多传感器数据融合技术在故障诊断中的应用

利用多传感器数据融合的方法进行故障诊断,建立融合故障诊断系统.将故障诊断系统按数据融合的方法分为数据级融合模块、特征级融合模块和决策级融合模块.数据级融合模块主要对多传感器的测量信号进行处理,提取出故障诊断的特征信息.特征级融合模块采用3个结构相同的并行神经网络,一是进行局部诊断;二是获得决策级D-S证据理论的基本概率赋值.决策级采用D-S证据理论的方法对特征级局部诊断的结果加以融合,得到最终的诊断结果.利用此系统在汽轮机转子试验台架上进行了故障诊断,得到了令人满意的结果.     

系统级故障诊断综述

该文对现有的系统级故障诊断算法按模型、诊断方式、诊断目标分别进行了分类,进而阐述了系统级故障诊断算法的近期主要研究成果,最后预测了该领域的未来研究方向与发展前景。     

系统级故障诊断方法研究

本文全面研究了系统级故障诊断中的集中式诊断方法，概率诊断方法和分布式诊断方法，并归纳了系统级故障诊断方法的性能评价指标。     

系统级故障诊断中可诊断性的研究与发展

系统级故障诊断是保障多处理器计算机系统运行可靠性的重要手段,也是进行路由计算、容错分析的理论基础。系统级故障诊断中的可诊断性研究是为了进一步提高系统的诊断能力而进行的一系列诊断策略研究。系统级故障诊断中的可诊断性研究经历了半个世纪之后,已经发展成一个具有多种不同针对性的可诊断性理论集合,但是各个可诊断性之间的关联关系、优缺点以及适用性尚不清晰。基于此,本文在充分分析系统级故障诊断中可诊断性的国内外研究现状的基础上,明确了各个可诊断性的继承性关联关系、诊断能力以及故障的限制性条件,进而指出了可诊断性未来的发展方向。本文的研究为后续开展系统级故障诊断的可诊断性研究提供了宝贵的理论基础,具有重要的理论价值和现实意义。     

基于移动代理的主动网络系统级故障诊断模型

主动网络的可靠性和可用性是计算机网络领域的重要研究课题之一。通过分析系统级故障诊断的分布式算法设计思想,将系统级故障诊断的理论应用于基于移动代理的主动网络管理,给出了基于移动代理的主动网络的系统级故障诊断三值模型,提高了测试的可靠性和正确性。文中还阐述了分布式故障诊断算法,并利用移动代理的管理策略,达到了分布式的网络管理,具有实际应用的重要意义。     

一种面向网格结构的系统级故障诊断集团算法

网格是一种高性能分布式计算环境，它是构筑在Inernet之上的一种新型的信息技术基础设施。为保证网格可靠高效地运行，利用系统级故障诊断的方法研究网格的可靠性是很有意义的。文章提出了网格结构中的系统级故障诊断方法，并给出了一种面向网格结构的系统级故障诊断集团算法。     

多智能传感器技术在机车轴承故障诊断中的应用分析

分析了传统故障诊断方法中存在的不确定性,利用多智能传感器技术进行机车轴承故障诊断,建立融合诊断系统.该系统采用决策级融合方法来处理由于单个参数带来的诊断的不确定性.     

基于模糊神经网络的平显设备故障诊断研究*

针对平视显示器（HUD）设备自检测和地面故障诊断设备的不足,提出了一种基于模糊BP神经网络的HUD故障诊断方法。简化了故障诊断系统的结构,实现了自动性能检测和故障诊断,能够有效地辨识故障源,隔离了从LRU 级到SRU级的故障,并给出了典型测试项的故障诊断实例。作为一种先进有效的故障诊断技术已经应用于某型飞机HUD和相关系统的故障诊断。     

基于集成信息融合的智能故障诊断系统设计

提出了基于集成信息融合技术的实时智能故障诊断系统结构.在对传统BP神经网络分析的基础上引入了聚类分析方法与遗传优化算法,有效降低了BP神经网络的训练难度并提高其训练精度.将遗传神经网络与自适应神经-模糊推理系统相集成用于特征级信息融合,既提高了诊断可靠性又充分利用了诊断知识;引入D-S证据理论进行决策级融合,有效地利用了各诊断单元的诊断结果.仿真测试结果表明,该故障诊断系统能迅速、准确、可靠的诊断出各种故障.     

