Miracle-dz/UniFAR-FTUs huggingface dataset:
Three-Body Scattering and Hail Size

Abstract The three-body scattering signature is an appendage seen on weather radar displays of reflectivity behind strong storm cells. It is caused by multiple scattering between hydrometeors and the ground. The radar equation for this phenomenon is reexamined and corrected to include the coherent wave component producing 3 dB more power than previously reported. Furthermore, the possibility to gauge hail size causing this phenomenon is explored. A model of forward scattering by spherical hail and accepted values of ground backscattering cross sections are used in an attempt to reconcile the reflectivity in this signature with observations. This work demonstrates that the signature can be caused by small- (<10 mm) to moderate- (20 mm) sized hail. An effort to gauge hail size by comparing the direct return from hail with the three-body scattered return is made. The theory indicates fundamental ambiguities in size retrieval resulting from resonant effects. Although theory eliminates the number of hailstones.
Cosmic ray momentum diffusion in the presence of nonlinear Alfvén waves

Abstract. The relation between the spatial diffusion coefficient along the magnetic field, k II , and the momentum diffusion coefficient, D p , for relativistic cosmic ray particles is modelled using Monte Carlo simulations. Wave fields with vanishing wave helicity and cross-helicity, constructed by superposing 'Alfven-like' waves are considered. As the result, particle trajectories in high amplitude wave fields and then - by averaging over these trajectories - the values of transport coefficients are derived. The modelling is performed at various wave amplitudes, from δ B / B 0 = 0.15 to 2.0, and for a number of wave field types. At our small amplitudes approximately the quasi-linear theory (QLT) estimates for k II and D p are reproduced. However, with growing wave amplitude the simulated results show a small divergence from the QLT ones, with k II decreasing slower than theoretical prediction and the opposite being true for D p . The wave field form gives only a slight influence on the wave-particle interactions at large wave amplitudes δ B / B 0 ~ 1. The parameter characterizing the relative efficiency of the second-order to the first-order acceleration at shock waves, D p κ II is given in the QLT approximation by the Skilling formula V 2 A p 2 / 9. In simulations together with increasing δ B it increases above this scale in all the cases under our study. Consequences of the present results for the second-order Fermi acceleration at shock waves are briefly addressed.
Large-amplitude variables near the Galactic Centre

We report here the results of a 4-yr K-band (2.2 μm) survey for large-amplitude variable stars in a area centred on the Galactic Centre. A total of 409 likely long-period variables (LPVs) were detected, for which positions, amplitudes, average magnitudes and periods were obtained whenever possible. The surface density of LPVs is more than ten times greater than in the Sgr I Baade window at The limits of completeness arising from interstellar and circumstellar absorption are discussed. Most of the area suffers interstellar extinction of The shorter-period LPVs are less luminous than the longer-period ones and may be slightly under-represented in the data. Extremely heavy extinction which affects the probability of detecting variables, occurs in less than 25 per cent of the area. Almost all of the LPVs are Miras or OH/IR stars, with periods ranging from 150 d to about 800 d. K-band counterparts have been found for 59 per cent of the 109 known OH sources in the field. The average period of the variables found is 427 d, while that of the OH/IR stars is 524 d. For comparison, the average period in the Sgr I window, which contains no known OH/IR stars, is 333 d and only two stars are detected with The survey field also contains a number of long-period, large-amplitude variables that are not OH emitters.
TX Cancri, the golden wonder

Spectrososopic, photometric, and polarimetric observations of TX Cancri, a W UMa-type binary system in Praesepe, are reported. The parameters (masses, radii, luminosities) of the components of the system are determined. If the system is evolved, then it must have last a substantial amount of mass to reach its present state. We argue that TX Cnc is unevolved, and an age-zero contact- binary model for the system is constructed. Problems in the interpretation of the parameters of the system and the age-zero model are discussed.
Core‐collapse supernovae and their massive progenitors

In this summary of the 10 November 2006 RAS Specialist Discussion Meeting, organizers Paul Crowther and Steve Smartt consider aspects of massive stellar evolution, their dependence upon stellar winds, progenitor models and explosion mechanisms. In addition, observations of core-collapse supernovae were discussed alongside the question of whether supernovae form significant quantities of dust, of relevance to the detection of dust in star-forming galaxies in the early universe.
On the zeros of polynomials with complex coefficients

1. Introduction. Problems in dynamics very frequently have physically realizable solutions only if the determinantal equation of the system has all its roots in the negative half of the complex plane. It is therefore convenient to have a simple algorithm for testing whether this condition holds without actually computing the roots. Solutions to this problem have been considered by Cauchy [l], 2 Routh [ó], and many others. Hurwitz [4] gave a method for polynomials with real coefficients of the form
Fast PolSAR Data Visualization and Classification Based on Huynen Canonical Decomposition

