For example, in the specific case of an environmental monitoring application, some nodes may be equipped with temperature sensors, other nodes with humidity sensors, but all bear similar communication devices and processing capabilities; it should be noted, however, that heterogeneous networks have been conceived as well, where, e.g., a large number of nodes perform sensing, a few expensive nodes provide data fusion and filtering, and the node differences in terms of computational capabilities and links are exploited for networking purposes .As will be made clearer in the following sections, these three aspects represent canonical issues that are kept in focus during the design of the (department-wide) testbed, with the implicit aim of being modularly extensible to wider (city-scale) scenarios.
WSNs can offer access to an unprecedented quality and quantity of information that can deeply change our ability to sense and control the environment. The fields of application of WSNs cover a wide variety:home automation (domotics) and energy management systems [3�C6]: devoted to the monitoring and control of the environment of private homes for the comfort and security of their residents; this, especially in large buildings, may also include the management of their energy resources;assistive domotics , i.e.
, home automation for the elderly and disabled, where the general features of home automation are ancillary to those implied by regularly monitoring specific physiological and medical parameters of the residents;industrial automation : aiming more specifically at the analysis and control of the environment (in terms of temperature, humidity, light, but also chemicals, vapors, radiation) in work places presenting critical issues of potential danger, such as, to cite a few, greenhouses, AV-951 mechanical laboratories, chemical plants and refineries, foundries; this category also includes simpler issues such as the management and conservation of goods in large stores and warehouses;surveillance : in terms of networks of cameras, microphones, access control devices, intrusion detection systems, and so forth. The integration and fusion of the information provided by single devices, using different technologies and from different physical points of view, allow a more complete (if not exhaustive) reconstruction of the whole scene of interest.