共查询到20条相似文献，搜索用时 15 毫秒
1.
Niels Drost Rob V. van Nieuwpoort Jason Maassen Frank J. Seinstra Henri E. Bal 《Concurrency and Computation》2011,23(13):1506-1521
The inherent complex nature of current distributed computing architectures hinders the widespread adoption of these systems for mainstream use. In general, users have access to a highly heterogeneous set of compute resources, which may include clusters, grids, desktop grids, clouds, and other compute platforms. This heterogeneity is especially problematic when running parallel and distributed applications. Software is needed which easily combines as many resources as possible into one coherent computing platform. In this paper, we introduce Zorilla: peer‐to‐peer (P2P) middleware that creates a single distributed environment from any available set of compute resources. Zorilla imposes minimal requirements on the resource used, is platform independent, and does not rely on central components. In addition to providing functionality on bare resources, Zorilla can exploit locally available middleware. Zorilla explicitly supports distributed and parallel applications, and allows resources from multiple sites to cooperate in a single computation. Zorilla makes extensive use of both virtualization and P2P techniques. We will demonstrate how virtualization and P2P combine into a simple design, while enhancing functionality and ease of use. Together, these techniques bring our goal a step closer: transparent, easy use of resources, even on very heterogeneous distributed systems. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
2.
Vincent Matossian Viraj Bhat Manish Parashar Ma&#x;gorzata Peszy&#x;ska Mrinal Sen Paul Stoffa Mary F. Wheeler 《Concurrency and Computation》2005,17(1):1-26
The emerging Grid infrastructure and its support for seamless and secure interactions is enabling a new generation of autonomic applications where the application components, Grid services, resources, and data interact as peers to manage, adapt and optimize themselves and the overall application. In this paper we describe the design, development and operation of a prototype of such an application that uses peer‐to‐peer interactions between distributed services and data on the Grid to enable the autonomic optimization of an oil reservoir. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
3.
The increasing popularity of multi‐player online games is leading to the widespread use of large‐scale Distributed Virtual Environments (DVEs) nowadays. In these systems, peer‐to‐peer (P2P) architectures have been proposed as an efficient and scalable solution for supporting massively multi‐player applications. However, the main challenge for P2P architectures consists of providing each avatar with updated information about which other avatars are its neighbors. This problem is known as the awareness problem. In this paper, we propose a comparative study of the performance provided by those awareness methods that are supposed to fully solve the awareness problem. This study is performed using well‐known performance metrics in distributed systems. Moreover, while the evaluations shown in the literature are performed by executing P2P simulations on a single (sequential) computer, this paper evaluates the performance of the considered methods on actually distributed systems. The evaluation results show that only a single method actually provides full awareness to avatars. This method also provides the best performance results. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
4.
This paper describes the issues that are involved in designing and implementing a large‐scale cooperative object database server for a collaborative virtual environment. The focus of the paper is about the way to handle the distributing factors and the communication model among nodes within a collaborative virtual environment. Within the system, all objects are decentralized and scattered among three tiers of object databases. By limiting the knowledge and refining the tasks for each server, the network and processor workload can be reduced. The objective of the system is to provide a virtual environment for distributed computing that is k‐fault tolerant and subject to expansion without the interruption of services. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
5.
As peer‐to‐peer (P2P) file‐sharing systems revolve around cooperation, the design of upload incentives has been one of the most important topics in P2P research for more than a decade. Several deployed systems, such as private BitTorrent communities, successfully manage to foster cooperation by banning peers when their sharing ratio becomes too low. Interestingly, recent measurements have shown that such systems tend to have an oversupply instead of an undersupply of bandwidth designers that have been obsessed with since the dawn of P2P. In such systems, the ‘selfish peer’ problem is finally solved, but a new problem has arisen: because peers have to keep up their sharing ratios, they now have to compete to upload. In this paper, we explore this new problem and show how even highly cooperative peers might in the end not survive the upload competition. On the basis of recent measurements of over half a million peers in private P2P communities, we propose and analyze several algorithms for uploader selection under oversupply. Our algorithms enable sustained sharing ratio enforcement and are easy to implement in both existing and new systems. Overall, we offer an important design consideration for the new generation of P2P systems in which selfishness is no longer an issue. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
6.
作为网格环境的基本服务,网格工作流的大规模共享和重用是使网格成为问题求解的智能化集成环境的一项核心技术。工作流复合技术能够通过已存在的解决方法的重用简化复杂的科学应用问题,而基于语义的工作流复合降低了需要了解工作流语法细节才能重用网格工作流带来的复杂性。首先运用知识表达技术提出一个基于目标概念的网格工作流语义模板,其次介绍了一个实现基于语义的工作流复合的工作流管理原型系统,其中详细阐述了工作流建模过程中基于语义的工作流复合的实现。 相似文献
7.
