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Prospects on mangrove knowledge services in the smart era:From plant atlas to knowledge graphs

Science China Earth Sciences 2025年第1期68卷 111-127页

作者： Zhi-Wei HOU Wenlong JING Cheng-Zhi QIN Ji YANG Qing XIA Xiaoling YIN Key Laboratory of Guangdong for Utilization of Remote Sensing and Geographical Information System Guangdong Open Laboratory of Geospatial Information Technology and ApplicationGuangzhou Institute of GeographyGuangdong Academy of SciencesGuangzhou510070China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou511458China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing100049China School of Traffic&Transportation Engineering Changsha University of Science and TechnologyChangsha410114China

Mangroves are crucial to the ecological security of the Earth and human *** management,conservation,and restoration are of great importance and necessitate the support of spatio-temporal information and multidisciplinary knowledge such as biology and *** knowledge services such as plant atlas provide illustrated textual knowledge of ***,this kind of service is oriented to information retrieval and is incapable of effectively mining and utilizing fragmented knowledge from multi-source heterogeneous data,facing the problem of“massive data,rare knowledge”.Knowledge graphs are capable of extracting,organizing,and fusing the knowledge contained in massive data into semantic networks that can be understood and computed by *** provide a solution for the realization of intelligent knowledge *** on the urgent need for mangrove knowledge acquisition,formal representation,and intelligent services,this paper proposes a research prospect on mangrove knowledge graphs and knowledge *** first analyze the similarities and differences between various domain-specific concepts of *** this basis,we define the mangrove knowledge graph as a large-scale knowledge base that integrates multi-disciplinary knowledge and spatio-temporal information with mangrove ecosystems as the ***,we propose a research framework for mangrove knowledge services that can realize the transformation from multi-modal data to intelligent knowledge services,including multiple research levels such as ubiquitous data sensing and aggregation,knowledge organization and graph construction,and intelligent mangrove knowledge ***,the methods and workflow for constructing mangrove knowledge graphs are ***,we discuss the challenges and possible future directions of mangrove knowledge services in the smart era,including the construction of a mangrove knowledge system that integrates the domain-specific charac

关键词： Mangrove Tupu Knowledge graph Multi-modal Knowledge service

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An Adaptive Thin Cloud Removal Method for Mitigating Bright Surface Interference

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IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 2025年 18卷 11487-11501页

作者： Jiang, Tao Shen, Huanfeng Li, Huifang Lin, Dekun Li, Dongyi Wuhan University School of Resource and Environmental Science Wuhan430079 China School of Resource and Environmental Sciences of Wuhan University Key Laboratory of Geographic Information System of Ministry of Education Key Laboratory of Digital Mapping and Land Information Application of the Ministry of Natural Resources Wuhan430079 China Wuhan University School of Resource and Environmental Sciences Collaborative Innovation Center for Geospatial Technology Wuhan430079 China

A thin cloud thickness map (TCTM) is crucial for thin cloud removal tasks, but accurately estimating the TCTM can be a significant challenge. The TCTM is highly susceptible to buildings, which are unavoidable. However, bright surface extraction in existing thin cloud estimation methods is susceptible to thin clouds, affecting the estimation results for the TCTM. In this paper, we propose an adaptive thin cloud removal method for mitigating bright surface interference. Initially, the TCTM is estimated based on the dark pixel search method. The latent low-rank representation (LatentLRR) method is then employed to decompose the TCTM, resulting in a low-rank optimized TCTM. We also propose a new short-wave infrared-based building index (SIBI), which effectively extracts building regions in images that are affected by thin clouds, while remaining largely unaffected by them. Based on this index, an adaptive building suppression weight matrix is constructed to reduce the TCTM for building regions covered by thin clouds. For buildings without cloud cover, the inverse proportional averaging method is used to obtain a fixed weight to suppress the TCTM. Finally, the aerosol thickness in the TCTM is excluded, and the thin cloud reflectivity components for each band are resolved through linear relationships combined with scattering laws, achieving thin cloud removal in single remote sensing images. The experimental results demonstrate that the proposed method can accurately extract the TCTM in various scenarios. The thin cloud removal results exhibit high color and structural consistency with the reference images and achieve optimal spectral fidelity. © 2008-2012 IEEE.

