共查询到19条相似文献,搜索用时 234 毫秒
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为了能更好地提高水质预报模式中物质输运方程的计算速率,以胶州湾数值预报系统中垂向扩散的串行算法为基础,提出了一种主要针对物质输运方程中的垂向扩散的MPI(message-passinginterface)并行算法。该算法将计算分解为多个子任务,并在基于MPI消息传递模式的集群系统中进行运算。与原串行算法进行比较,并行的加速比提高了33%以上,且并行效率最大可达90%,该结果表明了MPI技术在海洋数值模拟领域应用的潜力。 相似文献
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针对A-SMGCS系统场面活动三维仿真问题,提出一种以开源模拟飞行器FlightGear为场景仿真平台,以实时ADS-B监视数据为驱动,以Linux为操作平台的机场场面活动三维仿真系统设计新方法。仿真系统按照实际机场模型进行机场布局设计,飞机、航站楼、塔台三维建模,地形数据生成,对真实机场环境进行了完整建模。由于ADS-B监视数据缺少飞机姿态信息,提出一种根据位置数据推算出姿态信息的新方法。首先把ADS-B监视数据进行航迹卡尔曼滤波,然后根据飞机前后两个位置的空间连线矢量计算飞行姿态。通过FlightGear多机网络数据接口导入飞机定位数据与姿态数据驱动飞机模型运动,实现了对飞机运动的六自由度仿真。仿真结果表明,该系统能逼真、准确再现真实机场飞机实时活动情况。由于完全基于开源软件设计,该系统低成本实现了对场面活动的实时三维仿真。 相似文献
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在炸药爆破过程的研究中,对炸药爆破过程进行三维仿真,可以预判炸药爆炸的破坏性和冲击气流方向,保证安全.炸药爆破过程中,爆炸产生的冲击波在扩散过程中受到阻挡后,炸药冲击波曲线和形成的冲击涡流状区域被破坏,传统的三维仿真模型在这种无序的爆炸曲线和冲击涡流区域状态下,以牺牲准确性为代价,提取三维参数特征进行仿真,结果偏差较大.提出一种多维约束下的炸药爆破过程仿真方法,分析炸药爆破图形仿真系统的性能和特点,构建优化的炸药爆破三维模型,获取爆破中较为准确的过程线、冲击波曲线与涡流状区域中心的纵间距和横间距比的三维数据,对破坏性数据进行约束评估,实现爆破场景的三维重构,仿真结果说明,改进方法可为对炸药爆破程度进行准确分析提供有效手段. 相似文献
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对我国的低空安全现状及新形势下警务执法工作人员面临的挑战进行了分析,研究了当前警用无人系统的主要装备及其在低空监控、日常巡逻、侦察、取证、快速处置等警务活动中的应用,结合面向低空安全的三维数字化空中走廊技术体系,探索了警用无人系统在报警、接警、执法、处置业务流程中的低空安全防范应用策略。在低空安全防范的数学建模研究中,以无人机违规事件的实时威胁扩散趋势分析中遇到的数据缺失问题为例,根据数据属性值进行了数学建模研究,采用了基于定距型数据和非定距型数据属性的缺失数据估计方法进行缺失数据估计的数学建模。最后,对警用无人系统在低空安全防范中的应用前景进行了展望。 相似文献
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三维GIS模型的分层表示及可视化技术研究 总被引:4,自引:0,他引:4
在分析目前三维GIS建模策略的基础上,根据矿山地质三维数据的特征,提出了三维模型的分层表示策略和基于OpenGL的可视化技术。给定原始的分层数据,结合离散网络模型自动创建控制点之间的拓扑关系,由此建立三维实体的表面模型,加载模型内部属性数据,实现到三维实体模型的转换。然后利用OpenGL造型系统对上述模型进行渲染,进行纹理、光照、消隐、阴影等计算,从而生成高真实感的三维实体模型。最后开发了一套三维GIS仿真系统,并结合实证数据进行了仿真分析。 相似文献
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This research endeavor is focused on the development of SIMBASE to support the construction contractor's decision-malting process regarding the implementation of automation technology into a construction process. SIMBASE is a project-based simulation model integrated with database system. It was developed in order to incorporate the Total Expected Profit (TEP) method. The TEP method, modified from the net present value method, is adopted to justify the automation technology from an economical perspective. SIMBASE simulates cash flows over the life cycle period by calculating total expected profit based on expected income from project bids and expected costs of the technology. Project-based simulation, when compared to activity-based simulation, means that all events in the simulation are generated at the project level, rather than simulating microscopic activities. Since construction activities are mainly comprised of discrete projects, TEP can be calculated on the basis of project bid income versus project cost. SIMBASE was applied to the drilled shaft foundation process for highway bridge construction in the Texas Gulf Coast region. Two cases of drilled shaft foundation processes were simulated in order to represent the characteristics of alternative technologies. The TEP for the selected alternative technology varied, depending on a geological conditions and assumed project bid winning ratio. 相似文献
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安全壳是核电工业中用于保护核反应堆运转的重要安全设备,对安全壳相关的测量数据或仿真数据进行可视化,有助于及时发现其中可能潜在的安全问题.根据安全壳的形状特征,提出一种基于圆柱坐标系的网格划分方法及物理量数据可视化表达方法.通过设定圆柱坐标系下的单一维度坐标,实现网格单元划分的横截面与纵剖面的直观显示.使用八叉树组织存储网格单元,有效地改善了存储性能,提升了网格单元查找速度.通过设定圆柱坐标系下的单个或多个维度坐标,实现了基于时间或空间变化的多种截线图、截面图的可视化显示.实验结果表明,该方法可实时显示安全壳的运转状况,有效地模拟安全壳运行的物理规律,确保核电站反应堆的安全. 相似文献
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D. W. Pepper 《Computers & Fluids》1980,8(4):371-390
