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  1. Article ; Online: DRFM-Based Repeater Jamming Reconstruction and Cancellation Method with Accurate Edge Detection

    Bowen Han / Xiaodong Qu / Xiaopeng Yang / Wolin Li / Zhengyan Zhang

    Remote Sensing, Vol 15, Iss 1759, p

    2023  Volume 1759

    Abstract: Digital radio frequency memory (DRFM) based repeater jamming can create false targets, which can lead to a loss of situational awareness, misidentification of targets, and decreased overall performance of the radar system. Traditional jamming suppression ...

    Abstract Digital radio frequency memory (DRFM) based repeater jamming can create false targets, which can lead to a loss of situational awareness, misidentification of targets, and decreased overall performance of the radar system. Traditional jamming suppression methods do not give due importance to the accurate estimation of the jamming edge, resulting in jamming residual and poor anti-jamming performance. To tackle this issue, this paper explores the reason and impact of inaccurate jamming edge estimation and proposes a DRFM-based repeater jamming reconstruction and cancellation method with accurate edge detection. In the proposed method, firstly, multiple jamming parameters are obtained by computing the short-time fractional Fourier transformation ( STFRFT ) spectrogram of the received signal. To avoid jamming residue, the proposed method estimates the accurate jamming edges by the joint use of the difference of box (DOB) filters and time domain deconvolution (TDDC) curves. Numerical simulations and experiments are conducted to evaluate the algorithm’s effectiveness in countering smeared spectrum (SMSP) and interrupted sampling repeater jamming (ISRJ). The results demonstrate its superior jamming reconstruction and suppression performance than other methods.
    Keywords digital radio frequency modulation ; repeater jamming ; jamming reconstruction and cancellation ; accurate edge detection ; Science ; Q
    Subject code 518
    Language English
    Publishing date 2023-03-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Editorial

    Naicheng Wu / Min Zhang / Xiaodong Qu / Francisco Martinez-Capel

    Frontiers in Ecology and Evolution, Vol

    Biodiversity conservation and ecological function restoration in freshwater ecosystems

    2023  Volume 11

    Keywords anthropogenic factors ; biodiversity ; ecological function ; freshwater ; traits ; Evolution ; QH359-425 ; Ecology ; QH540-549.5
    Language English
    Publishing date 2023-02-01T00:00:00Z
    Publisher Frontiers Media S.A.
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: DRFM Repeater Jamming Suppression Method Based on Joint Range-Angle Sparse Recovery and Beamforming for Distributed Array Radar

    Bowen Han / Xiaodong Qu / Xiaopeng Yang / Zhengyan Zhang / Wolin Li

    Remote Sensing, Vol 15, Iss 3449, p

    2023  Volume 3449

    Abstract: Distributed array radar achieves high angular resolution and measurement accuracy, which could provide a solution to suppress digital radio frequency memory (DRFM) repeater jamming. However, owing to the large aperture of a distributed radar, the far- ... ...

    Abstract Distributed array radar achieves high angular resolution and measurement accuracy, which could provide a solution to suppress digital radio frequency memory (DRFM) repeater jamming. However, owing to the large aperture of a distributed radar, the far-field plane wave assumption is no longer satisfied. Consequently, traditional adaptive beamforming methods cannot work effectively due to mismatched steering vectors. To address this issue, a DRFM repeater jamming suppression method based on joint range-angle sparse recovery and beamforming for distributed array radar is proposed in this paper. First, the steering vectors of the distributed array are reconstructed according to the spherical wave model under near-field conditions. Then, a joint range-angle sparse dictionary is generated using reconstructed steering vectors, and the range-angle position of jamming is estimated using the weighted L1-norm singular value decomposition (W-L1-SVD) algorithm. Finally, beamforming with joint range-angle nulling is implemented based on the linear constrained minimum variance (LCMV) algorithm for jamming suppression. The performance and effectiveness of proposed method is validated by simulations and experiments on an actual ground-based distributed array radar system.
    Keywords DRFM repeater jamming ; sparse recovery ; spherical wave model ; distributed array radar ; Science ; Q
    Language English
    Publishing date 2023-07-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Impact of land use on macroinvertebrates from a multiscale perspective

