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Acupuncture at Waiguan(SJ5) and sham points influences activation of functional brain areas of ischemic stroke patients: a functional magnetic resonance imaging study 被引量:22
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作者 Ji Qi Junqi Chen +5 位作者 Yong Huang Xinsheng Lai Chunzhi Tang Junjun Yang Hua Chen Shanshan Qu 《Neural Regeneration Research》 SCIE CAS CSCD 2014年第3期293-300,共8页
Most studies addressing the specificity of meridians and acupuncture points have focused mainly on the different neural effects of acupuncture at different points in healthy individuals. This study examined the effect... Most studies addressing the specificity of meridians and acupuncture points have focused mainly on the different neural effects of acupuncture at different points in healthy individuals. This study examined the effects of acupuncture on brain function in a pathological context. Sixteen patients with ischemic stroke were randomly assigned to true point group (true acupuncture at right Waiguan (SJ5)) and sham point group (sham acupuncture). Results of functional magnetic resonance imaging revealed activation in right parietal lobe (Brodmann areas 7 and 19), the right temporal lobe (Brodmann area 39), the right limbic lobe (Brodmann area 23) and bilateral oc-cipital lobes (Brodmann area 18). Furthermore, inhibition of bilateral frontal lobes (Brodmann area 4, 6, and 45), right parietal lobe (Brodmann areas 1 and 5) and left temporal lobe (Brodmann area 21 ) were observed in the true point group. Activation in the precuneus of right parietal lobe (Brodmann area 7) and inhibition of the left superior frontal gyrus (Brodmann area 10) was observed in the sham group. Compared with sham acupuncture, acupuncture at Waiguan in stroke patients inhibited Brodmann area 5 on the healthy side. Results indicated that the altered specificity of sensation-associated cortex (Brodmann area 5) is possibly associated with a central mechanism of acupuncture at Waiguan for stroke patients. 展开更多
关键词 nerve regeneration ACUPUNCTURE Waiguan (SJS) brain injury ischemic stroke function-al magnetic resonance imaging Brodmann area sham point 973 Program neural regeneration
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Mathematical Definitions of Point, Line and Area Symbols in Cartography 被引量:3
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作者 WEIWenzhan ZHONGYexun +1 位作者 PENGYueying ZHENGHongbo 《Geo-Spatial Information Science》 2003年第3期62-65,共4页
The line cartographic symbol located on the boundary and the point cartographic symbol located by single point are the main body and stress of the map. The cartographic symbols are divided into point, line and area sy... The line cartographic symbol located on the boundary and the point cartographic symbol located by single point are the main body and stress of the map. The cartographic symbols are divided into point, line and area symbol in cartography and traditional educational books, but up to now there is only qualitative description about the three kinds of symbols, there are not the mathematical definitions of point, line and area symbols. This paper tries to solve the problem. The authors propose the mathematical definition about point, line and area cartographic symbol according to the theory of topology and expound their dependence relation. 展开更多