A scattering degree of preference parameter is developed from Huynen canonical dichotomy which displays superior classification ability over the scattering similarity parameter. A scattering hue parameter is then proposed and demonstrated to be of superiority compared with scattering alpha on description of scattering mechanism. A scattering saturation parameter is further defined and shows comparable to scattering entropy on description of scattering randomness. A Huynen dichotomy-based PolSAR data visualization scheme is finally obtained which not only works more efficient but also makes the results look better than that from H/alpha
How Can We Create Safe Smart Cities? A Qualitative Analysis from Multiple Stakeholders’ Perspective

A ‘smart city’ refers to various information technology solutions to make city a better place to live and work. Nevertheless, such technological advances are also rapidly changing public decision-making and functioning of societies, bringing both benefits and threats. The paradox of increasing efficiency and, at the same time, increasing potential harm to citizens occurs particularly in the domain of smart city safety solutions. This paper explores the tensions of decision-makers and implementers of smart city safety technologies (e.g., government and municipality officials, law enforcement, businesses, and academics) and investigate the main success factors, benefits, and risks that these actors see in creating a safe smart city. We conducted seven focus groups with diverse stakeholders to investigate the present and future of smart cities. Our findings contribute to better understand what a safe smart city means and how policy makers and companies can work together to make it happen.
SIMULTANEOUS X-RAY, UV, AND OPTICAL OBSERVATIONS OF THE RECENT NOVA HR DEL.

HR Del was observed simultaneously with the IUE satellite (low-dispersion spectroscopy), the DAO 1.8-m telescope (medium-dispersion spectroscopy), and the Einstein observatory (X-ray imaging proportional counter) over part or all of one 4-hour orbital cycle. The orbital ephemeris is refined and accurate phases computed for the data. The UV spectra show changes in the C IV P Cygni profile which suggest a spiralling stellar wind. A considerable overabundance of C and N in the wind is indicated. The UV data are also used to determine the continuum flux and temperature, and its variability. Optical spectroscopy shows some small changes since 1978 and confirms the strength of C features in the accretion disk. The X-ray observations yield a marginal detection, indicating a luminosity of 2 x 10 to the 31st erg/sec in the 0.5-3 keV flux. New estimates of the reddening and luminosity are derived.
An Application of Nonlocal External Conditions to Viscous Flow Computations

We are looking for a steady-state solution of an external flow problem originally formulated on an unbounded domain. Our case is a 2D viscous compressible flow past a finite body (airfoil). We truncate the original domain by introducing a finite grid around the airfoil and integrate the Navier-Stokes equations on this grid with the help of a finite-volume code which involves a multigrid pseudo-time iteration technique for achieving a steady state. To integrate the Navier? Stokes equations on a finite subregion of an original domain only we supplement the numerical algorithm by special nonlocal artificial boundary conditions formulated on an external boundary of the finite computational domain. These artificial boundary conditions are based on the difference potentials method proposed by V. S. Ryaben'kii. We compare the results provided by the nonlocal conditions with those obtained from the standard external conditions which are based on locally one-dimensional characteristic analysis at inflow and extrapolation at outflow. It turns out that the nonlocal artificial boundary conditions accelerate the convergence by about a factor of 3, as well as allow one to shrink substantially the computational domain without loss of accuracy.
On the Optimization of Raman Fiber Amplifier using Genetic Algorithm in the Scenario of a 64 nm 320 Channels Dense Wavelength Division Multiplexed System

For multi parameter optimization of Raman Fiber Amplifier (RFA), a simple genetic algorithm is presented in the scenario of a 320 channel Dense Wavelength Division Multiplexed (DWDM) system at channel spacing of 25 GHz. The large average gain (> 22 dB) is observed from optimized RFA with the optimized parameters, such as 39.6 km of Raman length with counter-propagating pumps tuned to 205.5 THz and 211.9 THz at pump powers of 234.3 mW, 677.1 mW respectively. The gain flattening filter (GFF) has also been optimized to further reduce the gain ripple across the frequency range from 190 to 197.975 THz for broadband amplification.
Trapping of water waves by freely floating structures in a channel

This article is concerned with the existence of rigid freely floating structures capable of supporting trapped modes (time-harmonic water waves of finite energy in an unbounded domain). Under the usual assumptions of linear water-wave theory, a condition guaranteeing the existence of trapped modes is derived, and structures satisfying this geometric condition are shown to exist in a three-dimensional water channel. The sufficient condition arises from the application of variational principles to a conveniently formulated linear spectral problem, the main effort being the construction of a reduction scheme that turns the quadnic operator pencil associated with the original coupled system into a linear self-adjoint spectral problem. An example of floating bodies supporting at least four trapped modes is given.
An Analysis of the Confusion among English Consonants Heard in the Presence of Random Noise

