共查询到20条相似文献，搜索用时 62 毫秒
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基于小波变换和支持向量机的大坝变形预测 总被引：2，自引：0，他引：2
提出了一种基于小波变换和支持向量机的大坝变形预测方法.通过小波变换把变形时间序列分解成具有不同频率特征的分量,根据各分量的特点构造不同的支持向量机模型进行预测,然后把各分量的预测结果进行重构,作为最终的变形预测结果.实例证明,该方法具有很高的预测精度和较强的泛化能力. 相似文献
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由于受到温度、雨水冲刷等外在因素的影响,大坝变形时间序列数据会呈现出非线性和非平稳的曲线特性。为此,提出一种经验模态分解(EMD)和最小二乘支持向量机(LSSVM)相结合的大坝变形预测模型。首先,使用EMD对大坝变形时间序列数据分解成若干个不同尺度的本征模式分量(IMF);然后,利用LSSVM模型对各个IMF进行预测;最后,对预测的结果相加得到大坝变形预测值。以吉林市丰满大坝为算例,构建EMD-LSSVM预测模型,并与LSSVM模型对比分析,结果表明,EMD-LSSVM模型预测效果更好,精度更高,具有更好的实用型。 相似文献
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基于相空间重构与支持向量机预测滑坡位移的一种新方法 总被引：1，自引：0，他引：1
提出了一种基于相空间重构与支持向量机预测滑坡位移的新方法.首先,以滑坡位移时间序列的混沌特性为基础,对其应用互信息法计算最优时间延迟;然后,利用小波变换对滑坡位移序列数据进行频域分解,应用Cao氏方法对分解后的每个分量序列分别计算其最佳嵌入维数,在此基础上,对各个分量序列进行相空间重构,利用支持向量机对每个分量单独进行建模预测;最后,将各分量预测结果进行小波重构,得到最终预测结果.实例证明,该方法可以在滑坡位移预测中获得有效的应用. 相似文献
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论述了支持向量机的回归算法和基于时间序列支持向量回归的建筑物变形预测方法,并用MATLAB6.5工具箱编制基于时间序列支持向量回归程序,建立了基于时间序列支持向量回归模型。最后以实例数据讨证基于时间序列支持向量机回归模型的预测方法。研究表明:用时间序列支持向量回归模型建立的建筑物变形监测的预测模型是可行的和有效的。 相似文献
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针对大坝变形系统的非线性、复杂性以及不确定等特点,提出一种优化多核相关向量机的大坝变形预测模型方法。通过对实验数据进行归一化处理,核函数的加权组合以及遗传算法对模型参数的优化,建立遗传算法优化多核相关向量机的大坝变形预测模型。实验结果表明:数据归一化能归纳统一样本的统计分布性,加快梯度下降求解最优解速度和提高预测精度;优化的加权核函数能有效提高模型预测精度;各项精度指标值均优于BP神经网络方法、多项式核相关向量机方法预测精度,证实优化的多核相关向量机模型是一种精度较高的大坝变形预测方法。 相似文献
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针对大坝变形预测中非平稳性且含噪声的数据处理问题,该文提出一种基于剔除含噪声信号的大坝变形傅里叶(Fourier)预测新算法。首先利用经验模态分解(EMD)法将变形时间序列分解成具有不同尺度特征的固有模态函数(IMF)分量,并计算出各分量与原始信号的相关系数;然后根据相关系数剔除含噪声的IMF分量,并采用游程判定法对剩余的波动程度相似或相同的分量进行信号重构;最后利用傅里叶函数对重构后的分量进行曲线拟合,并据此构建大坝变形预测模型,对出现的模型系数采用最小二乘算法求解。经算例验证,并与GM(1,1)、BP神经网络和傅里叶模型对比分析,结果表明该文算法预测精度较高,可用于大坝的变形预测。 相似文献
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采用Landsat TM数据分析了阿克苏河—塔里木河断面水质污染状况,通过波段的DN值和常规监测数据建立能反映水质状况的
污染物监测模型。结果发现,将2000年常规监测数据代入模型后,与遥感数据的结果基本吻合| 重建阿克苏河—塔里木河的连续水体
污染变化曲线,得出污染物浓度随着远离上游而增加。 相似文献
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Monitoring drought dynamics in the Aravalli region (India) using different indices based on ground and remote sensing data 总被引：5，自引：0，他引：5
C. Bhuiyan R.P. Singh F.N. Kogan 《International Journal of Applied Earth Observation and Geoinformation》2006,8(4):289-302
The hard-rock hilly Aravalli terrain of Rajasthan province of India suffers with frequent drought due to poor and delayed monsoon, abnormally high summer-temperature and insufficient water resources. In the present study, detailed analysis of meteorological and hydrological data of the Aravalli region has been carried out for the years 1984–2003. Standardised Precipitation Index (SPI) has been used to quantify the precipitation deficit. Standardised Water-Level Index (SWI) has been developed to assess ground-water recharge-deficit. Vegetative drought indices like Vegetation Condition Index (VCI) and Temperature Condition Index (TCI) and Vegetation Health Index (VHI) have been computed using NDVI values obtained from Global Vegetation Index (GVI) and thermal channel data of NOAA AVHRR satellite. Detailed analyses of spatial and temporal drought dynamics during monsoon and non-monsoon seasons have been carried out through drought index maps generated in Geographic Information Systems (GIS) environment. Analysis and interpretation of these maps reveal that negative SPI anomalies not always correspond to drought. In the Aravalli region, aquifer-stress shifts its position time to time, and in certain pockets it is more frequent. In comparison to hydrological stress, vegetative stress in the Aravalli region is found to be slower to begin but quicker to withdraw. 相似文献
