منابع مشابه
Statistical Stability in Time Reversal
When a signal is emitted from a source, recorded by an array of transducers, time reversed and re-emitted into the medium, it will refocus approximately on the source location. We analyze the refocusing resolution in a high frequency, remote sensing regime, and show that, because of multiple scattering, in an inhomogeneous or random medium it can improve beyond the diffraction limit. We also sh...
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Localization of targets imbedded in a heterogeneous background medium is a common problem in seismic, ultrasonic, and electromagnetic imaging problems. The best imaging techniques make direct use of the eigenfunctions and eigenvalues of the array response matrix, as recent work on time-reversal acoustics has shown. Of the various imaging functionals studied, one that is representative of a pref...
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Abstract. In the National Statistical Systems, some parts of the official statistics required for development planning and evidence base management are collected through sampling survey. Due to the high cost of sampling process, as well as nonresponses, it may not be possible to collect all of the expected variables in a survey.In order to obtain a comprehensive and complete source o...
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Richard Feynman has claimed that anti-particles are nothing but particles ‘propagating backwards in time’; that time reversing a particle state always turns it into the corresponding anti-particle state. According to standard quantum field theory textbooks this is not so: time reversal does not turn particles into anti-particles. Feynman’s view is interesting because, in particular, it suggests...
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Time reversal invariance can be summarised as follows: no difference can be measured if a sequence of events is run forward or backward in time. Because price time series are dominated by a randomness that hides possible structures and orders, the existence of time reversal invariance requires care to be investigated. Different statistics are constructed with the property to be zero for time se...
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ژورنال
عنوان ژورنال: SIAM Journal on Applied Mathematics
سال: 2004
ISSN: 0036-1399,1095-712X
DOI: 10.1137/s0036139902411107