基于环形拓扑自适应差分进化算法优化神经网络的压气机流量特性预测

为提升轮机模拟器中柴油机非额定工况下的仿真精度,提出一种基于有限数据的混合方法来预测多工况下的压气机流量特性.该方法采用一种基于环形拓扑差分进化算法来优化三层前馈神经网络参数,利用有限的给定工况下的流量特性数据,预测压气机流量特性曲线.采用神经网络来拟合压气机流量特性的非线性映射关系,利用差分进化算法优化调整神经网络的连接权重、连接偏置、连接开关等难以调整的重要参数.仿真结果表明,基于有限数据的方法可较好地拟合船舶压气机流量特性,采用环形拓扑的自适应差分进化算法优化调整神经网络的重要参数具有一定的有效性.本文提出的混合方法具有更好的泛化能力和搜索精度,可作为处理类似预测问题的有效手段.     

宽带无线接入网的成比例带宽分配

为了改进亏空公平优先队列算法,提出一种成比例带宽分配算法.基站将服务连接的带宽请求按照优先级排队,根据服务质量参数先分配部分带宽,超出的请求基于子站总请求带宽的大小成比例分配给服务连接.仿真采用2维离散时间Markov调制Poisson过程的模型产生实时轮询服务和非实时轮询服务连接的数据源.与亏空公平优先队列算法相比,该算法不仅满足各类服务连接的服务质量要求,而且改善子站总的吞吐量和流量突发增加的问题.该算法还提高了子站间及不同优先级服务连接间的公平性.     

基于分形布朗运动的等效带宽及其参数计算算法

在推导一种新型的基于分形布朗运动(fractional brownian motion,FBM)的等效带宽计算模型的基础上,提出了基于小波分析的Hum参数计算模型.首先给出了ON/OFF数据源的数学定义,然后在此基础上推导了基于FBM的等效带宽计算模型.时模型的敏感性分析表明,Hurst参数是该模型的重要参数,文中提出了一种改进的基于小波分析的Hurst参数检测算法.仿真证明,所提的等效带宽模型正确有效,Hurst参数检测算法精度显著提高.     

基于非线性虚拟材料栓接结合部动力学建模方法

为仿真栓接结合部非线性动力学特性，提出一种基于非线性横观各向同性虚拟材料的栓接结合部动力学建模方法.基于有限单元法，利用8节点实体单元构建被连接件及用来等效栓接结合部的横观各向同性虚拟材料层，虚拟材料层与被连接件固接.采用非线性虚拟材料等效栓接结合部，以模拟含栓接结合部结构在不同幅值的外简谐激振下所体现出的非线性刚度特性.为提高非线性模型计算精度，将非线性横观各向同性虚拟材料层进行分区处理，每个区域虚拟材料参数分别由该区域虚拟材料的形变确定.最后，对模型进行局部降维，在时域下求解模型的幅频响应，通过对比仿真计算结果和试验结果，验证所提出建模方法的可行性与有效性.     

海水淡化轴向柱塞泵的虚拟样机技术研究

为了研制反渗透海水淡化用高压轴向柱塞泵,采用虚拟样机技术对其机械动力学和压力流量特性进行了预测.泵的三维几何模型基于结构设计得到：通过施加运动学约束和对关键零件进行进行柔性化处理建立了泵的机械模型;通过对泵内动态压力和流量分析得到了泵的流体模型;联合机械模型与流体模型建立了泵的虚拟样机模型.通过运行泵虚拟样机模型获得了主要零件的运动学和动力学规律、泵出口的动态流量和压力规律及关键零件的动态等效应力等数据,仿真结果表明：泵的主要性能达到了设计要求,关键零件具有较大的强度裕度,可以在更高的压力等级下运行.     

