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Passive Super-Low Frequency electromagnetic prospecting technique

Frontiers of Earth Science 2017年第2期11卷 248-267页

作者： Nan WANG Shanshan ZHAO Jian HUI Qiming QIN Institute of Remote Sensing and GIS School of Earth and Space Sciences Peking University Beijing 100871 China Key Laboratory of Technology in Geospatial Information Processing and Application System Institute of Electronics Chinese Academy of Sciences Beijing 100190 China

The Super-Low Frequency （SLF） electromag- netic prospecting technique, adopted as a non-imaging remote sensing tool for depth sounding, is systematically proposed for subsurface geological survey. In this paper, we propose and theoretically illustrate natural source magnetic amplitudes as SLF responses for the first step. In order to directly calculate multi-dimensional theoretical SLF responses, modeling algorithms were developed and evaluated using the finite difference method. The theore- tical results of three-dimensional （3-D） models show that the average normalized SLF magnetic amplitude responses were numerically stable and appropriate for practical interpretation. To explore the depth resolution, three-layer models were configured. The modeling results prove that the SLF technique is more sensitive to conductive objective layers than high resistive ones, with the SLF responses of conductive objective layers obviously show- ing uprising amplitudes in the low frequency range. Afterwards, we proposed an improved Frequency-Depth transformation based on Bostick inversion to realize the depth sounding by empirically adjusting two parameters. The SLF technique has already been successfully applied in geothermal exploration and coalbed methane （CBM） reservoir interpretation, which demonstrates that the proposed methodology is effective in revealing low resistive distributions. Furthermore, it siginificantly contributes to reservoir identification with electromagnetic radiation anomaly extraction. Meanwhile, the SLF inter- pretation results are in accordance with dynamic production status of CBM reservoirs, which means it could provide an economical, convenient and promising method for exploring and monitoring subsurface geo-objects.

关键词： Super-Low Frequency （SLF） three-dimen-sional modeling frequency-depth transformation geother-mal exploration coalbed methane （CBM） electromagneticradiation （EMR）

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An extended processing scheme for coherent integration and parameter estimation based on matched filtering in passive radar

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Journal of Zhejiang University-Science C(Computers and Electronics) 2014年第11期15卷 1071-1085页

作者： Xin GUAN Li-hua ZHONG Dong-hui HU Chi-biao DING Key Laboratory of Technology in Geo-spatial Information Processing and Application System Institute of Electronics Chinese Academy of Sciences University of Chinese Academy of Sciences

In passive radars, coherent integration is an essential method to achieve processing gain for target detection. The cross ambiguity function(CAF) and the method based on matched filtering are the most common approaches. The method based on matched filtering is an approximation to CAF and the procedure is:(1) divide the signal into snapshots;(2) perform matched filtering on each snapshot;(3) perform fast Fourier transform(FFT) across the snapshots. The matched filtering method is computationally affordable and can offer savings of an order of 1000 times in execution speed over that of CAF. However, matched filtering suffers from severe energy loss for high speed targets. In this paper we concentrate mainly on the matched filtering method and we use keystone transform to rectify range migration. Several factors affecting the performance of coherent integration are discussed based on the matched filtering method and keystone transform. Modified methods are introduced to improve the performance by analyzing the impacts of mismatching, precision of the keystone transform, and discretization. The modified discrete chirp Fourier transform(MDCFT) is adopted to rectify the Doppler expansion in a multi-target scenario. A novel velocity estimation method is proposed, and an extended processing scheme presented. Simulations show that the proposed algorithms improve the performance of matched filtering for high speed targets.

