MiddleWhere: A Middleware for Location Awareness in Ubiquitous Computing Applications

Location awareness significantly enhances the functionality of ubiquitous computing services and applications, and enriches the way they interact with users and resources in the environment. Many different alternative or complementary location sensing technologies are available. However, these technologies give location information in different formats and with different resolution and confidence. In this paper we introduce “MiddleWhere” a distributed middleware infrastructure for location that separates applications from location detection technologies. MiddleWhere enables the fusion of different location sensing technologies and facilitates the incorporation of additional location technologies on the fly as they become available. MiddleWhere utilizes probabilistic reasoning techniques to resolve conflicts and deduce the location of people given different sensor data. Besides, it allows applications to determine various kinds of spatial relationships between mobile objects and their environment, which is key in enabling a strong coupling between the physical and virtual world, as emphasized by ubiquitous computing. We have integrated MiddleWhere with our ubiquitous computing infrastructure, and have verified its flexibility and usefulness by incorporating various location sensing technologies and building a number of location-sensitive applications on top of it.