In array signal processing systems, the direction of arrival (DOA) and polarization of signals based on uniform linear or rectangular sensor arrays are generally obtained by rotational invariance techniques (ESPRIT). However, since the ESPRIT algorithm relies on the rotational invariant structure of the received data, it cannot be applied to electromagnetic vector sensor arrays (EVSAs) featuring uniform circular patterns. To overcome this limitation, a fourth-order cumulant-based ESPRIT algorithm is proposed in this paper, for joint estimation of DOA and polarization based on a uniform circular EVSA. The proposed algorithm utilizes the fourth-order cumulant to obtain a virtual extended array of a uniform circular EVSA, from which the pairs of rotation invariant sub-arrays are obtained. The ESPRIT algorithm and parameter pair matching are then utilized to estimate the DOA and polarization of the incident signals. The closed-form parameter estimation algorithm can effectively reduce the computational complexity of the joint estimation, which has been demonstrated by numerical simulations.
Recent research has considered DNA an inter-esting medium for long-term and ultra compact information storage and a stegomedium for hid-den messages. Artificial components of DNA with encoded information can be added to the genome of living organisms, such as common bacteria. With this approach, a medium for very height densities information storage, water-marks for protection patents of genetically mo- dified organisms (GMOs) and secure public keys for decrypting hidden information in stega- nocryptography, can be obtained. In this paper, we have selected a Bacillus subtilis gene (tatAD) and use the specific properties of silent muta-tions to obtain a biologically innocuous product. An adapted code for the message insertion in this gene is proposed
This paper proposes a novel estimation method, named double scale two dimensional frequency distribution (DSTFD), to estimate the parameters of quadratic frequency modulated (QFM) signals. In the DSTFD, by using a novel parametric instantaneous self-correlation function and the idea of the keystone transform, the QFM signals are transformed into two-dimensional frequency domain, and the QFM signals are detected by searching peaks. To reduce computational cost, a double scale (DS) estimation strategy, which consists of coarse estimation and fine estimation, is proposed. The DS estimation strategy can be implemented by using the Chirp Z-transform and an improved transform named local scaled Fourier transform (LSFT). The LSFT only consists of complex multiplications, fast Fourier transform (FFT), and inverse FFT operations. The implementation, anti-noise performance, and computational cost are analyzed for the proposed method. Through simulations and analyses, the results demonstrate that the DSTFD outperforms other compared algorithms. INDEX TERMS Double scale two dimensional frequency distribution (DSTFD), quadratic frequency modulated (QFM), parameter estimation, parametric instantaneous self-correlation function (PISCF), double scale estimation strategy.
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