Miracle-dz/UniFAR-FTUs huggingface dataset:
A prior knowledge based optimal Wiener filtering approach to ultrasonic scattering amplitude estimation

In order to interpret measurements of the scattered wave field resulting from sonification of an object, the effects of the measurement system must be removed from the measured data. In ultrasonic nondestructive evaluation, estimation of the farfield scattering amplitude for a flaw in a material, e.g., a crack, void, or inclusion, involves removing the measurement system effects in the presence of electronic noise and noise due to the scattering of sound from inherent material features such as grain boundaries. The purpose of the work reported here was to evaluate an optimal Wiener filtering approach to scattering amplitude estimation. The filter was shown to determine an optimal estimate as the weighted average of the information derived from measurement of the scattered wave field and prior information about the flaw distribution. The optimal Wiener filter was evaluated and compared to a nonoptimal form of the Wiener filter. The optimal Wiener filter was shown to provide improved scattering amplitude es.
Discovery of the First in-the-Gap SU UMa-Type Dwarf Nova, NY Serpentis (=PG 1510+234)

We performed Photometrie monitoring and time-resolved observations of NY Ser between 1995 July 25 and 1997 March 11. NY Ser shows normal outbursts with a recurrence time of 6-9 days and superoutbursts with a recurrence time of 85-100 days in the range of 14.6-18.0 mag in the V band. The superhump period is 0.106 (±0.001) d, which suggests that the orbital period is located near to the middle of the period gap.
The unsteady structure of two‐dimensional steady laminar separation

The two‐dimensional unsteady incompressible Navier–Stokes equations, solved by a fractional time‐step method, were used to investigate separation due to the application of an adverse pressure gradient to a low‐Reynolds number boundary layer flow. The inviscid pressure distribution of Gaster [AGARD CP 4, 813 (1966)] was applied in the present computations to study the development of a laminar separation bubble. In all cases studied, periodic vortex shedding occurred from the primary separation region. The shed vortices initially lifted from the boundary layer and then returned towards the surface downstream. The shedding frequency nondimensionalized by the momentum thickness was found to be independent of Reynolds number. The value of the nondimensional Strouhal number, however, was found to differ from the results of Pauley et al. [J. Fluid Mech. 220, 397 (1990)], indicating that the shedding frequency varies with the nondimensional pressure distribution, Cp. The computational results were time averaged o.
Magnetic field observations of evolved stars

A search has been made for Zeeman broadening in high resolution spectra of eight G and K type, evolved stars which have active chromospheres and coronae. No Zeeman broadening was found. It is likely that the fraction of the stellar surface that contains magnetic fields is similar in active giants and dwarfs, based on their comparable chromospheric line strengths and plage surface brightnesses (deduced from Mg II/C IV ratios) and on their comparable requirements for coronal confinement. Thus, since Zeeman broadening is detectable on active dwarfs, the nondetections of Zeeman broadening on these evolved stars are probably due to systematically lower field strengths. That the lower field strengths do not result in lower chromospheric surface brightnesses on giants is consistent with the theoretial 'slow mode' MHD wave generation rates of Ulmschneider and Stein (1982). The low field strengths can be explained by requiring that the fields be in equipartition with either the thermal or turbulent energy densities, both of which are reduced in late-type evolved stars compared with the sun.
Modeling a high power fusion plasma reactor-type ion source: Applicability of particle methods

A simple two-dimensional (2D) Cartesian, three-velocities (3 V), particle-in-cell Monte Carlo collisions (PIC MCC) model of a tandem type inductively coupled plasma (ICP) discharge is presented. The conditions are similar to those of negative ion sources for fusion applications, i.e., a high absorbed power (on the order of 100 kW) and a high density plasma (typically 1018 m−3) in a large volume vessel with a magnetic field barrier. We show that the plasma transport properties may be calculated with sufficient accuracy by performing simulations at low plasma density (low absorbed power) and rescaling the results to large plasma density by assuming linear variations of plasma density with power (in case of non-linear plasma chemistry, appropriate scale of the cross-sections or reaction rates is also necessary). This is equivalent to performing the simulations with the real absorbed power but using a larger value of the vacuum permittivity in Poisson’s equation, to force quasineutrality. Rescaled results fro.
Tuning the pitch of a wine glass by playing with the liquid inside

