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单向S-粗集近似精度函数和依赖特性
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作者 夏佳荣 《杭州师范大学学报(自然科学版)》 CAS 2009年第6期401-406,共6页
利用单向S-粗集的动态特性和Pawlak粗集近似精度,提出了单向S-粗集的近似精度和它生成的近似精度函数,讨论并且得到了近似精度函数的数值特性与元素迁移的关系,近似精度和近似精度函数数值特性与属性的依赖之间的关系.
关键词 单向S-粗集 近似精度 近似精度函数
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采用逆函数平行弦截法求取高精度函数值
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作者 高孝敏 孙艳 赵亮 《科技信息》 2011年第26期320-320,322,共2页
迭代法是一种多次利用变量的旧值递推新值最终得到真值的计算过程。本文以弦截法为基础,采用逆函数的平行弦截法,针对可逆函数计算其高精度数值。此方法有精度高、收敛速度快、简单便捷、通用性强的特点。
关键词 函数 平行弦截法 迭代法 精度函数 有效数字
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有限精度函数理论与Einstein-Maxwell方程的光子解
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作者 陈光 《物理学报》 SCIE EI CAS CSCD 北大核心 2009年第5期2873-2877,共5页
提出了有限精度函数理论,并基于该理论求出了有限精度的Einstein-Maxwell方程的光子解,揭示了经典光子的电磁、引力与时空几何的重要性质.
关键词 有限精度函数理论 Einstein-Maxwell方程 光子解
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地震观测传递函数的精度问题 被引量:8
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作者 杨晓源 王翠芳 +1 位作者 戴仕贵 邵玉平 《地震地磁观测与研究》 2010年第6期32-39,共8页
数字地震观测的传递函数由反馈地震计和地震数据采集器的传递函数合成。地震数据采集器的传递函数主要用数字算法生成,其精度可以做得很高。反馈地震计是机电一体化的模拟传感部件,其传递函数的精度和稳定性均欠佳。尤其是由反馈地震计... 数字地震观测的传递函数由反馈地震计和地震数据采集器的传递函数合成。地震数据采集器的传递函数主要用数字算法生成,其精度可以做得很高。反馈地震计是机电一体化的模拟传感部件,其传递函数的精度和稳定性均欠佳。尤其是由反馈地震计生成的主导二阶极点,对应传统地震观测的周期和阻尼两个重要参数,其精度和稳定性往往较低,不利于地震学研究深入发展的需要。以四川地震观测的标定数据为例,说明数字地震观测传递函数的精度和稳定性急待改进。 展开更多
关键词 数字地震观测 传递函数精度和稳定性 主导二阶极点 工作周期和阻尼
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变精度变异函数S-粗集与F-结构
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作者 吴全荣 邱锦明 《武夷学院学报》 2008年第5期10-14,共5页
动态系统规律知识是规律对象(规律外延)与规律属性(规律内涵)的统一体,利用变异单向函数S-粗集与变精度粗集提出变精度变异单向函数S-粗集的概念和它的F-结构,给出变精度变异单向函数S-粗集的有关性质定理和推论,对此进行了讨论。应用... 动态系统规律知识是规律对象(规律外延)与规律属性(规律内涵)的统一体,利用变异单向函数S-粗集与变精度粗集提出变精度变异单向函数S-粗集的概念和它的F-结构,给出变精度变异单向函数S-粗集的有关性质定理和推论,对此进行了讨论。应用变精度变异函数单向S-粗集对动态系统的内涵规律的精度进行数据挖掘。容易挖掘-发现出动态系统中规律的相关性和规律的近似决策规则。变精度变异单向函数S-粗集为研究动态系统规律提供了一种新的途径。 展开更多
关键词 函数S-粗集 精度粗集 精度变异单向函数S-粗集 数据挖掘
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高精度Sigma-Delta调制器的建模设计 被引量:4
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作者 尹勇生 邓春菲 陈红梅 《微电子学与计算机》 CSCD 北大核心 2016年第5期28-32,共5页
基于MATLAB Simulink设计实现了一款单环三阶一位量化CIFF(Cascade-of-integrators,feedforward form)结构的高精度Sigma-Delta调制器.通过对噪声传输函数和系统反馈系数进行优化,提高了调制器的稳定性;分析了开关电容电路的主要误差影... 基于MATLAB Simulink设计实现了一款单环三阶一位量化CIFF(Cascade-of-integrators,feedforward form)结构的高精度Sigma-Delta调制器.通过对噪声传输函数和系统反馈系数进行优化,提高了调制器的稳定性;分析了开关电容电路的主要误差影响,为电路实现提供可靠的设计指导.仿真结果显示,在输入信号带宽为75Hz,过采样率为512时,理想调制器输出SNR高达148.3dB,ENOB为24.34bit;考虑非理想因素时,ENOB为22.02bit;电路级实现的调制器ENOB达20.94bit,表明该设计可实现低信号带宽下高精度转换. 展开更多
关键词 SIGMA-DELTA调制器 精度CIFF噪声传输函数 非理想因素
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六自由度电磁跟踪定位系统的设计研究 被引量:3
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作者 杨杰 邹锦 +2 位作者 李跃波 刘峰 潘征 《自动化与仪表》 2007年第5期34-37,共4页
针对用于模拟训练器材中的六自由度电磁跟踪定位系统,提出了一些新的硬件电路设计方案,对该方案进行了实验验证,并与理论分析结果进行了比较,验证了这些硬件电路的可行性。本设计方案有效测量距离可达到1.5m,角度测量误差小于1.60,对各... 针对用于模拟训练器材中的六自由度电磁跟踪定位系统,提出了一些新的硬件电路设计方案,对该方案进行了实验验证,并与理论分析结果进行了比较,验证了这些硬件电路的可行性。本设计方案有效测量距离可达到1.5m,角度测量误差小于1.60,对各种电磁定位系统的开发研究具有很大的参考价值。 展开更多
关键词 精度函数发生器 精密仪表放大器 数字可控放大器 三维环形天线
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基于CPLD控制的时序正弦信号发生器 被引量:4
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作者 殷勤 陈彬 汪莹 《电子测量技术》 2007年第11期123-125,共3页
本文根据六自由度电磁敏感定位系统的原理,采用高精度函数发生器MAX038,结合CPLD数字控制技术,设计了一种基于CPLD数字控制的时序正弦信号发生器。其发射正弦信号频率上限为20MHz,波形失真THD值为0.75%,为系统提供了精度较高、频率可调... 本文根据六自由度电磁敏感定位系统的原理,采用高精度函数发生器MAX038,结合CPLD数字控制技术,设计了一种基于CPLD数字控制的时序正弦信号发生器。其发射正弦信号频率上限为20MHz,波形失真THD值为0.75%,为系统提供了精度较高、频率可调的正弦信号。CPLD数字时序控制精度为纳秒级,解决了模拟电路时序控制信号受温度影响发生漂移的问题,实现了系统持续稳定工作,提高了系统的计算精度,使系统定位计算距离误差小于1cm,角度误差小于1°。 展开更多
