Miracle-dz/UniFAR-FTUs huggingface dataset:
The Use of Real-World Computer Models for Computer-Aided Design of Tracking Control Schemes for Induction Motors

The design of tracking controllers for induction motors is usually developed by neglecting the presence of power-supply devices, such as inverters, and measurement apparatuses, e.g., encoders. However, these components represent unmodeled dynamics that are present during the real operating conditions of the induction motor. Since the development of a numerical simulation study represents a low-cost, safe, and fast test to validate the design of tracking control schemes, the need arises to build a computer model of the overall system (i.e., motor, power supply, measurement devices, and tracking controller) as realistic as possible. In this context, the paper describes a computer model for simulation of an induction motor under a tracking control scheme including many real-world effects; namely, encoder's quantization, current sensors' noise, stator current dynamics, presence of a current-controlled voltage-source inverter within a stator current regulator loop, flux observer dynamics, saturation of the control signal, and discrete-time implementation of the control algorithm. The developed computer model is finally used in a case study and the simulation results obtained for an induction motor driving a single-link robotic arm under an H8 tracking control scheme are reported.
Quantum effects in the renormalization group approach to phase transitions

The renormalization group approach to critical phenomena is developed for quantum mechanical problems with non-commuting operators. Applying the theory to the spin 1/2 Ising model with a transverse field Gamma it is found that the critical exponents are those of the Ising model with Gamma =0 if the transition occurs at T>0. However, for transitions at T=0 the critical behaviour of the d-dimensional transverse system corresponds to that of the (d+1)-dimensional Ising model with Gamma =0, in agreement with series expansion predictions. At T=0 the dynamic, as well as static, critical behaviour is given by mean field theory for d>3.
On 3-crossed modules of algebras

In this paper we define 3-crossed modules for commutative (Lie) algebras and investigate the relation between this construction and the simplicial algebras. Also we define the projective 3-crossed resolution for investigate a higher dimensional homological information and show the existence of this resolution for an arbitrary k-algebra.
Moderating effects of subgroups in linear models

SUMMARY Possibilities for moderating effects of a subgrouping variable on strength or direction of an association have been much discussed by social scientists but have not been given satisfactory statistical formulations. The results concern directed measures of associations in linear models containing just three variables. Some key words: Analysis of covariance; Analysis of variance; cG-distribution; Conditional independence; Graphical chain model; Parallel regressions; Yule-Simpson paradox. 1. INTRODUCTION Linear models are commonly used as a framework to estimate and test how a continuous response variable depends on potential influencing variables. This paper is concerned with the situation in which two influences are random variables as well, which may be discrete or continuous. The continuous random variables are to stand for quantitative properties of observational units, while the discrete variables either capture qualitative properties or they represent subgroups of the population to which the observational units belong. To think of all variables as random variables is usually appropriate for data obtained from observational studies, where one cannot control which levels or values of the influencing variables are to be observed. The linear model permits an analysis conditional on fixed levels and values of the influences. But frequently, the association structure among the influences is, in social science applications, of interest itself and, as it will turn out, it is important for a correct interpretation of how the response depends on the influences. Awareness of such problems in interpretation is widespread among social scientists as is documented by extensive discussions of moderating effects; see, for example, Saunders (1956), Zedeck (1971) and Baron & Kenny (1986). There, a variable is called a moderator if its presence changes the strength or direction of an association. However, methods recommended to social scientists for identifying moderating effects given in the above literature or by Cohen & Cohen (1983, pp. 310-4) have been shown to be seriously deficient (Wermuth, 1988). Thus, there is need for clarification. We treat the case of a potential discrete moderator variable and call its categories or levels the subgroups in the linear model. A moderating effect is closely tied to the notion of consistent results on an association (Wermuth, 1987). In the present context results are said to be weakly consistent if the associations within subgroups coincide in direction and strongly consistent if the associ- ations within subgroups coincide in direction and strength. This notion depends typically on the chosen measure of association. In linear models we look at directed measures of
On the n-parameter abstract Cauchy problem

