110,790 research outputs found
Improved Heterogeneous Distance Functions
Instance-based learning techniques typically handle continuous and linear
input values well, but often do not handle nominal input attributes
appropriately. The Value Difference Metric (VDM) was designed to find
reasonable distance values between nominal attribute values, but it largely
ignores continuous attributes, requiring discretization to map continuous
values into nominal values. This paper proposes three new heterogeneous
distance functions, called the Heterogeneous Value Difference Metric (HVDM),
the Interpolated Value Difference Metric (IVDM), and the Windowed Value
Difference Metric (WVDM). These new distance functions are designed to handle
applications with nominal attributes, continuous attributes, or both. In
experiments on 48 applications the new distance metrics achieve higher
classification accuracy on average than three previous distance functions on
those datasets that have both nominal and continuous attributes.Comment: See http://www.jair.org/ for an online appendix and other files
accompanying this articl
Fabrication process of a high temperature polymer matrix engine duct
The process that was used in the molding of an advanced composite outer by-pass duct planned for the F404 engine is discussed. This duct was developed as a potential replacement for the existing titanium duct in order to reduce both the weight and cost of the duct. The composite duct is now going into the manufacturing technology portion of the program. The duct is fabricated using graphite cloth impregnated with the PMR-15 matrix system
Neutrino Annihilation between Binary Neutron Stars
We calculate the neutrino pair annihilation rate into electron pairs between
two neutron stars in a binary system. We present a closed formula for the
energy deposition rate at any point between the stars, where each neutrino of a
pair derives from each star, and compare this result to that where all
neutrinos derive from a single neutron star. An approximate generalization of
this formula is given to include the relativistic effects of gravity. We find
that this inter-star neutrino annihilation is a significant contributor to the
energy deposition between heated neutron star binaries. In particular, for two
neutron stars near their last stable orbit, inter-star neutrino annihilation
energy deposition is almost equal to that of single star energy deposition.Comment: 15 pages, 6 figures, accepted for publication in The Astrophysical
Journa
Decay channels and charmonium mass-shifts
The discovery in the last few years of the and states of the
extended charmonium family has highlighted the importance of the closeness of
decay channels to an understanding of these mesons. We aid this debate by
illustrating a simple calculational procedure for including the effect of open
and nearby closed channels.Comment: 4 pages, 2 figures Revised version: (1) corrected 2 typos in Table
II, (2) additional text in penultimate paragraph to clarify the calculation
of mass-shifts for and . We thank colleagues for pointing
out confusing wording of previous tex
General Relativistic Augmentation of Neutrino Pair Annihilation Energy Deposition Near Neutron Stars
General relativistic calculations are made of neutrino-antineutrino
annihilation into electron-positron pairs near the surface of a neutron star.
It is found that the efficiency of this process is enhanced over the Newtonian
values up to a factor of more than 4 in the regime applicable to Type II
supernovae and by up to a factor of 30 for collapsing neutron stars.Comment: 14 pages, 6 figure
A numerical study exploring the effect of particle properties on the fluidization of adhesive particles
Wave Energy Amplification in a Metamaterial based Traveling Wave Structure
We consider the interaction between a particle beam and a propagating
electromagnetic wave in the presence of a metamaterial. We show that the
introduction of a metamaterial gives rise to a novel dispersion curve which
determines a unique wave particle relationship, via the frequency dependence of
the metamaterial and the novel ability of metamaterials to exhibit simultaneous
negative permittivity and permeability. Using a modified form of Madey's
theorem we find that the novel dispersion of the metamaterial leads to a
amplification of the EM wave power
Behavior of composite bolted joints at elevated temperature
Experimental results from an investigation which examines the combined effects of temperature, joint geometry and out-of-plane constraint upon the response of mechanically fastened composite joints are presented. Data are presented for simulated mechanically fastened joint conditions in two laminate configurations fabricated from Hercules AS/3501-6 graphite-epoxy. Strength and failure mode results are presented for the test temperatures of 21 C, 121 C and 177 C and for a range of the geometric parameters W/D and e/D from 3.71 to 7.43 and 1.85 to 3.69, respectively. A hole diameter, D of 5.16 mm was utilized for all tests. Pin bearing tests with out-of-plane constraint were conducted at room temperature only. All elevated temperature data were generated for pin bearing conditions. Ultrasonic C scan inspection of the failed specimens was employed to assess the damage region and to determine failure mode. Comparative data are presented for pin bearing and out-of-plane constraint conditions for the above mentioned joint configurations. The joint under pin loading was modeled by two dimensional finite element methods. Predicted net section strain concentrations were compared with experimental results
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