基于Web Services的网格计算中间件研究

随着网格计算技术的发展和Web Services技术的出现,使得整合各种计算资源解决具有重大挑战性的科学和工程计算问题成为可能.在对已有的应用于高性能计算的网格计算系统Netsolve进行研究的基础上,结合Web Services技术提出了一种用于高性能计算的网格系统,并且在初步实现的基础上,探讨了系统的优缺点.     

VCluster: a thread‐based Java middleware for SMP and heterogeneous clusters with thread migration support

Clusters, composed of symmetric multiprocessor (SMP) machines and heterogeneous machines, have become increasingly popular for high‐performance computing. Message‐passing libraries, such as message‐passing interface (MPI) and parallel virtual machine (PVM), are de facto parallel programming libraries for clusters that usually consist of homogeneous and uni‐processor machines. For SMP machines, MPI is combined with multithreading libraries like POSIX Thread and OpenMP to take advantage of the architecture. In addition to existing parallel programming libraries that are in C/C++ and FORTRAN programming languages, the Java programming language presents itself as another alternative with its object‐oriented framework, platform neutral byte code, and ever‐increasing performance. This paper presents a new parallel programming model and a library, VCluster, which implements this model. VCluster is based on migrating virtual threads instead of processes to support clusters of SMP machines more efficiently. The implementation uses thread migration, which can be used in dynamic load balancing. VCluster was developed in pure Java, utilizing the portability of Java to support clusters of heterogeneous machines. Several applications are developed to illustrate the use of this library and compare the usability and performance of VCluster with other approaches. Copyright © 2007 John Wiley & Sons, Ltd.     

Babylon: middleware for distributed,parallel, and mobile Java applications

Babylon is a collection of tools and services that provide a 100% Java‐compatible environment for developing, running and managing parallel, distributed and mobile Java applications. It incorporates features such as object migration, asynchronous method invocation, and remote class loading, while providing an easy‐to‐use interface. Additionally, Babylon enables Java applications to seamlessly create and interact with remote objects, while protecting those objects from other applications by implementing access restrictions and separate namespaces. The implementation of Babylon centers around dynamic proxies, a feature first available in Java 1.3, that allow proxy objects to be created at runtime. Dynamic proxies play a key role in achieving the goals of Babylon. The potential cluster computing benefits of the system are demonstrated with experimental results, which show that sequential Java applications can achieve significant performance benefits from using Babylon to parallelize their work across a cluster of workstations. Copyright © 2008 John Wiley & Sons, Ltd.     

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.     

基于Java实现移动Agent强迁移的方法

对比分析了常见的移动Agent强迁移与弱迁移,提出一种基于Java实现移动Agent强迁移的方法.该方法基于IBMJikesRvm(Jikes research virtual machine(RVM))提供的RVM,利用OSR(on-stack replacement)捕捉运行堆栈的状态,实现了移动Agent强迁移.该方法不需要对源代码或字节码进行预处理,也不需要改变JVNI,具有很好的系统扩展性.     

Java线程迁移机制的研究

从计算机集群系统实际应用出发,首先对Java线程的状态进行了分析,介绍了目前Java线程迁移机制的几种实现方法：处理源代码、处理字节码和扩展Java虚拟机的实现机制.从3个不同的方面进行了性能分析和比较,得出一个初步的评估.最后提出了一种扩展Java虚拟机方法的改进以及该迁移技术在集群系统中的应用.     

Klava: a Java package for distributed and mobile applications

Highly distributed networks have now become a common infrastructure for wide‐area distributed applications whose key design principle is network awareness, namely the ability to deal with dynamic changes of the network environment. Network‐aware computing has called for new programming languages that exploit the mobility paradigm as a basic interaction mechanism. In this paper we present the architecture of KLAVA , an experimental Java package for distributed applications and code mobility. We describe how KLAVA permits code mobility by relying on Java and present a few distributed applications that exploit mobile code programmed in KLAVA . Copyright © 2002 John Wiley & Sons, Ltd.     