关键词 point cartograrphic symbol line cartographic symbol area cartographicsymbol FIGURE
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Reductions in non-point source pollution through different management practices for an agricultural watershed in the Three Gorges Reservoir Area 被引量:13
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作者 Yaowu Tian Zhilin Huang Wenfa Xiao 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2010年第2期184-191,共8页
Non-point source water pollution generated by agricultural production is considered a major environmental issue in the Three Gorges Reservoir Area (TGRA) of China. The Annualised Agricultural Non-Point Source Pollut... Non-point source water pollution generated by agricultural production is considered a major environmental issue in the Three Gorges Reservoir Area (TGRA) of China. The Annualised Agricultural Non-Point Source Pollution (AnnAGNPS) model was selected to assess the impact of the application of various management treats, including seven crops, five fertilizer levels and three-group management practice scenarios, on water quality from Heigou River Watershed in TGRA. The scenario subsets include conservation tillage practice (CTP), conservation reserve program (CRP) and conversion of cropland into forestland program (CCFP). Results indicated that tea can not be replaced by other crops because comparatively tea resulted in a higher sediment yield. CTP with no-tillage was more effective to reduce sediment yield, but could increased nutrient loss. CRP reduced sediment yield significantly, but slightly benefited on nutrient loss. CCFP reduced not only sediment yield but also the nutrient loss significantly. The conversion of cropland with a slope greater than 10° into forestland was found to be the best scenario as the sediment yield export is less than 5 tons/ha and nutrient loss is within the permissible limit. 展开更多
关键词 non-point pollution management practice REDUCTION the Three Gorges Reservoir area
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Discussion on the Green Tax Stimulation Measure of Nitrogen Fertilizer Non-Point Source Pollution Control-Taking the Dongting Lake Area in China as a Case 被引量:8
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作者 XIANG Ping-an ZHOUYan +1 位作者 HUANG Huang ZHENG Hua 《Agricultural Sciences in China》 CAS CSCD 2007年第6期732-741,共10页
A study on designing the tax of nitrogen fertilizer can provide a new method for controlling nitrogen fertilizer non-point source pollution. The tax design of nitrogen fertilizer was discussed by utilizing the externa... A study on designing the tax of nitrogen fertilizer can provide a new method for controlling nitrogen fertilizer non-point source pollution. The tax design of nitrogen fertilizer was discussed by utilizing the external theory and the demand elasticity theory. The results indicated that the coefficient of price elasticity of nitrogen fertilizer demand is -0.21, which instructed that the market demand is in lack of elasticity in the short period and the impact of nitrogen fertilizer manufacturers is