生物大分子缔合反应中声子熵的研究     

何安明  王梦飞 《地球科学与环境学报》1998,20(2):4

采用量子统计方法,得到了声子熵的计算公式和初步结果,同时还指出在胰岛素与其受体的缔合反应中,声学支声子所提供的声子熵起了重要作用。这样不仅满意地解释了实验结果,同时也阐释了生物体发出红外辐射的原因。  相似文献   

基于离散粒子群算法的2种新型水体提取方法的对比与验证     

李志红  李旺平  王玉  陈璐  郁林  周兆叶  郝君明  吴晓东  李传华 《地球信息科学学报》2021,23(6):1106-1117

随着遥感技术在水体提取与监测方面的广泛应用,更多的研究者致力于提高遥感水体提取的精度。离散粒子群算法在遥感图像分类研究中获得了较高的精度和更稳健的分类效果,已经被应用到遥感水体提取领域,但其在水体提取中的适用性和精度还有待对比与验证。本文采用最新提出的2种基于离散粒子群算法的水体提取方法,即光谱匹配耦合离散粒子群算法（SMDPSO）与最大熵耦合离散粒子群算法（MEDPSO）,基于Landsat8_OLI遥感影像,分别选择了有冰雪、有云、有山体阴影和有建筑物的4种环境复杂,常规方法提取精度较低的区域进行水体提取,并与2种常用的水体指数法（NDWI、MNDWI）进行了对比与验证。结果表明：① SMDPSO和MEDPSO方法在4个实验区都能快速地寻找出最佳的水体分布,具有一定的通用性;NDWI和MNDWI方法对有冰雪、有云、有山体阴影和有建筑物影响的区域表现出水体信息的错分现象,提取精度较低;② SMDPSO方法能够识别细小河流和离散水体,水体提取精度较高,但在有冰雪、云、山体阴影和建筑物的复杂环境下提取精度较低、误判率高;MEDPSO方法不仅可以识别细小水体,而且也解决了其他3种方法在提取过程中无法抑制背景信息干扰的问题,在4个实验区的总体精度均在97.8%以上,高于其他3种方法;③ 将离散粒子群算法引入到水体提取方法之中,可增强方法的区域整体性,也可提高其水体提取的精度和自动化程度;④ 运用最大熵模型等机器学习方法,可以结合光谱、形状和纹理等影像信息以及地形信息来进行水体识别,使得水体信息提取精度更高。本文的研究可为离散粒子群算法的推广以及遥感水体提取方法的选择提供参考。  相似文献   

变分模态分解结合样本熵的变形监测数据降噪     

鲁铁定  谢建雄 《大地测量与地球动力学》2021,41(1):1-6

针对变形监测数据中包含的噪声成分难以有效滤除,导致预测结果精度不理想的问题,提出一种应用于变形监测领域的新降噪方法。首先利用变分模态分解（VMD）将原始监测序列分解为k个不同中心频率的带限固有模态函数（BIMF）,再将样本熵（SE）大于设定阈值的高频BIMF作为噪声成分剔除,最后重构余下的BIMF获得降噪序列。仿真算例和工程实例检验的结果表明,新方法与EEMD及CEEMD方法相比各评价指标均为最优,降噪结果可为形变分析和预测提供可靠依据。  相似文献   

矿井涌水量时间序列混沌特性的Kolmogorov熵判别          下载免费PDF全文

肖江  连生土  唐依民  张焕英 《地学前缘》2010,17(6):187-191

根据相空间重构理论和技术以及G-P算法,在嵌入维按等间隔m不断增加的情况下,在无标度区间内,作等斜率线性回归,利用最小二乘法得到6个典型矿区矿井涌水量时间序列的Kolmogorov熵。结果表明其具有混沌特性,从而可为确定矿区地下水系统特征、性质和矿井涌水量预测模式提供理论依据。  相似文献   

