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季节性淹水湿地表层土壤有机碳含量遥感预测及空间分布特征

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华中农业大学学报 2024年第3期43卷 111-120页

作者：邹霞钱海燕周杨明黄灵光杨梅花东华理工大学地球科学学院南昌330013 江西师范大学地理与环境学院南昌330200 江西省自然资源政策调查评估中心南昌330046 豫章师范学院生态与环境学院南昌330103

为探讨鄱阳湖季节性淹水湿地土壤有机碳的空间分布特征及遥感方法在土壤有机碳估算中的适用性,依托江西鄱阳湖国家级自然保护区,选择蚌湖、常湖池和泗洲头湿地为研究区域,基于野外实测土壤有机碳含量数据和同期的Landsat8OLT遥感影像,... 详细信息

为探讨鄱阳湖季节性淹水湿地土壤有机碳的空间分布特征及遥感方法在土壤有机碳估算中的适用性,依托江西鄱阳湖国家级自然保护区,选择蚌湖、常湖池和泗洲头湿地为研究区域,基于野外实测土壤有机碳含量数据和同期的Landsat8OLT遥感影像,采用遥感图像处理和GIS技术提取影像中遥感特征因子,构建遥感参数与土壤有机碳的一元线性、一元曲线和多元逐步线性回归模型,通过对比分析选择最优遥感估算模型,预测鄱阳湖季节性淹水湿地表层(0~20 cm)土壤有机碳含量。结果表明,提取了影像中33个遥感特征因子,包括7个波段的反射率值(b_(1)~b_(7))、4个植被指数(NDVI、SR、SAVI、EVI)、第一主成分特征(PCA1)、单波段纹理特征的均值(MEAN)、熵(ENT)和相关性(COR),其中纹理特征是研究区土壤有机碳含量预测的重要遥感因子,其与土壤有机碳含量构建的多元逐步线性回归模型拟合效果最优,模型决定系数R^(2)=0.772,平均相对误差45.53%,均方根误差2.417。遥感反演发现,研究区预测表层土壤有机碳含量主要集中在0~20g/kg,土壤有机碳含量平均值约为10.75g/kg。

关键词：鄱阳湖湿地土壤有机碳遥感预测遥感特征因子碳循环土壤碳储量土壤固碳能力

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鄱阳湖双退区受损湿地土壤氮素空间分布特征及影响因素

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江西农业大学学报 2024年第2期46卷 530-542页

作者：于婷婷钱海燕周杨明杨梅花东华理工大学地球科学学院江西南昌330013 江西师范大学地理与环境学院江西南昌330200 豫章师范学院生态与环境学院 330103

【目的】土壤氮素是湿地营养水平的重要指标,研究鄱阳湖双退区受损湿地土壤氮素空间分布特征及其影响因素,为开展鄱阳湖受损湿地植被生态恢复与重建提供科学依据。【方法】在鄱阳湖退田还湖区中的双退区选择位于江西省都昌县多宝乡的马... 详细信息

【目的】土壤氮素是湿地营养水平的重要指标,研究鄱阳湖双退区受损湿地土壤氮素空间分布特征及其影响因素,为开展鄱阳湖受损湿地植被生态恢复与重建提供科学依据。【方法】在鄱阳湖退田还湖区中的双退区选择位于江西省都昌县多宝乡的马影湖湿地4类受损湿地土壤,分别为沼泽土、草甸土、草甸沼泽土和次生草甸沼泽土,研究0~20 cm(表层土)、20~40 cm(中层土)和40~60 cm(深层土)3个土壤剖面的全氮(TN)、硝态氮(NO_(3)^(-)-N)和氨态氮(NH_(4)^(+)-N)的空间分布特征,利用聚类推进树算法量化环境因子对氮素的相对贡献,利用Pearson相关性分析氮素与环境因子的关系、利用结构方程模型分析了环境因子对氮素的影响路径。【结果】除沼泽土NH_(4)^(+)-N以中层土最高及次生草甸沼泽土土壤TN、NO_(3)^(-)-N、NH_(4)^(+)-N分别以中层土和深层土最高外,其余土壤类型皆以表层(0~20 cm)土壤氮素含量最高,分别为TN(0.35±0.03)g/kg、NH_(4)^(+)-N(4.02±0.38)mg/kg和NO_(3)^(-)-N(4.84±0.53)mg/kg。土层深度、有效磷(AP)对氮素分布和积累具有重要影响,pH通过影响土壤有机碳(SOC)、AP、有效钾(AK)间接影响到氮素,阳离子交换量(CEC)通过影响SOC间接影响到氮素。【结论】与鄱阳湖天然湿地相比,区内4类受损湿地土壤氮素含量均处于极低水平,各氮素最高值多集中在土壤表层,其中TN以草甸土含量最高也最易淋失,其次为草甸沼泽土、次生草甸沼泽土,沼泽土最少且最易被流水冲洗,氮素的积累和分布受土层深度、AP、pH、CEC等影响较大。

