ε不敏感支持向量回归在化工数据建模中的应用

针对化工领域数据建模小样本、不适定性等问题，提出了一种用ε不敏感支持向量回归(ε-SVR)方法进行实际过程建模的想法，以解决人工神经网络等方法在数据建模中的“过拟合”、泛化性差等问题．在分析ε-SVR特性的基础上，用一个非线性函数逼近例子验证了ε-SVR在小样本情况下比BP前馈神经网络具有更优良的建模能力．将ε-SVR应用到丙烯腈聚合反应过程质量指标软测量混合模型中，仿真和现场运行结果表明ε-SVR是一种非常有效的化工数据建模方法．     

独立成分分析支持向量机回归模型及其在近红外光谱分析中的应用

首先采用独立成分分析(ICA)提取近红外光谱数据矩阵的独立成分和相应的混合矩阵,然后用支持向量机回归(SVR)对混合矩阵和实测浓度矩阵进行建模,建立了独立成分分析-支持向量机回归(ICA SVR)的近红外分析建模方法.结果表明,ICA SVR模型的预测结果明显优于SVR和偏最小二乘法(PLS)方法,方法用于肉样品中水分、脂肪和蛋白质的同时测定,获得了满意的结果.     

网络搜索数据和GWO-SVR模型的旅游短期客流量预测

利用皮尔森相关系数法处理网络搜索数据,用灰狼算法（grey wolf optimizer,GWO）优化支持向量回归（support vector regression,SVR）中的参数,提出并实现一种基于网络搜索数据和GWO-SVR模型的旅游短期客流量预测模型,并用参数优化后的SVR对客流量进行建模预测. 以四川省九寨沟和四姑娘山两个景区为例,构建GWO-SVR、ARIMA、BPNN、SVR、CS-SVR、PSO-SVR和无网络搜索数据等客流量预测模型进行实证分析. 结果表明,GWO-SVR模型均优于其他模型,具有更高的预测精度.     

一种软计算混合策略在多相催化剂建模与预测中的应用

为了减少发现新的碳一多相催化剂的时间、降低消耗,加速二甲醚合成工业化进程,提出一种新的软计算混合策略并应用于碳一多相催化剂建模与预测研究。支持向量回归机(Support Vector Regression,SVR)作为一种新的机器学习算法,能较好地解决小样本、高维、非线性和局部极小点等实际问题,在混合策略中被用于多相催化剂组分模型的开发。SVR模型的超参数选择采用启发式全局优化搜索算法——自适应混沌粒子群算法来提高SVR模型的预测精度和泛化能力。新策略的主要优势是在反应机理未知或难以获取的情况下,建模完全由历史进程的少量样本空间完成,避免了传统催化剂研发过程中"试错实验"的盲目性和偶然性。通过对两种不同建模方法、三种不同SVR超参数优化策略在Cu-Zn-Al-Zr合成二甲醚催化剂组分模型中的对比研究得出,新策略在多相催化剂建模与预测上是一个有前途的发展方向。     

基于支持向量机的烧结能耗及性能指标预测模型

针对烧结过程中能耗和性能指标预测方法精度不高、训练时间长的问题,首先,在总结当前预测建模方法的基础上,将回归型支持向量机(support vector machine for regression,SVR)引入烧结生产系统,分析了2种建模模式;然后,给出基于SVR预测建模一般流程;最后,以某大型钢铁企业为例进行验证,并与传统的多元线性回归、反向传播(back propagation,BP)神经网络、径向基函数(radical basis function,RBF)网络和极限学习机(extreme learning machine,ELM)等预测方法在相同模式内和不同模式间进行比较.结果表明,SVR方法可快速获得理想的预测结果,在预测精度和时间效率上具有优势.     

基于机器学习的钻孔数据隐式三维地质建模方法

针对基于钻孔数据的传统显式三维地质建模方法存在过程繁琐、模型质量难以保证等缺点,本文提出了一种基于机器学习的隐式三维地质建模方法,将地层三维建模问题转换为地下空间栅格单元的属性分类问题.分别基于支持向量机、BP神经网络等分类算法,实现了钻孔数据的自动三维地质建模.实际建模结果表明,对于有限、稀疏的钻孔数据,支持向量机方法建模准确率较高,建模效率、效果优于显式建模方法.最后通过敏感性分析研究了超参数对建模结果准确率、模型形态的影响,为可控的自动三维地质建模提供了一种新的解决思路.     

