Rate Monotonic scheduling algorithm has been widely used in real-time systems for its optimality in fixed priority scheduling. Determining the Rate Monotonic schedulability of tasks is an important problem when designing a real-time system. There are exact schedulability test methods for Rate Monotonic scheduling, but the worst case response time analysis on which the exact tests are based is NP-hard. So the exact tests are often too complex to be executed on-line for large numbers of tasks. For practical use, polynomial time sufficient conditions for the Rate Monotonic schedulability have been studied. However, existing polynomial time tests are often too pessimistic. In this paper, we propose a new polynomial time sufficient condition based on the response time analysis, which is less pessimistic than existing ones. Simulation results show that our test significantly outperforms the existing tests and has performance close to the exact test.

Fixed priority scheduling is an important real-time scheduling scheme widely used in practice. To improve the schedulability of fixed priority scheduling considerable effort has been made such as introduction of preemption threshold or deferred preemption, and quantum-based scheduling. In this paper, we develop a new scheduling scheme by introducing both preemption threshold and quantum into one scheduling framework. The new scheduling method may successfully schedule tasks which are not schedulable either by preemption threshold scheduling or quantum-based scheduling, as well as tasks schedulable by either scheduling, thus improves the schedulability of fixed-priority tasks. We analyze the schedulability of the new scheduler by computing the worst case response time of tasks. Based on the analysis, we developed an algorithm for assignment of preemption threshold and quantum sizes.

Automated tests are important for Web applications as they grow more complex day by day. Web application testing frameworks have emerged to help satisfy this need. However, used without a model that is designed for system evolution and realization, maintaining test code becomes cumbersome and inefficient. This paper describes an activity oriented approach to engineer automated tests for Web applications with reference to a Web application developed for grant funding agencies. In this approach, the developer defines a domain model to represent application state, and uses a test activity graph comprised of self-validating user interactions to verify application correctness. We have implemented a test code generator called iTester using activity-oriented approach.

Addresses the problem of deciding the feasibility of hard real-time periodic tasks. It is known to be a co-NP problem to determine whether a task set is feasible on one processor when there exists a task with a relative deadline that is shorter than its period in the task set. For synchronous task sets, "processor demand analysis" (PDA) has been considered as a practical tool to solve the feasibility problem. PDA determines the feasibility of a task set by checking whether a deadline is missed in an interval of finite length; this time interval is called the "test interval". The efficiency of a feasibility test method depends on the length of the test interval. In this paper, we present a new method for the feasibility testing of hard real-time periodic tasks. We show theoretically that the length of the test interval in our algorithm is shorter than or equal to existing ones. We also present experimental results that show the length of the test interval in our algorithm is, on average, significantly shorter than existing ones.