期刊文献+
共找到675篇文章
< 1 2 34 >
每页显示 20 50 100
Multiple-target tracking with adaptive sampling intervals for phased-array radar 被引量:10
1
作者 Zhenkai Zhang Jianjiang Zhou +2 位作者 Fei Wang Weiqiang Liu Hongbing Yang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2011年第5期760-766,共7页
A novel adaptive sampling interval algorithm for multitarget tracking is presented. This algorithm which is based on interacting multiple models incorporates the grey relational grade (GRG) into the particle swarm o... A novel adaptive sampling interval algorithm for multitarget tracking is presented. This algorithm which is based on interacting multiple models incorporates the grey relational grade (GRG) into the particle swarm optimization (PSO). Firstly, the desired tracking accuracy is set for each target. Secondly, sampling intervals are selected as particles, and then the advantage of the GRG is taken as the measurement function for resource management. Meanwhile, the fitness value of the PSO is used to measure the difference between desired tracking accuracy and estimated tracking accuracy. Finally, it is suggested that the radar should track the target whose prediction value of the next sampling interval is the smallest. Simulations show that the proposed method improves both the tracking accuracy and tracking efficiency of the phased-array radar. 展开更多
关键词 target tracking adaptive sampling interval (ASI) particle swarm optimization (PSO) grey relational grade (GRG) phased-array radar.
在线阅读 下载PDF
Joint optimization of sampling interval and control for condition-based maintenance using availability maximization criterion 被引量:1
2
作者 LI Xin CAI Jing +3 位作者 ZUO Hongfu LIU Ruochen CHEN Xi GUO Jiachen 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第1期203-215,共13页
Most of the maintenance optimization models in condition-based maintenance(CBM) consider the cost-optimal criterion, but few papers have dealt with availability maximization for maintenance applications. A novel optim... Most of the maintenance optimization models in condition-based maintenance(CBM) consider the cost-optimal criterion, but few papers have dealt with availability maximization for maintenance applications. A novel optimal Bayesian control approach is presented for maintenance decision making. The system deterioration evolves as a three-state continuous time hidden semi-Markov process. Considering the optimal maintenance policy, the multivariate Bayesian control scheme based on the hidden semi-Markov model(HSMM) is developed, the objective is to maximize the long-run expected average availability per unit time. The proposed approach can optimize the sampling interval and control limit jointly. A case study using Markov chain Monte Carlo(MCMC)simulation is provided and a comparison with the Bayesian control scheme based on hidden Markov model(HMM), the age-based replacement policy, Hotelling’s T2, multivariate exponentially weihted moving average(MEWMA) and multivariate cumulative sum(MCUSUM) control charts is given, which illustrates the effectiveness of the proposed method. 展开更多
关键词 condition-based maintenance(CBM) availability maximization Markov chain Monte Carlo(MCMC) hidden semiMarkov model(HSMM) Bayesian control sampling interval
在线阅读 下载PDF
Impact of sampling interval on variance components of epoch-wise residual error in relative GPS positioning: A case study of a 40-km-long baseline
3
作者 Darko Andic 《Geodesy and Geodynamics》 CSCD 2021年第5期368-380,共13页
The study presents sampling interval impacts on variance components of the epoch-wise residual errors in relative GPS positioning. In the variance components estimation process, the 2-way nested ANOVA method was used.... The study presents sampling interval impacts on variance components of the epoch-wise residual errors in relative GPS positioning. In the variance components estimation process, the 2-way nested ANOVA method was used. For that purpose, GPS observation data during four months at two permanent GPS stations, establishing a 40-km-long baseline as a part of the Montenegrin permanent network(Monte Pos), were used. The study results showed that there is no statistically significant impact of sampling interval changes on epoch-wise variance components related to the residual tropospheric and ionospheric delays(effect a) when it comes to such a baseline. However, it is not the case with epoch-wise variance components related to the interstation-distance-independent residual ‘far-field’ multipath effect(effect b). It turned out that the absolute values of relative differences of standard deviations of the effect a on the relative GPS coordinates(e, n and u) had maximum values 11.1%, 10.2% and 8.9%,respectively. Keeping the same order of presentation for the effect b, the values of 5.9%, 9.9% and 12.5%were obtained. In addition, absolute values of relative differences of standard deviations of horizontal and vertical position had maximum values of 3.8% and 7.7%, respectively. 展开更多
