799 research outputs found

    Dynamic Adaptation on Non-Stationary Visual Domains

    Full text link
    Domain adaptation aims to learn models on a supervised source domain that perform well on an unsupervised target. Prior work has examined domain adaptation in the context of stationary domain shifts, i.e. static data sets. However, with large-scale or dynamic data sources, data from a defined domain is not usually available all at once. For instance, in a streaming data scenario, dataset statistics effectively become a function of time. We introduce a framework for adaptation over non-stationary distribution shifts applicable to large-scale and streaming data scenarios. The model is adapted sequentially over incoming unsupervised streaming data batches. This enables improvements over several batches without the need for any additionally annotated data. To demonstrate the effectiveness of our proposed framework, we modify associative domain adaptation to work well on source and target data batches with unequal class distributions. We apply our method to several adaptation benchmark datasets for classification and show improved classifier accuracy not only for the currently adapted batch, but also when applied on future stream batches. Furthermore, we show the applicability of our associative learning modifications to semantic segmentation, where we achieve competitive results

    On the Nature of the Apparent Ring Galaxy SDSS J075234.33+292049.8

    Full text link
    (abridged) An object classified as a galaxy in on-line data bases and revealed on sky survey images as a distant ring galaxy is a rare case of polar ring galaxy where the ring is only slightly inclined to the equatorial plane of the central body. SDSS imaging indicates that the diameter of the ring is about 36 kpc. The SDSS data was combined with long-slit spectroscopic observations and with Fabry-Perot Interferometer H-beta mapping obtained at the Russian Academy of Sciences 6-m telescope. We derived the complex morphologies of this presumed ring galaxy from a combination of SDSS images and from the kinematical behaviour of the central body and of the ring, and determined the stellar population compositions of the two components from SDSS colours, spectroscopy, and evolutionary stellar synthesis models. The ring metallicity is slightly under-abundant. The total luminosity and the total mass of the system are not extreme, but the rather high M/L~20 indicates the presence of large amounts of dark matter. Two alternative explanations of this object are proposed (1) a ring formed by two semi-circular and tight spiral arms at the end of a central bar with a warp or precession of the ring material. The object could, therefore, be explained as an extreme SBa(R) galaxy, or (2) a Polar Ring Galaxy where the inner object is an S0 and the ring is significantly more luminous than the central object. The compound object would then be similar to the NGC 4650A galaxy, being a rare object with a polar component only modestly inclined to the equatorial plane of the central body. Arguments for (and against) both explanations are given and discussed, with the second alternative being more acceptable.Comment: 16 pages, 11 figures, MNRAS in pres

    Very metal-poor galaxies: ionized gas kinematics in nine objects

    Full text link
    The study of ionized gas morphology and kinematics in nine eXtremely Metal-Deficient (XMD) galaxies with the scanning Fabry-Perot interferometer on the SAO 6-m telescope is presented. Some of these very rare objects (with currently known range of O/H of 7.12 < 12+log(O/H) < 7.65, or Zo/35 < Z < Zo/10) are believed to be the best proxies of `young' low-mass galaxies in the high-redshift Universe. One of the main goals of this study is to look for possible evidence of star formation (SF) activity induced by external perturbations. Recent results from HI mapping of a small subsample of XMD star-forming galaxies provided confident evidence for the important role of interaction-induced SF. Our observations provide complementary or new information that the great majority of the studied XMD dwarfs have strongly disturbed gas morphology and kinematics or the presence of detached components. We approximate the observed velocity fields by simple models of a rotating tilted thin disc, which allow us the robust detection of non-circular gas motions. These data, in turn, indicate the important role of current/recent interactions and mergers in the observed enhanced star formation. As a by-product of our observations, we obtained data for two LSB dwarf galaxies: Anon J012544+075957 that is a companion of the merger system UGC 993, and SAO 0822+3545 which shows off-centre, asymmetric, low SFR star-forming regions, likely induced by the interaction with the companion XMD dwarf HS 0822+3542.Comment: Accepted to MNRAS, 20 pages, 3 tables, 7 figure

    Quantum memory for non-stationary light fields based on controlled reversible inhomogeneous broadening

    Get PDF
    We propose a new method for efficient storage and recall of non-stationary light fields, e.g. single photon time-bin qubits, in optically dense atomic ensembles. Our approach to quantum memory is based on controlled, reversible, inhomogeneous broadening. We briefly discuss experimental realizations of our proposal.Comment: 4 page

    The optimal form of the scanning near-field optical microscopy probe

    Full text link
    A theoretical approach to determine the optimal form of the near-field optical microscope probe is proposed. An analytical expression of the optimal probe form with subwavelength aperture has been obtained. The advantages of the probe with the optimal form are illustrated using numerical calculations. The conducted calculations show 10 times greater light throughput and the reception possibility of the more compactly localized light at the output probe aperture which could indicate better spatial resolution of the optical images in near-field optical technique using optimal probe.Comment: 12 pages, 6 figure

    New Methods of Three-Dimensional Images Recognition Based on Stochastic Geometry and Functional Analysis

