Miracle-dz/UniFAR-FTUs huggingface dataset:
Two calibration procedures for a gyroscope-free inertial measurement system based on a double-pendulum apparatus

This paper presents a novel calibration algorithm to be used with a gyro-free inertial measurement unit (GF-IMU) based on the use of linear accelerometers (AC). The analytical approach can be implemented in two calibration procedures. The first procedure (P-I) is articulated in the conduction of a static trial, to compute the sensitivity and the direction of the sensing axis of each AC, followed by a dynamic trial, to determine the AC locations. By contrast, the latter procedure (P-II) consists in the calculation of the previously indicated calibration parameters by means of a dynamic trial only. The feasibility of the two calibration procedures has been investigated by testing two GF-IMUs, equipped with ten and six bi-axial linear ACs, with an ad hoc instrumented double-pendulum apparatus. P-I and P-II were compared to a calibration procedure used as a reference (P-REF), which incorporates the AC positions measured with an optoelectronic system. The experimental results we present in this paper demonstrate that (i) P-I is able to determine the calibration parameters of the AC array with a higher accuracy than P-II; (ii) consequently, the errors associated with translational (a0 − g) and rotational () acceleration components for the two GF-IMUs are significantly greater using P-II than P-I and (iii) the errors in (a0 − g) and obtained with P-I are comparable with the ones obtainable by using P-REF. Thus, the proposed novel algorithm used in P-I, in conjunction with the double-pendulum apparatus, can be globally considered a viable tool in GF-IMU calibration.
Effect of Surface Fluxes versus Radiative Heating on Tropical Deep Convection

AbstractThe effects of turbulent surface fluxes and radiative heating on tropical deep convection are compared in a series of idealized cloud-system-resolving simulations with parameterized large-scale dynamics. Two methods of parameterizing the large-scale dynamics are used: the weak temperature gradient (WTG) approximation and the damped gravity wave (DGW) method. Both surface fluxes and radiative heating are specified, with radiative heating taken as constant in the vertical in the troposphere. All simulations are run to statistical equilibrium.In the precipitating equilibria, which result from sufficiently moist initial conditions, an increment in surface fluxes produces more precipitation than an equal increment of column-integrated radiative heating. This is straightforwardly understood in terms of the column-integrated moist static energy budget with constant normalized gross moist stability. Under both large-scale parameterizations, the gross moist stability does in fact remain close to constant o.
On a set of polarized Kähler metrics on algebraic manifolds

A projective algebraic manifold M is a complex manifold in certain projective space CP, N > dim c M = n . The hyperplane line bundle of CP restricts to an ample line bundle L on M. This bundle L is a polarization on M. For the Kahler metric g on M, we can associate a positive, rf-closed (1, l)-form ωg . In any local coordinate system (Zj, , zn) of M , the metric g is expressed by a tensor (^/j)1</ 7-<fI, and ωg is defined to be ^^Σ" j=ι gqdzi Λ d~z. We call this ω the Kahler form associated to the metric g . By a polarized Kahler metric with respect to L, we mean a Kahler metric with its associated Kahler form representing the Chern class CX(L) of L in H (M, Z). We denote by Ka(M) the set of all polarized Kahler metrics on M with respect to L. Given a Kahler metric # in Ka(Af), one can find a hermitian metric h on L with its Ricci curvature form equal to ω (cf. [7], or Lemma 1.1 in §1). For each positive integer m > 0, the hermitian metric h induces a hermitian metric h on L m . Choose an orthonormal basis {STM9 ,S n N}of the space H°{M, L ) of all holomorphic global sec-
Transition and equilibration of neutral atmospheric boundary layer flow in one-way nested large-eddy simulations using the Weather Research and Forecasting Model

