2,176 research outputs found
MIDAS, prototype Multivariate Interactive Digital Analysis System for large area earth resources surveys. Volume 1: System description
A third-generation, fast, low cost, multispectral recognition system (MIDAS) able to keep pace with the large quantity and high rates of data acquisition from large regions with present and projected sensots is described. The program can process a complete ERTS frame in forty seconds and provide a color map of sixteen constituent categories in a few minutes. A principle objective of the MIDAS program is to provide a system well interfaced with the human operator and thus to obtain large overall reductions in turn-around time and significant gains in throughput. The hardware and software generated in the overall program is described. The system contains a midi-computer to control the various high speed processing elements in the data path, a preprocessor to condition data, and a classifier which implements an all digital prototype multivariate Gaussian maximum likelihood or a Bayesian decision algorithm. Sufficient software was developed to perform signature extraction, control the preprocessor, compute classifier coefficients, control the classifier operation, operate the color display and printer, and diagnose operation
MIDAS, prototype Multivariate Interactive Digital Analysis System, Phase 1. Volume 2: Diagnostic system
The MIDAS System is a third-generation, fast, multispectral recognition system able to keep pace with the large quantity and high rates of data acquisition from present and projected sensors. A principal objective of the MIDAS Program is to provide a system well interfaced with the human operator and thus to obtain large overall reductions in turn-around time and significant gains in throughout. The hardware and software generated in Phase I of the over-all program are described. The system contains a mini-computer to control the various high-speed processing elements in the data path and a classifier which implements an all-digital prototype multivariate-Gaussian maximum likelihood decision algorithm operating 2 x 105 pixels/sec. Sufficient hardware was developed to perform signature extraction from computer-compatible tapes, compute classifier coefficients, control the classifier operation, and diagnose operation. Diagnostic programs used to test MIDAS' operations are presented
Measurement of CP Violation at the without Time Ordering or
I derive the expressions for the CP-violating asymmetry arising from
interference between mixed and direct decays in the Upsilon(4S) system, for the
case in which only one of the B decay times is observed, integrating over the
decay time of the other B. I observe that neither the difference of the decay
times Delta t, nor even their time-ordering, need be detected. A technique for
measurement of the CP-violating weak decay parameter sin(2beta) is described
which exploits this observation.Comment: 9 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLN
The General Theory of Quantum Field Mixing
We present a general theory of mixing for an arbitrary number of fields with
integer or half-integer spin. The time dynamics of the interacting fields is
solved and the Fock space for interacting fields is explicitly constructed. The
unitary inequivalence of the Fock space of base (unmixed) eigenstates and the
physical mixed eigenstates is shown by a straightforward algebraic method for
any number of flavors in boson or fermion statistics. The oscillation formulas
based on the nonperturbative vacuum are derived in a unified general
formulation and then applied to both two and three flavor cases. Especially,
the mixing of spin-1 (vector) mesons and the CKM mixing phenomena in the
Standard Model are discussed emphasizing the nonperturbative vacuum effect in
quantum field theory
Quantum Field Theory of Meson Mixing
We have developed a quantum field theoretic framework for scalar and
pseudoscalar meson mixing and oscillations in time. The unitary inequivalence
of the Fock space of base (unmixed) eigenstates and the physical mixed
eigenstates is proven and shown to lead to a rich condensate structure. This is
exploited to develop formulas for two flavor boson oscillations in systems of
arbitrary boson occupation number. The mixing and oscillation can be understood
in terms of vacuum condensate which interacts with the bare particles to induce
non-trivial effects. We apply these formulas to analyze the mixing of
with and comment on the system. In addition, we consider the
mixing of boson coherent states, which may have future applications in the
construction of meson lasers.Comment: 12 pages, 3 figures; Eqs.(10-12) corrected, leading to new physical
insights; added paragraph under Eq.(24) explaining physical interpretation of
mixing in terms of vacuum condensation; references added and minor typo
correcte
Planar rotational magnetic micromotors with integrated shaft encoder and magnetic rotor levitation