关键词： keystone transform Matched filtering MDCFT Mismatching Passive radar Velocity estimation

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A Long-Term (2012–2024) Data Set of Integrated Land–Atmosphere–Carbon–Hydrology Interactions Observations in Ningxiang, East Monsoon Region

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Geoscience Data Journal 2025年第3期12卷

作者： Li, Ruichao Xie, Zhenghui Jia, Binghao Xie, Zhipeng Wang, Longhuan Tian, Yuhang Yan, Heng You, Yanbin State Key Laboratory of Earth System Numerical Modeling and Application Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China School of Hydrology and Water Resources Nanjing University of Information Science and Technology Nanjing China College of Earth and Planetary Sciences University of Chinese Academy of Sciences Beijing China Key Laboratory of Tibetan Environment Changes and Land Surface Processes Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing China College of Forestry Beijing Forestry University Beijing China

The eastern monsoon region of China, characterised by its high population density and rapid economic development, is particularly sensitive to global climate change. Issues such as water scarcity, droughts and floods, as well as ecological and environmental degradation, are particularly pronounced in this region. Consequently, there is a significant scientific imperative to investigate the land, atmosphere, carbon and hydrology interactions within this region. It is imperative for enhancing the efficiency of water usage, elucidating the evolutionary mechanisms of the carbon and hydrological cycles and evaluating ecological and environmental impacts. In this context, the present study introduces an integrated observation platform of the land–atmosphere–carbon–hydrology interactions in the eastern monsoon region—Ningxiang Station of the Institute of Atmospheric Physics, Chinese Academy of Sciences, and provides a long-term (2012–2024) integrated observation data set of the land–atmosphere–carbon–hydrology interactions. The integrated observation data set comprises hourly basic meteorological elements, half-hourly flux data and half-hourly groundwater depth data. These continuous, long-term, and high-resolution data sets have been employed to investigate land–atmosphere–carbon–hydrology interactions in the eastern monsoon region. Furthermore, the data set provides a critical foundation for the development of a new generation high-resolution earth system models and for advancing understanding of the impacts and feedback mechanisms of natural processes and anthropogenic activities on water, energy, material exchanges and climate. The complete data set is publicly accessible via the Science Data Bank (https://***/10.57760/sciencedb.20182). © 2025 The Author(s). Geoscience Data Journal published by Royal Meteorological Society and John Wiley & Sons Ltd.

关键词： eastern monsoon region flux data groundwater meteorological observations

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A general law of human mobility

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Science China(information Sciences) 2015年第10期58卷 24-37页

作者： LIANG Xiao ZHAO JiChang XU Ke Key Laboratory of Technology in Geo-spatial Information Processing and Application System Institute of Electronics Chinese Academy of Sciences School of Economics and Management Beihang University State Key Laboratory of Software Development Environment Beihang University

The intrinsic factors that drive human mobility have remained unclear for decades. Our observations from both intra-urban and inter-urban trips demonstrate a general law of human mobility. Specifically, the probability that a trip will occur is inversely proportional to the size of population located inside a circle with radius equal to the travel distance centered at the trip origin. A simple parameterless rank-based model is presented; this model can predict human flows with a convincing fidelity. Moreover, existing models can be implemented as special cases of our model, suggesting that our model is stable at more spatial scales. Our model also creates a fundamental bridge between individual mobility and social relationships.

关键词： human mobility social mobility general law rank-based model flux prediction

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Corrigendum to "Simultaneous realization of giant d33, large kp, and high Qm from periodic interface strain generated by co-doping strategy" [Acta Materialia 288 (2025) 120770] (Acta Materialia (2025) 288, (S1359645425000631), (10.1016/***.2025.120770))

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Acta Materialia 2025年 293卷

作者： Huang, Xiaolin Xing, Bohan Wang, Yu Liu, Mingxuan Wen, Xing Jin, Xinyu Li, Danyang Tan, Peng Tian, Hao School of Physics Harbin Institute of Technology Harbin150001 China Laboratory for Space Environment and Physical Sciences Harbin Institute of Technology Harbin150001 China Heilongjiang Provincial Key Laboratory of Plasma Physics and Application Technology Harbin150001 China Key Laboratory of Micro-Nano Optoelectronic Information System Ministry of Industry and Information Technology Harbin150001 China

The authors regret that in Figs. 1 (a, c), the XPS result of pristine KTN and the Εr versus temperature of Fe-doped KTN were misused. The corrected figures are shown as follows. The corrections do not have any impact on the core content and conclusions of the paper. In Fig. 9(c1), the HRTEM image of Fe-doped KTN was misused and did not match the original results of Figs. 9(c2-c4). The HRTEM image of Fe-doped KTN is corrected as follows. Because the conclusions are mainly based on the results of Figs. 9(c2-c4), which are correct in the original version, this correction does not have any impact on the core content and conclusions of the paper. The authors would like to apologise for any inconvenience caused. © 2025 Acta Materialia Inc.