Let Hi(i = 1, 2, …, n), be closed operators in a Banach space X. The generalised initialvalue problem of the abstract Cauchy problem is studied. We show that the uniqueness of solution u: [0, T1] × [0, T2] × … × [0, Tn] → X of this n-abstract Cauchy problem is closely related to C0-n-parameter semigroups of bounded linear operators on X. Also as another application of C0-n-parameter semigroups, we prove that many n-parameter initial value problems cannot have a unique solution for some initial values.
3D dual-virtual-pinhole assisted single particle tracking microscopy

We propose a novel approach for high-speed, three-dimensional single particle tracking (SPT), which we refer to as dual-virtual-pinhole assisted single particle tracking microscopy (DVPaSPTM). DVPaSPTM system can obtain axial information of the sample without optical or mechanical depth scanning, so as to offer numbers of advantages including faster imaging, improved efficiency and a great reduction of photobleaching and phototoxicity. In addition, by the use of the dual-virtual-pinhole, the effect that the quantum yield exerts to the fluorescent signal can be eliminated, which makes the measurement independent of the surroundings and increases the accuracy of the result. DVPaSPTM system measures the intensity within different virtual pinholes of which the radii are given by the host computer. Axial information of fluorophores can be measured by the axial response curve through the ratio of intensity signals. We demonstrated the feasibility of the proposed method by a series of experiments. Results showed that the standard deviation of the axial measurement was 19.2 nm over a 2.5 μm range with 30 ms temporal resolution.
Translatory MOEMS actuator and system integration for miniaturized Fourier transform spectrometers

Abstract. A translatory MOEMS actuator with extraordinary large stroke—especially developed for fast optical path length modulation in miniaturized Fourier transform infrared spectrometers (FTSs)—is presented. A precise translational out-of-plane oscillation at 500 Hz with large stroke of up to 1.2 mm is realized by means of an optimized MEMS design using four pantograph suspensions of the comparative large mirror plate with 5-mm diameter. The MOEMS device is driven electrostatically resonant and is manufactured in a CMOS compatible silicon-on-insulator process. Up to ±600 μm amplitude (typically 1 mm stroke) has been measured in vacuum of 30 Pa and 50 V driving voltage for an optimized pantograph design enabling reduced gas damping and higher driving efficiency. For FTS system integration, the MOEMS actuator has been encapsulated in a hybrid optical vacuum package. The thermal influences of packaging technology on MOEMS behavior are discussed in more detail.
The Euclidean, hyperbolic, and spherical spans of an open Riemann surface of low genus and the related area theorems

It was almost fifty years ago that M. Schiffer [11] introduced the notion of span to study the theory of conformal mapping—or the theory of univalent functions if one would like to call it—of multiply connected plane domains along the line of Grotzsch and Grunsky. The notion has since been playing an important role in the theory of conformal mapping of planar Riemann surfaces. To deal with nonplanar Riemann surfaces equally, we shall have to take account of holomorphic mappings (into other Riemann surfaces) as well as holomorphic functions, and also have to generalize the notion of span. While the study of holomorphic mappings in its full generality is still immature, the theory of conformal embeddings (—injective holomorphic mappings) suffices for our purposes. More specifically, if we confine ourselves to those mappings which embed an open Riemann surface of finite genus into closed ones of the same genus, considerably satisfactory results could be expected. We have shown some of them in the preceding papers [12]-[15], on which the present article is based. By the phrase "of low genus" we mean "either of genus zero or of genus one". We first consider the case of genus one. To state the preparatory facts briefly and clearly, it is convenient to introduce the term "an open torus", which simply means an open Riemann surface of genus one. Meanwhile we keep the classical terminology "a torus" means a closed Riemann surface of genus one as usual. Sometimes the term "a closed torus" will be also used for the same purpose. A compact continuation of an open torus is, roughly speaking, a conformal embedding of the open torus into a closed torus which induces the prescribed correspondence between their canonical homology bases. We have shown in [13], among other things, that the set of moduli of the compact continuations of an open torus is a closed disk in the upper half plane, and that the diameter of this moduli disk gives a close analogue of Schiffer's span. Although the present work has been motivated by the investigation of open tori, the method does work, in principle, also for planar Riemann surfaces and yields new results
Adiabatic nanofocusing of plasmons by sharp metallic grooves: Geometrical optics approach

