31,582 research outputs found

    Earth feature identification for onboard multispectral data editing: Computational experiments

    Get PDF
    A computational model of the processes involved in multispectral remote sensing and data classification is developed as a tool for designing smart sensors which can process, edit, and classify the data that they acquire. An evaluation of sensor system performance and design tradeoffs involves classification rates and errors as a function of number and location of spectral channels, radiometric sensitivity and calibration accuracy, target discrimination assignments, and accuracy and frequency of compensation for imaging conditions. This model provides a link between the radiometric and statistical properties of the signals to be classified and the performance characteristics of electro-optical sensors and data processing devices. Preliminary computational results are presented which illustrate the editing performance of several remote sensing approaches

    J. R. Hicks and R. O. Leary to J. E. Davis, 9 May

    Get PDF
    Regarding medical supplies and services from Dr. E.G. Banks for part of the year 1863. Includes undated envelope.https://egrove.olemiss.edu/ciwar_corresp/1050/thumbnail.jp

    LANDSAT-D investigations in snow hydrology

    Get PDF
    Work undertaken during the contract and its results are described. Many of the results from this investigation are available in journal or conference proceedings literature - published, accepted for publication, or submitted for publication. For these the reference and the abstract are given. Those results that have not yet been submitted separately for publication are described in detail. Accomplishments during the contract period are summarized as follows: (1) analysis of the snow reflectance characteristics of the LANDSAT Thematic Mapper, including spectral suitability, dynamic range, and spectral resolution; (2) development of a variety of atmospheric models for use with LANDSAT Thematic Mapper data. These include a simple but fast two-stream approximation for inhomogeneous atmospheres over irregular surfaces, and a doubling model for calculation of the angular distribution of spectral radiance at any level in an plane-parallel atmosphere; (3) incorporation of digital elevation data into the atmospheric models and into the analysis of the satellite data; and (4) textural analysis of the spatial distribution of snow cover

    DISTRIBUTIVE INJUSTICE: A PREDICTIVE STUDY OF CORRUPTION AND OFFICE ABUSE AMONG POLICE OFFICERS IN ANAMBRA STATE POLICE COMMAND, NIGERIA

    Get PDF
    This paper explored the predictive effects of distributive injustice on corruption and office abuse among police officers in Anambra State Police Command. The participants of the study were 294 (two hundred and ninety four) junior cadre police officers (below the rank of Assistant Superintendent of Police) who comprised 241 male-police officers and 53 female-police officers. The ages of the police officers ranged from 26 to 47 years, the mean age was 37.51 years with a standard deviation of 2.20. Data for the study was collected with the aid of organizational justice scale by Niehoff and Moorman (1993) and Unethical Behaviour Tendency Scale by Tang and Weatherford (1997). Predictive design and multiple regression analysis were adopted as the design and statistical tool for the study respectively. The result confirmed that both corruption and office abuse dimensions of unethical behaviour were significantly predicted by distributive injustice among junior cadre police officers.  Article visualizations

    Quantum whistling in superfluid 4He

    Full text link
    Fundamental considerations predict that macroscopic quantum systems such as superfluids and the electrons in superconductors will exhibit oscillatory motion when pushed through a small constriction. Here we report the observation of these oscillations between two reservoirs of superfluid 4He partitioned by an array of nanometer-sized apertures. They obey the Josephson frequency equation and are coherent amongst all the apertures. This discovery at the relatively high temperature of 2K (2000 times higher than related phenomena in 3He) may pave the way for a new class of practical rotation sensors of unprecedented precision.Comment: 6 pages, 3 figures, to be published in Natur

    Dissipative dynamics of vortex arrays in trapped Bose-condensed gases: neutron stars physics on μ\muK scale

    Full text link
    We develop a theory of dissipative dynamics of large vortex arrays in trapped Bose-condensed gases. We show that in a static trap the interaction of the vortex array with thermal excitations leads to a non-exponential decay of the vortex structure, and the characteristic lifetime depends on the initial density of vortices. Drawing an analogy with physics of pulsar glitches, we propose an experiment which employs the heating of the thermal cloud in the course of the decay of the vortex array as a tool for a non-destructive study of the vortex dynamics.Comment: 4 pages, revtex; revised versio

    Dissipative dynamics of a kink state in a Bose-condensed gas

    Full text link
    We develop a theory of dissipative dynamics of a kink state in a finite-temperature Bose-condensed gas. We find that due to the interaction with the thermal cloud the kink state accelerates towards the velocity of sound and continuously transforms to the ground-state condensate. We calculate the life-time of a kink state in a trapped gas and discuss possible experimental implications.Comment: 4 pages, RevTe

    Strong Coupling Corrections to the Ginzburg-Landau Theory of Superfluid ^{3}He

    Full text link
    In the Ginzburg-Landau theory of superfluid 3^{3}He, the free energy is expressed as an expansion of invariants of a complex order parameter. Strong coupling effects, which increase with increasing pressure, are embodied in the set of coefficients of these order parameter invariants\cite{Leg75,Thu87}. Experiments can be used to determine four independent combinations of the coefficients of the five fourth order invariants. This leaves the phenomenological description of the thermodynamics near TcT_{c} incomplete. Theoretical understanding of these coefficients is also quite limited. We analyze our measurements of the magnetic susceptibility and the NMR frequency shift in the BB-phase which refine the four experimental inputs to the phenomenological theory. We propose a model based on existing experiments, combined with calculations by Sauls and Serene\cite{Sau81} of the pressure dependence of these coefficients, in order to determine all five fourth order terms. This model leads us to a better understanding of the thermodynamics of superfluid 3^{3}He in its various states. We discuss the surface tension of bulk superfluid 3^{3}He and predictions for novel states of the superfluid such as those that are stabilized by elastic scattering of quasiparticles from a highly porous silica aerogel.Comment: 9 pages, 7 figures, 2 table
    corecore