Miracle-dz/UniFAR-FTUs huggingface dataset:
Measurement of Light attenuation in dense fog conditions for FSO applications

Free Space Optics (FSO) has gained considerable importance in this decade of demand for high bandwidth transmission capabilities. FSO can provide the last mile solution, but the availability and reliability issues concerned with it have acquired more attention, and a need for thorough investigations. In this work, we present our results about fog attenuation at the 950 and 850 nm wavelengths in heavy maritime fog with peak values up to 500 dB/km. For the attenuation measurement, optical wavelengths are transmitted over the same path of fog in free air to a receiver, measuring the power of every wavelength. The RF marker technology employed takes advantage of modulating every optical wavelength with an individual carrier frequency, allowing to use one optical front end for the receiver and to separate individual wavelengths by electrical signal filters. The measurement of fog attenuation at different wavelengths was performed at the France Telecom R & D test facility at La Turbie. Maritime or advection fog, which caused the light attenuation consists of water droplets of larger diameter in the order of 20 μm and can cause visibilities as low as 30 meters. The visibility was measured using a transmissiometer at 550 nm. We compare our measurement data with the commonly used light attenuation models of Kruse and Kim, and present some interesting insights. The practical measurements described try to validate the models and therefore should lead to a more accurate availability prediction for FSO links.
Semiconductor Thermochemistry in Density Functional Calculations

The local-density and generalized gradient approximations (LDA and GGA) to density functional theory (DFT) exhibit incomplete error cancellation when energy differences are taken between chemically dissimilar systems. This energy inconsistency is manifested, e.g., in the tendency to underestimate the heat (enthalpy) of formation of semiconducting and insulating compounds in LDA and, even more so, in GGA. Considering a set of 61 compounds that can be formed from 14 elements (cations: Cu, Mg, Ca, Zn, Cd, Al, Ga, and In; anions: N, P, As, O, S, and Se), optimized elemental reference energies are determined by least-squares error minimization of an overdetermined set of linear equations. These elemental energies are 'optimally consistent' with the DFT energies of the semiconductor compounds and imply corrections of up to 1 eV compared to the respective LDA or GGA energies. While these 'corrections' are not to be understood to yield the correct absolute total energies of the elements, they are proposed to give appropriate bounds for the chemical potentials for thermodynamic processes in semiconductors and insulators, such as, e.g., defect formation, surface reconstruction, or catalytic processes. The present model allows to evaluate thermodynamic processes using DFT energy differences taken only between systems that are expected tomore » show good error cancellation. « less
Stellar to Substellar Model Atmospheres

Abstract The spectral transition from Very Low Mass stars (VLMs) to brown dwarfs (BDs) and planetary mass objects (Planemos) requires model atmospheres that can treat line, molecule, and dust-cloud formation with completeness and accuracy. One of the essential problems is the determination of the surface velocity field throughout the main sequence down to the BD and planemo mass regimes. We present local 2D and 3D radiation hydrodynamic simulations using the CO5BOLD code with binned Phoenix gas opacities, forsterite dust formation (and opacities) and rotation. The resulting velocity field vs depth and Teff has been used in the general purpose model atmosphere code Phoenix, adapted in static 1D spherical symmetry for these cool atmospheres. The result is a better understanding of the spectral transition from the stellar to substellar regimes. However, problems remain in reproducing the colors of the dustiest brown dwarfs. The global properties of rotation can change the averaged spectral properties of these objects. Our project for the period 2011-2015 is therefore to develop scaled down global 3D simulations of convection, cloud formation and rotation thanks to funding by the Agence Nationale de la Recherche in France.
The photoevaporation of interstellar clouds. I: Radiation-driven implosion

