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  1. Article: Wintertime Variability of Currents in the Southwestern Taiwan Strait

    Wang, Li / Pawlowicz, Rich / Wu, Xiongbin / Yue, Xianchang

    Journal of geophysical research. 2021 May, v. 126, no. 5

    2021  

    Abstract: A 57‐days record of surface currents observed from high‐frequency radars on the Chinese coast, along with wind records, are analyzed to investigate wintertime variability of surface currents in the southwestern Taiwan Strait. The M₂ tide dominates tidal ... ...

    Abstract A 57‐days record of surface currents observed from high‐frequency radars on the Chinese coast, along with wind records, are analyzed to investigate wintertime variability of surface currents in the southwestern Taiwan Strait. The M₂ tide dominates tidal variability, and the semimajor axes of semidiurnal tidal current ellipses coincide well with bathymetry contours suggesting interactions with a propagating tidal wave. However, phase progressions suggest that this wave undergoes an angular reflection near the Taiwan Bank (TWB). Diurnal currents are less correlated to bathymetry perhaps because many different diurnal tide waves interact here. Surface currents are strongly related to winds at subtidal frequencies. Subtidal along‐strait currents have a correlation of 0.8 with along‐strait winds. However, three different spatial current patterns appear depending on the strength of along‐strait winter monsoon. Downwind currents occur when northeasterly wind is stronger than 10 m s⁻¹. For medium winds, a gradual change in the pattern of currents is observed, including an offshore flow north of the TWB. In low winds conditions, when winds can be either northeasterly or (sometimes) southwesterly, the eastward flow along the northern edge of the TWB increases to 20 cm s⁻¹; elsewhere flow is to the northeast. This forms a counter‐wind current when winds are from the northeast. By investigating the momentum balance, we find that in along‐strait direction wind stress and pressure gradient are important over the TWB, and a geostrophic balance dominates north of bank. In the cross‐strait direction, momentum is dominated by a geostrophic balance over the entire region.
    Keywords coasts ; geophysics ; momentum ; monsoon season ; research ; tides ; wind ; wind stress ; winter ; Taiwan
    Language English
    Dates of publication 2021-05
    Publishing place John Wiley & Sons, Ltd
    Document type Article
    Note JOURNAL ARTICLE
    ZDB-ID 161667-5
    ISSN 2169-9291 ; 2169-9275 ; 0148-0227 ; 0196-2256
    ISSN (online) 2169-9291
    ISSN 2169-9275 ; 0148-0227 ; 0196-2256
    DOI 10.1029/2020JC016586
    Database NAL-Catalogue (AGRICOLA)

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  2. Article ; Online: FAR-Net: Feature-Wise Attention-Based Relation Network for Multilabel Jujube Defect Classification.

    Xu, Xiaohang / Zheng, Hong / You, Changhui / Guo, Zhongyuan / Wu, Xiongbin

    Sensors (Basel, Switzerland)

    2021  Volume 21, Issue 2

    Abstract: In production, due to natural conditions or process peculiarities, a single product often may exhibit more than one type of defect. The accurate identification of all defects has an important guiding significance and practical value to improve the ... ...

    Abstract In production, due to natural conditions or process peculiarities, a single product often may exhibit more than one type of defect. The accurate identification of all defects has an important guiding significance and practical value to improve the planting and production processes. Concerning the surface defect classification task, convolutional neural networks can be implemented as a powerful instrument. However, a typical convolutional neural network tends to consider an image as an inseparable entity and a single instance when extracting features; moreover, it may overlook semantic correlations between different labels. To address these limitations, in the present paper, we proposed a feature-wise attention-based relation network (FAR-Net) for multilabel jujube defect classification. The network included four different modules designed for (1) image feature extraction, (2) label-wise feature aggregation, (3) feature activation and deactivation, and (4) correlation learning among labels. To evaluate the proposed method, a unique multilabel jujube defect dataset was constructed as a benchmark for the multilabel classification task of the jujube defect images. The results of experiments show that owing to the relation learning mechanism, the average precision of the three main composite defects in the dataset increases by 5.77%, 4.07%, and 3.50%, respectively, compared to the backbone of our network, namely Inception v3, which indicated that the proposed FAR-Net effectively facilitated the learning of correlation between labels and eventually, improved the multilabel classification accuracy.
    Language English
    Publishing date 2021-01-08
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2052857-7
    ISSN 1424-8220 ; 1424-8220
    ISSN (online) 1424-8220
    ISSN 1424-8220
    DOI 10.3390/s21020392
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Ultra-wideband linear-to-circular polarizer realized by bi-layer metasurfaces.