subtle. The 11 counties (cities and boroughs) in the Dongting Lake area in China, where the farmland nitrogen application surpassed the average ecological fertilization dosage, is listed to the taxation scope of nitrogen fertilizer tax. The environment loss will reduce 0.07 hundred million RMB yuan and the revenue will increase 0.89 hundred million RMB yuan in the country after levying on nitrogen fertilizer. The loss, which was brought by the decreasing food supplies production, will be 0.58 hundred million RMB yuan and the net social benefit will be 0.38 hundred million RMB yuan following revenue collection. The variation scope of the increasing expenditure of farmers will range from 0.95 to 1.49%. The variation scope of the income of farmers will range from -8.41 to 6.44%. The 5 areas, Yunxi Borough, Junshan Borough, Hanshou County, Jinshi City, and Ziyang Borough, had an increase in food supplies production after the revenue collection. The environment loss will reduce 0.01 hundred million RMB yuan and the revenue will increase 0.16 hundred million RMB yuan in the country after levying on nitrogen fertilizer. The economic benefits, which was brought by the increasing cereals production, will be 0.67 hundred million RMB yuan and the net social benefit will be 0.84 hundred million RMB yuan after revenue collection. The variation scope of the increasing expenditure of farmers will range from 0.95 to 1.06%. The variation scope of the increasing income of farmers will range from 0.69 to 6.44%. Considering the entire social welfare, taxation of nitrogen fertilizer will have more advantages than disadvantages in the Dongting Lake area. 展开更多
关键词 nitrogen fertilizer non-point source pollution TAX Dongting Lake area
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Combination Operation for Neutral Point of 35 kV Power Grids in Mountainous Area 被引量:2
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作者 YUAN Tao SIMA Wen-xia +1 位作者 RAN Rui ZHU Wei 《高电压技术》 EI CAS CSCD 北大核心 2008年第12期2626-2630,共5页
Based on a lot of measurement and analysis,this paper find that the unbalanced nature of 35 kV grids due to unsymmetrical capacitance values gives difficulty in neutral point operation in mountainous area.Improving co... Based on a lot of measurement and analysis,this paper find that the unbalanced nature of 35 kV grids due to unsymmetrical capacitance values gives difficulty in neutral point operation in mountainous area.Improving compensation of Petersen coil can rectify imbalance of voltage but bring up new problem that Petersen coil can not extinguish grounding arc effectively in fault.To put down contradiction mentioned above,this paper proposes a combination operation for neutral point of 35 kV grids as neutral point insulated in routine operation and grounding through Petersen coil in fault,then EMTP simulation is carried out.Simulation indicates that new neutral operation method can improve lightning withstand level and decrease trip-out rate of grids. 展开更多
关键词 山区 补偿电网 消弧线圈 投切运行 暂态分析
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Research on Monitoring Area Division of Quality Grade Changes in County Cultivated Land and Technology of Deploying Monitoring Point
