Mobile Intelligence

25.1 INTRODUCTION

The wireless sensor network (WSN) is an application-specific networking framework, which is widely used in battlefields, disaster areas, and nuclear power plants for environmental monitoring, target detection, event tracking, security surveillance, and so on. Among these applications, tracking is one of the most significant tasks especially for the critical scenario, in which a user intends to realize the event in the region of interest. In general, a sensor in WSNs needs to continuously sense the attributes of the event. Once detecting the event, the sensor conveys the sensor data either toward the sink or to the data-centric sensors for external storage. In WSNs, tracking is to achieve two goals: target tracking and event boundary determination. The former focuses on identifying one or multiple static or mobile targets, whereas the latter concentrates on recognizing the edge of the event of interest by using the sensors near the event boundary.

The majority of previous work in terms of tracking not only considers a wireless homogeneous sensor network, in which only one type of sensors equipped with the same sensing units are deployed but also focuses on the event formed by only one attribute. If an event is composed of multiple attributes, the existing approaches are unsuitable for the event tracking because any one of the attributes cannot be perceived by only one type of sensor. Thus, different types of sensors with various sensing units are necessary for ...