Miracle-dz/UniFAR-FTUs huggingface dataset:
Evidence that wind prediction with multiple guide stars reduces tomographic errors and expands MOAO field of regard

We explore the extension of predictive control techniques to multi-guide star, multi-layer tomographic wavefront measurement systems using a shift-and-average correction scheme that incorporates wind velocity and direction. In addition to reducing temporal error budget terms, there are potentially additional benefits for tomographic AO systems; the combination of wind velocity information and phase height information from multiple guide stars breaks inherent degeneracies in volumetric tomographic reconstruction, producing a reduction in the geometric tomographic error. In a tomographic simulation of an 8-meter telescope with 3 laser guide stars over 2 arcminute diameter, we find that tracking organized wind motion as it flows into metapupil regions sampled by only one guide star improves layer estimates beyond the guide star radius, allowing for an expansion of the field of view. For this case, we demonstrate improvement of layer phase estimates of 3% to 12%, translating into potential gains in the MOAO field of regard area of up to 40%. The majority of the benefits occur in regions of the metapupil sampled by only 1-2 LGS's downwind at high altitudes.
The Research of Multi-point Function Opaque Predicates Obfuscation Algorithm

On the algorithm of code obfuscation, opaque predicate is used to confuse the judgment of the program branches to achieve complex control flow statement. Currently, there are problems o f obfuscation on the opaque predicate. The first problem is the isolation. the relation between opaque predicate is relatively isolated, onc e an opaque predicates Boolean value is obtained, the branch flow will always be identified; Second is the reversible, an attacke r can determine the opaque predicate the Boolean value by analyzing reversible slicing attacks. In this paper, we proposed multi-poin t function opaque predicate obfuscation algorithm, using multi-function features makes opaque predicates interdependent and avoid reversible slicing attacks. Experimental data demonstrates that the obfuscated program performance and security has been significantly improved.
CN column densities and excitation temperatures

We analyse abundances and rotational temperatures of the interstellar CN molecule. We have calculated the column densities and excitation temperatures of the molecule along 73 lines of sight basing on our original measurements of the B 2 Σ + - X 2 Σ + (0,0) vibrational band recorded in high signal-to-noise ratio spectra and also for 88 directions based on measurements already available in literature. We compare the column densities obtained from different bands of CN molecule available to ground-based instruments. The obtained excitation temperatures in the analysed directions show always an excess over the cosmic microwave background radiation (CMBR) temperature.
Rayleigh-Taylor Instabilities of a Collapsing Cylindrical Shell in a Magnetic Field

The instability of a radially accelerated cylindrical shell in a magnetic field has been investigated. It was assumed that the shell was of infinitesimal thickness. For perturbations which do not bend the lines of the magnetic field, the growth rate was found to be w = (gk)½, where g is the acceleration of the shell and k is the wavenumber. This growth rate is independent of the shell thickness. Perturbations which do bend the lines of the field were also found to be unstable. From a supplementary calculation, it was concluded that these instabilities were effective only for wavelengths greater than 8πa where 2a is the shell thickness.
A Nonparametric Method for Dealing with Mismeasured Covariate Data

Abstract Mismeasurement of covariate data is a frequent problem in statistical data analysis. However, when true and mismeasured data are obtained for a subsample of the observations, it is possible to estimate the parameters relating the outcome to the covariate of interest. Maximum likelihood methods that rely on parametric models for the mismeasurement have not met with much success. Realistic models for the mismeasurement process are difficult to construct; the form of the likelihood is often intractable and, more important, such methods are not robust to model misspecification. We propose an easily implemented method that is nonparametric with respect to the mismeasurement process and that is applicable when mismeasurement is due to the problem of missing data, errors in variables, or use of imperfect surrogate covariates. Specifically, denote the outcome variable by Y, the covariate data subject to mismeasurement by X, and the remaining covariates, including perhaps surrogates or mismeasured values .
Lens design with planar 1D photonic crystal

