管桁架-索网混合钢结构的计算分析

为更好地对管桁架-索网混合钢结构进行找形,在SAP 2000和3D3S中应用两种不同的初始态找形方法以比较对计算结果的影响.在SAP 2000中采用非线性有限元分析方法找形,在3D3S中采用力密度法和有限元法进行混合找形,并进行初始态、动力以及载荷态分析.比较分析这两种找形方法的计算结果,发现二者的计算结果误差不大,均为可行的简化计算方法.     

基于混合模型的网络流量预测算法

研究网络流量准确预测,针对网络优化控制问题,由于网络数据拥塞严重,网络流量变化具有高度自相似性、非线性和多尺度等特点,线性数据的传统预测方法无法准确刻画网络流量的非线性变化规律,导致预测准确率低.为了提高网络流量的预测准确率,在分析网络流量变化特征的基础上,提出一种小波分析的网络流量混合预测模型.混合模型首先利用小波分析将网络流量分解线性和非线性部分,然后分别采用ARIMA模型和BP神经网络模型对其进行预测,最后采用小波分析对线性和非线性部分预测结果进行重构,得到混合模型最终预测结果.仿真结果表明,混合模型比其它网络流量预测模型具有更高的预测准确率,为网络优化控制提供了有效分析方法.     

一种基于多重涡流新型微混合器的设计与实验

设计了一种基于多重涡流的新型微混合器结构.该结构中多个呈反向分布的规则排列的扩张和收缩结构可产生迪恩流与扩张涡流,基于此,可进行高效率的被动式混合.首先阐述了该结构产生内部迪恩流和扩张涡流的机理,并利用COMSOL软件对该结构进行了液流混合过程的三维数值模拟验证,分析了不同流体流速对多重涡流强弱和混合程度的影响.最后制作了该微混合器,利用2种不同的染料进行了混合实验,通过分析样品的混合效果验证了该混合器的性能.仿真和实验结果均表明:该混合器在低输入流速(0.01 μL/s)和高输入流速(7μL/s)下均可实现高效快速的混合,在0.8cm的距离内即可实现完全混合,在输入流速为5 μL/s时最高混合效率可达98.6％.     

基于列车悬挂系统的半主动混合控制仿真分析*

为了改善列车高速运行时的乘坐舒适性,采用车辆二自由度模型对开关型和连续型两种控制策略进行对比分析,根据传递特性分析结果提出了混合控制策略,同时研究了调整系数对混合控制策略的影响.为进一步验证控制策略的有效性,建立了UM与Simulink联合仿真整车模型,对二系横向减振器施加此控制策略,并进行了仿真分析.结果表明:在调整系数选取适当的情况下,该控制策略可同时兼顾开关型和连续型两种控制策略的优点,降低了车体横向加速度,改善了列车的横向平稳性.     

电动汽车混合储能系统拓扑结构与控制策略综述

混合储能系统兼具高功率密度和高能量密度,可有效提升电动汽车动力性能和续驶里程.围绕电动汽车混合储能系统拓扑结构和控制策略,本文首先对混合储能系统及其典型储能装置进行概述,并对混合储能系统技术难点进行分析.之后在分析隔离型双向DC/DC变换器和非隔离型双向DC/DC变换器拓扑结构、工作原理和基本特性的基础上,综述分析了被动、半主动和全主动3种混合储能系统的工作原理和优缺点.然后,重点分析了基于规则的控制策略、基于优化的控制策略和混合控制策略3大类混合储能系统控制策略的工作原理.最后对混合储能系统的发展趋势进行了展望.     

基于混合高斯模型的窄带目标跟踪方法

基于混合高斯模型的轨迹分布融合方法适用于窄带目标跟踪系统.这种算法针对宽带跟踪结果的不精确,目标模糊,窄带跟踪需要依赖人工实现的问题,提出了一种基于混合高斯模型的自动窄带目标跟踪技术.该方法首先将目标方位分布看做是混合高斯模型,利用期望最大化算法估计混合高斯模型中的参数,然后利用混合高斯模型对目标方位进行聚类,最后利用平均加权法对目标方位进行融合,得到清晰稳定的目标跟踪结果.     

混合模型在经济时间序列预测中的应用研究

研究经济预测问题,为社会经济发展提供预测依据.由于经济时间序列是一种多维、非线性数据,采用单-的线性或非线性模型都不全面反映特点,导致预测精度不理想.为了提高经济时间序列预测精度,提出一种多变量自回归(CAR)和支持向量机(SVM)相结合的混合预测方法.混合方法首先利用CAR模型对经济时间序列的线性部分进行预测,然后采用支持向量机对非线性部分进行预测,将预测结果组合在-起,得到混合模型的预测结果.实验结果表明,混合模型的预测精度明显优于单独模型;发挥了2种模型的优势,得到一种精度高的经济预测效果.     

