AbstmctA direct application of commonly used synchronization primitives such as semaphores, monitors, or the Ada rendezvous can lead to uncontrolled priority inversion, a situation in which a higher priority job is blocked by lower priority jobs for an indefinite period of time. In this paper, we investigate two protocols belonging to the class of priority inheritance protocols, called the basi...

We study the problem of priority inversion in distributed real-time and embedded systems and propose a solution based on a distributed version of the priority inheritance protocol (PIP). Previous approaches to priority inversions in distributed systems use variations of the priority ceiling protocol (PCP), originally designed for centralized systems as a modification of PIP that also prevents d...

This paper describes the experience of implementing CBQ's top-level link sharing code as described previously in [FJ95]. This implementation incorporates work from previous implementations of Class-Based Queueing from LBNL [Jac95] and UCL [WGC 95]. This implementation extends the work of previous implementations by incorporating both Top-Level link-sharing and Weighted Round Robin within priori...

In this paper we discuss term-rewriting systems with ru/e prioriries, which simply is a partial ordering on the rules. The procedural meaning of such an ordering then is, that the application of a rule of lower priority is allowed only if no rule of higher priority is applicable. The semantics of such a system is discussed. It turns out that the class of all hounded systems indeed has such a se...

This paper presents a branch-and-price algorithm for scheduling n jobs on m nonhomogeneous parallel machines with multiple time windows. An additional feature of the problem is that each job falls into one of ρ priority classes and may require two operations. The objective is to maximize the weighted number of jobs scheduled, where a job in a higher priority class has “infinitely” more weight o...

The Heidenhain variant defines a peculiar clinical presentation of sporadic Creutzfeldt-Jakob disease (sCJD) characterized by isolated visual disturbances at disease onset and reflecting the early targeting of prions to the occipital cortex. Molecular and histopathological typing, thus far performed in 23 cases, has linked the Heidenhain variant to the MM1 sCJD type. To contribute a comprehensi...

 This study considers a system of multi-server queues with two classes of impatient customers: high-priority and low-priority. Customers join the system according to a Poisson process and customers may abandon service after entering the queue for an exponentially distributed duration with distinct rates. In this paper, we consider last come-first served (LCFS) and first come-first served (FCFS...

water crisis resource management originates from limited resources has made it essential to study the prioritization of traditional and modern methods of sustainable water resource management. the objective of such studies is to provide a list of prioritized traditional and modern methods of sustainable water resource management. this research aims to study rainwater harvesting method and qanat...

When there are different customer classes in a queue system, the j-th class customers have their services before j+1,j=1,2,… customers. Such queues named as with priority scheduling. In this study Markov system two is analyzed both under non-pre-emptive and nonpriority scheduling efficiency measures (the expected number of average waiting time system) obtained using Little’s Law. The criteria c...

This paper considers a Markovian model of a service system motivated by communication and information services. The system has finite processing capacity and offers multiple grades of service. The highest priority users receive a “guaranteed” processing rate, while lower priority users share residual capacity according to their priority level and therefore may experience service degradation (he...