Grids and Grid technologies for wide‐area distributed computing

The last decade has seen a substantial increase in commodity computer and network performance, mainly as a result of faster hardware and more sophisticated software. Nevertheless, there are still problems, in the fields of science, engineering, and business, which cannot be effectively dealt with using the current generation of supercomputers. In fact, due to their size and complexity, these problems are often very numerically and/or data intensive and consequently require a variety ofheterogeneous resources that are not available on a single machine. A number of teams have conducted experimental studies on the cooperative use of geographically distributed resources unified to act as a single powerful computer. This new approach is known by several names, such as metacomputing, scalable computing, global computing, Internet computing, and more recently peer‐to‐peer or Grid computing. The early efforts in Grid computing started as a project to link supercomputing sites, but have now grown far beyond their original intent. In fact, many applications can benefit from the Grid infrastructure, including collaborative engineering, data exploration, high‐throughput computing, and of course distributed supercomputing. Moreover, due to the rapid growth of the Internet and Web, there has been a rising interest in Web‐based distributed computing, and many projects have been started and aim to exploit the Web as an infrastructure for running coarse‐grained distributed and parallel applications. In this context, the Web has the capability to be a platform for parallel and collaborative work as well as a key technology to create a pervasive and ubiquitous Grid‐based infrastructure. This paper aims to present the state‐of‐the‐art of Grid computing and attempts to survey the major international efforts in developing this emerging technology. Copyright © 2002 John Wiley & Sons, Ltd.     

P2P-MPI: A Peer-to-Peer Framework for Robust Execution of Message Passing Parallel Programs on Grids

This paper presents P2P-MPI, a middleware aimed at computational Grids. From the programmer point of view, P2P-MPI provides a message-passing programming model which enables the development of MPI applications for Grids. Its originality lies in its adaptation to unstable environments. First, the peer-to-peer design of P2P-MPI allows for a dynamic discovery of collaborating resources. Second, it gives the user the possibility to adjust the robustness of an execution thanks to an internal process replication mechanism. Finally, we measure the performance of the integrated message passing library on several benchmarks and on different hardware platforms.     

基于Web服务的电子商务业务流程中间件引擎的研究

从数个企业提供的逻辑相关的Web服务整合为可运行的电子商务业务流程的角度出发,分析Web服务的业务流程协议模型BPEIAWS(Business Process Execution Languagefor Web Service,Web服务的业务流程执行语言),在此基础上设计业务流程的中间件引擎以方便企业之间的业务集成并管理、执行、监控生成的业务流程实例,设计的同时充分考虑引擎的可扩充性,以利于引擎功能的完善和智能扩展。     

A distributed implementation of a virtual machine for Java

The cluster virtual machine (VM) for Java provides a single system image of a traditional Java Virtual Machine (JVM) while executing in a distributed fashion on the nodes of a cluster. The cluster VM for Java virtualizes the cluster, supporting any pure Java application without requiring that application be tailored specifically for it. The aim of our cluster VM is to obtain improved scalability for a class of Java Server Applications by distributing the application's work among the cluster's computing resources. The implementation of the cluster VM for Java is based on a novel object model which distinguishes between an application's view of an object (e.g. every object is a unique data structure) and its implementation (e.g. objects may have consistent replications on different nodes). This enables us to exploit knowledge on the use of individual objects to improve performance (e.g. using object replications to increase locality of access to objects). We have already completed a prototype that runs pure Java applications on a cluster of NT workstations connected by a Myrinet fast switch. The prototype provides a single system image to applications, distributing the application's threads and objects over the cluster. We used the cluster VM to run, without change, a real Java Server Application containing over 10 Kloc

1 Kloc means Kilo lines of code—used to describe the size of applications in terms of source lines count.

for the source code and achieved high scalability for it on a cluster. We also achieved linear speedup for another application with a large number of independent threads. This paper discusses the architecture and implementation of the cluster VM. It focuses on achieving a single system image for a traditional JVM on a cluster while describing, in short, how we aim to obtain scalability. Copyright © 2001 John Wiley & Sons, Ltd.     

基于JCF中间件的负载预测与过载迁移的融合算法

针对多种负载预测方法的适用场景进行了研究,提出了一种负载预测与过载迁移的融合算法。该算法提前对周期内无法提取到的负载情况进行预测且对超过负载阈值的服务器进行告警,关闭该进程将服务请求分发给轻负载服务器。通过提前预测与负载迁移的有机结合,解决了一个周期内无法获取各个节点的实际负载的问题,负载预测不准确的问题,以及可能出现的部分服务器过载、甚至崩溃的问题,最终达到了系统的负载均衡。在JCF（Java Component Framework）中间件平台上的实验结果表明本文算法优于静态加权轮询算法和动态加权轮询算法,在提高均衡效率、增加集群系统的吞吐量、降低服务请求响应时间多方面有着显著效果,在实际应用中有较大的价值。     

网格环境中基于Web服务的DAI中间件的设计与实现

分析和研究了网格环境中数据访问和集成(data access and integration,DAI)需求,结合中间件技术的特点,提出了具有N层应用体系结构的DAI中间件实现策略,即在不同种类的数据资源和网格应用之间构建了一个中间层软件--"虚拟数据库系统",经授权认证的合法用户可通过"虚拟数据库系统"提供的标准访问接口及统一数据格式对网格环境中各种分布的、异构的、不同种类的数据资源进行动态访问和集成.     

