Miracle-dz/UniFAR-FTUs huggingface dataset:
Wave propagation and Thom's theorem

Scalar waves propagated from a finite emitter in an inhomogeneous medium form caustics whose geometry and location are functions of both the boundary conditions on the emitter and the inhomogeneity of the medium. The wave amplitude satisfies a Helmholtz equation. For the class of problems considered, a phase is derived from a characterisation of the medium and the boundary conditions on the emitter. The location and geometry of the caustic in configuration space is determined from phase space considerations through the Lagrange manifold. An oscillatory integral whose asymptotic expansion is that of the amplitude, is determined by a sharpening of Maslov's method (1972) of characteristics. Thom's theorem prescribes a normal form for the phase function in the integral. Transformations carrying the phase function to the canonical form are determined; then, following Duistermaat (1973), the complete asymptotic series of the integral, and hence of the amplitude, is obtained. The entire algorithm is illustrated with a specific example.
Measuring engagement effectiveness in social media

Social media is becoming increasingly prevalent with the advent of web 2.0 technologies. Popular social media websites, such as Twitter and Facebook, are attracting a gigantic number of online users to post and share information. An interesting phenomenon under this trend involves that more and more users share their experiences or issues with regard to a product, and then the product service agents use commercial social media listening and engagement tools (e.g. Radian6, Sysomos, etc.) to response to users' complaints or issues and help them tackle their problems. This is often called customer care in social media or social customer relationship management (CRM). However, all these existing commercial social media tools only provide an aggregated level of trends, patterns and sentiment analysis based on the keyword-centric brand relevant data, which have little insights for answering one of the key questions in social CRM system: how effective is our social customer care engagement? In this paper, we focus on addressing the problem of how to measure the effectiveness of engagement for service agents in customer care. Traditional CRM effectiveness measurements are defined under the scenario of the call center, where the effectiveness is mostly based on the duration time per call and/or number of answered calls per day. Different from customer care in a call center, we can obtain detailed conversations between agents and customers in social media, and therefore the effectiveness can be measured by analyzing the content of conversations and the sentiment of customers.
Laser light scattering in laboratory plasmas

The theory of light scattering from a collection of free electrons is reviewed, and it is shown that the frequency spectrum observed at a detector is precisely that of the density fluctuations of a particular scale length in the scattering medium, the scale length being determined by the wavelength of the incident light and the geometry of the experimental arrangement. The electron density fluctuation in a plasma is calculated, and it is shown that the plasma Debye shielding distance λD is a critical length in the theory, the electrons behaving independently on a scale shorter than λD and collectively on a scale longer than λD. The collective behaviour is characterized by the presence of waves that can give rise to well-defined resonances in the scattered-light spectrum. The effects of differing ion and electron temperatures, current flowing in the plasma, magnetic field, and Coulomb collisions are considered briefly. Technical considerations in planning experiments to test the theory and to apply it to the diagnosis of real laboratory plasmas are discussed, with attention being given to signal-to-noise ratio, stray light, and the dispersing instrument to be used at the detector. Some representative experiments that have been carried out are reviewed.
A new decentralized robust controller design for multi‐area load–frequency control via incomplete state feedback

This paper deals with load-frequency control of multi-area power installation. The robust control theory is utilized to decouple the areas for a decentralized robust load-frequency controller. The proposed controller ensures that the overall multi-area power system is asymptotically stable. A new technique is included to exclude feedback from any immeasurable state. The product comprises a set of local load-frequency controllers, one for each area. The design and operation of each local controller requires solely the corresponding area's parameters and state measurements. Measurements of the immeasurable states are unnecessary. System parameter uncertainties and generation rate constraints are included in the simulation study of three-area power system. Good results are reported.
Interface-induced phenomena in polarization response of ferroelectric thin films

This article reviews the existing theoretical models describing the interface-induced phenomena which affect the switching characteristics and dielectric properties of ferroelectric thin films. Three groups of interface-induced effects are addressed—namely, “passive-layer-type” effects, ferroelectric-electrode contact potential effects, and the poling effect of the ferroelectric-electrode interface. The existing experimental data on dielectric and switching characteristics of ferroelectric thin film capacitors are discussed in the context of the reviewed theories. Special attention is paid to the case of internal bias field effects.
Complete photonic band gaps and tunable self-collimation in the two-dimensional plasma photonic crystals with a new structure

