基于空谱特征稀疏表达的治安风险检测文献综述

文章指出治安风险是在一定地域范围内,由治安秩序紊乱导致安全损失的一种未来情景.当前科技飞速发展,治安形势的复杂程度前所未有,亟需运用新的技术新手段深化风险认识,提高对治安风险的感知能力.利用有效的高光谱遥感辅助技术手段,可以探索针对偏僻地区,以专业载荷为基础的遥感治安风险预测路线,为科技强警走出一条新路.     

基于欠定盲分离的多目标微多普勒特征提取

连续波雷达多目标回波中多种微多普勒特征分离问题采用独立成分分析方法实现,该方法在使用中存在较大局限性,要求待分离的微多普勒特征之间必须是统计独立的,且仅局限于恰定和超定的方程组求解问题。然而,在多目标雷达观测场景下,雷达接收的混叠回波的个数通常少于目标的个数,各目标的微多普勒特征可能存在相关性。为此,提出了一种基于欠定盲分离的多目标回波微多普勒特征分离方法。该方法可以从少数原始混叠回波中分离出多个目标的微多普勒特征,对待分离的微多普勒特征限制性弱。通过数值仿真,证实了该方法的可行性。     

基于压缩感知的SAR图像目标识别

提出一种基于压缩感知的合成孔径雷达图像目标识别方法,将目标识别问题转化为稀疏表示的近似求解问题。该方法利用测试样本在全体训练样本基下的稀疏性,实现样本间的近似稀疏表示。通过考察稀疏系数主要集中于样本真实类别之上的分布特性,研究了稀疏系数本身对目标类别具有的可区分能力,最后基于稀疏系数的分布特性设计分类算法完成目标识别。基于MSTAR数据中三类目标的实验证明,与目前已有的几种典型方法相比,该方法可以取得更高的识别率,是一种有效的合成孔径雷达图像目标识别方法。     

Near-field time-frequency localization method using sparse representation

This paper presents a novel near-field source localization method based on the time-frequency sparse model.Firstly,the method converts the time domain data of array output into time-frequency domain by time-frequency transform;then constructs sparse localization model by utilizing the specially selected time-frequency points,and finally the greedy algorithms are chosen to solve the sparse problem to localize the source.When the coherent sources exist,we propose an additional iterative selection procedure to improve the estimation performance.The proposed method is suitable for uncorrelated and coherent sources,moreover,the improved estimation accuracy and the robustness to low signal to noise ratio(SNR) are achieved.Simulations results verify the efficiency of the proposed algorithm.     

Word-Representation-Based Method for Extracting Organizational Events from Online Media

Online social media exhibit massive organizational event relevant messages, and the well categorized event information can be useful in many real-world applications. In this paper, we propose a research framework to extract high quality event information from massive online media data. The main contributions lie in two aspects: First, we present an event-extraction and event-categorization system for online media data; second, we present a novel approach for both discovering important event categories and classifying extracted events based on word representation and clustering model. Experimental results with real dataset show that the proposed framework is effective to extract high quality event information.     

一种信号稀疏表示及其在气象传真图增强中的应用

舰艇在进行鱼雷试验和作战使用过程中,需要以气象传真图作为鱼雷航行和作战的水文气象保障,如何使气象传真图更加清晰可读成为急需解决的现实问题。提出了一种基于信号稀疏表示的针对海上气象传真图增强的新方法。该方法以气象传真图底图和固定的气象符号作为字典函数,充分利用气象传真图的稀疏特性,采用匹配追踪算法进行气象传真图稀疏表示,并利用气象传真图的稀疏系数有效分离噪声。试验结果表明,在气象传真图增强中,该方法明显优于目前的图像增强方法。