基于危险点分布比率-SVM分类的轨道不平顺峰值安全域估计

基于数据分类的思想,通过获取仿真数据进行高速铁路轨道不平顺峰值安全域估计,得到不同速度下的不平顺峰值安全域边界.首先,利用Simpack软件建立高速客车车辆动力学仿真模型,以2种不同水平轨道谱的不平顺作为激励,获取高低和轨向不平顺幅值数据以及脱轨系数、轮重减载率和轮轨横向力等安全性指标数据,并依据一定的安全性评判准则将幅值数据标记为“安全”或“危险”2类;其次,鉴于直接利用SVM进行不平顺幅值数据分类困难的情况,提出一种基于危险点分布比率和SVM相结合的分类方法,极大地降低了分类难度,提高了分类效率,获得了最佳分类面;最后,将试验结果与国内外轨道不平顺峰值管理标准进行比较.结果≯ 月:本文提出方法有效,可为高速铁路轨道平顺状态的管理及标准制定提供参考.     

在线检测系统中对预行程误差预测和补偿的应用分析

预测和补偿预行程误差,能在很大程度上提高在线检测系统中测量的精确度,基于这一原理,提出基于BP与正则化RBF神经网络的一种新的检测误差预测的方法,同时基于BP和正则化RBF神经网络,建立了一个能够在线检测系统并且预行程误差的模型,利用相关的实验数据,将已经训练好的网络运用到实际中,对加工零件的误差进行预测与补偿.     

径向基函数神经网络逼近空调管路温漂趋势的研究

针对空调管路的应变测试数据会随环境温度而产生漂移的现象,根据应变电测法,提出了基于径向基函数(RBF)神经网络拟合逼近管路真实应变值的方法,即结合正则化正交最小二乘法,逼近现实中由温度引起的漂移,间接求出空调管路较为真实的交变应变值.实验结果表明该方法是可靠的.     

基于多项式拟合的高速铁路高低轨道不平顺功率谱分析

根据某高速铁路轨道的高低轨道不平顺实测数据,基于改进的welch周期图法计算原始高低轨道不平顺功率谱密度,从波长角度提出了功率谱密度的7阶多项式拟合谱模型.通过谱密度反演算法对高低轨道不平顺序列进行数值模拟.提出了基于上、下界限谱的轨道质量评判标准.实验结果表明,提出的拟合谱模型比高速铁路无砟轨道幂函数分段拟合模型更适合于该线路的谱分析.通过本文拟合谱与时速200 km/h等级提速线路拟合谱的比较,表明该线路在波长3.3～5 m波长范围内有不平顺的趋势.为轨道不平顺的评判和线路维修提供了建议.     

基于乘数交替方向法的系统图像退化恢复方法

针对一般正则化方法不能有效解决非线性成像和高动态成像的系统退化恢复问题,提出一种非线性图像恢复方法,该方法利用乘数交替方向法解决双边全变差(bilateral total variation,BTV)模型的正则化项不平滑问题.建立包含复原图像的非线性最小二乘数据拟合项和BTV正则化项的目标函数;对目标函数进行优化;构建一套有效的乘数交替方向法(multiplier alternating direction method,MADM)求解提出的模型.利用峰值信噪比(peak signalto noise ratio,PSNR)和结构相似性度量(structural similarity index measurement,SSIM)评估图像恢复结果.对于非线性成像系统退化,提出的方法在PSNR和SSIM方面比基于TV(total variation)模型的方法分别提高4.5％和4.1％.对于高动态的成像退化问题,提出的方法获得的恢复图像PSNR值可达61.89 dB,相比其他方法,至少提高了2.9％.此外,该方法的运行时间也至少节省了26％,具有较高的计算效率.     

