Wetlands play a critical role in the global environment.The Middle Yangtze River Basin(MYRB),known for its abundant wetland resources,has experienced notable changes resulting from the complex interplay of environment...Wetlands play a critical role in the global environment.The Middle Yangtze River Basin(MYRB),known for its abundant wetland resources,has experienced notable changes resulting from the complex interplay of environmental factors.Therefore,we investigated the spatiotemporal characteristics of wetland ecological quality in the MYRB from 2001 to 2020.Utilizing the random forest(RF)regression algorithm and patch-generated land-use simulation(PLUS)model,we forecasted variations in wetland habitat quality and their determinants under the Shared Socioeconomic Pathway-Representative Concentration Pathway(SSPRCP)framework from 2035 to 2095.The main findings are as follows:(1)The RF algorithm was optimal for land-use and land-cover(LULC)classification in the MYRB from 2001 to 2020,when notable changes were observed in water bodies and buildings.However,the forested area exhibited an increase and decrease of 3.9%and 1.2%under the SSP1-2.6 and SSP5-8.5 scenarios,respectively,whereas farmland exhibited a diminishing trend.(2)Wetlands were primarily concentrated in the central and eastern MYRB,with counties in the southwest exhibiting superior ecological-environmental quality from 2001 to 2020.Notably,wetland coverage revealed significantly high level,significant changes,frequent but relatively minor changes under the SSP1-2.6,SSP2-4.5,and SSP 5-8.5 scenarios,respectively.(3)Regions with lower habitat quality were primarily concentrated in urbanized areas characterized by frequent human activities,indicating a clear degradation in habitat quality across different scenarios.In conclusion,we established a foundational framework for future investigations into the eco-hydrological processes and ecosystem quality of watersheds.展开更多
预测与健康管理(prognostics and health management,PHM)指标是否科学将直接影响PHM的设计效果,进而影响装备的可用性。针对实践中缺乏理论性与可实现性强的PHM指标论证方法,提出从装备综合效能指标到PHM综合指标、再到PHM能力指标的...预测与健康管理(prognostics and health management,PHM)指标是否科学将直接影响PHM的设计效果,进而影响装备的可用性。针对实践中缺乏理论性与可实现性强的PHM指标论证方法,提出从装备综合效能指标到PHM综合指标、再到PHM能力指标的分级论证方法。选取可用度作为装备综合效能指标,定义了健康状态评估率并将其作为PHM综合指标,推导出可用度与健康状态评估率的关系式,以可用度最大化为目标求解出健康状态评估率指标。证明了健康状态评估率等于故障覆盖率与评估准确度的乘积,二者分别取决于感知单元的数量和诊断预测方法的准确性,这对开展PHM设计有指导意义。通过案例检验了上述方法的有效性和实用性。展开更多
针对通信系统国产化的需求,采用国产射频收发芯片,从硬件与软件两个方面开发,设计了一套完整的软件无线电(Software Defined Radio,SDR)系统。以Zynq-7000芯片作为数字基带验证平台,利用Verilog和C语言进行开发,通过自主设计调制解调IP...针对通信系统国产化的需求,采用国产射频收发芯片,从硬件与软件两个方面开发,设计了一套完整的软件无线电(Software Defined Radio,SDR)系统。以Zynq-7000芯片作为数字基带验证平台,利用Verilog和C语言进行开发,通过自主设计调制解调IP核,实现了全双工模式下无线数据收发功能。依据国产射频收发芯片系统架构,提出了一种改进型正交相移键控(Quadrature Phase Shift Keying,QPSK)结构,并通过自定义通信协议成功实现数据收发。该系统性能稳定可靠,能够在户外500 m以上的范围内有效通信,未出现误码,且功耗低于7.5 W。展开更多
基金National Natural Science Foundation of China,No.42207078CUG Scholar-Scientific Research Funds at China University of Geosciences(Wuhan),No.2022166+1 种基金China Scholarship Council,No.202306410026Opening Fund of State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,China Institute of Water Resources and Hydropower Research,No.IWHR-SKL-KF202217。
文摘Wetlands play a critical role in the global environment.The Middle Yangtze River Basin(MYRB),known for its abundant wetland resources,has experienced notable changes resulting from the complex interplay of environmental factors.Therefore,we investigated the spatiotemporal characteristics of wetland ecological quality in the MYRB from 2001 to 2020.Utilizing the random forest(RF)regression algorithm and patch-generated land-use simulation(PLUS)model,we forecasted variations in wetland habitat quality and their determinants under the Shared Socioeconomic Pathway-Representative Concentration Pathway(SSPRCP)framework from 2035 to 2095.The main findings are as follows:(1)The RF algorithm was optimal for land-use and land-cover(LULC)classification in the MYRB from 2001 to 2020,when notable changes were observed in water bodies and buildings.However,the forested area exhibited an increase and decrease of 3.9%and 1.2%under the SSP1-2.6 and SSP5-8.5 scenarios,respectively,whereas farmland exhibited a diminishing trend.(2)Wetlands were primarily concentrated in the central and eastern MYRB,with counties in the southwest exhibiting superior ecological-environmental quality from 2001 to 2020.Notably,wetland coverage revealed significantly high level,significant changes,frequent but relatively minor changes under the SSP1-2.6,SSP2-4.5,and SSP 5-8.5 scenarios,respectively.(3)Regions with lower habitat quality were primarily concentrated in urbanized areas characterized by frequent human activities,indicating a clear degradation in habitat quality across different scenarios.In conclusion,we established a foundational framework for future investigations into the eco-hydrological processes and ecosystem quality of watersheds.
文摘预测与健康管理(prognostics and health management,PHM)指标是否科学将直接影响PHM的设计效果,进而影响装备的可用性。针对实践中缺乏理论性与可实现性强的PHM指标论证方法,提出从装备综合效能指标到PHM综合指标、再到PHM能力指标的分级论证方法。选取可用度作为装备综合效能指标,定义了健康状态评估率并将其作为PHM综合指标,推导出可用度与健康状态评估率的关系式,以可用度最大化为目标求解出健康状态评估率指标。证明了健康状态评估率等于故障覆盖率与评估准确度的乘积,二者分别取决于感知单元的数量和诊断预测方法的准确性,这对开展PHM设计有指导意义。通过案例检验了上述方法的有效性和实用性。