An aspheric collimating slab waveguide lens is designed using a diverging planar 1-D photonic crystal. An approximation method for analysis of such structures has been developed. A lens design procedure (which minimizes area) is also introduced. For illustration purposes, we use Silicon on insulator technology with the minimum feature size of 100 nm. We show that fast lens with 130 μm focal length, f/# = 1.3 is achievable with an etching area of only 658 μm2.
New approach to automated fingerprint matching

Fingerprint verification is one of the most widespread techniques of personal identification. This paper describes the design of am minutiae-based fingerprint verification system including image preprocessing, feature extraction and fingerprint matching. Image preprocessing comprises the extraction of the region of interest, ridge segmentation, and ridge thinning. The features extracted from a fingerprint include fingerprint minutiae, i.e. ridge endings, and ridge bifurcations, as well as other related characteristics meant to improve the matching performances. The list of attributes of each minutia is extended with a feature vector, that resembles information extracted from the neighborhood region of the minutia. A measure of similarity between two minutiae can be expressed in terms of the distance between their corresponding feature vectors. We investigate two matching techniques based on the new approach of similar minutiae detection. A database containing 168 fingerprint images is used for experiments. The results reveal that the proposed system can achieve a good verification accuracy on this database. In addition, the proposed system meets the time requirements of practical acceptability as long as the average time for a verification is below 1.2 sec on a Sun ULTRA 1 workstation.
THE NUCLEUS OF THE CYGNUS A GALAXY

Newly obtained high resolution optical images of the prototypical luminous radio galaxy Cygnus A (3C 405) indicate an inhomogeneous distribution of obscuring dust and, in combination with previous data, three types of radiation (stellar and blue featureless continuum as well as luminous line emission) in its central regions. The galaxy should not be classified as a colliding pair of galaxies, nor as a dust-lane galaxy. The alleged double nucleus finds its origin in heavy obscuration coupled to excess line emission in the central regions of an otherwise normal giant elliptical galaxy. A strongly reddened nuclear component, coincident with the Cygnus A radio core, is found to emit faint but concentrated narrow line emission. All data appear consistent with identification of Cygnus A as a radio-loud quasar having its radio axis oriented at about 35-degrees from the sky plane. The presumed dust torus obscuring the quasar continuum is inferred to be smaller than 800 parsecs.
Optimum formulation of cathode mix for a multi-response set-up using design optimality criteria

Optimal formulation of cathode mix for zinc-carbon dry cell is a challenging task to the battery manufacturers, the performance of which is characterised by a set of seven performance characteristics (responses). Standard experimental designs like Box-Behnken design, central composite designs are unable to conclude the optimal experimental setting due to the problem of infeasibility or non-orthogonality. This paper makes an attempt to determine the feasible and optimum factor setting of cathode mix formulation while optimising the multiple performance characteristics of zinc-carbon battery. First, a technically feasible and nearly orthogonal design is achieved within the design space using design optimality criteria. Then, five different multi-response optimisation techniques are applied to select the factor setting combination that simultaneously optimises all the responses. All the five methods suggest a particular combination of factors as the optimal formulation of cathode mix.
The Ehrhart polynomial of a lattice polytope

The problem of counting the number of lattice points inside a convex lattice polytope in R' (a polytope whose vertices have integer coordinates) has been studied from a variety of perspectives. Here we use the Poisson summation formula and related techniques in Fourier analysis to obtain a formula for the number of lattice points inside all integral dilates of a lattice polytope. We show that an associated generating function has an explicit representation in terms of sums of cotangents, which are higher-dimensional generalizations of Dedekind sums. Let En denote the n-dimensional integer lattice in R', and let P be an n-dimensional lattice polytope in R', which is a compact simplicial complex of pure dimension n whose vertices lie on the lattice. Consider the function of an integer-valued variable t that describes the number of lattice points that lie inside the dilated polytope tP:
MODELING LONG‐MEMORY PROCESSES FOR OPTIMAL LONG‐RANGE PREDICTION

