System of Grid Resource Monitoring Service

Resource monitoring is a key component in grid system. It can help understanding the performance limits and forecasting the failure of the system, advice in the scheduling and configuration of grid application and so on. This paper puts forward a system of grid resource monitoring service which is based on MDS （Monitoring and Discovery Service）, which achieves real-time monitoring and the visualization of historical monitoring data for computing nodes in grid by Globus Toolkits. It introduces the design ideas of this service system, presents its architecture, and discusses its supports for low delay, low performance affection, scalability and manageability.     

基于AccessGrid的视频会议

This paper first describes the Grid concept and its current research status. Access Grid is a complement of computational grid. This paper gives a deep analysis of Access Grid and gives a basic model of it. After describing the Access Grid Node‘s software and hardware configuration and deployment, this paper explains how to manage events on the Access Grid. Lastly, this paper gives some new directions that Access Grid research works are going on.     

Usability Issues of Grid System Software

This paper addresses the problem why grid technology has not spread as fast as the Web technology of the 1990＇s. In the past 10 years, considerable efforts have been put into grid computing. Much progress has been made and more importantly, fundamental challenges and essential issues of this field are emerging. This paper focuses on the area of grid system software research, and argues that usability of grid system software must be enhanced. It identifies four usability issues, drawing from international grid research experiences. It also presents advances by the Vega Grid team in addressing these challenges.     

A grid middleware for distributed Java computing with MPI binding and process migration supports

“Grid” computing has emerged as an important new research field. With years of efforts, grid researchers have successfully developed grid technologies including security solutions,resource management protocols, information query protocols, and data management services. How-ever, as the ultimate goal of grid computing is to design an infrastructure which supports dynarnic,cross-organizational resource sharing, there is a need of solutions for efficient and transparent task re-scheduling in the grid. In this research, a new grid middleware is proposed, called G-JavaMPI. This middleware adds the parallel computing capability of Java to the grid with the support of a Grid-enabled message passing interface (MPI) for inter-process communication between Java processes executed at dif-ferent grid points. A special feature of the proposed G-JavaMPI is the support of Java process migration with post-migration message redirection. With these supports, it is possible to migrate executing Java process from site to site for continuous computation, if some site is scheduled to be turned down for system reconfiguration. Moreover, the proposed G-JavaMPI middleware is very portable since it requires no modification of underlying OS, Java virtual machine, and MPI package. Preliminary performance tests have been conducted. The proposed mechanisms have shown good migration efficiency in a simulated grid environment.     

New theoretical framework for OFDM/CDMA systems with peak-limited nonlinearities

A new theoretical framework for the evaluation of the in-band nonlinear distortion effects on the performance of OFDM systems is presented. In contrast to previous works that approximate the nonlinear noise as a Gaussian additive random process, the new framework is based on the properties of the large deviations of a stationary Gaussian process and shot noise theories, which can evaluate the performance of the OFDM system with high accuracy, especially at realistic scenarios where the Gaussian approximation of the nonlinear noise is no longer valid. The approach can be used to evaluate many communication systems with peak-limited nonlin-earities and high PAPR, such as the downlink performance analysis of large ca-pacity DS-CDMA systems.     

Co-Simulation of an SRG Wind Turbine Control and GPRS/EGPRS Wireless Standards in Smart Grids

Wind energy can be considered a push-driver factor in the integration of renewable energy sources within the concept of smart grids.For its full deployment,it requires a modern telecommunication infrastructure for transmitting control signals around the distributed generation,in which,the wireless communication standards stand out for employing modern digital modulation and coding schemes for error correction,in order to guarantee the power plant operability.In some developing countries,such as Brazil,the high penetration of commercial mobile wireless standards GPRS and EGPRS(based on GSM technology)have captivated the interests of the energy sector,and they now seek to perform remote monitoring and control operations.In this context,this article presents a comparative performance analysis of a wireless control system for a wind SRG,when a GPRS or EGPRS data service is employed.The system performance is analyzed by co-simulations,including the wind generator dynamics and the wireless channel effects.The satisfactory results endorse the viability and robustness of the proposed system.     