It is well known that the pitch of the sound produced by an excited glass shell can be tuned by adding some liquid in it. In this paper, it will be proved that the distribution of the liquid inside the shell plays a crucial role in this frequency shift. Thus it provides another way to tune the pitch of the sound by modifying the liquid distribution inside the glass. Both adding a cylinder in the liquid or rotating it results in a pitch lowering. A simple model based on energy conservation is in good agreement with the measured experimental results. This paper assumes some basic knowledge about mechanics and hydrodynamics. It addresses instructors of physics at the undergraduate and advanced secondary school level as well as their students.
Emergence of ferromagnetism in antiferromagnetic TbMnO3 by epitaxial strain

We show that in oxide thin films of spiral antiferromagnetic orthorhombic TbMnO3, ferromagnetism emerges resulting from epitaxially induced strain. The unit cell volume can be tuned (contracting up to a 2%) by varying thickness and deposition conditions; it is found that the ferromagnetic response correlates with the unit cell deformation. Such effect of strain on the magnetic properties turns out to be similar to that occurring in collinear orthorhombic antiferromagnets such as YMnO3. Owing to the intimate relationship between magnetic order and ferroelectricity in TbMnO3 these results may provide a new route to induce magnetoelectric coupling and tailor their ferroelectric response.
Manipulation of nanoscale V-pits to optimize internal quantum efficiency of InGaN multiple quantum wells

We systematically investigated the influence of nanoscale V-pits on the internal quantum efficiency (IQE) of InGaN multiple quantum wells (MQWs) by adjusting the underlying superlattices (SLS). The analysis indicated that high barrier energy of sidewall MQWs on V-pits and long diffusion distance between the threading dislocation (TD) center and V-pit boundary were crucial to effectively passivate the non-radiative centers of TDs. For a larger V-pit, the thicker sidewall MQW on V-pit would decrease the barrier energy. On the contrary, a shorter distance between the TD center and V-pit boundary would be observed in a smaller V-pit, which could increase the carrier capturing capability of TDs. An optimized V-pit size of approximately 200–250 nm in our experiment could be concluded for MQWs with 15 pairs SLS, which exhibited an IQE value of 70%.
Extensions of the big Picard's theorem

THEOREM A. Let Mbe a complex manifold, S a regular thin analytic subset of M and f a holomorphic map of M — S into the N-dimensίonal complex protective space PN(C). Iff is of rank r somewhere and iff(M-S) omits 2N — r + 2 hyperplanes in general position, then f can be extended to a holomorphic map of M into PN(C), where the rank of f at a point xe M — S means the rank of the Jacobian matrix of f at x.
The planetary nebula in the Fornax dwarf galaxy

S OF CONTRIBUTED PAPERS THE PLANETARY NEBULA IN THE FORNAX DWARF GALAXY I.J. Danziger*, M. Dopita**, T.G. Hawarden***, B.L. Webster* *Anglo-Australian Observatory, Epping, N.S. W. , Australia **Mt. Stromlo and Siding Spring Observatory, Canberra, A.C. T. , Australia ***U.K. Schmidt Telescope Unit, Royal Observatory, Edinburgh A planetary nebula has been identified near the center of the Fornax dwarf elliptical galaxy. Quantitative spectrophotometry reveals that it is slightly reddened, and belongs to an intermediate-excitation class, with a normal helium abundance. Since the abundances of all 2 to 3 times lower than in the Orion nebula, the material in the nebula which has a mass >_ 0.1 M@ probably represents at least a second generation of processed matter. The implications of this conclusion are briefly discussed from the point of view of heavy element enrichment in low mass systems such as Fornax whose mass is 2xl07 M@. (Paper will appear in The Astrophysical Journal.)
Quantum Ising quasi-crystal

A quantum Ising spin chain with two-valued nearest-neighbour couplings arranged in a quasi-periodic sequence is considered, in the presence of a uniform transverse field. The scaling properties of the energy spectrum of the model are analytically determined. The system can undergo a phase transition both when the two couplings have equal sign (ferro- or antiferromagnetic couplings) and when they have opposite sign (frustrated system). The critical point is explicitly obtained; the critical behaviour is shown to be the same as in the periodic case.
Envelope solitons of the giant pulsations (Pg)

