Miracle-dz/UniFAR-FTUs huggingface dataset:
Integer Programming Solution of a Classification Problem

A classification problem is presented in which it is desired to assign a new individual or observation with k characteristics to one of two distinct populations based upon historical sets of samples from the two populations. The resulting classification problem is formulated as a mixed-integer programming problem. The solution, which can be obtained through use of a partitioning algorithm based on Benders decomposition, provides a nonparametric classification statistic which minimizes the expected total cost of misclassification. Also, an enumeration algorithm is developed for the special case of k = 2. Monte Carlo studies are reported which compare the results of the enumeration algorithm with Anderson's "normal" procedure for different underlying distributions. The performance of the enumeration algorithm is shown to be significantly better than Anderson's normal procedure for distributions with uncorrelated normal populations with unequal covariance matrices and for uncorrelated skewed populations with equal covariances.
A remote acceptance probe and illumination configuration for spectral assessment of internal attributes of intact fruit

Near infrared spectroscopy can be employed in the non-invasive assessment of intact fruit for eating quality attributes such as soluble solid content (SSC). Rapid sorting is dependent on a suitable non-contact geometry of fruit, light source and detector assembly, optimized for a given fruit commodity. An optical system was designed with reference to distribution of SSC and light penetration into rockmelon fruit. SSC of mesocarp tissue was not significantly different over the greater part of the proximal-distal axis of the fruit, particularly in the vicinity of the fruit equator. There was also no consistent variation in SSC of mesocarp tissue with respect to radial position of sampling. Mesocarp SSC was higher (~3% w/v) closer to the seed cavity. The optical sampling system was therefore designed to assess an equatorial position on the fruit. Light penetrating a rockmelon fruit was empirically assessed to be diffuse at a depth of <15 mm from the fruit surface. Signal decreased in an exponential proportionality with depth into the fruit, but was still detectable at depths in excess of the seed cavity of rockmelons. A partial transmittance optical design was employed, with a collimated light source interrupted by a central light stop, and a detector viewing the shadowed region of the sample. This system did not physically contact the sample. It was compared to a system with a light excluding `contacting' shroud between the detector and the fruit surface. The performance of calibrations generated using the non-contact configuration was not significantly different than for the configuration requiring contact.
Low‐metallicity Star Formation and Pop III‐II Transition

The first stars in the universe were typically very massive, but those near us are not. The metallicity in the star‐forming gas is thought to have played a key role in this transition of characteristic stellar mass scale. By studying the evolution of low‐metallicity star‐forming clouds up to the formation of protostars by way of radiation hydrodynamics with spherical symmetry, we discuss their fragmentation mass scales. The critical metallicity for low‐mass fragmentation is in the range of Zcr = 10−6−10−5Z⊙. Although the exact value is still unknown due to uncertain dust nature in the early universe, the small value of Zcr means that low‐mass star formation begun just after the first episode of metal enrichment. We also evaluate the upper limit on the stellar mass by the stellar feedback. Owing to the higher density in the envelope and thus higher protostellar accretion rate, the upper limit of stellar mass increases toward lower matallicity.
On a Simple Numerical Method for Computing Stieltjes Integrals in Reliability Theory

A simple method of calculating Stieltjes integrals is proposed. The method is essentially the two-point (trapezoidal) rule from numerical analysis. Two theorems yielding error bounds are given. When error requirements are modest (two or three significant decimal places) the method is fast and inexpensive. Examples are given solving the Renewal equation from reliability theory. A program for an HP-41C hand calculator is given, which solves the renewal equation.
A Gravito-electrostatic Sheath Model for Surface Origin of Subsonic Solar Wind Plasma

