207,495 research outputs found
Severe storms Doppler lidar signal processing
The recommended algorithm for the correction of higher order data errors in severe storms doppler lidar signal processing is discussed
Research study: Severe storms Doppler lidar signal processing
Four tasks related to the signal processing aspects of the severe-storms Doppler lidar program are discussed. The development of algorithms for windfield retrieval from Doppler lidar measurements are discussed. Signal processor installation on a CV-990 aircraft is discussed
Windfield retrieval from Doppler lidar observations
An approach to the retrieval of a vector wind field from Doppler lidar observations is developed in general terms. The field of radial velocity measurements from each look angle is modeled by a smooth surface, the parameters of the model being determined from the data by least squares techniques. The vector wind field and higher-order fields are obtained from the two modeled surfaces. Estimated measurement errors are taken into account, and error estimates are available for all output data sets
High-temperature, long-life polyimide seals for hydraulic actuator rods
Two types of polyimide seals are developed for hydraulic actuator rod in low pressure second stage of two-stage configuration. Each seal melts test objectives of twenty million cycles of operation at 534 K. Analytical and experimental study results are discussed. Potential applications are given
Spectator Behavior in a Quantum Hall Antidot with Multiple Bound Modes
We theoretically study Aharonov-Bohm resonances in an antidot system with
multiple bound modes in the integer quantum Hall regime, taking capacitive
interactions between the modes into account. We find the spectator behavior
that the resonances of some modes disappear and instead are replaced by those
of other modes, due to internal charge relaxation between the modes. This
behavior is a possible origin of the features of previous experimental data
which remain unexplained, spectator behavior in an antidot molecule and
resonances in a single antidot with three modes.Comment: 4 pages, 3 figures, to be published in Physical Review Letter
On Inhomogeneity of a String Bit Model for Quantum Gravity
We study quantum gravitational effect on a two-dimensional open universe with
one particle by means of a string bit model. We find that matter is necessarily
homogeneously distributed if the influence of the particle on the size of the
universe is optimized.Comment: 16 pages, LaTeX2
Black hole as an Information Eraser
We discuss the identity of black hole entropy and show that the first law of
black hole thermodynamics, in the case of a Schwarzschild black hole, can be
derived from Landauer's principle by assuming that the black hole is one of the
most efficient information erasers in systems of a given temperature. The term
"most efficient" implies that minimal energy is required to erase a given
amount of information. We calculate the discrete mass spectra and the entropy
of a Schwarzschild black hole assuming that the black hole processes
information in unit of bits. The black hole entropy acquires a sub-leading
contribution proportional to the logarithm of its mass-squared in addition to
the usual mass-squared term without an artificial cutoff. We also argue that
the minimum of the black hole mass is .Comment: 12 pages, 4 figures, minor change
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Persistence of UK Real Estate returns: a Markov chain analysis
The persistence of investment performance is a topic of perennial interest to investors. Efficient Markets theory tells us that past performance can not be used to predict future performance yet investors appear to be influenced by the historical performance in making their investment allocation decisions. The problem has been of particular interest to investors in real estate; not least because reported returns from investment in real estate are serially correlated thus implying some persistence in investment performance. This paper applies the established approach of Markov Chain analysis to investigate the relationship between past and present performance of UK real estate over the period 1981 to 1996. The data are analysed by sector, region and size. Furthermore some variations in investment performance classification are reported and the results are shown to be robust
Gauge invariant generalization of the 2D chiral Gross-Neveu model
By means of the Lee-Shrock transformation we generalize the 2D Gross-Neveu
(GN) model to a U(1) gauge theory with charged fermion and scalar fields in
2D ( model). The model is equivalent to the
GN model at infinite gauge coupling. We show that the dynamical fermion
mass generation and asymptotic freedom in the effective four-fermion coupling
persist also when the gauge coupling decreases. These phenomena are not
influenced by the XY model phase transition at weak coupling. This suggests
that the model is in the same universality class as the GN
model and thus renormalizable.Comment: Contribution to Lattice 95, LaTeX file (4 pages), 4 ps-figures
appended (uuencoded), abstract correcte
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