Using the data of the observations at auroral observatory Molodezhnaya (Antarctic,L = 6.3), a similarity is found in the shape of the wave packets amplitudes envelope ofgiant pulsations to solitons. The relation is analyzed between the maximum amplitude (A),the carrier in frequency (f), and the width of wave packets (τ) for 30 cases of observationsof the Pg pulsations having the form of separated wave packets. It is shown that themaximum amplitude of wave packets depends linearly on 1/τ√f. We suggest that some Pgpulsations present nonlinear structures having the properties of solutions.
EDS code for new Keynesian model with ZLB in "Merging Simulation and Projection Aproaches to Solve High-Dimensional Problems with an Application to a New Keynesian model"

We introduce an algorithm for solving dynamic economic models that merges stochastic simulation and projection approaches: we use simulation to approximate the ergodic measure of the solution, we construct a fixed grid covering the support of the constructed ergodic measure, and we use projection techniques to accurately solve the model on that grid. The grid construction is the key novel piece of our analysis: we select an e-distinguishable subset of simulated points that covers the support of the ergodic measure roughly uniformly. The proposed algorithm is tractable in problems with high dimensionality (hundreds of state variables) on a desktop computer. As an illustration, we solve one- and multicountry neoclassical growth models and a large-scale new Keynesian model with a zero lower bound on nominal interest rates. (This abstract was borrowed from another version of this item.)
Surface superconductivity in 3 dimensions

We study the Ginzburg-Landau system for a superconductor occupying a 3-dimensional bounded domain, and improve the estimate of the upper critical field H C3 obtained by K. Lu and X. Pan in J. Diff. Eqns. , 168 (2000). 386-452. We also analyze the behavior of the order parameters. We show that, under an applied magnetic field lying below and not far from H C3 order parameters concentrate in a vicinity of a sheath of the surface that is tangential to the applied field, and exponentially decay both in the normal and tangential directions away from the sheath in the L 2 sense. As the applied field decreases further but keeps in between and away from H C2 and H C3 , the superconducting sheath expands but does not cover the entire surface, and superconductivity at the surface portion orthogonal to the applied field is always very weak. This phenomenon is significantly different to the surface superconductivity on a cylinder of infinite height studied by X. Pan in Comm. Math. Phys., 228 (2002), 327-370, where under an axial applied field lying in-between H C2 and H C3 the entire surface is in the superconducting state.
Experimental Studies and Correlations of Radially Outward and Inward Air-Flow Heat Transfer in a Rotating Square Duct

Experiments were conducted to investigate the convective heat transfer of radially outward and inward air flows in a uniformly heated rotating square duct. The interior duct surfaces, constructed byfiberglass-reinforced plastic, were plated with separated film heaters for distinguishing the local wall heat transfer rate. The duct hydraulic diameter, the actively heated length, and the mean rotation radius are 4, 120, and 180 mm, respectively. In the experiments, the parameters were the throughflow Reynolds number, Re = 1,000 ∼15,000 ; the rotation number, Ro = 0∼0.32 ; and the rotational buoyancy parameter, Ra * = 0∼0.5. For the outward flow the Coriolis-induced crossstream secondary flow strongly enhanced the heat transfer on the leading edge. But for the radially inward flow the trend was reversed. When the throughflow Reynolds number was increased, the rotating-buoyancy decreased, then increased the heat transfer for the outward flow ; however, the rotating-buoyancy always increased the heat transfer for the inward flow. The heat transfer data are correlated for the outward and inward flows for the ranges of parameters under study.
Design and Implementation of a Low-Cost Scalar Multiplier-on-Chip for Elliptic Curve Cryptosystem

