Unified Modeling and Reasoning in Constrained Outdoor and Indoor Spaces

Geographic information systems traditionally dealt with only outdoor spaces. In recent years, indoor spatial information systems have started to attract attention partly due to the increasing use of receptor devices (e.g., RFID readers or wireless sensor networks) in both outdoor and indoor spaces. Applications that employ these devices are expected to span uniformly and supply seamless functionality in both outdoor and indoor spaces. What makes this impossible is the current absence of a unified account of these two types of spaces both in terms of modeling and reasoning about the models. This paper presents a unified model of outdoor and indoor spaces and receptor deployments in these spaces. The model is expressive, flexible, and invariant to the segmentation of a space plan, and the receptor deployment policy. It is focused on partially constrained outdoor and indoor motion. On top of this model, clear representation of routes is honed, and a powerful route observability function is derived. The model facilitates probabilistic incorporation of receptor data through a probabilistic trajectory-toroute translator that enables performing high-level reasoning about points of potential traffic (over)load in outdoor and indoor spaces, so-called bottleneck points. An experimental evaluation corroborates the accuracy of the translator and the sensibleness of the reasoning, when applied to synthetic data, and importantly, to uncleansed, real-world receptor data obtained from tracking RFID-tagged flight baggage.