    Get PDF
    A new approach to 3D objects recognition based on modern methods of stochastic geometry and functional analysis is proposed in the paper. A detailed mathematical description of the method developed on the approach is also presented. The 3D trace transform allows creating an invariant description of spatial objects, which better resist distortion and coordinate noise than the one, obtained as a result of the object normalization procedure, does. The ability to control properties of developed features increases intellectual capacities of the 3D trace transform significantly, which can be mentioned as its undeniable advantage. The justification of the proposed theory and mathematical model is a variety of worked out theoretical examples of hypertriplet features that have particular described properties. The paper considers in detail scan techniques of the hypertrace transform and its mathematical model as well as approaches to developing and distinguishing informative features

    Structural and functional model of future craftsmen legal competence generation during professional education

    Full text link
    Formation of the law-governed state institutions in Russia, development of civil society, need for neutralizing the legal nihilism and generation of public legal culture, state demand for legally competent specialists, representing the public and social value, justify the relevancy of the investigated issue, on the one hand. On the other hand, it is determined by the necessity to perform and protect craft activity within the legal framework in compliance with the professional requirements, representing the personal value. Purpose of this article is to describe the progress of development and testing of structural and functional model of future craftsmen legal competence generation at the institutions of secondary professional education. The principle method to research the issue consists in simulation, which enables for representing the problem as process of task-oriented and deliberate mastering the legal competence by the future professionals during study at the institutions of secondary professional education. This article describes the structural and functional model of future craftsmen legal competence generation at the institutions of secondary professional education which consists of several interrelated components: target component, descriptive component, structuring and pragmatic component, evaluative and effective component; it determines a complex of pedagogical conditions facilitating the implementation of the model, develops a range of evaluation means to assess the level of the generated legal competence of the future craftsmen. Materials of this article can be useful for students learning the professions at the institutions of secondary professional education, for all categories of teachers and specialists in the field of professional craft education. © 2016 Romantsev et al

    Large-Area Scintillator Hodoscope with 50 ps Timing Resolution Onboard BESS

    Get PDF
    We describe the design and performance of a large-area scintillator hodoscope onboard the BESS rigidity spectrometer; an instrument with an acceptance of 0.3 m^{2}sr. The hodoscope is configured such that 10 and 12 counters are respectively situated in upper and lower layers. Each counter is viewed from its ends by 2.5 inch fine-mesh photomultiplier tubes placed in a stray magnetic field of 0.2 Tesla. Various beam-test data are presented. Use of cosmic-ray muons at ground-level confirmed 50 ps timing resolution for each layer, giving an overall time-of-flight resolution of 70 ps rms using a pure Gaussian resolution function. Comparison with previous measurements on a similar scintillator hodoscope indicates good agreement with the scaling law that timing resolution is proportional to 1/Npe\sqrt{N_{\rm pe}}, where NpeN_{\rm pe} is the effective number of photoelectrons.Comment: 16 pages, 14 figure

    Measurements of 0.2 to 20 GeV/n cosmic-ray proton and helium spectra from 1997 through 2002 with the BESS spectrometer

    Get PDF
    We measured low energy cosmic-ray proton and helium spectra in the kinetic energy range 0.215 - 21.5 GeV/n at different solar activities during a period from 1997 to 2002. The observations were carried out with the BESS spectrometer launched on a balloon at Lynn Lake, Canada. A calculation for the correction of secondary particle backgrounds from the overlying atmosphere was improved by using the measured spectra at small atmospheric depths ranging from 5 through 37 g/cm^2. The uncertainties including statistical and systematic errors of the obtained spectra at the top of atmosphere are 5-7 % for protons and 6-9 % for helium nuclei in the energy range 0.5 - 5 GeV/n.Comment: 27 pages, 7 Tables, 9 figures, Submitted to Astroparticle Physic

    Use of Physicochemical Method for Evaluation of Mucilage Producing Ability of the Linum Usitatissimum L. Seeds

    Get PDF
    Abstract In the modern medicine of many European countries flax is used as a medicament with a wide range of use. Wholesome effect of flax seeds is determined by the large amount of enveloping substances. This property is connected with content of mucilage up to 10% and glycoside linamarin. Flaxseed polysaccharides also possess antiinflammatory effect. Furthermore, mucilage production can be a chemosystematic characteric of intraspecific taxons. In literature intervarietal variability data is limited. Therefore, comparative evaluation of mucilage producing ability of flax seeds with different morphotypes is of interest. The research of micromorphological characteristics of seed coat and mucilage production dynamics was carried out and it was established that mucilage-producing cells are localized predominantly in the external layer of seed coat. It was established that Bahmalskiy, Nebesnyj, Kustanayskiy yantar varieties possess the highest level of mucilage production. Morphotype and varietal specificity of mucilage production are determined, consequently it can be used as a marker feature of L. usitatissimum new forms. The proposed technique is based on the determination of seed physicochemical characteristics and can be used for express analysis of the vegetal samples and their differentiation by the directions of use: as a fatty oil or mucilage-containing raw material. Keywords: Linum usitatissimum L. varieties, seeds, mucilage production, hydration dynamics, physicochemical method
    corecore