VizLitG: Grid Visualization e-Service Enabling Partial Dataset Transfer from Storage Elements of gLite-based Grid Infrastructure

Grid visualization e-service VizlitG is developed for Lithuanian grid infrastructure based on gLite middleware. The client–server architecture of the e-service VizLitG is based on widely recognized web standards implemented in Java EE 6 platform and GlassFish application server. VizLitG is designed for convenient access and interactive visualization of remote data files located in storage elements of gLite-based grid infrastructure. Partial dataset transfer from the experimental storage element is developed in order to reduce the communication time and achieve interactive rates. The performance of VizLitG is evaluated visualizing poly-dispersed particle systems of different sizes in a geographically distributed grid. The attention is focused on the performance of data transfer from the storage elements and its contribution to the total benchmark time. Different types of software are employed for data transfer in order to present the quantitative comparison.     

基于VTK的CFD数据可视化Grid Service设计和实现

应用可视化工具VTK和Java在网格计算环境下实现了一个用于CFD数据后处理的高效率、易扩展、实用的可视化网格服务。网格服务接口用Web服务语言(WSDL)描述,网格服务内部实现使用VTK作为可视化内核,构建网格环境的中问件系统使用的是基于OGSA的GT3。实验结果表明,可视化网格服务可以充分利用远程强大计算资源,为性能较弱的客户端提供强大的可视化处理能力。     

Diffusion tensor visualization with glyph packing

A common goal of multivariate visualization is to enable data inspection at discrete points, while also illustrating larger-scale continuous structures. In diffusion tensor visualization, glyphs are typically used to meet the first goal, and methods such as texture synthesis or fiber tractography can address the second. We adapt particle systems originally developed for surface modeling and anisotropic mesh generation to enhance the utility of glyph-based tensor visualizations. By carefully distributing glyphs throughout the field (either on a slice, or in the volume) into a dense packing, using potential energy profiles shaped by the local tensor value, we remove undue visual emphasis of the regular sampling grid of the data, and the underlying continuous features become more apparent. The method is demonstrated on a DT-MRI scan of a patient with a brain tumor.     

基于网格数据图的自适应细分及边缘提取

文章针对网格数据计算的可视化表达,给出了网格数据图有限元自适应细分方法;进而提出了网格计算与图形及数字图像处理的信息融合提取算法,实现了数据的自适应采样细分、图像分割与边缘提取。实验结果表明,该方法在不增加太多的计算及数据量情况下,可以很好地提高特征区域数据分辨率和网格数据计算的效率。     

Progress in grid generation via the advancing front technique

We describe recent extensions and improvements to the advancing front grid generation technique. These improvements target a range of applicability, speed and user friendliness. The range of applicability is enlarged by the ability to produce volumetric grids around thin surfaces (such as shells, membranes, fabrics or surfaces with cusps), the generation of high aspect ratio grids for Navier-Stokes applications, the generation of higher order triangular and tetrahedral elements, and the generation of quadrilateral and hexahedral elements. Speed improvements are the result of reduced search overheads, as well as vectorization and parallelization. User friendliness is enhanced by the ability to grid directly discrete data and simpler ways of specifying the desired element size and shape in space. Numerous examples are included that demonstrate the versatility and maturity that advancing front grid generators have achieved.     

网格信息服务互操作策略研究

针对当前网格中间件中信息服务系统的差异性和不可互操作性,提出了一种基于插件和虚拟层的网格信息服务互操作策略。该策略可以屏蔽底层网格中间件信息服务部件的异构性,为终端用户和作业调度模块提供统一的服务访问接口。通过在CSGrid网格互操作项目中的成功应用,该策略体现了以下特点:可在互操作的同时,保证各网格系统的独立性;只需开发一些插件就可扩展到更多的网格平台,具有良好的可扩展性;能够提供一定的可靠性保证和服务质量保证。     

语义Web和语义网格及数据资源整合的探讨

目前,许多电子政务系统面临着一个共同的问题,这就是所谓的＂信息孤岛＂问题,解决该问题的关键是如何将现有数据资源进行有效的整合。而语义网格理论的提出,为这一难题的解决提供了一个新的思路。应用语义网格理论,针对出租汽车管理信息化的应用需求,构造语义网格模型Tx-Grid,并且讨论一种利用本体整合分布式异构数据库资源的机制,有效地解决这一问题。     

混合型网格上基于Access Grid的协同可视化平台

近些年来,AccessGrid(AG)发展得十分迅速,它已经成为人们进行高级合作、组与组之间会议、教学和研究等的最流行工具之一。论文首先介绍了AG的体系结构及所涉及的各种关键技术,然后详细描述了如何在作者所搭建的一个基于GlobusToolkit(GT)和SunGridEngine(SGE)的Cluster网格环境上借助AccessGrid来搭建一个协同可视化的平台。     

Grid automata and supervisory control of dense real-time discrete event systems

We present a generalization of the classical supervisory control theory for discrete event systems to a setting of dense real-time systems modeled by Alur and Dill timed automata. The main problem involved is that in general the state space of a timed automaton is (uncountably) infinite. The solution is to reduce the dense time transition system to an appropriate finite discrete subautomaton, the grid automaton, which contains enough information to deal with the timed supervisory control problem (TSCP). The plant and the specifications region graphs are sampled for a granularity defined in a way that each state has an outgoing transition labeled with the same time amount. We redefine the controllability concept in the context of grid automata, and we provide necessary and sufficient solvability conditions under which the optimal solution to centralized supervisory control problems in timed discrete event systems under full observation can be obtained. The enhanced setting admits subsystem composition and the concept of forcible event. A simple example illustrates how the new method can be used to solve the TSCP.     