We look at the implications of modeling observations from a fractionally differenced noise process using an approximating AR (p) model. The approximation is used because of computational difficulties in the estimation of the differencing parameter of the fractional noise model. Because the fractional noise process is long-range dependent, we assess the applicability of the approximating autoregressive (AR) model based on its long-range forecasting accuracy compared with that of the fractional noise model. We derive the asymptotic k-step-ahead prediction error for a fractional noise process modeled as an AR(p) process and compare it with the k-step-ahead prediction error obtained when the model for the observed series is correctly specified as a fractional noise process and the fractional differencing parameter d is either known or estimated. We also assess the validity of the asymptotic results for a finite sample size via simulation. We see that AR models can be useful for long-range forecasting of long-memory data, provided that consideration is given to the forecast horizon when choosing an approximating model.
The asymptotic distribution of the sum of weighted squared residuals in binary choice models

It is claimed by some authors that the distribution of the sum of weighted squared residuals, used as a goodness of fit measure in binary choice models, behaves for large n as a x2n– k–1 distribution. This claim seems to be based on a false analogy with the well–known Pearson x2 statistic for frequency tables with a fixed number of cells and cell sizes tending to infinity. We derive the asymptotic (normal) distribution and show that the approximation by the x2 distribution in general will not be valid. A new x2 test is proposed based on the asymptotic normality of the measure.
Multicomponent Transient Droplet Vaporization with Internal Circulation: Integral Equation Formulation and Approximate Solution

The problem of transient droplet vaporization in a hot convective environment is examined. A model that accounts for liquid-phase internal circulation, transient droplet heating and species diffusion, and axisymmetric gas-phase convection is used. The coupled vaporization problem is formulated as a Volterra-type integral equation with the liquid-phase temperature and species concentration at the droplet surface being unknown functions of time. The integral equation formulation is subsequently transformed into a system of first-order ordinary differential equations, which are solved by the Runge-Kutta scheme. Since only the liquid-phase temperature and species concentration at the droplet surface are needed for determining the vaporization rate and the heat flux, the integral equation formulation has the advantage of eliminating the spatial dependence from the problem, thereby reducing the amount of compulation time.
From dynamic moduli to molecular weight distribution: A study of various polydisperse linear polymers

The linear viscoelastic behavior of various polydisperse linear polymers in the melt is used to predict their average molecular weights and polydispersity index. The method is based on simplified molecular dynamics and has been previously shown to enable a correct description of the dynamic moduli of polypropylenes from the knowledge of their molecular weight distribution (MWD). This so-called forward calculation only requires a few parameters, namely the scaling law for the zero-shear viscosity of narrow fractions η0=f(M), the plateau modulus GN0, and the value of the molecular weight between entanglements Me. The main goal of the present work is to find a solution to the “inverse” problem. To avoid the problem of becoming ill-posed, the shape of the MWD has to be prescribed. Using the assumption of a typical logarithmic bell-shaped Wesslau MWD, the method has been proven to be successful for the recovery of the weight average molecular weight and of the polydispersity index of many linear polymers in a .
Physical-model-based scatter correction in mammography