关键词：湿地土壤氮素影响因素结构方程模型双退区鄱阳湖退化湿地

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Multi-stream signals separation based on space-time-isomeric (SPATIO) array using metasurface antennas

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Science China(Information Sciences) 2024年第2期67卷 181-200页

作者： yangming LOU Liang JIN Huiming WANG zhou ZHONG Junyan DAI PLA Strategic Support Force Information Engineering University School of Information and Communications Engineering Xi'an Jiaotong University 3. State Key Laboratory of Millimeter WavesSoutheast University

In spatial domain signal processing, it is necessary to equip more antennas at the receiver to improve spatial demultiplexing capability. However, increasing the number of antennas under restricted space will reduce antenna spacing and raise the channel correlation, making the number of signal streams spatially demultiplexed much smaller than that of antennas. This paper proposes a method to design a space-timeisomeric(SPATIO) array based on metasurface antennas under wireless multipath conditions. Each antenna in this array has a different pattern and varies independently with time, reducing the channel correlation by superposing multipath at distinct positions and moments. Based on the SPATIO array, we present an array parameter design scheme based on infinity norm minimization, which can maximize the received energy of each stream while separating multi-stream received signals. Simulation results illustrate the performance of the SPATIO array for multi-stream signal reception. Compared with conventional multiple-input multipleoutput arrays, the proposed array can reduce the bit error rate by one order of magnitude under the same simulation conditions.

关键词： multiple-input multiple-output metasurface antenna space-time-isomeric array multipath channel degree of freedom

人工智能生成内容模型的数字水印技术研究进展

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网络空间安全科学学报

网络空间安全科学学报 2024年第1期2卷 13-39页

作者：郭钊均李美玲周杨铭彭万里李晟钱振兴张新鹏复旦大学计算机科学技术学院上海200433 复旦大学数字文化保护与旅游数据智能计算文化和旅游部重点实验室上海200433

人工智能(AI)正在改变世界,人工智能生成内容(AIGC)是当前最前沿的技术之一。探讨人工智能生成内容的演变历程,介绍从AI到AIGC的技术变迁,讨论AIGC引发的相关问题和挑战以及应对策略。同时,关注全球范围内的法律法规和国际动向,分析不... 详细信息

人工智能(AI)正在改变世界,人工智能生成内容(AIGC)是当前最前沿的技术之一。探讨人工智能生成内容的演变历程,介绍从AI到AIGC的技术变迁,讨论AIGC引发的相关问题和挑战以及应对策略。同时,关注全球范围内的法律法规和国际动向,分析不同国家和组织在人工智能监管方面采取的举措,尤其是中国在全球AI治理中的贡献。着重介绍的是AIGC模型的数字水印(DigitalWatermarking)技术。数字水印已有多年发展的历史,在多媒体确权、防伪、认证等方面发挥了重要作用,随着AIGC的兴起,数字水印在模型保护、内容溯源、样本保护等方面又开始发挥新的作用。关于AIGC模型的数字水印技术研究进展的介绍,将为理解AIGC安全领域的发展提供新的视角维度,为研究AIGC领域的应用实践提供参考。

关键词：数字水印大模型安全大模型版权保护大模型水印生成物版权保护生成物溯源

Reevaluation by the CRISPR/Cas9 knockout approach revealed that multiple pluripotency-associated lncR NAs are dispensable for pluripotency maintenance while Snora73a/b is essential for pluripotency exit

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Science China Life Sciences 2024年

作者： Zhen Li Xuefei Li Jingxia Lin yangming Wang Huiqing Cao Jiajian zhou Institute of Molecular Medicine College of Future Technology Peking University Dermatology Hospital Southern Medical University Beijing Advanced Center of RNA Biology (BEACON) Peking University

