (mass 18.83%, length 11.37%, and width 16.87%). Subsequently, based on the measured dataset of migratory insects (5532 specimens of 23 species), the influence of the estimation error of insect body size on the identification accuracy of migratory insect species was analyzed. When incorporating the estimation error of the feature-selection-based RFR method, the insect identification rate of 83.68% was reached.
Renormalization of massless Feynman amplitudes in configuration space

A systematic study of recursive renormalization of Feynman amplitudes is carried out both in Euclidean and in Minkowski configuration spaces. For a massless quantum field theory (QFT), we use the technique of extending associate homogeneous distributions to complete the renormalization recursion. A homogeneous (Poincare covariant) amplitude is said to be convergent if it admits a (unique covariant) extension as a homogeneous distribution. For any amplitude without subdivergences — i.e. for a Feynman distribution that is homogeneous off the full (small) diagonal — we define a renormalization invariant residue. Its vanishing is a necessary and sufficient condition for the convergence of such an amplitude. It extends to arbitrary — not necessarily primitively divergent — Feynman amplitudes. This notion of convergence is finer than the usual power counting criterion and includes cancellation of divergences.
Endpoint Strichartz estimate for the damped wave equation and its application

Recently, the Strichartz estimates for the damped wave equation was obtained by the first author except for the wave endpoint case. In the present paper, we give the Strichartz estimate in the wave endpoint case. We slightly modify the argument of Keel--Tao. Moreover, we apply the endpoint Strichartz estimate to the unconditional uniqueness for the energy critical nonlinear damped wave equation. This problem seems not to be solvable as the perturbation of the wave equation.
Evolution of Molecular Abundances in Proto-planetary Disks with Accretion Flow

We investigate the evolution of molecular abundances in a protoplanetary disk in which matter is accreting toward the central star by solving numerically the reaction equations of molecules as an initial-value problem. We obtain the abundances of molecules, both in the gas phase and in ice mantles of grains, as functions of time and position in the disk. In the region of surface density less than 102 g cm-2 (distance from the star ≳10 AU for the mass accretion rate 10-8 M☉ yr-1), cosmic rays are barely attenuated even on the midplane of the disk and produce chemically active ions such as H+3 and He+. We find that through reactions with these ions considerable amounts of CO and N2, which are initially the dominant species in the disk, are transformed into CO2, CH4, NH3, and HCN. In the regions where the temperature is low enough for these products to freeze onto grains, they accumulate in ice mantles. As the matter migrates toward inner warmer regions of the disk, some of the molecules in the ice mantles evaporate. It is found that most of the molecules desorbed in this way are transformed into less volatile molecules by the gas-phase reactions, which then freeze out. Molecular abundances both in the gas phase and in ice mantles crucially depend on the temperature and thus vary significantly with the distance from the central star. Although molecular evolution proceeds in protoplanetary disks, our model also shows that significant amount of interstellar ice, especially water ice, survives and is included in ice mantles in the outer region of the disks. We also find that the timescale of molecular evolution is dependent on the ionization rate and the grain size in the disk. If the ionization rate and the grain size are the same as those in molecular clouds, the timescale of the molecular evolution, in which CO and N2 are transformed into other molecules, is about 106 yr, which is slightly smaller than the lifetime of the disk. The timescale for molecular evolution is larger (smaller) in the case of lower (higher) ionization rate or larger (smaller) grain size. We compare our results with the molecular composition of comets, which are considered to be the most primitive bodies in our solar system. The molecular abundances derived from our model naturally explain the coexistence of oxidized ice and reduced ice in the observed comets. Our model also suggests that comets formed in different regions of the disk have different molecular compositions. Finally, we give some predictions for future millimeter-wave and sub-millimeter-wave observations of protoplanetary disks.
Modeling the current-voltage characteristics of bilayer polymer photovoltaic devices