In this paper, the properties of complete photonic band gaps (CPBGs) and tunable self-collimation in two-dimensional plasma photonic crystals (2D PPCs) with a new structure in square lattices, whose dielectric fillers (GaAs) are inserted into homogeneous and nomagnetized plasma background are theoretically investigated by a modified plane wave expansion (PWE) method with a novel technique. The novel PWE method can be utilized to compute the dispersion curves of 2D PPCs with arbitrary-shaped cross section in any lattices. As a comparison, CPBGs of PPCs for four different configurations are numerically calculated. The computed results show that the proposed design has the advantages of achieving the larger CPBGs compared to the other three configurations. The influences of geometric parameters of filled unit cell and plasma frequency on the properties of CPBGs are studied in detail. The calculated results demonstrate that CPBGs of the proposed 2D PPCs can be easily engineered by changing those parameters, and the larger CPBGs also can be obtained by optimization. The self-collimation in such 2D PPCs also is discussed in theory under TM wave. The theoretical simulations reveal that the self-collimation phenomena can be found in the TM bands, and both the frequency range of self-collimation and the equifrequency surface contours can be tuned by the parameters as mentioned above. It means that the frequency range and direction of electromagnetic wave can be manipulated by designing, as it propagates in the proposed PPCs without diffraction. Those results can hold promise for designing the tunable applications based on the proposed PPCs.
ELECTRICAL PERFORMANCE OF CHARGE INJECTION ELECTROSTATIC ATOMIZERS

The parametric evaluation of the variables that define the operation of a charge injection electrostatic atomizer is described in terms of the electrical performance. Here atomizer performance for smaller orifice diameters and more viscous liquids than previously investigated is presented. The response of the injected current as a function of atomizer geometry, coupled to an analysis of the empirical charge injection laws, is used to relate the electrohydrodynamics with more well-established studies in quiescent liquid. Evaluation of spray and leakage current to injection current ratios are also used to determine the electrical efficiency with a view to locating the optimum operating conditions as a function of atomizer geometry and applied bulk flow. The optimum electrode-to-orifice diameter ratio in previous work is confirmed, and the relationship between the spray specific charge and the maximum electric field on jet surface at a critical point of operation is extended to charge injection atomizers of small orifice diameter.
Second harmonic generation imaging of collagen matrix remodeling in a stimulated 3D cellular environment: forward versus backward detection

The structural remodeling of collagen is important in several biological processes such as wound healing, tendon repair, fibrosis and developmental morphogenesis. Multiphoton microscopy, which uses ultra-short femto-second laser pulses as an excitation source, is efficient in the multiphoton excitation fluorescence (MPEF) of exogenous fluorescent labels tagged to various cellular macromolecular objects, as well as in the induction of a highly specific second harmonic generation (SHG) signal from non-centrosymmetric macromolecules such as fibrillar collagens. Although the non-descanned detectors in the reflection geometry have normally been employed for capturing the backward scattered SHG as well as the MPEF signals, considering the wide range of engineered thick tissue imaging applications, there are still un-answered questions about the generated 3D collagen structures because of the directional pattern of SHG signals. The present study dealt with an in vitro collagen-fibroblast raft model in which the stimulation of fibroblast cells induced the lateral orientation of collagen molecules. The SHG signals originating from the 3D collagen matrix were captured simultaneously in both forward and backward scattering directions to understand the collagen structural differences and to generate a comprehensive understanding of collagen matrix remodeling.
A COMPARISON OF THREE METHODS FOR GENERATING THE PARETO OPTIMAL SET

This paper describes and compares three approaches to solving design optimization problems with multiple conflicting objectives. The three techniques are described in detail and then applied lo an example which demonstrates how information is accumulated which leads to a logical and efficient multicriteria optimal design. The techniques employed (weighting, noninferior set estimation and constraint methods) ate compared to each other by considering their computational efficiencies and their abilities to produce an approximation of the Pareto optimal set.
Performance highlights of the ALMA correlators

Two large correlators have been constructed to combine the signals captured by the ALMA antennas deployed on the Atacama Desert in Chile at an elevation of 5050 meters. The Baseline correlator was fabricated by a NRAO/European team to process up to 64 antennas for 16 GHz bandwidth in two polarizations and another correlator, the Atacama Compact Array (ACA) correlator, was fabricated by a Japanese team to process up to 16 antennas. Both correlators meet the same specifications except for the number of processed antennas. The main architectural differences between these two large machines will be underlined. Selected features of the Baseline and ACA correlators as well as the main technical challenges met by the designers will be briefly discussed. The Baseline correlator is the largest correlator ever built for radio astronomy. Its digital hybrid architecture provides a wide variety of observing modes including the ability to divide each input baseband into 32 frequency-mobile sub-bands for high spectral resolution and to be operated as a conventional 'lag' correlator for high time resolution. The various observing modes offered by the ALMA correlators to the science community for 'Early Science' are presented, as well as future observing modes. Coherently phasing the array to provide VLBI maps of extremely compact sources is another feature of the ALMA correlators. Finally, the status and availability of these large machines will be presented.
Intensity–phase characterization of white-light continuum generated in sapphire by 280 fs laser pulses at 1053 nm