关键词： Inverse problems

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High-beam-quality single-frequency 10-mJ nanosecond fiber and a solid-state hybrid laser front-end system at a 1-kHz repetition rate

Optics Continuum

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Optics Continuum 2025年第4期4卷 915-923页

作者： Kong, Zhiwei Cheng, Tianxiang Zhao, Zhigang Liu, Zhaojun School of Information Science and Engineering Shandong University Qingdao266237 China Key Laboratory of Laser and Infrared System Ministry of Education Shandong University Qingdao266237 China Shandong Provincial Key Laboratory of Laser Technology and Application Shandong University Qingdao266237 China

A compact single-frequency nanosecond fiber & solid-state hybrid laser system at 1030 nm is presented. The seed source, a continuous wave distributed feedback (DFB) laser diode, was first externally modulated with a repetition rate of 1.5 MHz and a pulse duration of 10 ns, whose repetition rate was further lowered to 1 kHz by a pulse picker. Afterwards, three-stage end-pumped Yb:YAG crystal amplifiers were employed for energy scaling. Finally, an average power of 12 W was obtained with a repetition rate of 1 kHz and a linewidth of ∼180 MHz, corresponding to approximately four times the Fourier transform limit (FTL). The beam quality factor (M2) was measured to be 1.18 and 1.20 for the horizontal and vertical directions, respectively. In the future, this high-beam quality front-end laser will be used as the seed source for nanosecond disk laser amplifiers. © 2025 Optica Publishing Group.

关键词： Pulse repetition rate

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Convolution Type of Metaplectic Cohen's Distribution Time-Frequency Analysis Theory, Method and technology

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IEEE Transactions on information Theory 2025年第3期71卷 2292-2314页

作者： Cui, Manjun Zhang, Zhichao Han, Jie Chen, Yunjie Cao, Chunzheng Nanjing University of Information Science and Technology School of Mathematics and Statistics Center for Applied Mathematics of Jiangsu Province Jiangsu International Joint Laboratory on System Modeling and Data Analysis Nanjing210044 China Nanjing University of Information Science and Technology School of Mathematics and Statistics Nanjing210044 China Shanghai Jiao Tong University Key Laboratory of System Control and Information Processing Ministry of Education Shanghai200240 China Hainan Normal University Key Laboratory of Computational Science and Application of Hainan Province Haikou571158 China Nanjing University of Information Science and Technology School of Remote Sensing and Geomatics Engineering Nanjing210044 China

The conventional Cohen's distribution can't meet the requirement of additive noises jamming signals high-performance denoising under the condition of low signal-to-noise ratio, it is necessary to integrate the metaplectic transform for non-stationary signal fractional domain time-frequency analysis. In this paper, we embark on blending time-frequency operators and coordinate operator fractionizations to formulate the definition of the joint fractionizations metaplectic Wigner distribution (JFMWD), based on which we integrate the generalized metaplectic convolution to address the unified representation issue of the convolution type of metaplectic Cohen's distribution (CMCD), whose special cases and essential properties are also derived. We blend Wiener filter principle and fractional domain filter mechanism of the metaplectic transform to design the least-squares adaptive filter method in the JFMWD domain, giving birth to the least-squares adaptive filter-based CMCD whose kernel function can be adjusted with the input signal automatically to achieve the minimum mean-square error (MSE) denoising in Wigner distribution domain. We discuss the optimal symplectic matrices selection strategy of the proposed adaptive CMCD through the minimum MSE minimization modeling and solving. Some examples are also carried out to demonstrate that the proposed filtering method outperforms some state-of-the-arts including the classical Gaussian filter, the Cohen's distribution filtering methods with fixed kernel functions, the classical Wiener filter, the adaptive generalized linear canonical convolution-based filtering method, the adaptive Cohen's distribution filtering method, the adaptive JFMWD-based Cohen's distribution filtering method, and the adaptive generalized metaplectic convolution-based Cohen's distribution filtering method in noise suppression. © 1963-2012 IEEE.

关键词： Adaptive filtering

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Research on Improving Wavelet Thresholding Method for Noise Reduction of Current Ripples in Motors

Research on Improving Wavelet Thresholding Method for Noise ...

