检索结果-南通市图书馆

Low-complexity detection based on maximum cumulative measure and Laurent decomposition for multi-h CPM signal

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2022年第6期29卷 64-72页

作者： zheng zhidong Yu Yanming Liu Ning Yuan Honggang Lou Ning Institute of Systems Engineering Academy of Military SciencesBeijing 100082China

In order to solve the problem of high computational complexity in demodulation for multi-h continuous phase modulation(CPM) signal, a maximum cumulative measure combing with the Laurent decomposition(MCM-LD) scheme is proposed to reduce the number of the grid states and the required number of matched filters, which degrades the demodulation complexity at the *** advanced range telemetry(ARTM) Tier Ⅱ CPM signal is adopted to evaluate the performance in simulation. The results show that, compared with the traditional maximum likelihood sequence detection(MLSD), MCM-LD can respectively reduce the numbers of grid states and matched filters from 256 to 32 and 128 to 48 with negligible performance loss, which effectively degrades the computational complexity for multi-h CPM signal.

关键词： multi-h continuous phase modulation(CPM) Laurent decomposition(LD) maximum cumulative measure(CM) low-complexity demodulation

互耦条件下基于4阶累积量的双基地MIMO雷达角度估计

在线全文

学校读者我要写书评

暂无评论

电子与信息学报 2021年第9期43卷 2720-2727页

作者：郑志东中国人民解放军32802部队北京100191

发射和接收阵列的互耦效应将使得双基地多输入多输出(MIMO)雷达的角度估计算法性能下降。针对阵列互耦效应和高斯色噪声并存情况,该文提出一种基于4阶累积量组合矩阵构造的收发角度估计方法。该方法首先根据收发互耦矩阵的Kronecker乘... 详细信息

发射和接收阵列的互耦效应将使得双基地多输入多输出(MIMO)雷达的角度估计算法性能下降。针对阵列互耦效应和高斯色噪声并存情况,该文提出一种基于4阶累积量组合矩阵构造的收发角度估计方法。该方法首先根据收发互耦矩阵的Kronecker乘积特点,并结合互耦矩阵带状、对称的Toeplitz变换性质,充分利用所有的接收数据,构造出多组发射和接收4阶累积量矩阵,通过组合收发累积量矩阵进一步构造出4阶块累积量矩阵,并利用矩阵的奇异值分解,提取出发射和接收旋转不变因子。理论和仿真结果表明:在强互耦效应情况下,所提算法能够有效估计出高斯色噪声背景下目标的收发角度,并实现自动配对。在强互耦情况下,所提算法的估计性能优于其他算法。

关键词：双基地MIMO雷达互耦 4阶累积量角度估计

非均匀矩形阵列下双基地MIMO雷达目标定位方法

在线全文

学校读者我要写书评

暂无评论

电子与信息学报 2018年第8期40卷 1802-1808页

作者：郑志东袁红刚北方电子设备研究所北京100191

该文针对双基地MIMO雷达发射端、接收端皆为非均匀矩形阵列配置情况,将MIMO技术和最小冗余阵列相结合,提出基于双重孔径自由度扩展的目标发射俯仰角、发射方位角、接收俯仰角、接收方位角4参数联合估计新算法。首先利用矩阵Khatri-Rao... 详细信息

该文针对双基地MIMO雷达发射端、接收端皆为非均匀矩形阵列配置情况,将MIMO技术和最小冗余阵列相结合,提出基于双重孔径自由度扩展的目标发射俯仰角、发射方位角、接收俯仰角、接收方位角4参数联合估计新算法。首先利用矩阵Khatri-Rao积的运算特性,构造出2个置换矩阵,对接收信号进行矢量行变换,再通过数据的"去冗余"、"多维平滑"和"折叠"运算,使得新数据具备MIMO雷达自身和最小冗余阵列双重自由度扩展的特点。理论和仿真结果表明:该文算法能够有效估计出目标的4个参数值,且能够实现自动配对;在相同仿真条件下,该文算法的估计精度优于交替最小二乘和多维ESPRIT算法,并且提高了最大可估计的目标数目。

关键词：双基地MIM0雷达矩形阵列最小冗余阵列差分同置角度估计

Meta-analysis of the relationship between cytotoxin-associated gene-A and ischemic stroke subtypes

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2011年第1期6卷 34-40页

作者： Xu Yang Xiaoli Zhao Yongjun Gao zhidong zheng Jilai Li Xinyi Li Xiaoyuan Niu Yingying Su Department of Neurology Aerospace Central Hospital (Aerospace Clinical Medical College of Peking University Peking University) Beijing100049 China Department of Neurology First Affiliated Hospital of Shanxi Medical University Taiyuan 030001 Shanxi Province China Department of Neurology Xuanwu Hospital of Capital Medical University Beijing 100053 China