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作者 Wei WEI Lijun LIAO Jianxin YU 《Asian Agricultural Research》 2013年第7期60-62,79,共4页
It is an important means in management of improving both the quality and quantity of cultivated land to monitor grade changes in cultivated land quality. How to deploy monitoring network system and its point reasonabl... It is an important means in management of improving both the quality and quantity of cultivated land to monitor grade changes in cultivated land quality. How to deploy monitoring network system and its point reasonably and roundly are the key to the technology of monitoring grade changes in cultivated land quality by monitoring grade changes in cultivated land quality dynamically in order to obtain the information to the index of cultivated land quality and its changes based on the existing achievements of farmland classification and grading. Spatial analysis method is used to demarcate monitoring area and deploy monitoring point according to ARCGIS,of which the result can meet the demand for monitoring grade changes in cultivated land. 展开更多
关键词 CULTIVATED LAND quality MONITORING MONITORING area
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Fractal Analysis on the Spatial Structure of Land Use Patterns in a Non-Point Source Polluted Area in Southern China
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作者 RONG Kun 《Journal of Landscape Research》 2019年第3期19-22,共4页
Based on the TM remote sensing interpretation of land use data of a non-point source polluted area in southern China in 2015, supported by ArcGIS and the fractal theory, this paper established the perimeter-area fract... Based on the TM remote sensing interpretation of land use data of a non-point source polluted area in southern China in 2015, supported by ArcGIS and the fractal theory, this paper established the perimeter-area fractal equation of the spatial structure of land use types, quantitatively calculated the fractal dimension and stability index of various land use types in this non-point source polluted area in 2015, and analyzed the spatial structure characteristics of land use types. The results showed that the fractal dimension values of the different land use types in the research area ranged 1.141–1.657, and the whole fractal dimension of the research area was 1.206. To be specific, the fractal dimension values of unused land, grass land and rural residential land were high, and the fractal dimension values of dry land, paddy filed and waters were low, and the fractal dimension values of urban land, industrial traffic construction land and forest land were moderate. The area of the land use types whose stability index values were 0.2–0.4 accounted for 89.5% of total area, suggesting that the stability of the spatial structure of land use types of Beibei District in 2015 was not high generally. The rural residential land and urban land of the research area should be planned and managed more properly from now on. 展开更多
关键词 LAND use type SPATIAL structure FRACTAL DIMENSION Stability INDEX Non-point source polluted area
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Non point source ground water pollution trends in an urban area