John A. Miller Devanand Palaniswami Amit P. Sheth Krys J. Kochut Harvinder Singh 《Journal of Intelligent Information Systems》1998,10(2):185-215
METEOR2 workflow management systems consist of both (1) design/build-time and (2) run-time/enactment components for implementing workflow applications. An enactment system provides the command, communication and control for the individual tasks in the workflow. Tasks are the run-time instances of intra- or inter-enterprise applications. We are developing three implementations of the METEOR2 model: WebWork, OrbWork and NeoWork. This paper discusses WebWork, an implementation relying solely on Web technology as the infrastructure for the enactment system. WebWork supports a distributed implementation with participation of multiple Web servers. It also supports automatic code generation of workflow applications from design specifications produced by a comprehensive graphical designer. WebWork has been developed as a complement of its more heavyweight counterparts (OrbWork and NeoWork), with the goal of providing ease of workflow application development, installation, use and maintenance. At the time of this writing, WebWork has been installed by several of the LSDIS Lab's industrial partners for testing, evaluation and building workflow applications. 相似文献
8.
To achieve high data availability or reliability in an efficient manner, distributed storage systems must detect whether an observed node failure is permanent or transient, and if necessary, generate replicas to restore the desired level of replication. Given the unpredictability of network dynamics, however, distinguishing permanent and transient failures is extremely difficult. Though timeout‐based detectors can be used to avoid mistaking transient failures as permanent failures, it is unknown how the timeout values should be selected to achieve a better tradeoff between detection latency and accuracy. In this paper, we address this fundamental tradeoff from several perspectives. First, we explore the impact of different timeout values on maintenance cost by examining the probability of their false positives and false negatives. Second, we propose a self‐configurable failure detector called the Neutralizer based on the idea of counteracting false positives with false negatives. The Neutralizer could enable the system to maintain a desired replication level on average with the least amount of bandwidth. We conduct extensive simulations using real trace data from a widely deployed peer‐to‐peer system and synthetic traces based on PlanetLab and Microsoft PCs, showing a significant reduction in aggregate bandwidth usage after applying the Neutralizer (especially in an environment with a low average node availability). Overall, we demonstrate that the Neutralizer closely approximates the performance of a perfect ‘oracle’ detector in many cases. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
9.
信息网格平台工作流程的实现 总被引：4，自引：0，他引：4
信息网格系统是利用网格技术实现信息资源的共享、管理和提供信息服务的系统。该文结合信息网格系统在企业信息共享研究和实施工作,分析了基于信息网格平台流程引擎的关键问题,提出了信息网格平台流程的体系结构,并讨论了实现细节,并就实际工程中的使用进行初步评价。 相似文献
10.
网格工作流模型和协同机制的研究与实现 总被引：2，自引：0，他引：2
网格技术为分布式的资源和服务共享提供了一个标准的平台,工作流在将网格资源和服务组合起来完成较复杂的业务流程具有独特的优势,协同机制保证了分布的组织／个人高效协作的完成工作。在对这三者充分研究的基础上提出了一个基于网格平台的协同工作流模型,探讨了在网格平台上服务、资源协同机制的应用,初步实现了可定制的协同的网格服务流程。 相似文献
11.
由于对等网络上的资源不是在一个单一的服务器上,而是分散在各个对等体上,理想状态下各个对等体是平等的,但它们在提供资源能力上又是各不相同的,因此,在进行查询搜索时,需要对这些对等体给予不同的优先级和处理方法。本文在分析对等网络中现有的搜索机制的基础上,提出了一种利用节点的分组和层次化来提高搜索的效率,增强系统的扩展性的搜索模型。 相似文献
12.
基于可信对等的分布式入侵检测通信框架设计 总被引：1，自引：0，他引：1
为了提高分布式入侵检测的实时性和安全性,提出了一种可信对等的分布式入侵检测通信框架的模型.该模型借鉴了P2P和代理技术,不同网络节点中的入侵检测代理是对等的,它们之间通过共享检测信息进行整体协防.该模型还借鉴了安全通信技术,在网络中建立了一个认证服务器,不在同一网络节点的任何两个网络进程的通信必须通过该认证服务器,提高了入侵检测自身的安全性.设计实现了一个原型系统,原型系统的实验结果表明了该模型的正确性和可行性. 相似文献
13.
MAGDA: A Mobile Agent based Grid Architecture 总被引：1，自引：0，他引：1
Rocco Aversa Beniamino Di Martino Nicola Mazzocca Salvatore Venticinque 《Journal of Grid Computing》2006,4(4):395-412
Mobile agents mean both a technology and a programming paradigm. They allow for a flexible approach which can alleviate a number of issues present in distributed and Grid-based systems, by means of features such as migration, cloning, messaging and other provided mechanisms. In this paper we describe an architecture (MAGDA – Mobile Agent based Grid Architecture) we have designed and we are currently developing to support programming and execution of mobile agent based application upon Grid systems. 相似文献
14.
