多传感器远距离目标跟踪精度分析

该文主要研究了非线性系统中多传感器远距离目标跟踪问题,提出了分布的转换坐标卡尔曼滤波算法,给出了当多传感器不在同一位置时融合中心的状态估计组合公式。     

区间卡尔曼滤波算法在组合导航数据融合中的应用

传统卡尔曼滤波算法在系统参数不确切已知或随时间变化时无法直接应用。本文通过将参数变化的系统建立成区间模型,给出了一种处理系统参数不确定性的区间卡尔曼滤波算法,该算法运用一种较为简单的区间矩阵求逆方案,在统计最优性能及迭代形式方面与标准卡尔曼滤波算法相当,仿真验证了该算法在低成本INS/GPS组合导航数据融合中应用的可行性。     

多传感器多模型动态系统交互式数据融合估计的一种算法

基于多传感器多模型信息,给出了目标状态基于全局信息融合估计的一种新算法,并通过计算机仿真验证了这种算法的有效性。     

基于最优信息融合卡尔曼滤波的预测控制算法

针对噪声环境下的线性时不变系统,给出了基于最优信息融合卡尔曼滤波的预测控制算法.运用线性最小方差意义下的最优信息融合卡尔曼滤波方法获得状态估计,进而得到输出的N步超前预测值,最后通过最小化二次性能指标获得基于信息融合状态估计的控制输入.仿真实例验证了算法的有效性.     

多传感器粒子滤波融合跟踪算法

对于非线性非高斯环境中的多传感器分布式状态估计问题,提出了一种基于二阶中心差分粒子滤波方法的融合跟踪算法.通过对量测方程的非线性分析,利用粒子滤波器计算目标状态估计值,以在线自适应加权融合算法的方式得到系统最优估计.仿真结果表明,与采用扩展卡尔曼滤波的方法相比,该算法具有更高的估计精度.     

基于不确定度量化加权的CKF算法

针对传感器网络中每个传感器节点的邻接节点状态估计值不确定度不同的问题,提出一种基于不确定度量化加权的一致性卡尔曼滤波算法(CKF).该算法通过考虑节点度数对于传感器网络估计精度的影响,结合节点度数提出了一种衡量邻接节点状态估计值不确定度的量化函数,并把量化值作为该邻接节点与当前节点的状态估计值偏差的融合权重引入一致性协议中,利用优化后的一致性协议对传感器节点先验估计值进行更新,可提高一致性卡尔曼滤波算法的估计精度;算法同时具有非一致性误差小和鲁棒性强等特点.最后在3种不同网络类型下,通过动态目标跟踪实验仿真验证了算法的有效性.     

带有等式状态约束的多传感器数据融合算法

在状态估计理论的实际应用中,状态向量常常包含可以预先获知的约束信息,有效地利用这些先验信息可以进一步明确状态元素之间的关系,理论上可以提高对系统的状态估计精度.针对约束滤波的已有研究成果,将其引入到多传感器系统,提出了约束系统多传感器数据融合算法.通过建立线性等式约束方程,将传统卡尔曼滤波结果投影到约束子空间,然后对局部传感器的约束滤波结果采用分布式最优加权融合,并且通过协方差匹配技术检测观测数据异常的传感器,使之不参与到数据融合中.仿真结果表明,约束系统分布式加权融合算法的有效性和可行性,并且比集中式融合算法具有更好的稳定性.     

基于联合卡尔曼滤波的汽车防碰撞多传感器信息融合方法

车辆行驶信息感知是汽车防碰撞系统的关键技术之一,只用单一传感器对目标车辆进行测量容易产生虚警.在对联合卡尔曼滤波分析的基础上,给出了基于联合卡尔曼滤波的汽车防碰撞多传感器信息融合方法.计算机仿真结果表明,该算法可以得到较精确的融合数据,对于增强汽车防碰撞系统的安全性具有重要意义.     

基于动态加权下测量方差适应的同质多传感器融合算法

在基于卡尔曼滤波及其一些改进算法中,由于测量方差预先设定,从而导致信息资源的浪费和状态估计精度的下降,为此提出一种动态加权下测量方差自适应的同质多传感器融合算法．该算法依据各传感器当前时刻的滤波精度合理地分配权值,同时测量方差的时变特性,使得每次测量的信息得到充分的利用．仿真结果表明,该算法显著地提高了对机动目标的跟踪效果并具有实时性的优点。     

任意噪声相关异类传感器非线性系统状态矢量融合

基于线性无偏最小方差估计理论，提出了一种任意相关噪声异类传感器非线性系统状态矢量融合算法．该算法考虑了过程噪声和测量噪声以及测量噪声之间的相关性和传感器系统结构的不同性，增加了描述多传感器融合系统的信息量，通过局部估计的组合构造新的变量以去除局部状态之间的相关性，采用顺序滤波的方法减小了异类多传感器融合系统全局状态估计的计算量．仿真结果表明，由于考虑了过程噪声和测量噪声以及测量噪声之间的相关性，状态矢量融合算法比噪声不相关融合算法具有更好的跟踪性能，航迹跟踪的精度得到了改善．     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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