    Kai Ma / Haiping Zhang / Min Zhang / Xiaodong Qu / Nacheng Wu

    Frontiers in Ecology and Evolution, Vol

    enhancing structural equation models with inverse distance-weighted metrics

    2023  Volume 11

    Abstract: Effective riverine ecosystem management and restoration are predicated upon comprehending the relationship between land use patterns, the aquatic environment, and macroinvertebrates. However, the processes by which land use affects riverine ecosystems ... ...

    Abstract Effective riverine ecosystem management and restoration are predicated upon comprehending the relationship between land use patterns, the aquatic environment, and macroinvertebrates. However, the processes by which land use affects riverine ecosystems are exceedingly complex, influenced by factors across varying special scales. To explore these multi-scale relationships, we centered our study on the Taizi River Basin (TRB) in northeastern China, encompassing data on land use, macroinvertebrates, physical habitats, and water quality. We employed a synergy of correlation analysis, multiple stepwise regression, and redundant analysis techniques to discern these relationships at diverse spatial extents. This approach led to the development of 24 structural equation models (SEMs) that delineate the pathways bridging land use patterns to various biological indices. Remarkably, the interpretive capacity of SEM-Benthic Index of Biotic Integrity (SEM-BIBI), SEM-Shannon Wiener index (SEM-H’), and SEM-Average Score Per Taxon (SEM-ASPT) models was 76%, 70%, and 66% respectively. Within the TRB, the primary pathway from land use pattern to biological index consisted of: land use (predominantly rural and agricultural) feeding into physical habitat (habitat complexity, combined characteristic of speed and depth), which in turn affected benthic indicators. A secondary pathway charts a course from land use, through water quality (electrical conductivity and total dissolved solids) and culminating in benthic variations. Furthermore, our findings indicated that inverse-distance-weighted (IDW) metrics, specifically the IDW distance based on flow length to the stream outlet and the nearest stream (iFLO_m and iFLS_m, respectively) could provide more accurate interpretations of the river’s ecological health status. Given the effects of rural areas and agriculture on macroinvertebrates, we recommend establishing 100-m wide riparian buffers. The optimal buffer range should be determined by evaluating various biological needs and ...
    Keywords land use pattern ; macroinvertebrate ; structural equation models ; IDW ; multiple pathways ; Evolution ; QH359-425 ; Ecology ; QH540-549.5
    Subject code 910
    Language English
    Publishing date 2023-12-01T00:00:00Z
    Publisher Frontiers Media S.A.
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article ; Online: Method of Eliminating Helicopter Vibration Interference Magnetic Field with a Pair of Magnetometers

    Yongqiang Feng / Yaoxin Zheng / Luzhao Chen / Xiaodong Qu / Guangyou Fang

    Applied Sciences, Vol 12, Iss 2065, p

    2022  Volume 2065

    Abstract: The low-frequency electromagnetic fields and magnetic anomalies generated by ships and other underwater platforms are widely recognized as important features for ocean target detection. Low-frequency magnetic fields and anomalies are typically measured ... ...

    Abstract The low-frequency electromagnetic fields and magnetic anomalies generated by ships and other underwater platforms are widely recognized as important features for ocean target detection. Low-frequency magnetic fields and anomalies are typically measured by optically pumped magnetometers installed on aircraft. However, the interference that is generated by the aircraft platform may significantly affect the detection performance. The traditional aeromagnetic compensation model has a good effect on eliminating the interference magnetic field that is caused by the carrier attitude variation. Usually, the magnetometer is fixed at the top of a long probe on the aircraft to avoid the influence from the main body in the aircraft. However, the probe is sensitive to external vibrations, and vibration-induced magnetic interference can occur in the measurements. The magnetometer is especially easily affected by the interference magnetic field, including the vibration frequency and harmonic frequency of the probe, in a moving platform, such as a helicopter. These interference fields usually have independent frequency characteristics that can be eliminated by compensation methods. In this paper, we propose a method based on the improved coherent noise suppression method with a pair of magnetometers to eliminate the effects from these magnetic field disturbances and improve the detection performance of the measurement system. The results of the flight experiment show that the method can effectively eliminate low-frequency vibration interference and improve the detection ability of weak signals from targets.
    Keywords vibration interference field ; aeromagnetic compensation ; coherent noise suppression method ; Technology ; T ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Biology (General) ; QH301-705.5 ; Physics ; QC1-999 ; Chemistry ; QD1-999
    Subject code 621
    Language English
    Publishing date 2022-02-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: Personalized Federated Learning for Heterogeneous Residential Load Forecasting

