In this chapter we present recent contributions in the field of sequential job scheduling on network machines which work in parallel; these are subject to temporary unavailability. This unavailability can be either unforeseeable (online models) or known a priori (offline models). For the online models we are mainly interested in preemptive schedules for problem formulations where the machine un...

Recipients of a partially T-cell–depleted (TCD) allogeneic stem cell transplantation (allo-SCT) developing reactivation of Epstein-Barr virus (EBV) with quantified viral DNA levels exceeding 1000 genome equivalents/milliliter (geq/mL) are at high risk for EBV–lymphoproliferative disease (EBVLPD). We studied whether preemptive therapy with rituximab prevents EBV-LPD, LPD-mortality, and abrogates...

Recipients of a partially T-cell-depleted (TCD) allogeneic stem cell transplantation (allo-SCT) developing reactivation of Epstein-Barr virus (EBV) with quantified viral DNA levels exceeding 1000 genome equivalents/milliliter (geq/mL) are at high risk for EBV-lymphoproliferative disease (EBV-LPD). We studied whether preemptive therapy with rituximab prevents EBV-LPD, LPD-mortality, and abrogate...

This paper considers three variants of last-come first-served (LCFS) preemptive service single-server queues, where customers are served under the LCFS preemptive resume (LCFS-PR), preemptive repeat-different (LCFS-PD), and preemptive repeat-identical (LCFS-PI) disciplines, respectively. These LCFS queues are fed by multiple batch Markovian arrival streams. Service times of customers from each ...

This paper is concerned with the problem of scheduling preemptive tasks subject to precedence constraints in order to minimize the maximum lateness and the makespan. The number of available parallel processors is allowed to vary in time. It is shown that when an Earliest Due Date rst algorithm provides an optimal nonpreemptive schedule for unit-execution-time (UET) tasks, then the preemptive pr...

Preemptive multi-tasking is a commonly used architecture for designing and implementing embedded real-time software. However, preemptive multi-tasking comes with its own costs. These costs include overheads due to preemptions and context-switches that result in waste of CPU bandwidth. Also, each task incurs a memory cost largely due to the need to maintain a separate stack for each task. These ...

This paper explains how DiffServ has been implemented in an IP network simulator using an asynchronous conservative parallel discrete event simulation (PDES) kernel. DiffServ provides Quality of Service (QoS) functionality for IP networks and is designed to provide greater scalability and lower overhead than previous IP based QoS schemes. The paper explains the DiffServ components that have bee...

Acknowledgement I would like to express my sincere acknowledgements to the Mälardalen University and East China University of Science and Technology for the precious chance they have provided to realize and complete my one year study here with my total satisfaction. Special appreciation goes to Dr. Radu Dobrin, Dr. Moris Behnam, Abhilash Thekkilakattil for giving me all the support that I neede...

In this paper, we compare the makespan of preemptive and i-preemptive schedules where only a limited number i of preemptions is allowed. The problem is to schedule n independent jobs on m identical processors that operate in parallel. The objective is to minimize the makespan, i.e., the completion time of the last job that finishes. We show that the ratio of the optimal ipreemptive schedule len...

For many queueing systems the server is not continuously available. Service interruptions may result from repair times after server failures, from planned maintenance periods or from periods during which customers from other queues are being served. These service interruptions cause an overall performance degradation which is most striking when interruptions can start while a customer is being ...