在地震减灾仿真网格系统中数据网格应用技术研究

有效地定位、访问、浏览数据是异构广域网络中急需解决的问题,数据网格技术是解决此问题的有效手段之一。通过运用虚拟化的元数据模型,并在其基础上提出了单一的数据访问接口,同时运用单一的数据访问接口构建了元数据目录服务系统,最后在地震减灾仿真网格系统中应用该设计思想实现了地震数据的有效管理。     

基于OGSA的地震网格监控系统研究

地震网格利用网格技术将地理上分布的各种地震实验设备和现场、数据、人员联结起来,构成一个虚拟的地震研究社区.有效地监控可以促进网格系统的合理开发和部署,提高网格管理水平和资源利用率.分析和比较了端.端、网格监控系统体系结构(GMA)和开放网格体系结构(OGSA)等几种框架,给出了基于OGSA的地震网格监控系统的总体结构,最后对实现的关键技术进行了探讨.     

Web-based distributed system and database modeling for concurrent design

This research introduces a new approach for Web-based collaborative concurrent design. In this approach, systems, product libraries, and product databases for modeling different product development life-cycle aspects are distributed at different locations that are linked through the Web. Product modeling libraries are described as class features. A class feature at a remote location can be used for defining a new class feature at the local site. Product modeling systems distributed at different locations are used for creating product databases that are described by instance features. A system at one location can be implemented using the functions provided at other locations as the components. Different life-cycle databases at different locations are associated by their relations. The optimal design considering relevant life-cycle aspects is identified using the distributed product life-cycle modeling systems and databases.     

Deploying Web-based visual exploration tools on the grid

Grid-based computing facilitates access to different resources. But management in a grid-based environment isn't centralized. To use grid resources effectively, researchers need a central access point to manage the resources, provide a visual means to explore the data, and record these explorations for further investigation and dissemination. This article describes such a system that's being developed jointly by the University of California, Davis, and the Lawrence Berkeley National Laboratory (LBNL). The centralized system acts as a portal into grid-enabled visualization systems. Scientists using the portal can focus on the important task of extracting insights from their data through visualization instead of having to worry about process management. Because scientists at LBNL and their collaborators require access to the portal from around the world, the portal's interface is entirely Web-based. Authenticated users only need a standards-compliant Web browser to explore their data from anywhere in the world. The portal provides a Web-based interface not just for exploring but also for encapsulating visualization data. Encapsulating the process lets users reproduce the visualization results for validation or extend those results by continuing data exploration. We discuss the integration of our grid-enabled visualization server, the visualization Web application that performs the visualization session management, and the Web-based interface.     

BLDC伺服系统控制系统建模与仿真

在分析了永磁无刷直流电机（BLDC）基本运行原理的基础上,建立了BLDC的数学模型,并在MATLAB7.1环境下搭建了伺服系统的双闭环控制系统仿真模型,实验结果表明,该模型在BLDC伺服系统的控制中性能稳定可靠,有较高的实用价值。     

基于Petri网的FMS物流系统建模与仿真

在建立FMS物流系统Petri网模型的基础上,采用“映射”思想,将Petri网模型转化为物流系统的仿真程序,提出了库所映射为程序数据、变迁映射为程序函数、系统子网映射为FMS系统基本类的映射方法,通过实例仿真验证了软件程序与模型的一致性。     

网格调度仿真测试环境中自动机模型的研究

网格调度仿真测试环境通过模拟广域范围内的异构资源以及网格中间件的部分功能,为网格调度算法提供了测试环境.自动机模型来源于形式语言与自动机领域,在GridSim的基础上应用自动机模型,设计了仿真处理自动机实现了模拟过程的状态化,使得仿真测试环境具有了层次清晰、可配置和可扩展等优点.     

地震网格数据采集与遥现系统设计

数据采集与遥现是地震网格的重要功能,它负责从数据采集设备获取实验数据并传递给远程的实验参与者.分析了开放网格体积结构(OGSA)和数据流服务工具包令牌缓冲网络总线(RBNB),提出了地震网格数据采集与遥现系统的总体框架和工作流程,对数据采集系统的网格服务工厂(GRSF),网格服务实例(GRSI)、对象映射等实现中的关键技术进行了探讨.     