Parker's model prediction of an unbounded solution for the supersonic solar wind plasma (SWP) requires a subsonic origin at the solar surface. The transition to supersonic SWP flow is well understood by analogy with the de Laval nozzle. The basic physics, however, of the self-consistent solar surface emission of subsonic SWP is still not very clear. We propose a theoretical model based on a gravito-electrostatic plasma sheath (GES) to investigate the surface emission mechanism of the quasi-neutral SWP. The basic equations for the interior steady state description are solved numerically as an initial-value problem under spherical geometry. A bounded solution for the solar self-gravity distribution is found to exist, meaning that a global quasi-hydrostatic equilibrium is formed at some distance from the heliocentric origin. This defines the solar surface boundary in our model, which lies at radius ξ ~ 3.5 (in units of the Jeans length). A minimum speed of ~3.0 cm s-1, corresponding to Mach number ~10-7, is obtained at this location. Consequently, a subsonic origin of the solar interior plasma flowing radially outward becomes a physical reality. Our model requires a mean electron temperature Te ~ 107 K (=1 keV) for the numerical results to match the standard solar values. The boundary is found to be negatively biased, with a normalized value of the electrostatic potential θs ~ -1 (=1 kV). It is conjectured that our model provides an interesting new physical basis for understanding the collective dynamical coupling processes of solar interior and exterior (heliosphere) regions through local, as well as global, modes of GES-induced collective waves, instabilities, and oscillations.
Multi-Pulse Evolution and Space-Time Chaos in Dissipative Systems

We study semilinear parabolic systems on the full space Rn that admit a family of exponentially decaying pulse-like steady states obtained via translations. The multi-pulse solutions under consideration look like the sum of infinitely many such pulses which are well separated. We prove a global center-manifold reduction theorem for the temporal evolution of such multi-pulse solutions and show that the dynamics of these solutions can be described by an infinite system of ODEs for the positions of the pulses. As an application of the developed theory, we verify the existence of SinaiBunimovich space-time chaos in 1D space-time periodically forced Swift-Hohenberg equation.
Measuring the Effectiveness of a Mathematics Support Service: An Email Survey.

Over the last decade the ‘mathematics problem’ (students lacking basic mathematical skills on entry into higher education), and proposed solutions of this problem have been widely debated. One method to help combat this issue has been the introduction of mathematics support centres across higher education institutions. This article describes the results of an e-mail survey distributed to 40 universities to gain information regarding their mathematics support provision, with particular focus on how universities measure the effectiveness of the support available. With ever increasing pressure for impact to be validated, this article will give a contemporary standing of the current mechanisms adopted by mathematics support centres (nationally and internationally) used to determine effectiveness.
On boundary correspondences under quasiconformal harmonic mappings between smooth Jordan domains

A quantitative version of an inequality obtained in [ 8 , Theorem 2.1] is given. More precisely, for normalized K quasiconformal (q.c.) harmonic mappings of the unit disk onto a Jordan domain Ω ∈ C1, μ (0 < μ ≤ 1), we give an explicit Lipschitz constant depending on the structure of Ω and on K. In addition, we give a characterization of q.c. harmonic mappings of the unit disk onto an arbitrary Jordan domain with C2, α boundary in terms of the boundary function using the Hilbert transform. Moreover, a sharp explicit quasiconformal constant is given in terms of the boundary function.
Major Changes to the LHCb Grid Computing Model in Year 2 of LHC Data

The increase of luminosity of the LHC in 2011 also introduced an increase of computing requirements for data processing. This paper describes the data processing operations during 2011 prompt reconstruction as well as the end of year re-processing of the full data sample. It further gives an outlook to next evolutionary steps in the LHCb computing model for 2012 data processing and beyond.
High power and high brightness from an optically pumped InAs/InGaSb type-II midinfrared laser with low confinement

We report on optically pumped semiconductor lasers emitting near 3.8 μm that exhibit high power and low output divergence. The lasers incorporate multiple InAs/InGaSb/InAs type-II wells imbedded in an InGaAsSb waveguide that is designed to absorb the pump emission. When operated at 85 K, 0.25 mm×2.5 mm broad area devices produce >5 W of peak power under long pulse conditions. Moreover, these extremely bright devices exhibit a fast axis divergence of only ∼15° full width at half maximum (FWHM), coupled with a slow axis divergence of ∼6° FWHM. The first is due to the reduced optical confinement in the transverse direction, while the latter is attributed to the suppression of filament formation, which is another beneficial consequence of the low optical confinement.
Optically controlled slow and fast light in optical fibers using stimulated Brillouin scattering