We have developed a numerical model to predict the current-voltage curves of bilayer conjugated polymer photovoltaic devices. The model accounts for charge photogeneration, injection, drift, diffusion, and recombination, and includes the effect of space charge on the electric field within the device. Charge separation at the polymer-polymer interface leads to the formation of bound polaron pairs which may either recombine mono-molecularly or be dissociated into free charges, and we develop expressions for the field dependence of the dissociation rate. We find that the short-circuit quantum efficiency is determined by the competition between polaron pair dissociation and recombination. The model shows a logarithmic dependence of the open-circuit voltage on the incident intensity, as seen experimentally. This additional intensity-dependent voltage arises from the field required to produce a drift current that balances the current due to diffusion of carriers away from the interface.
OPTIMAL TRANSPORTATION OF VECTOR-VALUED MEASURES

Given two n-dimensional measures µ and ν on Polish spaces, we propose an optimal transportation's formulation, inspired by classical Kan-torovitch's formulation in the scalar case. In particular, we established a strong duality result and as a consequence, optimality conditions are investigated. Wasserstein's metrics induced by our formulation are also investigated.
High-energy analysis and Levinson's theorem for the selfadjoint matrix Schrödinger operator on the half line

The matrix Schrodinger equation with a selfadjoint matrix potential is considered on the half line with the general selfadjoint boundary condition at the origin. When the matrix potential is integrable, the high-energy asymptotics are established for the related Jost matrix, the inverse of the Jost matrix, and the scattering matrix. Under the additional assumption that the matrix potential has a first moment, Levinson's theorem is derived, relating the number of bound states to the change in the argument of the determinant of the scattering matrix.
Introduction to reading through animation with children's stories

The intervention of the adult as a mediator with the infant has been widely studied in early childhood, associating an emotional bond of learning through safe communication with the child to promote abilities and skills in different areas, the objective of the study was to identify the Use of children's stories to encourage reading in boys and girls from 12 to 36 months by families. of the initial education centers in the province of Manabí, there is a need to implement strategies that promote the development of language, for this a theoretical framework based on children's stories, reading encouragement, reading routines and language was made, with which an understandable and logical discussion could be established. A field, bibliographical and explanatory investigation with deductive and inductive methods was used, additionally the survey technique applied to 60 members of the parent committee, 74 educators, 60 coordinators of the selected centers, to know aspects relevant to the problems currently faced by boys and girls of these ages, resulting in the need to intervene so that families make use of children's books such as stories to encourage reading in each of the homes of the centers childish.
The Inf-Sup Condition Tests for Shell/Plate Finite Elements / Testy Warunku Inf-Sup Do Oceny Płytowych I Powłokowych Elementów Skonczonych

Abstract Development of high-performance finite elements for thick, moderately thick, as well as thin shells and plates, was one of the active areas of the finite element technology for 40 years, followed by hundreds of publications. A variety of shell elements exist in the FE codes, but “the best” finite element is still to be discovered. The paper deals with an evaluation of some existing shell finite elements, from the point of view of the third of three requirements to be satisfied by the element: ellipticity, consistency and inf-sup condition. It is difficult to prove the inf-sup condition analytically, so, a numerical verification is proposed. A set of numerical tests is considered for shell and plate problems. Two norm matrices and a selection of the stiffness matrices (bending, shear and membrane dominated) are analysed. Finite elements from various computer systems can be evaluated and compared with the use of the proposed tests. Streszczenie Elementy skonczone płyt i powłok powinny spełniac trzy warunki poprawnosci sformułowania: warunek eliptycznosci, warunek zgodnosci i warunek inf-sup. Najtrudniejszy do sprawdzenia jest warunek inf-sup. W pracy rozwinieto i zweryfikowano koncepcje numerycznej weryfikacji tego warunku, zaproponowanej w pracach Bathego i współpracowników. Przedstawiono i zweryfikowano szereg testów płyt o róznych warunkach brzegowych, oraz powłok o róznych krzywiznach Gaussa, w kształcie sfery, walce, paraboloidy hiperbolicznej, stozka i konoidy. Najbardziej wymagajacym testem okazała sie wspornikowa paraboloida hiperboliczna. Zaproponowano i przeanalizowano dwie macierze normowe, bazujace na normie przemieszczen w sensie L2 i semi-normie H1. Wykazano, ze macierz zbudowana na bazie normy L2 jest wystarczajaca do badania warunku inf-sup. Macierz ta jest równowazna macierzy mas elementu skonczonego, przy jednostkowej gestosci materiału, co oznacza ułatwione badania elementów skonczonych w programach komercyjnych. Przedstawiono takze stosownosc wykorzystania pełnej macierzy sztywnosci, oraz macierzy ograniczonych do opisu stanu poprzecznego scinania lub stanu membranowego. Zweryfikowano poprawnosc klasycznych prostokatnych elementów płytowych o liniowych funkcjach kształtu i całkowaniu pełnym lub zredukowanym, oraz elementów powłokowych S4, S4R and S4R5 statemu ABAQUS/Standard.
Convergence rate for eigenvalues of the elastic Neumann--Poincar\'e operator on smooth and real analytic boundaries in two dimensions