网格环境下的数据库系统

网格计算是一种重要的新技术,网格上的大量数据需要使用数据库系统来管理。在介绍了与网格环境下数据库系统相关的研究工作之后,讨论了网格数据库的研究内容,包括网格数据库管理系统、网格数据库集成和网格应用的新需求。建议数据库研究人员对网格数据库作更多的研究,致力于从网格应用中发现并解决网格数据库面临的新问题。     

Unsupervised feature selection and general pattern discovery using Self-Organizing Maps for gaining insights into the nature of seismic wavefields

This study presents an unsupervised feature selection and learning approach for the discovery and intuitive imaging of significant temporal patterns in seismic single-station or network recordings. For this purpose, the data are parametrized by real-valued feature vectors for short time windows using standard analysis tools for seismic data, such as frequency-wavenumber, polarization, and spectral analysis. We use Self-Organizing Maps (SOMs) for a data-driven feature selection, visualization and clustering procedure, which is in particular suitable for high-dimensional data sets. Our feature selection method is based on significance testing using the Wald–Wolfowitz runs test for individual features and on correlation hunting with SOMs in feature subsets. Using synthetics composed of Rayleigh and Love waves and real-world data, we show the robustness and the improved discriminative power of that approach compared to feature subsets manually selected from individual wavefield parametrization methods. Furthermore, the capability of the clustering and visualization techniques to investigate the discrimination of wave phases is shown by means of synthetic waveforms and regional earthquake recordings.     

制造网格环境下的资源建模研究

资源建模是制造网格中资源集成和共享的前提.首先按资源在制造网格中提供的服务类型对其进行了分类,便于对其分类建模.其次提出了由资源层、资源表示层和资源接口层组成的资源层次模型.资源层包括各种物理资源,表示层使用XML Schema封装资源数据和信息,接口层使用Web服务描述语言（WSDL）定义对资源的访问操作.该模型用于将制造资源封装为网格节点,使得制造资源可以方便地接入网格中网络共享.最后以企业标准件库的封装为实例验证了该模型的有效性.     

智能电网监控运行大数据分析系统统一建模方法研究

随着电网监控运行一体化运行趋势愈发明显,大数据技术应用的不断成熟、普及,为具有多源、高维、异构等特征的电网监控大数据的分析与应用提供了解决方案。本文提出了面向智能电网监控运行大数据分析系统的统一建模方法,分析了监控大数据的数据源、数据范围及现状与存在问题,指出了数据建模所需解决的问题与思路,采用元数据思想构建了公共模型,基于业务需要构建了应用模型,对于数据接入与存储管理方面,定义了元数据模型,其目的是在接入、汇总监控业务相关数据源的基础上,构建以设备为中心的监控数据关联模型,实现数据对象统一建模,为实现多源数据高效、规范接入提供了模型支撑,同时定义了符合该建模思路的元模型,元模型约束了建模行为,保证建立的模型遵行领域约束,为上层智能监控大数据分析应用奠定了基础。     

ACE—A FORTRAN subroutine for analytical computation of effective grid parameters for finite-difference seismic waveform modeling with standard Earth models

Despite the broad use of the heterogeneous finite-difference (FD) method for seismic waveform modeling, accurate treatment of material discontinuities inside the grid cells has been a serious problem for many years. One possible way to solve this problem is to introduce effective grid elastic moduli and densities (effective parameters) calculated by the volume harmonic averaging of elastic moduli and volume arithmetic averaging of densities in grid cells. This scheme enables us to place a material discontinuity in an arbitrary position in the spatial grids.Standard Earth models have made a significant contribution to synthetic seismogram calculations with a variety of numerical procedures such as the FD method. For the FD computation of seismic waveform with these models, we must first ensure accurate treatment of material discontinuities in the radius (or depth). The present paper introduces a FORTRAN subroutine ACE which calculates effective parameters analytically for an arbitrary spatial region in either the radius or depth direction for four major standard Earth models, namely, the PREM, IASP91, SP6, and AK135. This program is intended for all FD users who are concerned with seismic wave simulation for these models.     

