Event-Based Mobility Modeling and Analysis

Abstract

Mobility is a critical issue that must be considered during the modeling and analyzing of a mobile system. At a high abstract level, event-based models can directly specify a mobile system without the introduction of additional mechanisms. In this article, we first propose two types of special events, entering and exiting an ambient, as movement events. Next, based on the movement events, we introduce the notion of a movement path and propose a feasible movement criterion (deciding whether a given movement path of a mobile object (agent) is feasible or not in terms of spatiotemporal topological relationships of ambients). Then, we investigate how a message movement--based communication model represents synchronous communication, asynchronous communication, and broadcast communication in a unified way. Finally, we use movement event sequences to discuss the exclusivity of ambients (an ambient only allows one mobile object to occupy (enter) it at any moment) and show that a priority scheduling control policy can guarantee exclusivity. Accordingly, we propose a correct movement criterion—that is, a correct movement path is feasible and satisfies the exclusivity of ambients. Case studies demonstrate these results.

Schedulability analysis for real-time mobile systems (S)

“…In fact, it is enough for us to only use the two movement events (entering and exiting events) for specifying the mobility in a mobile system. For more information, please refer to our previous work [4].…”

“…To solve the problem, it is necessary for a new scheduling policy to control the whole mobile system [1], [4]. Jiang et Corresponding author: Jian-Min Jiang (jjm@fjnu.edu.cn).…”

“…al. [4] have proposed more fine-grained event-based scheduling instead of task scheduling. An event is generally the occurrence of an action or activity.…”

“…A complex scheduling problem cannot be decomposed into independent tasks, but it can be divided into sub-problems of event-based scheduling. Though Jiang et al [4] have discussed event-based scheduling, such event-based scheduling does not consider real-time scheduling controls, especially the scheduling in realtime mobile systems.…”

“…To investigate the scheduling in real-time mobile systems, we must model real-time mobile systems. We extend the dependency structure model [4], [5] and add the time modeling power to it. Such a model is called a time dependency structure, which can conveniently specify the timing constraints and mobility of real-time mobile systems.…”