Method for Web Services QoS Observation and Dynamic Selection

Abstract

A system and method permits a user to observe the Quality of Service (QoS) of Web services and allows dynamic selection based on the user's preference. The system is built on QoS observation meta-model and comprises a QoS observation manager, service criteria generator, service repository, evaluation manager and service invocation manager. The QoS observation manager allows users to define observation model and deploy to the service criteria generator. The service criteria generator computes the QoS criteria values of services by subscribing events, which include user feedback events and service execution events, based on deployed observation model. The service repository provides the persistence storage for QoS criteria value. The evaluation manager allows users to specify selection preferences and select services based on QoS ranking. The service invocation manger invokes Web services and publishes events according to the QoS of Web services. The system enables users to observe the QoS of Web service and select Web service based on QoS ranking that reflects the user's selection preference.

1 - 6 . (canceled) 
   
   
       7 . A method of computing Quality of Service (QoS) information of a Web service, comprising the steps of:
 defining an observation model for QoS of the Web service;   deploying the observation model to generate runtime code for QoS information computation;   subscribing events on QoS of Web services based on observation model;   collecting user feedback information;   recording QoS execution information during the Web service invocation; and   computing QoS information of Web service based on subscribed events.   
   
   
       8 . The method recited in  claim 7 , further comprising the step of correlating primitive events to composite events. 
   
   
       9 . The method recited in  claim 7 , further comprising the step of evaluating the evaluation polices. 
   
   
       10 . The method recited in  claim 7 , wherein said subscribing events step is based on an event subscription repository which is generated based on dependence expression, evaluation policies of criteria. 
   
   
       11 . The method recited in  claim 7 , wherein said step of computing QoS information of Web service is based dependence expression specification repository, and further comprising the step of executing dependence expression and score function. 
   
   
       12 . The method recited in  claim 7 , wherein said step of deploying an observation model further comprises the step of generating entries for dependence expression specification repository and event subscription repository. 
   
   
       13 . A method of ranking Web service based on Quality of Service (QoS), comprising the steps of:
 normalizing the value for each QoS criterion score value;   filtering inefficient Web service via generating a convex hull; and   ranking the QoS of a candidate Web service via user configurable utility function over multiple criteria.   
   
   
       14 . The method recited in  claim 13 , wherein the step of filtering inefficient Web service is based on two dimensional or three dimensional convex hull generations and removing a Web service inside the convex hull.