Demo Abstract: GSN, Quick and Simple Sensor Network Deployment Ali Salehi School of Computer and Communication Sciences Ecole Polytechnique F´ ed´ erale de Lausanne Switzerland firstname.lastname@epfl.ch Karl Aberer School of Computer and Communication Sciences Ecole Polytechnique F´ ed´ erale de Lausanne Switzerland firstname.lastname@epfl.ch Abstract— Wireless sensor and actuator networks are an emerging computer class based on a new platform, networking structure, and interface that enable novel, low cost and high volume applications. One of the main obstacles in adaption of the sensor networks is the lack of standardization and the continuous inflow of novel sensor network technologies which have made the sensor network deployment the main factor of manpower consumption. To address these problems we developed the Global Sensor Networks (GSN) middleware with the aims of rapid and simple deployment of a wide range of sensor network technologies, providing flexible integration and discovery of sensor networks, enabling addition of new platforms quickly, and dynamically adaption of the system configuration during operation. In this paper we provide a brief overview of GSN with the focus on automated wireless sensor network deployment. GSN is available for download at http://gsn.sourceforge.net. I. I NTRODUCTION AND MOTIVATION The emergence of wireless sensor networks as one of the dominant technology in the coming decades has posed numerous unique challenges to researchers. These networks are designed to be composed of hundreds, and potentially thousands of small smart sensor nodes (called motes), func- tioning autonomously, and in many cases, without access to renewable energy resources. While the set of defined research problems in the wireless sensor networks are diverse, we focus on practical aspects of sensor network deployment. As organizations have begun working with the wireless sensor networks, two significant obstacles have emerged: deploying wireless sensor networks is extremely time-consuming not only because of the complexity of creating the software that manages the networks and their components but also the heterogeneity introduced due to different (an sometimes conflicting) application requirements. These challenges are so significant that they have slowed deployment plans to a crawl, and have considerably tempered initial excitement about wireless sensor network technology. To address these problems we developed the Global Sensor Networks (GSN) middleware which supports rapid and simple deployment of a wide range of wireless sensor network tech- nologies, provides flexible integration and discovery of sensor networks in addition to the common data stream processing requirements off the shelf. GSN offers virtual sensors as a simple and powerful abstraction, which enables the user to declaratively specify XML-based deployment descriptors in combination with the possibility to integrate sensor network data through plain SQL queries over local and remote sensor data sources. In the GSN we follow the standard model of sensor network deployment in which a sensor network can have one or more base computers, which are dedicated to perform expensive data mining operations in addition to disseminating the outputs (processed or raw) to the interested users. GSN is designed to be used on the base computer. GSN looks at the sensor network as a black-box which can produce sensor data and optionally consume control messages. Depending on hardware and software restrictions on the sensor networks, the con- nection between the base computer and the sensor network can be either unidirectional or bidirectional. For instance, a sensor network of RFID readers only produces a stream of string values representing the TagID and their contents (hence unidirectional) while a sensor network programmed to use TinyDB not only can produce the aggregated sensor readings but also can consume TinySQL queries (hence bidirectional). The reason for this separation is to use the in-network pro- cessing capabilities of sensor networks as much as possible. II. GSN AND VIRTUAL SENSORS The key abstraction in GSN is the virtual sensor. Virtual sensors abstract from implementation details of access to the sensor network and correspond either to data streams received directly from sensors or derived from other virtual sensors accessible through the network (thus a chain of virtual sensors). A virtual sensor can be any kind of data producer and/or consumer, for example, a real sensor, a wireless camera, a desktop computer, a cell phone, or any combination of virtual sensors. A virtual sensor may have any number of input streams (called sources) and produces exactly one output data stream based on the input data streams and arbitrary local processing. The virtual sensor descriptor (VSD), which is a XML file, provides all the necessary information required for deploying and using the virtual sensors, such as the meta-data used for identification and discovery, the structure and properties of the produced data streams, a declarative SQL-based specification of the data stream processing and filtering and finally the functional properties related to stream