Presents the mathematical study of approaches for defining nested arrays in APL, a computer program language. Discussion on the extension of data structure capability of APL; Data structure of APL; Characteristics of ...
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Presents the mathematical study of approaches for defining nested arrays in APL, a computer program language. Discussion on the extension of data structure capability of APL; Data structure of APL; Characteristics of APL; Function of APL as an algorithm notation.
In this paper, we link the discrete Fourier transform(DFT) with spatial smoothing method for the problem of direction of arrival(DOA) estimation with nested arrays and proposed a neoteric algorithm. The existing algor...
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In this paper, we link the discrete Fourier transform(DFT) with spatial smoothing method for the problem of direction of arrival(DOA) estimation with nested arrays and proposed a neoteric algorithm. The existing algorithms with nested arrays based on spatial smoothing method are effective, but essentially suffer from searching peaks being in whole sector. To solve the problem above, we first vectorize the covariance matrix of the received signal to acquire the observation vector that behaves like an extended received signal of a much longer array. We second exploit DFT method to achieve the coarse initial DOA estimates. Finally, according to the spatial smoothing MUSIC algorithm, we acquire the angle estimation by peak searching around the coarse initial DOA estimates. Simulation results validate the superiority of the proposed method in DOA estimation performance, as compared to the existing spatial smoothing MUSIC algorithm with nested array.
One-bit quantization has become an important topic in massive MIMO systems, as it offers low cost and low complexity in the implementation. Techniques to achieve high performance in spite of the coarse quantizers have...
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ISBN:
(纸本)9781509041183
One-bit quantization has become an important topic in massive MIMO systems, as it offers low cost and low complexity in the implementation. Techniques to achieve high performance in spite of the coarse quantizers have recently been advanced. In the context of array processing and direction-of-arrival (DOA) estimation also, one bit quantizers have been studied in the past, although not as extensively. This paper shows that sparse arrays such as nested and coprime arrays are more robust to the deleterious effects of one-bit quantization, compared to uniform linear arrays (ULAs);in fact, sparse arrays with one-bit quantizers are often found to be as good as ULAs with unquantized data. nested and coprime arrays without quanitzers are known to be able to resolve more DOAs than the number of sensors, when sources are uncorrelated. It will be demonstrated that this continues to be true even with one-bit quantization.
Nesting and stemming (infinite successive singling) of arrays of nestings and stemmings result in forms. Forms of 0th-, 1st-, 2nd-, or 3rd-order, array-theoretic, totally defined functions are again such functions, ca...
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ISBN:
(纸本)9780897916127
Nesting and stemming (infinite successive singling) of arrays of nestings and stemmings result in forms. Forms of 0th-, 1st-, 2nd-, or 3rd-order, array-theoretic, totally defined functions are again such functions, called, respectively, figures, changes, rigs, and arms. One arms a rig before rigging a change before changing a figure. Part I lays the foundation for a new approach to a theory of arrays. This Part considers the analogy between array-theoretic and Euclidean figures, analyzes form separately from substance, introduces Nth-order functions, presents the beginnings of a syntax for the theory, and constructs a formal system to deduce the first few consequences of the first two primitive operations.
Spectral Doppler ultrasound imaging allows quantification of blood flow by estimating the velocity distribution of the blood within a range gate on a single image line. In applications, it is desirable to have both br...
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ISBN:
(纸本)9781509011735
Spectral Doppler ultrasound imaging allows quantification of blood flow by estimating the velocity distribution of the blood within a range gate on a single image line. In applications, it is desirable to have both brightness mode (B-mode) at high frame rate, to allow the medical doctor to visualize and follow vessel movement, as well as Doppler mode with high spectral resolution of the velocity distribution, so that changes in blood flow can be tracked. In this paper, we propose a slow-time sparse emission pattern of the blood Doppler signal which significantly reduces the number of transmissions sent. For the proposed sampling scheme, we derive the minimal number of Doppler emissions allowing reconstruction of the signal's power spectrum and provide power spectrum recovery techniques that achieve this minimal rate. Using realistic Field II simulations, we show that accurate estimation of blood velocity spectrum can be performed from only 12% of the transmissions required in conventional scanning. Thus, several vessel regions may be investigated while keeping a high frame rate of the B-mode images.
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