Remote Targets Recognition Based on Adaptive Weighting Feature Dictionaries and Joint Sparse Representations

With the improvement in resolution, more and more useful information is contained in the space of remote sensing images, which makes the processing of remote sensing data become more complex, and it is easy to cause the curse of dimensionality and the poor recognition effect. In this paper, a remote target recognition approach named AJRC is proposed, which uses joint feature dictionary for sparse representation based on different feature information for adaptive weighting. Firstly, the features of the images are extracted to calculate the contribution weight of each eigenvalue in sparse representation, and each eigenvalue contribution weight is calculated in sparse representation. Through the adaptive method, the contribution ability of each feature value in sparse representation is strengthened, and new atoms are formed to construct feature dictionary, which makes the dictionary more discriminative. Then, the common features of each category image and the private features of a single image are extracted from the feature vector, and a joint dictionary is formed to represent the test image sparse and recognize the output of the target. Aiming at the problem that the target visual contrast difference, the low resolution and the rotation of the target with different angles, the experiment is carried out by different feature extraction methods. At the same time, we use the PCA method to reduce the feature dictionary in order to avoid dimensionality. Experiments show that compared with the existing SRC method and JSM method, this method has better recognition rate.     

海洋光学遥感器的辐射定标与数据真实性检验综述

遥感数据定量化应用遥感技术深入发展亟须解决的重要课题,对遥感器进行辐射定标,对遥感数据进行真实性检验的工作已在深入开展,本文介绍了国际关于定标／真实性检验的组织及分工概况,简要阐述了定标／真实性检验的概念与做法,着重讨论了与海洋光学遥感器有关的辐射定标／真实性检验,综述了国外在这方面的若干做法,并在我们工作的基础上提出了开展此项工作的几个关键问题及中能解决的途径。     

秋季太湖悬浮物高光谱估算模型

2004年10月,在太湖设置67个采样点,现场测量了水体遥感反射比、后向散射系数和辅助参数,实验室分析了水体的悬浮物浓度和水色要素吸收系数.本文在对遥感反射比光谱分析的基础上,比较了几种水体遥感反射比光谱估算悬浮物浓度的方法,结果发现广泛应用的带比值项的算法,虽然可以应用于太湖总悬浮物浓度估算,但是普遍存在相对误差较高的弱点.通过对光谱的分析,确定了750hm单波段算法的参数,并提出了利用近红外812nm波峰高度来估算水体悬浮物的方法.文中还详细阐述了为什么比值算法等在太湖水体悬浮物浓度估算中相对误差比较高,并解释了利用近红外估算精度高的原因,并指明以上算法在遥感应用中的优点和不足,以及现实水体(水质)遥感对现有遥感器配置和遥感算法的需求.     

Novel uniaxial concrete constitutive model considering bond-slip effect

A uniaxial concrete constitutive model considering the bond-slip effect is proposed and its finite element analysis (FEA) implementation on a fiber section     

湖泊水色遥感研究进展

从卫星传感器、大气校正、光学特性测量、生物光学模型及水体辐射传输、水质参数反演方法等方面,系统分析了湖泊水色遥感的发展现状.湖泊水体物质组份的复杂性以及卫星传感器与实际需求的矛盾决定了湖泊水色遥感的难度.目前湖泊水色遥感在一些关键问题上仍没有实质性进步,离水色遥感监测的业务化尚有一段距离.令人欣慰的是,卫星传感器以及水色遥感反演算法的不断发展和进步,让我们看到了胜利的曙光.     

内陆水质遥感不确定性：问题综述

内陆水质遥感是目前定量遥感领域的热点与难点,多种不确定性因素影响了内陆水质遥感的研究进展。较系统地总结了国内外近年来内陆水质遥感监测存在的突出问题与影响水质遥感监测精度的关键因素,具体从内陆水体光学特性的复杂性、大气校正的复杂性与水面反射光校正的不确定性、反演算法与生物光学模型的复杂性与区域性、现有传感器监测内陆水质在性能方面的局限性以及影响因素的复杂性与综合性几个方面进行了阐述,并指出了内陆水质遥感监测的研究重点与发展方向。     

Preliminary investigation of seismic damage to two steel space structures during the 2013 Lushan earthquake

Severe damage to steel space structures is rarely reported when compared to other structural systems damaged during past major earthquakes around the world.Two gymnasiums of steel space structures in downtown Lushan County that were damaged during the 2013 M7.0 Lushan earthquake in China were investigated and the observations are summarized in this paper.Typical damage to these two steel space structures ranges from moderate to severe.Moderate damage includes global buckling and dislocation of bolted connections of truss members,and inelastic elongation of anchor bolts and sliding of pedestal plates of supports.Severe damage includes member fracture caused by local buckling,and fracture failure of anchor bolts and welds.The distribution of structural damage to these two structures is described in detail and future research opportunities are suggested.     