An approximate analytical solution is developed for the evolution of an interstellar neutral cloud exposed to the ionizing radiation of a newly formed star. The structure of a steady photoevaporation gas flow off a spherical ionization front is derived even for cases where the ionization front cannot be considered thin, and the downstream flow is not in ionization and thermal equilibrium. Under a wide range of conditions, the ionization front is approximately D-critical, and the ionized gas expands supersonically into the intercloud medium. The ionization front typically drives a strong shock into the initial cloud.
Euclidian Monopoles and Rational Maps

A famous theorem of Donaldson describes a correspondence between SU(2) monopoles over three‐dimensional Euclidean space and maps from CP1 to itself. This paper generalises this to monopoles with arbitrary gauge group G, and new maps from CP1 to flag manifolds G/H are produced. This is in line with a conjecture of Atiyah and Murray, following a similar result of Atiyah's on hyperbolic monopoles.
Three-Dimensional Kinematic and Microphysical Evolution of Florida Cumulonimbus. Part III: Vertical Mass Transport, Mass Divergence, and Synthesis

Abstract A statistical technique is employed to examine the evolving properties of the ensemble small-scale variability of high-resolution radar data collected in a multicellular Florida thunderstorm. This paper examines vertical mass transport and mass divergence and synthesizes these observations with results from the first two parts of the study into a self-consistent conceptual model that describes the convective-to-stratiform transition of the storm. Vertical mass transport distributions indicate that the more numerous weak and moderate-strength upward and downward velocities, not the few strongest, accomplished most of the vertical mass transport in the storm. Hence, most of the mass of precipitation is condensed outside the areas of intense upward motion. These data thus suggest a change in the way we think about convection. Although the few regions of strongest vertical motion play a part in the overall storm evolution by dispersing particles throughout the depth of the storm, it is the more preva.
On the Coefficients of Irreversible Processes in a Highly Ionized Gas

An effective interparticle potential, which is a modified Debye-Huckel potential, is introduced and discussed in order to eliminate simultaneous interactions between three particles or more in an ionized gas. For this potential weak-interaction asymptotes of collision cross sections necessary for the theory of irreversible processes are calculated without making further approximations. These cross sections are applied to relaxation between ion and electron temperatures and to the coefficient of viscosity.
Liquid metals and plasmas as nucleus-electron mixtures

Liquid metals and plasmas are treated as binary mixtures of nuclei and electrons. The thermodynamic potential for the inhomogeneous system caused by fixing one of the nuclei in the mixture is constructed by associating it with a non-interacting ion-electron mixture as a reference system to describe this nucleus-electron mixture. With the use of the hypernetted chain (HNC) approximation, the Kohn-Sham-Mermin formalism based on this leads to a set of integral equations for the correlation functions: this set of integral equations also determines the average nuclear charge of the ion, the electron-ion potential and the electronic bound energy levels in a self-consistent manner, and thus becomes identical to the HNC equation for the ion-electron mixture. The electron-ion direct correlation function determined by these equations is shown to be equivalent to a pseudopotential introduced by Dagens et al. (1975) to take account of the non-linear effects. The conditions for the validity of the various conventional plasma theories, including the problem of estimating the average ionisation, are discussed in view of the present theory.
Equilibrium Flows in Non‐linear MHD Simulations of X‐point Plasmas

In non‐linear MHD simulations of ELMs [1], a radially localised, toroidally symmetric, poloidal flow layer exists in the H‐mode pedestal region. This sheared flow layer could have a significant influence on the linear stability properties of MHD instabilities and their non‐linear evolution. Using the non‐linear MHD simulation code JOREK [1] with reduced resistive MHD equations, we study the edge‐localised poloidal flow in both circular and X‐point tokamak plasmas at equilibrium (toroidal symmetry). For the circular case, an analytical interpretation is derived. In the simulations of X‐point plasmas, the flow can have both m = 0 and m = 1 components. In fact, abrupt transitions take place between the two equilibrium states, accompanied by a strong increase in the kinetic energy. Similar transitions between equilibrium flow states have been predicted by Strauss [2] for m = 0 poloidal flow patterns. Scalings are obtained for both the m = 1 and m = 0 flows.
Mutual-Coupling Compensation in Time-Modulated Antenna Arrays for Flat-Top Pattern Synthesis

