Miracle-dz/UniFAR-FTUs huggingface dataset:
Minimal excessive measures and functions

Let H be a class of measures or functions. An element h of H is minimal if the relation h = h, + h2, hI, h2 E H implies that hI, h2 are proportional to h. We give a limit procedure for computing minimal excessive measures for an arbitrary Markov semigroup T7 in a standard Borel space E. Analogous results for excessive functions are obtained assuming that an excessive measure y on E exists such that T,J = 0 if f = 0 y-a.e. In the Appendix, we prove that each excessive element can be decomposed into minimal elements and that such a decomposition is unique.
Thermal structure of neutron stars with very low accretion rates

Steady state models of neutron stars accreting matter with the heavy-element content 0.000002≤Z≤0.02 at the rate 10 −16 ≤M≤10 −11 M . yr −1 are presented. The models have steady state envelopes, with stationary hydrogen and helium-burning shell sources. The capture of electrons on protons is taken into account; this process is important in models with the lowest heavy-element content. Two types of neutron star models are calculated: ordinary and with pion-condensed cores
Probabilistic generation of finite classical groups in odd characteristic by involutions

Abstract An involution in a finite n-dimensional classical group G over a field of odd order q is called (α, β)-balanced if the dimension of its fixed point subspace is between αn and βn. Balanced involutions play an important role in recent constructive recognition algorithms for finite classical groups in odd characteristic. For a given sequence of conjugacy classes of balanced involutions in G, a c-tuple (g 1, . . . , gc ) is a class-random sequence from 𝒳 if, for each i = 1, . , c, gi is a uniformly distributed random element of , and the gi are mutually independent. We show that there is a number c = c(α, β) such that for large enough n, for a given such sequence 𝒳 of length c, a class-random sequence from 𝒳 generates a subgroup containing the generalized Fitting subgroup of G with probability at least 1 – q –n .
Direct analytic model of the L-curve for Tikhonov regularization parameter selection

We present an approximation to a direct, non-parametrized analytic expression for the L-curve used in the regularization of ill-conditioned linear systems which is constructed starting from the exact solution for the case of a linear operator with just one singular value. For the general case, this expression suggests one choice of Tikhonov regularization parameter per singular value at which to compute the curvature of the log–log L-curve plot. It suffices to test a small number of candidate values in the vicinity of the mean square residual of the unregularized solution. Monte Carlo simulations show that choosing the maximum curvature generated from within this set of candidate values selects an optimum value of the regularization parameter which yields a solution whose norm typically lies within a fraction 0.125/κL of the exact L-curve value, where κL is the maximum log–log curvature at the L-curve corner. For large scale ill-posed problems, a new regularization parameter selection method based on the construction of an L-curve from a single sequence of conjugate gradient iterates is presented. It includes a new stopping rule for terminating the iterative solution of large scale least squares problems. Numerical experiments show that the accuracy of the regularized solution obtained with the value of the regularization parameter at the corner of this curve is close to that of the exact L-curve solution.
An New Fuzzy Support Vector Machine for Binary Classification

In this paper, we proposed a new fuzzy support vector machine(called L2–FSVM here), which error part of object is L2–norm.Meanwhile we introduce a new method of generating fuzzy memberships so as to reduce to effects of outliers. The experimental results demonstrate that the L2-FSVM method provides improved ability to reduce to effects of outliers in comparison with traditional SVMs and FSVMs, and claim that L2–FSVM is the best way to solve the binary classiﬁcation in the three methods stated above.
Spatial filtering using pinholes at COAST

Visibility measurements obtained with optical astronomical interferometers are corrupted by random wavefront distortions of atmospheric origin. In this paper we discus how spatial filtering using pinholes can lead to increased measured visibility, improved signal-to-noise ratio and reduced dependence on seeing fluctuations. The potential for calibrating visibility measurements without resorting to a separate calibrator target is also discussed. Results of preliminary pinhole experiments carried out with the Cambridge Optical Aperture Synthesis Telescope are presented.
Surface electromagnetic wave excitation on one-dimensional photonic band-gap arrays

Experiments are described on the prism-coupled excitation of surface electromagnetic waves in one-dimensional photonic band-gap arrays. The low loss of photonic band-gap materials leads to narrow angular reflectivity resonances and high surface fields. These attributes, coupled with the ability to engineer the optical properties of photonic band-gap arrays, suggest these materials as powerful replacements for metal films in many applications that make use of surface-plasmon resonance.
Enhanced effect of electron-hole plasma emission in Dy, Li codoped ZnO nanostructures

