Continuous Monitoring in the Dynamic Sensor Field Model

Abstract

In this work we consider the problem of continuously monitoring a collection of data sets produced by sensors placed on mobile or static targets. Our computational model, the dynamic sensor field model, is an extension of the static sensor field model [3] allowing computation in the presence of mobility. The dynamicity comes from both the mobile communication devices and the data sensors. The mobility of devices is modeled by a dynamic communication graph depending on the position of the devices. Data mobility is due to measurements performed by sensing units that are not placed on fixed positions but attached to mobile agents or targets. Accordingly, we introduce two additional performance measures: the total traveled distance in a computational step and the gathering period.

We study the Continuous Monitoring problem providing bounds on performance for several protocols that differ in the use of mobility and the placement of the devices. Our objective is to analyze formally the computational resources needed to solve the Continuous Monitoring in a dynamic context. For doing so, we consider a particular scenario in which communication devices and data sensors move on top of a squared terrain discretized by a mobility grid. We also consider two scenarios, the static data setting in which sensors are placed at fixed but unknown positions and the dynamic data setting in which sensors are placed on dynamic targets and follow a passive mobility pattern.

Partially supported by the ICT Program of the European Union under contract number 215270 (FRONTS). The first, second and, fourth authors were also supported by the Spanish project TIN-2007-66523 (FORMALISM).