数模混合对消系统比例积分控制策略研究

对基于积分控制的数模混合对消系统进行了建模与理论分析,研究了其稳定性、暂态特性和稳态特性,为了兼顾系统的收敛速度和稳态误差,提出了一种先比例后积分的控制策略,搭建了数模混合对消系统的硬件平台,实验结果验证了策略的可行性和有效件.     

燃料电池混合动力车能源配置方法研究

燃料电池混合动力车能源系统的配置包括元件尺寸选型、控制策略确定和车辆行驶循环工况选择三要素.文中针对某燃料电池混合动力车的能源系统配置,对能源系统选型、控制策略类型和车辆行驶循环工况三要素分别进行了系统论述.借助于Advisor车辆仿真平台,通过对控制策略采用基线控制的燃料电池混合动力车能源系统配置的实例分析,提出燃料电池混合动力车给出其能源配置的一般方法,最后对仿真结果进行了分析并验证配置方法的有效性和可行性.     

混合高斯模型和机器视频的火灾检测的实现

针对目前基于传感器技术的火灾探测器存在检测区域小、干扰大、误报率高等不足,提出了一种基于混合高斯模型与机器视觉相结合的火灾检测方法.该方法通过对摄像头获取的图像信息进行处理和分析,利用火灾早期产生的烟雾和火焰的颜色及形体变化特征来探测火灾.通过建立混合高斯模型对火灾进行识别,再对识别结果进行进一步的动态特征识别.试验证明,该方法克服了传感器检测方法的缺点,实时性好、识别率高.     

混合进制及其在贝叶斯网络结构学习中的应用

贝叶斯网络因其处理不确定性问题的能力及其良好的因果推理机制已成为因果数据采掘的主要技术,同样,它也是实现分布估计算法的一个重要途径.而应用贝叶斯网络所解决的一些实际问题的知识表示中会用到混合进制数.因此,给出了十进制数与混合进制数之间的相互转化定理及其严密的理论证明,旨在应用定理中简单的公式来代替以往复杂的转化算法.     

Combination of LIGA with other microstructure technologies

The combination of the LIGA technique with other microstructure technologies like silicon technology, membrane technologies, and mechanical micromachining gives access to the development and manufacturing of new microsystems. The quasi-monolithic integration of LIGA microstructures on top of a CMOS-Wafer using a molding process will be shown which has the potential to integrate a LIGA component directly with microelectronic circuits. By combining mechanical micromachining, plastic molding, and membrane technologies a micropump has been developed which is one of the key components of the fluid handling module of microanalysis systems together with the well known LIGA microspectrometer. In the case of the microspectrometer, a small-scale series production was installed.     

Combination of LIGA with other microstructure technologies

 The combination of the LIGA technique with other microstructure technologies like silicon technology, membrane technologies, and mechanical micromachining gives access to the development and manufacturing of new microsystems. The quasi-monolithic integration of LIGA microstructures on top of a CMOS-Wafer using a molding process will be shown which has the potential to integrate a LIGA component directly with microelectronic circuits. By combining mechanical micromachining, plastic molding, and membrane technologies a micropump has been developed which is one of the key components of the fluid handling module of microanalysis systems together with the well known LIGA microspectrometer. In the case of the micro-spectrometer, a small-scale series production was installed. Received: 30 October / Accepted: 1 December 1995     

A parallel mixed time integration algorithm for nonlinear dynamic analysis

This paper presents a parallel mixed time integration algorithm formulated by synthesising the implicit and explicit time integration techniques. The proposed algorithm is an extension of the mixed time integration algorithms [Comput. Meth. Appl. Mech. Engng 17/18 (1979) 259; Int. J. Numer. Meth. Engng 12 (1978) 1575] being successfully employed for solving media-structure interaction problems. The parallel algorithm for nonlinear dynamic response of structures employing mixed time integration technique has been devised within the broad framework of domain decomposition. Concurrency is introduced into this algorithm, by integrating interface nodes with explicit time integration technique and later solving the local submeshes with implicit algorithm. A flexible parallel data structure has been devised to implement the parallel mixed time integration algorithm. Parallel finite element code has been developed using portable Message Passing Interface software development environment. Numerical studies have been conducted on PARAM-10000 (Indian parallel supercomputer) to test the accuracy and also the performance of the proposed algorithm. Numerical studies indicate that the proposed algorithm is highly adaptive for parallel processing.     

