Miracle-dz/UniFAR-FTUs huggingface dataset:
Near-Field 3D Sparse SAR Direct Imaging with Irregular Samples

Sparse imaging is widely used in synthetic aperture radar (SAR) imaging. Compared with the traditional matched filtering (MF) methods, sparse SAR imaging can directly image the scattered points of a target and effectively reduce the sidelobes and clutter in irregular samples. However, in view of the large-scale computational complexity of sparse reconstruction with raw echo data, traditional sparse reconstruction algorithms often require huge computational expense. To solve the above problems, in this paper, we propose a 3D near-field sparse SAR direct imaging algorithm for irregular trajectories, adopting a piece of preliminary information in the SAR image to update the dictionary matrix dimension, using the Gaussian iterative method, and optimizing the signal-processing techniques, which can achieve 3D sparse reconstruction in a more direct and rapid manner. The proposed algorithm was validated through simulations and empirical study of irregular scanning scenarios and compared with traditional MF and sparse reconstruction methods, and was shown to significantly reduce the computation time and effectively preserve the complex information of the scenes to achieve high-resolution image reconstruction.
The discovery of an X-ray selected, radio-loud quasar at z = 3.9

About 600 weak X-ray sources from a data base of about 100,000 2-4sigma fluctuations derived from Einstein Observatory imaging proportional counter X-ray images are selected on the basis of a flux-limited catalog of radio sources in the northern sky. Optical spectroscopy of only six of these sources resulted in the discovery of a quasar with an emission-line redshift of 3.87. Subsequent VLA observations reveal the source to have a flat-spectrum radio core plus an unresolved radio lobe 2.5 arcsec away with a spectral index of 1.45. The lobe is connected to the core by a weak jet. The integrated flux density of the source at 20 cm is 0.66 Jy. The v magnitude of the quasar is 19.5, and the tentative X-ray sources has a very soft spectrum. The properties of this object are discussed in the context of known high-redshift radio sources and existing X-ray selected quasar samples, and the potential of the present discovery technique for examining the properties of very distant active galaxies is explored. 20 refs.
Tale of the Titers: Serologic Testing for SARS-CoV-2—Yes, No, and Maybe, With Clinical Examples From the IDSA Diagnostics Committee

Abstract Diagnosis of acute severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection relies on detection of viral antigens or amplified viral nucleic acids. Serology, although invaluable for epidemiology, is not routinely needed clinically. However, in some settings, serologic data may have direct clinical utility: for example, in evaluation of persistent symptoms in patients without a prior diagnosis of acute infection. In contrast, SARS-CoV-2 serologic testing is sometimes used or requested in situations in which existing data do not support it, such as determination of need for vaccination. In this study, we describe available methods of serologic testing and provide cases supported by clinical vignettes of where such tests can be helpful, as well as examples where they are not. These examples may help clarify clinical decision making in this rapidly evolving area.
IP Framework Study

The transition of Culture and the Creative Industries towards a more distributed, asynchronous, agile, geographically-independent, rapid creation model enabled by digital technologies, has accelerated exponentially during the Covid pandemic. The transformation of the sector had been gaining momentum before the current crisis and had been progressively speeding up ever since the advent of Napster on the 1st of June 1999ii, when the hacking subculture was the first to exploit affordances of Peer-to-Peer digital asset sharing to establish communities at a grand scale, and simultaneously precipitated the music sector into an overnight digital transitioniii. Since then models implemented by the CCI in response to early challenges, which utilised emerging technological affordances, have become a universal template for digital transformations across other industries. The CCI approach to knowledge acquisition and methodologies for experimentation have proven to be the key ingredient of the processes required to manage complexities emerging from frontier technologies. With increased demand for collaboration to solve grand societal challenges highlighted by the recent crisis, a new anchoring of the CCI as central facilitator of the data-driven cross-domain economy is emerging with a horizontal function that bridges all domains. Within this paper we list the priorities for the repositioning of the CCI at the centre of cross-domain industry innovation. A testbed for digital transition The advent of Napster forced the music industry to migrate overnight from tangible product to the digital format, adopt the cloud as a warehouse, turn to the data spreadsheet as the album crate, and use music metadata to replace attractive album covers as means of identification. The entire sector
Radar Attenuation in the Shallow Martian Subsurface: RIMFAX Time‐Frequency Analysis and Constant‐Q Characterization Over Jezero Crater Floor

