Explore the vast range of titles available.

Although many scientific applications rely on data stored in databases, most workflow management systems are not capable of establishing database connections during workflow execution. For this reason, e-Scientists have to use different tools before workflow submission to access their datasets and gather the required data on which they want to carry out computational experiments. Open Grid Services Architecture Data Access and Integration (OGSA-DAI) is a good candidate to use as middleware providing access to several structured and semi-structured database products through Web/Grid services. The integration technique and its reference implementation described in this paper enable e-Scientists to reach databases via OGSA-DAI within their scientific workflows at run-time and give a general solution that can be adopted by any workflow management system.

Computational steering refers to the real-time interaction of a scientist with their running simulation code. Despite the many benefits associated with computational steering, its uptake to date has been limited. In this paper we discuss the reasons for this and how the computational steering library and associated tools developed as part of the RealityGrid project aim to tackle them. We describe the functionality of the steering library and the use of Grid services in constructing a generic, dynamic architecture for discovering, steering and connecting visualization software to running simulations. The use of on-line visualization for providing feedback to the scientist is described, including the ways in which it may be enhanced through tools such as Chromium and Access Grid. Finally, we illustrate the flexibility of our approach by describing the functionality that has been added to various simulation codes as part of the RealityGrid project.

Grid is an emerging infrastructure which enables effective coordinate access to various distributed computing resources in order to serve the needs of collaborative research and work across the world. Grid resource management is always a key subject in the grid computing. We first analyze the resource management in the grid computing environment, then according to the load imbalance question in the ant colony optimization algorithm, propose an improved algorithm that suits to be used in the grid environment.

In this paper, we propose a role-based access control (RBAC) method for grid database services in open grid services architecture-data access and integration (OGSA-DAI). OGSA-DAI is an efficient grid-enabled middleware implementation of interfaces and services to access and control data sources and sinks. However, in OGSA-DAI, access control causes substantial administration overhead for resource providers in virtual organizations (VOs) because each of them has to manage a role-map file containing authorization information for individual grid users. To solve this problem, we used the community authorization service (CAS) provided by the globus toolkit to support the RBAC within the OGSA-DAI framework. The CAS grants the membership on VO roles to users. The resource providers then need to maintain only the mapping information from VO roles to local database roles in the role-map files, so that the number of entries in the role-map file is reduced dramatically. Furthermore, the resource providers control the granting of access privileges to the local roles. Thus, our access control method provides increased manageability for a large number of users and reduces day-to-day administration tasks of the resource providers, while they maintain the ultimate authority over their resources. Performance analysis shows that our method adds very little overhead to the existing security infrastructure of OGSA-DAI

From the perspective of resource sharing, grid computing is a system ranging from small kind of network system for home using to large-scale network computing systems even to the Internet. The management of resources in the grid environment becomes very complex as these resources are distributed geographically, heterogeneous in nature, and each having their own resource management policies and different access as well as cost models. In this paper, we bring forward an efficient resources management model and task scheduling algorithm in grid computing. The simulation results show that the proposed algorithm achieves resource load balancing, and can be applied to the optimization of task scheduling successfully.

Grid computing is a new type of network computing platform emerged after the World Wide Web, which objective is to provide a kind of infrastructure that shares all kinds of information for user． This paper brings forward a Grid-P2P model based on Peer-to-Peer computing, and designs a peer-to-peer genetic scheduling algorithm. The simulation results show that this model increased validity and accuracy of grid computing. It can be applied to the optimization of task scheduling successfully.

In this paper, we present a role-based access control method for accessing databases through the Open Grid Services Architecture – Data Access and Integration (OGSA-DAI) framework. OGSA-DAI is an efficient Grid-enabled middleware implementation of interfaces and services to access and control data sources and sinks. However, in OGSA-DAI, access control causes substantial administration overhead for resource providers in virtual organizations (VOs) because each of them has to manage a role-map file containing authorization information for individual Grid users. To solve this problem, we used the Community Authorization Service (CAS) provided by the Globus Toolkit to support the role-based access control (RBAC) within OGSA-DAI. CAS uses the Security Assertion Markup Language (SAML). Our method shows that CAS can support a wide range of security policies using role-privileges, role hierarchies, and constraints. The resource providers need to maintain only the mapping information from VO roles to local database roles and the local policies in the role-map files, so that the number of entries in the role-map file is reduced dramatically. Also, unnecessary authentication, mapping and connections can be avoided by denying invalid requests at the VO level. Thus, our access control method provides increased manageability for a large number of users and reduces day-to-day administration tasks of the resource providers, while they maintain the ultimate authority over their resources. Performance analysis shows that our method adds very little overhead to the existing security infrastructure of OGSA-DAI.

Service Oriented Architectures (SOAs) support service lifecycle tasks, including Development, Deployment, Discovery and Use. We observe that there are two disparate ways to use Grid SOAs such as the Open Grid Services Architecture (OGSA) as exemplified in the Globus Toolkit (GT3/4). One is a traditional enterprise SOA use where end-user services are developed, deployed and resourced behind firewalls, for use by external consumers: a service-centric (or ‘first-order’) approach. The other supports end-user development, deployment, and resourcing of applications across organizations via the use of execution and resource management services: A Resource-centric (or ‘second-order’) approach. We analyze and compare the two approaches using a combination of empirical experiments and an architectural evaluation methodology (scenario, mechanism, and quality attributes) to reveal common and distinct strengths and weaknesses. The impact of potential improvements (which are likely to be manifested by GT4) is estimated, and opportunities for alternative architectures and technologies explored. We conclude by investigating if the two approaches can be converged or combined, and if they are compatible on shared resources.

NAREGI is a 5-year Japanese National Grid Project during 2003–2007, whose chief aim is to develop a set of grid middleware to serve as a basis for future e-Science. NAREGI also aims to lead the way in standardization of grid middleware, based on the OGSA architecture. Its super-scheduler is based on the proposed OGSA-EMS Architecture, in that it becomes the first working implementation that implements the documented component relationships within the OGSA-EMS architecture document v.1.0. Through the efforts and experience in the design and implementation, it has been confirmed that the documented OGSA-EMS architecture is quite feasible, but will require significant amount of refinement and speed improvements to finalize its detailed specifications. The super-scheduler also supports co-allocation across multiple sites to support automated execution of grid-based MPIs that execute across machines. Such a resource allocation requires sophisticated interactions between the OGSA-EMS components not covered in the current OGSA-EMS architecture, some of which are non-trivial. Overall, job scheduling with OGSA-EMS has proven to not only work, but also that its job allocation and execution time is within reasonable bounds.

Chapter 1 is an introduction to the topic. It covers “What Is Grid Computing And What Are The Key Issues?” It also looks at potential applications and financial benefits of Grid Computing. The chapter also looks at grid types, topologies, components, standards, and layers. A comparison with other approaches is provided. The adoption of the Web Services (WS) model for Grid Computing is discussed.