Empirical ocean-color algorithms to retrieve chlorophyll-a, total suspended matter, and colored dissolved organic matter absorption coefficient in the Yellow and East China Seas

A bio-optical dataset collected during the 1998?C2007 period in the Yellow and East China Seas (YECS) was used to provide alternative empirical ocean-color algorithms in the retrieval of chlorophyll-a (Chl-a), total suspended matter (TSM), and colored dissolved organic matter (CDOM) absorption coefficients at 440 nm (ag₄₄₀). Assuming that remote-sensing reflectance (Rrs) could be retrieved accurately, empirical algorithms for T_Chl (regionally tuned Tassan??s Chl-a algorithm) in case-1 waters (T_Chl2i in case-2 waters), T_TSM (regionally tuned Tassan??s TSM algorithm), and T_ag440 or C_ag440 (regionally tuned Tassan??s or Carder??s ag₄₄₀ algorithm) were able to retrieve Chl-a, TSM, and ag₄₄₀ with uncertainties as high as 35, 46, and 35%, respectively. Applying the standard SeaWiFS Rrs, T_Chl was not viable in the eastern part of the YECS, which was associated with an inaccurate SeaWiFS Rrs retrieval because of improper atmospheric correction. T_Chl behaved better than other algorithms in the turbid case-2 waters, although overestimation was still observed. To retrieve more reliable Chl-a estimates with standard SeaWiFS Rrs in turbid water (a proxy for case-2 waters), we modified T_Chl for data with SeaWiFS normalized water-leaving radiance at 555 nm (nLw₅₅₅) > 2 mW cm^?2 ??m^?1 sr^?1 (T_Chl2s). Finally, with standard SeaWiFS Rrs, we recommend switching algorithms from T_Chl2s (for case-2 waters) to MOC_Chl (SeaWiFS-modified NASA OC4v4 standard algorithm for case-1 waters) for retrieving Chl-a, which resulted in uncertainties as high as 49%. To retrieve TSM and ag₄₄₀ using SeaWiFS Rrs, we recommend empirical algorithms for T_TSM (pre-SeaWiFS-modified form) and MT_ag440 or MC_ag440 (SeaWiFS Rrs-modified forms of T_ag440 or C_ag440). These could retrieve with uncertainties as high as 82 and 52%, respectively.     

车载X波段双线偏振多普勒天气雷达及其数据处理系统

文章介绍了车载X波段双线偏振多普勒天气雷达及其数据处理系统,并对其资料质量和应用问题进行了分析和讨论。该雷达采用的单发双收的工作机制,实现对Z_H、Z_(DR)、Φ_(DP)、K_(DP)、ρ_(HV)(0)以及L_(DR)等参数的探测。这些信息反映了云和降水粒子的范围、大小和运动变化等特征,是研究云和降水特别是灾害性天气的形成机制及其物理过程变化的有效工具。基于该雷达的数据处理系统是在利用这些测量参数的基础上,可以实现降水处理和降水粒子相态识别功能,为用户提供有效的气象服务。     

成熟勘探矿集区新一轮找矿：勘查战略创新及铜陵矿集区找矿实例

成熟勘探的矿集区非常有必要开展新一轮的找矿，但矿床模式的局限和大埋藏深度等困难制约了这些地区的预测性找矿发现。促进其预测性找矿发现的关键战略包括：勘查模型的创新、勘查技术的创新和各种信息的综合集成预测。勘查模型的创新必须包含基于地球动力学剖析的新成矿概念，动力学数值模拟是有效的创新手段之一；勘查技术创新的主要目的是加大探测深度和提高探测与解释的准确性，必须以详细可靠的地质资料为基础；综合信息集成是利用GIS和知识驱动及数据驱动的方法充分提取各种数据中的有用信息，集成为更加可靠的预测图。在这种思想的指导下，我们在铜陵凤凰山矿田进行了预测和勘查，并成功地发现了深部的隐伏矿床。