Remote Computational Resources Research Articles

Innovations of the NetSolve Grid Computing System

AbstractThe NetSolve Grid Computing System was first developed in the mid 1990s to provide users with seamless access to remote computational hardware and software resources. Since then, the system has benefitted from many enhancements like security services, data management faculties and distributed storage infrastructures. This article is meant to provide the reader with details regarding the present state of the project, describing the current architecture of the system, its latest innovations and other systems that make use of the NetSolve infrastructure. Copyright © 2002 John Wiley & Sons, Ltd.

Mississippi Computational Web Portal

AbstractThis paper describes design and implementation of an open, extensible object‐oriented framework that allows the integration of new and legacy components into a single user‐friendly Grid computing environment. Thus we extend the researcher's desktop by providing seamless access to remote resources (that is, hardware, software, and data), and thereby simplifying currently difficult to comprehend and changing interfaces and emerging protocols. The user, through the familiar Web browser interface, is able to compose complex computational tasks represented as a collection of middle‐tier objects serving as proxies for services rendered by the back‐end. The proxies through a Grid resource broker use the Grid services, as defined by the Global Grid Forum, to access remote computational resources. The middle‐tier objects are persistent, and therefore once configured, simulation can be reused, shared between users, or undergo transition into operational or educational use. Copyright © 2002 John Wiley & Sons, Ltd.

High-performance computing and networking as tools for accurate emission computed tomography reconstruction.

It is well known that the quantitative potential of emission computed tomography (ECT) relies on the ability to compensate for resolution, attenuation and scatter effects. Reconstruction algorithms which are able to take these effects into account are highly demanding in terms of computing resources. The reported work aimed to investigate the use of a parallel high-performance computing platform for ECT reconstruction taking into account an accurate model of the acquisition of single-photon emission tomographic (SPET) data. An iterative algorithm with an accurate model of the variable system response was ported on the MIMD (Multiple Instruction Multiple Data) parallel architecture of a 64-node Cray T3D massively parallel computer. The system was organized to make it easily accessible even from low-cost PC-based workstations through standard TCP/IP networking. A complete brain study of 30 (64x64) slices could be reconstructed from a set of 90 (64x64) projections with ten iterations of the conjugate gradients algorithm in 9 s, corresponding to an actual speed-up factor of 135. This work demonstrated the possibility of exploiting remote high-performance computing and networking resources from hospital sites by means of low-cost workstations using standard communication protocols without particular problems for routine use. The achievable speed-up factors allow the assessment of the clinical benefit of advanced reconstruction techniques which require a heavy computational burden for the compensation effects such as variable spatial resolution, scatter and attenuation. The possibility of using the same software on the same hardware platform with data acquired in different laboratories with various kinds of SPET instrumentation is appealing for software quality control and for the evaluation of the clinical impact of the reconstruction methods.

Multi-console intelligent satellite graphics

The Department of the Army has undertaken the development of a graphics design system in order to satisfy a variety of engineering requirements. The system is being developed under the overall project, entitled: “Multidisciplined Engineering Design Evaluation and Analysis (MEDEA).” Goals inherent to the developing system are: hardware independence for local processors and graphic consoles, network orientation for resource sharing: multi-user independent operation and reasonable reaction to satisfy attention requests. The approach taken to realize these goals is one that provides a multi-program, multi-task environment. The environment is provided by an interrupt driven Multi-task Operating System (MTOS) that operates on a priority scheme to govern program execution and resource allocation. The priority system is dynamic in nature and governed by ‘static’, ‘relative’, and ‘time’ factors. Graphic processing is supported at the terminal. Large scale computations are supported remotely at large mainframes. Communications between the terminal and the remote mainframe are managed by a MEDEA Interface program resident at the remote site. The MEDEA interface resolves the peculiarities of the host system and allows the terminal graphic applications to view remote mainframe computational resources in a standard fashion. The hardware comprising the MEDEA design terminal is centered around an intelligent satellite terminal Ipporting a cluster of non-homogeneous graphic consoles. Test bed for the MEDEA design terminal has been implemented and will be used to debug and tune the MTOS system. define the minimum hardware configuration and provide a realistic production environment during system development.