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International Conference of Electrical, Electronic and Networked Energy systems, EENES 2024

作者： Qin, Xu Wang, Wei School of Electronic and Information Engineering Tiangong University Tianjin China Tianjin Key Laboratory of Optoelectronic Detection Technology and System Tianjin China Engineering Research Center of Ministry of Education for High Power Semiconductor Lighting Application System Tianjin China

ISBN: (纸本)9789819620456

The vigorous development of new energy vehicles has brought new opportunities and challenges to related industries. In order to gain greater competitive advantages, major automobile manufacturers have begun to focus on using motor current ripple signals directly to achieve various functions in a cheaper and more integrated way. However, the current ripple signal generated when the motor rotates is mixed with a lot of noise. If it is to be put into practical application, it needs to be denoised first, such as the improved wavelet threshold denoising method studied in this paper. First, the denoising principle and the shortcomings of the traditional method are introduced, and the design of the improved method is given on this basis. Subsequently, verification is conducted using simulated signals and actual current ripple signals, with SNR (Signal to Noise Ratio) and RMSE (Root Mean Square Error) used as quantitative evaluation criteria for comparing and analyzing the results. Finally, the experiments have confirmed that the improved threshold method proposed in this paper outperforms traditional methods in noise removal, proving its significance and value for further research. © Beijing Paike Culture Commu. Co., Ltd. 2025.

关键词： Noise abatement

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Improved ADRC PMSM Control system Based on Compensation Function Observer

Improved ADRC PMSM Control System Based on Compensation Func...

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International Conference of Electrical, Electronic and Networked Energy systems, EENES 2024

作者： Wu, Chuangyi Wang, Wei School of Electronic and Information Engineering Tiangong University Tianjin China Tianjin Key Laboratory of Optoelectronic Detection Technology and System Tianjin China Engineering Research Center of Ministry of Education for High Power Semiconductor Lighting Application System Tianjin China

ISBN: (纸本)9789819620791

The Adaptive Disturbance Rejection Control (ADRC) is widely used in nonlinear systems such as Permanent Magnet Synchronous Motors (PMSM) due to its adaptability, strong robustness, and ease of implementation. However, traditional ADRC performs poorly in high-order nonlinear systems, as its performance mainly depends on the nonlinear function representing the total disturbance. To address this issue, this paper proposes an improved ADRC based on the Compensation Function Observer (CFO). The CFO belongs to the type III system, exhibiting significantly improved signal processing performance compared to the type I Extended State Observer (ESO), and it can attenuate the influence of the nonlinear function in the compensation stage. Additionally, in order to alleviate the difficulty of parameter tuning in ADRC, fuzzy control is introduced in the error feedback loop. The feasibility of the proposed method is verified by establishing a Matlab/Simulink simulation model. The simulation results demonstrate that, compared to traditional ADRC, the new ADRC exhibits better response speed and disturbance rejection for common signals. © Beijing Paike Culture Commu. Co., Ltd. 2025.

关键词： MATLAB

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Impact of net-zero emissions on atmospheric CO_(2) concentration in China: Ideal simulations based on the GEOS-Chem model

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Science China Earth Sciences 2025年第3期68卷 867-881页

作者： Jingye TAN Jun WANG Huiqin MAO Hengmao WANG Zhiqiang LIU Meirong WANG Ran YAN Xunmei WANG Fei JIANG Frontiers Science Center for Critical Earth Material Cycling International Institute for Earth System ScienceNanjing UniversityNanjing 210023China Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology Key Laboratory for Land Satellite Remote Sensing Applications of Ministry of Natural ResourcesSchool of Geography and Ocean ScienceNanjing UniversityNanjing 210023China Satellite Environmental Application Center Ministry of Environmental ProtectionBeijing 100094China CMA Key Open Laboratory of Transforming Climate Resources to Economy Chongqing Institute of Meteorological SciencesChongqing 401147China State Key Laboratory of Climate System Prediction and Risk Management Key Laboratory of Meteorological DisasterMinistry of EducationCollaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science and TechnologyNanjing 210044China Xizang Field Station for Scientific Observation and Research on Atmospheric Water Cycle in Mêdog Xigazêand Mêdog National Climate ObservatoryXizang Meteorological ServiceLhasa 850000China

