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基于杂波量测集约束的改进MS-MeMBer滤波器 被引量:1
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作者 陆小科 张志国 +1 位作者 孙进平 孙伟 《北京航空航天大学学报》 EI CAS CSCD 北大核心 2021年第9期1748-1755,共8页
针对高杂波密度场景下,传统多传感器多目标多伯努利(MS-MeMBer)滤波器存在的量测划分假设质量下降、势估计结果出现偏差等问题,提出了一种基于杂波量测集约束的改进MS-MeMBer滤波器。首先,通过将杂波量测集的影响引入到更新过程中,优化... 针对高杂波密度场景下,传统多传感器多目标多伯努利(MS-MeMBer)滤波器存在的量测划分假设质量下降、势估计结果出现偏差等问题,提出了一种基于杂波量测集约束的改进MS-MeMBer滤波器。首先,通过将杂波量测集的影响引入到更新过程中,优化了目标量测集的权重,并给出了杂波场景下的单目标多传感器似然函数。然后,通过两步贪婪划分机制,得到了改进的多传感器量测划分假设。通过仿真将所提方法与传统MS-MeMBer滤波器进行了比较,实验结果表明:在高杂波密度场景下,改进MS-MeMBer滤波器具有更优的多目标跟踪性能。 展开更多
关键词 多目标跟踪 多传感器多目标多伯努利(MS-MeMBer)滤波器 杂波测集 测划分假设 高杂波密度
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基于贪婪量测划分的隐身目标跟踪MS-LMB滤波器
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作者 孙进平 代贝宁 张玉涛 《北京理工大学学报》 EI CAS CSCD 北大核心 2022年第12期1290-1298,共9页
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... 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. 展开更多
关键词 隐身目标跟踪 多传感器多目标跟踪 MS-LMB滤波器 测划分假设
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科学假设,有效提升高中化学解题效率
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作者 石红炽 《学苑教育》 2018年第20期74-74,共1页
科学假设不管是在科学研究中还是在一般的教学实践及学习中都被普遍运用.在学生习题解题过程中, 科学假设能够开发拓展学生的思维能力, 起到一定的导向作用,有效地提升解题效率.
关键词 极端假设 等效假设 参照假设
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相控阵雷达自适应目标跟踪算法的比较
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作者 M.穆努 王俊仪 《指挥控制与仿真》 1994年第1期42-53,共12页
本文介绍和比较了把时变更新时间引入三种基于αβ和αβγ滤波器的目标跟踪算法的效果。介绍了由此产生的性能指标,这些性能指标包括均方误差、平均更新时间和平均更新次数。更新次数是根据位置残差的平方根或立方根的倒数选择的。不... 本文介绍和比较了把时变更新时间引入三种基于αβ和αβγ滤波器的目标跟踪算法的效果。介绍了由此产生的性能指标,这些性能指标包括均方误差、平均更新时间和平均更新次数。更新次数是根据位置残差的平方根或立方根的倒数选择的。不出所料,在机动期间,αβγ滤波器产生的更新次数比由αβ滤波器获得的更新次数多,而在机动期间,用前者获得的残差较小。我们发现:当使用αβ滤波器时,根据残差平方根的倒数和当使用αβγ滤波器时根据残差立方根的倒数选择更新时间时,获得了更新次数和估计误差之间最好的兼顾。最后讨论了αβ和αβγ滤波器怎样结合才能跟踪机动目标。 展开更多
关键词 相控阵雷达 目标跟踪算法 机动目标 性能指标 更新时间 估计误差 均方误差 目标航迹 最佳估计 假设量
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一种改进的定时同步算法 被引量:2
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作者 朱峰芹 翟旭平 +1 位作者 田朝阳 张小东 《电子测量技术》 2016年第2期42-45,共4页
离散傅立叶变化扩展的正交频分复用(DFT-S-OFDM)技术已被3GPP采用,作为长期演进项目(LTE)的上行调制方案,具有峰均比(PAPR)低等优势。该方案中接收机端现有的定时同步算法,大都不能适应低信噪比的高斯白噪声信道和多径衰落信道的恶劣环... 离散傅立叶变化扩展的正交频分复用(DFT-S-OFDM)技术已被3GPP采用,作为长期演进项目(LTE)的上行调制方案,具有峰均比(PAPR)低等优势。该方案中接收机端现有的定时同步算法,大都不能适应低信噪比的高斯白噪声信道和多径衰落信道的恶劣环境。针对此情况,本文提出了一种改进的假设检验统计量,用来进行定时同步。理论分析与仿真表明,在AWGN信道和多径衰落信道下,低信噪比(-10dB)的工作条件,改进的算法对高速运动引起的多普勒频偏具有较强的抵抗力。接收机能快速、高准确率的同步上发送数据的帧头,改进算法对工程应用具有一定价值。 展开更多
关键词 DFT-S-OFDM 定时同步 假设检验统计 多普勒频偏
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Comparing the Effects of Different Post-Listening Output Tasks on Second Language Incidental Vocabulary Acquisition:Revisiting the Involvement Load Hypothesis 被引量:1
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作者 Le CHANG Yumeng DING 《Chinese Journal of Applied Linguistics》 2021年第4期506-519,590,共15页
Based on the Involvement Load Hypothesis, the present study investigated the differential effects of three post-listening output tasks(gap-filling, translation, and sentence-making) on immediate acquisition and retent... Based on the Involvement Load Hypothesis, the present study investigated the differential effects of three post-listening output tasks(gap-filling, translation, and sentence-making) on immediate acquisition and retention of such vocabulary dimensions as productive knowledge of orthography,receptive recall of meaning and form, and productive knowledge of grammatical functions. Ninety second-year English majors were divided into three groups to finish listening plus one of the postlistening