Abstract A method that can be used to compensate for the mutual-coupling effect in time-modulated antenna arrays for synthesizing flat-top patterns is proposed in this article. Based on the measured complex embedded element patterns, the differential evolution algorithm is employed to optimize time sequences and phase excitation of each element in the array and to suppress the sideband level, leaving the amplitude excitations to be uniform. A −20-dB sidelobe level flat-top pattern is successfully synthesized in which the ripple level of the mainlobe is lower than 0.5 dB and the sideband level is lower than −10 dB. An S-band eight-element printed dipole with a double-layered structure linear array is used in the experiment to verify the proposed method, and the measured results are in good agreement with the simulated results.
Resonant two-photon ionization of atoms via two coupled Rydberg series

We present non-perturbative ab initio calculations of resonant two-photon ionization in which the ground state of a complex atom is resonantly coupled by a laser field to two Rydberg states, each of which belongs to a different Rydberg series. As an example, we have studied the resonant two-photon ionization of neon via the 5s and 4d Rydberg states using the R-matrix-Floquet theory. We find that for weak fields, where the Rydberg states are not overlapping, interference effects are already present which lead to a suppression of ionization for a particular laser frequency. For strong fields, the field induced coupling between the two Rydberg states can strongly modify the weak-field behaviour. We give a qualitative explanation of these phenomena by considering the dressed states of a simple three-level model atom coupled to two continua. Finally we show, by varying the intensity, how the Floquet eigenstates corresponding to the ground state and the two Rydberg states of neon are adiabatically connected to the field-free states.
The operational land imager: spectral response and spectral uniformity

The Landsat Data Continuity Mission (LDCM) will carry the Operational Land Imager (OLI) as one of its payloads. This instrument is a derivative of the Advanced Land Imager (ALI), flown on Earth Observing-1 (EO1) though it's mission is to continue the operational land imaging of the Landsat program. The OLI follows the highly successful Landsat-5 and Landsat-7 missions in continuing to populate an archive of earth images that dates back to 1972. The OLI has significant changes from the Landsat Thematic Mapper instruments, given that is the first pushbroom instrument in the program. However, it is intended to be a continuity mission, so the spatial coverage and spectral bands are similar. The suite of OLI's multispectral bands cover the same bandpasses but the panchromatic band is narrower than that of the ETM+. The OLI also has a shorter wavelength blue band for better resolution of coastal waters and a new band to aid in the detection of Cirrus clouds in the atmosphere. The thermal bands traditionally carried on the TM instruments have been moved to a separate instrument, also onboard the LDCM spacecraft. With the pushbroom design, each OLI multi-spectral band consists of nearly 7000 detectors. The OLI underwent prelaunch to verify a host of requirements on it's spectral performance, where was characterized at three different points during development. This paper will cover the results of the tests that attempt to validate the spectral uniformity requirements, including in-band response, out-of-band response, and spectral uniformity across the focal plane.
ERACS Method as a Solution to Allow Hospital and Patient Financing

ERACS (Enhanced Recovery After Caesarian Surgery) is a fast post-SC recovery program, namely a series of treatments starting from preoperative preparation, during surgery, and postoperative care to patient discharge. The ERACS concept is the development of the Enhanced Recovery After Surgery (ERAS) concept, where the ERAS concept was originally used in digestive surgery. The purpose of this study was to find out whether the eracs method could be used as a solution to ease the burden on hospital and patient costs. This research method was carried out using a literature review approach with a library approach. The nature of the research used in this research is a prescriptive design. The results of this study were then analyzed qualitatively. Based on the results of the study it can be concluded that the Enhanced Recovery After Caesarean Surgery (ERACS) method is the newest method performed for cesarean delivery. This method emphasizes reducing the anesthetic dose so that the patient does not need to spend a long time in the hospital. Because, if the patient stays in the hospital for too long, this will have an impact on increasing the cost of hospitalization. This method can reduce the financial burden on both patients and healthcare facilities. This will help a mother to care for her baby much earlier without compromising her safety and satisfaction. Hospitals will have an advantage in terms of decreased beds and thus the number of patients treated will increase and healthcare resources will be increased efficiently used.
Image Segmentation by Pre-Labeling Based on Part-Based Model