关键词 Relative GPS positioning Residual effects Variance components Positional accuracy sampling interval
原文传递
Scatter factor confidence interval estimate of least square maximum entropy quantile function for small samples 被引量:3
4
作者 Wu Fuxian Wen Weidong 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2016年第5期1285-1293,共9页
Classic maximum entropy quantile function method (CMEQFM) based on the probability weighted moments (PWMs) can accurately estimate the quantile function of random variable on small samples, but inaccurately on the... Classic maximum entropy quantile function method (CMEQFM) based on the probability weighted moments (PWMs) can accurately estimate the quantile function of random variable on small samples, but inaccurately on the very small samples. To overcome this weakness, least square maximum entropy quantile function method (LSMEQFM) and that with constraint condition (LSMEQFMCC) are proposed. To improve the confidence level of quantile function estimation, scatter factor method is combined with maximum entropy method to estimate the confidence interval of quantile function. From the comparisons of these methods about two common probability distributions and one engineering application, it is showed that CMEQFM can estimate the quantile function accurately on the small samples but inaccurately on the very small samples (10 samples); LSMEQFM and LSMEQFMCC can be successfully applied to the very small samples; with consideration of the constraint condition on quantile function, LSMEQFMCC is more stable and computationally accurate than LSMEQFM; scatter factor confidence interval estimation method based on LSMEQFM or LSMEQFMCC has good estimation accuracy on the confidence interval of quantile function, and that based on LSMEQFMCC is the most stable and accurate method on the very small samples (10 samples). 展开更多
关键词 Confidence intervals Maximum entropy Quantile function RELIABILITY Scatter factor Small samples
原文传递
Influence of sampling on three-dimensional surface shape measurement
5
作者 QIAO Nao-sheng Shang Xue 《中国光学(中英文)》 EI CAS CSCD 北大核心 2024年第6期1512-1520,共9页
In order to accurately measure an object’s three-dimensional surface shape,the influence of sampling on it was studied.First,on the basis of deriving spectra expressions through the Fourier transform,the generation o... In order to accurately measure an object’s three-dimensional surface shape,the influence of sampling on it was studied.First,on the basis of deriving spectra expressions through the Fourier transform,the generation of CCD pixels was analyzed,and its expression was given.Then,based on the discrete expression of deformation fringes obtained after sampling,its Fourier spectrum expression was derived,resulting in an infinitely repeated"spectra island"in the frequency domain.Finally,on the basis of using a low-pass filter to remove high-order harmonic components and retaining only one fundamental frequency component,the inverse Fourier transform was used to reconstruct the signal strength.A method of reducing the sampling interval,i.e.,reducing the number of sampling points per fringe,was proposed to increase the ratio between the sampling frequency and the fundamental frequency of the grating.This was done to reconstruct the object’s surface shape more accurately under the condition of m>4.The basic principle was verified through simulation and experiment.In the simulation,the sampling intervals were 8 pixels,4 pixels,2 pixels,and 1 pixel,the maximum absolute error values obtained in the last three situations were 88.80%,38.38%,and 31.50%in the first situation,respectively,and the corresponding average absolute error values are 71.84%,43.27%,and 32.26%.It is demonstrated that the smaller the sampling interval,the better the recovery effect.Taking the same four sampling intervals in the experiment as in the simulation can also lead to the same conclusions.The simulated and experimental results show that reducing the sampling interval can improve the accuracy of object surface shape measurement and achieve better reconstruction results. 展开更多
关键词 three-dimensional surface shape measurement sampling interval spectra overlapping measurement accuracy
在线阅读 下载PDF
Stability and Stabilization of Sampled-Data Based LFC for Power Systems:A Data-Driven Method
6
作者 Yu-Long Fan Chuan-Ke Zhang Yong He 《IEEE/CAA Journal of Automatica Sinica》 2025年第1期291-293,共3页
