The "Grid" was coined in the mid1990s to denote a proposed distributed computing infrastructure for ad-vaced science and engineering. Now, it has emerged as an important new field. Grid computing can be defined as co-ordinated resources sharing and problem solving in dynamic , multi-institutional virtual organizations. In this paper,we introduce the idea of virtual organizations, present characteristics and requirments of virtual organizations resoucessharing , some important terms in Grid technologies are defined, and principle fundementals and critical ideas of Gridarchitecture are disscussed.
Grid Technologies proposed by Globus project has been used to establish,manage,and exploit cross-organi-zational vitual organizations sharing relationships. Grid technologies are structured by the Grid architecture. The Gridarchitecture is an extensible and open architectural structure which identifies fundamental system components,speci-fies the purpose and fuctions of these components,and indicates how these components interact with one another. Inthis paper ,The Globus project and leaders of itare introduced brifly,then description of various layers of the Grid ar-chitecture including their purposes and functions are presented in detail, and Grid protocols & sevices(and APIs) de-fined in Globus Toolkits and Grid architecture in practice are also disscussed.
In this paper, a nonautonomous predator-prey dispersion model is studied, where all parameters are time-dependent. The system, which is consisted of n-patches, the prey specics can disperse among n-patches, but the predator species is confined to one patch and cannot disperse. It is proved the system is uniformly persistent under any dispersion rates effect. Furthermore, sufficient conditions are established for global stability of the system.