Many long noncoding RNAs(lncRNAs) have been identified through siRNA-based screening as essential regulators of embryonic stem cell(ESC) pluripotency. However, the biological and molecular functions of most lncRNAs remain unclear. Here, we employed CRISPR/Cas9-mediated knockout technology to explore the functions of 8 lncRNAs previously reported to promote pluripotency in mouse ESCs. Unexpectedly, all of these lncRNAs were dispensable for pluripotency maintenance and proliferation in mouse ESCs when disrupted individually or in combination. Single-cell transcriptomic analysis also showed that the knockout of these lncRNAs has a minimal impact on pluripotency gene expression and cell identity. We further showed that several small hairpin RNAs(shRNAs) previously used to knock down lncRNAs caused the downregulation of pluripotency genes in the corresponding lncRNA-knockout ESCs, indicating that off-target effects likely responsible for the pluripotency defects caused by these shRNAs. Interestingly, linc1343-knockout and linc1343-knockdown ESCs failed to form cystic structures and exhibited high expression of pluripotency genes during embryoid body(EB) differentiation. By reintroducing RNA products generated from the linc1343 locus, we found that two snoRNAs, Snora73a and Snora73b, but not lncRNAs, could rescue pluripotency silencing defects during EB differentiation of linc1343 knockout ESCs. Our results suggest that the 8 previously annotated pluripotency-regulating lncRNAs have no overt functions in conventional ESC culture; however, we identified snoRNA products derived from an annotated lncRNA locus as essential regulators for silencing pluripotency genes.

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Examining Health of Wetlands with Multiple Ecosystem Services as Targets in China’s Coastal Regions

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Chinese Geographical Science 2020年第4期30卷 600-613页

作者： zhou yangming DOU Yuehan YU Xiubo ZHANG Li HUANG Chong WANG Yuyu LI Xiaowei LI He JIA Yifei BAKKER Martha CARSJENS Gerrit Jan zhou Yan DUAN Houlang School of Geography and Environment Jiangxi Normal UniversityNanchang 330022China Land Use Planning Group Wageningen University and ResearchWageningen 6700HBthe Netherlands Key Laboratory of Ecosystem Network Observation and Modelling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100190China Key Laboratory for Biodiversity Science and Ecological Engineering Ministry of EducationCollege of Life SciencesBeijing Normal UniversityBeijing 100875China State Key Laboratory of Resources and Environment Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China School of Nature Conservation Beijing Forestry UniversityBeijing 100083China Key Laboratory of Coastal Environmental Processes and Ecological Remediation Yantai Institute of Coastal Zone ResearchChinese Academy of SciencesYantai Shandong 264003China College of Biology and Environment Nanjing Forestry UniversityNanjing 210037China

Coastal zones are key interconnectors of terrestrial and marine *** to the degradation and fragmentation of coastal wetlands,there is an urgent need to develop assessment methodology to compare the health of wetland ecosystems at different spatial *** will help efficiently develop and implement protections using easy-to-access ecosystem health *** study aims to understand the spatial distribution of coastal and inland wetland health for China’s coastal regions.A Wetland Health Index(WHI)was developed to provide a basis for policy and decision *** utilization models—Long Term Model,Open Model,Nature Reserve Model,and Protected and Economic Model—were defined in the context of China’s coastal regions to specifically examine wetland *** show that the average WHI score was 63.6 with the range of 44.8–84.3 for 35 National Nature Reserves(NNRs),and the southern NNRs generally performed better than the northern *** wetlands in the southern provinces/municipalities are relatively healthier than their northern *** competent authority has slight influence on WHI scores but duration of conservation establishment does not show a clear *** increasing economic activity,the differences in health conditions(WHI scores)of China’s coastal regions also *** Domestic Product(GDP)or economic intensification does not relate to WHI *** trade-offs between wetland management and economic development could contribute to improve health conditions,conservation and utilization of coastal and inland wetlands.