分布式哈希表(distributed hash table, DHT)由于其高效的数据寻址方式而被广泛应用于分布式存储.传统DHT必须将数据存放在指定节点中才能实现高效的数据分布式寻址,极大地限制了DHT技术的应用范围.例如,在异构存储网络中,节点的存储空间、带宽、稳定性等均有较大差异,结合数据特征和节点性能差异选择合适的数据存放节点可以很大程度上提高数据的访问效率,而传统DHT数据和存储位置紧耦合的特征导致其难以应用于异构的存储网络中.针对此问题,提出了vRoute算法以实现DHT中数据标识与其存储位置的解耦.通过构建基于Bloom Filter的分布式数据索引, vRoute算法可以在不降低数据寻址效率的基础上允许数据存储在网络中的任意节点.通过扩展Kademlia算法实现了vRoute,并从理论上证明了vRoute算法的有有效性.最后,模拟实验表明vRoute以较低的存储、网络开销实现了和传统的DHT算法接近的数据寻址效率. 相似文献
15.
Marinho Pilla Barcellos Luciano Paschoal Gaspary Weverton Luis da Costa Cordeiro Rodolfo Stoffel Antunes 《Concurrency and Computation》2011,23(1):117-141
Despite being currently one of the main Internet applications, P2P file sharing has been hampered by content pollution attacks. To tackle this problem, we introduce a novel pollution control strategy that consists in adjusting the rate in which content is disseminated, according to content version reputation. The proposed strategy is modeled and evaluated using simplifying assumptions. Then, inspired by classic distributed designs, we propose a pollution control mechanism that implements such a strategy. The mechanism is evaluated in terms of the delays imposed on non‐polluted version dissemination, the effectiveness of reducing dissemination when the version is polluted, and the negative impact that collusion attacks can impose on the reputation system upon which our mechanism is built. Simulation results looking at scenarios with several hundred peers indicate that the pollution control mechanism can effectively reduce pollution without substantially affecting the dissemination of non‐polluted content. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
16.
17.
Techniques for Supporting Dynamic and Adaptive Workflow 总被引：30，自引：0，他引：30
Peter J. Kammer Gregory Alan Bolcer Richard N. Taylor Arthur S. Hitomi Mark Bergman 《Computer Supported Cooperative Work (CSCW)》2000,9(3-4):269-292
The unpredictability of business processes requires that workflowsystems support exception handling with the ability to dynamicallyadapt to the changing environment. Traditional approaches to handlingthis problem have fallen short, providing little support for change,particularly once the process has begun execution. Further,exceptions vary widely in their character and significance,challenging the application of any single approach to handling them.We briefly discuss the classification of exceptions, highlightingdiffering impacts on the workflow model. Based on this discussion, wesuggest principal goals to address in the development of adaptiveworkflow support, including strategies for avoiding exceptions,detecting them when they occur, and handling them at various levels ofimpact. We then identify a number of specific approaches to supportingthese goals within the design of a workflow system infrastructure.Finally, we describe the implementation of many of these approaches inthe Endeavors workflow support system. 相似文献
18.
A peer‐to‐peer (P2P) characterization model is proposed in this paper. The purposes of this model are (a) to describe through abstraction the behavior and capability of P2P computing independent of any specific application, and (b) to lead to a cost model of P2P computing. Our approach is based on abstracting the service driven nature of P2P computing separate and distinct from its implementation. This supports the first purpose. Next, we consider the integration of the two aspects. This supports the second purpose. A secondary contribution of our work is a cost model. The cost model is applied to indexing, discovery and resource utilization services. In addition, the characterization model and cost model are applied to a JXTA‐based P2P application. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
19.
P2P(peer to peer)网络中,节点的自私行为极大地降低了系统的可用性.基于债务关系的文件交换网络,构建了一种促进合作的激励机制.同时,该机制保证了文件交换的公平性.激励机制的关键在于DHT(distributed hash table)网络邻居有限的固有特征,因而节点间的交互易于形成重复博弈.DFFE(debt relationship based fair file exchange in DHT network)协议只需维护很少的本地节点交互信息,协议开销小、网络扩展性好.网络路由采用基于一跳信息的贪婪算法.理性节点间的博弈存在纳什均衡,其策略选择的近似算法具有渐进收敛性.仿真实验表明了激励机制的有效性和在动态网络中性能的稳定性. 相似文献
20.
Timely and efficient information communication is a key factor in ensuring successful collaboration in engineering collaborative design. This work proposes a database approach to support information communication between distributed and autonomous CAD systems. It provides the designer with an easy and flexible way, a project‐based propagation meta‐table, to specify what parts of a CAD information model should be communicated to other collaborating designers. A CAD peer manager, containing a peer database that stores information to be exchanged with the other collaborators, wraps each participating CAD system. The peer manager identifies changes made to the CAD model by using stored procedures and active rules in the peer database that are automatically generated based on the propagation meta‐table. The identified updates are propagated in a timely manner to other peers via inter‐database message passing, thereby minimizing the volume of necessary information to be exchanged. Furthermore, remote peer designers can flexibly incorporate, filter, or delete received updates by using a propagation control interface, which is also used to issue user's commands to download the data from the CAD system to the peer database and lookup the received messages in the peer database. The approach is applicable on any CAD system having a CORBA interface and can also be applied to other kinds of object‐oriented interfaces. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献