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Piyoosh Rautela Ramesh Chandra Lakhera 《International Journal of Applied Earth Observation and Geoinformation》2000,2(3-4)
The area around Sataun in the Sirmur district of Himachal Pradesh, India (falling between the rivers Giri and Tons; both tributaries of the Yamuna River) was studied for landslide vulnerability on behalf of the inhabitants. The study was made using extensive remote sensing data (satellite and airborne). It is well supported by field evidence, demographic and infrastructural details and aided by Geographic Information System (GIS) based techniques. Field observations testify that slope, aspect, geology, tectonic planes, drainage, and land use all influence landslides in the region. These parameters were taken into consideration using the statistical approach of landslide hazard zonation. Using the census data of 1991, vulnerability of the populace to the landslide hazard was accessed. As most of the infrastructure in the region is concentrated around population centres, population data alone was used for vulnerability studies. 相似文献
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ZHAN F. Benjamin 《地球空间信息科学学报》2011,(1)
Although it is well known that coseismic gravity changes take place during an earthquake, previous research has not yielded convincing evidence demonstrating that significant gravity changes occur before large earthquakes. Furthermore, even if we suspect that gravity changes occur before large earthquakes, we have yet to demonstrate how to consistently observe these changes for useful earthquake forecast that would bring benefits to society. We analyzed ground gravity survey data obtained in 1998, 2000, 200... 相似文献
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GNSS系统及其技术的发展研究 总被引：3，自引：1，他引：2
阐述了国际上卫星导航系统的总体发展,对美、俄、欧、中的四大全球系统,以及相关的区域系统和增强系统进行了简单的介绍,研究分析了GNSS系统及其技术的发展趋势,同时分析了我国Compass全球系统面临的机遇和挑战,并提出了我国未来工作的建议. 相似文献
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“4D”技术及其应用 总被引：13，自引：0，他引：13
介绍“４Ｄ”（即数字地面模型、数字正射影像、数字栅格地图和数字线划地图）系列产品的生产流程、关键技术、及其在耕地保护、防灾减灾救灾和城市规划等方面的应用方法。 相似文献
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《International Journal of Digital Earth》2013,6(1):66-87
Abstract Virtual Australia is not a well-defined or agreed concept. This discussion paper conceptualises Virtual Australia as a ‘virtual [digital] model containing and representing all non-trivial objects and their contextual environment – from blue sky to bedrock – in real world Australia’. It describes a scenario for Virtual Australia, one or two decades from now, in which the locations and conditions of non-trivial objects and their environment are updated automatically through a combination of remote sensing and wireless communication technologies in support of a ‘Supranet’. It then examines the concept of the ‘Supranet’ – a pervasive information network based largely on wireless technology linking the physical world to a virtual model in real time – and develops and discusses three principal characteristics of the Supranet: the ability to have or collect specific information (know); the ability to process information (think); and the ability to communicate that information. If, in the near future, any or all non-trivial devices are to some extent able to know, think and communicate, the potential for object autonomy will be realised. 相似文献
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自动车辆定位导航系统中传感器的误差分析 总被引：1，自引：0，他引：1
对国界定位导航系统中几种常见的辅助传感器所产生的误差进行了分析，导出了不同传感器的误差模型。这些误差模型是估计车辆位置的扩展卡尔曼滤波器的基础，同时也为选择适当的传感器提供了理论根据。 相似文献