Article
Engineering, Electrical & Electronic
Zixiang Yang, Qing Shen, Wei Liu, Yonina C. C. Eldar, Wei Cui
Summary: This paper presents a novel approach to designing structures based on the high-order difference co-array concept, which provides a large number of degrees of freedom and meets multiple optimization criteria. By recursively using a simple generator, a fractal array based on the 2qth-order difference co-array (2qth-O-Fractal) is formed, inheriting multiple desirable properties from the generator under certain conditions.
IEEE TRANSACTIONS ON SIGNAL PROCESSING
(2023)
Article
Statistics & Probability
Ciprian A. Tudor, Nakahiro Yoshida
Summary: By combining the Malliavin calculus with Fourier techniques, this study develops a high-order asymptotic expansion theory for general Wiener functionals. The method allows for an expansion of the characteristic function and local density of a Wiener functional up to an arbitrary order, and the expansion is distributional. Unlike previous research, this method does not require non-degeneracy conditions or the Markovian property.
STOCHASTIC PROCESSES AND THEIR APPLICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Zixiang Yang, Qing Shen, Wei Liu, Yonina C. C. Eldar, Wei Cui
Summary: In this work, fractal arrays were proposed for exploiting the 2qth-order difference co-array. The robustness and mutual coupling leakage of the 2qth-O-Fractal framework were analyzed. The results showed that the robustness of 2qth-O-Fractal could be improved by designing a robust generator or increasing the fractal order. The mutual coupling leakage of 2qth-O-Fractal was also upper bounded by that of its generator array. Simulation results demonstrated the superior performance of the proposed 2qth-O-Fractal over existing structures.
IEEE TRANSACTIONS ON SIGNAL PROCESSING
(2023)
Article
Engineering, Electrical & Electronic
Zheng Li, Xiaofei Zhang
Summary: This paper addresses the 2-D direction of arrival (DOA) estimation problem for L-shaped monostatic MIMO radar with two-level nested linear array (NLA). A more degrees of freedom (DOFs) ENLs MIMO radar is proposed to outperform traditional NLs MIMO radar. The search-free iterative Taylor expansion (SF-ITE) algorithm is introduced to enhance DOA estimation accuracy.
DIGITAL SIGNAL PROCESSING
(2021)
Article
Engineering, Mechanical
Yunlai Zhou, Youjie Cao, Ning Wang, Magd Abdel Wahab
Summary: In this paper, a numerical simulation of electromagnetic ultrasonic nondestructive testing is carried out for crack detection on L-shaped aluminum plates. The field distribution characteristics and the influence of the parameters of the electromagnetic ultrasonic transducer on crack detection are analyzed. The parameters of the transducer are optimized by orthogonal experiments, resulting in a significant improvement in the amplitude of the crack echo signal and thus enhancing the crack detection.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Mathematics, Applied
Wei Lin, Jin E. Zhang
Summary: This paper discusses the application of truncated expansions of the Gram-Charlier series in approximating probability density functions. It proposes a method to implement valid regions of higher cumulants using a semi-definite algorithm. The results show that higher-order expansions can broaden the valid regions.
JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS
(2022)
Article
Engineering, Electrical & Electronic
Umesh Sharma, Monika Agrawal
Summary: This paper proposes a processing method based on second-order circular cumulants and virtual array to enhance the resolvability of a single acoustic vector sensor. The paper also derives the theoretical upper bound on the maximum number of identifiable two-dimensional direction of arrivals for statistically independent, non-Gaussian sources.
DIGITAL SIGNAL PROCESSING
(2022)
Article
Engineering, Electrical & Electronic
Chibuzo Joseph Nnonyelu, Zakayo Ndiku Morris, Chinaza Alice Madukwe
Summary: The study compared the direction finding performance of L-shaped and V-shaped arrays of first-order cardioid microphones, finding that the L-shaped array generally outperforms the V-shaped array in more regions, with higher variance ratios favoring the V-shaped array in certain areas.
IEEE SENSORS JOURNAL
(2021)
Article
Telecommunications
Zhi Zheng, Shilin Mu
Summary: This new approach proposes a method for two-dimensional direction finding using an L-shaped array structured by two nested arrays. By vectorizing covariance matrices of the nested array outputs and using a permutation matrix for pair-matching, it reconstructs the source covariance matrix in the coarray domain, allowing for more sources to be handled. Numerical results demonstrate its advantage over existing algorithms.
IEEE COMMUNICATIONS LETTERS
(2021)
Article
Acoustics
Longyu Jiang, Zhe Zhang, Philippe Roux
Summary: In this paper, a three-dimensional (3D) higher-order raypath separation method is proposed for separating raypaths in a multipath shallow-water environment. The proposed algorithm addresses the challenges of interference and colored noise between raypaths, especially for closely arriving raypaths. Performance tests using simulation data, real data, and ocean shallow-water data demonstrate that the proposed algorithm achieves higher resolution and stronger robustness compared to existing algorithms.
JASA EXPRESS LETTERS
(2022)
Article
Geochemistry & Geophysics
Huaifei Chen, Weijiang Chen, Yu Wang, Kai Bian, Nianwen Xiang, Kejie Li, Zhu Zhang
Summary: This article proposes an improved MUSIC-based lightning mapping algorithm that enhances efficiency and quality by transforming the problem and arranging the array in a nonuniform way. Simulation and observation results verify the performance and advantages of the algorithm.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2022)
Article
Optics
Yang Yan, Jinpeng Yuan, Linjie Zhang, Liantuan Xiao, Suotang Jia, Lirong Wang
Summary: This article describes a Ku-band three-dimensional location system using an L-shaped array of Rydberg atomic receivers, which can accurately locate microwave fields in three-dimensional space. The experimental results show high accuracy and velocity measurement capability of the system.
Article
Engineering, Electrical & Electronic
Nicola Anselmi, Luca Tosi, Paolo Rocca, Giovanni Toso, Andrea Massa
Summary: This study focuses on the design of irregular planar phased arrays with a modular architecture. It utilizes rep-tiles, self-replicating tile shapes, to generate array layouts consisting of tiles with different sizes but equal shapes. The use of deterministic optimization allows for the creation of an optimal tradeoff between complexity, costs, and the desired radiated power pattern while ensuring complete overlay of the array aperture. Results demonstrate the effectiveness of this approach in handling large-size array apertures compared to existing tiling techniques.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Chemistry, Analytical
Bo Du, Weijia Cui, Bin Ba, Haiyun Xu, Wubin Gao
Summary: The degree of freedom (DOF) is an important metric for evaluating sparse array designs in the field of DOA estimation. This paper proposes a novel L-shaped sparse sensor array that achieves higher degrees of freedom by adjusting the physical placement of sensors. The array consists of two sets of TSESAs, which estimate azimuth and elevation angles through 1-D spatial spectrum search. Simulation experiments demonstrate the superior performance of the proposed L-shaped TSESA in 2-D DOA estimation, due to its higher degrees of freedom and array aperture.
Article
Engineering, Electrical & Electronic
Hang Zheng, Zhiguo Shi, Chengwei Zhou, Martin Haardt, Jian Chen
Summary: In this letter, we propose a two-dimensional DOA estimation method based on coupled coarray tensor CPD, which utilizes a shifting coarray concatenation approach to factorize multiple coarray tensors and jointly decompose them to achieve high-accuracy DOA estimation. The proposed method guarantees an increased number of degrees-of-freedom for DOA estimation according to the uniqueness condition analysis on the coupled coarray tensor CPD.
IEEE SIGNAL PROCESSING LETTERS
(2021)