Pink branched Dy3+ and Li+ codoped ZnO nanowires were synthesized by simply annealing the polymeric precursor. For the undoped sample, electrons at the bottom of the conductor band return to the ground state via a process of free exciton and defect intermediate level, and subsequently emit 3.2 and 2.4 eV photons. Furthermore, their intensities both increase while their positions are almost invariant with increasing excitation intensity. For the doped nanostructure, compositional inhomogeneity results in localization of nonequilibrium carriers and enhances the photoluminescence performance. The near-band edge emission shows higher emission efficiency and is dominated by the transition of free electrons to free holes. Moreover, it also exhibits a power-dependent redshift and a broader and more asymmetric line shape on its lower-energy side with increasing excitation intensity. For the green emission in codoping ZnO nanostructures, the formation of deeper traps from the complexes of defects and impurities re.
p‐n photoelectrolysis cells

The efficiency of photoelectrolysis with solar radiation can be greatly enhanced by using simultaneously illuminated n‐ and p‐type electrodes. An energy level scheme for heterotype and homotype p‐n photoelectrolysis cells is presented which explains the enhanced efficiency. Data are presented for the homotype n‐GaP/p‐GaP and the heterotype n‐TiO2/p‐GaP systems which support the energy model. H2 and O2 are produced in the n‐TiO2/p‐GaP cell without the need of an external anodic bias.
LASER-DRIVEN POPULATION TRANSFER IN FOUR-LEVEL ATOMS : CONSEQUENCES OF NON-ABELIAN GEOMETRICAL ADIABATIC PHASE FACTORS

We analyze the influence of three pulsed laser fields interacting with a four-state atomic system for which there occur two degenerate population-trapping dressed states. We present a simple expression for the geometrical phase acquired by such an atom during a stimulated Raman adiabatic passage (STIRAP) process using a delay between Stokes and pump pulses, during which the two Rabi frequencies adiabatically traverse a closed path in the parameter space. We describe techniques that can produce (geometrical) state-vector phases that are independent of the longitudial velocity with which atoms move across a laser beam, and that are insensitive to radiative decay from the intermediate excited state. The geometrical phase can be changed by changing the relative delay of the pulses. The geometrical phase can be measured by observing the population in atomic states. We show that when the pump and Stokes pulses are properly timed, high population transfer from the initial state to the target state is achieved. In the adiabatic limit the robustness of the population transfer is equivalent to that of STIRAP.
The convex hull of sub-permutation matrices

1. Introduction. A combinatorial theorem [1; 3] usually referred to as "the marriage problem" or "the problem of distinct representa-tives" has the following matrix formulation; the convex hull of the set of all n by n permutation matrices is the set of all n by n doubly stochastic matrices. In this note the above theorem is generalized. The following notation and definitions will be used. A will represent an n by n matrix with non-negative real entries aij; S will repre
LARGE AND MODERATE DEVIATIONS PRINCIPLES FOR KERNEL ESTIMATION OF A MULTIVARIATE DENSITY AND ITS PARTIAL DERIVATIVES

This paper studies the large deviations behaviour of the kernel estimator of a probability density f, by considering the case when the kernel takes negative values. It establishes large and moderate deviations principles for the kernel estimators of the partial derivatives of f. The estimators of the derivatives exhibit a quadratic behaviour for both the large and the moderate deviations scales, whereas for the density estimator there is a classical gap between the large deviations and the moderate deviations asymptotics.
On the theory of superconductivity: the one-dimensional case

The one-dimensional case of free electrons interacting with lattice displacements is solved by a self-consistent method. It is found that for a certain range of the interaction parametera single sinusoidal lattice displacement is strongly excited in the lowest level of the system. Its wave-length is such as to create an energy gap in the single-electron energy spectrum with all states below it filled, and all above it empty. This periodic lattice displacement plays the role of an ‘inner field’ and leads to periodic fluctuation in the electronic density in such a way that the two stabilize each other. In an infinite medium described by a periodic boundary condition they are not fixed absolutely in space, but only relative to each other. Excitation of electrons across the gap leads to a decrease in both the electronic density fluctuations and the width of the gap. The whole system, electrons plus lattice displacements, can move through the lattice without being disturbed provided the velocity v is sufficiently small. The inertia of this system is equal to that of all electrons augmented by a term due to the lattice displacements. Elastic scattering of individual electrons which normally leads to the residual resistance is impossible if v is sufficiently small. The linear specific heat of normal electrons is eliminated and replaced by an exponential term.
A non-smooth control law and time-optimality notions for the acrobot

We propose a discontinuous control law to pump energy into the acrobot system to place the system at a certain energy level. Filippov calculus is used to establish convergence of the system trajectory to the desired energy set. The bang–bang nature of the control law prompts us to investigate whether the energy is pumped in minimum time. We then present necessary conditions for time optimality.
Vertical extensions of galactic spiral arms