Rotation and intensity invariant shoeprint matching using Gabor transform with application to forensic science

Shoe marks at the place of crime provide valuable forensic evidence. This paper presents a technique for rotation and intensity invariant automatic shoeprint matching. Multiresolution features of a shoeprint have been extracted using Gabor transform. Rotation of the shoeprint image has been estimated using Radon transform and is compensated by rotating the features in opposite direction. The performance of the proposed algorithm has been compared with the technique in which the features have been determined using Fourier transform and its power spectral density. Shoeprint database has been generated by inviting participants to tread on an inkpad and then stamp on a piece of paper. Euclidian distance classifier has been used to find a suitable match. The performance of the proposed algorithm has been evaluated in terms of correct recognition rate computed using best match score at rank ‘1’ and cumulative match score for the first four matches with rotation, intensity and/or mixed attacks. A good matching performance has been achieved with rotation attack; typically 91 percent at rank ‘1’ and 100 percent at rank ‘2’ for full prints. Performance of the proposed technique is better even for partial shoeprints. Experimentation has also been carried out by perturbing shoeprint images with Gaussian white noise, salt and pepper noise to evaluate the robustness of the proposed technique.     

A finite-difference scheme for mixed boundary value problems of arbitrary-shaped elastic bodies

This paper presents a program based on a finite-difference technique, which solves plane stress and plane strain problems of arbitrary shaped elastic bodies with mixed boundary conditions. A new formulation of governing equations in terms of the displacement potential function ψ, as introduced by Uddin (Finite difference solution of two-dimensional elastic problems with mixed boundary conditions, MSc Thesis, Carleton University, Canada, 1966), has been used. This formulation has the capability to handle problems of mixed boundary condition, which is beyond the ability of the conventional formulations in terms of Airy's stress function φ. Results found with this program for classical problems are in very good agreement with known solutions. This program can handle practical boundary conditions very efficiently.     

基于C++ Builder与LabWindows/CVI平台的数据采集处理系统的研究与应用

本文介绍了一种基于Borland C Builder与LabWin-dows/CVI平台的数据采集与处理系统.该系统应用于对滚动轴承的故障信号进行数据采集与分析处理。用BorlandC Builder语言编写数据采集程序,将采集到的数据传给LabWindows/CVI,用LabWindows/CVI编写数据处理程序。数据传送时用到了动态连接库技术(DLL)。通过实例证明了这两种语言结合使用的优势。     

Scalable algorithms for clustering large datasets with mixed type attributes

Clustering is a widely used technique in data mining applications for discovering patterns in underlying data. Most traditional clustering algorithms are limited to handling datasets that contain either numeric or categorical attributes. However, datasets with mixed types of attributes are common in real life data mining applications. In this article, we present two algorithms that extend the Squeezer algorithm to domains with mixed numeric and categorical attributes. The performance of the two algorithms has been studied on real and artificially generated datasets. Comparisons with other clustering algorithms illustrate the superiority of our approaches. © 2005 Wiley Periodicals, Inc. Int J Int Syst 20: 1077–1089, 2005.     

COMBINED QUALITATIVE/QUANTITATIVE SIMULATION MODELS OF CONTINUOUS-TIME PROCESSES USING FUZZY INDUCTIVE REASONING TECHNIQUES

Abstract

A new mixed quantitative and qualitative simulation methodology based on fuzzy inductive reasoning is presented. The feasibility of this methodology is demonstrated by means of a simple hydraulic control system. The mechanical and electrical parts of the control system are modeled using differential equations, whereas the hydraulic part is modeled using fuzzy inductive reasoning. The technique is described in detail in the first part of this paper. The example is shown in the second part of the paper. The mixed quantitative and qualitative model is simulated in ACSL, and the simulation results are compared with those obtained from a fully quantitative model. The example was chosen as a simple to describe, yet numerically demanding process whose sole purpose is to prove the concept. Several practical applications of this mixed modeling technique are mentioned in the paper. but their realization has not yet been completed     

Experimental study and thermodynamic modeling of the Cu–Sn–Si–O system and sub-systems

Phase equilibria between slag, Cu–Sn alloy and solid oxide phases, SnO₂ (cassiterite) or SiO₂ (tridymite, cristobalite) are important for oxidizing fire refining of black copper produced during the recycling of copper scrap and waste electrical and electronic equipment. Integrated experimental and thermodynamic modeling study is presented for the Cu–Sn–Si–O chemical system and its sub-systems. Experimental technique involved high-temperature equilibration, followed by rapid quenching and direct measurement of Cu, Sn and Si concentrations in the liquid and solid phases using the electron probe X-ray microanalysis. Experimental results and literature data have been used to develop the thermodynamic database for the system. The database works within the environment of FactSage software, as well as ChemApp, ChemSheet and SimuSage. Combined with other assessments, it can be used to optimize and develop recycling processes using the black copper route.