Dear Editor,This letter is concerned with stability analysis and stabilization design for sampled-data based load frequency control(LFC) systems via a data-driven method. By describing the dynamic behavior of LFC syst... Dear Editor,This letter is concerned with stability analysis and stabilization design for sampled-data based load frequency control(LFC) systems via a data-driven method. By describing the dynamic behavior of LFC systems based on a data-based representation, a stability criterion is derived to obtain the admissible maximum sampling interval(MSI) for a given controller and a design condition of the PI-type controller is further developed to meet the required MSI. Finally, the effectiveness of the proposed methods is verified by a case study. 展开更多
关键词 sampling interval msi lfc systems stability analysis stability criterion design condition load frequency control lfc stabilization design
在线阅读 下载PDF
Statistical Analysis for Constant-stress Partially Accelerated Life Test with Interval Censored Data 被引量:2
7
作者 LONG Bing ZHANG Zhong-zhan 《Chinese Quarterly Journal of Mathematics》 2019年第1期1-13,共13页
In this paper, a statistical analysis method is proposed to research life characteristics of products based on the partially accelerated life test. We discuss the statistical analysis for constant-stress partially acc... In this paper, a statistical analysis method is proposed to research life characteristics of products based on the partially accelerated life test. We discuss the statistical analysis for constant-stress partially accelerated life tests with Lomax distribution based on interval censored samples. The EM algorithm is used to obtain the maximum likelihood estimations(MLEs) and interval estimations for the shape parameter and acceleration factor.The average relative errors(AREs), mean square errors(MSEs), the confidence intervals for the parameters, and the influence of the sample size are discussed. The results show that the AREs and MSEs of the MLEs decrease with the increase of sample size. Finally, a simulation sample is used to estimate the reliability under different stress levels. 展开更多
关键词 interval censored samplES PARTIALLY ACCELERATED life test ACCELERATED factor EM algorithm FISHER information matrix
在线阅读 下载PDF
Characteristic wavelength selection of volatile organic compounds infrared spectra based on improved interval partial least squares 被引量:2
8
作者 Wei Ju Changhua Lu +4 位作者 Yujun Zhang Weiwei Jiang Jizhou Wang Yi Bing Lu Feng Hong 《Journal of Innovative Optical Health Sciences》 SCIE EI CAS 2019年第2期35-53,共19页
As important components of air pollutant,volatile organic compounds(VOCs)can cause great harm to environment and human body.The concentration change of VOCs should be focused on in real-time environment monitoring sys... As important components of air pollutant,volatile organic compounds(VOCs)can cause great harm to environment and human body.The concentration change of VOCs should be focused on in real-time environment monitoring system.In order to solve the problem of wavelength redundancy in full spectrum partial least squares(PLS)modeling for VOCs concentration analysis,a new method based on improved interval PLS(iPLS)integrated with Monte-Carlo sampling,called iPLS-MC method,was proposed to select optimal characteristic wavelengths of VOCs spectra.This method uses iPLS modeling to preselect the characteristic wavebands of the spectra and generates random wavelength combinations from the selected wavebands by Monte-Carlo sampling.The wavelength combination with the best prediction result in regression model is selected as the characteristic wavelengths of the spectrum.Different wavelength selection methods were built,respectively,on Fourier transform infrared(FTIR)spectra of ethylene and ethanol gas at different concentrations obtained in the laboratory.When the interval number of iPLS model is set to 30 and the Monte-Carlo sampling runs 1000 times,the characteristic wavelengths selected by iPLS-MC method can reduce from 8916 to 10,which occupies only 0.22%of the full spectrum wavelengths.While the RMSECV and correlation coefficient(Rc)for ethylene are 0.2977 and 0.9999 ppm,and those for ethanol gas are 0.2977 ppm and 0.9999.The experimental results show that the iPLS-MC method can select the optimal characteristic wavelengths of VOCs FTIR spectra stably and effectively,and the prediction performance of the regression model can be significantly improved and simplified by using characteristic wavelengths. 展开更多
关键词 Ambient air monitoring Fourier transform infrared spectra analysis variable selection interval partial least square Monte-Carlo sampling
原文传递