    Xiaodong Qu / Chengcheng Guan / Gang Xie / Zhiyi Tian / Keshav Sood / Chaoli Sun / Lei Cui

    Big Data Mining and Analytics, Vol 6, Iss 4, Pp 421-

    2023  Volume 432

    Abstract: Accurate load forecasting is critical for electricity production, transmission, and maintenance. Deep learning (DL) model has replaced other classical models as the most popular prediction models. However, the deep prediction model requires users to ... ...

    Abstract Accurate load forecasting is critical for electricity production, transmission, and maintenance. Deep learning (DL) model has replaced other classical models as the most popular prediction models. However, the deep prediction model requires users to provide a large amount of private electricity consumption data, which has potential privacy risks. Edge nodes can federally train a global model through aggregation using federated learning (FL). As a novel distributed machine learning (ML) technique, it only exchanges model parameters without sharing raw data. However, existing forecasting methods based on FL still face challenges from data heterogeneity and privacy disclosure. Accordingly, we propose a user-level load forecasting system based on personalized federated learning (PFL) to address these issues. The obtained personalized model outperforms the global model on local data. Further, we introduce a novel differential privacy (DP) algorithm in the proposed system to provide an additional privacy guarantee. Based on the principle of generative adversarial network (GAN), the algorithm achieves the balance between privacy and prediction accuracy throughout the game. We perform simulation experiments on the real-world dataset and the experimental results show that the proposed system can comply with the requirement for accuracy and privacy in real load forecasting scenarios.
    Keywords load forecasting ; personalized federated learning ; differential privacy ; Electronic computers. Computer science ; QA75.5-76.95
    Subject code 006
    Language English
    Publishing date 2023-12-01T00:00:00Z
    Publisher Tsinghua University Press
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article ; Online: An Improved Aeromagnetic Compensation Method Robust to Geomagnetic Gradient

    Yongqiang Feng / Qimao Zhang / Yaoxin Zheng / Xiaodong Qu / Fang Wu / Guangyou Fang

    Applied Sciences, Vol 12, Iss 1490, p

    2022  Volume 1490

    Abstract: Aeromagnetic surveys play an important role in many fields, for example, archaeology, anti-submarine warfare, and geophysical exploration. Being in the geomagnetic field, the aircraft generates a great deal of magnetic interference, resulting in bad ... ...

    Abstract Aeromagnetic surveys play an important role in many fields, for example, archaeology, anti-submarine warfare, and geophysical exploration. Being in the geomagnetic field, the aircraft generates a great deal of magnetic interference, resulting in bad performance during detection surveys. Thus, it is necessary and important to perform aeromagnetic compensation in advance. Conventional aeromagnetic compensation methods consider that the geomagnetic gradient is approximately zero after bandpass filtering, bringing about the inaccuracy of compensation coefficients. To address this issue, an improved aeromagnetic compensation method robust to geomagnetic gradient is proposed. In this study, the International Geomagnetic Reference Field (IGRF) model was employed to model the geomagnetic gradient. Then, the estimated geomagnetic gradient was subtracted from the measured data, which improved the accuracy of the compensation equations. Field experiments were conducted to verify the effectiveness of the proposed method. The experimental results show that compared to the traditional method, the compensation performance of the proposed method was improved by 152% to 329%. For the level flight, the standard deviation of residual noise after compensation can be as low as 3.3pT. The results indicate that the proposed method can significantly improve the compensation effect, showing great benefits for weak magnetic anomaly detection.
    Keywords aeromagnetic compensation ; geomagnetic gradient ; IGRF ; magnetic anomaly detection ; Technology ; T ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Biology (General) ; QH301-705.5 ; Physics ; QC1-999 ; Chemistry ; QD1-999
    Subject code 550
    Language English
    Publishing date 2022-01-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  8. Article ; Online: MG7-Ag, hTERT, and TFF2 identified high-risk intestinal metaplasia and constituted a prediction model for gastric cancer