The elastic Neumann--Poincar\'e operator is a boundary integral operator associated with the Lam\'e system of linear elasticity. It is known that if the boundary of a planar domain is smooth enough, it has eigenvalues converging to two different points determined by Lam\'e parameters. We show that eigenvalues converge at a polynomial rate on smooth boundaries and the convergence rate is determined by smoothness of the boundary. We also show that they converge at an exponential rate if the boundary of the domain is real analytic.
Multiple Compton scattering by thermal electrons in a spherical inflow: the effects of bulk motion

An analytic steady state solution to the Fokker-Planck equation for Compton scattering in a spherical inflow, where internal monochromatic photons scatter off thermal nonrelativistic electrons undergoing radial bulk motion, is derived. It is found that photon advection by electrons yields an overall reduction in the intensity of the emerging spectrum with increasing velocity. In the case of soft photons emitted close to the trapping surface and small scattering optical depths, the outgoing spectrum is a power law with a slope that depends only on a plasma parameter proportional to the ratio of the Compton time to the infall time. At large values of the optical depth, the spectra show a depletion of high-energy photons being preferentially convected inward and ultimately trapped by the inflowing electrons. If soft radiation is emitted far from the trapping surface, the computed spectra significantly deviate from a power law. The results of these calculations are relevant to the case of supercritical spherical accretion onto black holes. 18 references.
Favaron's Theorem, k-dependence, and Tuza's Conjecture

A vertex set $D$ in a graph $G$ is $k$-dependent if $G[D]$ has maximum degree at most $k-1$, and $k$-dominating if every vertex outside $D$ has at least $k$ neighbors in $D$. Favaron proved that if $D$ is a $k$-dependent set maximizing the quantity $k|D| - |E(G[D])|$, then $D$ is $k$-dominating. We extend this result, showing that such sets satisfy a stronger structural property, and we find a surprising connection between Favaron's theorem and a conjecture of Tuza regarding packing and covering of triangles.
Quantitative mode stability for the wave equation on the Kerr-Newman spacetime

Quantitative versions of mode stability type statements for the wave equation on Kerr-Newman black holes are proven for the full sub-extremal range. The mode stability result on the real axis is then applied to prove integrated local energy decay for solutions restricted to a bounded frequency regime. This is an important element of the proof of unrestricted boundedness and decay statements, presented in a forthcoming companion paper.
Chlamydia abortus Isolation and Identification in Aborted Ovine Fetus in Mari El Republic of Russia