tasks. The results showed that the post-listening output tasks had positive effects on immediate acquisition of productive vocabulary knowledge, partially in agreement with the Involvement Load Hypothesis. However, the effects on vocabulary knowledge retention were found to be largely inconsistent with the Involvement Load Hypothesis. The finding thus challenges this hypothesis in that involvement load is not the only determining factor and suggests that the theoretical construct of involvement load should be constructed with more caution. 展开更多
关键词 incidental vocabulary acquisition Involvement Load Hypothesis LISTENING output tasks
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Simplified Scheme for Testing Symmetrization Postulate for Photons
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作者 YE Sai-Yun 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第5期913-915,共3页
We propose a scheme for testing the small violations of the symmetrization postulate (SP) for photons in cavity QED. In the scheme, a degenerate A-type three-level atom is sent through a cavity field initially in a ... We propose a scheme for testing the small violations of the symmetrization postulate (SP) for photons in cavity QED. In the scheme, a degenerate A-type three-level atom is sent through a cavity field initially in a q-deformed coherent state. After an appropriate interaction time, the atom is measured by a state-selective detector. The probability that the atom makes a transition from one of the lower states to the other characterizes the violation of the SP. In the scheme, only one atom is required and classical fields are unnecessary, which is prior to the previous schemes. 展开更多
关键词 symmetrization postulate PHOTON Raman interaction
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两种高考选考科目计分方法对比研究
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作者 刘慧 《教育测量与评价》 2020年第10期19-25,54,共8页
在新一轮高考综合改革中,不少省份采用科目内标准化方法对选考科目进行计分。由于各科目选考考生来自不同总体,这种计分方法可能给选考科目分数带来误导性的、表面上的可比性。对基于假设总体的量表化方法在选考科目分数量尺调整上的效... 在新一轮高考综合改革中,不少省份采用科目内标准化方法对选考科目进行计分。由于各科目选考考生来自不同总体,这种计分方法可能给选考科目分数带来误导性的、表面上的可比性。对基于假设总体的量表化方法在选考科目分数量尺调整上的效果进行了研究,同时与科目内标准化方法进行对比,结果表明:采用基于假设总体的量表化方法,以统考科目作为锚测验对选考科目成绩进行调整,能够大幅降低选考科目计分上的偏差。 展开更多
关键词 高考综合改革 选考科目计分 科目内标准化方法 基于假设总体的表化方法
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预应力钢筒混凝土管(PCCP)为什么不做出厂水压试验?——PCCP保护层裂缝的校核和验证
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作者 沈之基 《城镇供水》 2019年第1期24-29,49,共7页
经受不起出厂水压试验的PCCP,在"保护层裂缝校核验算程序"的包装下,以"高工压大口径最优选择"的优势走向世界。这个校核验算程序是未经过验证的错误假设, PCCP结构变形规律原型试验,验证了这个假设是错误的并已公... 经受不起出厂水压试验的PCCP,在"保护层裂缝校核验算程序"的包装下,以"高工压大口径最优选择"的优势走向世界。这个校核验算程序是未经过验证的错误假设, PCCP结构变形规律原型试验,验证了这个假设是错误的并已公开公布,中国PCCP行业一定会有积极的响应和行动,中国PCCP从此将回归真实,进入健康发展之路。管道用户要抓紧盘点自己的PCCP资产,哪些是安全的?哪些是高风险的?将精力和资源集中用在高风险的管道。 展开更多
关键词 水压试验 保护层 裂缝 微裂缝 可见裂缝 有害裂缝 变形假设
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阅读中影响二语词汇附带习得的因素
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作者 韩婷 《纳税》 2017年第14期168-168,171,共2页
二语词汇的附带习得是指学习者在进行有意义的第二语言学习活动和完成任务中,注意力并不在词汇上,却附带地增加了词汇知识,是一种注意力聚焦于其他活动时顺便出现的认知活动。阅读是进行二语词汇的附带习得的主要方式。本文对阅读中影... 二语词汇的附带习得是指学习者在进行有意义的第二语言学习活动和完成任务中,注意力并不在词汇上,却附带地增加了词汇知识,是一种注意力聚焦于其他活动时顺便出现的认知活动。阅读是进行二语词汇的附带习得的主要方式。本文对阅读中影响二语词汇附带习得的因素和如何设计增强词汇附带习得效果的任务进行了详细的阐述,并为二语词汇附带习得实践提供相关指导。 展开更多
关键词 二语词汇附带习得 学习者因素 篇章因素 投入检验假设理论
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Short-Term Financing of Economic Order Quantity (EOQ) Inventory Model With Probabilistic Quality
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作者 Mahmoud Arayssi Noura Yassine 《Journal of Modern Accounting and Auditing》 2014年第7期793-802,共10页