CROWN:A service grid middleware with trust management mechanism

Based on a proposed Web service-based grid architecture, a service grid middleware system called CROWN is designed in this paper. As the two kernel points of the middleware, the overlay-based distributed grid resource management mechanism is proposed, and the policy-based distributed access control mechanism with the capability of automatic negotiation of the access control policy and trust management and negotia- tion is also discussed in this paper. Experience of CROWN testbed deployment and ap- plication development shows that the middleware can support the typical scenarios such as computing-intensive applications, data-intensive applications and mass information processing applications.     

Stability analysis for a second-order continuous finite-time control system subject to a disturbance

In this paper, using finite-time control method, we consider the disturbance analysis of a second-order system with unknown but bounded disturbance. We show that the states of the second-order system will be stabilized to a region containing the origin. The radius of this region is determined by the control parameters and can be rendered as small as desired. The rigorous stability analysis is also given. Compared with the conventional PD control law, the finite-time control law yields a better disturbance rejection performance. Numerical simulation results show the effectiveness of the method.     

ACO-Steiner: Ant Colony Optimization Based Rectilinear Steiner Minimal Tree Algorithm

The rectilinear Steiner minimal tree （RSMT） problem is one of the fundamental problems in physical design, especially in routing, which is known to be NP-complete. This paper presents an algorithm, called ACO-Steiner, for RSMT construction based on ant colony optimization （ACO）. An RSMT is constructed with ants＇ movements in Hanan grid, and then the constraint of Hanan grid is broken to accelerate ants＇ movements to improve the performance of the algorithm. This algorithm has been implemented on a Sun workstation with Unix operating system and the results have been compared with the fastest exact RSMT algorithm, GeoSteiner 3.1 and a recent heuristic using batched greedy triple construction （BGTC）. Experimental results show that ACO-Steiner can get a short running time and keep the high performance. Furthermore, it is Mso found that the ACO-Steiner can be easily extended to be used to some other problems, such as rectilinear Steiner minimal tree avoiding obstacles, and congestion reduction in global routing.     

基于网络断层扫描的网格网络性能测量分析

网格计算通过网络连接来获得一个高性能和高效的计算平台。网格网络的监测和性能测量为网格性能分析、负载平衡、任务调度等提供了重要的科学依据,而成为大规模网格服务的关键组件。现有的几种网格监测方法因缺乏对监测数据的推断分析而无法对网格网络的性能进行测量。通过对网格网络性能测量的特点、GloPerf及传统网络测量技术的分析,提出了基于网络断层扫描的网格网络性能测量方法。研究结果为网格网络性能的测量提供了新的途径。     

织女星网格的体系结构研究

网格技术是高性能计算机研究的热点，网格的体系结构是构建网格系统的基础，在分析比较现有网格技术的基础上，提出了织女星网格的体系结构设计，并对其中的关键问题进行了研究，织女星网格体系结构的基本思路是实现一台虚拟的、单一的网格超级计算机，其核心是Vege设计思想，织女星网格体系结构的关键组成包括网格硬件、网格互联系统以及网格操作系统，同时提出了资源路由器、网格计算协议、网格浏览器等重要概念。     

电力网格通信方式的研究和实现

电力网格是网格技术和电力监控与自动化调度技术结合发展的产物.网格技术对于网络上的各种资源具有巨大的整合能力,电力网格能解决现有电力系统中存在的一些问题.同时,电力网格作为网格技术的新应用,它给网格技术的发展带来了新的研究背景和发展方向.但是电力系统有其特殊性,并非所有的网格技术都可以不加变化地照搬到电力网格中.电力网格对数据通信的实时性、兼容性和开放性有比较高的要求.针对电力网格的以上特点,分析了传统网格通信方式在电力网格应用中的困难.最后,根据电力网格的一个应用范例--PGP平台,提出了自己的解决方案,并验证了该方案的技术可行性.     