关键词 电磁敏感定位系统 精度函数发生器 CPLD 数字控制
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毕达哥拉斯模糊数新的排序方法和运算法则 被引量:2
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作者 曾庄 黄天民 +1 位作者 赵庆庆 徐颖 《四川师范大学学报(自然科学版)》 CAS 北大核心 2020年第4期435-441,共7页
首先在全面考虑到隶属度、非隶属度、犹豫度三方面信息基础上,定义新的毕达哥拉斯模糊数(PFN)的记分函数和精度函数,得到一种新的排序方法.并且与旧的排序方法进行对比,说明新的记分函数和精度函数的合理性与有效性.然后在毕达哥拉斯模... 首先在全面考虑到隶属度、非隶属度、犹豫度三方面信息基础上,定义新的毕达哥拉斯模糊数(PFN)的记分函数和精度函数,得到一种新的排序方法.并且与旧的排序方法进行对比,说明新的记分函数和精度函数的合理性与有效性.然后在毕达哥拉斯模糊Einstein运算和毕达哥拉斯交叉影响集成运算的基础上,定义新的毕达哥拉斯模糊运算法则,给出相应的证明,并得到一些性质,丰富了毕达哥拉斯模集理论. 展开更多
关键词 直觉模糊集 毕达哥拉斯模糊数 记分函数 精度函数 毕达哥拉斯模糊数排序方法 毕达哥拉斯模糊数运算法则
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测量系统不确定度分析及其动态性研究 被引量:6
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作者 陈晓怀 谢少锋 +1 位作者 张勇斌 费业泰 《仪器仪表学报》 EI CAS CSCD 北大核心 2002年第z2期461-462,共2页
本文将不确定度原理引入测量系统分析,并对测量系统不确定度的动态性进行探讨研究,提出了基于灰色模型、时序分析和神经网络理论的精度损失函数的建模方法。
关键词 测量系统分析 动态不确定度 精度损失函数
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测量系统不确定度分析及其动态性研究 被引量:34
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作者 谢少锋 陈晓怀 张勇斌 《计量学报》 CSCD 北大核心 2002年第3期237-240,共4页
将不确定度原理引入测量系统分析 ,并对测量系统不确定度的动态性进行探讨研究 ,提出了基于灰色模型。
关键词 测量系统 不确定度分析 动态性 动态不确定度 精度损失函数 灰色模型 时序分析 神经网络
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Investigation on Non-covalent Complexes of Cyclodextrins with Li+ in Gas Phase by Mass Spectrometry
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作者 何小丹 魏王慧 +2 位作者 储艳秋 刘智攀 丁传凡 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2013年第3期287-294,I0003,共9页
To investigate the non-covalent interaction between cyclodextrins (CD) and lithium ion, a stoichiometry of α-CD, β-CD, heptakis(2,6-di-O-methyl)-β-CD (DM-β-CD), or heptakis(2,3,6-tri-O-methyl)-β-CD (TM-... To investigate the non-covalent interaction between cyclodextrins (CD) and lithium ion, a stoichiometry of α-CD, β-CD, heptakis(2,6-di-O-methyl)-β-CD (DM-β-CD), or heptakis(2,3,6-tri-O-methyl)-β-CD (TM-β-CD) was mixed with lithium salt, respectively, and then incubated at room temperature for 10 min to reach the equilibrium. In posi- tive mode, the electrospray ionization mass spectrometry (ESI-MS) results demonstrated that lithium ion can conjugate to α-, β-, DM-β- or TM-β-CD and form 1:1 stoichiometric non-covalent complexes. The binding of the complexes was further confirmed by collision- induced dissociation. The dissociation constants Kdl of four complexes (Li+α-CD, Li+β- CD, Li+DM-β-CD, and Li+TM-β-CD) were determined by mass spectrometric titration. The results showed Kdl were 18.7, 26.7, 33.6, 30.5 μmol/L for the complexes of Li+ with α-CD, β-CD, DM-β-CD, and TM-β-CD, respectively. Kdl for the Li+ complexes of/3-CD is smaller than that of DM-β-CD due to its steric effect of the partial substituted -CH3. The Kdl for the Li+ complexes of DM-β-CD is nearly in agreement with that of TM-β-CD, indicating Li+ is more likely to locate in the small rim of DM-β-CD's hydrophobic cavity. The DFT results showed through electrostatic interaction, one Li+ can strongly conjugate to four neighboring oxygen atoms. For the (α-CD+Li)+ complex, one Li+ may also situate the small rim of α-CD's hydrophobic cavity to form a non-specific host-guest complex. 展开更多
关键词 Non-covalent complex Lithium ion CYCLODEXTRIN Dissociation constant MASSSPECTROMETRY Density functional theory calculation
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A strip thickness prediction method of hot rolling based on D_S information reconstruction 被引量:1
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作者 孙丽杰 邵诚 张利 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第6期2192-2200,共9页
