证据理论在多源数据融合故障诊断中的应用

分析了证据理论,借助证据冲突概率分配函数解决了证据冲突问题,通过基于矩阵分析的融合算法解决了证据理论在应用中存在的计算瓶颈问题,构建了基于D-S证据理论的多源数据融合故障诊断系统。算例结果表明,该方法所要的融合时间近似与数据源个数成线性关系,该诊断系统提高了诊断的可靠性和准确性,降低了诊断的不确定性。     

多传感器数据融合技术(下)

3　数据融合方法多传感器数据融合虽然未形成完整的理论体系和有效的融合算法,但是在不少应用领域根据各自的具体应用背景,已经提出了许多成熟并且有效的融合方法。3 1　Ｄ Ｓ证据推理方法Ｄ Ｓ(Ｄｅｍｐｓｔｅｒ Ｓｈａｆｅｒ)证据推理是贝叶斯推理的扩充,其3个基本要点是:基本概率赋值函数ｍｉ、信任函数Ｂｅｌｉ和似然函数Ｐｌｓｉ。Ｄ Ｓ方法的推理结构是自上而下的,分3级,推理结构如图4所示。第1级为目标合成,其作用是把来自独立传感器的观测结果合成为一个总的输出结果(ＩＤ)。第2级为推断,其作用是获得传感器的观测结果并进行推断,将…     

多参数融合的球磨机振动特征提取方法

针对单信号特征参数不能准确表征球磨机负荷状态的问题,采用时域统计分析方法和AR模型方法提取球磨机振动的时域特征参数和频域特征参数,并利用D-S证据理论用于融合振动信号的时域和频域特征参数,并计算每个特征参数的基本概率分布函数.将基本概率分布函数值作为球磨机负载状态的特征值,建立多振动特征参数的特征向量模型.结果表明,多振动特征参数的特征向量模型能很好地表征球磨机负荷状态,为球磨机负荷预测提供数据支持.      

澜沧老厂多源地学数据融合分析

以多源地学数据为基础, 将澜沧老厂矿区的遥感信息与地球物理信息进行融合处理, 并对融合的结果进行简单的相关性分析, 为地质勘查和成矿预测提供可靠的资料。     

基于多传感器融合的电机在线状态监测方法

电机系统的安全运行与生产过程的稳定性息息相关,因而对电机运行状态的在线检测和诊断具有重要意义.随着传感器和嵌入式技术的发展,电机监测方式也由以人工和单一的信号为主向多传感器检测方向发展.为进一步探究多传感器检测的准确性和有效性,基于嵌入式系统面向多种电机状态参数实时监测与分析,设计开发了一套电机在线状态监测系统,利用小...     

矿山低空航空摄影测量中多源数据融合方法研究

为了降低由于数据冲突引起的数据融合效果差的问题,提出矿山低空航空摄影测量中多源数据融合方法研究.将采集到的不同角度的数据的时间和空间进行统一,将过滤了存在较大干扰后的数据建立相关关系,在此基础上对数据进行融合处理.试验结果表明,本文方法融合结果建立的矿山地质环境图数据完整、清晰,具有较高的实际应用效果.     

矿山地质灾害应急测绘中多源数据融合技术的应用效果分析

为解决传统矿山地质灾害应急测绘相邻点之间的距离中误差高的问题,提出矿山地质灾害应急测绘中多源数据融合技术的应用效果分析.通过精准采集矿山地质灾害应急测绘数据,基于多源数据融合技术高效处理应急测绘数据,建立矿山地质灾害应急测绘数据3D绘图协议,实现矿山地质灾害应急测绘.设计实例分析,结果表明,设计测绘方法相邻点之间的距离...     

基于多分辨率分析的多传感器遥感图像融合方法

给出了一种基于非抽样Contourlet变换的遥感图像融合算法.根据分解后不同层次的特点采用不同的融合规则,对高频分量采用区域能量的融合规则,使得融合图像的光谱质量和空间质量得到均衡提高、实验表明,该算法可以更好地表现高分辨率全色图像的细节特征,同时在保持多光谱图像的光谱信息方面具有较大优势.     

浅谈多源数据融合技术及其在地质矿产勘查中的应用

本文通过开展多源数据融合技术简述,分析多源融合技术与当地地质勘查工作的结合情况,论述了多源数据融合技术具体应用方式。     

多传感器数据融合技术在烧结矿碱度预测中的应用

介绍了安钢烧结厂利用BP神经网络进行多传感器数据融合的烧结矿碱度的预报模型。通过对现场实际数据进行仿真，表明该方法鲁棒性强，准确性高，泛化能力广，具有很强的实用性和推广价值。     

活塞式空气压缩机故障的振动诊断

活塞式空气压缩机的主要功能由往复运动完成,振动是其主要故障标志之一。本文分析了空压机振动的常见故障及振动特征,提出用振动测量分析诊断空压机故障的方法,实际应用后,可有效降低设备故障率,确保设备正常运行。     

Finite-Element Analysis of Time Domain Reflectometry Cable-Grout-Soil Interaction

Three-dimensional finite element analysis is combined with field and laboratory measurement of time domain reflectometry (TDR) cable-grout response to analyze the interaction between the cable, grout, and surrounding soil mass during localized shearing. Finite element (FE) model parameters for the cable and cable-grout interface elements are back-calculated by matching results from laboratory shearing tests to FE calculated response. These parameters are employed in subsequent FE model geometries to model the behavior of TDR cable-grout composites in soft soils. Optimal grout and cable design is determined by analyzing the relationship between grout strength and stiffness and calculated cable shear stress.     