面向多自治域网格的信息服务模型及其实现

网格是实现分布异构资源共享的有效模式,而信息服务实现系统服务与资源的有效管理,是网格系统的重要组成部分.ChinaGrid是由多个自治域组成的大规模网格,现有的信息服务不能满足此类系统特性与应用需求.文中提出网格信息服务体系GISA2.0,强化了域自治管理和资源信息的安全性.GISA2.0实现了可扩展的网格信息模型和面向服务、支持多种监控信息聚集的层次化信息管理框架.提出了基于分布XPath引擎的多域资源信息检索机制,实现了安全、快速和用户相关的虚拟全局资源视图.     

基于经济机制的资源管理与网格经济研究进展

本文通过回顾网格计算的特点,阐述了基于经济机制的资源分配在网格计算中的重要性和优势,分析了建立基于经济机制的网格系统所需的必要条件,通过比较有代表性的基于经济机制的资源管理系统和工作,以及参考相关的网格协议,如网格经济服务框架（GESA）等,指出了网格经济研究和实施中面临的问题与发展的方向。     

计算经济中的网格监测体系结构

网格监测是实现网格资源有效调度的基础,它采集、传输和分析各种资源的运行数据,由此实现性能评估、错误发现以及预测等,最终改善系统的性能。针对网格资源管理中的计算经济模型,提出了一个4层的网格监测体系结构;设计了监测中的数据处理管理、监测数据交换;对体系结构中的模块组成和实现问题进行了讨论,在GRACE上实现了原型系统。通过实验证明实现的监测体系结构是有效的。     

基于GMA的层次化网格资源信息服务研究与实现

网格资源信息服务(GRIS)是网格基础结构的关键组成部分，它定义了一套发现和监控网格资源的机制，并以此为网格上层应用提供服务，如故障检测、性能分析、任务调度等。资源信息的准确获取、有序管理和高效检索是其中的关键技术问题。基于GMA体系结构，文章提出了一种对网格资源信息进行层次化组织管理的方法，并面向Windows平台，设计实现了基于该方法的网格资源信息服务系统。论文研究成果已在工程项目中得到实际应用。     

基于有向无环图的两层网格监测系统

资源监测系统是网格实现中的重要一环，Global Grid Forum已提出用网格监测体系结构（grid monitoring architecture,GMA）来解决这些问题，在此基础上，提出一种基于有向无环图的两层资源监测系统（DTGMS）。该系统使用有向无环图来描述资源间的依赖关系，把它作为该系统的逻辑基础，总体结构分为维护层和工作层同，维护层存储管理监测元数据和控制工作层的运行，工作层依据维护层提供的元数据，负责实际的数据采集、处理、输出等与被监测动态数据直接相关的工作。工作层的监测代理实现为控制核心和扩展模块两部分，有利于实现功能动态扩展。还比较详细地介绍了系统各模块间的交互协议与通信优化。征收GMA相比，新系统更好地满足了网格监测的需求，以较低的系统开销获得较多的功能。     

基于移动代理技术的网格搜索服务的研究与实现

网格服务是网格的中心思想,但OGSA描述的网格服务是静止的,固定在能提供此服务的网格主机上,不具有移动性,由此带来了持续连接、带宽浪费、智能性不高、调用繁琐等缺点。本文在深入研究Globus网格和移动Agent技术后,将移动Agent应用于Globus网格服务的实现中,提出了基于此思想的网上信息搜索服务的模型及其原型系统的实现方法。这种网格服务具有灵活的可移动性,解决了静止服务产生的上述弊端。     

面向服务的电信宽带网格研究与设计

本文首先从网格技术的发展历程出发,阐述了网格技术从计算和数据网格向服务网格发展的重要趋势。由宽带业务发展产生的新需求展开分析,指明了新型的服务网格技术对于宽带业务模式革新具有重大的支撑作用。从我们的研究课题出发,提出了面向服务的电信宽带网格整体技术架构,然后主要阐述了该架构应用服务层和应用基础架构层两个层次的主要功能和实现机制,具体包括内容分发服务网格、多媒体在线游戏服务网格、宽带小区协同服务网格三个应用和资源,用户,安全,业务管理等基础服务机制。最后总结了服务网格给电信宽带业务模式转变带来的重大革新价值和未来的发展方向。