Scatter might significantly alter the diagnosis in mammography. For example, the sharpness of a mass edge is an important indicator of malignancy. Unfortunately scatter can blur the edges and so make the diagnosis harder. Sharpness enhancement, based on image processing might wrongly sharpen a smooth edge and so alter the diagnosis. We present here a scatter correction method based on the physical equations. The main problem of this approach lies on the non-knowledge of the three-dimensional structure of the object. In order to be able to calculate the map of scattered intensity using the physical laws, we propose an approximation of this structure derived from the primary x-ray flux map representative of its projection. This approximation takes into account the physical parameters relative to x-ray interactions in breast tissues, as well as geometric parameters characterizing the acquisition procedure. This approximation allows us to build an equivalent object for x- ray photons scattering, and the physical laws can be applied to this equivalent object. The validity of this approximation has been evaluated on simulated objects. Finally to remove the scattering flux, we propose an inversion scheme to build the primary flux from the observed flux. The obtained primary flux map is then representative of the projection of the 3D structures of the breast. To validate our scatter correction model, we have developed a direct simulation model taking into account the true 3D model is then compared to the result from the approximated model. The performances of our scatter correction approach will be validated on phantoms representative of the structure and the components of the breast.
Heat flows through plasma sheaths

Plasma heat flow to material surfaces through sheaths is studied, taking several key physics factors into account. Electron emission from the surface, which breaks a thermal insulation of the sheath, is studied in both thermoelectron emission (TEE) and secondary electron emission (SEE), in which a correct expression under space charge limited condition is given for arbitrary sheath voltages. Nonlinear thermal bifurcation induced by electron emission is analyzed in the experiment and the theory. The local heat flow was found to be enhanced by a thermal contraction induced by cross-field potential variation in a plasma. An enhancement of SEE of hydrogen-absorbed graphite, and a suppression of SEE by the gyromotion of emitted electrons in obliquely incident magnetic field are identified. The effects of ion reflection on the surface and ponderomotive force are also discussed in terms of energy transmission factor δ. An anomaly of δ in detached recombining plasmas is discussed.
The energetics of molecular clouds. I - Methods of analysis and application to the S255 molecular cloud

This paper is the first of a series that result from a program to collect complete molecular line, radio continuum, and infrared data on a group of relatively simple, nearby molecular clouds. These data are used to determine the physical properties of the molecular clouds and to analyze the energetic relationship between the gas and the dust in the clouds. The analysis includes estimates of the kinetic temperature, gas density, gas cooling rate, and dust cooling rate. The cooling rates are then compared to relevant heating rates from collapse, and from radiative heating by nearby stars and embedded infrared sources. In this paper, the methods of analysis are described and applied to the molecular cloud associated with S255. The most salient results are the following: (1) The primary energy flow is through the dust, which is cooled by far-infrared radiation. (2) The gas cooling rate is much less than the dust cooling rate. (3) The primary heat sources appear to be nearby stars, but an embedded infrared source is responsible for at least local heating. (4) There is a strong enhancement of molecular density, as well as temperature, centered on the embedded infrared source. (5) A large far-infrared flux (approx.10/supmore » 3/ Jy) is predicted. (6) Suitable far-infrared and submillimeter measurements of this cloud would provide strong tests of molecular cloud models in which the gas is heated by collisions with dust. « less
Space Weather Studies in Australia

Space weather—the space-based phenomena that affect human and technological systems—can damage orbiting satellites and harm humans in space. But on a more regional level, space weather can induce currents on long conductors, such as pipelines and power lines. It can also disrupt radio communications between ground locations and aircraft. Most Northern Hemisphere countries monitor regional effects from adverse space weather in their hemisphere. Their collective research and calculations provide a comprehensive view of the phenomena that affect their region. By contrast, fewer research and monitoring efforts are directed toward understanding regional effects of space weather surrounding the South Pole region, although some programs do exist (e.g., Scientific Committee for Antarctic Research (SCAR) and activities developed during the International Polar Year). Australia has the largest ground-based, space weather network in the Southern Hemisphere, a breadth needed to provide continentwide services over a range of geomagnetic and geographic coordinates and over a highly variable space environment. In part because Australia emerged as a regional leader after World War II, government officials created the Ionospheric Prediction Service (IPS) in 1948, an early space weather– monitoring agency to provide advice on the effective use of the ionosphere to support highfrequency (HF) radio communications. During the 1957–1958 International Geophysical Year (IGY) this role was extended to include shortterm alerts for fadeouts during solar flares and ionospheric and geomagnetic storms. After IGY, a growing number of geophysical customers found the HF communicators’ alerts and storm warnings useful. Like in many countries around the world, the growing customer base, together with the immediacy of the Internet in the early 1990s, led to the development of an increasingly wide range of space weather services. Yet services to mitigate space weather effects are only one side of Australia’s efforts to understand solarterrestrial interactions. Because highly complex processes can lead to effects that the services seek to mitigate, research has a wide role to play in understanding the scope of space weather effects in Australia.
Observations of the eddy fluxes of heat and vapour over the sea