We demonstrate a method to achieve an extremely wide and flexible external control of the group velocity of signals as they propagate along an optical fiber. This control is achieved by means of the gain and loss mechanisms of stimulated Brillouin scattering in the fiber itself. Our experiments show that group velocities below 71 000 kms on one hand, well exceeding the speed of light in vacuum on the other hand and even negative group velocities can readily be obtained with a simple benchtop experimental setup. We believe that the fact that slow and fast light can be achieved in a standard single-mode fiber, in normal environmental conditions and using off-the-shelf instrumentation, is very promising for a future use in real applications. © 2005 American Institute of Physics.
Erosion Model for the Sungrazing Comets Observed with the Solar and Heliospheric Observatory

The objectives of this study are to model and interpret quantitatively the brightness variations of 27 Solar and Heliospheric Observatory (SOHO) sungrazers. The light curves, published by Uzzo et al. and by Biesecker et al., are shown to provide information on a proposed erosion process, which consists of continuous, progressive bulk fragmentation and sublimation of these minicomets on their approach to the Sun. The erosion rate and the time of peak signal are determined primarily by an effective latent energy of erosion (analogous to a sublimation heat), which is found to have a bimodal distribution with sharp peaks near 34,000-35,000 and 40,000-41,000 cal mol-1 for the main components of the 27 objects. Their derived initial diameters are between 17 and 200 m. With the given range of erosion energies, a sungrazer that is to survive its return to the Sun needs to be more than 1-1.4 km in diameter, depending on its perihelion distance. The shape of the light curves at heliocentric distances smaller than 7 R☉ is interpreted to indicate the existence of fairly sizable, but unresolved, close companions, which appear to have split off from their parent bodies shortly before, if not during, observation. All subfragments that survived longer than the main components had erosion energies significantly higher than the average, between 45,000 and nearly 90,000 cal mol-1. There is also evidence for subfragments with erosion energies lower than 34,000 cal mol-1. Because the erosion process is believed to be dominated by continual fragmentation, the existence of such subfragments should not be surprising. The brightness of the SOHO sungrazers at peak signal is mass diagnostic, and their cumulative distribution varies inversely as the initial mass to a power of 0.56-0.68. Thus, much of the total mass is still locked in the most massive fragments, and the Kreutz system is apparently in an early phase of its evolution.
The Carina dwarf spheroidal galaxy: how dark is it?

Precise radial velocities obtained with a photon-counting echelle spectrograph for a sample of 17 red giants in the Carina dwarf spheroidal galaxy are presented. The calculation of the systemic velocity and central velocity dispersion of Carina is described, the existing data constraining the structural parameters of Carina are reviewed, and an estimate of the central surface brightness of the galaxy is derived. These data are used to estimate the central mass density of Carina, as well as central and global mass-to-light ratios. It is concluded that the inferred mass densities and mass-density limits for all acceptable models imply the presence of a significant DM component in Carina. DM properties of all well-studied dSph systems are summarized and compared.
The aor method for preconditioned linear systems

In this paper we analyse the behaviour of the rate of convergence of the Accelerated Overrelaxation (AOR) method when the linear system Ax = b is preconditioned by performing certain elementary row operations on A or by a single Gauss-Jordan elimination. Under some assumptions we prove that the AOR method applied to the preconditioned systems gives improvements in the rate of convergence.
Fast dynamo action in the ponomarenko dynamo

Abstract An analysis of small-scale magnetic fields shows that the Ponomarenko dynamo is a fast dynamo; the maximum growth rate remains of order unity in the limit of large magnetic Reynolds number. Magnetic fields are regenerated by a “stretch-diffuse” mechanism. General smooth axisymmetric velocity fields are also analysed; these give slow dynamo action by the same mechanism.
Continuing changes in the peculiar nebulous object PV Cephei