In the ECC, scalar multiplication represents the core operation of the system. In recent years, the circuit architecture of triple processor cores or greater has been addressed in the domestic and international literature. A parallel processing concept is mainly used in this type of framework to accelerate circuit operation. In the present study, equation calculation and circuit design were employed to integrate the pipeline architecture and the parallel processing architecture and further propose an elliptic curve scalar multiplier for dual processor cores. In addition, a Xilinx XC5VLX110T FPGA was used to verify the accuracy and performance of circuit functions. The maximum frequency was 173 MHz, the number of LUTs was 14999 slices, and the time to accomplishing one scalar multiplication was only 8.8s. Compared to architectures described in recent reports, the architecture presented was faster and effectively reduced the square measure by 28%.
Intensity and Duration of Noise Exposure and Temporary Threshold Shifts

What is the “trading relationship” between intensity and duration of exposures to loud sound in producing a given magnitude of temporary threshold shift (TTS)? Examination of the literature led to the hypothesis that duration is about twice as important as intensity: Two exposures should produce the same TTS if one exposure were one‐fourth the sound level (6 db less) and twice the duration of the other exposure. The hypothesis was tested on 12 human ears with thermal noise exposures ranging from 130 db SPL for 1 min to 94 db SPL for 64 min. In this series each doubling of duration was associated with a fourfold or 6 db decrease in sound level. TTS was measured at 2000, 4000, 6000, and 8000 cps. If the hypothesis were true, all exposures should have produced the same TTS. Actually the obtained average TTS, 5 min after exposure, described an inverted U‐shaped function when plotted by increasing duration of exposure. The conditions from 118 db for 4 min through 100 db for 32 min produced roughly similar amou.
Logarithmic Kinetics of the Amorphous-Amorphous Transformations in SiO 2 and GeO 2 Glasses under High Pressure

We have studied in situ the kinetics of the amorphous-amorphous coordination transformation in ${\mathrm{GeO}}_{2}$ glass and of the initial stage of transformation in vitreous ${\mathrm{SiO}}_{2}$ up to 9 GPa by volume vs time measurements using the precise strain-gauge technique. The volume vs time dependence at all pressure points was found to obey the logarithmic law, which distinguishes the observed transformation kinetics from that of the ordinary transitions in crystals. The first evidence of anelastic behavior was found from the quasistatic equation of state at $P\ensuremath{\approx}6\char21{}7$ GPa for ${\mathrm{SiO}}_{2}$ glass and at 2\char21{}3 GPa for ${\mathrm{GeO}}_{2}$ glass, i.e., at lower pressures than previously believed.
The folded protein as a viscoelastic solid

We apply a nanorheology technique to explore the mechanical properties of a globular protein in the frequency range 10 Hz–10 kHz and find that the folded state of the protein behaves like a viscoelastic solid. For increasing amplitude of the forcing, we observe three different regimes: linear elasticity, then a regime of viscoelastic but reversible deformations, and finally an irreversible regime. The second regime, which has the signature of a viscoelastic solid, gives access to the internal dissipation coefficient of the folded state, for which we find γ≈4×10− 5 kg/s, corresponding to an internal viscosity η∼104 Pa·s for frequencies below ∼10 Hz. We propose that the large discrepancy between this value, which agrees with previous AFM indentation experiments, and the value of the internal viscosity extracted from refolding experiments is a consequence of the viscoelastic nature of the protein's mechanics. Thus the present method yields detailed measurements of the mechanics of the folded state.
On the Dynamics of

We investigate the global stability, the periodic character and the boundedness nature of solutions of the equation in the title for all admissible nonnegative values of the parameters and the initial conditions. We show that the solutions exhibit a trichotomy character depending on how the parameter γ compares to the sum of the parameters δ and A.
Value Iteration in a Class of Communicating Markov Decision Chains with the Average Cost Criterion

Markov decision processes with denumerable state space and discrete time parameter are considered. The performance index of a control policy is the (lim sup expected) average cost criterion, and the the main structural restrictions on the model are the following: (i) under the action of any stationary policy, the state space is a communicating class; (ii) the cost function has an almost monotone---or penalized---structure [V. S. Borkar, SIAM J. Control Optim. }, 21 (1983), pp. 652--666; 22 (1984), pp. 965--978]; and (iii) some stationary policy induces an ergodic chain with finite average cost. In this context it is shown that the value iteration scheme can be used to construct convergent approximations of a solution to the optimality equation, as well as a sequence of stationary policies whose limit points are optimal.
Split-and-merge Procedure for Image Segmentation using Bimodality Detection Approach