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《Global Geology》 1998年第1期3-4,共2页
关键词 Non point source ground water pollution trends in an urban area
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Effect of Lumbar Spinal Point Injection on Sitting Function in Children with Cerebral Palsy
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作者 Tian Ma Ceng Li Yabo Liu 《Yangtze Medicine》 2023年第3期171-176,共6页
Objective: To observe the effect of lumbar spinal point injection on sitting function in children with cerebral palsy. Method: Sixty-two children with post-confirmed cerebral palsy were randomly divided into control g... Objective: To observe the effect of lumbar spinal point injection on sitting function in children with cerebral palsy. Method: Sixty-two children with post-confirmed cerebral palsy were randomly divided into control group and treatment group, 31 each. The control group was given conventional rehabilitation treatment, and the treatment group was given lumbar chiropspinal acupoint injection on the basis of the treatment method of the control group. After 3 consecutive courses of treatment, the sitting score of the two groups before and after treatment (GMFM88) was used to evaluate the sitting score before and after treatment. Outcome: Before treatment, the two groups were evaluated and the differences were not statistically significant (p > 0.05), which was comparable. The two groups (GMFM88) after treatment had significantly increased the differential values, and the difference was statistically significant compared with the same group before treatment (p Conclusion: Conventional rehabilitation combined with lumbar spinal point injection can effectively improve the sitting motor function of children with cerebral palsy. 展开更多
关键词 Children with Cerebral Palsy Lumbar Segmentation of Spinal points Acupuncture point Injection Gross Motor Function (Sitting area)
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小型玉米收获机车身调平系统研究
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作者 于春生 胡伟 +5 位作者 付明刚 刘大欣 周德义 吴宝广 侯鹏飞 施新 《农机化研究》 北大核心 2024年第11期104-109,共6页
为了提高小型两行轮式玉米收获机在复杂地形的作业能力,设计了一种三点调平装置,建立了调平模型并对其进行了理论分析,并设计了调平控制系统。在此基础上,设计并制造了试验用车,对倾角信号进行滤波处理后,进行了调平试验。试验结果表明... 为了提高小型两行轮式玉米收获机在复杂地形的作业能力,设计了一种三点调平装置,建立了调平模型并对其进行了理论分析,并设计了调平控制系统。在此基础上,设计并制造了试验用车,对倾角信号进行滤波处理后,进行了调平试验。试验结果表明:车身左倾最大调平角度是15°,右倾最大调平角度是17.5°,前倾最大调平角度是12.5°,后倾最大调平角度是17.5°,验证了自动调平机构和控制系统的可靠性和实用性。设计的针对4YZ-2玉米收获机的三点调平装置和调平控制系统可为玉米收获机自适应调平提供了研究基础,并为其他行走农业机械的调平设计提供了新思路。 展开更多
关键词 玉米收获机 山地丘陵 三点调平 自动控制
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秦岭南麓小流域乡村聚落空间集聚PSR评价研究——以乾佑河流域柞水段为例
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作者 吴锋 康君颖 潘少立 《城市规划》 CSCD 北大核心 2024年第9期67-77,共11页
小流域是山地区域乡村聚落广泛存在的空间载体,随着新型城镇化建设、乡村振兴战略的实施,这里的聚落也开始发生剧烈变动,开始了更为集约的收缩型集聚。为了更好地发现其变化集聚的状态与趋势,对聚落发展提出合理的优化建议与引导,急需... 小流域是山地区域乡村聚落广泛存在的空间载体,随着新型城镇化建设、乡村振兴战略的实施,这里的聚落也开始发生剧烈变动,开始了更为集约的收缩型集聚。为了更好地发现其变化集聚的状态与趋势,对聚落发展提出合理的优化建议与引导,急需合适的评价工具与方法。因此,针对秦岭南麓小流域内聚落斑块零散存在的现实情况,借助“压力-状态-响应”评价模型,提出了聚焦小流域乡村聚落社会-生态健康发展的PSR评价方法以及聚焦关键问题的研究思路;进而以乾佑河柞水段的七条典型小流域为对象,借助核密度估算工具,进行内部聚落空间集聚特征的总结,建构起可进行比较的核点集聚区域、点轴集中区概念;并通过评价参数的筛选,明确了小流域、核点集聚区域双层级PSR评价体系,结合实践提出相关优化建议,也为小流域乡村聚落合理建设探索更科学的研究基础。 展开更多
关键词 小流域 空间集聚 核点集聚区域 点轴集中区 PSR评价
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基于手机信令数据的贝叶斯优化出行链识别