OBJECTIVE： To assess the role of cytotoxin-associated gene-A （CagA） positive strains of Helicobacter pylori （Hp） in ischemic stroke （IS） subtypes. DATA SOURCES： A computer-based online search of PubMed, EMBASE, the Cochrane Collaboration database, the CNKI database and the VIP database, from January 1997 to July 2010, was performed to find relevant studies. DATA SELECTION： Case-control studies relevant to CagA with IS and IS subtypes were selected. Data regarding related factors in the case group and control group were acquired using the same approach. All patients had been diagnosed as exhibiting IS using skull CT or MRI, and were etiologically typed according to the 1993 TOAST diagnosis criteria. Two investigators independently performed the same search and study selection. Meta-analyses were then performed for the selected studies using RevMan 5.0 software （Cochrane Collaboration） after strict screening. Heterogeneity tests, sensitivity analyses and publication bias assessments were then conducted. MAIN OUTCOME MEASURES： Relationship of CagA with IS and IS subtypes. RESULTS： Eight studies were selected, involving data from 879 patients with IS, and 849 healthy controls. Five out of eight of the selected studies were related to large artery atherosclerosis （461 patients with IS and 497 health controls）. The results of our meta-analysis revealed a significant association between prior infection with CagA-positive strains and increased risk of IS （odds ratio （OR） = 2.31,95% confidence interval （C/）： 1.89-2.82, P 〈 0.01）, In addition, we found an association between infection with CagA-negative strains and IS （OR = 0.57, 95%C1：0.47 0.70, P 〈 0.01）. CagA positive and negative strains were found to correlate with large artery atherosclerosis （CagA-positive strains： OR = 2.87, 95%C/： 2.19-3.77, P 〈 0.01; CagA-negative strains： OR = 0.51, 95%CL 0.39 0.67, P 〈 0.01）. Because of the diversity of etiological factors in the case-control study, we conducted further analyses a

关键词： ischemic stroke subtype helicobacterpylori cytotoxin-associated gene-A meta-analysis

Correlation between Helicobacter pylori infection and atherothrombotic stroke

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2011年第5期6卷 391-395页

作者： Xu Yang Xiaoli Zhao Yongjun Gao zhidong zheng Jilai Li Jichen Du Xinyi Li XianhaoXu Yingying Su Department of Neurology Aerospace Central Hospital (Aerospace Clinical Medical College Affiliated to Peking University) Beijing 100049 China Department of Neurology First Affiliated Hospital of Shanxi Medical University Taiyuan 030001 Shanxi Province China Department of Neurology Xuanwu Hospital Affiliated to Capital Medical University Beijing 100053 China

Previous studies have demonstrated that Helicobacterpylori infection is associated with coronary atherosclerotic heart disease, but the correlation between Helicobacterpylori infection and ischemic stroke remains unclear. The present study assessed the effects of Helicobacter pylori infection on atherothrombotic stroke. This study included 115 individuals with atherothrombotic stroke, all of whom were patients receiving treatment at the Department of Neurology, Aerospace Central Hospital （Aerospace Clinical Medical College Affiliated to Peking University） in China, from March 2006 to July 2009. In addition, 131 controls without the history of cardiovascular disease, cerebrovascular disease or atherothrombosis were also enrolled in the study. Results show that the Helicobacterpylori-lgG positive rate was greater in the atherothrombotic stroke patients than in the controls, but the difference was not statistically significant （67.8% vs. 61.8%, OR = 1.301,95%C/： 0.769-2.203, P = 0.327）. After correction for potential risk factors for Helicobacter pylori infection and known risk factors for ischemic stroke, no significant difference was detected between them （OR = 1.278, 95%C1： 0.667-2.449, P = 0.459）. These results indicate that there is no specific correlation between Helicobacterpylori infection and atherothrombotic stroke. This finding requires further verification in large-sample prospective studies.

关键词： Helicobacter pylori atherothrombotic stroke risk factors

目标角度估计的多输入多输出雷达发射方向图综合

在线全文

学校读者我要写书评

暂无评论

电波科学学报 2015年第4期30卷 789-796页

作者：黄中瑞郑志东张剑云电子工程学院安徽合肥230037 北方电子设备研究所北京100083

针对传统多输入多输出(Multiple-Input Multiple-Output,MIMO)雷达发射功率分散导致目标角度估计性能变差的问题,提出了一种新的MIMO雷达发射方向图综合方法.首先,结合发射功率的空域聚焦范围和发射导向矢量的旋转不变性,严格控制方向... 详细信息

针对传统多输入多输出(Multiple-Input Multiple-Output,MIMO)雷达发射功率分散导致目标角度估计性能变差的问题,提出了一种新的MIMO雷达发射方向图综合方法.首先,结合发射功率的空域聚焦范围和发射导向矢量的旋转不变性,严格控制方向图逼近误差小于给定的门限,并且最小化发射方向图的峰值旁瓣功率;其次,约束协方差矩阵的对角元素相等,以实现发射功率效率最大化,在此基础之上推导了优化模型的二阶锥规划形式,以便采用原对偶内点算法进行有效求解;最后,利用平行因子分析算法对空间目标进行了收发角度估计.仿真结果表明:优化所得加权矩阵不仅能够使发射信号在指定空域进行有效聚焦,而且确保了每个阵元的发射功率相等,因而在发射功率和角度估计方法相同时,所提方法相对传统MIMO雷达具有更好的角度估计精度.