基于LTCC的Ka波段无源等效腔体分析与优化设计

为了能够在Ka波段采用低温共烧陶瓷(LTCC)技术实现收发组件小型化设计,提出了LTCC无源等效腔体模型.将有源芯片置入LTCC腔体中,解决了电磁场干扰问题.但腔体效应会引起串扰和振荡,造成放大器工作的不稳定.为此提出腔体谐振频率远离工作频率的设计方法,在无源等效腔体设计过程中采用两种不同馈电结构,利用基于神经网络模型的遗传算法和三维电磁场仿真软件对无源等效腔体参数进行优化设计,得到了近似一致的设计结果,满足放大器稳定的最优无源等效腔体参数为4.5 mm×3.5 mm.     

基于交叉口多相位信号控制的路网容量

构建了一种用于描述交叉口多相位信号控制路网容量的双层规划模型.其中,下层模型是一个交叉口多相位信号控制路网用户均衡分配模型,用以求解给定信号配时参数和交通需求量下的路段均衡流量,该模型考虑了各相位下的信号延误.上层模型是一个非线性规划模型,模型以路网容量最大为目标,对信号配时参数和O-D需求量进行优化.双层规划模型采用基于灵敏度分析的BLABD算法求解,算法的主要思想是通过差商的方法估计路段均衡流量对设计变量的导数,从而将上层模型中未知路段流量函数展开为一个线性函数.算例分析结果显示,该算法能有效求解多相位信号控制路网容量问题,具有实用价值.     

基于FRA的变压器绕组变形的分频段研究

变压器绕组在较高频率的电压作用下,每个绕组本身均可视为一个由线性电阻、电容、电感等分布参数构成的无源线性双口网络,通过对该双口网络的研究可以得到变压器绕组在各个频段的等效模型.频率响应分析(frequency response analysis,FRA)是变压器绕组分频段研究的主要方法.介绍了FRA的原理,分析绕组参数变化对不同频段频响曲线的影响,给出了变压器绕组在不同频段的具体等效模型.     

考虑局域接触特征的栓接结合部动力学建模表征与参数辨识

目前关于栓接结合部动力学特性的非线性建模研究忽略了栓接处有效接触区域的影响，所建立的等效模型与结合部实际装配特征存在较明显的偏差.对此，提出一种考虑局域接触特征的栓接结合部动力学建模方法.引入柱状正交非线性虚拟材料模型表征结合面在外载荷作用下表现出的柔性结合特征；通过建立虚拟材料微单元应力应变分析模型，基于最小势能原理和吉村允孝法，理论推导虚拟材料的物理参数计算方程；基于深度神经网络（Deep Neural Network， DNN）建立栓接结合部接触区域的几何参数预测模型，实现栓接结合部不同接触状态与接触特性区域直径的非线性映射，最终建立具有结合部实际装配特征的栓接结合部动力学模型.以自由边界状态下的螺栓组连接钢板试件为实验测试对象，采用上述方法建立有限元仿真模型，将模态仿真与实验测试的结果进行对比，验证了模型的有效性和准确性.与未考虑局域接触特征的虚拟材料建模方法对比表明，该方法建立的模型在均方根误差（Root Mean Square Error， RMSE）综合评价指标上有明显提升.     

虚拟角色动作编辑及运动控制

为了直接利用虚拟角色表面模型进行动作编辑及运动控制,提出了一种通用的虚拟角色骨骼建模及运动控制方法.该方法通过对分块的虚拟角色表面模型进行边缘判定、关节点计算、最顶块确定,然后按层次连接各关节点生成虚拟角色骨骼模型.在此基础上根据虚拟角色行走运动模型和运动约束关系,研究了基于参数关键帧技术的运动过程动画制作、不同运动间自动插补动画的动作平滑过渡技术以及利用动作幅度权值对动作姿态的调整技术.最后,采用实时控制和路径点控制2种方式进行了虚拟角色在虚拟场景中的运动控制,取得了较好的实现效果.     

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.     

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.     

A computer generator for randomly layered structures

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

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     

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.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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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。     

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.     

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