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作者 王殿海 徐望 +2 位作者 蔡正义 曾佳棋 黄宇浪 《浙江大学学报(工学版)》 EI CAS CSCD 北大核心 2024年第11期2393-2405,共13页
为了克服手机信令数据定位信息的时空不确定性对出行识别的影响,分析手机信令数据的时空特性,在时空阈值识别停留点方法的基础上,引入兴趣面(AOI)信息和基站位置数据,提出可变参数滑动窗口的出行停留点识别方法.建立出行链模型,采用贝... 为了克服手机信令数据定位信息的时空不确定性对出行识别的影响,分析手机信令数据的时空特性,在时空阈值识别停留点方法的基础上,引入兴趣面(AOI)信息和基站位置数据,提出可变参数滑动窗口的出行停留点识别方法.建立出行链模型,采用贝叶斯多目标优化获得模型的最佳参数,实现时空阈值的动态调整,提高识别的准确性.为了验证方法的有效性,组织志愿者采集真实出行GPS数据和出行信息标签作为验证数据,与应用模型于对应手机信令数据后的结果进行对比.研究结果表明,手机信令数据的采样在移动和静止状态下存在特性差异;相较于对比方法,提出的出行链识别方法在泛化性能和最优性能方面都表现出较小的误差和较高的识别率,尤其在识别率指标上,相比其他的最新算法改进了3%~26%. 展开更多
关键词 出行链识别 贝叶斯优化 手机信令数据 兴趣面(AOI) 停留点 OD识别
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利用激光点云的智能网联汽车自主换道横向避障
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作者 白雪 赵宇 +2 位作者 温国强 王春絮 王伟 《激光杂志》 CAS 北大核心 2024年第6期238-242,共5页
通过智能网联汽车自主换道横向避障设计,提高车辆自主驾驶安全性能,提出基于激光点云的智能网联汽车自主换道横向避障方法,构建基于全激光雷达的无人驾驶系统的汽车行驶环境激光点云数据采集模型,通过激光雷达激光点云图像检测方法实现... 通过智能网联汽车自主换道横向避障设计,提高车辆自主驾驶安全性能,提出基于激光点云的智能网联汽车自主换道横向避障方法,构建基于全激光雷达的无人驾驶系统的汽车行驶环境激光点云数据采集模型,通过激光雷达激光点云图像检测方法实现对智能网汽车行驶环境感知。结合障碍物检测、车道线检测、可行驶区域检测的方法,分析智能网联下汽车换道障碍物和车道的相关性特征量,通过激光点云的自主寻优方法寻找边界点直到搜索路径达到阈值,再结合直线道路模型和车道线连续性原则实现对汽车自主换道横向避障规划设计。仿真结果表明,采用该方法进行汽车自主环控避障,在5 s时达到收敛状态,障碍物坐标识别误差距离低于0.7,并且该方法的识别精度达到了0.970以上,提高了车道信息的感知能力,准确高效地估计可行驶区域,提高车辆避障能力。 展开更多
关键词 激光点云 智能网联汽车 自主换道 横向避障 可行驶区域
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基于黄金分割搜索的电压暂降域快速识别方法
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作者 雷敏 汤迪虎 +2 位作者 兰征 李勇 吴艺松 《湖南工业大学学报》 2024年第2期25-32,共8页
针对大型复杂电网中敏感负荷的电压暂降域难以准确识别的问题,提出一种基于黄金分割搜索的电压暂降域快速识别方法。首先,求得网络中发生各类短路故障时敏感负荷节点的电压暂降幅值解析式,并引入节点判定向量和线路关联向量,以及相应的... 针对大型复杂电网中敏感负荷的电压暂降域难以准确识别的问题,提出一种基于黄金分割搜索的电压暂降域快速识别方法。首先,求得网络中发生各类短路故障时敏感负荷节点的电压暂降幅值解析式,并引入节点判定向量和线路关联向量,以及相应的判定准则,实现对所有线路临界点的快速分类计算;接着详细阐述了传统插值法存在的问题,并提出一种由黄金分割搜索改进的插值法,以期为正割迭代提供更优的初值点,提高临界点计算的准确度;因考虑到拟合的二次曲线难免存在偏差,故使用故障点法作为补充算法,用以计算有求解困难的线路;最后,以IEEE30节点标准测试系统为例,验证了该方法能在保证计算精度的前提下,简化电压暂降域的求解过程,提高算法的收敛速度,并广泛适用于大型复杂电网。 展开更多
关键词 电压暂降 敏感负荷 临界点 暂降域 黄金分割搜索
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结合载客热点和POI的出租车停车位划定方法
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作者 邢雪 王菲 李佳楠 《吉林大学学报(信息科学版)》 CAS 2024年第1期93-99,共7页
针对出租车随意停靠造成城市交通拥堵甚至交通事故的问题,利用成都实际区域的出租车GPS(Global Position System)数据和爬取的POI(Point of Interest)数据,使用DBSCAN(Density-Based Spatial Clustering of Application with Noise)聚... 针对出租车随意停靠造成城市交通拥堵甚至交通事故的问题,利用成都实际区域的出租车GPS(Global Position System)数据和爬取的POI(Point of Interest)数据,使用DBSCAN(Density-Based Spatial Clustering of Application with Noise)聚类算法对上下客点进行聚类,得到出租车的载客热点,根据POI的类型划定载客热点区域的类型,对出租车不同时间的出行需求进行分析,进而划分出出租车的固定停车区域。研究结果表明,出租车固定停车区域的设定与出行者的出行需求有关,即将固定停车区域设置在出行者出行需求多的区域,可以满足出行者的不同出行需求。结合出租车载客热点和爬取POI数据划定固定停车区域的方法具有较高的实用性,可为城市交通安全方面提供理论和现实意义。 展开更多
关键词 上下客点 DBSCAN聚类算法 载客热点区域 POI数据分析 固定停车区域
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高原地区四点源诱偏系统抗ARM防护性能仿真分析
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作者 陈坤 张永刚 库涛 《空天预警研究学报》 CSCD 2024年第2期117-121,共5页
针对传统反辐射导弹(ARM)攻击仿真模型难以评价高原复杂地形下雷达诱饵的防护效能问题,对传统雷达诱饵诱偏模型进行了改进.首先建立了ARM攻击有源诱偏系统的运动模型,分析了有源诱偏系统对ARM的影响;然后在此基础上,模拟仿真了高原条件... 针对传统反辐射导弹(ARM)攻击仿真模型难以评价高原复杂地形下雷达诱饵的防护效能问题,对传统雷达诱饵诱偏模型进行了改进.首先建立了ARM攻击有源诱偏系统的运动模型,分析了有源诱偏系统对ARM的影响;然后在此基础上,模拟仿真了高原条件下最佳四点源诱偏系统分布模型的抗毁效能.仿真结果表明,通过增大各辐射源高度差可以有效弥补因间距缩短导致的防护概率下降的问题;利用前三角形布站形式,当各辐射源部署间距为100m和高度差为60m时,雷达的防护概率可以达到99.1%,基本满足雷达有源诱偏系统对雷达的防护要求. 展开更多