In this paper, we demonstrate the possibility of efficient adiabatic nanofocusing of gap plasmons by sharp metallic V grooves or dielectric wedges covered with metal. The geometrical optics approach and the approximation of continuous electrodynamics are used for the analysis. In particular, it is demonstrated that both the phase and group velocities of an incident symmetric (with respect to the magnetic field) plasmon tend to zero at the tip of the groove, and the plasmon adiabatically slows down, eventually dissipating in the metal. The amplitude of the plasmon strongly increases near the tip of the groove. However, unlike nanofocusing by a sharp metal conical tip, even in the absence of dissipation, the amplitude of the plasmon near the tip of a V groove remains finite. The dependence of the maximal local-field enhancement on structural parameters, dissipation in the metal, angle of incidence, etc., is analyzed. It is also shown that a symmetric gap plasmon can effectively be guided by the groove, form.
Large-scale magnetic fields of low-mass dwarfs: the many faces of dynamo

Abstract Magnetic field are ubiquitous to low-mass stars and can potentially impact their evolution and their internal structure; yet the physical processes (called dynamo) that succeed at generating them in the stellar convective zones of cool dwarfs are still enigmatic. Although theoretical modelling and numerical simulations of stellar dynamo action showed breathtaking progress in the last decade, they are not yet in the state of accurately predicting the various magnetic topologies that different low-mass stars can generate. Thanks to the advent of new-generation instruments, spectropolarimetric observations can now reveal the large-scale magnetic topologies of cool dwarfs, from the brown dwarf threshold (spectral type M8) up to the limit beyond which outer convective zones get vanishingly small (spectral type F5). In particular, they can reconstruct through tomographic methods the poloidal and toroidal components of the large-scale field, hence offering a fresh option for guiding dynamo theories to a more mature state. We review here the latest observational advances, showing in particular that magnetic topologies of low-mass dwarfs can drastically vary with mass and rotation rate, and discuss their implications for our understanding of dynamo processes.
rf-microwave switches based on reversible semiconductor-metal transition of VO2 thin films synthesized by pulsed-laser deposition

Microwave switching devices based on the semiconductor-metal transition of VO2 thin films were developped on two types of substrates C-plane sapphire and SiO2 / Si, and in both shunt and series configurations. Under thermal activation, the switches achieved up to 30-40 dB average isolation of the radio-frequency rf signal on 500 MHz-35 GHz frequency band with weak insertion losses. These VO2-based switches can be electrically activated with commutation times less than 100 ns, which make them promising candidates for realizing efficient and simple rf switches.
Solar radiation‐induced changes in ionospheric height and the Schumann resonance waveguide on different timescales

This study draws together the available observations in the Schumann resonance frequency range to examine the general issue of sensitivity of ionospheric height variations to changes in ionizing radiation from the Sun on different timescales. Ionospheric height can be formally defined, and two characteristic heights are recognized in the Schumann resonance frequency range. In general, order of magnitude changes in radiation are needed to cause relative changes in ionospheric height as large as 10%, as is the case on both the diurnal and 11‐year timescales. Changes in EUV radiation are probably insufficiently strong to account for either the 27‐day or the 11‐year variation in ionospheric height. More ionization‐effective X radiation is needed, but much smaller height changes are expected on the solar rotation timescale because the variations in X radiation on this timescale are only tens of percent and not orders of magnitude. The annual variation in radiation from the Sun is only 7%, with an expected height variation less than 100 m, and this remains to be verified by observations. The general insensitivity of the Schumann resonance cavity to changes in ionizing radiation lends stability to the medium that is valuable toward quantifying absolute changes in the global lightning activity on various timescales within the cavity.
Pressure-supported Ionized Gas in S0 Galaxies