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Research on 3D Reconstruction of Transmission Linesnd Identification of Hidden Dangers of Tree Barriers Based on Airborne Lidar Point Cloud 6th

Research on 3D Reconstruction of Transmission Linesnd Identi...

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6th International Conference on Geo-informatics in Sustainable Ecosystem and Society, GSES 2018

作者： Yang, Chuanxun Li, Yong Zhou, Xia Yang, Ji Zhang, Chen Liu, Hongkai Guangdong Open Laboratory of Geospatial Information Technology and Application Key Laboratory of Guangdong for Utilization of Remote Sensing and Geographical Information System Guangzhou Institute of Geography Guangzhou510070 China

ISBN: (纸本)9789811370243

The inspection procedure of Chinese high voltage power grid is mainly based on human inspection for many years. This is not only time-consuming and difficult, but the inspection results are also not objective and complete. Aiming at these problems, this paper gives a research method based on UAV-borne laser scanning. By taking the orthophotos of the power line corridor area and using the overlapping feature points of the image, the orientation elements of each photo are inversely calculated. According to the principle of aerial triangulation, the pixel matching algorithm is used to calculate the dense point cloud data of the survey area, and the power line point in the point cloud is selected to simulate the complete power line. By calculating the Euclidean distance between the power line and the power line protection area, the calculated result is compared with the power line safety specification to obtain information such as a tree barrier point or an early warning point. It can effectively identify many important defects such as wire-vegetation, wire-building, wire-crossing, etc., and greatly improve the quality and efficiency of the inspection process of existing high-voltage transmission lines. © 2019, Springer Nature Singapore Pte Ltd.

关键词： Inspection

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A SAR imaging method based on generalized minimax-concave penalty

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Science China(information Sciences) 2019年第2期62卷 233-239页

作者： Zhonghao WEI Bingchen ZHANG Yirong WU University of Chinese Academy of Sciences Key Laboratory of Technology in Geospatial Information Processing and Application Systems Institute of Electronics Chinese Academy of Sciences Institute of Electronics Chinese Academy of Sciences

Dear editor,Sparse signal processing offers a framework for synthetic aperture radar （SAR） imaging [1, 2]. As an efficient tool in sparse signal processing, L1minimization is often used in the reconstruction of SAR images. When implemented in SAR imaging [3–5], L1minimization offers significant improvement in the properties by suppressing the sidelobes and clutter. However, L1minimization is known to be a biased estimator. The L1minimization based algorithms such as the iterative

关键词： SAR A SAR imaging method based on generalized minimax-concave penalty

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How many trees are there in China?

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Science Bulletin 2025年第7期70卷 1076-1079页

作者： Kai Cheng Haitao Yang Yuling Chen Zekun Yang Yu Ren Yixuan Zhang Danyang Lin Weiyan Liu Guoran Huang Jiachen Xu Mengxi Chen Zhiyong Qi Guangcai Xu Shengli Tao Hongcan Guan Qin Ma Huawei Wan Tianyu Hu Yanjun Su Zhiheng Wang Keping Ma Qinghua Guo Institute of Remote Sensing and Geographic Information System School of Earth and Space SciencesPeking UniversityBeijing 100871China State Forestry and Grassland Administration Key Laboratory of Forest Resources&Environmental Management Beijing Forestry UniversityBeijing 100083China College of Forestry Southwest Forestry UniversityKunming 650224China Beijing Green Valley Technology Co. Ltd.Haidian DistrictBeijing 100091China Institute of Ecology College of Urban and Environmental SciencesPeking UniversityBeijing 100871China School of Tropical Agriculture and Forestry Hainan UniversityHaikou 570228China School of Geography Nanjing Normal UniversityNanjing 210023China Satellite Environmental Application Center of Ministry of Ecology and Environment Beijing 100094China State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China University of Chinese Academy of Sciences Beijing 100049China

Accurate quantification of tree populations within regions is critical for evaluating forest ecosystem conditions and developing effective forest management strategies[1].High-quality tree census data,collected through field surveys and remote sensing technologies,is fundamental to China's sustainable development and environmental conservation *** data facilitates the monitoring of forest structural changes,carbon sequestration dynamics,and ecosystem health ***,China maintains the world's largest managed forest area,achieved through comprehensive national afforestation and reforestation programs[2,3].Consequently,precise tree enumeration is crucial for formulating effective forest management policies,monitoring and protecting wildlife habitats,and preventing natural disasters in China.