Sealing reliability modeling of aviation seal based on interval uncertainty method and multidimensional response surface 被引量:5
9
作者 Baopeng LIAO Bo SUN +5 位作者 Yu LI Meichen YAN Yi REN Qiang FENG Dezhen YANG Kun ZHOU 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2019年第9期2188-2198,共11页
Many variables affect the sealing performance, and their distribution characteristics are difficult to obtain with probabilistic methods owing to the high cost involved. Numerous problems in engineering are similar du... Many variables affect the sealing performance, and their distribution characteristics are difficult to obtain with probabilistic methods owing to the high cost involved. Numerous problems in engineering are similar due to the appearance of small-sample parameters. In this study, the sealing reliability of an aviation seal was defined as the research object, and an interval uncertainty method and multidimensional response surface were proposed to calculate the sealing reliability.Based on this, we first analyzed the failure mechanism of the aviation seal and established a leakage rate model. Then, based on the non-probabilistic interval model, an interval uncertainty method was proposed to construct the analytical model. With reference to the limit state equation from the structural reliability theory, the multidimensional response surface was used for fast calculation.Then, we chose the single-cylinder gas steering gear used in aircraft as the case study, its sealing reliability in working and non-working statuses were calculated, and the results were verified with the actual maintenance records. By analyzing the sensitivity of some variables, we can improve the sealing reliability of the aviation seal by improving the surface roughness only if the cost allows.Finally, we consider that the method proposed in this study realizes the application of smallsample uncertainty analysis in reliability analysis, and could provide a feasible way to solve the similar problems in engineering with multidimensional and small-sample parameters. 展开更多
关键词 AVIATION SEAL interval uncertainty METHOD MULTIDIMENSIONAL response surface SEALING RELIABILITY Small-sample parameters
原文传递
Novel Stability Criteria for Sampled-Data Systems With Variable Sampling Periods 被引量:2
10
作者 Hanyong Shao Jianrong Zhao Dan Zhang 《IEEE/CAA Journal of Automatica Sinica》 EI CSCD 2020年第1期257-262,共6页
This paper is concerned with a novel Lyapunovlike functional approach to the stability of sampled-data systems with variable sampling periods. The Lyapunov-like functional has four striking characters compared to usua... This paper is concerned with a novel Lyapunovlike functional approach to the stability of sampled-data systems with variable sampling periods. The Lyapunov-like functional has four striking characters compared to usual ones. First, it is time-dependent. Second, it may be discontinuous. Third, not every term of it is required to be positive definite. Fourth, the Lyapunov functional includes not only the state and the sampled state but also the integral of the state. By using a recently reported inequality to estimate the derivative of this Lyapunov functional, a sampled-interval-dependent stability criterion with reduced conservatism is obtained. The stability criterion is further extended to sampled-data systems with polytopic uncertainties. Finally, three examples are given to illustrate the reduced conservatism of the stability criteria. 展开更多
关键词 Lyapunov functional sampled-data systems sampling-interval-dependent stability
在线阅读 下载PDF
An On-Line Modeling Based Kalman Filtering Process for Time-Interval-Variable Sequences with Application to Astronomic Surveying
11
作者 韩建国 孙才红 李彦琴 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2003年第2期52-56,共5页
The problem of variable sampling time interval which appears in application of Kalman Filtering is analyzed and the corresponding filtering process with or without present transition matrix is suggested, then an appli... The problem of variable sampling time interval which appears in application of Kalman Filtering is analyzed and the corresponding filtering process with or without present transition matrix is suggested, then an application experiment for astronomical surveying is introduced. In this process, the known stochastically variable sampling time intervals play the roles as deterministic input sequences of the state-space description, and the corresponding matrix and (if needed) state transition matrix can be established by performing real-time and structure-linear system identification. 展开更多
关键词 Kalman filtering Variable sampling time interval Real-time and structure-linear system identification.