Rotation curves and velocity dispersion profiles are presented for both the stellar and gaseous components of a sample of S0 galaxies. In all galaxies the central velocity dispersion of the ionized gas exceeds 150 km s-1. In some galaxies the gas dispersion remains as high as the stellar one over an extended radial range, showing that random motions are crucial for the dynamical support of the gas. Such a pressure support may explain why the observed gas rotation curves in galaxy bulges often fall short of the circular velocity predicted from the stellar kinematic models. It is suggested that, in addition to the acquisition of external material, some of the observed gas in S0 galaxies may have been shed from bulge stars.
Double-negative dynamic properties in one-dimensional multi-phase metamaterial based on the symmetrical equivalent layer

Acoustic metamaterials have important potential applications in engineering by their unusual properties. Based on the concept of symmetrical equivalent layer, it is found that layered acoustic metamaterial which exhibits simultaneously negative effective modulus and density can be existed. By using the transfer matrix method, the continuous double-negative dynamic properties can be achieved through a multi-phase microstructure considering viscous damping, and the left-handed wave propagation property appears during the double-negative frequency regions. This will be a reference for the design of 1D acoustic negative refraction metamaterials.
A General Equation for the Terminal Fall Speed of Solid Hydrometeors.

Abstract A comprehensive yet simple formula is presented for the terminal fall velocity of solid precipitation particles. It depends on three particle parameters: mass, the mean circumscribed area presented to the flow, and the mean effective projected area presented to the flow. This formula is deduced from a single mean Davies number-Reynolds number relation based on boundary layer theory and therefore includes environmental conditions (air density and temperature). Terminal velocity is predicted with errors ≲10% for a wide variety of particles, e.g., various planar and columnar crystals, rimed and unrimed aggregates, graupel (lump, conical, and hexagonal) and hail up to over 10cm in diameter. In view of its general form and the broad base of examination, the formula is felt to be generally applicable to all kinds of natural solid precipitation particles including shapes not tested in this study.
An Efficient Algorithm for Discrete $l_1$ Linear Approximation with Linear Constraints

We describe an algorithm, based on the simplex method of linear programming, for solving the discrete $l_1$ approximation problem with any type of linear constraints. The numerical results reported here, combined with the fact that in the absence of constraints the present algorithm reduces to our earlier unconstrained $l_1$ algorithm, indicate that this algorithm is very efficient.
EMBEDDED DISC-TYPE SURFACES WITH LARGE CONSTANT MEAN CURVATURE AND FREE BOUNDARIES

Given Ω ⊂ ℝ3 an open bounded set with smooth boundary ∂Ω and H ∈ ℝ, we prove the existence of embedded H-surfaces supported by ∂Ω, that is regular surfaces in ℝ3 with constant mean curvature H at every point, contained in Ω and with boundary intersecting ∂Ω orthogonally. More precisely, we prove that if Q ∈ ∂Ω is a stable stationary point for the mean curvature of ∂Ω, then there exists a family of embedded -surfaces near Q, e > 0 small, which, once dilated by a factor and suitably translated, converges to a hemisphere of radius 1 as e → 0.
Gravitational Faraday effect in conformally stationary spacetimes