Time Domain Flutter and Buffeting Response Analysis of Bridges

A time domain approach for predicting the coupled flutter and buffeting response of long span bridges is presented. The frequency dependent unsteady aerodynamic forces are represented by the convolution integrals involving the aerodynamic impulse function and structural motions or wind fluctuations. The aerodynamic impulse functions are derived from experimentally measured flutter derivatives, aerodynamic admittance functions, and spanwise coherence of aerodynamic forces using rational function approximations. A significant feature of the approach presented here is that the frequency dependent characteristics of unsteady aerodynamic forces and the nonlinearities of both aerodynamic and structural origins can be modeled in the response analysis. The flutter and buffeting response of a long span suspension bridge is analyzed using the proposed time domain approach. The results show good agreement with those from the frequency domain analysis. The example used to demonstrate the proposed scheme focuses on the treatment of frequency dependent self-excited and buffeting force effects. Application to nonlinear effects will be addressed in a future publication.     

Time Domain Analysis on the Dynamic Response of a Flexible Floating Structure to Waves

A time-domain numerical method is developed to analyze the hydroelastic responses of flexible floating structures to waves; in which, the boundary element method is applied to evaluate the fluid motion and the finite-element method to analyze the elastic deformation of structure. The dynamic wave-structure interaction is simulated by prescribing the conditions on a wave generation boundary for each time step and by satisfying the continuity of the pressure and displacement on the fluid-structure interface. A time-domain solution is obtained in a predictor-corrector scheme and through a time-stepping computation. The effect of space and time discretizations on the convergence and stability of solution for regular, random and solitary waves is discussed by comparing among numerical solutions. The validity of the present method is verified by comparing it with the experimental results for the three kinds of waves mentioned. Further, the fission of a solitary wave under a flexible floating structure is observed both in numerical analysis and experiments.     

Time Domain Identification of Frames under Earthquake Loadings

The purpose of this paper is to examine the adaptive identification method and the nonlinear system identification technique through numerical simulation on seismic response of building structures. For the identification of a time-variant system and a system with an abrupt change of modal parameters, two parameter adaptation algorithms in recursive identification methods are discussed: recursive least square algorithm with constant trace and adaptive fading Kalman filter method. Based on the equivalent linear model, the time-variant model parameters can be identified. The tracking ability on the identification of a time-variant system is discussed. For the identification of the nonlinear system, the forward including algorithm and the neural network training algorithm were used to estimate the modal parameter of the nonlinear autoregressive moving average model, and the accuracy on the predicted output of nonlinear model identification was discussed.     

Extension of Weighted Integral Stochastic Finite Element Method to the Analysis of Semi-Infinite Domain

In this study, one of the nonstatistical stochastic methods, i.e., the weighted integral method, is extended to analyze the semi-infinite domain. In the semi-infinite domain the region of uncertainties is vast when compared with that of the ordinary finite domain. Accordingly, the response variability in this domain has more significance than that in the ordinary finite domain. In modeling the semi-infinite domain, the coupled use of the infinite element is adopted. The results obtained using the proposed weighted integral method is compared with those obtained by Monte Carlo simulation. It is shown that the results of proposed method and those by the Monte Carlo simulation are in good agreement with each other showing the adequacy of the proposed method. In addition, the improvement in the response statistics, when the infinite domain is included in the model, is also attained, which shows the importance of the inclusion of far field in the analysis.     

基于动态核聚类分析的煤气鼓风机故障诊断方法分析

对煤气鼓风机组常见故障及其振动特性进行了分析,运用核函数技术,对矩阵运算和变换的结果进行动态聚类分析,结合模糊诊断方法建立了基于动态核聚类分析的自动诊断系统模型,为提高风机振动监测和故障诊断的准确性提供保证.     

Impulse Response of Elastic Half-Space in the Wave Number–Time Domain

This paper presents formulas for the response functions in the mixed wave number–time domain for a homogeneous, elastic half-space subjected to impulsive, spatially harmonic sources on its surface. These functions are useful when obtaining the wave field in a half space elicited by dynamic surface sources of arbitrary spatial distribution on the surface, in either two or three dimensions. The formulas in this paper are obtained by contour integration of the Green’s functions in the frequency–wave number domain. The correctness and accuracy of these solutions is then assessed by comparison with the results of the well-known transient response functions for suddenly applied loads in both two and three dimensions.     

Decomposition of Niobium Ore by Sodium Hydroxide Fusion Method

The decomposition kinetics of niobium ore in the NaOH system was studied experimentally. The results show that the reaction products are sodium metaniobate and sodium niobate formed by the reaction of pyrochlore with sodium hydroxide under roasting. The effects of temperature, particle size, and mass ratio of alkali-to-ore were studied. The conversion rate of niobium exceeded 99 pct after 20 minutes at 923 K (650 °C) with a mass ratio of alkali-to-ore 1.2:1 and with initial particle size 75 to 106 μm. The kinetic study indicates that the shrinking core model is applicable and the process is controlled by a chemical reaction. The activation energy was calculated to be 78.82 kJ mol^–1.     

时间序列分析

论述了时间序列分析技术的作用。利用时间序列分析预测未来事物的发展。