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基于共轭倒序阵盖氏圆准则的相关信源数估计研究 被引量:3
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作者 胡隽 吴南润 《探测与控制学报》 CSCD 北大核心 2007年第3期16-20,共5页
针对均匀线阵提出了一种基于共轭倒序阵去相关处理的盖氏圆准则应用方法。这种方法使盖氏圆准则在信号之间有相关性的情况下,仍然可以对信源数有准确的估计。从理论上证明了这个方法的可行性,并且把这个方法运用到浅水高分辨率测深侧扫... 针对均匀线阵提出了一种基于共轭倒序阵去相关处理的盖氏圆准则应用方法。这种方法使盖氏圆准则在信号之间有相关性的情况下,仍然可以对信源数有准确的估计。从理论上证明了这个方法的可行性,并且把这个方法运用到浅水高分辨率测深侧扫声纳对附近船只尾流干扰的检测中,取得了比较好的效果。 展开更多
关键词 信源数估计 盖氏圆准则 共轭 DOA估计
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Riesz代数上的d-模(英文)
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作者 冯颖 《数学杂志》 CSCD 北大核心 2012年第5期766-772,共7页
本文引入了Riesz代数上d-模的概念.利用正算子理论讨论了可交换的Riesz代数上的d-模的二次共轭空间的d-模结构,并且研究了由格同态算子或区间保持算子产生的主理想上的特殊d-模.
关键词 Riesz代数 d-模 序共轭 格同态 区间保持算子
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SECURITY ANALYSIS BASED ON OVERSAMPLED CHAOTIC BINARY SEQUENCES 被引量:1
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作者 张宏涛 王慧云 丁润涛 《Transactions of Tianjin University》 EI CAS 2001年第2期123-126,共4页
Some chaotic sequences generated from maps conjugated with tent map can be reconstructed precisely by short sequence prediction,since the problem of finite precision degrades the statistical properties of chaotic ma... Some chaotic sequences generated from maps conjugated with tent map can be reconstructed precisely by short sequence prediction,since the problem of finite precision degrades the statistical properties of chaotic maps.This paper discusses the topological conjugation properties of the chaotic maps;analyzes in detail the reconstruction process of the chaotic sequences and the security of the oversampled chaotic map (OSCM) binary sequences.The result demonstrates that OSCM binary sequences can sustain the attack of the short sequence prediction,that is,they cant be reconstructed.Furthermore,all attack strategies aiming at the chaotic systems based on synchronization will fail,meaning that they are secure. 展开更多
关键词 SECURITY OSCM SEQUENCES topological conjugation
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水下目标回波亮点高分辨方位估计与仿真 被引量:4
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作者 徐瑜 唐波 苑秉成 《鱼雷技术》 2012年第3期190-194,共5页
水下目标回波亮点识别技术是现代声纳系统与水声对抗的一个极为重要的组成部分。基于单源方位精估的短脉冲切割方法,对于发射信号为长脉冲以及正横中轴方位下的目标回波亮点方位估计效果较差。因此研究基于多源的水下目标回波亮点高分... 水下目标回波亮点识别技术是现代声纳系统与水声对抗的一个极为重要的组成部分。基于单源方位精估的短脉冲切割方法,对于发射信号为长脉冲以及正横中轴方位下的目标回波亮点方位估计效果较差。因此研究基于多源的水下目标回波亮点高分辨方位估计方法具有重要的应用价值。本文重点研究了水下目标回波亮点高分辨方位估计方法,首先采用基于共轭倒序阵盖氏圆准则的方法对目标回波进行解相干和亮点数估计,然后在此基础上进行目标回波空间谱估计以获得目标亮点的方位。在具体仿真过程中,采用板块元散射方法仿真目标回波,并在此基础上进行高分辨方位估计,取得了较好的仿真效果。结果表明,本文的研究对于正横中轴方位的潜艇目标识别具有一定的应用价值。 展开更多
关键词 水下目标 高分辨方位估计 板块元算法:共轭 盖氏圆 亮点数估计
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The Monotonicity Problems for Generalized Inverses of Matrices in H (n, ≥) 被引量:1
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作者 庄瓦金 《Chinese Quarterly Journal of Mathematics》 CSCD 1992年第3期18-23,共6页
On the basis of the paoers[3—7],this paper study the monotonicity problems for the positive semidefinite generalized inverses of the positive semidefinite self-conjugate matrices of quaternions in the Lowner partial ... On the basis of the paoers[3—7],this paper study the monotonicity problems for the positive semidefinite generalized inverses of the positive semidefinite self-conjugate matrices of quaternions in the Lowner partial order,give the explicit formulations of the monotonicity solution sets A{1;≥,T_1;≤B^(1)}and B{1;≥,T_2≥A^(1)}for the(1)-inverse,and two results of the monotonicity charac teriaztion for the(1,2)-inverse. 展开更多
关键词 positive semidefinite self-Conjugate matrices of quaternions generalized inverses Lwner partial order MONOTONICITY
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Multifunctional organically modified graphene with super-hydrophobicity 被引量:5
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作者 Huawen Hu Chan C. K. Allan Jianhua Li Yeeyee Kong Xiaowen Wang John H. Xin Hong Hu 《Nano Research》 SCIE EI CAS CSCD 2014年第3期418-433,共16页
In order to bring graphene materials much closer to real world applications, it is imperative to have simple, efficient and eco-friendly ways to produce processable graphene derivatives. In this study, a hydrophilic l... In order to bring graphene materials much closer to real world applications, it is imperative to have simple, efficient and eco-friendly ways to produce processable graphene derivatives. In this study, a hydrophilic low-temperature thermally functionalized graphene and its super-hydrophobic organically modified graphene derivative were fabricated. A unique structural topology was found and some of the oxygen functionalities were retained on the thermally functionalized graphene surfaces, which facilitated the subsequent highly effective organic modification reaction and led to the super-hydrophobic organically modified graphene with multi functional applications in liquid marbles and polymer nanocomposites. The organic modification reaction also restored the graphenic conjugated structure of the thermally functionalized graphene, particularly for organic modifiers having longer alkyl chains, as confirmed by various characteri- zation techniques such as electrical conductivity measurements, ultraviolet/visible spectroscopy and selected area electron diffraction. The free-standing soft liquid marble was fabricated by wrapping a water droplet with the super-hydrophobic organically modified graphene, and showed potential for use as a microreactor. As for the polymer nanocomposites, a strong interfacial adhesion is believed to exist between an organic polymer matrix and the modified graphene because of the organophilic coating formed on the graphene base, which resulted in large improvements in the thermal and mechanical properties of the polymer nanocomposites with the modified graphene, even at very low loading levels. A new avenue has therefore been opened up for large-scale production of processable graphene derivatives with various practicable applications. 展开更多
关键词 low-temperature thermallyfunctionalized graphene organic modification organically modifiedgraphene liquid marbles polymer nanocomposites
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