To improve prediction accuracy of strip thickness in hot rolling, a kind of Dempster/Shafer(D_S) information reconstitution prediction method(DSIRPM) was presented. DSIRPM basically consisted of three steps to impleme... To improve prediction accuracy of strip thickness in hot rolling, a kind of Dempster/Shafer(D_S) information reconstitution prediction method(DSIRPM) was presented. DSIRPM basically consisted of three steps to implement the prediction of strip thickness. Firstly, iba Analyzer was employed to analyze the periodicity of hot rolling and find three sensitive parameters to strip thickness, which were used to undertake polynomial curve fitting prediction based on least square respectively, and preliminary prediction results were obtained. Then, D_S evidence theory was used to reconstruct the prediction results under different parameters, in which basic probability assignment(BPA) was the key and the proposed contribution rate calculated using grey relational degree was regarded as BPA, which realizes BPA selection objectively. Finally, from this distribution, future strip thickness trend was inferred. Experimental results clearly show the improved prediction accuracy and stability compared with other prediction models, such as GM(1,1) and the weighted average prediction model. 展开更多
关键词 grey relational degree GM(1 1) model Dempster/Shafer (D_S) method least square method thickness prediction
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Basis Sets Dependency in Constructing Spectroscopy-Accuracy Ab Initio Global Electric Dipole Moment Functions
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作者 Yu Zhai Hui Li 《Chinese Journal of Chemical Physics》 SCIE EI CAS CSCD 2022年第1期52-57,I0062,共7页
Recently,more attention have been paid on the construction of dipole moment functions(DMF)using theoretical methods.However,the computational methods to construct DMFs are not validated as much as those for potential ... Recently,more attention have been paid on the construction of dipole moment functions(DMF)using theoretical methods.However,the computational methods to construct DMFs are not validated as much as those for potential energy surfaces do.In this letter,using Ar…He as an example,we tested how spectroscopyaccuracy DMFs can be constructed using ab initio methods.We especially focused on the basis set dependency in this scenario,i.e.,the convergence of DMF with the sizes of basis sets,basis set superposition error,and mid-bond functions.We also tested the explicitly correlated method,which converges with smaller basis sets than the conventional methods do.This work can serve as a pictorial sample of all these computational technologies behaving in the context of constructing DMFs. 展开更多
关键词 Dipole moment function Ab initio computation High-accuracy computation Basis set
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Average Channel Capacity of Composite κ-μ/Gamma Fading Channels
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作者 张令文 章嘉懿 刘留 《China Communications》 SCIE CSCD 2013年第6期28-34,共7页
A new analytical expression is presented for the instantaneous power Probability Density Function (PDF) of receiver signals over composite K-u/gamma fading channels. Moreover, the exact expression of channel capacit... A new analytical expression is presented for the instantaneous power Probability Density Function (PDF) of receiver signals over composite K-u/gamma fading channels. Moreover, the exact expression of channel capacity is derived in the form of an infinite series, while an accurate approximation expression is obtained in closed form. To reveal the implications of the model parameters on capacity, we provide an expression for the case of a high-SNR environment. The relationship of the presented results with previously reported results on generalised-K and K fading channels is also discussed. Finally, numerical and simulation results are presented to prove the correctness of our derived expressions. 展开更多