基于本征模函数的轨道质量评价方法

为了更合理有效地评价轨道质量,将轨道不平顺波长因素纳入轨道质量评价中,提出基于本征模函数(intrinsic mode function,IMF)的轨道质量评价方法——轨道质量能量指标(track quality energy index,TQEI).通过对轨道不平顺数据进行经验模态分解得到对应波长频段的不平顺IMF,利用频谱分析的方法求得各个IMF的能量;将各个IMF的能量与总能量的比值作为特征向量,并进行量纲一化处理,从而得到轨道不平顺IMF的能量系数;利用能量系数求得TQEI通过理论推导证明了轨道质量数(track quality index,TQI)是在不考虑波长因素作用下轨道质量能量指标的特殊形式.最后,以京广提速干线轨道不平顺数据为例,对比分析了实际检测数据TQEI与TQI的关系.结果表明:轨道质量能量指标是对TQI的细化和延续,其既起到了TQI的幅值管理作用,又可以弥补TQI在波长及幅值管理方面的缺陷,可以准确有效地对轨道质量进行评价.     

基于激光跟踪仪的轨道静态平顺性检测系统

研究了基于激光跟踪仪的轨道静态平顺性检测方法,集成激光跟踪仪、轨检小车(位移传感器和倾角传感器)、靶球及靶球支座等硬件设备,开发了轨道静态平顺性检测系统软件,建立了基于激光跟踪仪的轨道静态平顺性检测系统(TDS).在上海地铁13号线某区间,利用TDS进行了轨道静态平顺性检测试验,并采用SGJ-T-CEC-Ⅰ型客运专线轨道几何状态测量仪进行了对比测量.TDS测量系统轨道检测数据结果与SGJ-T-CEC-Ⅰ型客运专线轨道几何状态测量仪测量结果基本一致,验证了TDS测量系统可行性.     

重载铁路焊接接头不平顺对轮轨动态作用影响

为研究焊接接头不平顺演变对车辆-轨道动态相互作用的影响,现场跟踪测试得到不同服役时期的焊接接头不平顺数据,并利用车辆-轨道垂向耦合动力学模型,从时域和频域两个角度,分析计算了不同服役时期焊接接头不平顺对车轮、钢轨振动加速度及轮轨垂向力的影响.分析结果表明:焊接接头不平顺演变分为马鞍形凹陷形成阶段及焊缝区域内磨损加速阶段;焊接接头不平顺几何形态的演变对时域内轮轨动态响应结果影响显著,随着焊接接头不平顺几何形态演变,轮轨动态响应结果呈先增大后减小再增大的趋势;焊接接头不平顺几何形态演变对轮轨动态响应的频域分布影响较小,轮轨动态响应功率谱密度图中存在明显两个频段,分别为低频段31~35 Hz及高频段530~610 Hz,高频段具体位置和焊缝区域内不平顺几何形态联系紧密.     

铁路轨道高低不平顺的预测方法

轨道变形是有碴轨道结构无法避免的 .通过轨道不平顺的描述 ,预测轨道不平顺的变化规律是近代轨道力学的基本课题 ,也是制定养护维修计划的关键 .据此在介绍轨道不平顺的分类和分析国外有关轨道高低不平顺预测模型的基础上 ,提出一个利用特性矩阵描述轨道变形并进行预测的方法 .这一方法利用动态实测数据 ,全面反映不平顺的影响因素 ,适合于不同的线路条件     

基于NARX神经网络的轨道垂向不平顺估计

轨道不平顺是影响车辆平稳性和安全性的关键因素,因此及时掌握轨道不平顺的状态对保障列车运营具有重要意义。针对单个惯性量较难达到对不同波段不平顺的检测,提出一种采用非线性自回归神经网络(Nonlinear Auto-Regressive with exogenous Input Neural Networks,NARX)的轨道不平顺估计方法。以实测高铁轨道不平顺数据作为输入,通过车辆—轨道垂向耦合动力学模型仿真得到多个惯性量数据,再将归一化的多个惯性量仿真数据作为神经网络的输入,轨道不平顺作为输出,并用均方根误差和相关系数进行网络性能评价。仿真结果表明,NARX神经网络模型估计结果的均方根误差为0.028 9,相关系数为0.939 5,优于反向传播(BP)神经网络模型的均方根误差0.086 8和相关系数0.641 8,NARX神经网络拟合效果更好,表明本文所提方法能精确有效地实现轨道垂向不平顺估计。     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.