AbstractThe Weather Research and Forecasting Model permits finescale large-eddy simulations (LES) to be nested within coarser simulations, an approach that can generate more accurate turbulence statistics and improve other aspects of simulated flows. However, errors are introduced into the finer domain from the nesting methodology. Comparing nested domain, flat-terrain simulations of the neutral atmospheric boundary layer with single-domain simulations using the same mesh, but instead using periodic lateral boundary conditions, reveals the errors contributed to the nested solution from the parent domain and nest interfaces. Comparison of velocity spectra shows good agreement among higher frequencies, but greater power predicted on the nested domain at lower frequencies. Profiles of mean wind speed show significant near-surface deficits near the inflow boundaries, but equilibrate to improved values with distance. Profiles of the vertical flux of x momentum show significant underprediction by the nested dom.
Camera calibration using multiple sheets planar pattern

Camera calibration is a necessary step in 3D vision measurement. Classic technique uses a volume calibration pattern with control points distributing in a 3D space, which is expensive to be made and difficult to be used everywhere. Zhang proposed a planar pattern based calibration method, making the calibration process accessed to almost everyone. Nowadays, consume camera with zoom lens is populated and always used for measurement. Such a camera has the advantage to zoom the lens to get a maximum resolution images for objects with different sizes at an adequate distance. The size of Zhang's planar pattern is fixed, not suitable for a zoom lens. In this paper, a multiple sheets planar pattern is used to deal with this situation. The calibration pattern is made of 1-4 sheets of planar pattern distinguished with coded markers, and the total size . can be modified by changing the distance between the planar sheets or the number of sheets to suit for different lens setting. Such composed calibration pattern is easy used both for laboratory and industrial situation. In the calibration process, one sheet of the planar pattern is first used to get an initial calibration according Zhang's method, and also the initial coordinates of all the control points in the sheets of planar patterns. Then a bundle adjustment algorithm is carried out incorporating of the planar constraints and distance constraints in the planar patterns to obtain a set of precision parameters. Some examples are presented to show the effeteness of the method.
Observations of active-chromosphere stars – I. Spectroscopic study of AB Dor and PZ Tel

Observations spectroscopiques a haute resolution des etoiles de type avance, en rotation rapide AB Dor et PZ Tel. Ces 2 etoiles apparaissent chromospheriquement actives avec une forte raie K de CaII en emission et une raie Hα pratiquement remplie. Les vitesses radiales sont calculees pour chacune d'entre elles
Scanning potentiometry and magnetic imaging of current transport in high-temperature superconductor coated conductors

Second generation Y1Ba2Cu3O7-δ (YBCO) coated conductors promise greater performance than first generation powder-in-tube technology. Along with the development of these materials, advances in characterization techniques have enabled detailed studies of current flow, grain boundaries and homogeneity. We have developed a scanning probe system which can be configured to map either the magnetic field or electric potential at the sample surface (with a local Hall sensor or voltage probe respectively). While the magnetic image can be used to determine the current flow pattern, the potential map allows direct measurement of the local dissipation within the samples.
Revolution Speed Characteristics of an Ultrasonic Motor Estimated from the Pressure Distribution of the Rotor

Using a two-dimensional elastic contact theory, the pressure distribution on the area of contact between the rotor and the stator vibrator of an ultrasonic motor is calculated. In this calculation, the stator vibrator and the rotor are assumed to be a rigid body and an elastic half-space, respectively. The no-load revolution speed of the motor using the calculated pressure distribution is estimated, and is compared with the measured speed. As a result, it is proved that the revolution speed can be estimated by using the calculated pressure distribution if the assumption is satisfied.
Detecting surface oil slicks using VIIRS nighttime imagery under moon glint: a case study in the Gulf of Mexico

Using data collected over the Gulf of Mexico during night between May 2012 and September 2013 by the Visible Infrared Imager Radiometer Suite (VIIRS), we demonstrate a new application from its day-and-night band (DNB). Under cloud free and moon glint conditions, the DNB revealed surface oil slicks from natural oil seeps. This is despite the fact that the signal-to-noise ratio (SNR) of this wide band (505–890 nm) under moon glint is much lower (30:1–50:1) and its resolution is also coarser (750 m) than the VIIRS imaging bands (375 m) under daytime solar illumination. The DNB was designed to map light sources at night. Similar to its predecessor, the Defense Meteorological Satellite Program Operational Linescan System (OLS), the VIIRS DNB should be suitable to identifying bioluminescence at night. However, with its finer resolution and higher SNR than OLS, the VIIRS DNB is demonstrated here to be also able to complement other sensors in the detection and mapping of oil spills.
CROSS-COUNTRY HIERARCHICAL STRUCTURE AND CURRENCY CRISES