关键词： MIMO雷达二阶锥规划波束聚焦方向图综合角度估计

在线全文

学校读者我要写书评

暂无评论

鹤上三车道小净距隧道爆破振动测试与分析

岩石力学与工程学报 2007年第9期26卷 1882-1887页

作者：龚建伍夏才初郑志东唐颖同济大学地下建筑与工程系上海200092 福州国际机场高速公路有限公司福建福州350004 福建省交通规划设计院福建福州350004

结合福州国际机场高速公路鹤上三车道小净距隧道工程实践,对小净距隧道中间岩柱在爆破荷载作用下的振动响应进行相关监测,分析振动波在不同级别围岩、不同监测位置的传播及分布规律。研究结果表明:隧道中间岩柱边墙部位振动速度大于拱... 详细信息

结合福州国际机场高速公路鹤上三车道小净距隧道工程实践,对小净距隧道中间岩柱在爆破荷载作用下的振动响应进行相关监测,分析振动波在不同级别围岩、不同监测位置的传播及分布规律。研究结果表明:隧道中间岩柱边墙部位振动速度大于拱脚部位,且随着围岩质量提高,振动速度差别逐渐减小;最大振动速度出现在迎爆侧边墙测点的径向方向,可将其作为爆破振动的控制速度;当隧道净距为6 m左右(约0.35B)时,爆破振动对中间岩柱的影响范围为爆破面前后10～20 m,且随围岩质量提高,影响范围相应减小;爆破面前方中间岩柱受爆破振动影响要大于爆破面后方岩体,施工中宜加强该部位监测;同时,宜严格控制爆破总药量和单段最大药量,且分段爆破时,爆破段差应不小于100 ms。该研究结论可为类似条件下小净距隧道的爆破控制和现场监测提供借鉴与参考。

关键词：隧道工程三车道小净距隧道振动测试监控量测

机载MIMO雷达两级降维空时自适应处理方法

在线全文

学校读者我要写书评

暂无评论

数据采集与处理 2014年第4期29卷 542-548页

作者：王珽张剑云郑志东解放军信息工程大学导航与空天目标工程学院郑州450001 合肥电子工程学院合肥230037 北方电子设备研究所北京100083

针对机载多输入多输出(Multiple-input multiple-output,MIMO)雷达杂波抑制问题,提出一种两级降维空时自适应处理方法。首先利用多普勒滤波对杂波信号进行时域降维处理;然后将空域发射-接收二维波束形成权矢量重构为发射权矢量和接收权... 详细信息

针对机载多输入多输出(Multiple-input multiple-output,MIMO)雷达杂波抑制问题,提出一种两级降维空时自适应处理方法。首先利用多普勒滤波对杂波信号进行时域降维处理;然后将空域发射-接收二维波束形成权矢量重构为发射权矢量和接收权矢量Kronecker积形式,并将高维权矢量转化为两个低维权矢量进行分别求解,最后进行权矢量合成。该算法能够有效降低训练样本数需求与运算复杂度,在小样本条件下具有良好的杂波抑制性能,因此更具有实际应用价值。仿真结果验证了算法的有效性。

关键词： MIMO雷达机载雷达空时自适应处理杂波抑制降维

基于稀疏表示的双基地MIMO雷达多目标定位及幅相误差估计

在线全文

学校读者我要写书评

暂无评论

航空学报 2013年第6期34卷 1379-1388页

作者：郑志东张剑云宋靖徐旭宇合肥电子工程学院安徽合肥230037

基于稀疏表示理论,提出一种新的双基地多输入多输出(MIMO)雷达收发角度及幅相误差估计算法。利用接收数据,分别构造发射和接收协方差矩阵,并以列向量化后的发射和接收协方差矩阵为量测信号建立2个一维稀疏线性模型,构造模型求解的L2-L1... 详细信息

基于稀疏表示理论,提出一种新的双基地多输入多输出(MIMO)雷达收发角度及幅相误差估计算法。利用接收数据,分别构造发射和接收协方差矩阵,并以列向量化后的发射和接收协方差矩阵为量测信号建立2个一维稀疏线性模型,构造模型求解的L2-L1混合范数优化目标函数,通过交替迭代寻优获得目标角度估计和幅相误差估计,最后给出了本文算法的收敛性分析。与现有算法相比,该算法充分利用了目标发射和接收空域的稀疏特性,且能够通过对噪声功率的预估计来抑制噪声。仿真结果表明:在低信噪比(SNR)条件下,本文算法仍能够得到较好的估计精度,且对幅相误差具有一定的稳健性。

关键词：幅相误差双基地 MIMO雷达多目标定位稀疏表示稳健性