共查询到20条相似文献,搜索用时 78 毫秒
1.
2.
3.
该文研究了非均匀环境中的分布目标和多点目标的检测。其中,假设辅数据协方差矩阵服从以主数据协方差矩阵为条件的逆Wishart分布,且均值与之成比例。首先给出主数据协方差矩阵、比例因子和目标幅度的最大似然估计(MLE),然后基于贝叶斯理论和广义似然比(GLRT)判决准则提出了一种检测器。当目标只存在单个距离门时,检测器和自适应相干估计器(ACE)一致;当目标跨越多个距离门时,检测器和广义自适应子空间检测器(GASD)一致。但不同在于ACE和GASD都是基于未知的确定干扰协方差矩阵的。另外,该检测器具有恒虚警率(CFAR)特性,并且有很好的检测性能。 相似文献
4.
5.
6.
7.
红外焦平面阵列剩余非均匀性的计算 总被引:5,自引:1,他引:5
从理论、计算方法和计算结果等方面分析了已有的三种剩余非均匀性(即剩余误差)计算方法的不足,根据探测器非线性响应原理,提出了一种新的方法。以实验数据对有关方法进行了验证,结果表明新的方法更为简单且更符合实际。与以前理论比较,推导出了近似公式。 相似文献
8.
分析了红外焦平面阵列(IRFPA)基于定标的非均匀性校正算法和基于场景的非均匀性校正算法的优势和不足。针对红外焦平面阵列二元非线性的非均匀性理论模型这一特点,提出了一种基于S曲线拟合的校正算法。利用FLIR公司的长波非制冷红外探测器进行信号采集,建立了焦平面探测元的响应模型。描述了基于FLIR长波非制冷红外探测器在FPGA平台的处理流程,并实现了S曲线校正算法,提高了红外图像的质量。实验表明,经过S曲线拟合校正处理,减弱了红外图像的条纹噪声,使IRFPA组件的非均匀性从6.45%降低至2.06%。 相似文献
9.
非均匀介质中的孤子和孤波对于相对论量子力学和量子电子学(例如红外孤子激光器的研究)是很有意义的。本文在简单介绍孤子的数学方法之后,根据由折射率和非谐势函数修正的非线性Klein-Gordon方程,对非均匀一维非线性介质中的孤子和孤波进行了理论研究,特别强调了周期调制的情况。并采用了不同的近似运算求解孤波和孤子,将算得的典型解绘制成图,以直观地说明孤子和孤波的特征。 相似文献
10.
基于黑体标定的非均匀性校正方法在凝视红外成像系统中被广泛应用,但在面对天空背景成像或者高速飞行器上透过高温光学窗口观察常温目标两种情况下,出现了黑体标定不适用的现象。为此通过分析红外成像系统的响应特性,提出了响应光谱非均匀性的概念,指出了黑体标定法具有场景光谱分布依赖的特征。同时,分析了响应光谱非均匀性产生的原理,包括内外两方面原因。内在因素是红外探测器不同像元的量子效率随光谱变化存在差异,外在因素是应用场景的辐射光谱分布与黑体相差较大。在此基础上,给出了解决响应光谱非均匀性的建议。 相似文献
11.
提出了一种基于主动探测的eMule行为监测方法,并设计和实现了一个eMule行为监测系统.系统测试表明,本系统能够对eMule行为进行有效地监测,并获取eMule客户端特征信息,为eMule行为监管提供了有效的技术手段. 相似文献
12.
运动目标的跟踪打击需要情报部门实时接收多源信息,同时目标信息的订阅部门也需要在有限时间内从情报部门订阅并快速获取此类信息。这些信息包括实时变化的遥感图像、坐标位置等各类参数数据,数据量大、分类繁多,而各类信息的使用部门所应用的系统技术体制、数据格式及传输方式也不尽相同。文中提出一种基于栅格和P2P网络分发拓扑结构下,设立情报部门统一的信息分发系统。使用OWL—S语言对获取的多源目标信息进行语义分类描述和本体建模,通过多Agent协同进行兴趣识别、语义推理和信息匹配过滤,最终通过判断负载均衡进行路由选择,以满足大规模订阅需求的信息同步分发。 相似文献
13.
