ShantanuT01/DACTYL-Pretraining huggingface dataset:
Existing datasets for training pedestrian detectors in images suffer from limited appearance and pose variation. The most challenging scenarios are rarely included because they are too difficult to capture due to safety reasons, or they are very unlikely to happen. The strict safety requirements in assisted and autonomous driving applications call for an extra high detection accuracy also in these rare situations. Having the ability to generate people images in arbitrary poses, with arbitrary appearances and embedded in different background scenes with varying illumination and weather conditions, is a crucial component for the development and testing of such applications. The contributions of this paper are three-fold. First, we describe an augmentation method for controlled synthesis of urban scenes containing people, thus producing rare or never-seen situations. This is achieved with a data generator (called DummyNet) with disentangled control of the pose, the appearance, and the target background scene. Second, the proposed generator relies on novel network architecture and associated loss that takes into account the segmentation of the foreground person and its composition into the background scene. Finally, we demonstrate that the data generated by our DummyNet improve performance of several existing person detectors across various datasets as well as in challenging situations, such as night-time conditions, where only a limited amount of training data is available. In the setup with only day-time data available, we improve the night-time detector by $17\%$ log-average miss rate over the detector trained with the day-time data only.
An irrational toric variety X is an analytic subset of the simplex associated to a finite configuration of real vectors. The positive torus acts on X by translation, and we consider limits of sequences of these translations. Our main result identifies all possible Hausdorff limits of translations of X as toric degenerations using elementary methods and the geometry of the secondary fan of the vector configuration. This generalizes work of Garcia-Puente et al., who used algebraic geometry and work of Kapranov, Sturmfels, and Zelevinsky, when the vectors were integral.
We turn back to some pioneering results concerning, in particular, nonlinear potential theory and non-homogeneous boundary value problems for the so called p-Laplacian operator. Unfortunately these results, obtained at the very beginning of the seventies, were kept in the shade. We believe that our proofs are still of interest, in particular due to their extreme simplicity. Moreover, some contributions seem to improve the results quoted in the current literature.
We undertake to develop a successful framework for commutative-associative hypercomplex numbers with the view to explicate and study associated geometric and generalized-relativistic concepts, basing on an interesting possibility to introduce appropriate multilinear metric forms in the treatment. The scalar polyproduct, which extends the ordinary scalar product used in bilinear (Euclidean and pseudo-Euclidean) theories, has been proposed and applied to be a generalized metric base for the approach. A fundamental concept of multilinear isometry is proposed. This renders possible to muse upon various relativistic physical applications based on anisotropic {\it versus} ordinary spatially-rotational case.
The solar photospheric abundance of oxygen is still a matter of debate. For about ten years some determinations have favoured a low oxygen abundance which is at variance with the value inferred by helioseismology. Among the oxygen abundance indicators, the forbidden line at 630nm has often been considered the most reliable even though it is blended with a NiI line. In Papers I and Paper II of this series we reported a discrepancy in the oxygen abundance derived from the 630nm and the subordinate [OI] line at 636nm in dwarf stars, including the Sun. Here we analyse several, in part new, solar observations of the the centre-to-limb variation of the spectral region including the blend at 630nm in order to separate the individual contributions of oxygen and nickel. We analyse intensity spectra observed at different limb angles in comparison with line formation computations performed on a CO5BOLD 3D hydrodynamical simulation of the solar atmosphere. The oxygen abundances obtained from the forbidden line at different limb angles are inconsistent if the commonly adopted nickel abundance of 6.25 is assumed in our local thermodynamic equilibrium computations. With a slightly lower nickel abundance, A(Ni)~6.1, we obtain consistent fits indicating an oxygen abundance of A(O)=8.73+/-0.05. At this value the discrepancy with the subordinate oxygen line remains. The derived value of the oxygen abundance supports the notion of a rather low oxygen abundance in the solar hotosphere. However, it is disconcerting that the forbidden oxygen lines at 630 and 636nm give noticeably different results, and that the nickel abundance derived here from the 630nm blend is lower than expected from other nickel lines.