Elevated atmospheric carbon dioxide(CO_(2)) concentrations have caused global climate change such as global warming and more frequent climate extremes. Countries worldwide have proposed carbon neutrality strategies to curb the rising CO_(2) concentrations. To investigate the impact of China's carbon neutrality goal on atmospheric CO_(2) concentrations, we conducted a series of ideal simulations from 2015 to 2019 using a global 3D chemistry transport model, Goddard Earth Observing system Chemistry(GEOS-Chem). Compared with the column-averaged dry-air mole fraction of atmospheric CO_(2) (XCO_(2) ) from Orbiting Carbon Observatory-2(OCO-2) and surface CO_(2) measurements in Obs Pack, we find that GEOS-Chem effectively reproduces the spatiotemporal variability of CO_(2) . The model exhibits a root mean square error(RMSE) of 1.51 ppm(R^(2)=0.89) for OCO-2 XCO_(2) in China and 2.65 ppm(R^(2)=0.75) for surface CO_(2) concentrations at the WLG station. Further, compared to 2.83 ppm yr^(-1)in the control experiment, we suggest that net-zero CO_(2) emissions in China decelerate the increasing trends of XCO_(2) to 1.81 ppm yr^(-1),making a decrease of approximately 35.89%. Meanwhile, the seasonal cycle amplitude(SCA) of XCO_(2) is moderately reduced from 7.39±0.81 to 6.75±0.70 ppm, representing a relative reduction of 9.91%. Spatially, net-zero CO_(2) emissions induce a more significant decrease in XCO_(2) trends over northern and southern China, while their impact on SCA is more evident in northern and northeastern China. Moreover, ideal experiments demonstrate that zero fossil CO_(2) emissions lead to a greater attenuation of the linear trends of XCO_(2) by 40.81%, while the absence of terrestrial CO_(2) sinks largely diminishes the SCA by 16.61%. Additionally,trends and SCA in surface CO_(2) concentrations exhibit almost identical decreasing responses to net-zero CO_(2) emissions but display greater sensitivities compared to XCO_(2) . Overall, our study underscores the pote

关键词： XCO_(2) GEOS-Chem Carbon neutrality Net-zero emissions Surface CO_(2)concentrations

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Gifts from Gallery: Advancing Image Retrieval via Unsupervised Asymmetric Feature Fusion

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IEEE Transactions on Multimedia 2025年

作者： Zhou, Wengang Wu, Hui Wang, Min Li, Houqiang University of Science and Technology of China CAS Key Laboratory of Technology in Geospatial Information Processing and Application System Department of Electronic Engineering and Information Science Hefei230027 China Hefei Comprehensive National Science Center Institute of Artificial Intelligence Hefei230030 China

Asymmetric retrieval systems, characterized by the deployment of models with varying capacities on platforms with differing computational and storage resources, pose a challenge in balancing retrieval efficiency and accuracy. The recent introduction of the Asymmetric Feature Fusion (AFF) paradigm has shown promise by enhancing existing asymmetric retrieval systems through feature fusion on the gallery side. However, its reliance on extensive human-annotated data hinders practical applicability. To this end, we introduce an innovative unsupervised training method tailored for AFF. Leveraging multiple gallery models as feature extractors, our approach exploits similarities among images encoded by these models as pseudolabels. For each gallery model, we calculate its adaptive weight through an in-depth exploration of contextual relationships among ranking list images in its embedding spaces. Subsequently, these weights are utilized to effectively fuse the image similarities encoded by different gallery models into a more robust one. The fused image similarities provide powerful pseudo-supervision for training AFF. Our unsupervised training approach enhances the generality and utility of AFF in real-world scenarios, particularly when labeled data is limited or expensive to obtain. Exhaustive experiments on various landmark retrieval datasets demonstrate the superiority of our method. © 1999-2012 IEEE.