几乎所有多目标进化算法(multi-objective optimization evolutionary algorithm,MOEA)都是针对Pareto最优面为均匀分布问题而言.然而现实中很多问题Pareto最优面是非均匀分布的,决策者希望得到一个与Pareto最优面分布类似的解集.现存算法并不能有效解决该问题.对此,提出一种针对于非均匀分布多目标优化问题的维护方法(non-uniformly diversity maintenance method,NUDMM).该方法定义一个反映个体分布"规则"程度的指标——杂乱度,并设计一种降低种群杂乱度的方法,在未知Pareto最优面分布规律情况下有效剔除造成种群混乱的个体.通过与NSGA-II和SPEA2在不同维数下8个非均匀函数上对比实验,表明NUDMM在有效保持问题真实分布的同时,具有良好的收敛性. 相似文献
14.
少数载流子寿命横向非均匀分布的快恢复二极管特性 总被引:1,自引:1,他引:1
提出了一种快恢复二极管新结构:少数载流子寿命横向非均匀分布(m inority- carrier life tim e lateral non- u-niform distribution,ML D)结构.利用普通的p+ nn+ 二极管芯片,通过掩蔽扩散选择性地掺入深能级杂质,制备出了掺Au、Pt的ML D快恢复二极管.测试结果表明,虽然这种快恢复二极管正向压降-反恢时间兼容特性略差,且反向漏电流较大,但是具有十分良好的反恢时间-温度的稳定特性,可以用于对反恢时间变化要求严格的领域. 相似文献
15.
16.
Yingsong Li Chaozhu Zhang Shigang Wang 《Circuits, Systems, and Signal Processing》2016,35(5):1611-1624
In this paper, an improved sparse-aware affine projection (AP) algorithm for sparse system identification is proposed and investigated. The proposed sparse AP algorithm is realized by integrating a non-uniform norm constraint into the cost function of the conventional AP algorithm, which can provide a zero attracting on the filter coefficients according to the value of each filter coefficient. Low complexity is obtained by using a linear function instead of the reweighting term in the modified AP algorithm to further improve the performance of the proposed sparse AP algorithm. The simulation results demonstrate that the proposed sparse AP algorithm outperforms the conventional AP and previously reported sparse-aware AP algorithms in terms of both convergence speed and steady-state error when the system is sparse. 相似文献
17.
Hamed Alizadeh Ghazijahani Mir Javad Musevi Niya 《Wireless Personal Communications》2018,98(2):1753-1770
Recently, visible light communication (VLC) has got increasing attention in the field of indoor wireless communications. VLC has the obligation of lighting besides data communications. The IEEE 802.15.7 task group proposed a VLC modulation format named color shift keying in which data symbols are defined based on the diffused light wavelength. This paper presents a new modulation scheme for indoor wireless visible light communication system named non-uniform time slot modulation (NUTS). The NUTS modulation scheme defines the feeder signals of red, green and blue LEDs as rectangular pulses with appropriate width and their positions. In this method, the time axes of all the three light sources (channels) are slotted to some non-uniform durations that all symbols are spanned over these slots as orthogonal dimensions. The proposed scheme has some advantages with respect to other approaches such as low bit error rate and high bit rate. Furthermore, it provides appropriate synchronization capability. Besides, in the design of NUTS modulation scheme it has been tried to deliberate all practical constraints, as far as possible. 相似文献
18.
从智能大楼的概念出发,分析了智能大楼的特点及传统的配线方式存在的问题,结合国内外智能大楼的发展,介绍了一种新的综合布线系统。 相似文献
19.
An evolution model of KAD Dynamic Model Network (KDMN) is proposed to study the reason of hot node and simulate the process of network evolution based on node behavior from a holistic perspective. First, some symbols and meanings are introduced to describe nodes relationship and network states at a time step. Second, some evolution rules for network are formulated when node behaviors of join, exit, routing table update, data retrieval and content index distribution happen with different contextual scene in KAD network. In addition, a lightweight simulator is designed to implement the KDMN model. Moreover, an example of how to use the simulator to simulate the network changes in order to observe the result is described in detail. Finally, the KDMN is applied to analyze the reason for the formation of hot nodes in the BT and eMule network in the experiment. The different evolution principles of local priority, global priority and hybrid random are adopted based on the provision of network protocol of BT and eMule. The result of this experiment demonstrates that there are some hot nodes exist in the KAD network. However, the principle of hybrid random can effectively alleviate the phenomenon that a node is widely linked with others compared with global and local priority. 相似文献