Reproductive disorders, presumably caused by Chlamydia abortus, are common among the ovine population of the Mari El Republic, Russia. C. abortus infection was determined by serologic testing or isolation and detection of the organism by PCR and direct immunofluorescence in tissue samples. Rams, ewes, and lambs (10 individuals each) were randomly chosen for serological testing by the complement fixation test and 7 of 30 (23%) animals tested were positive. Tissue samples were collected from ewes and aborted fetuses for isolation by inoculating chicken embryo yolk sacs (n = 41). The same samples were analyzed by PCR using commercial and in-house PCR kits and by direct immunofluorescence. C. abortus was detected in 58.5% of samples using PCR and in 60.9% of the samples by direct immunofluorescence. Five Chlamydia isolates were cultured in egg yolk sacs and adapted for growth in cell cultures. Phylogenetic analysis showed no substantial difference between Russian isolates and those from other parts of the world. The results of the study further demonstrate the usefulness of PCR for detection of C. abortus as a faster, simpler, and more reliable approach in comparison to culturing the organism and underscoring the necessity of screening for chlamydiosis as a cause of ovine abortion.
Structure, half-metallic and magnetic properties of bulk and (001) surface of Rb2XMoO6 (X = Cr, Sc) double perovskites: a DFT + U study

Half-metallic (HM) ferromagnets (HM-FMs) with large HM gap and high Curie temperature (TC) have a great importance in the field of spintronics. In this study, the geometric features, electronic structure and magnetism of two new double perovskites (DPs) represented by Rb2XMoO6 (X = Cr, Sc) were explored in bulk phase and (001) surface using quantum mechanical total energy calculations based on density functional theory (DFT). The results showed that optimized lattice constant a is 7.96 Å and 8.26 Å for Rb2CrMoO6 (RCMO) and Rb2ScMoO6 (RSMO), respectively, in the cubic phase (space group Fm-3m, #225). The cohesive energy Ecoh, formation energy Efor and elastic constants (mechanical) calculations proved that present materials are stable. The magnetic properties were explored in terms of ground state magnetic coupling, total magnetic moment (M) and atomic magnetic moment (m), exchange energy (J), and Curie temperature. It was found that both materials have ferromagnetic coupling in the ground state, with M of integer value of 8.0 μ B (4.0 μ B), J value of 47 meV(72 meV) and TC of 365 K (557 K) in Rb2CrMoO6 (Rb2ScMoO6). The electronic properties computed with electronic band structure and density of states demonstrated both DPs to be half-metal with HM gap of 1.61 eV (2.1 eV) in Rb2Cr-based (Rb2Sc-based) system. Finally the electronic and magnetic properties of (001) surfaces were investigated and compared with that of bulk phase. Interestingly, bulk HM property was retained in RSMO, but disappeared in RCMO due the emergence of defect states at Fermi level (EF). The reported results suggest that Rb-based DPs carry some fascinating properties for spin-based devices.
Registration using geometry features for augmented reality in soccer

A flexible registration method for augmented reality in soccer based on the field marks is proposed in this paper. By exploiting the geometry relationship among the centre circle, halfway line and the centre mark of the soccer field, the images of the circular points are obtained from the image plane. From the conjugated circular points and the two points of intersection of the halfway line and the centre circle, the homography between the field plane in space and the image plane is calculated. Furthermore, with the constraints that the CCD camera skew is zero and the principle point passes through the image centre, a simple equation is deduced to calculate the intrinsic parameters of the camera. And finally, the camera external parameters are derived from the homography matrix. The registration method is tested using synthetic data and real images. The results show that the method is effective and robust.
MWC 930 – a new luminous blue variable candidate

We present the results of optical high-resolution and near-infrared low-resolution spectroscopy and multicolour optical and near-infrared photometry of the emission-line star MWC 930. The spectrum is rich with Fen emissions, most of which have P Cyg-type profiles. The emission lines are strong and narrow, indicating a powerful stellar wind (M ≥ 1.5 x 10 -6 M ○. yr -1 ) with a low terminal velocity (u∞ ∼ 140 km s -1 ). The photospheric absorption lines are broad and show splitting, which might be due to the object's binarity. MWC 930 is most probably located in the Norma spiral arm at a distance of D = 3-4 kpc. This strong and slow wind as well as the star's luminosity (log L/L ○. ∼ 5.5) and the infrared excess shape suggest that MWC 930 is an unusual B-type supergiant, most likely undergoing the luminous blue variable evolutionary phase.