A white-light continuum is generated in bulk sapphire using 280 fs, 1053 nm centre wavelength pulses at peak powers well above the critical power. The resulting spectrum extends from 400 nm up to at least 1100 nm with good conversion efficiency. A high-pass filter is used to remove the residual peak at the pump wavelength, producing a broad, flat spectrum in the near infrared region. We characterize the intensity and phase of the continuum by using cross-correlation frequency-resolved optical gating. We show that using pump pulses above 1 µm is a very interesting approach for generating broad continua with favourable characteristics.
Absolute proper motions to B approximately 22.5: Evidence for kimematical substructure in halo field stars

Radial velocities have been obtained for six of nine stars identified on the basis of similar distances and common, extreme transverse velocities in the proper motion survey of Majewski (1992) as a candidate halo moving group at the north Galactic pole. These radial velocities correspond to velocities perpendicular to the Galactic plane which span the range -48 +/- 21 to -128 +/- 9 km/sec (but a smaller range, -48 +/- 21 to -86 +/- 19 km/sec, when only our own measurements are considered), significantly different than the expected distribution, with mean 0 km/sec, for a random sample of either halo or thick disk stars. The probability of picking such a set of radial velocities at random is less than 1%. Thus the radial velocity data support the hypothesis that these stars constitute part of a halo moving group or star stream at a distance of approximately 4-5 kpc above the Galactic plane. If real, this moving group is evidence for halo phase space substructure which may be the fossil remains of a destroyed globular cluster, Galactic satellite, or Searle & Zinn (1978) 'fragment. '
Complex Behavior Recognition Based on Convolutional Neural Network: A Survey

Behavior recognition is an important research direction in computer vision. The behavior recognition based on convolutional neural network has become a research hotspot in recent years. The methods based on convolutional neural network can extract features directly from video data, reduce the difference of temporal domain and the influence of spatial complexity. At present, the simple behavior recognition based on convolutional neural network has been solved basically. However, the complex behavior recognition based on convolutional neural network still faces many difficulties. In this paper, the issues of spatial dependencies and time dependencies in complex behavior recognition are discussed. Then convolutional neural network applying to complex behavior recognition is analyzed in detail from time, space, and spatio-temporal aspects following research progress. Finally, the future development of complex behavior recognition based on convolutional neural network is indicated.
Setting limits on q0 from gravitational lensing

Gravitational lensing by galaxies in a wide variety of cosmological models is considered. For closed models, the lensing depends on the parameter beta(crit). If beta(crit) is greater than zero, a normal lensing case can be obtained with two bright images separated by an angle twice beta(crit) and a third, arbitrarily dim image between them coincident with the position of the lensing galaxy nucleus. As the QSO approaches the antipodal redshift, which can occur in models with large values of the cosmological constant, the cross sections for lensing blow up. An overfocused case where beta(crit) is less than zero can be obtained for a QSO beyond the antipodal redshift. In this case, when a lensing event occurs, only one arbitrarily dim image coincident with the position of the lensing galaxy nucleus is seen. If galaxy rotation curves are always flat or slowly rising, the overfocused case always produces one image. 33 refs.
Retrieval of the full magnetic vector with the He I multiplet at 1083 nm. Maps of an emerging flux region

A technique is presented to invert Stokes profiles of the He I 1083 nm multiplet lines in order to obtain the full magnetic vector and the line-of-sight velocity. The technique makes use of spectropolarimetry connected with the Zeeman effect supplemented by a simple Hanle effect based diagnostic when appropriate. It takes into account effects like line saturation, magnetooptical effects, etc. and is coupled with a genetic algorithm, which ensures that the global minimum in a goodness of fit hypersurface is found. Tests using both artificial and real data demonstrated the robustness of the method. As an illustration maps of deduced parameters of an emerging flux region are shown and briefly discussed.
Extended operational regimes and MHD behavior in a low-aspect-ratio reversed field pinch in RELAX

Operational regimes have been investigated over a wide range of discharge parameters in a low-aspect-ratio (low-A) reversed field pinch (RFP) RELAX. Two distinctive regimes have been identified, possibly characteristic to low-A RFP. One is a very shallow-reversal regime, and the other is an extremely deep-reversal regime where a field-reversal parameter lower than −1 could be sustained. In newly attained extremely deep-reversal plasmas, the amplitudes of the resonant modes were suppressed to a lower level with enhanced soft-x-ray emission intensity. The extremely deep-reversal regime in low-A RFP may have a potential to become a new operational regime with improved plasma performance.
THE TRANSPORT OF LOW-FREQUENCY TURBULENCE IN ASTROPHYSICAL FLOWS. I. GOVERNING EQUATIONS

