Capturing high-level conditions, using a Publish/Subscribe middleware, in sensor systems

In this paper we discuss state maintenance components (SMCs), which are used to capture high-level conditions in a state-based publish/subscribe (SPS) middleware. SMCs support temporal and spatial condition interrelationships, while using events received from a publish/subscribe (Pub/Sub) communication system. The SMC data structure is designed so as to enable SMC decompositions and distributions for effective load-balancing, localized processing, and information sharing. Our evaluation, using real sensor data in the context of a smart transportation system, demonstrates the expressiveness and the scalability of SMCs in the SPS middleware.