移动最小二乘支持向量机

基于移动最小二乘逐点逼近思想,移动权被引入到最小二乘支持向量机的误差变量中,得到新算法的模型.此外,证明了用移动最小二乘支持向量机作函数估计与在特征空间中用移动最小二乘法得到的解是一致的,揭示了移动最小二乘支持向量机所选择的核函数相当于移动最小二乘法所选择基函数组.数值试验与实例进一步验证所提出方法的优越性.     

最小二乘支持向量机在热舒适性PMV指标预测中的应用研究

介绍了一种新型的机器学习算法一最小二乘支持向量机的原理，并针对预测PMV指标建立了最小二乘支持向量机预测模型。该模型的预测结果表明，最小二乘支持向量机预测准确度高，计算过程速度快，可以满足以PMV指标作为被控参数的空调系统控制的要求。     

最小二乘支持向量机的扩展及其在时间序列预测中的应用

根据时间序列近期数据较远期数据包含有更多未来信息的思想,对最小二乘支持向量机预测方法进行了扩展,得到了更具一般性的最小二乘支持向量机预测模型,给出了扩展后的预测模型具体算法。两个时间序列的预测实例表明,扩展后的预测方法获得了更好的预测效果,提升了最小二乘支持向量机预测方法的价值。     

基于最小二乘支持向量机的传感器动态补偿方法

介绍和比较标准支持向量机（SVM）和最小二乘支持向量机（LS-SVM）基本原理的基础上,探讨了一种利用LS-SVM进行传感器动态误差补偿的方法,并给出了相应的过程和算法。与标准SVM补偿方法比较,该方法的优点是明显的：用等式约束代替标准SVM算法中的不等式约束,将求解二次规划问题转化为直接求解线性矩阵方程,在相同样本条件下,使得补偿器构造速度提高1～2个数量级。通过对SVM和LS-SVM传感器动态补偿的仿真分析和实验结果对比表明,在噪声条件下,LS-SVM方法的补偿误差约为SVM的40％。因此,LS-SVM补偿方法学习速度快,抗噪声干扰能力强,更适合传感器动态补偿。     

基于最小二乘支持向量机的扫描仪特征化

目的基于最小二乘支持向量机回归(LSSVR),研究扫描仪图像输入设备的特征化方法。方法以ColorChecker SG标准色卡为目标,通过最小二乘支持向量机建立RGB三通道值到CIE Lab色度值的非线性映射模型,采用基于交叉验证的网格搜索确定模型最优参数,优化LSSVR模型,实现彩色扫描仪的色度特征化。结果所建模型的训练集R-squared为0.996,验证集R-squared为0.998,训练集与验证集的CIEDE2000平均色差分别为1.1463,1.2754。结论 LSSVR模型能够较好地实现彩色扫描仪色度特征化,泛化能力较强,此模型可有效地提高彩色扫描仪特征化的精度且计算处理速度更快。     

序贯最小二乘支持向量机的结构系统识别

提出一种用于结构系统识别的序贯最小二乘支持向量机（SLS-SVM）方法,通过对训练数据的序列进入和数据缩减,分别采用增量算法和减缩修剪算法有效地改进了LS-SVM.这种方法克服了标准LS-SVM算法的稀疏性缺失的缺点,并使LS-SVM的序贯训练成为可能.对非线性滞迟结构的在线参数识别显示了所提出方法的鲁棒性和高效率,同时也表明SLS-SVM算法的速度比批处理SVM算法要快.     

基于最小二乘支持向量机的传感器非线性动态系统辨识

讨论了一种基于最小二乘支持向量机的非线性动态传感器系统辨识方法,并给出了相应的推导过程和学习算法.首先,将传感器的非线性动态系统分解为静态非线性子环节和动态线性子环节串联--Hammerstein模型;然后,建立类似线性的中间模型,通过该模型能将Hammerstein模型的非线性传递函数转换为等价的类线性形式;再通过LS-SVM线性回归算法求取中间模型参数;最后推导出中间模型参数与Hammerstein模型参数之间的关系,并通过该关系反演出原传感器系统的Hammerstein模型参数,实现传感器非线性动态辨识.仿真与实际传感器系统辨识的实验结果均表明该方法可行.     

