High Level Definition of Event-Based Applications for Pervasive Systems

Abstract

Within pervasive intelligent environments, Wireless Sensor Networks (WSNs) will surround and serve us at any place and any time. A proper usability is considered essential for WSNs supporting real life applications. With this chapter, we aim at ease of use for specifying new applications that have to autonomously cope with expected and unexpected heterogeneity, sudden failures, and energy efficiency. Starting with general design criteria for applications in WSNs, we created a user-centric design flow for pervasive applications. The design flow provides very high abstraction and user guidance to refrain the user from implementation-, deployment- and hardware-details including heterogeneity of the available sensor nodes. Automatic event configuration is accomplished by using a flexible Event Specification Language (ESL) and Event Decision Trees (EDTs) for distributed detection and determination of real world phenomena. EDTs autonomously adapt to heterogeneous availability of sensing capabilities by pruning and subscription to other nodes for missing information. We present one of numerous simulated scenarios proving the robustness and energy efficiency with regard to the required network communications. From these, we learned how to deduce appropriate bounds for configuration of collaboration region and leasing time by asking for expected properties of the phenomena to be detected.