28,448 research outputs found
Evaluation of algorithms for estimating wheat acreage from multispectral scanner data
The author has identified the following significant results. Fourteen different classification algorithms were tested for their ability to estimate the proportion of wheat in an area. For some algorithms, accuracy of classification in field centers was observed. The data base consisted of ground truth and LANDSAT data from 55 sections (1 x 1 mile) from five LACIE intensive test sites in Kansas and Texas. Signatures obtained from training fields selected at random from the ground truth were generally representative of the data distribution patterns. LIMMIX, an algorithm that chooses a pure signature when the data point is close enough to a signature mean and otherwise chooses the best mixture of a pair of signatures, reduced the average absolute error to 6.1% and the bias to 1.0%. QRULE run with a null test achieved a similar reduction
Determining DfT Hardware by VHDL-AMS Fault Simulation for Biological Micro-Electronic Fluidic Arrays
The interest of microelectronic fluidic arrays for biomedical applications, like DNA determination, is rapidly increasing. In order to evaluate these systems in terms of required Design-for-Test structures, fault simulations in both fluidic and electronic domains are necessary. VHDL-AMS can be used successfully in this case. This paper shows a highly testable architecture of a DNA Bio-Sensing array, its basic sensing concept, fluidic modeling and sensitivity analysis. The overall VHDL-AMS fault simulation of the system is shown
Improvement in the geopotential derived from satellite and surface data (GEM 7 and 8)
A refinement was obtained in the earth's gravitational field using satellite and surface data. In addition to a more complete treatment of data previously employed on 27 satellites, the new satellite solution (Goddard Earth Model 7) includes 64,000 laser measurements taken on 7 satellites during the international satellite geodesy experiment (ISAGEX) program. The GEM 7, containing 400 harmonic terms, is complete through degree and order 16. The companion solution GEM 8 combines the same satellite data as in GEM 7 with surface gravimetry over 39% of the earth. The GEM 8 is complete to degree and order 25. Extensive tests on data independent of the solution show that the undulation of the geoidal surface computed by GEM 7 has an accuracy of about 3m (rms). The overall accuracy of the geoid estimated by GEM 8 is estimated to be about 4-1/4m (rms), an improvement of almost 1m over previous solutions
The multilevel pairing Hamiltonian versus the degenerate case
We study the pairing Hamiltonian in a set of non degenerate levels. First, we
review in the path integral framework the spontaneous breaking of the U(1)
symmetry occurring in such a system for the degenerate situation. Then the
behaviors with the coupling constant of the ground state energy in the
multilevel and in the degenerate case are compared. Next we discuss, in the
multilevel case, an exact strong coupling expansion for the ground state energy
which introduces the moments of the single particle level distribution. The
domain of validity of the expansion, which is known in the macroscopic limit,
is explored for finite systems and its implications for the energy of the
latter is discussed. Finally the seniority and Gaudin excitations of the
pairing Hamiltonian are addressed and shown to display the same gap in leading
order.Comment: 20 pages, 4 figure
Goddard earth models (5 and 6)
A comprehensive earth model has been developed that consists of two complementary gravitational fields and center-of-mass locations for 134 tracking stations on the earth's surface. One gravitational field is derived solely from satellite tracking data. This data on 27 satellite orbits is the most extensive used for such a solution. A second solution uses this data with 13,400 simultaneous events from satellite camera observations and surface gravimetric anomalies. The satellite-only solution as a whole is accurate to about 4.5 milligals as judged by the surface gravity data. The majority of the station coordinates are accurate to better than 10 meters as judged by independent results from geodetic surveys and by Doppler tracking of both distant space probes and near earth orbits
A systematic review of worldwide cancer nursing research: 1994 to 2003
Kelly contributed to the conduct and choice of papers for the study, carried out a systematic review of one sixth of all the papers, contributed to the conclusion and helped to edit the final version of this paper
Microstructured optical fibres for gas sensing: design fabrication and post-fab processing
Air/silica Microstructured Optical Fibers (MOFs) offer new prospects for fiber based sensor devices. In this paper, two topics of particular significance for gas sensing using air guiding Photonic Bandgap Fibers (PBGFs) are discussed. First, we address the issue of controlling the modal properties of PBGFs and demonstrate a single mode, polarization maintaining air guiding PBGF. Secondly, we present recent improvements of a femtosecond laser machining technique for fabricating fluidic channels in PBGFs, which allowed us to achieve cells with multiple side access channels and low additional loss
Chemical effects of photonuclear reactions in the propyl bromides
When nuclear reactions occur in atoms in molecules chemical changes follow as a result of the recoil of the product atoms. The nature of these chemical changes has been studied intensively for a number of systems but in most cases the magnitude of the recoil energy has been about the same. In the present studies use was made of a much greater recoil energy than that normally used. The reaction Br(γ,η)Br* gives a recoil bromine2 atom with an energy of the order 105ev, compared to 102ev for the product of the Br(η,γ)Br* reaction which is usually used
Modular converter system for low-cost off-grid energy storage using second life Li-ion batteries
Lithium ion batteries are promising for small off- grid energy storage
applications in developing countries because of their high energy density and
long life. However, costs are prohibitive. Instead, we consider 'used' Li-ion
batteries for this application, finding experimentally that many discarded
laptop cells, for example, still have good capacity and cycle life. In order to
make safe and optimal use of such cells, we present a modular power management
system using a separate power converter for every cell. This novel approach
allows individual batteries to be used to their full capacity. The power
converters operate in voltage droop control mode to provide easy charge
balancing and implement a battery management system to estimate the capacity of
each cell, as we demonstrate experimentally.Comment: Presented at IEEE GHTC Oct 10-14, 2014, Silicon Valle
Thermodynamic properties of a small superconducting grain
The reduced BCS Hamiltonian for a metallic grain with a finite number of
electrons is considered. The crossover between the ultrasmall regime, in which
the level spacing, , is larger than the bulk superconducting gap, ,
and the small regime, where , is investigated analytically
and numerically. The condensation energy, spin magnetization and tunneling peak
spectrum are calculated analytically in the ultrasmall regime, using an
approximation controlled by as small parameter, where is the
number of interacting electron pairs. The condensation energy in this regime is
perturbative in the coupling constant , and is proportional to . We find that also in a large regime with
, in which pairing correlations are already rather well developed,
the perturbative part of the condensation energy is larger than the singular,
BCS, part. The condition for the condensation energy to be well approximated by
the BCS result is found to be roughly . We show how
the condensation energy can, in principle, be extracted from a measurement of
the spin magnetization curve, and find a re-entrant susceptibility at zero
temperature as a function of magnetic field, which can serve as a sensitive
probe for the existence of superconducting correlations in ultrasmall grains.
Numerical results are presented which suggest that in the large limit the
1/N correction to the BCS result for the condensation energy is larger than
.Comment: 17 pages, 7 figures, Submitted to Phys. Rev.
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