5,841 research outputs found
he geometry of statistical efficiency
We will place certain parts of the theory of statistical efficiency into the author’s
operator trigonometry (1967), thereby providing new geometrical understanding
of statistical efficiency. Important earlier results of Bloomfield
and Watson, Durbin and Kendall, Rao and Rao, will be so interpreted. For
example, worse case relative least squares efficiency corresponds to and is
achieved by the maximal turning antieigenvectors of the covariance matrix.
Some little-known historical perspectives will also be exposed. The overall
view will be emphasized
Optical diodes
Research on metal-barrier-metal structures is reviewed. Topics discussed include: demonstration of antenna coupling and rectification characteristics with high resistance evaporated structures at a wavelength of 10 microns; application of these devices to coherent conversion of laser radiation and infrared and optical circuit elements; and comparison of the point-contact type of diode structure and the newly developed photolithographic structures
Development and evaluation of braze alloys for vacuum furnace brazing
Copper and copper-base alloys tested for use in vacuum furnace brazing of rocket engine tubular thrust chamber
Collaborative research in tunneling and field emission pumped surface wave local oscillators and amplifiers for infrared and submillimeter wavelengths under director's discretionary fund
Progress is reported in work towards the development of surface wave sources for the infrared and sub-millimeter portion of the spectrum to be based upon electron pumping by tunneling electrons in metal-barrier-metal or metal-barrier-semiconductor devices. Tunneling phenomena and the coupling of radiation to tunnel junctions were studied. The propagation characteristics of surface electro-magnetic modes in metal-insulator-p(++) semiconductor structures as a function of frequency were calculated. A model for the gain process based upon Tucker's formalism was developed and used to estimate what low frequency gain might be expected from such structures. The question of gain was addressed from a more fundamental viewpoint using the method of Lasher and Stern
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The intelligence cycle is dead, long live the intelligence cycle: Rethinking intelligence fundamentals for a new intelligence doctrine
In the spring of 2009 the UK Ministry of Defence elected to undertake a review of the existing military Joint Intelligence Doctrine. The existing doctrine, Joint Warfare Doctrine 2-00 (JWP 2-00) Intelligence Support to Joint Operations had been promulgated in 2003 largely on the basis of coalition-oriented expeditionary and peace support operations in the Balkans, Middle East and Afghanistan. This had replaced an earlier, first edition of JWP 2-00 issued in 1999
Global dispersive solutions for the Gross-Pitaevskii equation in two and three dimensions
We study asymptotic behaviour at time infinity of solutions close to the
non-zero constant equilibrium for the Gross-Pitaevskii equation in two and
three spatial dimensions. We construct a class of global solutions with
prescribed dispersive asymptotic behavior, which is given in terms of the
linearized evolution
Nondiffusive suprathermal ion transport in simple magnetized toroidal plasmas
We investigate suprathermal ion dynamics in simple magnetized toroidal
plasmas in the pres- ence of electrostatic turbulence driven by the ideal
interchange instability. Turbulent fields from fluid simulations are used in
the non-relativistic equation of ion motion to compute suprathermal tracer ion
trajectories. Suprathermal ion dispersion starts with a brief ballistic phase,
during which particles do not interact with the plasma, followed by a
turbulence interaction phase. In this one simple system, we observe the entire
spectrum of suprathermal ion dynamics, from subdiffusion to superdiffusion,
depending on beam energy and turbulence amplitude. We estimate the duration of
the ballistic phase and identify basic mechanisms during the interaction phase
that determine the character of suprathermal ion dispersion upon the beam
energy and turbulence fluctuation amplitude.Comment: 5 pages, 3 figures, accepted in PR
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