The main challenges in model checking real-time Java programs are scalability and compliance with the Real-time Specification for Java (RTSJ) semantics. A model checker for RTSJ programs has to support the notion of thread periods and priority-preemptive scheduling as well as understand the region-based memory model introduced by the specification. We present the RJ model checker for multi-thre...

This paper presents an adaptive reservation protocol called Centralized Adaptive Reservation (CAR) for supporting voice and data communications over a wireless ATM LAN. The protocol has two novel features, which may also be applied in other wireless LANs. First, with the aim of enhancing access efficiency, the access probability of the voice terminals is varied dynamically based on the predicte...

This paper considers a novel queueing model called the Multi-Priority Dual Queue (MPDQ), which was introduced and analyzed in Bedford and Zeephongsekul [1, 2]. The MPDQ consists of two queues with a finite buffer, the primary and the secondary queue with the additional feature of a priority scheme to assist with congestion control and meeting Quality of Service ( ) QoS objectives for differenti...

For lack of optical random access memory, optical fiber delay line (FDL) is currently the only technology to implement optical buffering. Feed-forward and feedback are two types of FDL structures in optical buffering, both have advantages and disadvantages. In this paper, we present a novel architecture for WDM optical packet switches with an effective hybrid FDL buffering that combines the mer...

Increasing complexity of today’s WSAN applications can rapidly result in reduced real-time capabilities of the underlying sensor nodes. Using preemptive operating systems is one way to retain acceptable reactivity within highly dynamic environments but commonly leads to severe resource management problems. We outline our dynamic hinting approach for maintaining high system reactivity by efficie...

The embedded systems work on real time operating systems (ERTOS). There are many CPU scheduling policies in general operating systems out of which ERTOS most commonly follow the priority and round robin scheduling. The aim of this research work is to evaluate performance of these scheduling policies. Simulation is adopted as tool to find the best policy that can be implemented to boost the perf...

Abstract—This report presents our recent efforts to close the gap between the state-of-the-art homogeneous (or identical) multiprocessor and uniprocessor schedulability analyses in the context of resource sharing. Although many multiprocessor resource sharing protocols have been proposed, their impact on the schedulability of real-time tasks is largely ignored in most existing literature. Recen...

A real time distributed computing has heterogeneously networked computers to solve a single problem. So coordination of activities among computers is a complex task and deadlines make more complex. The performances depend on many factors such as traffic workloads, database system architecture, underlying processors, disks speeds, etc. Simulation study have been performed to analyze the performa...

We present first constant performance guarantees for preemptive stochastic scheduling to minimize the sum of weighted completion times. For scheduling jobs with release dates on identical parallel machines we derive policies with a guaranteed performance ratio of 2 which matches the currently best known result for the corresponding deterministic online problem. Our policies apply to the recentl...

We consider a multi-server non-preemptive queue with high and low priority customers, and a decision maker who decides when waiting customers may enter service. The goal is to minimize the mean waiting time for high-priority customers while keeping the queue stable. We use a linear programming approach to find and evaluate the performance of an asymptotically optimal policy in the setting of ex...