关键词： Multimedia systems

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Monitoring Changes to Small-Sized Lakes Using Medium Spatial and Temporal Satellite Imagery in the Badain Jaran Desert from 2015 to 2020

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International Journal of Crowd Science 2025年第2期9卷 96-109页

作者： Qinyu Zhao Luyan Ji Yonggang Su Kai Yu Yongchao Zhao College of Electronic and Information Engineering Hebei University Baoding China Aerospace Information Research Institute Chinese Academy of Sciences Beijing China Key Laboratory of Technology in Geo-Spatial information Processing and Application System Beijing China Key Laboratory of Target Cognition and Application Technology (TCAT) Beijing China School of Electronic Electrical and Communication Engineering University of Chinese Academy of Sciences Beijing China

The Badain Jaran Desert is the second-largest desert in China, and its lakes, which are generally small-sized and highly dynamic, play a significant role for plants and animals in this arid region. Therefore, long-term monitoring of the distribution of lakes in the Badain Jaran Desert with high spatial and temporal resolution is of great importance. However, due to the tradeoff between pixel size and swath width, currently no single satellite sensor can provide such a time series. Thereby, in this study, we focus on applying the deep learning based spatiotemporal fusion method (super-resolution based spatial fusion with Generative Adversarial Network (GAN)) to a low spatial yet high temporal resolution data (i.e., MODIS 250 m daily reflectance time series) and a high spatial yet low temporal resolution data (i.e., Landsat 30 m 16-day reflectance time series) to generate a daily 30 m time series for 37 selected lakes in the Badain Jaran Desert. Then, an automatic water extraction algorithm is proposed, and a daily 30 m water mapping production is generated for our study area from 2015 to 2020. The overall accuracy can reach 0.92, while the average error of lake areas is less than 9.21%, which is much higher than that derived from the MODIS time series. Moreover, based on our daily high spatial resolution results, it is possible to analyze the water phenology for all sizes of lakes in the Badain Jaran Desert. We have performed a detailed analysis of interannual variability and seasonal changes for the selected 37 lakes in the Badain Jaran Desert. The results show that from 2015 to 2020, the shrinkage of the small lakes (<0.5 km 2 ) is more severe than lakes with a larger size. As for seasonal changes, the lake area can be divided into four stages: quick increase due to ice melting from winter to spring, slow decrease due to evaporation from spring to summer, moderate recovery due to the arrival of the rainy season from summer to autumn, and quick decrease due to lake

关键词： Reflectivity Heuristic algorithms Time series analysis Landsat Lakes Deserts Spatiotemporal phenomena Spatial resolution MODIS Monitoring

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A SAR Deceptive Jamming Suppression Method Based on PRI Variation Design and Multi-Channel Principle

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IEEE Transactions on Geoscience and Remote Sensing 2025年

作者： Shi, Haixu Xu, Zhongqiu Li, Guangzuo Lin, Kuan Liu, Tianqu Hong, Wen Chinese Academy of Sciences Aerospace Information Research Institute Beijing100094 China Key Laboratory of Spatial Information Processing and Application System Technology Beijing100094 China Key Laboratory of Target Cognition and Application Technology Beijing100094 China University of Chinese Academy of Sciences School of Electronic Electrical and Communication Engineering Beijing101499 China

The synthetic aperture radar (SAR) can be affected by various types of jamming during operation. Among them, the deceptive jamming generated by digital radio frequency memory (DRFM) jammers poses a serious threat to SAR imaging by creating highly realistic false targets. Moreover, with advancements in deceptive jamming technology, the generation speed of deceptive jamming has increased, rendering existing methods less effective. To address this issue, an anti-deceptive jamming method based on pulse repetition interval (PRI) variation design and multi-channel principle is proposed to mitigate the effects of deceptive jamming. First, a PRI variation strategy that will not cause the loss of echo signals in the imaging area is designed. By utilizing this strategy for imaging, deceptive jamming signals are dispersed across different ranges, resulting in preliminary suppression of the jamming. Subsequently, after azimuth non-uniform sampling reconstruction and range processing, most of the jamming signals are suppressed due to the azimuth timing differences between SAR and jamming signals. However, when the jammer uses specific retransmission intervals, such as the average PRI of the PRI sequence, the jamming signals may be concentrated at certain ranges, retaining some coherence and posing a threat to SAR imaging. To overcome this challenge, a residual jamming detection and suppression algorithm based on multi-channel principle is proposed, which can detect and filter out the channels affected by jamming. Finally, an azimuth sparse reconstruction is introduced for azimuth processing. Since the anti-jamming principle of this method relies on the differences in azimuth timing between SAR and jamming, it can suppress deceptive jamming even when the generation speed of deceptive jamming is rapid, which some other anti-deceptive jamming methods cannot achieve. Simulations of SAR imaging under deceptive jamming conditions are conducted for point target scene and complex target

关键词： Synthetic aperture radar

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