Proceedings Article10.1145/941079.941085
Spatio-temporal data reduction with deterministic error bounds
Hu Cao,Ouri Wolfson,Goce Trajcevski +2 more
- 19 Sep 2003
- pp 33-42
TL;DR: It is argued that when cellular phones and Personal Digital Assistants become location-aware, the size of the spatio-temporal information generated may prohibit efficient processing, and proposes to adopt a technique studied in computer graphics, namely line-simplification, as an approximation technique to solve this problem.
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Abstract: A common way of storing spatio-temporalinformation about mobile devices is in the form of a 3D (2D geography + time) trajectory. We argue that when cellular phones and Personal Digital Assistants become location-aware, the size of the spatio-temporal information generated may prohibit efficient processing. We propose to adopt a technique studied in computer graphics, namely line-simplification, as an approximation technique to solve this problem. Line simplification uses a distance function in producing the trajectory approximation. We postulate the desiderata for such a distance: it should be sound, namely the error of the answers to spatio-temporal queries must be bounded. We analyze several distances, and prove that some are sound in this sense for some types of queries, while others are not. Interestingly, not a single distance analyzed proves to be sound for all the common spatio-temporal queries, and therefore multi-distance line-simplification is introduced and analyzed. Then we propose an aging mechanism which gradually shrinks the size of the trajectories as time progresses. Finally, we analyze experimentally the effectiveness of line-simplification in reducing the size of a trajectories database.
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Citations
Managing uncertainty in moving objects databases
TL;DR: This article proposes to model an uncertain trajectory as a three-dimensional (3D) cylindrical body and introduces a set of novel but natural spatio-temporal operators which capture the uncertainty and are used to express spatio/temporal range queries.
346
Spatio-temporal compression of trajectories in road networks
TL;DR: An extended data model and a network partitioning algorithm into long paths to increase the compression rates for the same error bound are proposed and integrated with the state-of-the-art Douglas-Peucker compression algorithm to obtain a new technique to compress road network trajectory data with deterministic error bounds.
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Nonmaterialized motion information in transport networks
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- 05 Jan 2005
TL;DR: This work examines an alternative representation of motion in 3D space-time, called a nonmaterialized trajectory, which addresses both problems by taking advantage of the a priori knowledge that the motion occurs on a transport network.
Efficient real-time trajectory tracking
Ralph Lange,Frank Dürr,Kurt Rothermel +2 more
- 01 Oct 2011
TL;DR: This work proposes a family of tracking protocols that allow trading the communication cost and the amount of trajectory data stored at a MOD off against the spatial accuracy, and presents an effective compression technique to optimize the reduction performance of real-time line simplification in general.
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Remote real-time trajectory simplification
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- 09 Mar 2009
TL;DR: Moving objects databases (MODs) have been proposed for managing trajectory data, an important kind of information for pervasive applications, and generally stores simplified trajectories only.
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