The results are reported of 61 observations of eddy fluxes of heat and vapour at different heights above the sea surface in the trade wind regime off the eastern Australian coast at latitude 16.51°S. The flux gradients were found to be consistent with observed temporal changes in temperature and mixing ratio as the air moved over the sea. The measured fluxes were found to agree with those calculated by bulk aerodynamic methods on the assumption of a 2°C sea-air temperature difference. The evaporation rate deduced from the vapour flux measurements is about 7 mm day −1.
Multifrequency observations of the optically active radio-quiet quasar GQ Comae. II - Ultraviolet, optical, and infrared continuum variability

This paper summarizes the data and preliminary results of a 3 yr long project to monitor the continuum variability of GQ Comae (PG 1202+281) from 0.12 μm to 3.5 μm. Substantial variability in the optical/ultraviolet flux was observed. The variability is examined using a geometrically thin accretion disk model. The model is able to reproduce the variations, but contains problems with physical consistency. A comparison of the optical/ultraviolet data and the infrared data indicates that the flux at 2.2 μm did not respond to the optical-ultraviolet continuum increase until nearly 250 days after the outburst and suggests that the variable flux at this wavelength is due to heated dust
Neutral stellar winds that drive bipolar outflows in low-mass protostars

The Arecibo radio telescope at the 21-cm line of atomic hydrogen has been used to detect a neutral atomic wind in the bipolar flow source HH 7-11. An atomic mass of about 0.015 solar associated with the rapidly flowing gas is deduced. The stellar mass-loss rate is roughly 3 x 10 to the -6th solar mass/yr if the crossing time of the decelerating wind is 5000 yr. The excess emission in the H I line core gives a total duration of the outflow of about 70,000 yr. A detailed analysis of the H I line shape yields a reasonable deceleration rate for the atomic wind if the stellar wind continuously entrains ambient molecular gas as it propagates from the protostar. A stellar wind with the described characteristics and a terminal velocity of 170 km/s would be more than sufficient to drive the known extended CO bipolar outflow in HH 7-11. 58 references.
Femtosecond laser excitation of the semiconductor‐metal phase transition in VO2

We have measured the subpicosecond optical response of a solid‐state, semiconductor‐to‐metal phase transition excited by femtosecond laser pulses. We have determined the dynamic response of the complex refractive index of VO2 thin films by making pump‐probe optical transmission and reflection measurements at 780 nm. The phase transition was found to be largely prompt with the optical properties of the high‐temperature metallic state being attained within 5 ps. The ultrafast change in complex refractive index enables ultrafast optical switching devices in VO2.
Field-based research in fluvial hydraulics: potential, paradigms and challenges

ABSTRACT Field-based research has always been a source of inspiration and a driving force in experimental and theoretical fluvial hydraulics, essentially underpinning all major developments in this area over the past few decades. The recent emergence of advanced measurement capabilities for field applications opens new avenues and opportunities for the refinement of the existing predictive approaches and for addressing forthcoming hydro-environmental problems. This paper considers historic hydraulic field research and outlines recent developments and current trends. Useful definitions are introduced to aid the standardization of various field activities. A method of field experimentation is discussed employing recent examples, and challenging tasks that appeal for application of field methods are highlighted. Innovative techniques are briefly discussed as the preconditions for the development of novel approaches for field research.