关键词： remote sensing technologiesis quantification tree populations forest management developing effective forest management strategies high quality field surveys monitoring forest structural changescarbon sequestration dynamicsand evaluating forest ecosystem conditions tree population

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Multi-dimensional graph linear canonical transform

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Digital Signal Processing: A Review Journal 2025年 165卷

作者： Li, Na Zhang, Zhichao School of Mathematics and Statistics Center for Applied Mathematics of Jiangsu Province Jiangsu International Joint Laboratory on System Modeling and Data Analysis Nanjing University of Information Science and Technology Nanjing 210044 China Key Laboratory of System Control and Information Processing Ministry of Education Shanghai 200240 China Key Laboratory of Computational Science and Application of Hainan Province Haikou 571158 China

Multi-dimensional (M-D) graph signals represent fundamental data structures in various practical applications, including digital imaging systems, sensor network telemetry, and meteorological observation records. The development of efficient transformation methodologies for processing such M-D graph signals within the linear canonical transform domain continues to present significant challenges. This paper introduces two novel transforms: the two-dimensional graph linear canonical transform based on central discrete dilated Hermite functions (2-D CDDHFs-GLCT) and the two-dimensional graph linear canonical transform based on chirp multiplication-chirp convolution-chirp multiplication decomposition (2-D CM-CC-CM-GLCT). These foundational constructs are extended to the multi-dimensional domain, resulting in M-D CDDHFs-GLCT and M-D CM-CC-CM-GLCT. In terms of computational complexity, additivity and reversibility, M-D CDDHFs-GLCT and M-D CM-CC-CM-GLCT are compared. Theoretical analyses reveal that the M-D CM-CC-CM-GLCT algorithm achieves substantial computational complexity reduction compared to its CDDHFs-based counterpart. Numerical simulations further establish that while maintaining comparable additivity performance, the M-D CM-CC-CM-GLCT exhibits enhanced reversibility characteristics. To validate practical applicability, the proposed M-D GLCT framework is implemented in data compression scenarios. Experimental results demonstrating superior algorithmic efficiency and implementation effectiveness compared to multi-dimensional graph fractional Fourier transform. © 2025 Elsevier Inc.

关键词： Data compression Graph signal processing Linear canonical transform Multi-dimensional signal processing

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RFID Cardinality Estimation Method for Intelligent Warehouse 35

RFID Cardinality Estimation Method for Intelligent Warehouse

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第35届中国控制会议

作者： SHEN Jingjing TAN Xiaobin WU Fan YAN Pei CAS Key Laboratory of Technology in Geo-spatial Information Processing and Application System University of Science and Technology of China

ISBN: (纸本)9781509009107

With the rapid development of RFID technologies,RFID has been introduced into applications such as supply chain management,inventory control,sampling inspection,3-D positioning and object ***,the reader accesses all the tags in its interrogation region while some applications may only need to identify the tags in a specified area which is smaller than the reader's interrogation *** paper concerns the essential problem of estimating cardinality of tags in the specified *** key novelty of our solution builds on an estimation synopsis that can capture key counting information by moving the reader as well as a simple *** the help of this data structure,a BS can be obtained which only contains the target *** computing the number of 1 in the BS,we can easily get cardinality |E| of the tags in the specified *** conduct extensive experiments to examine this design and the results shows that our solution achieves high *** it not requires any modification of tags and can be implemented with only one reader and some passive RFID tags,the proposed method is easy to deploy in a practical system.

关键词： Cardinality estimation RFID tags algorithm design

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