The priority inversion problem has been detected two decades ago. The decisive ideas to cope with this problem have been published one decade ago. In the meantime the vendors of operating systems and run–time systems have occupied this topic in providing certain protocols in order to avoid priority inversion. However, at a closer look there are considerable differences in the usage and the resu...

The heap-on-top (hot) priority queue data structure 6] improves on the best known times for Dijkstra's shortest path algorithm. It also has very good practical performance and is robust over a wide range of graph types. The heart of Dijkstra's algorithm is a monotone priority queue, that is, a priority queue where no element on the queue ever becomes smaller than the most recently extracted ele...

This paper presents the A ected Set Priority Ceiling Protocols (ASPCP) for concurrency control in real-time object-oriented systems. These protocols are based on a combination of semantic locking and priority ceiling techniques. This paper shows that the ASPCP protocols provide higher potential concurrency for object-oriented systems than existing Priority Ceiling protocols, while still boundin...

countries around the world are experiencing an ever-increasing need to make choices in investments in health and healthcare. this makes it incumbent upon them to have formal processes in place to optimize the legitimacy of eventual decisions. there is now growing experience among countries of the implementation of stakeholder participation, and a developing convergence of methods to support dec...

This paper is concerned with the stability of a preemptive repeat priority queueing system with multiple types of customers and customer transfers between queues. Using the mean-drift method and matrix-analytic methods, simple conditions for the queueing system to be stable or instable are found. The conditions indicate that system stability depends only on the service rate of customers of the ...

We obtain an essentially optimal tradeoff between the amortized cost of the three basic priority queue operations insert, delete and find-min in the comparison model. More specifically, we show that A(find-min) = Ω ( n (2 + )A(insert)+A(delete) )

We study MX/G/1 nonpreemptive and preemptive-resume priority queues with/without vacations under random order of service (ROS) discipline within each class. By considering the conditional waiting times given the states of the system, which an arbitrary message observes upon arrival, we derive the Laplace-Stieltjes transforms of the waiting time distributions and explicitly obtain the first two ...

A new priority queue structure is introduced, for which the amortized time to insert a new element isO(1) while that for the minimumextraction is O(logK). K is the average, taken over all the deleted elements x, of the number of elements that are inserted during the lifespan of x and are still in the heap when x is removed. Several applications of our structure are mentioned.