Image segmentation, the division of a multi-dimensional image into groups of associated pixels, is an essential step for many advanced imaging applications. Image segmentation can be performed by recursively splitting the whole image or by merging together a large number of minute regions until a specified condition is satisfied. The split-and-merge procedure of image segmentation takes an intermediate level in an image description as the starting cutest, and thereby achieves a compromise between merging small primitive regions and recursively splitting the whole images to reach the desired final cutest. The proposed segmentation approach is a split-andmerge technique. The conventional split-and-merge algorithm is lacking in adaptability to the image semantics because of its stiff quadtree-based structure. In this paper, an automatic thresholding technique based on bimodality detection approach with non-homogeneity criterion is employed in the splitting phase of the split-and-merge segmentation scheme to directly reflect the image semantics to the image segmentation results. Since the proposed splitting technique depends upon homogeneity factor, some of the split regions may or may not split properly. There should be rechecking through merging technique between the two adjacent regions to overcome the drawback of the splitting technique. A sequential-arrange-based or a minimal spanning-tree based approach, that depends on data dimensionality of the weighted centroids of all split regions for finding the pair wise adjacent regions, is introduced. Finally, to overcome the problems caused by the splitting technique, a novel merging technique based on the density ratio of the adjacent pair regions is proposed. The algorithm has been tested on several synthetic as well as real life data and the results show the efficiency of the segmentation technique. Defence Science Journal, 2010, 60(3), pp.290-301 , DOI:http://dx.doi. org/10.14429/dsj.60. 356
Optimal intermittent search strategies

We study the search kinetics of a single fixed target by a set of searchers performing an intermittent random walk, jumping between different internal states. Exploiting concepts of multi-state and continuous-time random walks we have calculated the survival probability of a target up to time t, and have ‘optimized’ (minimized) it with regard to the transition probability among internal states. Our model shows that intermittent strategies always improve target detection, even for simple diffusion states of motion.
Stable periodic solutions to discrete and continuum arrays of weakly coupled nonlinear oscillators

The existence and stability of periodic solutions to spatially distributed arrays of neural oscillators is analyzed. Conditions are found that guarantee that phase-locked patterns are orbitally stable. These conditions allow the solutions to be extended as some parameter varies. For continuum arrays with some differentiability conditions, it is shown that locking is lost when certain phase gradients become unbounded. Numerical methods are used to show that the results apply to realistic synaptically coupled oscillating neural networks. In particular, it is shown that synchronized solutions cannot generally be expected even if the neurons are identical.
Stiff systems of ordinary differential equations

Abstract Solutions of the stiff system of linear differential equations are obtained in a form yielding tight estimates of their properties, and conditions are obtained under which the operator norm of the map from r to the solution x does not become exponentially large for small values of ε. When these conditions are satisfied, the solutions are shown to be close to those of Ax + r = 0, save at any singular points of A, and in boundary layers. The behaviour of solutions near admissible singular points is also obtained. The results are used to characterize those boundary-value problems for the above system in which the solution defines maps from the data that are of “moderate” operator norm. This leads to a constructive existence theory for a limited class of boundary-value problems for the nonlinear system It is suggested that the treatment of more general classes of boundary-value problems may be simplified using these results. By the use of simple examples, the problems involving large operator norms are shown to be related to the stability properties of the possible branches of the outer solutions close to those of
Augmented Lyapunov functional and delay‐dependent stability criteria for neutral systems

In this paper, an augmented Lyapunov functional is proposed to investigate the asymptotic stability of neutral systems. Two methods with or without decoupling the Lyapunov matrices and system matrices are developed and shown to be equivalent to each other. The resulting delay‐dependent stability criteria are less conservative than the existing ones owing to the augmented Lyapunov functional and the introduction of free‐weighting matrices. The delay‐independent criteria are obtained as an easy corollary. Numerical examples are given to demonstrate the effectiveness and less conservativeness of the proposed methods. Copyright © 2005 John Wiley & Sons, Ltd.