The numerical solution of the three-dimensional pollutant transport equation is obtained with the method of fractional steps; advection is solved by the method of moments and diffusion by cubic splines. Topography and variable mesh spacing are accounted for with coordinate transformations. First estimate wind fields are obtained by interpolation to grid points surrounding specific data locations. Mass consistency is ensured by readjusting the three-dimensional wind field with a Sasaki variational technique. Numerical results agree with results obtained from analytical Gaussian plume relations for ideal conditions. The numerical model is used to simulate the transport of tritium released from the Savannah River Plant on 2 May, 1974. Predicted ground level air concentration 56 km from the release point is within 38% of the experimentally measured value. 相似文献
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《Environmental Software》1994,9(3):175-187
This paper describes a numerical modeling approach that can be used to provide estimates of emissions at industrial sites. In particular the models presented are capable of simulating the wind flow and dispersion of airborne pollutants around surface-mounted structures such as buildings or building complexes. The calculational procedure in this approach consists of two sequential steps, namely: (i) prediction of the mean flow via a turbulent flow model; and (ii) employment of the calculated flow field to drive a particle-in-cell transport and diffusion model. A benchmark simulation is performed in which numerical results from the flow model are compared with other numerical models and with experimental data for flow over a backward-facing step. Results from three-dimensional simulations of flow and dispersion over a two-building complex are also presented. 相似文献
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建立了密闭空间内的气体在通风条件下的泄漏对流扩散数学模型,介绍了其有限元模型,详细描述了该仿真系统的结构框架图,具体给出了密闭空间内的气体在通风条件下的泄漏对流扩散时的节点浓度曲线图和两个截面的浓度色图。仿真结果对于建立该密闭空间内的气体浓度安全监控系统具有重要的指导作用。 相似文献
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本文介绍一种以PCI数据采集卡为核心的控制系统的设计,它以LabVIEW为仿真监测平台,以Visual C 设计上层软件控制系统,文中探讨了如何利用LabVIEW配合系统开发,监测在目标软件控制系统控制下PCI卡的输入输出信号,便捷,安全并可靠的实现一个以步进电机为主要控制对象的立体照片成像系统。 相似文献
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基于高斯扩散模型的化工危险品泄露区域计算及其实现 总被引:1,自引:0,他引:1
化工危险品在生产储运过程中会引发泄漏扩散事故,对它的泄露扩散进行模拟,可以及时、准确、有效、直观地对事故过程的危险区域做出预测,并以此为依据制定相应的应急措施。以高斯扩散模型为核心,结合化工危险品数据库、地理信息系统GIS等现代计算机辅助技术对化工危险品扩散的短时间接触容许浓度范围、半致死浓度范围等指标进行科学的量化计算以及对泄漏事故进行技术模拟预测,并且成功的应用于实际项目中。 相似文献
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Studies of worm outbreaks have found that the speed of worm propagation makes manual intervention ineffective. Consequently, many automated containment mechanisms have been proposed to contain worm outbreaks before they grow out of control. These containment systems, however, only provide protection for hosts within networks that implement them. Such a containment strategy requires complete participation to protect all vulnerable hosts. Moreover, collaborative containment systems, where participants share alert data, face a tension between resilience to false alerts and quick reaction to worm outbreaks.This paper suggests an alternative approach where an autonomous system in an internetwork, such as the Internet, protects not only its local hosts, but also all hosts that route traffic through it, which we call internetwork-centric containment. Additionally, we propose a novel reputation-based alerting mechanism to provide fast dissemination of infection information while maintaining the fairness of the system. Through simulation studies, we show that the combination of internetwork-centric containment and reputation-based alerting is able to contain an extremely virulent worm with relatively little participation in the containment system. In comparison to other collaborative containment systems, ours provides better protection against worm outbreaks and resilience to false alerts. 相似文献