多扩展目标的高斯混合概率假设密度滤波器

针对多扩展目标跟踪中状态信息难以估计的问题,提出了一种可以估计扩展目标运动状态和形状信息的多扩展目标高斯混合概率假设密度(RHM-GMPHD)滤波器。首先利用描述凸星形扩展目标量测源分布的随机超曲面模型和传感器量测方程,建立扩展目标运动状态及形状信息与量测之间关系的伪量测函数;然后结合扩展目标状态预报信息,推导了扩展目标状态更新方程,递推地对扩展目标运动状态及形状信息进行估计跟踪。此外,还建立了Jaccard距离来度量RHMGMPHD滤波器对目标形状的估计性能。与联合概率数据关联(JPDA)滤波器和GMPHD滤波器相比,RHM-GMPHD滤波器不仅可以估计凸星形扩展目标的形状信息,并能有效提高对目标数和运动状态的估计精度。仿真实验表明,RHM-GMPHD滤波器对质心估计的均方根误差分别约为JPDA和GMPHD滤波器的1/3和1/2,对目标数的估计接近真实值,对形状估计的Jaccard距离一般小于0.2。     

基于箱粒子滤波的扩展目标伯努利跟踪算法

针对复杂环境下,扩展目标跟踪量测存在漏检以及量测不精确、模糊的问题,引入区间分析技术,提出了一种基于箱粒子滤波的扩展目标伯努利滤波算法.算法首先采用伯努利随机有限集和泊松随机有限集分别描述扩展目标的状态和观测,然后将箱粒子滤波应用到扩展目标伯努利滤波算法,推导了适用于不确定量测的扩展目标伪似然函数和状态更新方程,并用伯努利箱粒子滤波递推地对扩展目标的状态进行估计跟踪.仿真实验表明:与扩展目标伯努利粒子滤波算法相比,所提算法在保证扩展目标跟踪性能的同时,有效减少了算法的计算时间.     

基于随机有限集理论的多扩展目标跟踪技术综述

随着传感器分辨率的不断提高,扩展目标跟踪技术在实际应用中的作用日益凸显。传统的基于数据关联的目标跟踪方法在对多扩展目标进行跟踪时难以适用,而基于随机有限集理论的方法由于避免了数据关联的困扰而得到了广泛的关注和大量的研究。通过对近年来基于随机有限集理论的多扩展目标跟踪技术研究现状进行了综合分析,包括外形建模方法、最优多目标跟踪贝叶斯滤波器的各类近似技术以及基于随机有限集的多扩展目标跟踪算法的性能评价指标等。最后在已有研究发展的基础上,提出了基于随机有限集理论的多扩展目标跟踪技术需重点关注和解决的若干问题,包括如何将外形建模与群目标轮廓建模进行结合、多机动扩展目标跟踪、多扩展目标跟踪性能评价指标、非线性非高斯下的扩展目标跟踪、非标准量测下的扩展目标跟踪等问题。     

采用随机矩阵的多扩展目标滤波器

针对杂波环境下多扩展目标的运动状态和形状信息的联合估计跟踪的问题,提出了一种基于随机矩阵的扩展目标跟踪算法。该算法采用具有噪声基于密度的空间聚类(DBSCAN)划分与预测划分相结合的联合划分算法对量测集进行划分,然后采用联合概率数据关联(JPDA)的软关联思想建立量测簇与扩展目标之间的对应关系,最后采用随机矩阵法对扩展目标进行估计获得运动状态和形状信息,特点是:将量测集划分为互不相交的几个簇,以使每个簇中的量测源于同一目标或杂波;建立量测簇与扩展目标之间的关联关系及状态更新。联合划分算法与DBSCAN划分的比较仿真实验表明,在有距离相近目标时采用联合划分算法比采用DBSCAN划分的滤波器的跟踪效果好得多。所提多扩展目标滤波器与ET-GMPDH滤波器的仿真实验表明,所提算法有较高的跟踪精度、较大的检测概率及较小的虚警概率。     

基于椭圆RHM的扩展目标伯努利滤波算法

针对扩展目标跟踪中存在的扩展状态估计不准确和非线性问题,提出一种基于随机超曲面模型(RHM)的扩展目标伯努利滤波算法.首先采用RHM对目标量测源建模,然后在扩展目标伯努利滤波框架下,实现对单扩展目标运动状态和扩展状态的实时估计,最后引入Gamma分布以提高量测率估计的准确性.为了降低计算复杂度,在量测更新中采用距离划分来减少所有可能的划分总数.仿真结果表明,所提滤波算法在估计目标运动状态、扩展状态和量测率等方面优于单目标伯努利滤波算法.     