化工数据预处理及其在建模中的应用

对化工数据预处理问题进行了研究,阐述了化工数据智能建模中辅助变量选择、数据采集、数据校正、输入数据降维等各种数据预处理的思路与方法。仿真实验表明:对数据进行有效的预处理,可以改善模型的精确度。     

基于Petri网的间歇式化工生产过程建模与调度监控器设计

针对间歇式化工生产过程,提出了一种基于Petri网的调度监控器设计算法.首先给出了间歇式化工生产系统的建模方法,并得到了其Petri网模型;其次将生产工艺描述为字符串控制目标;随后,给出在对象Petri网上设计工艺控制库所的方法,使得闭环系统满足给定的字符串控制目标;最后,利用某化工厂一种树脂生产过程的建模和调度监控问题验证了本文的方法.     

KPCA-KPLS方法在pH中和过程建模中的应用

针对化工过程中的具有严重非线性、不确定性、时变性的复杂pH中和过程系统建模问题,提出一种基于核主元分析(KPCA)与核偏最小二乘(KPLS)相结合的建模方法.在高维特征空间内,该方法通过KPCA有效地提取输入数据的非线性主元,利用KPLS方法将输入变量投影在潜在变量上,再用输入与输出变量之间的协方差信息提取潜在特征建立pH中和过程模型.为验证其有效性,将KPCA-KPLS方法应用到弱酸强碱中和过程、强酸强碱中和过程实例中,并与核偏最小二乘、核主元分析_支持向量机(KPCA-SVM)、核极限学习机(KELM)、极限学习机(ELM)、最小二乘支持向量机(LSSVM)、SVM等方法进行比较.实验结果表明:KPCA-KPLS方法具有很高的动态建模精度.     

Boosting集成支持向量回归机的滑坡位移预测

支持向量回归机(SVR)在实际的学习应用中,由于数据时空的复杂性和算法本身的参数选择,学习模型难以达到预期的效果.针对这个问题,提出了基于Boosting集成的支持向量回归机方法.通过在原始数据集加权采样的基础上,进行多次迭代子SVR机器学习,不断调整样本权值再采样,优化机器学习模型,然后对迭代所得的每级支持向量回归结果按某种组合方法进行集成,得到最终的回归函数形式.应用该方法进行了仿真试验和滑坡变形时序预测研究.结果表明:使用集成的SVR进行回归预测较之单一的SVR具有更高的准确性和更好的泛化性.对Boosting与Bagging 2种不同的集成SVR,进行了比较研究,试验结果表明,2种算法性能相差不大,总体上前者强于后者.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

英文诗歌中的喻类修辞

为了有助于提高英文爱好者的个人情操、文化素养和学习兴趣,以及专业人员对英语学习和研究进行多途径的探索,本文通过一些精选诗歌的引证和分析,着重论述了喻类修辞法在英文诗歌中的运用其及效果。     

Man Is Unable to Change the Miserable Life——Analysis of the Arrangement of Four Characters in The Glass Menagerie

Tennessee Williams is considered as one of the most important American playwrights since World War II.The Glass Menagerie is his first successful drama,which describes a tragic situation of family and means to say that Man is unable to change the miserable life,no matter whatever means he try,This essay focuses on the analysis of the arrangement of the four main characters:Laura.Amanda,Jim and Tom to reveal the theme.Laura is fragile.Amanda is brave.Jim is vital.Tom is sensible.And all of them develop and try the different means to struggle against life,but fail tragically.With the evidence,the paper comes to conclusion naturally that Man is unable to change the miserable life,and he dooms to fail.     

Characterization of root-nodulating bacteria on Retama raetam in arid Tunisian soils

The aim of this study is to investigate the diversity of Retama raetam root-nodule bacteria isolated from arid regions of Tunisia. Twelve isolates, chosen as representative for different 16S rRNA gene patterns, were characterized by 16S rRNA gene sequencing and phenotypic analysis. Isolates were assigned to Sinorhizobium, Rhizobium and Agrobacterium. Symbiotic properties of Sinorhizobium and Rhizobium isolates showed a large diversity in their capacity to infect their host plant and fix atmospheric nitrogen. Strain RK 22 identified as Rhizobium was the most effective isolate.     

An Affordable Accurate Evaluation of the Binding Conformations Predicted by Molecular Docking Studies in Bio-System

正Recently,docking has been widely used to predict the binding-modes of protein-inhibitors,when the crystal complexes structure was absent.Most docking algorithms are able to generate a large number of probable conformations,it,however,is difficult to effectively evaluate these docking poses and identify the most reasonable bindingmode.In the present study,on the basis of the crystallographic data of human 3-hydroxy-3-methylglutaryl coenzyme     

WIMAX与WI-FI技术分析及联合组网

介绍了WiMAX与Wi-Fi两种无线宽带接入技术,并对两者之间的关系及相互之间的影响做了对比及分析,并对WiMAX的关键技术进行了详细说明,最后对两者的联合组网方式做了简单的探讨。