Research On Some Key Technologies Of The Water Science Grid

Water science grid is a kind of application grid, which was designed to provide a comprehensive grid-based problem solving and cooperative work environment for the domain of water science and hydraulic engineering, and to provide an effective management mechanism for the integration, configuration, execution and performance optimization of domain-specific applications. This paper researches some key technologies on the grid architecture, grid application framework and methodologies for performance optimization of grid-based applications. The main work and contributions are described as following:(1) The research of the architecture of water science grids. First, based upon the Open Grid Service Architecture (OGSA), an architectural model for water science grids that conforms to the specification of service-oriented computing (SOC) was proposed. Second, to solve problems about the resource abstraction, service provision, system integration and execution management, a grid execution management mechanism coupling the grid application framework and performance optimization methodologies was set up. And last, to maximum satisfy the requirements of the domain-specific applications, a prototype of the water science grid, named e-Water in this paper, was realized.(2) The research of grid application framework. First, by using state-of-the-art grid and Web computing technologies, and by referencing the OGSA grid service framework, a meta-model of grid application framework (GAF) was proposed. Second, by improving and extending the task/channel programming model for distributed heterogeneous computing, a three stages unified programming model based upon "Service contracts construction-End points properties definition-Dynamic service binding" was proposed. And last, by referencing IBM's grid application framework for java (GAF4J) and NEReSC's Web Service grid application framework (WS-GAF), a SOC based grid application framework for e-Water was realized.(3) The research of methodologies for optimizing the performance of grid applications. First, to realize objectives of best performance both for grid and grid applications, a performance manipulating model based on "Aware, Planning and Control" was proposed. Second, according to techniques of the PERT net and the Min-max speedup strategy, an approach to tune the performance of grid-based applications, in which a mechanism of bi-directional adjusting the application architecture and the task dispatching were employed, was proposed. And last, by using technologies of discrete event modeling based simulation, and by referencing famous grid simulation system in the world such as MicroGrid, SimGrid, GridSim and etc., a simulator and some key algorithms for e-Water was realized, which can model the performance both of grid and grid application in different scenarios of resource configuration and service binding.(4) Case study. First of all, based upon the e-Water grid, a flood mitigation operation system for large-scale river basins was realized, including some key algorithms such as the directed parallel solver for hydrodynamic models, and algorithms for parallel and progressively incremental simulation cloning (PPISC) of alternative scenarios of flood mitigation operations. Second, based on computational features of each module in the system, the requirements of grid resource were analyzed, and deployment scenarios of the system were discussed. Third, based on performance tuning approaches proposed in the front of this paper, a performance model for the system was set up, and different scenarios of resource configuration and service deployment were simulated. And last, the system was tested by using two real flood mitigation operation cases in 1996, 2003. Theoretical analysis and test results both manifest that, by using the key technologies proposed in this paper, the optimized PPISC has approximately linear speedup, the precision of computations was increased and the whole performance of the system was improved.