The vertical structure of the large scale galactic shock along spiral arms is studied, in order to understand the extended features or the ''wings'' of spiral arms observed by Kepner and recently checked by Soukup. Numerical calculations of two-dimensional gas flow were performed for two models of the gas. Our results show that the shock front, standing perfectly perpendicular to the galactic plane, extends impressively above the scale height of the interstellar gas. In the extreme case of isothermal gas, the shock solution exists at any distance from the plane. In a realistic model in which the kinetic temperature of the gas is stratified, increasing with height, the shock can extend up to 700 pc. For both models, although the velocity component perpendicular to the galactic plane is small, the solutions corresponding to layered one-dimensional flow contain no shocks at such heights. In order to study the geometry of the shock front and the flow pattern near it, a simplified model is adopted, in which the Coriolis force is neglected. However, our estimates show that including it will enhance the shock strength. The compression at the shock front makes the gas observable at high latitudes.
The physics of magnetic separation

Abstract Current activity in the field of magnetic separation is reviewed in fundamental terms. The diverse subject matter is ordered into four main groupings whose characteristics are described in terms of numerous devices, both of present-day and historical significance. Existing as well as potential areas of scientific and commercial operation are discussed. The basic principles of recent major developments in high intensity magnetic Separation are closely examined.
The Linear Bias in the Zeldovich Approximation and a Relation between the Number Density and the Linear Bias of Dark Halos

The linear bias of the dark halos from a model under the Zeldovich approximation is derived and compared with the fitting formula of simulation results. While qualitatively similar to the Press-Schechter formula, this model gives a better description for the linear bias around the turnaround point. This advantage, however, may be compromised by the large uncertainty of the actual behavior of the linear bias near the turnaround point. For a broad class of structure formation models in the cold dark matter framework, a general relation exists between the number density and the linear bias of dark halos. This relation can be readily tested by numerical simulations. Thus, instead of laboriously checking these models one by one, numerical simulation studies can falsify a whole category of models. The general validity of this relation is important in identifying key physical processes responsible for the large-scale structure formation in the universe.
Measurement of the angular position of a human extremity based on a multifunctional approach

A novel method for measuring the three-dimensional joint angles of a human extremity simultaneously is presented based on a multifunctional sensing approach. The method proposes a simple and single configuration with minimum sensing elements, which is able to convert obliquity, bending direction and torsion angle to the linear movements of three wires by imitating the status of the skin on the joint using a flexible tube. A prototype is built with three inductances as its outputs, whose results examine the feasibility of the proposed method and give satisfactory accuracy. A simple algorithm to reconstruct three angular parameters is able to provide real-time analysis. The system is multifunctional, easily mountable, low cost and can be used for long-term monitoring of human extremities such as the arm, knee and shoulder.
Robust stabilization of linear time-invariant systems

The problem of robustly stabilizing families of linear time-variant plants consisting of a nominal plant and its frequency domain neighborhood is discussed. Necessary and sufficient conditions are obtained for robust stabilizability of such families of plants. The set of robustly stabilizing controllers is parameterized and the largest achievable stability margin is characterized for a linear time-invariant plant. >
JPEG2000 compressed domain image retrieval using context labels of significance coding and wavelet autocorrelogram

JPEG has been a widely recognized image compression standard for many years. Nevertheless, it faces its own limitations as compressed image quality degrades significantly at lower bit rates. This limitation has been addressed in JPEG2000 which also has a tendency to replace JPEG, especially in the storage and retrieval applications. To efficiently and practically index and retrieve compressed-domain images from a database, several image features could be extracted directly in compressed domain without having to fully decompress the JPEG2000 images. JPEG2000 utilizes wavelet transform. Wavelet transforms is one of widely-used to analyze and describe texture patterns of image. Another advantage of wavelet transform is that one can analyze textures with multiresolution and can classify directional texture pattern information into each directional subband. Where as, HL subband implies horizontal frequency information, LH subband implies vertical frequency information and HH subband implies diagonal frequency. Nevertheless, many wavelet-based image retrieval approaches are not good tool to use directional subband information, obtained by wavelet transforms, for efficient directional texture pattern classification of retrieved images. This paper proposes a novel image retrieval technique in JPEG2000 compressed domain using image significant map to compute an image context in order to construct image index. Experimental results indicate that the proposed method can effectively differentiate and categorize images with different texture directional information. In addition, an integration of the proposed features with wavelet autocorrelogram also showed improvement in retrieval performance using ANMRR (Average Normalized Modified Retrieval Rank) compared to other known methods.
Composition cascade control for chemical reactors

Eventhough the composition control of chemical reactors is an old, widely studied, and still relevant problem in chemical process control, it still presents some aspects that remain unexplored or unresolved. For instance, a unifying approach is needed to systematize the existing ad hoc controller constructions, to rigorously explain their remarkable robustness property, and to explore the possibility of improving their construction and functioning. In this paper, some aspects of these control problems are addressed by resorting to recently developed approaches in constructive non‐linear control, yielding a systematic controller construction coupled to a simple tuning scheme that can be executed with standard tuning rules, a closed‐loop stability criterion, and an explanation of the closed‐loop dynamics behaviour. Specifically, a linear cascade (master/slave) control configuration is proposed, which leads to global internal stability of the controlled system with asymptotic regulation of the output‐stream composition about a given desired setpoint. A simulation example is used to illustrate the results. Copyright © 2002 John Wiley & Sons, Ltd.
Detailed Measurements of Spike Formation in an Axial Compressor