Performance modeling of parallel applications for grid scheduling

Grids consist of both dedicated and non-dedicated clusters. For effective mapping of parallel applications on grid resources, a grid metascheduler has to evaluate different sets of resources in terms of predicted execution times for the applications when executed on the sets of resources. In this work, we have developed a comprehensive set of performance modeling strategies for predicting execution times of parallel applications on both dedicated and non-dedicated environments. Our strategies adapt to changing network and CPU loads on the grid resources. We have evaluated our strategies on 8, 16, 24 and 32-node clusters with random loads and load traces from a grid system. Our strategies give less than 30% average percentage prediction errors in all cases, which, to our knowledge, is the best reported for non-dedicated environments. We also found that grid scheduling using predictions of execution times from our performance modeling techniques will lead to perfect mapping of applications to resources in many cases.     

A knowledge-based environment for modeling and simulating softwareengineering processes

The design and representation schemes used in constructing a prototype computational environment for modeling and simulating multiagent software engineering processes are described. This environment is called the articulator. An overview of the articulator's architecture identifying five principal components is provided. Three of the components, the knowledge metamodel, the software process behavior simulator, and a knowledge base querying mechanism, are detailed and examples are included. The conclusion reiterates what is unique to this approach in applying knowledge engineering techniques to the problems of understanding the statics and dynamics of complex software engineering processes     

网格环境下机载导弹远程测试软件建模

随着技术的发展,机载导弹的维护变得越来越复杂.远程测试是由专家指导维护人员或者由专家直接对机栽导弹进行测试,定位故障.针对远程测试中碰到的防火墙阻塞,平台不独立等问题,提出了基于网格的远程测试.并在分析远程测试中可能发生时序错乱,网络延时等问题的基础上,建立了机载导弹远程测试软件模型.     

Intelligent Web-based education system for adaptive learning

This paper depicts a set of integrated tools to build an intelligent Web-based education system. Our purpose is to create a Web learning environment that can be tailored to the Learners’ needs. The Web learning environment is composed of Authoring Tool, Evaluation System, Interactive Voice System and a Virtual Laboratory for programming in Java. All tools use Web Services and have the characteristics of powerful adaptability for the management, authoring, delivery and monitoring of learning content. Part of the decision-making inside the intelligent Web-based education system was made with a multi-agent system.     

An evolving system for simulating clothes on virtual actors

This cloth modeling and animation system aims to support virtual actors who can dress and undress themselves. It now creates autonomous clothes, independent of the synthetic human wearing them. The interactive editor, proportion box and body-scaling feature provide a set of intuitive tools for animators to design a rich variety of human shapes, and we have shown how to dress them with autonomous clothes. The new software considerably improves system performance, versatility and ease of use, and our goal of simulating actors that can dress and undress themselves is significantly closer     

智能电网快速仿真与模拟任务调度优化方法

基于MAS建立的分布并行计算环境,其任务调度问题具有新的特点。对于基于MAS的配电快速仿真与模拟系统,以配电网三相状态估计为例,建立了新的调度问题模型,提出了基于FCM的启发式任务调度优化方法。该方法利用模糊C均值聚类分析算法对独立任务进行聚类分析,避免了在超大解空间中用基于搜索的方法去寻求最优解的做法。该方法具有线性时间复杂度,而且通过大量算例表明它总是能够在合理的时间内获得次优解或最优解,使masDSE的性能有明显改善。     

The simpler GMRES method combined with finite volume method for simulating viscoelastic flows on triangular grid

An efficient solver integrating the restarted simpler generalized minimal residual method (SGMRES(m)) with finite volume method (FVM) on triangular grid is developed to simulate the viscoelastic fluid flows. In particular, the SGMRES(m) solver is used to solve the large-scale sparse linear systems, which arise from the course of FVM on triangular grid for modeling the Newtonian and the viscoelastic fluid flows. To examine the performance of the solver for the nonlinear flow equations of viscoelastic fluids, we consider two types of numerical tests: the Newtonian flow past a circular cylinder, and the Oldroyd-B fluid flow in a planar channel and past a circular cylinder. It is shown that the numerical results obtained by the SGMRES(m) are consistent with the analytical solutions or empirical values. By comparing CPU time of different solvers, we find our solver is a highly efficient one for solving the flow equations of viscoelastic fluids.