PERLA: A DECLARATIVE LANGUAGE AND MIDDLEWARE FOR PERVASIVE SYSTEMS?
Fabio Alberto Schreiber, Romolo Camplani, M. Fortunato, Marco Marelli, F. A. Schreiber, R. Camplani, M. Fortunato, M. Marelli · 2008
Abstract. The system aims at managing, with a unique language, data sampled from different nodes of a pervasive system, providing them to the final user. It is composed of three elements: the nodes are heteroge-neous devices equipped with sensors, which collect data and send them through the network managed by the middleware; PERLA (PERva-sive LAnguage) is the SQL like language used to query logical objects, that are abstractions of the nodes; themiddleware is a stack of software layers providing an implementation of the logical object abstraction. An-swers to the queries take into account the context the system operates within, in order to provide the user with data appropriate to different environmental conditions. 1 The Language PERLA is a language which allows the user to interact with logical objects by wrapping physical devices [1]. It is worth to notice that a logical object can abstract both a single sensor node and a set of devices (e.g. a whole WSN). The