主运煤流线协同控制系统的故障诊断设计

针对主运煤流线协同控制系统存在维护困难的问题,开发了一种主运煤流线协同控制系统故障诊断模块,从设备级诊断、系统级诊断、远程诊断3个方面介绍了系统故障诊断原理:设备级诊断记录相关传感器、本安电源等重要事件并传输给协同控制器;系统级诊断对系统各设备统一授时,由协同控制器运行故障诊断算法分析故障原因,并将分析结果推送至地面集控室;远程诊断是由地面集控室工程师或装备制造企业研发人员分析并确认故障原因,并通知巡检人员排除故障。     

基于曙光5000并行机的远程并行调试器

并行调试对并行程序开发非常重要,然而传统的远程并行调试方式是采用登录(telnet)命令通过命令行的文本界面进行,非常繁杂。本文介绍了为曙光3000系统设计实现的远程并行调试器RPB(Remote Parallel Debugger)。RPB实现了完全并行调试等功能,并且具备图形用户界面,用户界面采用Java语言和Swing工具包实现,具备平台独立的特点。RPB采用客户端/服务器模式,客户端和服务器之间的通信采用当今流行的CORBA中间件技术。RPB支持通过局域网或广域网远程调试并行机上的程序,屏蔽了客户平台的差异和并行机地理位置上的差异,因而大大提高了并行机的好用性。     

Giant vortex structures in mesoscopic spherical type-II superconducting samples

Giant vortex states which can occur in type-II mesoscopic spherical superconducting samples embedded in different materials have been studied within the framework of the nonlinear Ginzburg–Landau theory. The proposed method, which is based on presentation of the superconducting order parameter in a form of the spherical functions expansion gives the possibility to take into account different types of boundary condition.     

The adjustment-stabilization method for constrained systems

For constrained system which has several independent first integrals, we give a new stabilization method which named adjustment-stabilization method. It can stabilize all known constants of motion for a given dynamical system very well instead of the stabilization and post-stabilization methods which only conserves one of all first integrals. Further more, new method can improve numerical accuracy too. We also point out the post-stabilization is just a simplest case of the new method.     

Non-Newtonian effects of blood flow in complete coronary and femoral bypasses

A numerical investigation of non-Newtonian steady blood flow in a complete idealized 3D bypass model with occluded native artery is presented in order to study the non-Newtonian effects for two different sets of physiological parameters (artery diameter and inlet Reynolds number), which correspond to average coronary and femoral native arteries. Considering the blood to be a generalized Newtonian fluid, the shear-dependent viscosity is evaluated using the Carreau–Yasuda model. All numerical simulations are performed by an incompressible Navier–Stokes solver developed by the authors, which is based on the pseudo-compressibility approach and the cell-centred finite volume method defined on unstructured hexahedral computational grid. For the time integration, the fourth-stage Runge–Kutta algorithm is used. The analysis of numerical results obtained for the non-Newtonian and Newtonian flows through the coronary and femoral bypasses is focused on the distribution of velocity and wall shear stress in the entire length of the computational model, which consists of the proximal and distal native artery and the connected end-to-side bypass graft.     

Coupled applications on distributed resources

Coupled models are set to become increasingly important in all aspects of science and engineering as tools with which to study complex systems in an integrated manner. Such coupled, hybrid simulations typically communicate data between the component models of which they are comprised relatively infrequently, and so a Grid is expected to present an ideal architecture on which to run them. In the present paper, we describe a simple, flexible and extensible architecture for a two-component hybrid molecular-continuum coupled model (hybrid MD). We discuss its deployment on distributed resources and the extensions to the RealityGrid computational-steering system to handle coupled models.     