Using data from a sample of 28 representatives countries, we propose a classification of currency crises consequences based on the ultrametric analysis of the real exchange rate movements time series, without any further assumption. By using the matrix of synchronous linear correlation coefficients and the appropriate metric distance between pairs of countries, we were able to construct a hierarchical tree of countries. This economic taxonomy provides relevant information regarding liaisons between countries and a meaningful insight about the contagion phenomenon.
The optical and electrical properties of silver nanowire mesh films

We present experimental results for the transmission T, haze H, sheet resistance Rs, and its spatial fluctuations ΔRs for silver nanowire films. Mie light scattering theory of nanowires is developed to predict both T and H as a function of diameter D of wires and the surface fraction ϕs covered by the wires. Percolation theory is used to derive an equation for Rs in terms of D, the aspect ratio of wires D/L and ϕs. The critical exponent t for percolation of Rs is found to be 1.23 in close agreement with theoretical results for 2D random resistive networks (t = 1.3). These equations show the importance of both the distributions of diameter ⟨D⟩ and aspect ratio of wires ⟨D⟩⟨L⟩/⟨L2⟩ to predict the optical and electrical properties. Spatial fluctuations ΔRs/Rs can also be significant in these films and be greater than 10% as ϕs approaches the critical percolation concentration ϕc. We show that the calculated T versus Rs and H versus Rs curves are in good agreement with the experimental data. We propose figure.
Effects of sea‐ice ridges on sound propagation in the Arctic Ocean

An environmental/acoustic model of sound propagation in the Arctic Ocean, which accounts for reflection losses from ridged sea ice, has been developed. In this model sea‐ice ridges are represented as infinitely long, randomly distributed, elliptical half‐cylinders. Under‐ice reflection losses for acoustic wavelengths either large or small compared to ridge dimensions are computed from theoretical equations as a function of average keel depth and width, number of ridges/km, and grazing angle. Numerical values of under‐ice reflection loss as a function of grazing angle are then incorporated into ray‐theoretical computations of transmission loss assuming a single sound‐ speed profile which is characteristic of the central Arctic Ocean. The validity of the concepts and approximations, the limitations of the model, and the accuracy of coincident measurements of environmental and acoustic parameters required to validate the model are discussed. To illustrate the predictions and accuracy of the model under diver.
Application of Scanning Probe Microscopy to Genetic Analysis

We are developing an integrated technique involving of nanometer-size dissection of chromosome fragments by atomic force microscopy (AFM) and direct detection of the location of genome library clones by scanning near-field optical/atomic force microscopy (SNOM/AFM). The locations of nucleus organizer regions (NORs) on barley chromosomes and a bacterial artificial chromosome (BAC) clone were successfully detected by SNOM/AFM. Nanometer-scale dissection of silkworm pachytene chromosomes was also performed by AFM, and we succeeded in three successive dissection events of the chromosome region approximately 250 nm apart from each other. If this type of integrated method can be established in the near future, we will easily obtain the nucleotide sequences with positional information on chromosomes, which lead to a time- and cost-saving genome analysis technique.
Multi‐variate t Autoregressions: Innovations, Prediction Variances and Exact Likelihood Equations

