Dynamic Detection and Tracking of Composite Events in Wireless Sensor Networks

In questa tesi si presenta un sistema (MaD-WiSe) per la gestione efficiente di dati in reti di sensori senza fili (WSN) in scenari statici, e si forniscono diverse tecniche di ottimizzazione validate da risultati sperimentali su una rete di sensori reale. Si presenta inoltre un nuovo linguaggio dichiarativo (EQL) per esprimere eventi compositi da rilevare e tracciare in modo dinamico e autonomo e si fornisce uno schema di implementazione e un simulatore per la valutazione delle performance

Modeling Detection and Tracking of Complex Events in Wireless Sensor Networks

Wireless Sensor Networks (WSN) are widely used to monitor physical environments and recent developments have proposed to express the data gathering tasks of a WSN by means of a query language. In this thesis we formalize the notion of network-event in a WSN and we propose a query language to manage and interact in its detection, tracking and classification. A general event is a natural phenomenon characterized by similar environmental conditions and it is subjected to both temporal and spatial conditions. The network-event identifies the same phenomenon but seen through the sensing ability (temperature, noise, humidity) of a WSN. To manage the network-event and gather its data we propose a new query language (QL) that allows us to keep an high level of abstraction in moving the query subject from the physical sensors, to the natural phenomenon that occurs in the WSN. With a query bounded to an event we can then realize a mobile-query system able to follow the movements of an event in the network. Traditional approaches assume that a query, or more precisely its network task, lives and is executed on a specific sensor: we have instead in mind to let it to move (or clone) around the sensors involved in the same event. The aim of this thesis is the formalization of a network-event and the definition of a query language to deal with network-event based system. Furthermore we propose the guidelines, by means of running example, to implement such kind of system and we show its advantage comparing to the previous ones