In this paper, the classical economic order quantity (EOQ) inventory model assumption that all items of a certain product received from a supplier are of perfect quality is relaxed. Another basic assumption that the... In this paper, the classical economic order quantity (EOQ) inventory model assumption that all items of a certain product received from a supplier are of perfect quality is relaxed. Another basic assumption that the payment for the items is made at the beginning of the inventory cycle when they are received is also eased. We consider an inventory situation where items received from the supplier are of two types of quality, perfect and imperfect, and a short deferral in payment is allowed. The split between perfect and imperfect quality items is assumed to follow a known probability distribution. Both qualities of items have continuous demands, and items of imperfect quality are sold at a discount. A mathematical model is developed using the net present value of all cash flows involved in the inventory cycle. A numerical method for obtaining the optimal order quantity is presented, and the impact of the short-term financing is analyzed. An example is presented to validate the equations and illustrate the results. 展开更多
关键词 economic order quantity (EOQ) imperfect quality items continuous demand allowed deferred payment net present value financing policies operations planning
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中考化学计算题的复习
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作者 董艳辉 《中学化学教学参考》 2014年第4X期31-31,共1页
一、问题的提出化学计算是学生要掌握的基本技能之一,它可以使学生从量的角度来理解物质及其变化规律。学生在学习中易解错题是教学过程中普遍存在的问题,原因除了学生对化学基本知识缺乏深刻理解外,主要是没有掌握解题的策略与技巧,不... 一、问题的提出化学计算是学生要掌握的基本技能之一,它可以使学生从量的角度来理解物质及其变化规律。学生在学习中易解错题是教学过程中普遍存在的问题,原因除了学生对化学基本知识缺乏深刻理解外,主要是没有掌握解题的策略与技巧,不能适应试题的迁移和变化。如何在化学计算题的复习中帮助学生弄清化学概念,掌握解题的策略与技巧,是化学计算题复习的关键。二、实施的办法和途径1.弄清概念。 展开更多
关键词 化学计算 化学概念 教学过程 初中化学 解题技巧 氧化铜粉 氧化锰 解题过程 思维能力 假设量
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Empirical likelihood hypothesis test on mean with inequality constraints 被引量:1
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作者 CHEN Li SHI Jian 《Science China Mathematics》 SCIE 2011年第9期1847-1857,共11页
Hypothesis test on the population mean with various inequality constraints is studied in this paper.The empirical likelihood method is applied to construct test statistics.Limiting distributions of the empirical likel... Hypothesis test on the population mean with various inequality constraints is studied in this paper.The empirical likelihood method is applied to construct test statistics.Limiting distributions of the empirical likelihood ratio test statistics are proven to be a weighted mixture of chi-square distributions.Numerical results are presented to show the validity of the proposed method. 展开更多
关键词 empirical likelihood hypothesis test inequality constraint chi-bar square least favorable point
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INFERENCE ON COEFFICIENT FUNCTION FOR VARYING-COEFFICIENT PARTIALLY LINEAR MODEL
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作者 Jingyan FENG Riquan ZHANG 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2012年第6期1143-1157,共15页
