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一种在长时间序列SAR影像上提取稳定目标点的多级探测法 被引量:13
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作者 卢丽君 廖明生 +1 位作者 王腾 田馨 《遥感学报》 EI CSCD 北大核心 2008年第4期561-567,共7页
基于长时间序列上的差分雷达地表形变检测技术是近年来形变监测领域中一项重要的关键技术,而在长时间序列上稳定目标点的准确提取则是其中的一项重要环节,在此本文提出了一个有效的提取稳定目标点的多级探测方法。该方法以传统的振幅探... 基于长时间序列上的差分雷达地表形变检测技术是近年来形变监测领域中一项重要的关键技术,而在长时间序列上稳定目标点的准确提取则是其中的一项重要环节,在此本文提出了一个有效的提取稳定目标点的多级探测方法。该方法以传统的振幅探测法为基础提取稳定目标点,同时针对振幅探测中稳定目标点的分布密度低、不均匀等问题,建立时间相干性计算模型,并利用目标点时间相干信息提取更多满足要求的稳定点目标。本文选用上海地区的26幅ERS-1/2 C波段SAR图像(1992—2000年获取)进行了目标点的提取实验,证实了该方法的有效性和可靠性。 展开更多
关键词 长时间序列 目标点提取 振幅探测 多级探测 时间相干性
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光擦除双光束耦合多级光探测器的研究 被引量:1
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作者 吉选芒 王金来 +1 位作者 刘劲松 安毓英 《光学学报》 EI CAS CSCD 北大核心 2001年第6期737-740,共4页
基于光擦除和双光束耦合的基本原理 ,提出了一种多级光探测的方法。用带导模型和耦合波方程建立了理论公式。用三块Ce∶KNSBN晶体和He Ne激光进行了实验演示。理论分析与实验研究均表明所提出的方法是可行的。
关键词 光擦除 双光束耦合 多级探测 微弱光
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NOVEL DECODING OF SQUARE QAM MODULATED MIMO SYSTEMS BASED ON TURBO MULTIUSER DETECTION
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作者 Zheng Jianping Bai Baoming Wang Xinmei 《Journal of Electronics(China)》 2008年第2期174-178,共5页
By introducing the bit-level multi-stream coded Layered Space-Time (LST) transmitter along with a novel iterative MultiStage Decoding (MSD) at the receiver, the paper shows how to achieve the near-capacity perform... By introducing the bit-level multi-stream coded Layered Space-Time (LST) transmitter along with a novel iterative MultiStage Decoding (MSD) at the receiver, the paper shows how to achieve the near-capacity performance of the Multiple-Input Multiple-Output (MIMO) systems with square Quadrature Amplitude Modulation (QAM). In the proposed iterative MSD scheme, the detection at each stage is equivalent to multiuser detection of synchronous Code Division Multiple Access (CDMA) multiuser systems with the aid of the binary representation of the transmitted symbols. Therefore, the optimal Soft-Input Soft-Output (SISO) multiuser detection and low-complexity SISO multiuser detection can be utilized herein. And the proposed scheme with low-complexity SISO multiuser detection has polynomial complexity in the number of transmit antennas M, the number of receive antennas N, and the number of bits per constellation point Me. Simulation results demonstrate that the proposed scheme has similar Bit Error Rate (BER) performance to that of the known Iterative Tree Search (ITS) detection. 展开更多
关键词 Multiple-Input Multiple-Output (MIMO) MultiStage Decoding (MSD) Iterative detection/decoding Multiuser detection Polynomial complexity
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A graph based system for multi-stage attacks recognition
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作者 Safaa O.Al-Mamory 《High Technology Letters》 EI CAS 2008年第2期167-173,共7页
Building attack scenario is one of the most important aspects in network security.This paper pro-posed a system which collects intrusion alerts,clusters them as sub-attacks using alerts abstraction,ag-gregates the sim... Building attack scenario is one of the most important aspects in network security.This paper pro-posed a system which collects intrusion alerts,clusters them as sub-attacks using alerts abstraction,ag-gregates the similar sub-attacks,and then correlates and generates correlation graphs.The scenarios wererepresented by alert classes instead of alerts themselves so as to reduce the required rules and have the a-bility of detecting new variations of attacks.The proposed system is capable of passing some of the missedattacks.To evaluate system effectiveness,it was tested with different datasets which contain multi-stepattacks.Compressed and easily understandable Correlation graphs which reflect attack scenarios were gen-erated.The proposed system can correlate related alerts,uncover the attack strategies,and detect newvariations of attacks. 展开更多
关键词 network security intrusion detection alert correlation attack graph SCENARIO clus-tering
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