Numerous problems in space physics and astrophysics require a detailed understanding of the transport and dissipation of low-frequency turbulence in an expanding magnetized flow. We employ a scale-separated decomposition of the incompressible MHD equations (based on an Elssässer description) and develop a moment hierarchy to describe the transport of the total energy density in fluctuations, the cross-helicity, the energy difference, and correlation lengths corresponding to forward- and backward-propagating modes and to the energy difference. The dissipation terms for the various transport equations are derived. One-point closure schemes are utilized. The technical elements of this work that distinguish it from previous studies are (1) the inclusion of the large-scale background inhomogeneous Alfvénic velocity VA at a level of detail greater than before, (2) the introduction of a tractable slow timescale closure to eliminate high-frequency interference terms that is likely to prove a useful approximation for practical problems related to the transport of turbulence in an inhomogeneous flow such as the solar wind or solar corona, and finally, (3) we develop a simplified phenomenology for the energy difference or equivalently residual energy that may be useful for practical applications. This yields a coupled system of six equations that describes the transport of turbulence in inhomogeneous sub-Alfvénic and super-Alfvénic flows. The turbulence transport equations are quasi-linear in their spatial evolution operators and nonlinear in the dissipation terms, making the model equations relatively tractable to analysis.
Local quasiparticle density of states in ferromagnet/superconductor nanostructures

We study the proximity effect in superconductor/ferromagnet $(S/F)$ systems and propose a detailed theoretical description of the damped-oscillatory behavior of the quasiparticle local density of states in a ferromagnet. It is demonstrated that impurities play a very important role in determining the amplitude and the shape of spatial and energy dependance of the density of states. Bearing in mind the possible comparison with experiments, we investigate different types of $S/F$ structures as well as temperature variation of the local density of states.
Electromagnetic Design, Fabrication, and Test of LPF1: A 10.2-T Common-Coil Dipole Magnet With Graded Coil Configuration

R&D of high-field accelerator magnets is ongoing at the Institute of High Energy Physics for the prestudy of high-energy accelerators in the future. As the first step, a 12-T subscale common-coil dipole magnet named Let the Proton Fly (LPF1) with two 7-mm apertures and graded coil configuration was designed, fabricated, and tested. With 4 NbTi double-pancake racetrack coils outside and 2 Nb3Sn double-pancake racetrack coils inside, this hybrid dipole magnet was designed to provide a 12-T main field in two apertures operating at 6100 A. The load line ratio is 83% @ 4.2 K for the designed current and field. To reduce the field enhancement at the ends of the coils, the coils were designed with different lengths. All of the six coils were wound with superconducting Rutherford cables and impregnated with epoxy CTD-101k. Bladders and keys technology was used to prestress coils during the assembly of LPF1. A 0.1 Ω dump resistor and a voltage-dependent varistor were used for the quench protection during the test of LPF1. LPF1 was tested at 4.2 K under the self-field and a field plateau was shown around 10.2 T after the 13th quench. The parameters of the design, process of the fabrication, and the test performance of LPF1 are presented in this paper.
Current generation with low-frequency waves

Various types of traveling waves may be injected into a tokamak to continuously sustain the toroidal current. Interest in this problem arises from the possibility of operating tokamak reactors in the steady state. The low‐frequency waves most suitable for this task are identified in terms of the power cost for deployment in a reactor. Means of exciting these waves and tradeoffs with design criteria are discussed. A comparison is made with the alternative attractive regime of high‐frequency waves. Conclusions are based, in part, on the numerical solution of the two‐dimensional Fokker–Planck equation with an added quasi‐linear term due to the waves.
The analysis of randomized experiments with orthogonal block structure. I. Block structure and the null analysis of variance

Nearly all the experimental designs so far proposed assume that the experimental units are or can be grouped together in blocks in ways that can be described in terms of nested and cross-classifications. When every nesting classification employed has equal numbers of subunits nested in each unit, then the experimental units are said to have a simple block structure. Every simple block structure has a complete randomization theory. Any permutation of the labelling of the units is permissible which preserves the block structure, and this defines a valid randomization procedure. In a null experiment all units receive the same treatment, and the population of all possible vectors of yields generated by the randomization procedure gives the null randomization distribution. The covariance matrix of this distribution, the null analysis of variance, and the expectations of the various mean squares in it are all derivable from the initial description of the block structure. All simple block structures can be characterized by a set of mutually orthogonal idempotent matrices Ci. Such sets of matrices may also exist for non-simple block structures (e. g. those having unequal numbers of plots in a block), and the existence of such a set defines an orthogonal block structure. Non-simple orthogonal block structures do not have a complete randomization theory and inferences from them require further assumptions.