<TicketDate>02/06/2014< /TicketDate>
< /Ticket>
<Ticket>
<TicketID>0122< /TicketID>
<TicketType>single< /TicketType>
<TicketDate>02/06/2014< /TicketDate>
< /Ticket>
< /Tickets>
< /TicketLouveMuseum>
The other is for condition that If Weather returns ”Sunny”:
<TicketEuroDisney>
<Status>paid< /Status>
<Tickets>
<Ticket>
<TicketID>0514< /TicketID>
<TicketType>family< /TicketType>
<TicketDate>02/06/2014< /TicketDate>
< /Ticket>
< /Tickets>
< /TicketEuroDisney>
of service execution in xml document contains root element as BookingRestau- rantResveration,Direction which matches to predefined BookingRestaurantResvera- tion,Direction in Alice’s goals. For lastly Experiment 3, a result in Figure 5.10 shows a composite model supporting conditioning constructs among service op- erations: GetWeatherForecast, BuyTicketLouveMuseum and BuyTicketEuroDisney operations. A result of this service execution has two optional outputs. It re- turns a result in xml document containing root element as TicketLouveMuseum if the GetWeatherForecast operation return no Sunny for Weather value, which matches to predefined TicketLouveMuseum, Condition(if(Weather /== Sunny)) in Alice’s goals. Whereas another result in xml document containing root element as TicketEuroDisney is returned if the GetWeatherForecast operation return Sunny for Weather value, which satisfies with Alice’s query expression TicketEuroDisney, Condition(if(Weather == Sunny)).
Conclusion and Future work
Contents
6.1 Future work . . . 108
Abstract. In this Chapter, we conclude the research and offers future research recommendations.
In this dissertation, we investigated a problem of Automated Service Composition and Execution in static execution environment. We proposed a framework for (1) composing automatic service operations, so that a BPMN composition model fulfills both BPMN specification and defined user’s goals at the same time and (2) executing the BPMN model with user’s parameters, so that the result of service execution returns to the user.
On the basis of our composition technique, we defined user requirements expressed in a sequence of goal states in propositional logic. We show how our planning al- gorithm is working with abstract goal states to search and connect to service operations, by mean of service operation annotations, for a solution. The solution is expected for workflow model of sequencing, paralleling and conditioning among service operations. To allow for more expressive control flow requirements, we proposed our own abstract (context based) language that introduces the following features: the ability to express both reachability and procedural goals and the ability to set preferences among alternative goals. On the basis of our BPMN transformation technique, we defined reasonable semantics for BPMN elements
106
for mapping context-based composition model into BPMN model in Prolog decla- ration. We proposed a new planning algorithm and exploited planning-as-model- checking approach developing the idea of [MPT08] to validate the Prolog BPMN model whether it is Well-formed and Well-defined BPMN process.
On the basis of our service execution technique, we implemented algorithm to checking missing parameters from the derived initial states and we implemented BPMN diagram and BPMN model in xml format from open source BPMN Ac- tiviti API. Finally, we executed the BPMN model with the input parameters and returned the result of the execution to the user.
One of the key contributions of the thesis is the Service Composition and Execu- tion demonstration platform. In it, we modeled a pervasive system based on the E-Tourism scenarios and realized workflow composition, BPMN transformation, validation and implementation and execution of BPMN models using our Service Composition and Execution framework.
The platform allowed us to evaluate not only the integrability of multiple domains for our Service Composition and Execution approach but also the performance of the composition and execution engines on dynamic related scenarios.
Through out this research, we found the added values and limitations of our work.
The proposed service composition and execution system framework is a generic approach suitable for most domains on component integration. The prototype developed in this thesis is for the module Composition and Orchestration System (COS) which will be integrated in the E-Tourism system. Additionally, the pro- totype is designed to handle both push and pull modes in the E-Tourism system.
However, our framework relies only on function call (input(s) and output(s)) of service operation annotations. We did not use other service informations such as preconditions and effects, which allow users to make more complex queries.
Furthermore, our composition approach supports only automatic tasks such as service tasks and script tasks in business process model. Besides, the business process model does not handle its non-functional features (i.e., artifacts and asso- ciation) and organizational modeling features (i.e., lanes and pools). Lastly, we do not support process monitoring and controlling when our process engine executes the business process model.
As a matter of fact, within this dissertation we could not handle every single issue related to the topics of interest. We admit that there are still many extensions
and improvements are needed to make the approaches more mature and effective.
The following we shall discuss the most important issues we plan to take in the near future.