Investigation Of The Technologies Of Equipment Grid For Sharing Experimental Resources

Experimental teaching is indispensable to higher education. It trains students'ability to apply theory to practice, and improves their innovation thinking and skill. However, there is a shortage of teaching experimental resources, both experimental rooms and experimental equipments, in colleges because the total budget for the education resources is limited in China. Thus, online experimental teaching applications driven by the information technology have become good examples that combined scientific research with teaching, and also have been approaches to cover the shortage of experimental resources. Online laboratories, which share teaching experimental resources by network, face the request for integrating heterogeneous resources to provide the unified services, when they developed from the individual systems based on web page to the distributed ones based on web service. Then the development of grid, from computing grid to service grid, constructs a software framework for this request. The research of the equipment grid for sharing experimental resources is for the meet of teaching experimental environment needs.Since the equipment grid for sharing experimental resources is a service gird with the particularity of resource, its system architecture has the common features of service grid. Nevertheleas it has its own peculiar meaning. The model of the equipment grid for sharing experimental resources described its architecture formally with discrete mathematics tools. And this model was composed of grid resources, gird services and grid users in four-level structures. The key concepts in architecture of grid, such as the physical resource, experimental grid service and virtual experimental course, were defined respectively in the model. Consequently, this model was laid the foundation of the investigating the theory of equipment grid.For the diversity of experimental equipments, the resources have the different standards of the ability evaluation and the methods of the task assignment。Therefore, the scheduling strategy for experimental resources was designed, based on the current classification of experimental resources. The weights of the resources were used in the oriented system level and the classical evaluations of the resources were used in the orient application one. The experimental tasks of the resources with the different weights were scheduled by priority in the strategy, and the ones of the resources with the different types were scheduled with the different methods of the ability evaluation and the algorithms of the task assignmen.Most of the experimental equipment resources are more stateful, which some experimental courses request clients to manage interactively their state transitions. Although Web Services Resource Framework (WSRF) specifications have offered the method of modeling the stateful resource, but it can not deal with the problems of the state transitions. For the management of the state transition in life cycle, Web Services Resource Finite State Machine Document (WSFSMD) and the service interface according to the WSRFSMD, as a useful supplement of WSRF were put forword. The method of describing the state machine of resource and the method of accessing this description were provided by the WSRFSMD. They allowed clients to control automatically the state transitions of the resource in its life cycle.The equipment grid for sharing experimental resources includes the diverse experimental equipments. The diversity of those resources causes the complexity of the information management of the resources. Accordingly, the UDDI based two-level information service for equipment grid was developed. The information of equipment resource was dividesd into two parts of the static information and the dynamic one in this system. The classification mechanism in UDDI was combined with the management of resource property in MDS4. And then they were related to manage respectively two parts of information. The UDDI based two-level information service for equipment grid took full advantage of the information management characters of these components and attained their complementary strengths in order to improve the efficiency of information management in equipment grid.As the important component of distributed system, the message mechanism supports the communication among the components under the heterogeneous environment, and improves the interoperability, the scalability, the flexibility of the distributed system. The message mechanism in equipment grid was developed. Based on the subdivision of the component functions, a grid message was definedby this message mechanism. The resource properties were related with the functional components by the grid message. And then, the process of the discovering and monitoring resources were changed into the one of the creasing and delivering event messages in this message mechanism. Consequently, the problems was resolved, which the increase of the cost of component update and the decrease of the flexibility of grid were caused by the tight coupling between the grid functional component and grid resource property. The prototype of the equipment grid for sharing experimental resources was constructed as the study platform of the technology of equipment grid, which was built up on the Globus Toolkit 4. This prototype has realized the several functions, from integrating experimental resources to scheduling experimental tasks. Consequently, the whole online experimental course, from discovering experimental resources to completing experimental tasks was implemented in this prototype.