For conformally stationary spacetimes it is possible to formulate the geometric optics approximation of light propagation purely in terms of the geometry of the three-dimensional manifold M consisting of the integral curves of the conformal Killing vector field. In this framework they derive the transport law for the polarization plane in M. If the conformal Killing field has a non-vanishing twist, the polarization plane undergoes a rotation similar to the familiar Faraday rotation in a magnetic field. This so-called gravitational Faraday effect is of particular interest in the gravitational field of rotating matter where is is coupled to the angular momentum of this matter. Therefore, they illustrate their general results with three rotating matter examples, namely (i) an Ozsvath-Schucking spacetime; (ii) the gravitational field outside a rotating body and (iii) a Kerr black hole embedded into a Robertson-Walker cosmos. Thereby they roughly estimate the observability of the gravitational Faraday effect in solar system experiments and in connection with the gravitational lens effect.
Tropical Wave Instabilities: Convective Interaction with Dynamics Using the Emanuel Convective Parameterization

Abstract Wave-CISK and evaporation-wind feedback modes, also known as WISHE (wind-induced surface heat exchange) modes, are investigated using a two-dimensional (x−p), hydrostatic, nonrotational model linearized about a basic state in radiative-convective equilibrium with no vertical shear. Cumulus convection is parameterized using version 1.22 of the Emanuel convective parameterization scheme, a mass flux scheme that includes the effects of evaporatively driven unsaturated downdrafts. It is found that the only unstable modes are long-wavelength WISHE modes. All wave–CISK modes are damped, though the longest-wavelength modes have nearly neutral growth rates. It is demonstrated that the presence of evaporatively driven unsaturated downdrafts plays a major role in damping both short-wave WISHE and wave-CISK modes in the model. The model favors approximately the same horizontal scale as observed for the Madden–Julian oscillation (40–60 day wave), but the phase speed is too large by a factor of ∼4–5. A genera.
The Statistical Mechanics of Strategic Interaction

I study strategic interaction among players who live on a lattice. Each player interacts directly with only a finite set of neighbors, but any two players indirectly interact through a finite chain of direct interactions. I examine various stochastic strategy revision processes, including (myopic) best response and stochastic choice. I discuss both stationary distributions and the limit behavior of these Markov processes. Stationary distributions are partially characterized, and the asymptotic behavior of stochastic choice for those processes whose choice rule is nearly best-response is related to equilibrium selection in symmetric 2 × 2 and n × n coordination games. Journal of Economic Literature Classification Number: C78.
Comparison between length and velocity gauges in quantum simulations of high-order harmonic generation

We solve the time-dependent Schr\"odinger equation for atomic hydrogen in an intense field using spherical coordinates with a radial grid and a spherical harmonic basis for the angular part. We present the high-order harmonic spectra based on three different forms, the dipole, dipole velocity, and acceleration forms, and two gauges, the length and velocity gauges. The relationships among the harmonic phases obtained from the Fourier transform of the three forms are discussed in detail. Although quantum mechanics is gauge invariant and the length and velocity gauges should give identical results, the two gauges present different computation efficiencies, which reflects the different behavior in terms of characteristics of the physical couplings acting in the two gauges. In order to obtain convergence, more angular momentum states are required in the length gauge, while more grid points are required in the velocity gauge. At lower laser intensity, the calculation in the length gauge is faster than that in the velocity gauge, while at high laser intensity, the calculation in the velocity gauge is more efficient. The velocity gauge is also expected to be more efficient in higher-dimensional calculations.
Inter‐sample avoidance in trajectory optimizers using mixed‐integer linear programming

This paper proposes an extension to trajectory optimization using mixed‐integer linear programming. The purpose of the extension is to ensure that avoidance constraints are respected at all times between discrete samples, not just at the sampling times themselves. The method is very simple and involves applying the same switched constraints at adjacent time steps. This requires fewer additional constraints than the existing approach and is shown to reduce computation time. A key benefit of efficient inter‐sample avoidance is the facility to reduce the number of time steps without having to compensate by enlarging the obstacles. A further extension to the principle is presented to account for curved paths between samples, proving useful in cases where narrow passageways are traversed. Copyright © 2013 John Wiley & Sons, Ltd.