二种地震频谱分析方法的比较          下载免费PDF全文

许康生 《地震工程学报》2000,22(3):346-347

利用最大熵谱法和快速傅里叶变换分别对天祝地震序列频谱进行了分析,并对分析结果进行了比较,结果表明,上述２种方法对于提取地震波中的有用信息都是有效的,可靠的,最大熵谱法的分辨率较高,傅里叶变换分辨率较低,但使用简单、方便。  相似文献   

On Subdiurnal Effects in Earth Rotation     

Arfa-Kaboodvand  K.  Groten  E. 《Studia Geophysica et Geodaetica》1999,43(3):275-283

More than two years of almost continuous polar motion data (obtained by reprocessing GPS-Observations) have been used to analyse the daily/subdaily variations in Earth rotation based on the complex Wavelet-Technique. Systematic and spectral analytical investigations of the degree of variability of periods including tidal have been carried out. Relevant indications of oceanic effects, besides atmospheric components, have been observed.  相似文献   

Optimal Spatial Sampling Design in a Multivariate Framework   总被引：2，自引：0，他引：2  

M. C. Bueso  J. M. Angulo  J. Cruz-Sanjulián  J. L. García-Aróstegui 《Mathematical Geology》1999,31(5):507-525

The problem of spatial sampling design for estimating a multivariate random field from information obtained by sampling related variables is considered. A formulation assigning different degrees of importance to the variables and locations involved is introduced. Adopting an entropy-based approach, an objective function is defined as a linear combination in terms of the amount of information on the variables and/or the locations of interest contained in the data. In the multivariate Gaussian case, the objective function is obtained as a geometric mean of conditional covariance matrices. The effect of varying the degrees of importance for the variables and/or the locations of interest is illustrated in some numerical examples.  相似文献   

Reconstruction of Nonlinear Geochemical Dynamics of Elemental Sedimentation Based on Power Spectral Analysis of Time Sequence   总被引：2，自引：0，他引：2  

Yongzhang Zhou 《Mathematical Geology》1999,31(6):723-742

Maximum entropy spectral analysis and multidimensional cross-spectral analysis are two important tools for studying periodicity of elemental sedimentation in strata. They are applied to the study of the Devonian lensoid limestone formation in the Nandan-Hechi basin of Guangxi, China. Results show that all major element oxides of the sedimentary formation display a consistent change period of about 4 m; however, elements do not change in step. Nonlinear geochemical dynamic processes of elemental sedimentation through sea-floor fluids may be effectively reconstructed based on power spectral analyses.  相似文献   

On Probing the Inertial Subrange     

Katja Henjes 《Boundary-Layer Meteorology》1999,91(3):367-384

For an extensive turbulent wind speed data set collected on the open ocean, the optimum sampling time is determined to calculate inertial-range spectra. Such spectra are widely used to estimate surface fluxes. The optimum sampling time corresponds to the turbulent memory time, the minimum period after which a given time series can be interpreted as a new independent measurement. In our case, this interval is found to be only about six seconds.Separate spectral levels are calculated from the three measured vector components of the wind. Their ratios are compatible with the assumption of an isotropic inertial subrange, but scatter considerably. Alignment factors are developed based on Kolmogorov's theory, and the aligned spectral levels coincide within a few percent. It is proposed that alignment might be a more reliable test than the ratio of the spectral levels to determine whether observations have taken place in a universal inertial subrange. It is recommended that all three wind components are used to estimate the dissipation rate.  相似文献   

不同下垫面大气边界层湍流的混沌特性研究   总被引：2，自引：0，他引：2  

高志球  苏中波  王介民  甄广炬 《南京气象学院学报》1999,22(4):680-684

根据３ 种不同观测资料,计算和分析了有关诊断具有耗散结构的系统混沌运动的特征量：功率谱、关联维数、Ｌｙａｐｕｎｏｖ 指数和关联熵。结果表明：尽管下垫面明显不同,大气边界层湍流均为混沌运动。  相似文献