关键词： Wetland Health Index(WHI) ecosystem services wetland utilization coastal zones

A physical layer secret key consistency enhancement scheme using constellation decision information

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Security and Safety

Security and Safety 2024年第1期 88-103页

作者： Zheyuan Deng Liang Jin Xiaoyan Hu zhou Zhong yangming Lou Ge Niu PLA Strategic Support Force Information Engineering University

Secret key generation based on a wireless channel(WC-SKG) is a promising solution to address the security issues in wireless communication. However, the consistency of channel estimation between two legal communication nodes in WC-SKG is often poor due to the receiver noise, signal power, etc., leading to a low secret key generation rate(SKGR). Although there are several denoising algorithms such as orthogonal transformation to address this issue, existing schemes overlook the fact that data symbols are also affected by the channel. This results in existing schemes only using the pilot symbols for channel estimation and not fully utilizing the received signal power of the WC-SKG. To address this issue, we propose a consistency enhancement algorithm based on constellation decision information(CEA-CDI), which utilizes both pilot symbols and soft decision information of data symbols to improve SKGR. Monte Carlo simulation and numerical results demonstrate that our proposed scheme can improve performance by approximately 16 dB compared to initial channel estimation.

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房地产企业风险压力测试实证研究:限购令、房产税、新土管政策的持续性冲击影响

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管理评论 2014年第9期26卷 58-68页

作者：周阳敏郑州大学商学院郑州450001

在压力测试理论和房地产企业风险管理理论的基础上,本文构建了房地产企业风险压力测试的理论体系,对我国房地产企业(上市公司)进行了风险压力测试的理论探索与实证分析。本文压力测试表明:在面对各类房地产调控政策冲击时,房地产企业(... 详细信息

在压力测试理论和房地产企业风险管理理论的基础上,本文构建了房地产企业风险压力测试的理论体系,对我国房地产企业(上市公司)进行了风险压力测试的理论探索与实证分析。本文压力测试表明:在面对各类房地产调控政策冲击时,房地产企业(上市公司)整体抗风险能力都很弱,"限购令"政策对我国房地产企业冲击形成的风险与危害最大,影响次之的是"房产税"政策,虽然"土地管理"政策冲击导致房地产企业风险排第三,但影响程度也较大;即使在相同风险压力下,民营房地产企业(上市公司)的抗风险能力要相对优于国有的房地产企业(上市公司);在越来越严格、越来越细化、越来越有针对性的房地产调控政策冲击下,我国房地产企业的抗风险能力或风险暴露水平出现两级分化。最后,本文对我国房地产企业的风险管理提出了相应的政策与建议。

关键词：风险压力测试因子分析房地产企业

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鲁棒视频水印研究进展

中国图象图形学报 2022年第1期27卷 27-42页

作者：王翌妃周杨铭钱振兴李晟张新鹏复旦大学计算机科学技术学院上海200082

数字视频在当前通信世界中被认为是一种重要而有效的媒体,广泛应用于新闻、短视频和有线网络广播视频节目中。随着计算机与互联网技术的发展,数字视频内容容易被侵权使用者肆意复制和传播,如何保护视频版权日益成为人们关注的问题。鲁... 详细信息

数字视频在当前通信世界中被认为是一种重要而有效的媒体,广泛应用于新闻、短视频和有线网络广播视频节目中。随着计算机与互联网技术的发展,数字视频内容容易被侵权使用者肆意复制和传播,如何保护视频版权日益成为人们关注的问题。鲁棒视频水印是实现视频版权保护的一种有效手段。作为数字视频水印的分支,鲁棒视频水印是一种通过特定算法在需要被保护的视频对象中嵌入秘密信息———水印来证明版权归属的技术。本文对当前的视频水印技术进行了概述,对视频水印的概念、应用场景、分类方式、设计要求、发展历程和相关经典方法进行了介绍和梳理。本文归纳总结了2016—2021年鲁棒视频水印相关研究工作,包括基于内容的、基于码流的、基于深度学习和其他类型视频水印,并对其中部分工作进行了相应的性能比较和分析。其中,基于内容的视频水印方法将视频看做帧序列,由于在每一帧上应用水印算法,不考虑视频的编解码过程,这类方法实现简单,计算效率高;基于码流的视频水印方法将水印嵌入到编码比特流中,该方案更快速,故可支持实时视频水印应用;基于深度学习的方法取代了依靠手工设计的特征来提高水印的性能。最后分析了鲁棒视频水印的未来发展趋势。

关键词：版权保护信息隐藏数字水印视频水印鲁棒视频水印