It is reviewed how Compton scattering sum rules relate low-energy nucleon structure quantities to the nucleon excitation spectrum. In particular, the GDH sum rule and recently proposed extensions of it will be discussed. These extensions are sometimes more calculationally robust, which may be an advantage when estimating the chiral extrapolations of lattice QCD results, such as for anomalous magnetic moments. Subsequently, new developments in our description of the nucleon excitation spectrum will be discussed, in particular a recently developed chiral effective field theory framework for the $\Delta(1232)$-resonance region. Within this framework, we discuss results on $N$ and $\Delta$ masses, the $\gamma N \Delta$ transition and the $\Delta$ magnetic dipole moment.
A large spin-accumulation voltage of more than 1.5 mV at 1 mA, i.e., a magnetoresistance of 1.5 {\Omega}, was measured by means of the local three-terminal magnetoresistance in nondegenerate Si-based lateral spin valves (LSVs) at room temperature. This is the largest spin-accumulation voltage measured in semiconductor-based LSVs. The modified spin drift-diffusion model, which successfully accounts for the spin drift effect, explains the large spin-accumulation voltage and significant bias-current-polarity dependence. The model also shows that the spin drift effect enhances the spin-dependent magnetoresistance in the electric two terminal scheme. This finding provides a useful guiding principle for spin metal-oxide semiconductor field-effect transistor (MOSFET) operations.
We show that a recent proposal by Nambu to generate a hierarchy among Yukawa couplings in the standard model may be easily implemented in superstring models. In such models, two of the main ingredients of the Nambu proposal find a natural explanation: minimising with respect to the Yukawas amounts to a minimisation with respect to the underlying moduli fields and a constraint on the Yukawas of the type of the Veltman condition may be attributed to the relaxation process to a phenomenologically viable string vacuum.
In this paper, we prove the scattering for radial solutions to energy-critical nonlinear Schr\"odinger equations with regular potentials in defocusing case.
We present a new isocurvature mode present in scalar-tensor theories of gravity that corresponds to a regular growing solution in which the energy of the relativistic degrees of freedom and the scalar field that regulates the gravitational strength compensate during the radiation dominated epoch on scales much larger than the Hubble radius. We study this isocurvature mode and its impact on anisotropies of the cosmic microwave background for the simplest scalar-tensor theory, i.e. the extended Jordan-Brans-Dicke gravity, in which the scalar field also drives the acceleration of the Universe. We use Planck data to constrain the amplitude of this isocurvature mode in the case of fixed correlation with the adiabatic mode and we show how this mode could be generated in a simple two field inflation model.
Context. The CoRoT and Kepler missions have paved the way for synergies between exoplanetology and asteroseismology. The use of seismic data helps providing stringent constraints on the stellar properties which directly impact the results of planetary studies. Amongst the most interesting planetary systems discovered by Kepler, Kepler-444 is unique by the quality of its seismic and classical stellar constraints. Its magnitude, age and the presence of 5 small-sized planets orbiting this target makes it an exceptional testbed for exoplanetology. Aims. We aim at providing a detailed characterization of Kepler-444, focusing on the dependency of the results on variations of key ingredients of the theoretical stellar models. This thorough study will serve as a basis for future investigations of the planetary evolution of the system orbiting Kepler-444. Methods. We use local and global minimization techniques to study the internal structure of the exoplanet-host star Kepler-444. We combine seismic observations from the Kepler mission, Gaia DR2 data and revised spectroscopic parameters to precisely constrain its internal structure and evolution. Results. We provide updated robust and precise determinations of the fundamental parameters of Kepler-444 and demonstrate that this low-mass star bore a convective core during a significant portion of its life on the main-sequence. Using seismic data, we are able to estimate the lifetime of the convective core to approximately 8 Gyr out of the 11 Gyr of the evolution of Kepler-444. The revised stellar parameters found by our thorough study are M = 0.754 +- 0.03M_Sun , R = 0.753 +- 0.01R_Sun , Age = 11 +- 1 Gy.
