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ABSTRACT: In the first article of this series, we identified the need for teaching environments that provide infrastructure to support education and training in distributed computing. Training infrastructure, or t-infrastructure, is analogous to the teaching laboratory in biology and is a vital tool for educators and students. In practice, t- infrastructure includes the computing equipment, digital communications, software, data, and support staff necessary to teach a course. The International Summer Schools in Grid Computing (ISSGC) series and the first International Winter School on Grid Computing (IWSGC 08) used the Grid INFN Laboratory of Dissemination Activities (GILDA) infrastructure so students could gain hands-on experience with middleware. Here, we describe GILDA, related summer and winter school experiences, multimiddleware integration, t-infrastructure, and academic courses, concluding with an analysis and recommendations.
IEEE Distributed Systems Online 11/2008;
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ABSTRACT: Since the birth of computational and data grids, many middlewares have been developed and deployed. Currently, they are used in a multitude of isolated e-infrastructures and a hot topic in grid technology in the last year or so has been that of middleware interoperability/interoperation. In this paper we present a new approach to grid interoperation based on the so called middleware co-existence. Following this approach, different middlewares are deployed on the same infrastructure and allow the same users to access and/or share the resources, with well defined policy, regardless the middleware they want to use. Although this approach has been used for educational purposes in a training infrastructure, it is so general that it could be used everywhere the interoperation is a concern for the users and/or site managers of an e-infrastructure.
e-Science and Grid Computing, IEEE International Conference on; 01/2008
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ABSTRACT: Huge amount of data can be stored on Grid Storage Elements, but few tools are provided by the EGEE gLite middleware to easily search and retrieve files a user is looking for. File catalogues can help organizing data in hierarchical structures, but they do not provide a way to describe file contents. On the other hand, we have Metadata Services, that can be used to attach additional information to files, but this services are not so easy to use by non-experienced people. In this paper a easy-to-use system to handle digital assets stored as grid file is presented. Such system is called gLibrary. It offers a intuitive interface that allow users to browse and filter the available entries, as well as to retrieve or upload a file by copying it from one of the Storage Elements (SEs) into user's local machine, or vice-versa.
Enabling Technologies: Infrastructure for Collaborative Enterprises, 2007. WETICE 2007. 16th IEEE International Workshops on; 07/2007
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ABSTRACT: Grid computing empowers users to employ a huge amount of resources to perform their task. Many services allows to access these resources with different methods and supporting different QoS. In order to use the services an agreement between the user and the provider has to be defined, where users specify the QoS required from the service to perform their activities correctly and, at the same time, providers declare the QoS offered with the service. Current solutions to reach an agreement between users and providers do not consider many aspects related to the use or misuse of services that can seriously influence or even nullify the agreement itself. This paper presents a simple formalism to define more rigourously an agreement, and a discussion about several problems related to the introduction of agreements. Actually, at the time when an agreement is signed many information are unknown from users and providers, therefore they take a risk to sign an agreement which can sometimes be wrong. Moreover, if problems arise during the execution, users and providers cannot decide who is responsible for the problem and eventually refund the other.
Enabling Technologies: Infrastructure for Collaborative Enterprises, 2007. WETICE 2007. 16th IEEE International Workshops on; 07/2007
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ABSTRACT: The grid is a dynamic environment in which resources can quickly go from idle to busy state depending on application operations. In such a scenario, resources can be used more effectively by introducing reservation and allocation. As a solution, this paper proposes STREGA: a software architecture that handles resource reservation and greatly simplifies the integration of applications with a grid environment. In it, resources needed by applications are automatically detected, and operations such as resource reservation and allocation are accordingly transparently performed, e.g. using Globus services. Within STREGA, some components are aimed at understanding the needs of application classes, other components dynamically re-adapt resource requests on the basis of the observed application behaviour. Additional components are proposed to support reservation when this is unavailable from the underlying system (i.e. Globus and the OS).
Enabling Technologies: Infrastructure for Collaborative Enterprises, 2004. WET ICE 2004. 13th IEEE International Workshops on; 07/2004
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ABSTRACT: This paper discusses an approach to evaluating the separa-tion of concerns for an object-oriented software system. For assessing this separation, the developer is asked to specify the nature of classes through annotations. Automatic identi-fication of some structural characteristics (e.g., inheritance, libraries, synchronisation) is used to appraise the composi-tion and intertwining of concerns inside a class.
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ABSTRACT: Science Gateways are playing an important role in scientific research performed using e-Infrastructures and their relevance will further increase with the development of more sophisticated user interfaces and easier access mechanism. Through the highly collaborative environment of a Science Gateway, users spread around the world and belonging to various Virtual Research Communities can easily cooperate to reach common goals and exploit all the resources of the cyber-infrastructure they are entitled to use. One of the major tasks of a Science Gateway is to supervise the user access to the available services, denying the use to those people who are not authorised. This activity has to comply with the role of users inside the VRC. Users operating in a Science Gateway can belong to different organisations having their own security policies and the Virtual Research Community has to comply with them. As a result, the security chain inside the Science Gateway has to allow each organisation to keep the control of their users hiding, at the same time, the complexity of the security mechanisms underneath the portal. In this work we present a general framework to build Science Gateways [1][2] and the customisations made to meet the requirements of a couple of use cases coming from different scientific communities: those of the European Union funded DECIDE (www.eu-decide.eu) and INDICATE (www.indicate-project.eu) projects. The goal of DECIDE project is to design, implement, and validate a Science Gateway for the computer-aided extraction of diagnostic markers from medical images for the early diagnosis of Alzheimer Disease and other forms of dementia. Using the same platform neurologists, physicians and scientists can store their images and data on grid and perform analysis and comparisons with a huge set of reference cases available on grid. The INDICATE project aims instead at demonstrating, with real-life examples, the advantages of the adoption of e-Infrastructures in the digital cultural heritage domain. The plugin developed enables INDICATE Science Gateway, and its digital cultural heritage community, to access two different e-Infrastructure repositories in an easy way with a friendly user interface but keeping the digital resources safe and the transactions private. The framework defined to support the above use cases is an extension of Liferay portal framework, which provides a whole set of web 2.0 tools and services for the development of generic portals. These have been integrated with a more flexible security workflow and a new set of portlets to access the Grid services. The final architecture of a Science Gateway consists of two part: a front-end building the graphical user interface, and a back-end providing the access to the grid services implemented. A major extension to Liferay is the security system. The new developed security system merges three different security mechanisms in a single workflow allowing users to access Grid resources based on the credentials provided by the organisations they belong to. The idea behind was to combine Shibboleth2 identities in the front-end with X.509 proxies generated by robot certificates in the back-end. The former enables the federation of organisations having different authentication policies while the latter allows users to access Grid resources, without needing any personal certificates whose request and management procedure is very often judged quite cumbersome by non-experts. The "glue" between the two layers is an LDAP server running in the back-end that implements a mechanism to map authorised users on Grid resources. Services managing user and grid credentials are not integrated in Liferay Portal but run in different hosts, in order to increase the reliability and security of the Science Gateway. Once the user is authenticated, the portlets developed provide the functionalities to manage the Grid credentials in order to access the e-Infrastructure behind. The portlet-based interface to Grid is built on the OGF-standard SAGA Java API and it is not bound to any particular middleware. Besides the interaction with the computational services of an e-Infrastructure, the proposed framework includes the possibility to easily build and manage data repositories interacting with the gLibrary framework [3] and to encrypt/decrypt sensible data with the Secure Storage System [4].
