Report For Research Project


Title
The Rate-Based Execution Model

Keyword
I want to present a task model for the real-time execution of event-driven tasks in which no priori characterization of the actual arrival rate of events is known,only the expected arrival rate for event is known.This task model is called rate-based execution(RBE),the RBE model is motivated natually by distributed multimedia and digital signal processing application

Background and outline
1. Background:
Real-time application frequently interact with external devices in an event-driven manner.The delivery of a message ,or a hardware interrupt ,signals the event arrival.A task is then dispached to process the event.In real-time environments ,the system provides some form of guarantee that the task will finish processing the event within d time units of the event occurrence.where di is called the relative deadline of event ei,Hard-real-time systems guatantee that every event ei will be processed within di time units of its occurrence.Soft-real-time systems provids weaker guarantees of timeliness
2. Outline:
(1). RBE Task Model
(2). Feasibility of RBE Tasks
(3). Discussion
(4). Summary and Conclusion

Approach
1.The starting point for my work is to study the model of sporadic tasks developed by Mok,and later extended by Baruah and Jeffay .
2.Alter the formal model to account by extending the sporadic task to be a task that executes at an average rate.
3.The RBA task model is most similar to the linear-bounded arribal process(LBAP)model used in the DASH system.I want to generalizes the LBAP model to include a more generic specification of rate and adds an independent response time parameter to enable more precise real-time control of task execution,
4.Analyze the model in more complex environments such as those wherein tasks communicate vis memory and thus have preemption constraints.

Current progress of research
My research plan is as follows:
1. I will finish studying the model of sporadic tasks in 2 weeks.
2. Study the LBAP model for one week.
3. Alter the formal model to account for the requirement in 3 weeks.
4. Analyze the model in more complex environments
Now I am under the study of the model of sporadic tasks.And may finish it this week and go on with the LBAP model study.
I will try to finish all the plans on time and get the conclusion till the end of July.