Uncertainty Reduction in Location-Based Retrieval of Georeferenced Web Resources by Moving Users

This paper describes Matrioshka GeoScent, a prototypal system able to answer uncertain location based queries submitted by a moving user. The user searches for georeferenced resources on the web, by entering topics keywords, and specify the uncertain spatio temporal condition on their location by specifying a time span. This last condition is a spatio-temporal constraint on the resources distance from the estimated user’s location reached in the given time span (e.g. “restaurants close to my possible location reached in half an hour”). Queries are evaluated by modeling the user context, i.e., the underlying road network, the last tracked positions and direction, as well as other factors that can influence the speed such as the type of transport, the type of road, the day, the weather conditions. The system, by modeling the user context, determines the possible user locations at a specified time instant and retrieves the web pages describing the desired georeferenced resources, ranked combining their route distance from the estimated possible user location and their topics relevance.