In both e-business and e-science, we often need to integrate services across distributed, heterogeneous, dynamic “virtual organizations ” formed from the disparate resources within a single enterprise and/or from external resource sharing and service provider relationships. This integration can be technically challenging because of the need to achieve various qualities of service when running on top of different native platforms. We present an Open Grid Services Architecture that addresses these challenges. Building on concepts and technologies from the Grid and Web services communities, this architecture defines a uniform exposed service semantics (the Grid service); defines standard mechanisms for creating, naming, and discovering transient Grid service instances; provides location transparency and multiple protocol bindings for service instances; and supports integration with underlying native platform facilities. The Open Grid Services Architecture also defines, in terms of Web Services Description Language (WSDL) interfaces and associated conventions, mechanisms required for creating and composing sophisticated distributed systems, including lifetime management, change management, and notification. Service bindings can support reliable invocation, authentication, authorization, and delegation, if required. Our presentation complements an earlier foundational article, “The Anatomy of the Grid, ” by describing how Grid mechanisms can implement a service-oriented architecture, explaining how Grid functionality can be incorporated into a Web services framework, and illustrating how our architecture can be applied within commercial computing as a basis for distributed system integration—within and across organizational domains. This is a DRAFT document and continues to be revised. The latest version can be found at

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An important class of networked systems is emerging that involve very large numbers of small, low-power, wireless devices. These systems offer the ability to sense the environment densely, offering unprecedented opportunities for many scientific disciplines to obtain detailed datasets for analysis. In this paper, we argue that a data handling architecture for these devices should incorporate their extreme resource constraints - energy, storage and processing - and spatiotemporal interpretation of the physical world in the design, cost model, and metrics of evaluation. We describe DIMENSIONS, a system that provides a unified view of data handling in sensor networks, incorporating long-term storage, multiresolution data access and spatio-temporal pattern mining.

The Grid and agent communities both develop concepts and mechanisms for open distributed systems, albeit from different perspectives. The Grid community has historically focused on "brawn": infrastructure, tools, and applications for reliable and secure resource sharing within dynamic and geographically distributed virtual organizations. In contrast, the agents community has focused on "brain": autonomous problem solvers that can act flexibly in uncertain and dynamic environments. Yet as the scale and ambition of both Grid and agent deployments increase, we see a convergence of interests, with agent systems requiring robust infrastructure and Grid systems requiring autonomous, flexible behaviors. Motivated by this convergence of interests, we review the current state of the art in both areas, review the challenges that concern the two communities, and propose research and technology development activities that can allow for mutually supportive efforts.

Grid computing is becoming a mainstream technology for large-scale distributed resource sharing and system integration. Workflow management is emerging as one of the most important grid services. In this work, a workflow management system for grid computing, called GridFlow, is presented, including a user portal and services of both global grid workflow management and local grid sub-workflow scheduling. Simulation, execution and monitoring functionalities are provided at the global grid level, which work on top of an existing agent-based grid resource management system. At each local grid, sub-workflow scheduling and conflict management are processed on top of an existing performance prediction based task scheduling system. A fuzzy timing technique is applied to address new challenges of workflow management in a cross-domain and highly dynamic grid environment. A case study is given and corresponding results indicate that local and global grid workflow management can coordinate with each other to optimise workflow execution time and solve conflicts of interest. 1.

Grids aim at exploiting synergies that result from cooperation of autonomous distributed entities. The synergies that result from grid cooperation include the sharing, exchange, selection, and aggregation of geographically distributed resources such as computers, data bases, software, and scientific instruments for solving large-scale problems in science, engineering, and commerce. For this cooperation to be sustainable, participants need to have economic incentive. Therefore, "incentive" mechanisms should be considered as one of key design parameters of Grid architectures. In this article, we present an overview and status of an open source Grid toolkit, called Gridbus, whose architecture is fundamentally driven by the requirements of Grid economy. Gridbus technologies provide services for both computational and data grids that power the emerging eScience and eBusiness applications.

JBoss is an extensible, reflective, and dynamically reconfigurable Java application server. It includes a set of components that implement the J2EE specification, but its scope goes well beyond J2EE. JBoss is open-ended middleware, in the sense that users can extend middleware services by dynamically deploying new components into a running server. We believe that no other application server currently offers such a degree of extensibility. This paper focuses on two major architectural parts of JBoss: its middleware component model, based on the JMX model, and its meta-level architecture for generalized EJBs. The former requires a novel class loading model, which JBoss implements. The latter includes a powerful and flexible remote method invocation model, based on dynamic proxies, and relies on systematic usage of interceptors as aspect-oriented programming artifacts.

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Divisible load applications occur in many fields of science and engineering, can be eas-ily parallelized in a master-worker fashion, but pose several scheduling challenges. While a number of approaches have been proposed that allocate work to workers in a single round, using multiple rounds improves overlap of computation with communication. Unfortunately, multi-round algorithms are difficult to analyze and have thus received only limited attention. In this paper we answer three open questions in the multi-round divisible load scheduling area: (i) How to account for latencies? (ii) How to account for heterogeneous platforms; and (iii) How many rounds should be used? To answer (i), we derive the first closed-form optimal schedule for a homogeneous platform with both computation and communication latencies, for a given number of rounds. To answer (ii) and (iii), we present a novel algorithm, UMR. We use simulation to evaluate UMR in a variety of realistic scenarios.

The MyProxy online credential repository has been used by the grid computing community for over four years for managing security credentials in the grid public key infrastructure. MyProxy improves usability by giving users access to their credentials over the network using password authentication, allowing users to delegate their credentials via web browser interfaces to the grid, and supporting credential renewal for long-running jobs. MyProxy helps administrators secure users ’ private keys by providing an online service from which users retrieve short-lived credentials without distributing long-lived keys to potentially vulnerable end-systems. This paper describes the MyProxy system and its use. key words: grid computing, credential management, public key infrastructure, virtual smart card