关键词 Shannon capacity composite fading Gauss Legendre quadrature polynomial approximation
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Predicting coal mining faults using combined rock relationships
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作者 SUN Hong-quan BAO Si-yuan +1 位作者 LI Lin LIAO Tai-ping 《Mining Science and Technology》 EI CAS 2009年第6期745-749,共5页
By studying different compressive strengths and changes in the characteristics of rocks,five variables were selected to predict faults in coal mines. Drillholes in the mined area were divided into two populations, i.e... By studying different compressive strengths and changes in the characteristics of rocks,five variables were selected to predict faults in coal mines. Drillholes in the mined area were divided into two populations, i.e., drillholes containing faults and drillholes without faults. Discriminant functions were established from the values of the five variables using Fisher's approach. Drillholes in the non-mined areas were allocated to one of the two populations by using discriminant functions. The terrenes of each drillhole were divided into 10 sections, above and below a minable coal seam. Each section has 10 layers of rocks. The population to which each drillhole in a section belongs is sorted out and the probability of each drillhole with faults obtained,i.e., a contour map of predicting the probability of faults in coal mining is shown. A comparison with the real distribution of faults shows that the precision of accurately predicting faults is greater than 70 per cent. 展开更多
关键词 GEOSTATISTICS discriminant analyses terrain combination mine fault prediction isoline map of probability
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Selection of a Minimal Complexity of a Transformation Functions of Pressure Sensors with a Maintained Given Measurement Accuracy
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作者 Ekaterina Lapina Andrey Lapin 《Journal of Mechanics Engineering and Automation》 2015年第10期585-590,共6页
For series manufacture of pressure sensors, stage of technological tests is performed, related to a definition of the manufacturing accuracy of the sensors. Technological test plan of pressure sensors involves testing... For series manufacture of pressure sensors, stage of technological tests is performed, related to a definition of the manufacturing accuracy of the sensors. Technological test plan of pressure sensors involves testing the sensors on certain fixed temperature and pressure points available in the table. According to a test results, we determine transformation function mathematical model coefficients of sensors and accordance by the claimed accuracy class, of the manufactured sensors. The cost of pressure sensors mostly depends on the cost of this step and determined by the complexity of the used transformation function model. The analysis of a contemporary works associated with the choice of transformation functions for smart pressure sensors. A new proposed indicator of model complexity of a sensor transformation function. In details shown features of the complexity indicator use and given an example. In the article was set and resolved the task to reduce the cost of the tests for commercially available sensors, by reducing the number of temperature points, without compromising the accuracy of the sensor measurement ability. 展开更多
