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基于同时定位与地图构建的AUV导航定位方法综述 被引量:7
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作者 聂永芳 潘爽 +1 位作者 孙东平 施建礼 《航天控制》 CSCD 北大核心 2018年第3期79-85,98,共8页
同时定位与地图构建(SLAM)方法是自主式水下机器人导航领域的研究热点。首先介绍了水下SLAM算法的发展现状,总结了水下SLAM的主要实现方法和目前存在的难点问题,最后探讨了水下SLAM的发展趋势。
关键词 同时定位与地图构建 自主式水下机器人 扩展卡尔曼滤波 FastSLAM数据关联
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织构刀-屑界面滑移区微通道特性数值研究
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作者 逄明华 申福猴 +1 位作者 聂永芳 马利杰 《润滑与密封》 CAS CSCD 北大核心 2019年第3期30-36,共7页
刀-屑界面滑移区的接触及微通道分布特性直接影响切削液的渗入和刀-屑界面摩擦,对金属切削过程有着重要的影响,针对滑移区接触及微通道分布特性测量难、切削液在刀-屑界面渗入不易量化等问题,建立微织构粗糙刀-屑界面滑移区的接触数值模... 刀-屑界面滑移区的接触及微通道分布特性直接影响切削液的渗入和刀-屑界面摩擦,对金属切削过程有着重要的影响,针对滑移区接触及微通道分布特性测量难、切削液在刀-屑界面渗入不易量化等问题,建立微织构粗糙刀-屑界面滑移区的接触数值模型,分析滑移区的接触、微通道分布特性以及微织构作用机制。研究表明:滑移区存在3种不同的宏观接触特性,分别为近黏结特性、微通道特性和近分离特性;在近黏结特性区内,刀-屑界面不存在微通道,微织构主要功能为减少刀-屑界面接触面积;在微通道特性区内,刀-屑界面存在大量微通道,微织构主要功能为连接微通道;在近分离特性区内,刀-屑界面微通道消失,微织构主要功能为存储切削液。刀-屑界面应力分布系数对各特性区长度有影响,应力分布系数减小,近黏结区和微通道区长度增大,而近分离区长度相应减小。 展开更多
关键词 微织构 刀-屑界面 滑移区 微通道
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Improved pruning algorithm for Gaussian mixture probability hypothesis density filter 被引量:7
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作者 nie yongfang ZHANG Tao 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第2期229-235,共7页
With the increment of the number of Gaussian components, the computation cost increases in the Gaussian mixture probability hypothesis density(GM-PHD) filter. Based on the theory of Chen et al, we propose an improved ... With the increment of the number of Gaussian components, the computation cost increases in the Gaussian mixture probability hypothesis density(GM-PHD) filter. Based on the theory of Chen et al, we propose an improved pruning algorithm for the GM-PHD filter, which utilizes not only the Gaussian components’ means and covariance, but their weights as a new criterion to improve the estimate accuracy of the conventional pruning algorithm for tracking very closely proximity targets. Moreover, it solves the end-less while-loop problem without the need of a second merging step. Simulation results show that this improved algorithm is easier to implement and more robust than the formal ones. 展开更多
关键词 Gaussian mixture probability hypothesis density(GM-PHD) filter pruning algorithm proximity targets clutter rate
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Scaling parameters selection principle for the scaled unscented Kalman filter 被引量:1
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作者 nie yongfang ZHANG Tao 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第3期601-610,共10页
The paper deals with the state estimation of the widely used scaled unscented Kalman filter(UKF). In particular, the stress is laid on the scaling parameters selection principle for the scaled UKF. Several problems ... The paper deals with the state estimation of the widely used scaled unscented Kalman filter(UKF). In particular, the stress is laid on the scaling parameters selection principle for the scaled UKF. Several problems caused by recommended constant scaling parameters are highlighted. On the basis of the analyses, an effective scaled UKF is proposed with self-adaptive scaling parameters,which is easy to understand and implement in engineering. Two typical strong nonlinear examples are given and their simulation results show the effectiveness of the proposed principle and algorithm. 展开更多
关键词 nonlinear filtering scaled unscented Kalman filter scaling parameter selection principle
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Detection Precision of Seedmeter for Large-granule Seeds
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作者 nie yongfang CHENG Jianfeng +2 位作者 ZHANG Sujun CAO Jun WANG Yushun 《Journal of Northeast Agricultural University(English Edition)》 CAS 2011年第1期63-66,共4页
A detecting method based on machine vision was put forward to test the performance of seedmeter with corn and soybean seeds as test samples,in which MATLAB software was applied to process image data and analyze the re... A detecting method based on machine vision was put forward to test the performance of seedmeter with corn and soybean seeds as test samples,in which MATLAB software was applied to process image data and analyze the results.The experimental results showed that the mean value of absolute error of the sowing speed for soybean was 0.004-0.68 seed ? s-1;the mean value of relative error was from 6.5% to 130%,and there were no significant differences of mean value,standard deviation and coefficient of variation of flowing seeds between manual statistics and MATLAB statistics.The machine vision method was proved to be time-saving,labor-saving and no-touching in the seedmeter precision detecting. 展开更多
关键词 seedmeter detection precision machine vision image processing
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RNF8/RNF168信号通路在DNA损伤修复中的作用 被引量:1
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作者 刘振华 聂永芳 +1 位作者 朱建 庄婷 《基因组学与应用生物学》 CAS CSCD 北大核心 2019年第2期618-623,共6页
细胞内DNA会受部分外界因素(如紫外辐射,电离辐射和化学毒素)和内部因素(如复制错误)的影响而发生损伤,包括DNA双链断裂、DNA错配和DNA交链等。DNA损伤发生后,损伤部位会被一些蛋白识别,进而招募一系列蛋白至损伤部位,形成一个修复系统... 细胞内DNA会受部分外界因素(如紫外辐射,电离辐射和化学毒素)和内部因素(如复制错误)的影响而发生损伤,包括DNA双链断裂、DNA错配和DNA交链等。DNA损伤发生后,损伤部位会被一些蛋白识别,进而招募一系列蛋白至损伤部位,形成一个修复系统。DNA双链断裂是最严重的一种DNA损伤,错误修复往往导致疾病的发生。DNA双链断裂(double strand break, DSB)后,细胞启动RNF8/RNF168信号通路进行修复。RNF8和RNF168是这条通路的枢纽蛋白;53BP和BRCA1是关键的效应蛋白,决定着DSB修复的方式;组蛋白泛素化、磷酸化和甲基化等翻译后修饰是这条通路顺利进行的基本条件;染色质重塑、泛素化酶/去泛素化酶平衡和蛋白稳定性是这条通路的主要调节方式。本综述对RNF8/RNF168信号通路进行了梳理总结,希望其能对相关研究者起到参考作用。 展开更多
关键词 DNA损伤应答 DNA双链断裂 RNF8 RNF168 53BP BRCA1 组蛋白 泛素化
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