Attenuation of radar waves in the subsurface can be quantified with a constant‐Q approximation through time‐frequency analysis. We implement the centroid frequency‐shift method and study Radar Imager for Mars' Subsurface Exploration (RIMFAX) data acquired along the Mars 2020 Perseverance rover traverse. Attenuation is among key media properties, but quantified estimates need to account for instrument characteristics and limitations in the analysis technique. We ensure accurate constant‐Q characterization and present the first estimates of radar attenuation in the upper 5 m of the shallow Martian subsurface. Over Jezero Crater Floor, constant‐Q is on average 70.4 ± 7.7, which equals an attenuation of −2.6 ± 0.3 dB/m at RIMFAX’ 675 MHz center frequency. Regions comprising the Máaz or Séítah formations have similar attenuation properties that are consistent with magmatic lithologies.
Numerical Simulation of Incompressible Flow Problems Using an Unstructured Staggered Mesh Method

A number of two dimensional staggered unstructured discretisation schemes for the solution of fluid flow and heat transfer problems have been developed. All schemes store and solve velocity vector components at cell faces with scalar variables solved at cell centres. The velocity is resolved into face-normal and face-parallel components and the various schemes investigated differ in the treatment of the parallel component. Steady-state and time-dependent fluid flow and thermal energy equations are solved with the well known pressure correction scheme, SIMPLE, employed to couple continuity and momentum. The numerical methods developed are tested on well known benchmark cases: the Lid-Driven Cavity, Natural Convection in a Cavity and Melting of Gallium in a rectangular domain. The results obtained are shown to be comparable to benchmark, but with accuracy dependent on scheme selection.
Action Sensing Based on Computed Volume

The local features based on interest point have achieved much success in action sensing recently. The interest point is not only limited to 2D space, but also extended to 3D space. We apply the 3D interest point to action sensing. A classic method to use 3D interest point is through creating a feature using histogram vector based on bag of words; some better methods take advantage of the position of each interest point besides the local feature; however, it’s difficult to position these points due to the complexity of an action. We propose a simple method to position each interest point, and create a new feature for action sensing. Evaluation of the approach on two sets of videos suggests its effectiveness.
High power single-lateral-mode operation of InAs quantum dot based ridge type laser diodes by utilizing a double bend waveguide structure

We report on the high-power, single-lateral-mode operation of InAs quantum dot (QD) based ridge type laser diodes (LDs) by utilizing a double bend (DB) waveguide structure. The LDs were designed so that only fundamental modes propagate and higher optical modes are suppressed through the bent regions. DB waveguide LDs allow the use of wide ridge widths for fundamental mode operations, which helps to increase their output power via the increase in their net gain. We measured continuous wave single-lateral-mode output power of up to 310 mW from InAs QD DB waveguide LDs manufactured with 10-μm-wide stripes without facet coating.
Security solution against denial of service attacks in BESIP system

This article deals about embedded SIP communication server with an easy integration into the computer network based on open source solutions and its effective defense against the most frequent attack in the present - Denial of Service. The article contains brief introduction into the Bright Embedded Solution for IP Telephony – BESIP and describes the most common types of DoS attacks, which are applied on SIP elements of the VoIP infrastructure including the results of defensive mechanism that has been designed.
Consistent inverse probability of treatment weighted estimation of the average treatment effect with mismeasured time‐dependent confounders

In longitudinal studies, the inverse probability of treatment weighted (IPTW) method is commonly employed to estimate the effect of time‐dependent treatments on an outcome of interest. However, it has been documented that when the confounders are subject to measurement error, the naive IPTW method which simply ignores measurement error leads to biased treatment effect estimation. In the existing literature, there is a lack of measurement error correction methods that fully remove measurement error effect and produce consistent treatment effect estimation. In this article, we develop a novel consistent IPTW estimation procedure for longitudinal studies. The key step of the proposed method is to use the observed data to construct a corrected function that is unbiased of the unknown IPTW function. Simulation studies reveal that the proposed method outperforms the existing consistent and approximate measurement error correction methods for IPTW estimation of the average treatment effect. Finally, we apply the proposed method to analyze a real dataset.
Effects of different maturity status on change of direction performance of youth tennis players

The aim of this study was to examine the maturational status (i.e., peak height velocity [PHV]) differences in neuromuscular performance (i.e., vertical jump, linear sprint, change of direction (COD) using different tests, and change of direction deficit [CODD]) of young tennis players. One hundred and two tennis players (70 boys and 52 girls; age 13.9 ± 2.0 years, body mass 53.3 ± 12.7 kg, height 163.1 ± 11.9 cm) participated in the study and were divided into Pre-PHV (n = 26), Circa-PHV (n = 33) and Post-PHV (n = 43) groups. Testing included speed (5, 10, and 20 m), COD tests (i.e., modified 5-0-5, pro-agility and hexagon), and bilateral/unilateral countermovement jump (CMJ). Pre- and Circa-PHV players presented lower levels of performance in jumping ability (i.e., both bilateral and unilateral CMJs; P < 0.001; ES: 0.85 to 0.98), linear sprints (5 to 20 m; P < 0.05 to < 0.001; ES: 0.67 to 1.19) and COD ability tests (modified 5-0-5 test, pro-agility and hexagon) compared to the Post-PHV players. Moreover, Pre-PHV players presented lower CODD% (p < 0.05; ES: 0.68–0.72) than Post-PHV for both forehand and backhand sides, and Circa-PHV showed lower values in the CODD of the rolling situation to the forehand side (p < 0.05; ES: 0.58). Among the COD tests, the pro-agility test seems to be a simple, easy-to-implement and reliable test, which can provide interesting information about the COD with higher entry speeds. Moreover, specific training strategies related to the PHV and focused not only on the neuromuscular training and COD workouts, but also on maximizing motor skill proficiency, should be recommended.
Elastography methods applicable to the eye