Changes in the nebular structure, optical spectrum and stellar brightness of the faint star PV Cephei and the nebulosity associated with it are discussed. Iris photometry of the starlike object at the tip of the fan-shaped nebula reveals irregular variability of approximately 4 magnitudes in the red. Stellar spectra in the region 4300-6750 A taken from December 1976 to April 1980 are similar to the richest emission line spectra of T Tauri stars, while nebular spectra indicate a lack of spherical symmetry. Observations obtained in the infrared reveal a source offset by a few arcsec from the apex of the fan, which is identified with the illuminating star. Radial velocities of CO emission indicate that PV Cep is at the same distance as NGC 7023, and independent estimates lead to an estimated value of 500 pc. Such a distance corresponds to a bolometric luminosity approximately 100 times that of the sun. It is suggested that PV Cep is a T Tauri star that has recently broken through its circumstellar cocoon at a time when highly erratic variability and a strong stellar wind characterize the star.
Shimuravarietäten und Gerben.

Das Problem der Fortsetzbarkeit der Hasse-Weil-Zeta-Funktionen und allgemeiner der motivischen L-Funktionen ist nach wie vor ein zentrales Problem der Zahlentheorie. Es wird oft in zwei Probleme aufgeteilt, die getrennt zu lösen sind. Es ist erstens zu zeigen, daß jede motivische L-Funktion gleich einer automorphen L-Funktion ist, und zweitens, daß jede automorpheL-Funktion fortsetzbar ist. Beide Probleme sind in herzlich wenigen Fällen gelöst und dann nur dank der Bemühungen vieler Mathematiker über lange Zeit.
The Impact of Satellite-derived Winds on Numerical Hurricane Track Forecasting

Abstract While qualitative information from meteorological satellites has long been recognized as critical for monitoring tropical cyclone activity, quantitative data are required to improve the objective analysis and numerical weather prediction of these events. In this paper, results are presented that show that the inclusion of high-density, multispectral, satellite-derived information into the analysis of tropical cyclone environmental wind fields can effectively reduce the error of objective track forecasts. Two independent analysis and barotropic track-forecast systems are utilized in order to examine the consistency of the results. Both systems yield a 10%–23% reduction in middle- to long-range track-forecast errors with the inclusion of the satellite wind observations.
Wave propagation through a random array of pinned dislocations: Velocity change and attenuation in a generalized Granato and Lücke theory

A quantitative theory of the elastic wave damping and velocity change due to interaction with dislocations is presented. It provides a firm theoretical basis and a generalization of the Granato and Luecke model [J. Appl. Phys. 27, 583 (1956)]. This is done considering the interaction of transverse (T) and longitudinal (L) elastic waves with an ensemble of dislocation segments randomly placed and randomly oriented in an elastic solid. In order to characterize the coherent wave propagation using multiple scattering theory, a perturbation approach is used, which is based on a wave equation that takes into account the dislocation motion when forced by an external stress. In our calculations, the effective velocities of the coherent waves appear at first order in perturbation theory while the attenuations have a part at first order due to the internal viscosity and a part at second order due to the energy that is taken away from the incident direction. This leads to a frequency dependence law for longitudinal and transverse attenuations that is a combination of quadratic and quartic terms instead of the usual quadratic term alone. Comparison with resonant ultrasound spectroscopy (RUS) and electromagnetic acoustic resonance (EMAR) experiments is proposed. The present theory explainsmore » the difference experimentally observed between longitudinal and transverse attenuations [Ledbetter, J. Mater. Res. 10, 1352 (1995)]. « less
Monitoring the integrity of massive aluminum structures using PZT transducers and the technique of impedance