Abstract. The multi‐variate t distribution provides a viable framework for modelling volatile time‐series data; it includes the multi‐variate Cauchy and normal distributions as special cases. For multi‐variate t autoregressive models, we study the nature of the innovation distribution and the prediction error variance; the latter is nonconstant and satisfies a kind of generalized autoregressive conditionally heteroscedastic model. We derive the exact likelihood equations for the model parameters, they are related to the Yule–Walker equations and involve simple functions of the data, the model parameters and the autocovariances up to the order of the model. The maximum likelihood estimators are obtained by alternately solving two linear systems and illustrated using the lynx data. The simplicity of these equations contributes greatly to our theoretical understanding of the likelihood function and the ensuing estimators. Their range of applications are not limited to the parameters of autoregressive models; in fact, they are applicable to the parameters of ARMA models and covariance matrices of stochastic processes whose finite‐dimensional distributions are multi‐variate t.
Two novel architectures for the self adaptive separation of signals

It is known that self-adaptive separation of a linear mixture of non-Gaussian independent signals can be achieved with a feedback structure that is adapted by the Jutten-Herault algorithm. Two novel architectures are presented. The first one is direct (no feedback). The second one is a mixed architecture, where a feedback structure is cascaded after a direct structure. Equlibrium points and their stability conditions are investigated for two mixed signals. The direct architecture is more general than the feedback one in that it involves no implementation constraints. It converges faster when there is an even number of minus signs in the mixture matrix. The mixed architecture's transient period is hardly dependent on the mixture matrix. Computer simulations corroborate the theory. <<ETX>>
Multiple-watermarking scheme for still images using the discrete cosine transform and modified code division multiple-access techniques

A modified code division multiple-access (MCDMA) technique is constructed by the spread-spectrum technique and a mix coder, and then it is used to configure a multiple-watermarking scheme for still images. Another type of multiple-watermarking scheme, non-code-division multiple-access watermarking (NCMW), is used to demonstrate that the MCDMA scheme is superior. In the embedding process, three watermark bits are modulated to the five-bit MCDMA code. Then the 15 MCDMA bits are concealed in the coefficients of a group that consists of four DCT blocks. Empirical results show that our proposed scheme can sustain attacks like JPEG lossy compression, rotation, resizing, cropping, painting, noising, and blurring. Compared with other multiple-watermarking schemes, our proposed method has two advantages: (1) The secret image has very high security owing to the use of MCDMA for digital communication. (2) The extracted watermarks have the same quality under all kinds of attacks, whereas other schemes yield different extracted-watermark quality.
Publications of the Astronomical Society of the Pacific 93:581-586, October 1981 SPECTRAL PROPERTIES OF NOVA LMC 1977b

Spectra obtained of Nova LMC 1977b have been reduced and analyzed. An expansion velocity of 625 km sec from the absorption lines of the principal spectrum was observed 1.16 days after maximum. From the emission profiles of Ha and [Ol] A6300 an expansion velocity of 1400 km sec was observed 13.5 days after maximum. Our spectral data and previously published photometry provide us with the following estimates: mass loss rate ~ 10 gm sec, photospheric radius æ 10 cm, and total energy released by the nova 8.10 ergs.
Anisotropic Two-Dimensional Friedel Oscillations

Scanning tunneling microscopy at 4K shows highly anisotropic screening charge density oscillations on Be(10{ovr 1}0) in the vicinity of surface defects and steps. The forms of these oscillations, which derive from the Friedel oscillations, can be directly related to the two-dimensional band structure of the surface (two electron pockets at the boundary of the surface Brillouin zone). Simple calculations show that the Friedel oscillations in such a case will contain major contributions from wavelengths which do not correspond to any Fermi wave vector. {copyright} {ital 1997} {ital The American Physical Society}
Characterisation of Raman gain spectra in Yb:YAG-derived optical fibres

For the first time, Raman gain spectra are measured for three all-glass Yb:YAG crystal-derived optical fibres. It is shown that fibres derived from YAG have a reduced Raman gain relative to that of pure silica, partly because of a significant broadening of the silica Raman lines, and also partly because of yttria and alumina possessing a lower gain than that of silica. Such a designer-materials approach for suppression of stimulated Raman scattering can enable future high-energy and high-peak-power fibre laser systems.
MBE growth of Sb-based type-II strained layer superlattice structures on multiwafer production reactors