在线阅读 下载PDF
Distributed model predictive control based on adaptive sampling mechanism
12
作者 Zhen Wang Aimin An Qianrong Li 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2021年第11期193-204,共12页
In this work,an adaptive sampling control strategy for distributed predictive control is proposed.According to the proposed method,the sampling rate of each subsystem of the accused object is determined based on the p... In this work,an adaptive sampling control strategy for distributed predictive control is proposed.According to the proposed method,the sampling rate of each subsystem of the accused object is determined based on the periodic detection of its dynamic behavior and calculations made using a correlation function.Then,the optimal sampling interval within the period is obtained and sent to the corresponding sub-prediction controller,and the sampling interval of the controller is changed accordingly before the next sampling period begins.In the next control period,the adaptive sampling mechanism recalculates the sampling rate of each subsystem’s measurable output variable according to both the abovementioned method and the change in the dynamic behavior of the entire system,and this process is repeated.Such an adaptive sampling interval selection based on an autocorrelation function that measures dynamic behavior can dynamically optimize the selection of sampling rate according to the real-time change in the dynamic behavior of the controlled object.It can also accurately capture dynamic changes,meaning that each sub-prediction controller can more accurately calculate the optimal control quantity at the next moment,significantly improving the performance of distributed model predictive control(DMPC).A comparison demonstrates that the proposed adaptive sampling DMPC algorithm has better tracking performance than the traditional DMPC algorithm. 展开更多
关键词 Chemical process Distributed model predictive control Adaptive sampling mechanism Optimal sampling interval System dynamic behavior
在线阅读 下载PDF
The Performance of Double Bootstrap Method for Large Sampling Sequence