The English consonants p, t, k, f, θ (thin), s, ∫ (she), b, d, g, v, ð (they), z, ȝ (beige), m and n were pronounced before the vowel a (father) by female talkers with General American pronunciation. Listeners heard the syllables in the presence of a masking noise and were forced to guess at every syllable. The signal‐to‐noise ratio, measured between the over‐all level of the noise in a band from 20 to 7000 cps and the level of the vowel as read on a VU meter, ranged from −18 to +12 db in steps of 6 db. Five talkers were used with four listeners for each talker. The most obvious aspect of these consonants in noise is the presence or absence of voicing; voiced and voiceless consonants were seldom confused until S/N was about −12 db or worse. The aspect of nasality also seems to disappear at about −12 db. The next most obvious aspect is the difference between stops and continuants; confusions on this aspect did not occur until S/N was about −6 db or worse. These three aspects define five classes of consonan.
Improvements of the Maximum Pseudo-Likelihood Estimators in Various Spatial Statistical Models

Abstract Maximum pseudo-likelihood estimation has hitherto been viewed as a practical but flawed alternative to maximum likelihood estimation, necessary because the maximum likelihood estimator is too hard to compute, but flawed because of its inefficiency when the spatial interactions are strong. We demonstrate that a single Newton-Raphson step starting from the maximum pseudo-likelihood estimator produces an estimator which is close to the maximum likelihood estimator in terms of its actual value, attained likelihood, and efficiency, even in the presence of strong interactions. This hybrid technique greatly increases the practical applicability of pseudo-likelihood-based estimation. Additionally, in the case of the spatial point processes, we propose a proper maximum pseudo-likelihood estimator which is different from the conventional one. The proper maximum pseudo-likelihood estimator clearly shows better performance than the conventional one does when the spatial interactions are strong.
A Bayesian Analysis of a Poisson Random Effects Model for Home Run Hitters

Abstract The problem of interest is to estimate the home run ability of 12 great major league players. The usual career home run statistics are the total number of home runs hit and the overall rate at which the players hit them. The observed rate provides a point estimate for a player's “true” rate of hitting a home run. However, this point estimate is incomplete in that it ignores sampling errors, it includes seasons where the player has unusually good or poor performances, and it ignores the general pattern of performance of a player over his career. The observed rate statistic also does not distinguish between the peak and career performance of a given player. Given the random effects model of West (1985), one can detect aberrant seasons and estimate parameters of interest by the inspection of various posterior distributions. Posterior moments of interest are easily computed by the application of the Gibbs sampling algorithm (Gelfand and Smith 1990). A player's career performance is modeled using a lo.
Stochastic adaptive control and prediction--The general delay-colored noise case

Recent papers have established global convergence for stochastic adaptive control and prediction algorithms for discrete time linear systems. The general delay-white noise case and the unit delay-colored noise case have been treated. This paper extends the results to the general delay-colored noise case. Also, a slightly different proof technique is used which relies only upon elementary analysis and is thus of pedagogical interest.
Some odds ratio statistics for the analysis of ordered categorical data

SUMMARY Snell (1 964) has proposed a general regression model for the analysis of ordered categorical data which is based upon an extension of the log odds transformation. With this model, some simple odds ratio statistics are developed to summarize the difference in location between two distributions of an ordered categorical variable. Similar statistics for describing association between two such variables are also discussed.
Cloud Feedback Processes in a General Circulation Model

Abstract The influence of the cloud feedback process upon the sensitivity of climate is investigated by comparing the behavior of two versions of a climate model with predicted and prescribed cloud cover. The model used for this study is a general circulation model of the atmosphere coupled with a mixed layer model of the oceans. The sensitivity of each version of the model is inferred from the equilibrium response of the model to a doubling of the atmospheric concentration of carbon dioxide. It is found that the cloud feedback process in the present model enhances the sensitivity of the model climate. In response to the increase of atmospheric carbon dioxide, cloudiness increases around the tropopause and is reduced in the upper troposphere, thereby raising the height of the cloud layer in the upper troposphere. This rise of the high cloud layer implies a reduction of the temperature of the cloud top and, accordingly, of the upward terrestrial radiation from the top of the model atmosphere. Thus, the hea.
Bubble Nucleation on Micro Line Heaters

Nucleation temperatures on the micro line heaters were measured precisely by obtaining the I-R (current-resistance) characteristic curves of the heaters. The bubble nucleation temperatures on the heater with 3 μm width are higher than the superheat limit, while the temperature on the heater with broader width of 5 μm are considerably less than the superheat limit. The nucleation temperatures were also estimated by using the molecular cluster model of bubble nucleation with effect of contact angle. The bubble nucleation process was observed by microscope / 35 mm camera unit with a flash light of μs duration.
Document Clustering Based on Fuzzy Similarity

