Analyze Scheduling Based On Priority

The main research of this paper is to study the design method of concurrent system based on priority. We focus on the system decomposition and combination method based on priority, propose a method to decompose and combine the system, and prove its correctness. First, we model system with an event-based behavioral model. Next, based on such a model, we formally define the schedule, the scheduling policy and the correctness of a scheduling policy. After that, we propose a method for decomposing and combining schedule policy, and prove the method's correctness. Finally, according to the decentralized and combined method, we develop a toolkit, which supports event-based behavioral model, for modeling system decomposition and combination of scheduling policy. An experiment demonstrates that these results may help engineers to design correct and efficient schedule policies in a system therefore realize decomposition and combination.The detailed contents are as follows:(1) Focusing on analyzing scheduling, we adopt a formal model called a dependent structure which models the concurrent system. Unlike other formal models (e.g. transition systems, Petri nets and process algebras). It can directly specify the dependency relations through regarding events with data information as basic elements and combining data with controlling in the concurrent system. It will benefit to analyze the schedule of the concurrent system.(2) We put forward a system decomposition method based on priority, propose a method to decompose the system, and prove its correctness. At first we model system with an event-based behavioral model and formally define the schedule, the scheduling policy and the correctness of a scheduling policy. After that, we propose a method for decomposing schedule policy, and prove the method's correctness.(3) There is a variety of ways about combination of subsystems. Bad combination will cause some problems that resource is not balanced and the communication cost is large. It will eventually lead to the unreasonable distribution system. Therefore, this paper proposes a method to evaluate the quality of subsystem combinations which makes resource distribution more reasonable and communication more effective. Firstly we define the concepts of combinations of subsystems. Then we define the cohesion, coupling and the independence of the formula. These illustrate the combination measurement method and the method can be used to assess subsystem combination quality.(4) We develop a set of supporting concurrent system prototype tool, not only to achieve the modeling of concurrent systems, and the realization of the decomposition and combination of the basic operations of scheduling, but also to demonstrate the analysis of scheduling method with examples.