关键词 Pressure transducers (sensors) transformation function smart pressure sensors function of a minimal complexity PRESSURE measurement accuracy.
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Classification of hyperspectral remote sensing images using frequency spectrum similarity 被引量:10
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作者 WANG Ke GU XingFa +3 位作者 YU Tao MENG QingYan ZHAO LiMin FENG Li 《Science China(Technological Sciences)》 SCIE EI CAS 2013年第4期980-988,共9页
An algorithm of hyperspectral remote sensing images classification is proposed based on the frequency spectrum of spectral signature.The spectral signature of each pixel in the hyperspectral image is taken as a discre... An algorithm of hyperspectral remote sensing images classification is proposed based on the frequency spectrum of spectral signature.The spectral signature of each pixel in the hyperspectral image is taken as a discrete signal,and the frequency spectrum is obtained using discrete Fourier transform.The discrepancy of frequency spectrum between ground objects' spectral signatures is visible,thus the difference between frequency spectra of reference and target spectral signature is used to measure the spectral similarity.Canberra distance is introduced to increase the contribution from higher frequency components.Then,the number of harmonics involved in the proposed algorithm is determined after analyzing the frequency spectrum energy cumulative distribution function of ground object.In order to evaluate the performance of the proposed algorithm,two hyperspectral remote sensing images are adopted as experimental data.The proposed algorithm is compared with spectral angle mapper (SAM),spectral information divergence (SID) and Euclidean distance (ED) using the product accuracy,user accuracy,overall accuracy,average accuracy and Kappa coefficient.The results show that the proposed algorithm can be applied to hyperspectral image classification effectively. 展开更多
关键词 hyperspectral image spectral similarity frequency spectrum feature remote sensing CLASSIFICATION
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HF SAR image cross-correlation technique for high accuracy orbit positioning
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作者 KOBAYASHI Takao LEE SeungRyeol +1 位作者 KIM JungHo ONO Takayuki 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2011年第5期978-985,共8页
A novel technique to determine the position of spacecraft orbits is proposed. The technique is based on the cross-correlation function of HF SAR images and is able to determine the relative position of orbits with an ... A novel technique to determine the position of spacecraft orbits is proposed. The technique is based on the cross-correlation function of HF SAR images and is able to determine the relative position of orbits with an accuracy of - λ/4 or better, where 2 is the wavelength of the HF radar pulse at its center frequency. The performance of the proposed technique was confirmed by simulation which was carried out under the condition of design facts of the SELENE LRS mission. The highly accurate orbit positioning enables precise superposition of HF SAR images so that the inherent mirror image ambiguity problem of HF SAR imaging is resolved to obtain a quality SAR image of the HF band. In addition ambitious 2D-SAR processing would be possible when the above accuracy is available. 展开更多
关键词 high accuracy orbit determination SAR LRS SELENE
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