Logical Sensor Network: An Abstraction of Sensor Data Processing over Multidomain Sensor Network

This paper focuses on a sensor network virtualization over multidomain sensor network and proposes an abstraction called “logical sensor network (LSN)” for sensor data processing. In the proposed abstraction, processing is a directed acyclic graph that consists of nodes and streams, which represents a small data processor and communication rules between them, respectively. We have added a notion of a trigger to this graph. A trigger represents a timing of the process execution. We have implemented the middleware named LSN-Middle to run a virtualized sensor network and proved its feasibility. 1. Introduction In a future where sensor networks are ubiquitously around us, applications should interact with multiple sensor networks that belong to different domains. Many efforts to make a platform that provides applications a transparent access to sensor data from existing sensor networks with different domains have been made [1–8]. We call this type of platforms “multidomain sensor network (MDSN).” Sensor networks in MDSN include various types of hardware, are organized by different institutions, and are distributed over the world. Utilizing MDSN from applications has two undesirable features that are (1) sensor heterogeneity and (2) raw sensor data delivery. This means applications can only receive raw sensor data with heterogeneous data units and they are responsible for the data translation or the data preprocessing phases. This is caused by a feature that programmers cannot neither configure nor program the sensor networks which consist MDSN. Thus, we consider that an application development over MDSN will be more complicated than the development over a single homogeneous sensor network on which an application programmer has a full configurability and programmability. For these undesirable features of MDSN, a virtualization of a sensor network can be an effective solution. Sensor network virtualization over MDSN can provide a dedicated sensor network to each application as shown in Figure 1. This figure illustrates application and physical, multidomain and virtualized sensor network. MDSN aggregates physical sensor networks that have been installed for specific purposes [9–13]. And virtualized sensor networks recompose MDSN and create sensor networks for arbitrary applications with arbitrary specifications. Many researchers have been investigating middleware which offers applications to create a virtualized sensor network [14–17]. The middleware allows an application to define a virtualized sensor network. The application can be developed and operated as