13
作者 Muhamad Safiih Lola Nurul Hila Zainuddin 《Open Journal of Statistics》 2016年第5期805-813,共10页
Studies on the iteration procedure in double bootstrap method have given a great impact on confidence interval performance. However, the procedure was claimed to be complicated and demand intensive computer processor.... Studies on the iteration procedure in double bootstrap method have given a great impact on confidence interval performance. However, the procedure was claimed to be complicated and demand intensive computer processor. Considering this problem, an alternative procedure was proposed in this research. Despite of using small sampling sequence, this research was aimed to increase the accuracy estimation using a second replication number which resulted in a large sampling sequence of double bootstrap. In this paper, the alternative double bootstrap method was hybrid onto an example model and its performance was based on Studentised interval. The performance was examined in simulation study and real sample data of sukuk Ijarah. The result showed that hybrid double bootstrap model gave more accurate estimation in terms of its shorter length when dealing with various parameter values and has shown to improve the single bootstrap estimation. 展开更多
关键词 Double Bootstrap Confidence interval sampling Sequence EWMA Sukuk Ijarah
在线阅读 下载PDF
不同采样间隔下GNSS-IR海面高度反演方法分析 被引量:1
14
作者 王硕 贺凯飞 +2 位作者 颜舒琳 侯金华 邹宗瑞 《导航定位学报》 北大核心 2025年第3期52-61,共10页
全球导航卫星系统反射干涉测量(GNSS-IR)可使用信噪比数据来反演海平面高度。不同测站全球卫星导航系统(GNSS)观测数据常用采样间隔不同,不同反演方法的适用性不同,为研究不同采样间隔在不同方法下的反演效果,利用美国SC02站、澳大利亚S... 全球导航卫星系统反射干涉测量(GNSS-IR)可使用信噪比数据来反演海平面高度。不同测站全球卫星导航系统(GNSS)观测数据常用采样间隔不同,不同反演方法的适用性不同,为研究不同采样间隔在不同方法下的反演效果,利用美国SC02站、澳大利亚SPBY站和非洲东海岸MAYG站GNSS观测数据,采用经典周期图(Lomb-Scargle)、变分模态分解及小波分解3种方法分别处理1、5、15、30 s常用采样间隔的GNSS观测数据。实验结果表明,采样间隔和反演精度整体上呈负相关,小波分解法在1、5、15 s采样间隔下反演结果最优,且受采样间隔影响最大;Lomb-Scargle法在30 s采样间隔下最优,其受影响最小;另外S5信号反演结果比S1信号受采样间隔影响更小。 展开更多
关键词 全球卫星导航系统反射干涉测量(GNSS-IR) 信噪比 海平面高度 采样间隔 周期图(Lomb-Scargle) 变分模态分解 小波分解
在线阅读 下载PDF
基于贝叶斯优化ESN的PEMFC性能退化预测
15
