System and method for web service QoS observation and dynamic selection

• US 20060036752A1
• Filed: 08/12/2004
• Published: 02/16/2006
• Est. Priority Date: 08/12/2004
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Zeng, Liangzhao, Lei, Hui
• Granted Patent: US 7,386,620 B2
• Time in Patent Office: Days
• US Class Current: 709/229
• CPC Class Codes: H04L 67/61 taking into account QoS or priority requirements

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.

Claims

1. A system for observing of Web services Quality of Service (QoS), comprising:

a service criteria generator which computes QoS criteria values of services by subscribing user feedback events and service execution events, based on a deployed observation model;

a QoS observation manager which allows users to define an observation model and deploy to the service criteria generator;

a service repository which provides persistent storage for QoS criteria values;

an evaluation manager which allows users to specify selection preferences and select services based on QoS ranking; and

a service invocation manger which invokes Web services, collects user'"'"'s feedback on usage of Web services and publishes events according to the QoS of Web services.

2. The system recited in claim 1, wherein a QoS observation manager provides tools and meta-models that allow observation model developers to define an observation model.

3. The system recited in claim 2, wherein said observation model includes a set of QoS criteria.

4. The system recited in claim 3, wherein QoS criterion includes a data type for storing raw information about the Web services'"'"' quality, a score function, a dependence expression and an evaluation policy.

5. The system recited in claim 1, wherein said criteria generator comprises:

an observation model loader which loads the observation model specification into the system;

an event filter which subscribes events from an event bus based on event specification repository and correlates primitive events to composite events and notifies the criteria evaluator;

a criteria evaluator that evaluates evaluation policies to check which dependence expression needs to be computed in order to create or update a value of criteria for a Web service;

a dependence expression specification repository that stores dependence expressions, score functions and evaluation policies for each criteria; and

an event specification repository that stores event specification that is subscribed by the criteria generator.

6. The system recited in claim 1, wherein the evaluation manger provides user interface that allows Web service users to specify a service selection preference by giving two or three most important dimensions, creates a two dimensional or three dimensional convex hull to exclude efficient Web services, and selects Web service by utility function.

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.