We consider the on-line scheduling problem of jobs with precedence constraints on m parallel identical machines. Each job has a time processing requirement, and may depend on other jobs (has to be processed after them). A job arrives only after its predecessors have been completed. The cost of an algorithm is the time that the last job is completed. We show lower bounds on the competitive ratio...

Most multiprocessors are multiprogrammed in order to achieve acceptable response time and to increase their utilization. Unfortunately, inopportune preemption may significantly degrade the performance of synchronized parallel applications. To address this problem, researchers have developed two principal strategies for concurrent, atomic update of shared data structures: (1) preemption-safe loc...

Extensive research has been devoted to resource constrained project scheduling problem. However, little attention has been paid to problems where a certain time penalty must be incurred if activity preemption is allowed. In this paper, we consider the project scheduling problem of minimizing the total cost subject to resource constraints, earliness-tardiness penalties and preemption penalties, ...

Important classical scheduling theory results for real time computing are identi ed Im plications of these results from the perspective of a real time systems designer are discussed Uni processor and multiprocessor results are addressed as well as important issues such as future release times precedence constraints shared resources task value overloads static versus dynamic scheduling preemptio...

In this paper, we study preemption primitives in reactive languages such as Esterel and Signal (and its extension SignalGT_) in a common framework. This enables us to compare behavioural/structural expressive powers of diierent languages and gives an insight into the complementarity of diierent control and data-ow abstractions in the reactive languages. Such a study also provides a basis on whi...

This article explores the key issues involved in understanding the impact of Medicare preemption on state laws affecting the federal purchase of managed care products, as a consideration in future Medicare reform. Author Commander Jackonis argues that any further Medicare reform must address the impact of federal preemption on quality and quantity of care purchased in order to ensure the existe...

In this paper, we study preemption primitives in reactive languages such as Esterel and Signal (and its extension SignalGT_) in a common framework. This enables us to compare behavioural/structural expressive powers of diierent languages and gives an insight into the complementarity of diierent control and data-ow abstractions in the reactive languages. Such a study also provides a basis on whi...

An ambulance or fire truck arriving a couple of seconds late can be the difference between life and death for some. As different technologies emerge, various approaches to expediting the movement of emergency vehicles have evolved. Horns, sirens and flashing lights were early attempts that are no longer sufficient in most places to clear traffic on the emergency vehicle’s route. In these situat...