1. Service Architecture of Grid Faults Diagnosis Expert System Based on Web Service Wang Mingzan, Zhang ziye Northeastern University, Shenyang, 110004 China The Eighth International Conference on Electronic Measurement and Instruments ICEMI’2007

2. Outline Introduction OGSA ( Open Grid Services Architecture ) –OGSA Based on Web Services –Grid Service Layer Base on OGSA Application –Grid Nodes of Fault Diagnosis Expert Systems –Data Transfer Conclusion

3. Introduction With the advance of computer technology, the scale and complexity of modern system is increased dramatically. Once some accidents take place, it will lead to tremendous loss. The appearance of faults diagnosis and fault- tolerant controlling technology opens a new path for advancing the reliability of complex system. The grid computing technology was firstly used in faults diagnosis expert system in the paper.

4. OGSA ( Open Grid Services Architecture ) –OGSA Based on Web Services –Grid Service Layer Base on OGSA Open Grid Services Architecture

5. OGSA Based on Web Services User Firstly, client send request to the Servlet (Web service layer) residenting on Web server through browser. Servlet is responsible for calling corresponding EJB (Enterprise Java Beans) components on application server. The activated component accesses the backend data layer and processes the data.

6. OGSA Based on Web Services Then Servlet chooses the appropriate JSP program (Web service layer) and transfers the result, JSP returns the result in the form of HTML to browser. Client can be the Java application procedure, CORBA customer or the service partner. They separately communicate with the EJB component through the different protocol.

7. OGSA ( Open Grid Services Architecture ) –OGSA Based on Web Services –Grid Service Layer Base on OGSA Open Grid Services Architecture

8. Grid Service Layer Base on OGSA The grid services include procedure execution, data service, and so on. With the appearance of these services, OGSA will turn into useful Service- Oriented Architecture (SOA).

9. Grid Service Layer Base on OGSA The strategy of task dividing will affect directly the load balance, the communication complexity and the dependence of the tasks (1) Based on the deserializing analysis, develop the public service and the parallel service in server. This step needs to deploy every parallel service to all nodes in the grid. (2) According to the number of parallel nodes in the grid, call threads in the client, each can visit the parallel service. (3) Monitor the status of these threads, perform fault diagnoses and compile the result.

10. Grid Service Layer Base on OGSA DGMA Based on Fault Diagnosis Expert Systems

11. Grid Service Layer Base on OGSA In the solution above, the server end in the grid nodes process main service logic, the client end need only start multi-threads to call and monitor the completion condition of service. Therefore, it reduces the client’s load and achieves the application deserializing.

12. Application –Grid Nodes of Fault Diagnosis Expert Systems –Data Transfer

13. Grid Nodes of Fault Diagnosis Expert Systems The server is composed of two grid nodes. They are grid nodes for spectral analysis and the data trend analysis respectively. Java language is used to write Web Service program, which realizes the grid computation and access process in the clients and the servers. the grid nodes can also analyze the load of current node. So it can schedule the grid-cell resources more reasonably, which is especially important for the application of large-scale grid.

14. Application –Grid Nodes of Fault Diagnosis Expert Systems –Data Transfer

15. Data Transfer The experimental environment of the design is established in LAN. We use 4 PC to construct a grid middleware. In Grid-based Fault Diagnosis Expert System, the data transfer uses the way of GridFTP Then used API function to realize data transfer through Java Cog Kit.

16. Data Transfer (1) Establish a Spec of transmission task, this Spec is similar to RSL; (2) Set the source address and the destination address in transmission, and begin using the third party to transmit; (3) Establish a transmission serve for the data resources of the source address; (4) Establish a transmission service for the data resources of the destination address; (5) Join the source address service and the destination address service to the service, in order to realize data transmission between two services; (6) Submit the duty and realize data transmission.

17. Data Transfer The system uses API provided by Java Cog Kit to carry out service submission. Cog Kit uninterruptedly intercepts execution status of accepting the work node through Status Listener. In Cog Kit, the execution situation of work is SUBMITTED, FAILED and COMPLETED Respectively. In the client-end, we maintain a thread table. It includes thread number, state (0, moving; 1, moving failure; 2, normal terminating)

18. Data Transfer Through above application, it can reduce the transfer latency brought by the network. Moreover, the jobs are not uniformly allocated through the GFDES interface at the same time. Consequently, the communication bottleneck is avoided.

19. Conclusion When construct GFDES based on the Web Service, the public service and the parallel service can enhance the sharing of application code. It makes the application more flexible through the unified way of the service and the job, and increases the efficiency of several jobs parallel with the aid of the Java’s multi-threading.