    Siran Wu / Xiaodong Qu / Na Wang / Luyao Zhang / Xingyu Zhao / Qiong Wu / Junye Liu / Yongquan Shi / Jinjiao Li / Yuanyuan Ji

    Chinese Medical Journal, Vol 136, Iss 5, Pp 610-

    2023  Volume 612

    Keywords Medicine ; R
    Language English
    Publishing date 2023-03-01T00:00:00Z
    Publisher Wolters Kluwer
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  9. Article ; Online: Analysis of risk factors associated with primary bile reflux

    Qiang Dong / Songbo Li / Shasha Chen / Xiaodong Qu / Xingyu Zhao / Yani Li / Shasha Wang / Yongquan Shi / Yuanyuan Ji

    Chinese Medical Journal, Vol 136, Iss 14, Pp 1741-

    A multicenter cross-sectional study

    2023  Volume 1743

    Keywords Medicine ; R
    Language English
    Publishing date 2023-07-01T00:00:00Z
    Publisher Wolters Kluwer
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article ; Online: Phylogenetic and functional diversity could be better indicators of macroinvertebrate community stability

    Yang Liu / Min Zhang / Wenqi Peng / Xiaodong Qu / Yuhang Zhang / Longfei Du / Naicheng Wu

    Ecological Indicators, Vol 129, Iss , Pp 107892- (2021)

    2021  

    Abstract: It is essential to understand biodiversity’s contribution to maintaining river ecosystem functioning and stability, which will us help to develop more effective strategies for river ecosystem conservation. However, knowledge regarding the relationship ... ...

    Abstract It is essential to understand biodiversity’s contribution to maintaining river ecosystem functioning and stability, which will us help to develop more effective strategies for river ecosystem conservation. However, knowledge regarding the relationship between multidimensional characteristics of biodiversity and ecosystem functioning and stability in aquatic ecosystems remains limited. This study examined the relationships between macroinvertebrate multidimensional diversity, secondary productivity, and secondary productivity/biomass (P/B) ratios in natural river ecosystems to examine which kind of diversity could best indicate community stability. In this study, macroinvertebrates were extensively sampled from Chishui River (CSH, an undammed river) and Heishui River (HSH, a dammed river) in April and September 2019. We comparatively analyzed seasonal variations in different types of diversity (species diversity, SD; phylogenetic diversity, PD; and functional diversity, FD), secondary productivity, and P/B ratios between the two rivers. Structural equation models were used to reveal the relationships between multidimensional diversity, secondary productivity, and P/B ratios. The results showed that SD significantly decreased during September both in the undammed CSH which has dramatic seasonal hydrological fluctuations, and in dammed HSH which has stable seasonal hydrological conditions. These findings indicated that SD could not clearly distinguish the key factors that cause changes in biodiversity. Conversely, both PD and FD significantly declined during September in the undammed CSH, but they did not significantly change in the dammed HSH. This result indicated that PD and FD are more sensitive than SD for identifying the effects of disturbances on biodiversity in these natural river ecosystems. After severe hydrological disturbance, although species abundance, biomass, biodiversity, and secondary productivity decreased in CSH, the still high value of P/B ratios indicated the high functional redundancy of ...
    Keywords Macroinvertebrates ; Species diversity ; Phylogenetic diversity ; Functional diversity ; Secondary productivity ; Secondary productivity/biomass ratios ; Ecology ; QH540-549.5
    Subject code 333
    Language English
    Publishing date 2021-10-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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