Institution
Xidian University
Education•Xi'an, China•
About: Xidian University is a education organization based out in Xi'an, China. It is known for research contribution in the topics: Antenna (radio) & Synthetic aperture radar. The organization has 32099 authors who have published 38961 publications receiving 431820 citations. The organization is also known as: University of Electronic Science and Technology at Xi'an & Xīān Diànzǐ Kējì Dàxué.
Papers published on a yearly basis
Papers
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TL;DR: The AFF scheme is named and it is shown that with this scheme, the eavesdropper will face a noncoherent Ricean fading single-input-multiple-output channel and the closed-form secrecy rate is difficult to obtain, but an exact expression is derived for the single-antenna-eavesdropper case and a lower bound for the multiantenna-Eaves dropper case, both of which can be numerically calculated conveniently.
Abstract: The artificial noise (AN) scheme is an efficient strategy for enhancing the secrecy rate of a multiple-input–single-output channel in the presence of a passive eavesdropper, whose channel state information is unavailable. Recently, a randomized beamforming scheme has been proposed for deteriorating the eavesdropper's bit-error-rate performance via corrupting its receiving signal by time-varying multiplicative noise. However, the secrecy rate of such a scheme has not been well addressed yet. In this paper, we name it the artificial fast fading (AFF) scheme and provide a comprehensive secrecy rate analysis for it. We show that with this scheme, the eavesdropper will face a noncoherent Ricean fading single-input–multiple-output channel. Although the closed-form secrecy rate is difficult to obtain, we derive an exact expression for the single-antenna-eavesdropper case and a lower bound for the multiantenna-eavesdropper case, both of which can be numerically calculated conveniently. Furthermore, we compare the AFF scheme with the AN scheme and show that their respective superiorities to each other depend on the number of antennas that the transmitter and the eavesdropper possessed, i.e., when the eavesdropper has more antennas than the transmitter does, the AFF scheme achieves a larger secrecy rate; otherwise, the AN scheme outperforms. Motivated by this observation, we propose a hybrid AN-AFF scheme and investigate the power allocation problem, which achieves better secrecy performance further.
135 citations
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TL;DR: A new piezoelectric nanogenerator with a three-dimensional intercalation electrode is developed to reach 290 μA cm −2 by creating and utilizing many boundary interfaces, which contributes to an increased current density.
Abstract: The low output current density of piezoelectric nanogenerators (PENGs) severely restricts their application for ambient mechanical energy harvest. This has been a key challenge in the development of PENG. Here, to conquer this, based on a piezoelectric material with high piezoelectric coefficient (Sm-PMN-PT), a new design of PENG with a three-dimensional intercalation electrode (IENG) is proposed. By creating many boundary interfaces inside the piezoelectric material, the total amount of surface polarization charges increased, which contributes to an increased current density. The IENG can output a maximum peak short-circuit current of 320 μA, and the corresponding current density 290 μA cm−2 is 1.93 and 1.61 times the record values of PENG and triboelectric nanogenerator (TENG), respectively. It can also charge a 1 μF capacitor from 0 V to 8 V in 21 cycles, and the equivalent surface charge density 1690 μC m−2 is 1.35 times the record value of TENG. Increasing the output current density is the key challenge for nanogenerators. Here, a new piezoelectric nanogenerator with a three-dimensional intercalation electrode is developed to reach 290 μA cm−2 by creating and utilizing many boundary interfaces.
135 citations
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TL;DR: In this paper, a broadband dual-polarized base station antenna with sturdy construction is presented, which mainly contains four parts: main radiator, feeding baluns, bedframe, and reflector.
Abstract: A broadband dual-polarized base station antenna with sturdy construction is presented in this letter. The antenna mainly contains four parts: main radiator, feeding baluns, bedframe, and reflector. First, two orthogonal dipoles are etched on a substrate as main radiator forming dual polarization. Two baluns are then introduced to excite the printed dipoles. Each balun has four bumps on the edges for electrical connection and fixation. The bedframe is designed to facilitate the installation, and the reflector is finally used to gain unidirectional radiation. Measured results show that the antenna has a 48% impedance bandwidth with reflection coefficient less than –15 dB and port isolation more than 22 dB. A four-element antenna array with 6° ± 2° electrical down tilt is also investigated for wideband base station application. The antenna and its array have the advantages of sturdy construction, high machining accuracy, ease of integration, and low cost. They can be used for broadband base station in the next-generation wireless communication system.
134 citations
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TL;DR: A novel ABC method called EABC is proposed, which significantly improves the performance of ABC, offering faster global convergence, higher solution quality, and stronger robustness when compared with the other algorithms.
134 citations
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TL;DR: An iterated algorithm for model selection is proposed in this paper, which can automatically give the optimal aspect-frames boundaries and determine the optimal number of factors in each aspect-frame and the proposed adaptive partition approach can further improve the recognition performance with higher recognition efficiency.
Abstract: Statistical modeling for radar high-resolution range profile (HRRP) is a challenging task in radar HRRP statistical recognition. Theoretical analysis and experimental results show that elements in an HRRP sample are statistically correlated and non-Gaussian distributed. First, this paper introduces three joint-Gaussian models, i.e., subspace approximation model, probability principal components analysis (PPCA) model and factor analysis (FA) model, into radar HRRP statistical recognition. Due to the experimental results, we can have the conclusion that the jointly non-Gaussian distributed HRRP samples approximately follow the joint-Gaussian distribution described by FA model. Therefore, we can apply FA model to radar HRRP statistical recognition rather than a joint-Gaussian mixture model, e.g., PPCA mixture model or FA mixture model, which is a more accurate choice for modeling non-Gaussian distributed correlations in multidimensional data but with high learning complexity and large computation burden, and the difficulty in the statistical modeling for HRRP samples is largely reduced. Second, this paper concerns model selection of FA model in radar HRRP statistical recognition, in which there are two issues, i.e., the partition of target-aspect frames and the determination of the number of factors in each frame. Based on the Akaike information criterion (AIC) and the Bayes' information criterion (BIC), an iterated algorithm for model selection is proposed in this paper, which can automatically give the optimal aspect-frame boundaries and determine the optimal number of factors in each aspect-frame. The recognition experiments based on measured data show that the proposed adaptive partition approach can further improve the recognition performance with higher recognition efficiency.
134 citations
Authors
Showing all 32362 results
Name | H-index | Papers | Citations |
---|---|---|---|
Zhong Lin Wang | 245 | 2529 | 259003 |
Jie Zhang | 178 | 4857 | 221720 |
Bin Wang | 126 | 2226 | 74364 |
Huijun Gao | 121 | 685 | 44399 |
Hong Wang | 110 | 1633 | 51811 |
Jian Zhang | 107 | 3064 | 69715 |
Guozhong Cao | 104 | 694 | 41625 |
Lajos Hanzo | 101 | 2040 | 54380 |
Witold Pedrycz | 101 | 1766 | 58203 |
Lei Liu | 98 | 2041 | 51163 |
Qi Tian | 96 | 1030 | 41010 |
Wei Liu | 96 | 1538 | 42459 |
MengChu Zhou | 96 | 1124 | 36969 |
Chunying Chen | 94 | 508 | 30110 |
Daniel W. C. Ho | 85 | 360 | 21429 |