15,628 research outputs found

    Hands-on haptics: exploring non-visual visualization using the sense of touch

    Get PDF
    No abstract available

    Feeling what you hear: tactile feedback for navigation of audio graphs

    Get PDF
    Access to digitally stored numerical data is currently very limited for sight impaired people. Graphs and visualizations are often used to analyze relationships between numerical data, but the current methods of accessing them are highly visually mediated. Representing data using audio feedback is a common method of making data more accessible, but methods of navigating and accessing the data are often serial in nature and laborious. Tactile or haptic displays could be used to provide additional feedback to support a point-and-click type interaction for the visually impaired. A requirements capture conducted with sight impaired computer users produced a review of current accessibility technologies, and guidelines were extracted for using tactile feedback to aid navigation. The results of a qualitative evaluation with a prototype interface are also presented. Providing an absolute position input device and tactile feedback allowed the users to explore the graph using tactile and proprioceptive cues in a manner analogous to point-and-click techniques

    Thermogravimetric instrument

    Get PDF
    Thermogravimetric instrument to measure volatility under both isothermal and nonisothermal conditions and to study thermal decompositio

    Conclusion of Viking Lander Imaging Investigation: Picture catalog of experiment data record

    Get PDF
    The images returned by the two Viking landers during the Viking Survey Mission are presented in this report. Listing of supplemental information which describe the conditions under which the images were acquired are included. Subsets of the images are listed in a variety of sequences to aid in locating images of interest. The format and organization of the digital magnetic tape storage of the images are described. A brief description of the mission and the camera system is also included

    Single-color two-photon spectroscopy of Rydberg states in electric fields

    Get PDF
    Rydberg states of atomic helium with principal quantum numbers ranging from n=20 to n=100 have been prepared by non-resonance-enhanced single-color two-photon excitation from the metastable 2 {^3}S{_1} state. Photoexcitation was carried out using linearly and circularly polarized pulsed laser radiation. In the case of excitation with circularly polarized radiation, Rydberg states with azimuthal quantum number |m_{\ell}|=2 were prepared in zero electric field, and in homogeneous electric fields oriented parallel to the propagation axis of the laser radiation. In sufficiently strong electric fields, individual Rydberg-Stark states were resolved spectroscopically, highlighting the suitability of non-resonance-enhanced multiphoton excitation schemes for the preparation of long-lived high-|m_{\ell}| hydrogenic Rydberg states for deceleration and trapping experiments. Applications of similar schemes for Doppler-free excitation of positronium atoms to Rydberg states are also discussed

    Adoption of Conservation Agriculture Technologies by Smallholder Farmers in the Shamva District of Zimbabwe: A Tobit application

    Get PDF
    Conventional agricultural practices such as the use of the moldboard plough are no longer sustainable due to their extensive soil degradation effects. As a panacea, several Conservation Agriculture (CA) technologies have been promoted to improve soil structure and water conservation. However, adoption of these technologies has been resisted by smallholder farmers and identifying causes of the low adoption rates to facilitate intervention strategies remains a challenge to development practitioners. Using data from 100 farmers, this paper uses a Tobit application to assess the underlying factors important in determining farmers’ adoption of zero-tillage, crop rotation and contour ridging technologies. Empirical results suggest that adoption and use intensity of each of these technologies is affected by a set of distinct household factors. There is also evidence to show complementarities in adoption and use of these technologies, suggesting the need to tailor awareness and promotional strategies depending on the technology in question and socio-economic background of target farmers.Conservation Agriculture (CA), Conventional Farming (CF) technology, Tobit Model, Adoption, Agricultural and Food Policy, Community/Rural/Urban Development, Farm Management,

    Second Law Violations in Lovelock Gravity for Black Hole Mergers

    Full text link
    We study the classical second law of black hole thermodynamics, for Lovelock theories (other than General Relativity), in arbitrary dimensions. Using the standard formula for black hole entropy, we construct scenarios involving the merger of two black holes in which the entropy instantaneously decreases. Our construction involves a Kaluza-Klein compactification down to a dimension in which one of the Lovelock terms is topological. We discuss some open issues in the definition of the second law which might be used to compensate this entropy decrease.Comment: 15 pages, 1 figure, v2 Title change & minor revisions to match published version, v3 fixed accidental deletion of author name

    Variance and Skewness in the FIRST survey

    Get PDF
    We investigate the large-scale clustering of radio sources in the FIRST 1.4-GHz survey by analysing the distribution function (counts in cells). We select a reliable sample from the the FIRST catalogue, paying particular attention to the problem of how to define single radio sources from the multiple components listed. We also consider the incompleteness of the catalogue. We estimate the angular two-point correlation function w(θ)w(\theta), the variance Ψ2\Psi_2, and skewness Ψ3\Psi_3 of the distribution for the various sub-samples chosen on different criteria. Both w(θ)w(\theta) and Ψ2\Psi_2 show power-law behaviour with an amplitude corresponding a spatial correlation length of r010h1r_0 \sim 10 h^{-1}Mpc. We detect significant skewness in the distribution, the first such detection in radio surveys. This skewness is found to be related to the variance through Ψ3=S3(Ψ2)α\Psi_3=S_3(\Psi_2)^{\alpha}, with α=1.9±0.1\alpha=1.9\pm 0.1, consistent with the non-linear gravitational growth of perturbations from primordial Gaussian initial conditions. We show that the amplitude of variance and skewness are consistent with realistic models of galaxy clustering.Comment: 13 pages, 21 inline figures, to appear in MNRA
    corecore