Design and implementation of S-MARKS: A secure middleware for pervasive computing applications

As portable devices have become a part of our everyday life, more people are unknowingly participating in a pervasive computing environment. People engage with not a single device for a specific purpose but many devices interacting with each other in the course of ordinary activity. With such prevalence of pervasive technology, the interaction between portable devices needs to be continuous and imperceptible to device users. Pervasive computing requires a small, scalable and robust network which relies heavily on the middleware to resolve communication and security issues. In this paper, we present the design and implementation of S-MARKS which incorporates device validation, resource discovery and a privacy module.     

基于SOA应用JMX和JMS技术的RFID中间件设计

针对企业级的需求,提出了一种基于SOA技术及JMX和JMS的RFID中间件架构,介绍了基础架构的设备管理层、事件处理层和服务接口层的具体实现。实验证明,该架构达到了设计要求。     

一种分布式环境中的二分式多层网格skyline算法

skyline计算在数据挖掘、多标准决策和数据库可视化等领域有着非常重要的作用,这些年已经得到了广泛的关注,以往对于skyline查询的研究大多集中在处理集中的数据集上,即集中式skyline查询,已经得到了很多的研究成果。然而,实际情况是：相关数据几乎分散在几个不同的服务器上,因此在分布式环境中的skyline查询计算需要从各个服务器收集大量的数据;现有的在分布式环境中的skyline查询方法有两个主要问题：一是skyline查询的处理时间较慢;二是在网络中服务器之间传输了很多不必要的重叠数据。提出了一种二分式多层网格法（DMLG）,可以有效地处理在分布式环境中的skyline查询。该方法利用网格的方法,借鉴二分法,最大限度地减少了不必要的重叠数据传输,基于不同的数据集的实验表明,这种方法优于现有的方法。     

Mobile JikesRVM: A framework to support transparent Java thread migration

Today’s complex applications must face the distribution of data and code among different network nodes. Computation in distributed contexts is demanding increasingly powerful languages and execution environments, able to provide programmers with appropriate abstractions and tools. Java is a wide-spread language that allows developers to build complex software, even distributed, but it cannot handle the migration of computations (i.e. threads), due to intrinsic limitations of many traditional JVMs. After analyzing the approaches in the literature, this paper presents our thread migration framework (called Mobile JikesRVM), implemented on top of the IBM Jikes Research Virtual Machine (RVM): exploiting some of the innovative techniques in the JikesRVM, we implemented an extension of its scheduler that allows applications to easily capture the state of a running thread and makes it possible to restore it elsewhere (i.e. on a different hardware architecture or operating system), but still with a version of the framework installed). Our thread serialization mechanism provides support for both proactive and reactive migration, available also for multi-threaded Java applications, and tools to deal with the problems of resource relocation management. With respect to previous approaches, we implemented Mobile JikesRVM without recompiling its JVM (Java Virtual Machine) source code, but simply extending JikesRVM functionalities with a full Java package to be imported when thread migration is needed.     

具有自主计算特征的新型网格体系结构研究

网格环境的复杂性和动态性迫切需要自主计算范型的支持。提出了一种具有自主计算特征的新型网格体系结构。网格的自我管理功能通过自主网格服务层、多Agent自主协同层和表达用户需求的政策层来完成。为了更好的实现Agent间的自主协同,提出了构造多Agent相似-关联树的算法。模拟环境下实现的网格原型系统的运行表明,符合该体系结构的网格系统具有一定程度的自配置、自优化、自保护和自愈合的能力。     

Data collection and restoration for heterogeneous process migration

This study presents a practical solution for data collection and restoration to migrate a process written in high‐level stack‐based languages such as C and Fortran over a network of heterogeneous computers. We first introduce a logical data model, namely the Memory Space Representation (MSR) model, to recognize complex data structures in process address space. Then, novel methods are developed to incorporate the MSR model into a process, and to collect and restore data efficiently. We have implemented prototype software and performed experiments on different programs. Experimental and analytical results show that: (1) a user‐level process can be migrated across different computing platforms; (2) semantic information of data structures in the process's memory space can be correctly collected and restored; (3) costs of data collection and restoration depend on the complexity of the MSR graph in the memory space and the amount of data involved; and (4) the implantation of the MSR model into the process is not a decisive factor of incurring execution overheads. With appropriate program analysis, we can practically achieve low overhead. Copyright © 2002 John Wiley & Sons, Ltd.