Ga(In)Sb/InAs-based strained-layer superlattices (SLS) have received considerable attention recently for their potential in infrared (IR) applications. These heterostructures create a type-II band alignment such that the conduction band of InAs layer is lower than the valence band of Ga(In)Sb layer. By varying the thickness and composition of the constituent materials, the bandgap of these SLS structures can be tailored to cover a wide range of the mid-wave and long-wave infrared (MWIR and LWIR) absorption bands. Suppression of Auger recombination and reduction of tunneling current can also be realized through careful design of the Type-II band structure. The growth of high-quality Ga(In)Sb/InAs-based SLS epiwafers is challenging due to the complexity of growing a large number of alternating thin layers with mixed group V elements. In this paper, the development of a manufacturable growth process by molecular beam epitaxy (MBE) using a multi-wafer production reactor will be discussed. Various techniques were used to analyze the quality of the epitaxial material. Structural properties were evaluated by high-resolution x-ray diffraction (XRD) and cross-sectional transmission electron microscopy (XTEM). Optical properties were assessed by low-temperature photoluminescence measurements (PL). Surface morphology and roughness data as measured by Nomarski optical microscope and atomic force microscope (AFM) will be presented. Device characteristics such as dynamic impedance, responsivity, quantum efficiency, and J-V characteristics of photodiodes fabricated using our SLS epiwafers will be discussed.
Segmentation tools in mathematical morphology

This paper presents a general methodology for picture segmentation using tools provided by mathematical morphology. This methodology is based on the marking of the objects to be segmented. The marking (using techniques which may differ according to the kind of picture to be analyzed) provides a " marker set" which is used to modify the gradient of the image. This modification using geodesic image reconstruction produces a new gradient image. The main characteristic of this modified gradient is that its minima exactly fit the various connected components of the " marker set" . In a second step a morphological transform called " watersheds" is performed on this gradient image. The watershed transform produces a partition of the image into homogeneous regions called " catchment basins" . Every catchment basin contains only one marker and its boundary corresponds to the pixels of the image where the contrast is locally maximum. Thus the transformed image exhibits the contours of the marked objects. Some examples illustrate the use of this process when objects marking is not too complex. Then we extend this method to situations where the marking step is not obvious and we show how the watershed transform together with the simplification of the image can provide efficient tools for detecting homogeneous regions in an image.
Quantization as a consequence of the symmetry group: An approach to geometric quantization

A method is proposed to obtain the dynamics of a system which only makes use of the group law. It incorporates many features of the traditional geometric quantization program as well as the possibility of obtaining the classical dynamics: The classical or quantum character of the theory is related to the choice of the group, avoiding thus the need of quantizing preexisting classical systems and providing a group connection between the quantum and classical systems, i.e., the classical limit. The method is applied to the free‐particle dynamics and the harmonic oscillator.
Effects of aerosol optical depth and single scattering albedo on surface UV irradiance

Spectral measurements of solar global and direct UV irradiance are routinely conducted at Thessaloniki, Greece with a double monochromator Brewer spectroradiometer. From absolutely calibrated direct and global irradiance spectra, aerosol optical depth and diffuse irradiance spectra between 300 nm and 365 nm are derived. The modification of the global and diffuse irradiance and of the relationship between direct and diffuse irradiance by the aerosol single scattering albedo (SSA) is investigated with respect to aerosol optical depth and solar zenith angle using radiative transfer model calculations. Model calculations were used also to investigate the effect of SSA on the radiance distribution in the ultraviolet. The model-derived relations are compared with measurements, with the aim to establish an indirect method of deriving an effective single scattering albedo from spectral measurements of the direct and global irradiance. The uncertainties introduced by different sources into the SSA estimates are discussed. Finally the effective SSA is determined for two days with different aerosol amounts and composition. The overall accuracy in determining indirectly the SSA depends strongly on the amount of aerosols varying between 0.1 and 0.2 units of SSA.