The supersymmetric generalization of dilatations in the presence of the dilaton is defined. This is done by defining the supersymmetric dilaton geometry which is motivated by the supersymmetric volume preserving diffeomorphisms. The resulting model is classical superconformal field theory with an additional dilaton-axion supermultiplet coupled to the supersymmetric gauge theory, where the dilaton-axion couplings are nonrenormalizable. The possibility of spontaneous scale symmetry breaking is investigated in this context. There are three different types of vacua with broken scale symmetry depending on the details of the dilaton sector: unbroken supersymmetry, spontaneously broken supersymmetry and softly broken supersymmetry. If the scale symmetry is broken in the bosonic vacuum, then the Poincar\'e supersymmetry must be broken at the same time. If the scale symmetry is broken in the fermionic vacuum but the bosonic vacuum remains invariant, then the Poincar\'e supersymmetry can be preserved as long as the R-symmetry breaking is specifically related to the scale symmetry breaking.
The parameters and elemental abundances of atmospheres for ten thick-disk red giants was determined from high-resolution spectra by the method of model stellar atmospheres. The results of a comparative analysis of the [Na/Fe] abundances in the atmospheres of the investigated stars and thin disk red giants are presented. Sodium in the atmospheres of thick-disk red giants is shown to have no overabundances typical of thin-disk red giants.
We present phase-resolved spectroscopy and extensive survey photometry of the detached eclipsing binary system XY Cet, which is composed of two metallic-lined stars. We measure their masses to be 1.773 +/- 0.016 and 1.615 +/- 0.014 Msun and their radii to be 1.873 +/- 0.035 and 1.773 +/- 0.029 Rsun, resulting in logarithmic surface gravities of 4.142 +/- 0.016 and 4.149 +/- 0.014 (cgs). We determine effective temperatures of 7870 +/- 115 and 7620 +/- 125 K. The projected rotational velocities are 34.4 +/- 0.4 and 34.1 +/- 0.4 km/s, which are close to synchronous. Theoretical models cannot match all of these properties, but come closest for a solar helium and metal abundance and an age in the region of 850 Myr. We obtain the individual spectra of the two stars by the spectral disentangling method, and compare them to synthetic spectra calculated for the measured effective temperatures and a solar chemical composition. Both stars show enhanced abundances of iron-group elements and clear deficiencies of Ca I and Sc II, confirming their classification as Am stars. We also find strong overabundances of Zr II and the rare-earth species La II, Ce II and Nd II, a hallmark of chemically peculiar A-stars. XY Cet is a prime candidate for detailed spectroscopic analyses of metallic-lined stars whose masses and radii are known to accuracies of 1-2%.
There are many proposed prediction methods for solar cycles behavior. In a previous paper we updated the full-shape curve prediction of the current solar cycle 24 using a non-linear dynamics method and we compared the results with the predictions collected by the NOAA/SEC prediction panel, using observed data up to October 2010. The aim of the present paper is to give a quantitative evaluation, a posteriori, of the performances of these prediction methods using a specific global error, updated on a monthly basis, which is a measure of the global performance on the predicted shape (both amplitude and phase) of the solar cycle. We suggest also the use of a percent cycle similarity degree, to better evaluate the predicted shape of the solar cycle curve.
We report the growth of high-quality triangular GaN nanomesas, 30-nm thick, on the C-face of 4H-SiC using nano selective area growth (NSAG) with patterned epitaxial graphene grown on SiC as an embedded mask. NSAG alleviates the problems of defective crystals in the heteroepitaxial growth of nitrides, and the high mobility graphene film can readily provide the back low-dissipative electrode in GaN-based optoelectronic devices. The process consists in first growing a 5-8 graphene layers film on the C-face of 4H- SiC by confinement-controlled sublimation of silicon carbide. The graphene film is then patterned and arrays of 75-nanometer-wide openings are etched in graphene revealing the SiC substrate. 30-nanometer-thick GaN is subsequently grown by metal organic vapor phase epitaxy. GaN nanomesas grow epitaxially with perfect selectivity on SiC, in openings patterned through graphene, with no nucleation on graphene. The up-or-down orientation of the mesas on SiC, their triangular faceting, and cross-sectional scanning transmission electron microscopy show that they are biphasic. The core is a zinc blende monocrystal surrounded with single-crystal hexagonal wurtzite. The GaN crystalline nanomesas have no threading dislocations, and do not show any V-pit. This NSAG process potentially leads to integration of high-quality III-nitrides on the wafer scalable epitaxial graphene / silicon carbide platform.