    Gao, Xi / Li, Kexin / Wu, Xiongbin / Xue, Chunhua / Wang, Guofu / Xie, Xianming / Qin, Mimi

    Optics express

    2022  Volume 30, Issue 11, Page(s) 18392–18401

    Abstract: We propose a bi-layer transmissive metasurface to obtain linear-to-circular polarization conversion in a wideband. The unit cell of each metasurface layer, which has identical configuration, consists of a Jerusalem-cross-like resonator and a metal strip. ...

    Abstract We propose a bi-layer transmissive metasurface to obtain linear-to-circular polarization conversion in a wideband. The unit cell of each metasurface layer, which has identical configuration, consists of a Jerusalem-cross-like resonator and a metal strip. A universal equivalent circuit model is employed to guide the design of the polarizer. By analyzing the circuit parameters of the equivalent circuit, four metal strips are symmetrically inserted in each unit cell to broaden the bandwidth of linear-to-circular polarization conversion. Numerical and experimental results show that the polarizer can convert a linearly polarized wave into a circularly polarized wave in a wideband from 6.1 GHz to 12.6 GHz. Compared to the reported designs, the proposed polarization converter has advantages of ultrathin thickness and ultrawideband, and hence can be used in many applications, such as antennas and remote sensors.
    Language English
    Publishing date 2022-10-12
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1491859-6
    ISSN 1094-4087 ; 1094-4087
    ISSN (online) 1094-4087
    ISSN 1094-4087
    DOI 10.1364/OE.460685
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Research on a Simulation Model of a Skywave Over-the-Horizon Radar Sea Echo Spectrum

    Feng, Mengyan / Fang, Hanxian / Ai, Weihua / Wu, Xiongbin / Yue, Xianchang / Zhang, Lan / Guo, Chaogang / Zhou, Qing / Li, Xiaoyan

    Remote Sensing. 2022 Mar. 18, v. 14, no. 6

    2022  

    Abstract: The capability of a skywave over-the-horizon radar (SWR) to achieve the continuous observation of a wide range of ocean dynamics parameters via a single ionospheric reflection has been demonstrated by many scholars. In order to expand the method of SWR ... ...

    Abstract The capability of a skywave over-the-horizon radar (SWR) to achieve the continuous observation of a wide range of ocean dynamics parameters via a single ionospheric reflection has been demonstrated by many scholars. In order to expand the method of SWR detection of ocean dynamics parameters, a simulation model of an SWR sea echo spectrum based on the Barrick sea surface scattering cross-section model (Barrick model) and 3D ray-tracing method, suitable for a narrow-beam, frequency-modulated continuous-wave radar system (FMCW), was established. Based on this model, we simulated ideal and contaminated SWR sea echo spectra, respectively with the 3D electron density data output by the International Reference Ionosphere (IRI) model. Then, we further analyzed the effects of the grazing incidence angle, scattering angle, scattering azimuth angle and fetch length on the sea surface scattering cross-sections, the retrieval precision of the sea surface wind direction, and the root-mean-square (RMS) wave height, using the simulation data calculated by the Barrick model. The results show that these angles and fetch length cause a small expansion and contraction of the scattering cross-section, and have no influence on the retrieval precision of the sea surface wind direction, but will affect the retrieval precision of the RMS wave height; the influence of the grazing incidence angle and scattering angle is ~2.5 times that of the scattering azimuth angle. The ideal SWR sea echo spectrum has small broadening, but the ionosphere phase contamination will cause serious broadening and shifting of the SWR sea echo spectrum, and the higher order nonlinear term has greater contamination.
    Keywords angle of incidence ; radar ; simulation models ; wind direction
    Language English
    Dates of publication 2022-0318
    Publishing place Multidisciplinary Digital Publishing Institute
    Document type Article
    ZDB-ID 2513863-7
    ISSN 2072-4292
    ISSN 2072-4292
    DOI 10.3390/rs14061461
    Database NAL-Catalogue (AGRICOLA)

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  5. Article ; Online: Digital Forensics of Scanned QR Code Images for Printer Source Identification Using Bottleneck Residual Block.