Elastography is the mapping of tissues and cells by their respective mechanical properties, such as elasticity and viscosity. Our interest primarily lies in the human eye. Combining Scanning Laser Doppler Vibrometry (SLDV) with geometrically focused mechanical vibratory excitations of the cornea, it is possible to reconstruct these mechanical properties of the cornea. Experiments were conducted on phantom corneas as well as excised donor human corneas to test feasibility and derive a method of modeling. Finite element analysis was used to recreate the phantom studies and corroborate with the experimental data. Results are in close agreement. To further expand the study, lamb eyes were used in MR Elastography studies. 3D wave reconstruction was created and elastography maps were obtained. With MR Elastography, it would be possible to noninvasively measure mechanical properties of anatomical features not visible to SLDV, such as the lens and retina. Future plans include creating a more robust finite element model, improving the SLDV method for in-vivo application, and continuing experiments with MR Elastography.
CHARACTERISTICS OF TWO-PHASE FLOW AND EVAPORATION HEAT TRANSFER IN A CAPILLARY AT CONSTANT HEAT FLUXES

Physical and mathematical models of a capillary tube at constant heat flux are established. The two-phase flow mechanism consists of the core vapor flow and the liquid film flow, which are driven by the gradients of capillary pressure and disjoining pressure. There also exists a vapor-liquid interaction of shear stress at the interface, which is due to both the velocity difference between the vapor and the liquid, and the momentum transfer of evaporation. The heat transfer mechanism is composed of liquid film conduction and evaporation at the vapor-liquid interface. In the models presented, the evaporating interfacial region is not divided into several subregions; the thickness of the liquid film is solved by the governing differential equations. The effects of the applied heat flux and the radius of the capillary on the liquid film profile are calculated and compared. With the increase of heat flux and capillary radius, the length of the evaporating interfacial region decreases, and the former factor has more significant influence on both the meniscus position in the capillary tube and the thickness of the liquid film.
Sensitivity analysis of write field with respect to design parameters for perpendicular recording heads

In this article, an analytical solution for the write field distribution in perpendicular recording system is presented. The field distribution in soft underlayer has been taken into consideration. The computed results agree well with numerical simulations. To investigate the influence of the leading design parameters on the write field characteristics, the sensitivity analysis based on response surface methodology is carried out. Besides, the effect of the soft underlayer on the write field is also studied to provide guidelines for the perpendicular recording head design.
Antarctic sea ice holds the fate of Antarctic ice-shelf basal melting in a warming climate

Changes in the Antarctic ice sheet play a critical role in the Southern Ocean and global climates. Although many studies have pointed out that enhanced ocean heat delivery onto the Antarctic continental shelf regions can cause significant changes in Antarctic ice-shelf basal melting, the associated physical mechanisms require further research. Here, we perform numerical experiments using an ocean-sea ice model with an ice-shelf component to simulate future projections in Antarctic ice-shelf basal melting in a warming climate, focusing on the driving mechanism and the physical linkages with the seasonal Antarctic sea-ice fields and coastal water masses. The model projects a distinct superlinear response of ice-shelf basal melting to future atmospheric warming, demonstrating that future projections of the Antarctic and Southern Ocean climate bifurcate with the level of global warming. Detailed examinations of sea ice and water masses show that in an extreme warming scenario, a combination of enhanced intrusions of warm deep water and warm summertime surface water can cause the nonlinear response of Antarctic ice-shelf basal melting. A large reduction in Antarctic coastal sea ice and the associated ocean freshening by decreasing coastal sea-ice production in winter provide favorable conditions for summertime warm surface water formation and warm deep water intrusions onto some continental shelves. The model results demonstrate that disappearing summertime sea ice along the Antarctic coastal margins in a warming climate heralds the nonlinear increase in Antarctic ice-shelf basal melting, presumably contributing to the negative mass balance of the Antarctic ice sheet and the sea-level rise.
Nematic topological line defects as optical waveguides

