Support vector regression （SVR） method is a novel type of learning machine algorithms, which is seldom applied to the development of urban atmospheric quality models under multiple socio-economic factors. This study...Support vector regression （SVR） method is a novel type of learning machine algorithms, which is seldom applied to the development of urban atmospheric quality models under multiple socio-economic factors. This study presents four SVR models by selecting linear, radial basis, spline, and polynomial functions as kernels, respectively for the prediction of urban dust fall levels. The inputs of the models are identified as industrial coal consumption, population density, traffic flow coefficient, and shopping density coefficient. The training and testing results show that the SVR model with radial basis kernel performs better than the other three both in the training and testing processes. In addition, a number of scenario analyses reveal that the most suitable parameters （insensitive loss function e, the parameter to reduce the influence of error C, and discrete level or average distribution of parameters σ） are 0.001, 0.5, and 2 000, respectively.展开更多
针对室内可见光定位中非视距信道(Non Line of Sight,NLOS)导致定位精度不足的问题,提出了一种基于动态高斯加权(Dynamic Gaussian Weighted,DGW)接收信号强度指示(Received Signal Strength Indicator,RSSI)和遗传算法(Genetic Algorit...针对室内可见光定位中非视距信道(Non Line of Sight,NLOS)导致定位精度不足的问题,提出了一种基于动态高斯加权(Dynamic Gaussian Weighted,DGW)接收信号强度指示(Received Signal Strength Indicator,RSSI)和遗传算法(Genetic Algorithm,GA)改进支持向量回归(Support Vector Regression,SVR)的室内可见光定位算法。首先,构建指纹库并划分数据集,计算接收器与光源之间的距离动态调整高斯函数的标准差,再结合RSSI信号的波动性进行自适应加权,以减少NLOS对定位的影响。然后,使用GA优化SVR模型的参数,得到最佳定位模型。最后,使用最佳定位模型对加权后的指纹数据进行定位预测。实验结果表明:本算法的平均定位误差为7.1 cm,相较于SVR、SVR-GA等算法降低了21.1%~42.3%,并且能有效降低NLOS的影响、提高室内定位的精度,具有较强的应用前景。展开更多
针对云服务器中存在软件老化现象,将造成系统性能衰退与可靠性下降问题,借鉴剩余使用寿命(Remaining useful life,RUL)概念,提出基于支持向量和高斯函数拟合(Support vectors and Gaussian function fitting,SVs-GFF)的老化预测方法.首...针对云服务器中存在软件老化现象,将造成系统性能衰退与可靠性下降问题,借鉴剩余使用寿命(Remaining useful life,RUL)概念,提出基于支持向量和高斯函数拟合(Support vectors and Gaussian function fitting,SVs-GFF)的老化预测方法.首先,提取云服务器老化数据的统计特征指标,并采用支持向量回归(Support vector regression,SVR)对统计特征指标进行数据稀疏化处理,得到支持向量(Support vectors,SVs)序列数据;然后,建立基于密度聚类的高斯函数拟合(Gaussian function fitting,GFF)模型,对不同核函数下的支持向量序列数据进行老化曲线拟合,并采用Fréchet距离优化算法选取最优老化曲线;最后,基于最优老化曲线,评估系统到达老化阈值前的RUL,以预测系统何时发生老化.在OpenStack云服务器4个老化数据集上的实验结果表明,基于RUL和SVs-GFF的云服务器老化预测方法与传统预测方法相比,具有更高的预测精度和更快的收敛速度.展开更多
基金Projects(2007JT3018, 2008JT1013, 2009FJ4056) supported by the Key Project in Hunan Science and Technology Program, ChinaProject(20090161120014) supported by the New Teachers Sustentation Fund in Doctoral Program, Ministry of Education, China
文摘Support vector regression （SVR） method is a novel type of learning machine algorithms, which is seldom applied to the development of urban atmospheric quality models under multiple socio-economic factors. This study presents four SVR models by selecting linear, radial basis, spline, and polynomial functions as kernels, respectively for the prediction of urban dust fall levels. The inputs of the models are identified as industrial coal consumption, population density, traffic flow coefficient, and shopping density coefficient. The training and testing results show that the SVR model with radial basis kernel performs better than the other three both in the training and testing processes. In addition, a number of scenario analyses reveal that the most suitable parameters （insensitive loss function e, the parameter to reduce the influence of error C, and discrete level or average distribution of parameters σ） are 0.001, 0.5, and 2 000, respectively.
文摘针对室内可见光定位中非视距信道(Non Line of Sight,NLOS)导致定位精度不足的问题,提出了一种基于动态高斯加权(Dynamic Gaussian Weighted,DGW)接收信号强度指示(Received Signal Strength Indicator,RSSI)和遗传算法(Genetic Algorithm,GA)改进支持向量回归(Support Vector Regression,SVR)的室内可见光定位算法。首先,构建指纹库并划分数据集,计算接收器与光源之间的距离动态调整高斯函数的标准差,再结合RSSI信号的波动性进行自适应加权,以减少NLOS对定位的影响。然后,使用GA优化SVR模型的参数,得到最佳定位模型。最后,使用最佳定位模型对加权后的指纹数据进行定位预测。实验结果表明:本算法的平均定位误差为7.1 cm,相较于SVR、SVR-GA等算法降低了21.1%~42.3%,并且能有效降低NLOS的影响、提高室内定位的精度,具有较强的应用前景。
文摘针对云服务器中存在软件老化现象,将造成系统性能衰退与可靠性下降问题,借鉴剩余使用寿命(Remaining useful life,RUL)概念,提出基于支持向量和高斯函数拟合(Support vectors and Gaussian function fitting,SVs-GFF)的老化预测方法.首先,提取云服务器老化数据的统计特征指标,并采用支持向量回归(Support vector regression,SVR)对统计特征指标进行数据稀疏化处理,得到支持向量(Support vectors,SVs)序列数据;然后,建立基于密度聚类的高斯函数拟合(Gaussian function fitting,GFF)模型,对不同核函数下的支持向量序列数据进行老化曲线拟合,并采用Fréchet距离优化算法选取最优老化曲线;最后,基于最优老化曲线,评估系统到达老化阈值前的RUL,以预测系统何时发生老化.在OpenStack云服务器4个老化数据集上的实验结果表明,基于RUL和SVs-GFF的云服务器老化预测方法与传统预测方法相比,具有更高的预测精度和更快的收敛速度.