Aiming to clarify the mechanisms governing the interlayer magnetic coupling, we have investigated the stacking energy and interlayer magnetism of bilayer CrBr$_3$ systemically. The magnetic ground states of bilayer CrBr$_3$ with different R-type and H-type stacking orders are established, which is found to be in good agreement with recent experiment (Science $\mathbf{366}$,983(2019)).Further analyses indicate that the stacking energy is mainly determined by the Coulomb interaction between the interlayer nearest-neighbor Br-Br atoms. While interlayer magnetism can be understood by a competition between super-super-exchange interactions involving $t_{2g}$-$t_{2g}$ and $t_{2g}$-$e_g$ orbitals and semi-covalent exchange interactions of $e_g$-$e_g$ orbitals. Our studies give an insightful understanding for stacking order and interlayer magnetism of bilayer CrBr$_3$, which should be useful to understand quantum confinement effect of other layered magnets in two-dimensional limit.
Relativistic quantum effects on physical observables of scalar charged particles are studied. Possible peculiarities of their behavior that can be verified in an experiment can confirm several fundamental conceptions of quantum mechanics. For observables independent of charge variable, we propose relativistic Wigner function formalism that contains explicitly the measurement device frame. This approach can provide the description of charged particles gas (plasma). It differs from the traditional one but is consistent with the Copenhagen interpretation of quantum mechanics. The effects that are connected with this approach can be observed in astrophysical objects - neutron stars.
Simultaneous differential thermal analysis (DTA) and thermogravimetric (TG) measurements with copper oxide/aluminum oxide mixtures were performed in atmospheres with varying oxygen partial pressures and with crucibles made of different materials. Only sapphire and platinum crucibles proved to be stable under conditions that are useful for the growth of CuAlO$_2$ delafossite single crystals. Then the ternary phase diagram Al$_2$O$_3$-CuO-Cu and its isopleth section Cu$_2$O-Al$_2$O$_3$ were redetermined. Millimeter sized crystals could be obtained from copper oxide melts with 1-2 mol % addition of aluminum oxide that are stable in platinum crucibles held in oxidizing atmosphere containing 15-21 % oxygen.
Molecular functionalization of nanoparticles and metallic substrates can be used to tune their properties for specific applications. However, polycrystalline substrates and nanoparticles exhibit surface planes with distinct crystallographic orientations. Therefore, the development of reliable strategies for molecular functionalization requires knowledge of the role of the surface plane orientation in the growth kinetics, structure, and properties of the molecular layer. Here, we apply a multiscale analysis to investigate the self-assembly of 4,4'-biphenyl-dicarboxylic acid (BDA) on Ag(111) and critically discuss the difference to Ag(100). Whereas the structural motifs for intact and fully deprotonated BDA are similar on both surfaces, the intermediate phases comprising partially deprotonated BDA differ in the structure and chemical composition. A real-time view of the phase transformations enables us to present a generalized picture of the phase transformations between the self-assembled molecular phases on the surfaces and underline important features such as the phase stabilization of the chemical composition and the mechanism of the related burst transformation. The influence of the substrate orientation on the structure of molecular layers and phase transformations provides the necessary background for developing functionalization strategies of the substrates displaying multiple surface planes and kinetic models for the growth near thermodynamic equilibrium.