非线性多模型多伯努利滤波器的实现

针对杂波、漏检等环境下的多机动目标估计问题,提出了两种非线性系统模型下多模型多伯努利(MM-MB)滤波器的实现方法.首先,基于容积卡尔曼滤波算法给出了MM-MB滤波器的容积卡尔曼高斯混合(CK-GM)实现过程;然后,为了增加CK-GM-MM-MB滤波算法的数值稳定性,给出了MM-MB滤波器的平方根容积卡尔曼高斯混合实现过程;最后,通过仿真实验验证了所提方法的有效性.     

箱粒子广义标签多伯努利滤波的目标跟踪算法

针对序列蒙特卡罗广义标签多伯努利滤波(SMC-GLMB)算法计算效率低、实时性差的问题,提出了箱粒子广义标签多伯努利滤波的目标跟踪(Box-GLMB)算法。该算法使用带标签的随机有限集描述多目标的状态,包括目标的位置和速度,并且对每个目标用互不相同的标签进行区分;然后利用箱粒子滤波算法近似单目标状态的概率密度,即用一组带权值的均匀分布拟合单目标状态概率密度;最后通过广义标签多伯努利滤波对多目标状态的概率密度进行预测与更新,从多目标状态后验概率密度中估计单目标的位置与速度,根据目标的标签可以实现航迹跟踪。BoxGLMB算法结合了箱粒子滤波与GLMB算法的优势,能够跟踪目标航迹,同时提高计算效率。仿真结果表明,Box-GLMB算法可以有效估计目标状态以及跟踪目标航迹,相比于SMC-GLMB算法,计算效率提升了62%。     

高斯混合标签多伯努利滤波器的传感器控制策略

针对多目标跟踪优化中的传感器控制问题,提出一种基于高斯混合标签多伯努利滤波器的快速传感器控制策略,并将其用于基于目标威胁度评估的风险评估中.首先,给出高斯混合标签多伯努利滤波器的实现形式,并对两个高斯混合之间的柯西施瓦兹散度求解.其次,利用多伯努利部分替代传感器控制中标签多伯努利伪更新步骤,即在多伯努利更新过程中采用了...     

基于贪婪量测划分的隐身目标跟踪MS-LMB滤波器

针对隐身目标的跟踪,本文将贪婪量测划分的方法应用于多传感器标签多伯努利(MS-LMB)滤波器中,较好地解决了低检测概率下的多雷达跟踪问题. 传统的MS-LMB滤波器一般采用吉布斯采样来解决量测划分问题. 当雷达网中多数雷达对隐身目标的检测概率较低而处于漏检状态时,目标的似然权值将偏小而很难被吉布斯采样获取,从而难以准确估计隐身目标的状态. 贪婪量测划分机制由于单独考虑了包含漏检项的量测集,可有效解决此问题. 仿真实验结果表明,在隐身目标的跟踪中,采用贪婪量测划分的MS-LMB滤波器的滤波性能明显优于采用吉布斯采样的MS-LMB滤波器的性能.      

标签多伯努利机动目标跟踪与分类算法

针对密集杂波下现有的多机动目标跟踪算法性能衰减严重的问题,提出了一种标签多伯努利目标跟踪与分类算法。首先,引入类别信息对目标状态进行扩维;然后利用类别属性对目标机动模型转移密度进行修正,并推导新的状态转移密度函数,抑制了错误机动模型对目标状态预测的影响;同时,建立目标位置与属性的联合量测似然函数,增大了目标与杂波的区分度,从而增强杂波抑制能力;最后,基于多模型标签多伯努利滤波器框架推导了新的预测、更新方程。仿真实验结果表明:所提算法在高杂波环境下仍能对多机动目标进行有效跟踪,其目标数估计误差及最优子模式分配距离分别约为多模型概率假设密度联合检测、跟踪、分类滤波器的1/2和1/4,为多模型势平衡多伯努利联合检测、跟踪、分类滤波器的3/4和1/2。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has