拓展目标量测集合分割算法

针对拓展目标概率假设密度滤波器采用的量测集合所有可能分割方式在实际中几乎不能够实现的问题,提出了一种采用有限混合模型的量测集合近似分割算法,对所有可能分割方式进行近似处理。算法利用有限混合模型拟合量测集合以实现对量测集合的分割,首先利用期望极大化算法极大似然估计混合参数,然后利用量测来源的条件概率分割量测集合,最后以二维场景为例进行了仿真实验。仿真结果表明:新算法在所有时刻上的最优子模式分配和混合分量数目均小于现有的典型量测集合分割算法;在拓展目标跟踪性能上,新算法具有更好的多拓展目标跟踪性能。     

拓展目标混合分量删减算法

针对拓展目标概率假设密度滤波器高斯混合实现中的混合分量增长问题,提出混合分量的极大似然删减算法.该算法利用期望极大化方法实现混合分量的极大似然删减;视量测在混合分量的来源指标集为缺失量;取混合参数的先验分布为依赖于混合权重的分布;在期望步,计算量测在混合分量来源指标的条件概率;在极大化步,通过混合权重置零来实现相关度较小混合分量的删减.仿真结果表明,该混合分量极大似然删减算法优于典型阈值删减算法.     

基于噪声方差估计的高斯混合概率假设密度滤波算法

针对传统的高斯混合概率假设密度(GM-PHD)滤波器在噪声先验特性未知或不准确时跟踪性能会下降,提出了一种基于噪声方差估计的高斯混合概率假设密度(NCE-GM-PHD)滤波算法.该算法可以同时在线估计时变的目标个数、多目标状态以及噪声方差.首先,通过引入遗忘因子和采取有偏估计的方法改进了传统的Sage-Husa自适应滤波器.基于改进的自适应滤波器,推导了带噪声方差估计的GM-PHD滤波算法.仿真结果表明,在非时变或时变量测噪声方差未知的情况下,NCE-GM-PHD算法的跟踪性能优于传统的GM-PHD算法,对噪声变化的适应能力更强.     

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。     

高斯混合扩展目标多伯努利滤波器

针对杂波环境下多扩展目标跟踪中数据关联过程复杂的问题,提出一种可同时估计扩展目标状态和目标数的高斯混合扩展目标多伯努利(GM-ET-MBer)滤波器,该滤波器无需对测量与扩展目标进行关联。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;然后结合扩展目标状态的预测信息,推导了扩展目标状态的更新方程,并在线性高斯条件下采用高斯混合方法递推地对扩展目标的状态进行估计跟踪。与高斯混合扩展目标概率假设密度(GM-ET-PHD)滤波器相比,GM-ET-MBer滤波器有效地提高了对目标数的估计精度。仿真结果表明,GM-ET-MBer滤波器和GM-ET-PHD滤波器对目标数估计的标准偏差分别为0.267 3和0.395 3,可知所提滤波器对目标数的估计更稳定。     

多个不可分辨目标群的联合检测与估计误差界

针对杂波和漏检同时存在时多个不可分辨目标群联合检测与估计的性能评价问题,在随机有限集框架下,利用信息不等式和最优子模式分配距离提出了该问题的误差(下)界。首先将多个不可分辨目标群的状态建模为多Bernoulli随机有限集,并利用Mahler提出的连续个体目标数假设建模群目标测量似然函数;然后,结合最大后验概率检测和无偏估计准则获得了建议的误差界。仿真实验展示了该误差界随杂波密度和传感器检测概率的变化趋势,并利用不可分辨目标群势概率假设密度滤波器和不可分辨目标群势平衡多目标多Bernoulli滤波器对该误差界的有效性进行了验证。实验表明,利用该误差界可以对现有的不可分辨目标群联合检测与估计算法的性能进行有效衡量,使其在不同杂波密度和检测概率下的平均相对误差不超过7%。     

应用Dirichlet分布的概率假设密度多目标跟踪

针对多目标跟踪算法对多目标状态提取的需求,提出了一种基于Dirichlet分布的概率假设密度滤波器多目标状态提取方法.该算法利用负指数Dirichlet分布的不稳定性来极大似然估计多目标状态;利用期望极大化算法搜寻极大似然解,同时利用Dirichlet分布驱使不相关分量消亡;为了平衡成功初始化与减少算法时间开销的要求,利用k-d树初始化Dirichlet分布.仿真结果表明,基于Dirichlet分布的概率假设密度滤波器多目标状态提取算法在多目标跟踪中优于已有算法.     

一种改进的高斯混合概率假设密度滤波器

针对近邻目标场景下高斯混合概率假设密度滤波器的滤波精度较差问题,该文提出一种改进的高斯混合概率假设密度滤波器。基于更新后的目标强度中目标身份信息,首先将近似同一目标的多个高斯分量融合为一个新的高斯分量,然后依据目标检测结果对各目标分量的权重进行重新分配以获取一个精确的后验强度。实验结果表明,与相关近邻目标GM-PHD滤波器相比,该文算法的目标状态及数目估计精度具有较大优势,且其滤波性能相对稳定。     

一种新的多机动目标跟踪的GMPHD滤波算法

针对多机动目标跟踪的传统数据关联算法约束条件苛刻、估计精度低、计算量大等问题,提出了一种基于随机集理论的非数据关联的多机动目标跟踪算法.该算法将高斯混合概率假设密度(GMPHD)滤波与"当前"统计模型的优点相结合,绕过了棘手的数据关联问题,能高效处理目标数较大的机动跟踪问题.在漏检、虚警、多机动目标交叉杂波复杂环境下进行了仿真实验,结果表明,该算法具有较高的跟踪精度和稳健的跟踪性能.     

基于容积原则的概率假设密度滤波算法

为改善多目标跟踪问题中概率假设密度滤波精度与算法运行时间之间的关系,提高目标状态和数目的实时估计性能,提出了基于容积原则的概率假设密度滤波算法. 该算法在高斯混合粒子概率假设密度的框架下,利用容积数值积分原则直接计算非线性随机函数的均值和方差, 产生粒子滤波算法的重要性函数,实现高精度粒子的重构,来近似目标状态和数目的概率分布,并且在高斯混合概率假设密度滤波算法中进行采样和更新. 仿真验证了所提出算法的有效性,其Wasserstein误差距离优化了17.32%,目标数估计均值也提高了23.72%.      

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.     

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.     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

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.     

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.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

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。     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

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.