基于形态优化滤波和最小二乘支持向量机的轴承故障分析

为实现滚动轴承故障分析,提出基于形态优化滤波和最小二乘支持向量机的轴承故障分析方法。首先,通过判别指标最大化原则确定最佳形态滤波算子;然后,用最佳形态滤波算子对滚动轴承实例故障信号进行降噪分析;最后,利用粒子群对模型参数进行寻优,利用最小二乘支持向量机建立轴承故障分析模型,并对模型效果进行评价。实验结果表明:该方法从模型稳定性、预测准确度、模型复杂度3个方面考虑,故障分析结果较优,能够更好地提取轴承故障特征信息。     

最小二乘支持向量机和小波电铲供电机组状态预测

针对电铲供电机组振动时间序列是个非线性、非平稳的复杂时间序列,难以用单一预测方法进行有效预测的问题,建立了一种基于小波分解和最小二乘支持向量机混合模型进行状态预测的方法.首先通过小波分解,将原始振动时间序列分解到不同层次,然后根据分解后各层次分量的特点选择不同的嵌入维数和LS-SVM参数分别进行预测,最后重构得到原始序列的预测值.对某电铲供电机组振动趋势的预测结果表明,该模型的预测性能好于单一的支持向量机预测方法.     

基于支持向量机的多元文本分类研究

根据文本分类的特点，在对最小二乘支持向量机方法进行详细分析的基础上，创建了基于最小二乘支持向量机的多元文本分类器．实验表明，采用该文本分类器能够在保持较高分类精度和召回率的基础上，提高训练效率，具有一定的可行性．     

西安市冬季办公建筑和商场室内热环境调查研究

于2010年1月对西安市5栋办公楼和3栋商场的冬季采暖系统进行调查,测试了建筑室内温湿度等参数,并对室内人员热舒适情况进行了问卷调查。调研结果表明：被调查建筑内热源形式主要为市政蒸汽和燃气锅炉;冬季办公楼和商场内平均空气温度分别为19.9℃和21.1℃,满足热舒适空调的要求,但是商场内平均温度偏高,不符合建筑节能的要求;而两种类型建筑内平均空气相对湿度都要低于30%,空气较干燥。通过问卷调查统计得到办公楼和商场内人们的热感觉、热舒适以及满意程度百分率分布情况,都有高于83%的人感觉满意和刚好满意,满意程度都较高。进一步地分析得到办公楼和商场内实际热中性温度分别为18.8℃和18.7℃,并获得了对应的能被80%的人所接受的热舒适温度范围。     

热环境客观评价的一种简易方法

针对范格(Fanger)提出的预测平均热反应指标PMV(PredictedMeanVote)难以计算的不足,提出了一个基于热平衡的无因次数HB(HeatBalance),它反映了人体的显热散热量与总产热量之比,包含影响热感觉的5个基本参数,计算简便,而且与PMV之间存在明显的线性关系。文章推导了HB的表达式,并将HB、PMV与主观评价的结果进行了对比,给出了HB与PMV的关系式,定义了HB的热感觉标度,因此可以用于普通热环境的客观评价,也可以作为PMV的一种简易计算方法。     

室内热环境、热舒适与工作效率关系的研究

为研究室内热环境与热舒适、工作效率的关系,在镇江和上海的两个工厂采用环境参数测量和问卷方法进行了现场调查。结果表明,热舒适或热中性状态时工作效率不一定为最高,员工效率在稍微凉爽环境下达到最高。并且通过灰色分析得知,当环境温度适宜时,保持室内良好的空气品质能够使员工维持较高的工作效率。     

Application of the Transient Hot-Wire Technique to the Measurement of the Thermal Conductivity of Solids

A novel application of the transient hot-wire technique for thermal conductivity measurements is described. The new application is intended to provide an accurate means of implementation of the method to the determination of the thermal conductivity of solids exemplified by a standard reference ceramic material. The methodology makes use of a soft-solid material between the hot wires of the technique and the solid of interest. Measurements of the transient temperature rise of the wires in response to an electrical heating step in the wires over a period of 20 s to 10 s allows an absolute determination of the thermal conductivity of the solid. The method is based on a full theoretical model with equations solved by finite-element method applied to the exact geometry. The uncertainty achieved for the thermal conductivity is better than ±1%, and for the product (C _p) about ±3%. The whole measurement involves a temperature rise less than 4 K.     