This paper presents new experimental measurements of spike-type stall inception. The measurements were carried out in the single stage Deverson compressor at the Whittle Laboratory. The primary objective was to characterize the flow field in the tip clearance gap during stall inception using sufficient instrumentation to give high spatial and temporal resolution. Measurements were recorded using arrays of unsteady pressure transducers over the rotor tips and hot-wires in the tip gap. Pre-stall ensemble averaged velocity and pressure maps were obtained as well as pressure contours of the stall event. In order to study the transient inception process in greater detail, vector maps were built up from hundreds of stalling events using a triggering system based on the stalling event itself. The results show an embryonic disturbance starting within the blade passage and leading to the formation of a clear spike. The origins of the spike and its relation to the tip leakage vortex are discussed. It has also been shown that before stall the flow in the blade passage which is most likely to stall is generally more unsteady, from revolution to revolution, than the other passages in the annulus. Copyright © 2012 by ASME.
Sensor fault reconstruction and sensor compensation for a class of nonlinear state-space systems via a descriptor system approach

A descriptor system approach is introduced to investigate sensor fault reconstruction and sensor compensation for a class of nonlinear state-space systems with Lipschitz constraints. Letting the sensor fault term be an auxiliary state vector, an augmented descriptor system is constructed. Using the linear matrix inequality technique, a state-space nonlinear estimator is designed for the augmented descriptor plant. Accurate asymptotic estimates of the original system state vector and the sensor fault term are thus obtained readily. By subtracting the estimated sensor fault term from the measurement output, sensor compensation is performed, allowing the existing controller for the original plant (without sensor faults) to continue to function normally even when a sensor fault occurs. Robust sensor fault reconstruction and sensor compensation are also discussed in detail for systems with simultaneous sensor faults, input disturbances and output noises. Finally, numerical examples and simulations are given to illustrate the design procedures and demonstrate the efficiency of the approaches. The sensor fault considered may be in any form, and may even be unbounded. As a result, the present work possesses a wide scope of applicability.
A Detailed Microphysical Model Within a Two-Dimensional Dynamic Framework: Model Description and Preliminary Results

Abstract A two-dimensional anelastic cloud model which incorporates detailed treatments of the water and ice phase is presented. The liquid phase processes considered include condensation, quasi-stochastic coalescence, fallout and breakup, while the ice phase processes include diffusional and accretional growth of ice particles. Results of two cloud simulations are presented. The first case assumes an atmosphere with maritime cloud condensation nuclei (CCN) activation characteristics and considers the warm rain processes only. It was found that with the appearance of precipitation, the model-predicted supersaturations within updraft regions often reach values larger than 5% with respect to water. The second case assumes an atmosphere with continental CCN characteristics and includes the ice phase processes leading to the formation of graupel. The results of the second case illustrate the importance of cloud vertical motions in transporting ice particles from preferential nucleation regions in the upper po.
Spatial Distribution of Radon and Thoron Concentrations Indoors and their Concentrations in Different Rooms of Buildings

The concentrations of radon and thoron were measured in a few old and new types of buildings that had four or six different rooms for a period of 1 year from December 2002 to November 2003 using solid state nuclear track detectors (SSNTDs). The dosimeters containing the detector (LR-115 Type II Film) used in each rooms were fixed 2m above the floor. After an exposure time of 90 days films were etched to reveal tracks. From the track density determined using a spark counter the concentrations of radon and thoron were evaluated. Higher radon and thoron concentrations were observed in older buildings rather than new types and a lecturer hall. This is because types of flooring and ventilation conditions are different for different buildings. Seasonal variation and spatial distribution of these gases from the floor surface and walls were studied and analysed.
Decoding of cyclic codes over the ring F 2 + uF 2 + u 2 F 2

Udaya and Bonnecaze (IEEE Trans Inf Theory 45:2148–2157, 1999) presented a decoding algorithm for cyclic codes of odd length over the ring F 2 + uF 2 . In this study, a simpler approach for decoding cyclic codes with odd length over this ring is proposed. The structure of cyclic codes of odd length over the ring R = F 2 + uF 2 + u 2 F 2 , where u 3 = 0 , is given. A Gray map which is both an isometry and a weight-preserving map from R n to F 24 n is deﬁned and with the use of proposed Gray map, a BCH-like bound for the Lee distance of codes over R is given. Finally, a decoding algorithm is suggested for cyclic codes over R .