作者 陈进 靳佳澍 +2 位作者 陈跃鹏 谢长君 刘柏均 《中国电机工程学报》 北大核心 2025年第16期6437-6448,I0024,共13页
质子交换膜燃料电池(proton exchange membrane fuel cell,PEMFC)的耐久性不足是困扰其自身大规模商业化的问题之一。该文提出一种贝叶斯优化(bayesian optimization,BO)算法优化回声状态网络(echo state network,ESN)模型进行PEMFC性... 质子交换膜燃料电池(proton exchange membrane fuel cell,PEMFC)的耐久性不足是困扰其自身大规模商业化的问题之一。该文提出一种贝叶斯优化(bayesian optimization,BO)算法优化回声状态网络(echo state network,ESN)模型进行PEMFC性能退化预测。通过BO获取ESN模型的最优超参数组,利用ESN模型预测PEMFC电压。此外,电压下降是PEMFC性能退化的重要表征之一,电压下降迅速的地方包含更多的性能退化特征信息,需要进行更频繁的采样;电压下降程度较小的地方包含较少的性能退化特征信息,需要进行较低频率采样。因此,该文提出一种自适应模糊规则采样(adaptive fuzzy sampling,AFS)对数据集进行采样提升PEMFC预测精度。结果表明,在静态工况中,BO-ESN的均方根误差(root mean square error,RMSE)和平均百分比误差(mean absolutepercentage error,MAPE)分别比ESN模型降低52.4%和63.6%。经AFS采样后BO-ESN模型的RMSE和MAPE分别比固定时间间隔采样降低49.8%和54.5%。在动态工况中,BO-ESN模型相比于ESN模型的RMSE和MAPE分别降低13.4%和7.96%。该方法具有较好的PEMFC性能退化预测性能。 展开更多
关键词 贝叶斯优化 回声状态网络 自适应模糊规则采样 置信区间 性能退化
原文传递
给定置信水平及区间长度的总体标准差估计所需样本量准确计算方法
16
作者 王存良 朱喜明 《电光系统》 2025年第2期29-33,共5页
文章基于经典理论的总体标准差一定置信水平的置信区间及其长度,首次提出一种解三元方程组获得所需样本量的准确算法,使得样本量满足置信水平置信区间及其长度要求。文中建立的3个方程不存在近似,利用MathCAD数学工具软件解方程组得到... 文章基于经典理论的总体标准差一定置信水平的置信区间及其长度,首次提出一种解三元方程组获得所需样本量的准确算法,使得样本量满足置信水平置信区间及其长度要求。文中建立的3个方程不存在近似,利用MathCAD数学工具软件解方程组得到样本量及X^(2)_(0.5a)(n-1),X^(2)_(1-0.5a)(n-1)的值,计算置信区间,满足在一定置信水平的置信区间及其长度要求,验证了解算样本量的正确性,并与文献[1]的近似计算及结果进行了比对,近似计算与准确计算的样本量都用于计算经典理论的总体标准差一定置信水平的置信区间,显示了文中方法的准确性。 展开更多
关键词 总体标准差 置信水平 置信区间 样本容量 选代初值
在线阅读 下载PDF
粤东三维地震探测OBS时间记录问题分析与处理
17
作者 温庚庚 叶秀薇 +1 位作者 吕作勇 张严心 《地球物理学报》 北大核心 2025年第6期2292-2306,共15页
海底地震仪(OBS)时间记录校正是数据处理过程中至关重要的环节,是获取深部地壳精细速度结构的关键.本文基于2021年粤东海陆联合三维地震探测中的部分国产OBS数据,通过相邻文件时间间隔计算和测线交叉点处震相走时对比的方法发现了一类... 海底地震仪(OBS)时间记录校正是数据处理过程中至关重要的环节,是获取深部地壳精细速度结构的关键.本文基于2021年粤东海陆联合三维地震探测中的部分国产OBS数据,通过相邻文件时间间隔计算和测线交叉点处震相走时对比的方法发现了一类外部时间信息错误且存在采样间隔误差的OBS时间异常,并根据震相走时差精确计算了实际采样间隔,进而通过修改数据文件道头时间和数据重采样校正了该类时间误差,时间校正精度优于100ms.此外,本文还利用邻近测线直达波走时信息对岛屿附近无测线穿过或仅有单条测线穿过的OBS进行时间和位置校正,取得了良好的效果.通过对OBS时间记录问题的分析与校正,为下一步构建粤东海陆交互带三维地壳速度模型奠定重要基础,并为今后三维OBS地震探测数据处理提供参考和借鉴. 展开更多
关键词 海底地震仪(OBS) OBS时间异常 采样间隔误差 三维地震探测
在线阅读 下载PDF
梅花鹿野化行为研究中最佳行为采样的时间间隔
18
作者 邢燕 杨飞飞 +5 位作者 张迎祥 孙一群 郑颖 王春莹 王亮 姜广顺 《野生动物学报》 北大核心 2025年第1期186-193,共8页