A Transient Heating Technique for Measuring the Thermal Diffusivity of Metals

A transient heating technique, improving the constant-rate-heating technique for the measurements of thermal diffusivities of metals, is proposed. For a physical model of a specimen to be measured, the transient heat-conduction equation was solved with some boundary conditions, and the solution obtained was used as the principle of the present transient heating technique for determining the thermal diffusivity of the specimen. Additionally, a thermal analysis was made to satisfy a boundary condition involved in the principle, that is, the condition of radiative thermal insulation at the two end surfaces of the specimen. To verify the validity of the present technique, the thermal diffusivity of iron, whose thermophysical properties are well-known, was measured with the same apparatus as used in our previous work, and the experimental results are discussed. Moreover, thermal diffusivities of thermocouple materials, namely, constantan, chromel, and alumel, were measured by the technique in the temperature range of 360 to 680 K.     

某办公室热环境CFD模拟研究

采用Airpak软件对某办公室夏季空调环境进行了数值模拟,通过对办公室截面速度场、温度场、空气龄,以及PPD、PMV的分析研究,对办公室的热环境进行了评价。为相关系统的设计提供了参考。     

基于LS-SVM的立体视觉摄像机标定

利用最小二乘支持向量机来直接学习图像信息与三维信息之间的关系,不需确定摄像机具体的内部参数和外部参数.在双目视觉的情况下,两摄像机的位置关系不需具体求出,而是隐含在映射关系中.根据最小二乘支持向量机与摄像机标定的特点,提出了基于最小二乘支持向量机的双目立体摄像机标定方法.将摄像头采集到的图像的像素坐标作为输入,将世界坐标作为输出,用最小二乘支持向量机使网络实现给定的输入输出映射关系.该方法同BP神经网络预测结果对比表明:基于最小二乘支持向量机的双目视觉标定方法速度快,实时性好,能有效提高标定精度.     

成都地区廉租房热环境测试分析

对成都某一廉租房进行了实测,测试结果发现在成都地区夏季夜间室外气温比较凉爽,而室内却普遍闷热,即使在阴雨天也是如此。提出通过改善围护结构和通风措施来改善廉租房热环境。研究结果对于今后廉租房的建设可以提供一定的参考意义。     

Application of the Multi-Current Transient Hot-Wire Technique for Absolute Measurements of the Thermal Conductivity of Glycols

Experimental measurements of the thermal conductivity of mono-, di-, tri-, and tetra-ethylene glycol are presented. The experiments were carried out at atmospheric pressure and at temperatures ranging from 25 to 65°C. The multi-current transient hot-wire technique has been used with a platinum wire of 25 μm diameter; the electrical current varied from 25 to 75 mA. For all studied glycols, it was found that the thermal conductivity increases with temperature and decreases with the glycol molar mass. The random uncertainty of the reported experimental thermal conductivity data is less than 0.9%. The estimated systematic errors affecting the obtained data are at most 2%. The values obtained in this study were compared with previously published results for the four glycols, finding deviations of the order of 2%.     

A High-Temperature Transient Hot-Wire Thermal Conductivity Apparatus for Fluids

A new apparatus for measuring both the thermal conductivity and thermal diffusivity of fluids at temperatures from 220 to 775 K at pressures to 70 MPa is described. The instrument is based on the step-power-forced transient hot-wire technique. Two hot wires are arranged in different arms of a Wheatstone bridge such that the response of the shorter compensating wire is subtracted from the response of the primary wire. Both hot wires are 12.7 µm diameter platinum wire and are simultaneously used as electrical heat sources and as resistance thermometers. A microcomputer controls bridge nulling, applies the power pulse, monitors the bridge response, and stores the results. Performance of the instrument was verified with measurements on liquid toluene as well as argon and nitrogen gas. In particular, new data for the thermal conductivity of liquid toluene near the saturation line, between 298 and 550 K, are presented. These new data can be used to illustrate the importance of radiative heat transfer in transient hot-wire measurements. Thermal conductivity data for liquid toluene, which are corrected for radiation, are reported. The precision of the thermal conductivity data is ± 0.3% and the accuracy is about ±1%. The accuracy of the thermal diffusivity data is about ± 5%. From the measured thermal conductivity and thermal diffusivity, we can calculate the specific heat, C_p, of the fluid, provided that the density is measured, or available through an equation of state.