One important model in handling the multivariate data is the varying-coefficient partially linear regression model. In this paper, the generalized likelihood ratio test is developed to test whether its coefficient fun... One important model in handling the multivariate data is the varying-coefficient partially linear regression model. In this paper, the generalized likelihood ratio test is developed to test whether its coefficient functions are varying or not. It is showed that the normalized proposed test follows asymptotically x2-distribution and the Wilks phenomenon under the null hypothesis, and its asymptotic power achieves the optimal rate of the convergence for the nonparametric hypotheses testing. Some simulation studies illustrate that the test works well. 展开更多
关键词 x2-distribution generalized likelihood ratio optimal rate of convergence varying-coefficientpartially linear model Wilks phenomenon.
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Randomly Weighted LAD-Estimation for Partially Linear Errors-in-Variables Models
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作者 Xiaohan YANG Rong JIANG Weimin QIAN 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2015年第4期561-578,共18页
The authors consider the partially linear model relating a response Y to predictors (x, T) with a mean function x^Tβ0 + g(T) when the x's are measured with an additive error. The estimators of parameter β0 are... The authors consider the partially linear model relating a response Y to predictors (x, T) with a mean function x^Tβ0 + g(T) when the x's are measured with an additive error. The estimators of parameter β0 are derived by using the nearest neighbor-generalized randomly weighted least absolute deviation (LAD for short) method. The resulting estimator of the unknown vector 30 is shown to be consistent and asymptotically normal. In addition, the results facilitate the construction of confidence regions and the hypothesis testing for the unknown parameters. Extensive simulations are reported, showing that the proposed method works well in practical settings. The proposed methods are also applied to a data set from the study of an AIDS clinical trial group. 展开更多
关键词 Partially linear errors-in-variables LAD-estimation Randomly weighted method Linear hypothesis Randomly weighted LAD-test
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Study on Lag time Model of Fire Plume under a Sloped Ceiling 被引量:1
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作者 WANG Jinhui LI Guoqiang 《Journal of Thermal Science》 SCIE EI CAS CSCD 2014年第5期486-493,共8页
It is known that there is a lag time for smoke plume induced by fires transporting from a fire origin to the location of interest underneath an unconfined and flat ceiling.This lag behavior of smoke plume also exists ... It is known that there is a lag time for smoke plume induced by fires transporting from a fire origin to the location of interest underneath an unconfined and flat ceiling.This lag behavior of smoke plume also exists for a fire under a sloped ceiling,and is fundamental to estimate the activation time of a fire detector or other fire extinguishing system.This study focuses on the lag time of smoke plume under a sloped ceiling.Based on the weak-plume theory at early-fire phase and previous studies concerning the fire plume characteristics under a sloped ceiling,a calculation method on lag time of fire plume transporting is presented in theory.Meanwhile,two dimensionless equations predicting the lag time of fire plume for steady fire and unsteady fire are proposed respectively.Furthermore,the critical time calculation equation is also proposed to determine the applicability of quasi-steady assumption for a time-dependent fire. 展开更多
关键词 Fire Smoke plume Lag time Quasi-steady assumption Sloped ceiling
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