Safety, performance, economy and durability are essential items to qualify materials for the manufacturing of structures used in different areas. Generally, the materials used for this purpose are formed by composites and sometimes they can present failure during the manufacturing process. Such failures can also occur during use due to fatigue and wear, causing damage often difficult to be visually detected. In these cases, the use of non destructive testing (NDT) has proven to be a good choice for assessing the materials quality. The objective of this work was the electromechanical impedance evaluation of massive aluminum structures using ultrasonic transducers to detect discontinuities in the material. The tests have been done using an impedance analyzer (Agilent 4294A), an ultrasound transducer (1.6 MHz of central frequency), two types of PZT ceramics (0.267 mm and 1 mm thickness) and four aluminum samples (250 x 50 x 50 mm) with the transducer placed at three different regions. One sample was kept intact (reference) and the others were drilled in three positions with different sizes of holes (5 mm. 8 mm and 11 mm). The electromechanical impedance was recorded for each sample. The root mean square deviation index (RMSD) between the impedance magnitude of the reference and damaged samples was calculated and it was observed an increase in the RMSD due to the increase of the diameter of the holes (failures) in the samples completely drilled. The results show that the proposed methodology is suitable for monitoring the integrity of aluminum samples. The technique may be evaluated in characterizing other materials to be used in the construction of prostheses and orthoses.
Cellular Phones Helping to Get a Clearer Picture of Kinematics.

The main purpose of this paper is to add to the list of examples of how cell phones may be used as teaching tools in the classroom.1 One very interesting example of this comes from the study of projectile motion, the classical “cannon ball” problem. This problem is central to the study of kinematics, the very first topic a student meets in physics. Our approach exploits the fact that these days almost all students carry cellular phones and the vast majority of the phones have built-in cameras.
Surface effects on phase transitions in ferroelectrics and dipolar magnets

A phenomenological theory is developed to describe the change of the local spontaneous polarization in the vicinity of a free surface of a ferroelectric thin film which is kept between metallic electrodes. It is shown that depolarizing field effects reduce the deviation of this local polarization from its bulk value, as compared to surface effects on phase transitions in other systems. In particular, the critical exponents describing the behavior of the local polarization in the vicinity of the Curie temperature ${T}_{C}$ are the same as the bulk exponents and only critical amplitudes are changed. This behavior contrasts to phase transitions in other systems (antiferroelectrics, ferro- and antiferromagnets, ordering alloys etc.) where different exponents are predicted. In order to improve upon this Landau-type theory by taking into account the effects of statistical fluctuations near ${T}_{C}$, recent results of renormalization-group theory are used to estimate logarithmic correction factors which should modify the critical behavior of the local polarization. Finally the experimental implications of our results are briefly discussed, and also a discussion of surface effects on the phase transition of dipolar magnets is given.
Introduction to the Theory of Grammar

In the last 30 years, linguists have built a considerable and highly sophisticated body of work on generative grammar. Today the field is more active than ever before. "Introduction to the Theory of Grammar" makes available to teachers and students of syntax a comprehensive critical review of the main results of present day grammatical theory and shows how they were achieved. It presents the central questions, shows how and why they were asked, what the answers were, and how these have led to new questions.Part I discusses the way in which the overly rich, descriptive rule systems of the fifties and sixties have gradually been replaced by simpler, more constrained rule systems. Much of the work originally done by stipulations in the rules themselves has been taken over by general, universal principles which govern the form and functioning of these rules and the properties of their inputs and outputs. The establishment of such a theory of principles is the main topic of Part II.Part III addresses the problem of how semantics fits into grammar and elaborates a conception of how the syntactic properties of logical representations can be integrated into the overall theory of grammar. The rules and principles of grammar developed in these parts account for grammatical phenomena in an essentially modular way, and this system of modules, which constitutes the study of grammar today, is established in Part IV.An Epilogue describes such current developments as generalized binding, phrase structure, small clauses, tree geometry and NP-structure.Henk van Riemsdijk is full professor in the Department of Language and Literature, Tilburg University, Holland. Edwin Williams is professor of linguistics, University of Massachusetts, Amherst. "Introduction to the Theory of Grammar" is twelfth in the series Current Studies in Linguistics.