GridMol:一个基于网格的分子可视化系统

介绍了一个基于网格环境、支持大分子显示的远程可视化系统GridMol。系统采用Browser-Server结构,客户端采用Java3D实现,服务器端使用面向对象方法实现了支持多种文件格式的数据处理,同时采用了特定的数据格式以减小网络数据传输。整个系统置于网格环境下,用户通过ChinaGrid的VisPortal进行访问。     

MVSMg:一个基于网格的计算燃烧学可视化共享模型

提出了一种基于网格的计算燃烧学可视化共享模型MVSMg（Multilevel Visualization and Storage Model based on grid）,并给出了形式化定义。模型将共享分为静态共享和动态共享。网格环境下计算燃烧学的数据可视化分为多级,帮助领域专家进行不同深度的研究。对好的应用模块进行注册,并与处理所得数据一起分层存储．以利于其他用户共享。还提出了一个动态共享和注册管理算法。最终实现了数据和应用模块的共享,避免了重复开发和计算。     

基于知识网格的数据挖掘

工业、科学、商务等领域的数据通常分布在不同的地方,需要在不同的地点对其进行分布式维护。只有使用计算功能超强的分布式、并行处理系统才能分析这些领域所产生的超大规模数据集。网格为分布式知识发现应用中的计算提供了有效支持。为了在网格上进行数据挖掘的开发,本文提供了一个称之为知识网格的系统,讨论如何应用知识网格设计实施数据挖掘应用,并说明如何搜索网格资源、编制软件和数据组件,以及数据挖掘应用在网格上的执行过程。     

网格环境下银河系铁元素丰度梯度的统计分析

铁元素丰度梯度统计分析是网格环境下银河系化学演化研究的一个重要内容,作为虚拟天文台应用系统中在大量数据资源的基础上开展深层次的分析和处理的一个示例。网格环境下银河系铁元素丰度梯度的统计分析实现包括注册服务、数据服务、恒星轨道计算服务和可视化服务等网格服务,组成一个完整的网格应用系统。该文详细描述了数据服务、轨道计算服务和可视化服务的设计和实现,示例展示了在分布、异构和动态的网格环境下,如何通过网格服务的方式有效地实现资源共享和科学数据的高效利用。     

一个网格经济学模型和信用机制

网格的目标是实现对地理上广泛分布的大量异构资源进行共享.然而,由于网格具有的异构性、分布性和动态性,网格环境中的资源管理是个复杂的问题.将经济学原理,例如一些经济学模型和市场机制引入网格之中构建网格经济学资源管理模型,能够很好地配合网格的离散特性.该文将经济学原理引入网格环境之中,提出了一个“信用机制”,使用户能够根据服务提供者的“信用”来优化选择,同时使网格更为高效和有序.     

An in-core grid index for transferring finite element data across dissimilar meshes

The simulation of a manufacturing process chain with the finite element method requires the selection of an appropriate finite element solver, element type and mesh density for each process of the chain. When the simulation results of one step are needed in a subsequent one, they have to be interpolated and transferred to another model. This paper presents an in-core grid index that can be created on a mesh represented by a list of nodes/elements. Finite element data can thus be transferred across different models in a process chain by mapping nodes or elements in indexed meshes. For each nodal or integration point of the target mesh, the index on the source mesh is searched for a specific node or element satisfying certain conditions, based on the mapping method. The underlying space of an indexed mesh is decomposed into a grid of variable-sized cells. The index allows local searches to be performed in a small subset of the cells, instead of linear searches in the entire mesh which are computationally expensive. This work focuses on the implementation and computational efficiency of indexing, searching and mapping. An experimental evaluation on medium-sized meshes suggests that the combination of index creation and mapping using the index is much faster than mapping through sequential searches.     

网格体系结构、关键技术及其应用*

网格是信息社会的网络基础设施,是下一代Web技术。通过介绍网格概念、特点,阐述了网格的组成与体系结构,诠释了网格系统的关键技术,分析了几个网格系统,最后讨论了网格的应用领域。     

网格环境下清空型调度策略应用研究

在网格计算中,资源的调度优化特别是请求的调度优化是一个关键技术问题,引入离散事件动态系统中的水箱型混合动态系统模型,对网格上的资源和请求进行一体化建模。清空型调度策略是混合动态系统中一类重要的调度策略,研究了它在网格环境下的应用性能,提出一种推广形式。重点研究系统模型的建立和调度策略的稳定性分析,给出稳定性证明的理论推导过程和仿真实验结果。为下一代网络中的数据管理提供了一种新思路。     

基于离散粒子群和禁忌搜索的网格资源调度算法

提出一种基于智能的网格资源分配和任务调度算法,由于网格资源调度是个离散问题,所以采用基于惯性权重的离散粒子群算法,针对离散粒子群算法在后期容易陷入局部最优的缺陷,将其与禁忌搜索算法相结合,在算法的前期采用离散粒子群算法进行搜索,在后期采用禁忌搜索算法进行局部搜索。并利用网格模拟工具Gridsim Toolkit开发一个网格模拟系统进行实验。实验结果表明,该算法具有较高的寻优能力。     

飞行器外型设计遗传优化算法的网格实现

飞行器外型设计遗传优化算法网格计算系统是基于网格技术的。该系统由一组网格服务所构成。遗传算法中的流场计算模块（CFD)在该系统中是以服务的方式提供并可运行在各种计算机上。在该系统中，能够动态地发现和利用计算机资源，这些资源可以是异构的机型，可以是不同操作系统，井且这些资源的位置也可以是广域分布的。这个系统，为飞行器外型设计提供了更加灵活的设计手段，比如对设计过程的监控和控制，多用户协作设计等。