    Guo, Zhongyuan / Zheng, Hong / You, Changhui / Xu, Xiaohang / Wu, Xiongbin / Zheng, Zhaohui / Ju, Jianping

    Sensors (Basel, Switzerland)

    2020  Volume 20, Issue 21

    Abstract: With the rapid development of information technology and the widespread use of the Internet, QR codes are widely used in all walks of life and have a profound impact on people's work and life. However, the QR code itself is likely to be printed and ... ...

    Abstract With the rapid development of information technology and the widespread use of the Internet, QR codes are widely used in all walks of life and have a profound impact on people's work and life. However, the QR code itself is likely to be printed and forged, which will cause serious economic losses and criminal offenses. Therefore, it is of great significance to identify the printer source of QR code. A method of printer source identification for scanned QR Code image blocks based on convolutional neural network (PSINet) is proposed, which innovatively introduces a bottleneck residual block (BRB). We give a detailed theoretical discussion and experimental analysis of PSINet in terms of network input, the first convolution layer design based on residual structure, and the overall architecture of the proposed convolution neural network (CNN). Experimental results show that the proposed PSINet in this paper can obtain extremely excellent printer source identification performance, the accuracy of printer source identification of QR code on eight printers can reach 99.82%, which is not only better than LeNet and AlexNet widely used in the field of digital image forensics, but also exceeds state-of-the-art deep learning methods in the field of printer source identification.
    Language English
    Publishing date 2020-11-05
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2052857-7
    ISSN 1424-8220 ; 1424-8220
    ISSN (online) 1424-8220
    ISSN 1424-8220
    DOI 10.3390/s20216305
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article: Fractional Fourier Transform-Based Radio Frequency Interference Suppression for High-Frequency Surface Wave Radar

    Zhou, Qing / Zheng, Hong / Wu, Xiongbin / Yue, Xianchang / Chen, Zhangyou / Wang, Qinxiong

    Remote Sensing. 2019 Dec. 24, v. 12, no. 1

    2019  

    Abstract: High-frequency surface wave radar (HF SWR) plays an important role in marine stereoscopic monitoring system. Nevertheless, the congestion of external radio frequency interference (RFI) in HF band degrades its performance seriously. In this article, two ... ...

    Abstract High-frequency surface wave radar (HF SWR) plays an important role in marine stereoscopic monitoring system. Nevertheless, the congestion of external radio frequency interference (RFI) in HF band degrades its performance seriously. In this article, two novel fractional Fourier transform (FRFT)-based RFI suppression approaches are proposed. One is based on the orthogonal projection of sequences from fractional Fourier domain, and the other is based on singular value decomposition (SVD) of Hankel matrix of sequences from fractional inverse-Fourier domain. Simulation and experimental data collected by HF SWR from Wuhan University were used to test the effectiveness as well as the application condition of the proposed RFI suppression algorithms. The FRFT-based orthogonal projection algorithm is practicable for suppressing stationary RFI with unvaried carrier frequency, while the FRFT-based SVD algorithm is applicable equally for mitigating nonstationary RFI with time-varying carrier frequency or occasional duration time. The processing results may provide useful guidelines for interference suppression of HF SWR, and inspiring the further application of the FRFT-based methods for signal processing.
    Keywords algorithms ; data collection ; guidelines ; monitoring ; radar ; radio waves ; remote sensing
    Language English
    Dates of publication 2019-1224
    Publishing place Multidisciplinary Digital Publishing Institute
    Document type Article
    ZDB-ID 2513863-7
    ISSN 2072-4292
    ISSN 2072-4292
    DOI 10.3390/rs12010075
    Database NAL-Catalogue (AGRICOLA)

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  7. Book ; Online: Long-term lidar observations of the gravity wave activity near the mesopause at Arecibo

    Yue, Xianchang / Friedman, Jonathan S. / Zhou, Qihou / Wu, Xiongbin / Lautenbach, Jens

    eISSN: 1680-7324

    2019  

    Abstract: Using 11-year-long K Doppler lidar observations of temperature profiles in the mesosphere and lower thermosphere (MLT) between 85 and 100 km, conducted at the Arecibo Observatory, Puerto Rico (18.35 ∘ N, 66.75 ∘ W), seasonal variations of mean ... ...