This paper proposes a novel fuzzy similarity measure based on the relationships between terms and categories. A term-category matrix is presented to represent such relationships and each element in the matrix denotes a membership degree that a term belongs to a category, which is computed using term frequency inverse document frequency and fuzzy relationships between documents and categories. Fuzzy similarity takes into account the situation that one document belongs to multiple categories and is computed using fuzzy operators. The experimental results show that the proposed fuzzy similarity surpasses other common similarity measures not only in the reliable derivation of document clustering results, but also in document clustering accuracies.
Modeling tree effects on path loss in a residential environment

A theoretical model is proposed to compute the path loss in a vegetated residential environment, with particular application to mobile radio systems. As in the past, rows of houses or blocks of buildings are viewed as diffracting cylinders lying on the Earth and the canopy of the trees is located adjacent to and above the houses/buildings. In this approach, a row of houses or buildings is represented by an absorbing screen and the adjacent canopy of trees by a partially absorbing phase screen. The phase-screen properties are found by finding the mean field in the canopy of the tree. Physical optics (PO) is then used to evaluate the diffracting field at the receiver level by using a multiple Kirchhoff-Huygens integration for each absorbing/phase half-screen combination.
Huber-based novel robust unscented Kalman filter

This study concerns the unscented Kalman filter (UKF) for the non-linear dynamic systems with error statistics following non-Gaussian probability distributions. A novel robust unscented Kalman filter (NRUKF) is proposed. In the NRUKF the measurement information (measurements or measurements noise) is reformulated using Huber cost function, then the standard unscented transformation (UT) is applied to exact non-linear measurement equation. Compared with the conventional Huber-based unscented Kalman filter (HUKF) which is derived by applying the Huber technique to modify the measurement update equations of the standard UKF, the NRUKF, without linear (statistical linear) approximation, has much-improved performance and versatility with maintaining the robustness. Then the NRUKF is applied to the target tracking problem. The validity of the algorithm is demonstrated through numerical simulation study.
The Forward Tagger facility for low Q2 experiments at Jefferson Laboratory

Low Q 2 electron scattering is an efficient and competitive experimental technique to provide intense, quasi-real photon beams, with a high degree of linear polarization. Such a technique will be employed in Hall B at Jefferson Laboratory by having the primary 11 GeV electron beam from the CEBAF accelerator impinging on a liquid hydrogen target. Low-angle scattered electrons will be detected with the new Forward Tagger facility, while the final state hadrons will be measured with the CLAS12 spectrometer. The unique combination of the two detectors will permit to carry out a broad physics program, and to explore new possibilities for high quality physics.
A Technique for Estimating Linear Parameters Using Nonlinear Restoring Force Extraction in the Absence of an Input Measurement

Conventional nonlinear system identification procedures estimate the system parameters in nvo stages. First, the nominally linear system parameters are estimated by exciting the system at an amplitude (usually low) where the behavior is nominally linear. Second, the nominally linear parameters are used to estimate the nonlinear parameters of the system at other arbitrary amplitudes. This approach is not suitable for many mechanical systems, which are not nominally linear over a broad frequency range for any operating amplitude. A method for nonlinear system identification, in the absence of an input measurement, is presented that uses information about the nonlinear elements of the system to estimate the underlying linear parameters. Restoring force, boundary perturbation, and direct parameter estimation techniques are combined to develop this approach. The approach is applied to experimental tire-vehicle suspension system data.
Hydromagnetic free shear layers in rotating flows with magnetic field perpendicular to rotation vector and shear layers

Following Hollerbach's work (1996) hydromagnetic free shear layers are analyzed when the applied magnetic field is perpendicular to both the rotation vector and vertical free shear layers. Analytical solutions have been obtained for the shear layer and interior regions. The physical features of the flow are discussed with special emphasis on meridional flow of electric current flux.
Efficient Second-Harmonic Generation of 340-nm Light in a 1.4-µm Periodically Poled Bulk MgO:LiNbO3

Ultra-violet second-harmonic generation in a 1.4 µm periodically poled MgO:LiNbO3 is presented. Using a high-voltage multi-pulse application method, a first-order nonlinear grating with a period of 1.4 µm was fabricated over 10-mm interaction length in a 2-mm thick MgO:LiNbO3 substrate. In a single pass configuration, cw 1.2 mW of ultraviolet light at 341.5 nm was successfully obtained for a fundamental power of 141 mW, corresponding to a normalized conversion efficiency of 5.4%/W.
Boolean methods for double integration

This paper is concerned with numerical integration of continuous functions over the unit square U . The concept of the rth-order blending rectangle rule is introduced by carrying over the idea from Boolean interpolation. Error bounds are developed, and it is shown that rth-order blending rectangle rules are comparable with number-theoretic cubature rules. Moreover, rth-order blending midpoint rules are defined and compared with the rth-order blending rectangle rules.