Interactive segmentation with graph cuts has become very popular and many priors have been introduced into graph cuts to improve the results. This paper proposed a method which uses the deformable part-based model to pre-label the seeds. First the deformable part-based model finds out the bounding box, then we can pre-label the seed point based on the assumption of compact shape. Our results show that our method can get more accurate result especially the appearance of the object and background are similar and the shape is compact.
The Identification of Individual Hygroscopic Particles in the Atmosphere by a Phase‐Transition Method

It is shown that in many cases the measurement of the relative humidity at which a hygroscopic particle becomes liquid can be used to establish the chemical composition of the particle. An apparatus is described which produces a stream of air of constant temperature and variable humidity. Using this apparatus the phase‐transition point was determined for particles collected on spider webs. These particles were sampled in the Sydney area on the ground and from an aircraft, and it is shown that the measured values of relative humidity for the solid‐liquid phase transition agreed with the hypothesis that the hygroscopic particles were composed of sea salt. Direct microscopic observation was used to follow the behavior of the particles; the technique was capable of dealing with particles down to 10−12g.
Universal Greenberger-Horne-Zeilinger-state analyzer based on two-photon polarization parity detection

We present a universal analyzer for the three-particle Greenberger-Horne-Zeilinger (GHZ) states with quantum nondemolition parity detectors and linear-optics elements. In our scheme, all of the three-photon GHZ states can be discriminated with nearly unity probability in the regime of weak nonlinearity feasible at the present state of the art experimentally. We also show that our scheme can be easily extended to the analysis of the multi-particle GHZ states.
Estimating the Tire–Pavement Grip Potential From Vehicle Vibrations

This study was motivated by the desire to provide highway managers/operators with more frequent and spatially dense information about the prevailing friction conditions in their networks. A new data-driven method was outlined for this purpose, wherein the prevailing tire–pavement grip potential is estimated from vehicle vibrations recorded during normal/regular usage of the infrastructure. The method was based on the underlying premise that transverse vehicle accelerations are related to wheel side-force oscillations, and therefore carry information related to the ride surface texture. It involved performing a short-time Fourier transform over vibration signals and analyzing the resulting spectral amplitudes. Two field experiments were carried out to validate the method. The first provided evidence of a statistical link between transverse vehicle vibrations and wheel side-force oscillations. The second tested the statistical link between skid resistance measured over a 26 km highway section and corresponding skid resistance estimations based on vehicle vibration data. Overall, transverse vehicle vibration characteristics were found to hold relevant information about the prevailing tire–pavement grip potential; the two were moderately inter-correlated. The newly proposed estimation method seems promising and potentially useful for pavement management applications, especially when considering the emergence of connected car technologies and the increased availability (and affordability) of in-vehicle Internet of Things devices.
Admissibility of unbounded control operators

For linear systems described by $\dot x(t) = Ax(t) + Bu(t)$, where A generates a semigroup on the state space X and B is an unbounded operator, some necessary as well as some sufficient conditions are given for B to be admissible, i.e., for any t, the state $x(t)$ should be in X and should depend continuously on the input $u \in L^p $. This approach begins with an axiomatic description of such a system in terms of a functional equation. The results are applied to the wave equation on a bounded interval.
Military expenditures and human capital development in sub-Saharan Africa: a system GMM approach

