Grid Services Workflow And Resource Management Based On Petri Net And Agent

Grid Services Workflow has become a hotspot in Grid research field, up to now, there hasnot been complete system framework, and hence can't analyze safety and flexibility ofworkflow exactly and make an effective judgment for design and verification of Grid ServicesWorkflow. There exists massive Grid services of all kinds in Wide-area distributed Gridenvironment, for a Grid application, how to find Grid service satisfying its requirement, i.e.service discovery, is a very important research issue. In addition, a single Grid servicesometimes can't fulfill a Grid application all by itself; therefore, it is required to studycomposition mode and cooperation mechanism among Grid services.This dissertation focuses on the key problems described above such as Grid ServicesWorkflow model, Grid services discovery, Grid services composition, etc. based on Petri nets,Agent and Web Services. The main contributions are listed as follows.1) As for the modeling power of time Petri net (TPN), this dissertation gives a proof thatshows that TPN has the same modeling power as the Turing Machine for the first time. Inaddition, it presents a method of transforming a timed Petri net, another Petri net which has timefactors, to a TPN; this indicates that TPN is not inferior to other Petri net with time factorsdespite its simple structure and also presents another efficient method of studying timed Petrinet as well.2) As for the liveness and boundedness of TPN, this dissertation shows that TPN'sliveness and boundedness behavior has no relation with its corresponding classic Petri Netthrough some examples, then presents two sufficient and necessary conditions in time intervalof TPN preserving liveness and boundedness. It is easy to judge a TPN's liveness andboundedness according to the result.3) As for Grid Services Workflow, this dissertation presents a Grid Services WorkflowSystem framework based on Colored Petri nets (CPN), Web Services and Agent technologies.How Web services can be located dynamically and the services provided by them can beinvoked are discussed. It also shows how the Agents and Web Services can coordinate to createhighly flexible and dynamic Grid Services Workflow System and how the framework can beused to achieve adaptability from a process, resource and task perspectives. 4) As for Grid Services discovery, this dissertation presents a multi-agent-based Gridservice discovery framework. A Fuzzy Petri nets-based service description language isproposed as a specification to publish or request for a service. Meanwhile, through ontology'sclass hierarchy, we put forward a semantic-based service matchmaking algorithm that can findan appropriate service for a request. Possibility and necessity measures are used to quantify theconfidence levels that the service can satisfy a request, that is, this algorithm supports partialmatching.5) As for Grid Services composition, this dissertation proposes a CPN-based Grid Servicescomposition model. Firstly, CPN is used to model the operations/activities provided by Gridservice. Then the CPN models for4basic combination styles (sequence, concurrence, choiceand iteration) among operations are given. Finally, a construction algorithm of Grid servicecomposition is presented. The proposed CPN model can express the logic of composite serviceand describe the relationship among services clearly. System's behavior can be modeled and theproperties--boundedness, liveness, reachability, etc. can be analyzed through CPN Tools.