The purpose of this paper is twofold. First, we derive theoretically, using appropriate transformation on $x_n$, the closed-form solution of the nonlinear difference equation \[ x_{n+1} = \frac{1}{\pm 1 + x_n},\qquad n\in \mathbb{N}_0. \] We mention that the solution form of this equation was already obtained by Tollu et al. in 2013, but through induction principle, and one of our purpose is to clearly explain how was the formula appeared in such structure. After that, with the solution form of the above equation at hand, we prove a case of Sroysang's conjecture (2013); i.e., given a fixed positive integer $k$, we verify the validity of the following claim: \[ \lim_{x \rightarrow \infty}\left\{ \frac{f(x+k)}{f(x)}\right\}= \phi, \] where $\phi=(1+\sqrt{5})/2$ denotes the well-known golden ratio and the real valued function $f$ on $\mathbb{R}$ satisfies the functional equation $f(x+2k)=f(x+k) + f(x)$ for every $x\in \mathbb{R}$. We complete the proof of the conjecture by giving out an entirely different approach for the other case.
We study the relation between the acquisition and analysis of data and quantum theory using a probabilistic and deterministic model for photon polarizers. We introduce criteria for efficient processing of data and then use these criteria to demonstrate that efficient processing of the data contained in single events is equivalent to the observation that Malus' law holds. A strictly deterministic process that also yields Malus' law is analyzed in detail. We present a performance analysis of the probabilistic and deterministic model of the photon polarizer. The latter is an adaptive dynamical system that has primitive learning capabilities. This additional feature has recently been shown to be sufficient to perform event-by-event simulations of interference phenomena, without using concepts of wave mechanics. We illustrate this by presenting results for a system of two chained Mach-Zehnder interferometers, suggesting that systems that perform efficient data processing and have learning capability are able to exhibit behavior that is usually attributed to quantum systems only.
In accretion-based models for Sgr A* the X-ray, infrared, and millimeter emission arise in a hot, geometrically thick accretion flow close to the black hole. The spectrum and size of the source depend on the black hole mass accretion rate $\dot{M}$. Since Gillessen et al. have recently discovered a cloud moving toward Sgr A* that will arrive in summer 2013, $\dot{M}$ may increase from its present value $\dot{M}_0$. We therefore reconsider the "best-bet" accretion model of Moscibrodzka et al., which is based on a general relativistic MHD flow model and fully relativistic radiative transfer, for a range of $\dot{M}$. We find that for modest increases in $\dot{M}$ the characteristic ring of emission due to the photon orbit becomes brighter, more extended, and easier to detect by the planned Event Horizon Telescope submm VLBI experiment. If $\dot{M} \gtrsim 8 \dot{M}_0$ this "silhouette of the black hole will be hidden beneath the synchrotron photosphere at 230 GHz, and for $\dot{M} \gtrsim 16 \dot{M}_0$ the silhouette is hidden at 345 GHz. We also find that for $\dot{M} > 2 \dot{M}_0$ the near-horizon accretion flow becomes a persistent X-ray and mid-infrared source, and in the near-infrared Sgr A* will acquire a persistent component that is brighter than currently observed flares.
We prove that the extension of the double ramification cycle defined by the first-named author (using modifications of the stack of stable curves) coincides with that defined by the last-two named authors (using an extended Brill-Noether locus on suitable compactified universal Jacobians). In particular, in the untwisted case we deduce that both of these extensions coincide with that constructed by Li and Graber-Vakil using a virtual fundamental class on a space of rubber maps.
Bolometers are a powerful and vital means of detecting light in the IR to THz frequencies, and they have been adopted for a range of uses from astronomical observation to thermal imaging. As uses diversify, there is an increasing demand for faster, more sensitive room-temperature bolometers. To this end, graphene has generated interest because of its miniscule heat capacity and its intrinsic ultra-broadband absorption, properties that would allow it to quickly detect low levels of light of nearly any wavelength. Yet, graphene has disappointed its expectations in traditional electrical bolometry at room temperature, because of its weakly temperature-dependent resistivity and exceptionally high thermal conductivity. Here, we overcome these challenges with a new approach that detects light by tracking the resonance frequency of a graphene nanomechanical resonator. The absorbed light heats up and thermally tensions the resonator, thereby changing its frequency. Using this approach, we achieve a room-temperature noise-equivalent power of 7 pW/Hz^1/2, a value 100 times more sensitive than electrical graphene bolometers, and speeds (1.3 MHz) that greatly surpass state-of-the-art microbolometers.