A Semantic Location Service for Pervasive Grids

In the last decade, Grid Computing and Pervasive Computing paradigms have emerged and rapidly affirmed. These two worlds, however, can no longer be separated islands. As a matter of fact, traditional grids are moving towards Pervasive Grid environments and, as a result, they benefit from both grid and mobile technologies. In particular, a key feature of the Pervasive Computing paradigm, like the location-awareness, can be used to enhance the QoS of existing Grid services, that is Pervasive Grids should customize services access depending on mobile objects locations. But, in these environments, such as in the Pervasive environments, different types of positioning systems can be used to determine mobile objects locations and each of them produces location information with a specific format and granularity. This paper presents a location service that locates active mobile objects, such as Wi-Fi enabled devices and RFID tagged entities, in Pervasive Grids. The key feature of the service is the use of ontologies and rules to define a uniform, unambiguous and well-defined model for the location information, independently from the particular positioning system. Moreover, the location service performs logic and reasoning mechanisms both for providing physical and semantic locations of mobile objects and for giving the location information with the finest granularity when a mobile object is located by more than one positioning system. The service has been developed at the top of the standard OGSA architecture.