基于ASP．NET的自定义规则动态页面自动生成系统的设计与实现

介绍在ASP．NET平台下,一些具有一致功能的模块,可在不需要重复编程的情况下,自动生成与这些功能模块对应的动态页面。对于客户端呈现出的各种不同的动态页面,在应用程序中只需一个特别设计的页面对象类,作为生成实际动态页面的应用基类。该基类不但定义了如何生成动态页面,而且能处理客户端用户提交的不同事件处理需求。     

Fast SIMDized Kalman filter based track fit

Modern high energy physics experiments have to process terabytes of input data produced in particle collisions. The core of many data reconstruction algorithms in high energy physics is the Kalman filter. Therefore, the speed of Kalman filter based algorithms is of crucial importance in on-line data processing. This is especially true for the combinatorial track finding stage where the Kalman filter based track fit is used very intensively. Therefore, developing fast reconstruction algorithms, which use maximum available power of processors, is important, in particular for the initial selection of events which carry signals of interesting physics.One of such powerful feature supported by almost all up-to-date PC processors is a SIMD instruction set, which allows packing several data items in one register and to operate on all of them, thus achieving more operations per clock cycle. The novel Cell processor extends the parallelization further by combining a general-purpose PowerPC processor core with eight streamlined coprocessing elements which greatly accelerate vector processing applications.In the investigation described here, after a significant memory optimization and a comprehensive numerical analysis, the Kalman filter based track fitting algorithm of the CBM experiment has been vectorized using inline operator overloading. Thus the algorithm continues to be flexible with respect to any CPU family used for data reconstruction.Because of all these changes the SIMDized Kalman filter based track fitting algorithm takes 1 μs per track that is 10000 times faster than the initial version. Porting the algorithm to a Cell Blade computer gives another factor of 10 of the speedup.Finally, we compare performance of the tracking algorithm running on three different CPU architectures: Intel Xeon, AMD Opteron and Cell Broadband Engine.     

Scheduling optimization in coupling independent services as a Grid transaction

Due to the dynamic properties of autonomous resource providers, the coupling of independent services as a Grid transaction may abort with inconsistency. In many situations people would resort to compensation actions to regain consistency; consequently there comes the issue of compensation-cost. To handle such an issue, for the first time we set up a costing model for the all-or-nothing transaction of Grid services, and introduce the ECC metric to evaluate related service scheduling. The analysis of ECC estimation is based on the so-called CC-PreC commit pattern, which is an abstract of a category of common use cases of commit handling. Our analysis theoretically illustrates the high degree of computational complexity of scheduling optimization with respect to the cost labeling, timing and order of requests. Under certain typical conditions we prove that infinite possible schemes of scheduling can be reduced down to a finite set of candidates of scheduling. Especially based on the ECC metric, the caution scheduling is thoroughly investigated, which as a basic policy could be employed in certain common scenarios, and under which the intuitive product-first or cost-first schemes are justified in several typical situations.     

Filter diagonalization: Filtering and postprocessing with prolates

A detailed account is given of a recent modification of the Filter Diagonalization technique that serves to analyze a signal spectrum within a selected energy range. Our approach employs for filtering the eigenfunctions of the Finite Fourier Transform, or prolates, which are superior to other filters due to their special properties. In particular, prolates are simultaneously band-limited and highly concentrated at a finite time-interval, producing filters with optimal accuracy. In addition both features are acquired by the convolution of a band-limited function with a prolate, that permits the latter to be interpolated via the Walter and Shen sampling formula, which essentially simplifies the supplementary computations. Rigorous filtering error estimates are obtained. Test calculations illustrate the facilities of the presented modification.     

Piecewise quasilinearization techniques for singular boundary-value problems

Piecewise quasilinearization methods for singular boundary-value problems in second-order ordinary differential equations are presented. These methods result in linear constant-coefficients ordinary differential equations which can be integrated analytically, thus yielding piecewise analytical solutions. The accuracy of the globally smooth piecewise quasilinear method is assessed by comparisons with exact solutions of several Lane-Emden equations, a singular problem of non-Newtonian fluid dynamics and the Thomas-Fermi equation. It is shown that the smooth piecewise quasilinearization method provides accurate solutions even near the singularity and is more precise than (iterative) second-order accurate finite difference discretizations. It is also shown that the accuracy of the smooth piecewise quasilinear method depends on the kind of singularity, nonlinearity and inhomogeneities of singular ordinary differential equations. For the Thomas-Fermi equation, it is shown that the piecewise quasilinearization method that provides globally smooth solutions is more accurate than that which only insures global continuity, and more accurate than global quasilinearization techniques which do not employ local linearization.