    Abstract Using 11-year-long K Doppler lidar observations of temperature profiles in the mesosphere and lower thermosphere (MLT) between 85 and 100 km, conducted at the Arecibo Observatory, Puerto Rico (18.35 ∘ N, 66.75 ∘ W), seasonal variations of mean temperature, the squared Brunt–Väisälä frequency, N 2 , and the gravity wave potential energy (GWPE) are estimated in a composite year. The following unique features are obtained. (1) The mean temperature structure shows similar characteristics to an earlier report based on a smaller dataset. (2) Temperature inversion layers (TILs) occur at 94–96 km in spring, at ∼92 km in summer, and at ∼91 km in early autumn. (3) The first complete range-resolved climatology of GWPE derived from temperature data in the tropical MLT exhibits an altitude-dependent combination of annual oscillation (AO) and semiannual oscillation (SAO). The maximum occurs in spring and the minimum in summer, and a second maximum is in autumn and a second minimum in winter. (4) The GWPE per unit volume reduces below ∼97 km altitude in all seasons. The reduction of GWPE is significant at and below the TILs but becomes faint above; this provides strong support for the mechanism that the formation of upper mesospheric TILs is mainly due to the reduction of GWPE. The climatology of GWPE shows an indeed pronounced altitudinal and temporal correlation with the wind field in the tropical mesopause region published in the literature. This suggests the GW activity in the tropical mesopause region should be manifested mainly by the filtering effect of the critical level of the local background wind and the energy conversion due to local dynamical instability.
    Subject code 333
    Language English
    Publishing date 2019-03-12
    Publishing country de
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  8. Article ; Online: 'Shi Han Quan' natural soda water prevents development of gout.

    Zhao, Qingsong / Wang, Lipei / Wu, Xiongbin / Liu, Tingting / Xu, Jinmei / Li, Ming / Li, Bo / Guo, Min / Cheng, Zhifeng

    International journal of rheumatic diseases

    2017  Volume 21, Issue 1, Page(s) 330–337

    Abstract: Purpose: This study aimed to explore the regulatory mechanism of the natural soda Shi Han Quan (SHQ) in the development of gout.: Methods: Human umbilical vein endothelial cells (HUVECs) were stimulated with monosodium urate (MSU) for 24 h to induce ... ...

    Abstract Purpose: This study aimed to explore the regulatory mechanism of the natural soda Shi Han Quan (SHQ) in the development of gout.
    Methods: Human umbilical vein endothelial cells (HUVECs) were stimulated with monosodium urate (MSU) for 24 h to induce acute gouty inflammation in vitro. HUVECs were divided into four groups: ddH
    Results: The viability of HUVECs was significantly decreased with increasing transfection concentrations of MSU, and MSU treatment resulted in a significant increase of the concentration and expression of ICAM-1. In addition, SHQ improved the MSU-induced decrease in cell viability and alleviated MSU-mediated increase in ICAM-1 levels. Moreover, SHQ decreased MSU-induced release of IL-1β and IL-6. After HUVECs were incubated with the culture supernatant of THP-1 cells that had been treated with PMA, MSU and SHQ for 24 h, SHQ also markedly alleviated the effects of MSU, such as by increasing cell viability and decreasing ICAM-1 levels.
    Conclusions: Drinking natural soda water may have a significant role in preventing gouty inflammation.
    MeSH term(s) Carbonated Water ; Cell Survival/drug effects ; Culture Media, Conditioned/metabolism ; Dose-Response Relationship, Drug ; Gout/chemically induced ; Gout/metabolism ; Gout/pathology ; Gout/prevention & control ; Gout Suppressants/pharmacology ; Human Umbilical Vein Endothelial Cells/drug effects ; Human Umbilical Vein Endothelial Cells/metabolism ; Human Umbilical Vein Endothelial Cells/pathology ; Humans ; Intercellular Adhesion Molecule-1/genetics ; Intercellular Adhesion Molecule-1/metabolism ; Interleukin-1beta/genetics ; Interleukin-1beta/metabolism ; Interleukin-6/genetics ; Interleukin-6/metabolism ; THP-1 Cells ; Uric Acid/toxicity
    Chemical Substances Carbonated Water ; Culture Media, Conditioned ; Gout Suppressants ; ICAM1 protein, human ; IL1B protein, human ; IL6 protein, human ; Interleukin-1beta ; Interleukin-6 ; Intercellular Adhesion Molecule-1 (126547-89-5) ; Uric Acid (268B43MJ25)
    Language English
    Publishing date 2017-10-30
    Publishing country England
    Document type Journal Article
    ZDB-ID 2426924-4
    ISSN 1756-185X ; 1756-1841
    ISSN (online) 1756-185X
    ISSN 1756-1841
    DOI 10.1111/1756-185X.13181
    Database MEDical Literature Analysis and Retrieval System OnLINE

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