Deep x-ray lithography and electroplating may be combined to form a fabrication tool for micromechanical devices with large structural heights, to 500 micron, and extreme edge acuities, less than 0.1 micron-run-out per 100 micron of height. This process concept which originated in Germany as LIGA may be further extended by adding surface micromachining. This extension permits the fabrication of precision metal and plastic parts which may be assembled into three-dimensional micromechanical components and systems. The processing tool may be used to fabricate devices from ferromagnetic material such as nickel and nickel-iron alloys. These materials when properly heat treated exhibit acceptable magnetic behavior for current to flux conversion and marginal behavior for permanent magnet applications. The tool and materials have been tested via planar, magnetic, rotational micromotor fabrication. Three phase reluctance machines of the 6:4 configuration with 280 micron diameter rotors have been tested and analyzed. Stable rotational speeds to 34,000 rpm with output torques above 10 x 10(exp -9) N-m have been obtained. The behavior is monitored with integrated shaft encoders which are photodiodes which measure the rotor response. Magnetic levitation of the rotor via reluctance forces has been achieved and has reduced frictional torque losses to less than 1 percent of the available torque. The results indicate that high speed limits of these actuators are related to torque ripple. Hysteresis motors with magnetic bearings are under consideration and will produce high speed rotational machines with excellent sensor application potential
Atrial fibrillation impairs the diagnostic performance of cardiac natriuretic peptides in dyspneic patients. results from the BACH Study (Biomarkers in ACute Heart Failure)
Objectives: The purpose of this study was to assess the impact of atrial fibrillation (AF) on the performance of mid-region amino terminal pro-atrial natriuretic peptide (MR-proANP) in comparison with the B-type peptides (BNP and NT-proBNP) for diagnosis of acute heart failure (HF) in dyspneic patients. Background: The effects of AF on the diagnostic and prognostic performance of MR-proANP in comparison with the B type natriuretic peptides have not been previously reported. Methods: A total of 1,445 patients attending the emergency department with acute dyspnea had measurements taken of MR-proANP, BNP, and NT-proBNP values on enrollment to the BACH trial and were grouped according to presence or absence of AF and HF. Results: AF was present in 242 patients. Plasma concentrations of all three peptides were lowest in those with neither AF nor HF and AF without HF was associated with markedly increased levels (p < 0.00001). HF with or without AF was associated with a significant further increment (p < 0.00001 for all three markers). Areas under receiver operator characteristic curves (AUCs) for discrimination of acute HF were similar and powerful for all peptides without AF (0.893 to 0.912; all p < 0.001) with substantial and similar reductions (0.701 to 0.757) in the presence of AF. All 3 peptides were independently prognostic but there was no interaction between any peptide and AF for prediction of all-cause mortality. Conclusions: AF is associated with increased plasma natriuretic peptide (MR-proANP, BNP and NT-proBNP) levels in the absence of HF. The diagnostic performance of all three peptides is impaired by AF. This warrants consideration of adjusted peptide thresholds for diagnostic use in AF and mandates the continued search for markers free of confounding by AF
Determining the Weak Phase From Charged Decays
A quadrangle relation is shown to be satisfied by the amplitudes for , and . By comparison with the
corresponding relation satisfied by decay amplitudes, it is shown that
the relative phases of all the amplitudes can be determined up to discrete
ambiguities. Making use of an SU(3) relation between amplitudes contributing to
the above decays and those contributing to , it is
then shown that one can determine the weak phase , where is the Cabibbo-Kobayashi-Maskawa
matrix describing the charge-changing weak interactions between the quarks
and .Comment: 16 pages, latex, 7 uuencoded figure
Weak Phase From Ratio of Rates
The ratio of partial decay rates for charged and neutral mesons to final states provides information on the weak phase when augmented with information on the CP-violating asymmetry
in the mode. The requirements for a useful determination of
are examined in the light of present information about the decays , , and the corresponding charge-conjugate
modes. The effects of electroweak penguins and rescattering corrections are
noted, and proposals are made for estimating and measuring their importance.Comment: 16 pages, latex, 3 figures, revised version sent to Phys. Rev.
Combining CP Asymmetries in Decays
We prove an approximate relation, to leading order in dominant terms, between
CP-violating rate differences in and
. We show how data from these two processes may be
combined in order to enhance the significance of a nonzero result.Comment: 9 pages, latex, no figures, submitted to Phys. Rev. Letters, revise
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