Liquid crystals are starting to attract attention for applications beyond the display technology. Their high birefringence, softness, and possibility to form complex topological defect structures allow for easy light manipulation in systems ranging from cholesteric lasers to droplet resonators and wave guides. Recent interest in light-induced topological defects and light propagation along the defects stimulated us to develop a customized version of the Finite-Difference Time-Domain (FDTD) method for solving Maxwell's equations on a discrete time and space lattice. Here, we present an overview of our recent simulations, modeling the time-evolution of electromagnetic fields along birefringent structures in nematic liquid crystals, specifically light propagation along nematic defect lines. In the regime of high light intensity beams the modelling approach includes also a light induced modification of local nematic ordering obtained via a qtensor free energy minimization procedure. We show how topological invariants of the nematic and polarization fields combine and also affect the beam intensity profile. Finally, off-axis propagation of beams with respect to the defect lines is considered.
General framework about defect creation at the Si∕SiO2 interface

This paper presents a theoretical framework about interface state creation rate from Si–H bonds at the Si∕SiO2 interface. It includes three main ways of bond breaking. In the first case, the bond can be broken, thanks to the bond ground state rising with an electrical field. In two other cases, incident carriers will play the main role either if there are very energetic or very numerous but less energetic. This concept allows one to physically model the reliability of metal oxide semiconductor field effect transistors, and particularly negative bias temperature instability permanent part, and channel hot carrier to cold carrier damage.
Interaction Control of a Robotic Manipulator With the Surface of Deformable Object

Robotic manipulation of deformable objects has drawn the attention of researchers over the past few years and is associated with a large spectrum of new application perspectives. In this article, we present an efficient integrated motion planning framework to effectively and accurately control a robotic manipulator executing interactive tasks on the surface of a deformable object. The proposed interactive motion planning framework is based on a mesh representation of the object, integrating three efficient preprocessing algorithmic steps, including visual object segmentation, finite element method deformation tracking, and local mesh parameterization. The use of barycentric coordinates, defined on the mesh triangles, enables the establishment of bijective transformations between the deformable part of an object surface and its planar (static and dynamic) parameterized mapping. By merging these spatial transformations with the preprocessing steps, in combination with an active stiffness scheme for robot manipulator control, we are able to achieve accurate and reactive motion planning of interactive trajectories, even under large and persistent visual occlusions (such as due to the presence of the robot in the visual scene). An extensive experimental evaluation study is presented, involving a robotic manipulator in interaction with a hemispherical model of controllable periodic active deformation, which permits precise ground truth derivation. Motion planning accuracy is evaluated in comparison with our previous direct vision-based approach, showing clearly superior performance of the proposed approach under all experimental conditions. The performance of the proposed framework is also further highlighted in tasks involving physical point tracking, interactive programming by human demonstration, as well as contact force regulation.
On the massive star origin of 26Al in the Cygnus region

The COMPTEL map of the 1.809 MeV line, which is attributed to the radioactive decay of 26Al, shows significant excess emission in the Cygnus region. We investigate counterparts of this emission, based on COMPTEL data accumulated over 8 years. Previous studies suggested that this flux is due to the integrated, but unresolved, nucleosynthesis from young, massive objects like Wolf Rayet (WR) stars and core collapse supernovae. Beside a static scenario of known point sources-WR stars and SNRs-we consider OB associations in a dynamic scenario to model the observed flux in the Cygnus region. We carry out population synthesis studies to determine the time-dependent production of 26Al and also kinetic as well as radiative energy. Furthermore we consider the impact of enhanced 26Al yields probably occurring in a fraction of massive close binary systems. We compare the nucleosynthesis results of our OB association model with recent measurements in the Cygnus region.
Evaluation of Fly Ash from Co-Combustion of Paper Mill Wastes and Coal as Supplementary Cementitious Materials

The applications of waste-derived fuel from paper mills in industrial boilers benefit the reduction of carbon emissions. However, the co-combustion of waste-derived fuel and coal causes significant changes in the characteristics of the ash and brings about the need to find possible means of the utilization of the ash produced. In this work fly, ash samples were collected from circulating fluidized bed (CFB) boilers co-combusting paper mill wastes with coal and analyzed in detail. The chemical, physical, and thermal characteristics of two different co-combustion fly ashes (CCFA) were investigated using X-ray fluorescence (XRF), X-ray diffraction (XRD), thermogravimetry (TG), and scanning electron microscope (SEM). The chemical composition of CCFA is largely affected by the fuel source type. Thermal analyses of CCFA show that the type of desulfurization system used by the boiler influences the form of sulfate present in the fly ash. The presence of calcium sulfite hemihydrate can cause a high loss in the ignition of CCFA. By comparing the physical requirements specified in the ASTM standard for coal fly ash to be used in concrete, the CCFA produced from paper mill wastes was found to show good potential as supplementary cementitious materials.