关键词 高原地区 四点源诱偏系统 反辐射导弹 诱饵雷达 防护效能
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基于移动多线激光雷达扫描的树冠叶面积估计方法
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作者 李秋洁 丁莉 《农业机械学报》 EI CAS CSCD 北大核心 2024年第9期308-315,480,共9页
移动单线激光雷达(Laser detection and ranging,LiDAR)扫描(Mobile single-layer LiDAR scanning,MSLS)树冠叶面积估计方法使用单一视角的单线激光雷达采集树冠点云数据,获取的冠层信息不够全面,限制了树冠叶面积估计精度。本文提出一... 移动单线激光雷达(Laser detection and ranging,LiDAR)扫描(Mobile single-layer LiDAR scanning,MSLS)树冠叶面积估计方法使用单一视角的单线激光雷达采集树冠点云数据,获取的冠层信息不够全面,限制了树冠叶面积估计精度。本文提出一种基于移动多线LiDAR扫描(Mobile multi-layer LiDAR scanning,MMLS)的树冠叶面积估计方法,使用多线LiDAR从多个视角采集树冠点云数据,提升树冠叶面积估计精度。首先,将多线LiDAR采集的点云数据变换到世界坐标系下,通过感兴趣区域(Region of interest,ROI)提取出树冠点云。然后,提出一种MMLS树冠点云融合方法,逐个融合单个激光器采集的树冠点云,设置距离阈值删除重复点,添加新点。最后,构建MMLS空间分辨率网格,建立基于树冠网格面积的树冠叶面积估计模型。实验使用VLP-16型多线LiDAR传感器搭建MMLS系统,设置1、1.5 m 2个测量距离和间隔45°的8个测量角度对6个具有不同冠层密度的树冠进行数据采集,共得到96个树冠样本。采用本文方法,树冠叶面积线性估计模型的均方根误差(Root mean squared error,RMSE)为0.1041 m^(2),比MSLS模型降低0.0578 m^(2),决定系数R^(2)为0.9526,比MSLS模型提高0.0675。实验结果表明,本文方法通过多线LiDAR多视角树冠点云数据采集、MMLS树冠点云融合和空间分辨率网格构建,有效提升了树冠叶面积估计精度。 展开更多
关键词 树冠叶面积 多线激光雷达 移动激光扫描 点云融合 空间分辨率网格
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多无人车协同规划及突发情况下应急响应与恢复方法
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作者 宋文杰 侯鸣妤 +1 位作者 曾林之 李贺瑞 《中国惯性技术学报》 EI CSCD 北大核心 2024年第5期499-510,共12页
面对环境突变、车辆故障等突发情况,传统集中式协同规划方法无法快速应急响应、实现系统冲突消解和有序恢复。针对以上问题,提出一种运动学约束下多无人车协同规划及突发情况下应急响应与恢复方法。首先,采用集中式搜索架构构建运动学... 面对环境突变、车辆故障等突发情况,传统集中式协同规划方法无法快速应急响应、实现系统冲突消解和有序恢复。针对以上问题,提出一种运动学约束下多无人车协同规划及突发情况下应急响应与恢复方法。首先,采用集中式搜索架构构建运动学约束下的协同路径规划模型,引入车身约束树以消解连续空间内多无人车碰撞。其次,为确保受突发情况影响的无人车能够安全快速停靠并降低对系统的干扰,提出一种基于预警区域的应急规划起始点选取方法,基于紧急事件发生时无人车状态生成的随机搜索树进行分层搜索,将随机搜索树、系统内部时空约束、无人车运动稳定性需求相结合,确保无人车能平稳过渡到应急停靠点。最后,在系统恢复过程中,针对不同无人车到达应急响应停靠点的时间差异,采用异步规划策略,将未受突发事件影响的车辆轨迹纳入协同规划的时空约束,最终生成应急响应后的恢复轨迹簇。仿真测试中,最优应急响应轨迹生成平均时长0.324 s,应急响应模块将规划成功率由28.7%提高到87.6%,异步模块在突发障碍物高达15个时将运行效率提升接近93%。 展开更多
关键词 多无人车协同规划 应急响应规划 异步规划 应急停靠点 预警区域
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点融合系统航班进场排序优化元胞自动机模型
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作者 夏正洪 方鹏越 +1 位作者 王楚皓 吴红洪 《计算机工程与设计》 北大核心 2024年第8期2555-2560,F0003,共7页
针对点融合系统中航班调度问题,构建航班进场排序的二维元胞自动机模型,模拟先来先服务(first come first service, FCFS)和滑动窗口(sliding window, SDW)策略下的航班排序过程,对比不同策略下的终端区运行效率。实验结果表明:若都采用... 针对点融合系统中航班调度问题,构建航班进场排序的二维元胞自动机模型,模拟先来先服务(first come first service, FCFS)和滑动窗口(sliding window, SDW)策略下的航班排序过程,对比不同策略下的终端区运行效率。实验结果表明:若都采用FCFS,使用中国民航航空器尾流重新分类标准(RECAT-CN)代替现行尾流间隔,进场航班流在点融合系统中的总运行时间减少了98 s,运行效率提升了4.3%;若都使用RECAT-CN间隔标准,采用SDW优化后的航班进场序列,较FCFS的总运行时间减少了193 s,运行效率提升了8.5%;点融合技术和RECAT-CN间隔标准可以实现终端区运行安全和效率的同步提升。 展开更多
关键词 点融合系统 航空器进场排序 中国民航航空器尾流重新分类 元胞自动机 遗传算法 机场终端区 运行效率
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水稻灌区面源污染治理研究进展
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作者 于凤存 曹秀清 +1 位作者 王矿 肖晨光 《江淮水利科技》 2024年第4期1-5,共5页
水稻生育期与雨热同期导致灌排机率高,也导致化肥中的氮磷伴随地表径流产生大量流失成为稻作区农业面源污染的主要来源。通过对水稻高效节水灌溉制度、农田退水污染迁移转化机理和灌区退水污染协同调控技术等方面国内外研究动态系统分析... 水稻生育期与雨热同期导致灌排机率高,也导致化肥中的氮磷伴随地表径流产生大量流失成为稻作区农业面源污染的主要来源。通过对水稻高效节水灌溉制度、农田退水污染迁移转化机理和灌区退水污染协同调控技术等方面国内外研究动态系统分析,并结合国家和学科发展需求,从退水污染机理解析、灌区水资源调配模拟、灌区面源水污协同调控等方面提出了稻作区面源污染治理研究中亟待解决的关键科学问题,以期为我国农业面源污染防控提供借鉴。 展开更多
关键词 水稻灌区 污染迁移转化 面源污染机理 协同调控
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