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Probabilistic Spatio-Temporal Retrieval in Smart Spaces

Publication Type : Journal Article

Publisher : Springer

Source : J. Ambient Intelligence and Humanized Computing, 5(3): 383-392, 2014, Springer.

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Campus : Amritapuri, Coimbatore, Kochi

School : School of Engineering, Department of Computer Science and Engineering, School of Business

Department : Computer Science, Department of Management

Year : 2014

Abstract : A ‘smart space’ is one that automatically identifies and tracks its occupants using unobtrusive biometric modalities such as face, gait, and voice in an unconstrained fashion. Information retrieval in a smart space is concerned with the location and movement of people over time. Towards this end, we abstract a smart space by a probabilistic state transition system in which each state records the probabilities of presence of individuals in various zones of the smart space. We carry out track-based reasoning on the states in order to determine more accurately the occupants of the smart space. This leads to a data model based upon an occupancy relation in which time is treated discretely, owing to the discrete nature of events, but probability is treated as a real-valued attribute. Using this data model, we show how to formulate a number of spatio-temporal queries, focusing on the computation of probabilities, an aspect that is novel to this model. We present queries both in SQL syntax and also in CLP(R), a constraint logic programming language (with reals) which facilitates succinct formulation of recursive queries. We show that the answers to certain queries are better displayed in a graphical manner, especially the movement tracks of occupants of the smart space. We also define query-dependent precision and recall metrics in order to quantify how well the model is able to answer various spatio-temporal queries. We show that a query-dependent metric gives significantly better results for a class of occupancy-related queries compared with query-independent metrics.

Cite this Research Publication : V. Menon, B. Jayaraman, V. Govindaraju, “Probabilistic Spatio-Temporal Retrieval in Smart Spaces”, Journal of Ambient Intelligence and Humanized Computing, Springer-Verlag Berlin Heidelberg, vol. 5, no. 3, pp. 383–392, 2014. DOI:

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