This paper analyzes fluid scale asymptotics of two models generalized Jackson networks employing the earliest deadline first (EDF) policy. One applies ‘soft’ EDF policy, where deadlines are used to determine priority but jobs do not renege, and other implements ‘hard’ EDF, renege when expire, postponed with each migration a new station. The arrival rates, distribution service capacity allowed f...

Packet networks are currently enabling the integration of traffic with a wide range of characteristics that extend from video traffic with stringent QoS requirements to the best-effort traffic requiring no guarantees. QoS guarantees can be provided in conventional packet networks by the use of proper packet scheduling algorithms. As a computer revolution, many scheduling algorithms have been pr...

Real-time disk I/O scheduling is extremely important to the performance improvement of the whole real-time system since the disk devices are the system’s bottleneck. To meet time constraints, some conventional algorithm, such as EDF, Least Slack Time First, Rate Monotonic, can be used to schedule disk I/O. However, these algorithms ignore the relative position of requested data on the disks, he...

This paper designs and analyzes the performance of a communication scheduler that cooperates with each other over the dual-channel wireless network, aiming at enhancing reliability and timeliness of time-sensitive applications on embedded devices. The proposed scheme consists of (1) evenly partitioning the stream set into two identical ones, (2) applying EDF (Earliest Deadline First) policy on ...

The multiprocessor partitioned scheduling of sporadic task systems is considered. The problem of obtaining feasible partitionings under both Earliest Deadline First (EDF) and Fixed Priority (FP) scheduling is represented as integer linear programs comprised of binary (zero / one) integer variables only.

In this paper, we validate the performance of Moody’s KMV EDF credit measures in its timeliness of default prediction, ability to discriminate good firms from bad firms, and accuracy of levels in three regions: North America, Europe, and Asia. We focus on the period 1996–2006 for most of our tests. Wherever possible, we compare the performance to that of other popular alternatives, such as agen...

The most frequency used goodness of fit tests are based on measuring the distance between the theoretical distribution function and the empirical distribution function (EDF), but presence of outliers influences these tests strongly. In this study, we propose a simple robust method for goodness of fit test by using the “Forward Search” (FS) method. The FS method is a powerful general method for ...

Real-time communication is important for time-critical multimedia applications. However, conventional real-time schedulers such as EDF (Earliest Deadline First) and RM (Rate Monotonic) are designed for task sets with sophisticated characteristics. They can perform well in the idea network with precise workloads. But, in a realistic network with shared bandwidth and unpredictable workloads, thei...

We present a real-time, Linux-based testbed called LITMUS, which we have developed for empirically evaluating multiprocessor real-time scheduling algorithms. We also present the results from such an evaluation, in which partitioned earliest-deadline-first (EDF) scheduling, preemptive and nonpreemptive global EDF scheduling, and two variants of the global PD Pfair algorithm were considered. The ...

In this paper, we consider a set of real-time periodic tasks where some tasks are preferably executed as soon as possible (ASAP) and others as late as possible (ALAP) while still meeting their deadlines. After introducing the idea of preference-oriented (PO) execution, we formally define the concept of PO-optimality. For fully-loaded systems (with 100% utilization), we first propose a PO-optima...