梅花鹿(Cervus nippon)是温带森林中的重要有蹄类动物,亦是东北虎(Panthera tigris altaica)捕食的主要猎物之一。黑龙江太平沟国家级自然保护区作为东北虎跨境廊道,其野生梅花鹿种群在20世纪80年代已经野外灭绝,在保护区内,拟通过对圈... 梅花鹿(Cervus nippon)是温带森林中的重要有蹄类动物,亦是东北虎(Panthera tigris altaica)捕食的主要猎物之一。黑龙江太平沟国家级自然保护区作为东北虎跨境廊道,其野生梅花鹿种群在20世纪80年代已经野外灭绝,在保护区内,拟通过对圈养梅花鹿的行为野化,促进梅花鹿野外种群的快速恢复。然而,在行为研究过程中,瞬时扫描取样法虽然被广泛运用,但瞬时扫描具体采样间隔的科学性研究较少。因此,本研究在5、10、15、20、30、60 min不同采样间隔内得到梅花鹿的不同行为持续时间,使用线性回归的方法将不同行为持续时间进行两两比较,依据R^(2)≥0.9、截距与0无显著差异(P>0.05)、斜率与1无显著差异(P>0.05)3个标准衡量采样间隔是否可以准确估计行为的持续时间,进而确定最佳采样间隔。结果表明:运动行为最佳采样间隔为5 min,休息、摄食、社会和其他4类行为的最佳采样间隔为10 min,反刍、警戒和站立行为最佳采样间隔为15 min。本研究成果有助于确保行为数据收集的科学性,提升数据收集的效率。 展开更多
关键词 梅花鹿行为 瞬时扫描取样法 最佳采样间隔 野化训练
在线阅读 下载PDF
基于局部性原理的最大误差并行检测方法
19
作者 冀立光 杨鸿儒 +3 位作者 周玉畅 崔梦琦 何昊天 许瑾晨 《计算机科学》 北大核心 2025年第9期152-159,共8页
浮点数采用有限的位数来表示无限的实数进行计算,因此浮点数计算天然具有不准确性,这种不准确性可以用最大误差来度量。传统浮点数最大误差检测算法采用串行计算思维并结合经典搜索算法,当采样点数量较少时,容易将局部极大值作为全局最... 浮点数采用有限的位数来表示无限的实数进行计算,因此浮点数计算天然具有不准确性,这种不准确性可以用最大误差来度量。传统浮点数最大误差检测算法采用串行计算思维并结合经典搜索算法,当采样点数量较少时,容易将局部极大值作为全局最大值处理,从而遗漏最大误差值。如果大规模提升采样点数量,那么检测程序用时大幅增加,检测性能降低。通过应用并行计算模式指数级增加采样点数量,同步结合局部性原理在误差热点附近采用浮点动态采样策略,大幅提高检测结果的准确性。这种方法可以最大限度地发挥并行计算的算力,不仅可以提升浮点数最大误差的检测精度,还可以压缩检测程序的执行时间并提升性能,加速比可以达到1136.3,检测出的最大误差值优于当前主流检测工具,这为衡量浮点数计算指标提供了新的检测方法。 展开更多
关键词 浮点运算 并行优化 区间采样 误差检测 申威异构架构
在线阅读 下载PDF
考虑取样间隔的Barton标准JRC表征公式推导研究
20
作者 王刚 陈明瑞 +5 位作者 刘廷方 王长盛 吴学震 管辉 陈慧源 管尚尚 《河南理工大学学报(自然科学版)》 北大核心 2025年第5期152-160,共9页
目的为实现结构面粗糙度(JRC)的精确表征,本文选用粗糙度统计参数中的一阶导数均方根Z_(2)表征二维节理轮廓线粗糙度JRC2D。方法首先,使用Photoshop对10条Barton标准轮廓线分别开展修补断点、去除杂点、增强像素等图像优化工作,并将轮... 目的为实现结构面粗糙度(JRC)的精确表征,本文选用粗糙度统计参数中的一阶导数均方根Z_(2)表征二维节理轮廓线粗糙度JRC2D。方法首先,使用Photoshop对10条Barton标准轮廓线分别开展修补断点、去除杂点、增强像素等图像优化工作,并将轮廓线图像导入Matlab中,提取各轮廓线在不同取样间隔SI下的坐标数据,计算各条Barton标准JRC轮廓线在不同SI下的Z_(2)值;然后分析SI对Z_(2)的影响,基于Z_(2)随SI的增大而减小的规律,对各组数据的Z_(2)值、SI值进行指数函数拟合推导,调整拟合式参数后与JRC值进行回归拟合。结果获取了适用于SI∈[0.1 mm,2.0 mm]的JRC2D表征新公式,并引入参数JRCP对新公式的精确性进行验证,通过对比本文JRC-Z_(2)与前人JRC表征公式的计算结果,分析各条轮廓线的JRCP值变化规律。结论本文提出的考虑取样间隔的JRC-Z_(2)表征公式在其适用范围SI∈[0.1 mm,2.0 mm]内精确性更高,新公式更真实地表征了Barton标准JRC轮廓线的粗糙特性,研究成果可为准确评估结构面粗糙度提供理论参考。 展开更多
关键词 Barton标准轮廓线 结构面粗糙度 取样间隔 一阶导数均方根 指数拟合
在线阅读 下载PDF
上一页 1 2 34 下一页 到第
使用帮助 返回顶部