ABSTRACT This study investigates the military outlays effects on human capital development in sub-Saharan Africa. By using panel data covering 44 countries from 1995 to 2020, a system Generalized Method of Moments is adopted as the estimation technique of a dynamic panel model. Findings show that military outlays have a significant positive effect on education spending in sub-Saharan Africa. However, the sensitivity analysis reports a mitigated result, highlighting the diversity of evidence on the ‘guns better than butter’ literature. While military outlays positively affect education expenditures in central and southern African sub-regions, they crowd-out the public spending allocated to education development in Sahel & Lake Chad area, western and eastern sub-regions. These results, therefore, suggest that policy makers should promote the approach which considers defense as a component of socioeconomic development by regulating the perfect ratio of military spending that meets their needs.
The National Ignition Facility: Status and Plans for the Experimental Program

Abstract The National Ignition Facility (NIF), currently under construction at the University of California’s Lawrence Livermore National Laboratory, is a stadium-sized facility containing a 192-beam, 1.8-Megajoule, 500-Terawatt, 351-nm laser system and a 10-meter diameter target chamber with room for nearly 100 experimental diagnostics. NIF is being built by the National Nuclear Security Administration and when completed will be the world’s largest laser experimental system, providing a national center to study inertial confinement fusion and the physics of matter at extreme energy densities and pressures. NIF’s 192 energetic laser beams will compress fusion targets to conditions where they will ignite and burn, liberating more energy than required to initiate the fusion reactions. NIF experiments will allow the study of physical processes at temperatures approaching 100 million K and 100 billion times atmospheric pressure. These conditions exist naturally only in the interior of stars and in nuclear weapons explosions. In the course of designing the world’s most energetic laser system, a number of significant technology breakthroughs have been achieved. NIF is now entering the first phases of its laser commissioning program. Low-energy preamplifier rod laser shots have been successfully propagated through the entire laser chain. Higher energy shots are planned through the end of 2002. NIF’s target experimental systems are also being installed in preparation for laser performance and experimental capability commissioning starting in 2003.
Activation energy for electromigration in Cu films

Copper is a possible substitute for Al in very large scale integration interconnects because of its higher resistance to electromigration damage (EMD) and its lower electrical resistivity. In the present work, we report on electrical resistance measurements of the activation energy for EMD in Cu films as determined by an isothermal annealing method carried out under high vacuum conditions. Temperature measurement and control were accomplished by means of a Cu thin‐film thermistor. The activation energy for EMD of evaporated Cu films was found to be 0.79±0.02 eV.
Data-driven restoration of degraded binary MRF images using EM method

A data-driven restoration algorithm is developed for binary images degraded nonadditively with flip noises. The true image is assumed to be a realization of a Markov random field (MRF), and the nonadditive flip noises are assumed to be statistically independent and asymmetric. The parameter estimations of the noise and the true image are carried out iteratively in the context of an expectation and maximization (EM) procedure by approximating Baum's auxiliary function of the EM procedure. To approximate Baum's auxiliary function, the estimate of the true image at each EM iteration is used. Simulation examples show the effectiveness of the data-driven restoration algorithm and the parameter estimation procedures. <<ETX>>
Effects of measurement precision and finite numbers of electrodes on linear impedance imaging algorithms

Impedance imaging systems reconstruct approximations to the conductivity inside a body from electrical measurements made on the boundary. The linearized problem was studied by Calderon, who showed that if the conductivity differs little from a constant, then it can be reconstructed approximately. In his work, Calderon assumed that arbitrary current densities can be applied anywhere on the body’s surface and the resulting voltages perfectly measured. In practice, however, imaging systems apply currents through a finite number of electrodes on the surface and measure the resulting voltages with a limited precision.In this paper, linear algorithms are described for approximating the electrical conductivity in a disk from finitely many limited precision measurements. The effects of finite precision and electrode number on a two-dimensional version of Calderon’s method are studied. It is shown that as the measurement errors go to zero and the electrodes proliferate in a space-filling manner, the finite electro.