Analysis of a Fast LZ-Based Entropy Estimator for Mobility Data


Randomness in people's movements might serve to detect behavior anomalies. The concept of entropy can be used for this purpose, but its estimation is computational intensive, particularly when processing long movement histories. Moreover, disclosing such histories to third parties may violate user privacy. With a goal to keep the mobility data in the mobile device itself yet being able to measure randomness, we propose three fast entropy estimators based on Lempel-Ziv (LZ) prediction algorithms. We evaluated them with 95 movement histories of real users tracked during 9 months using GSM-based mobility data. The results show that the entropy tendencies of the approaches proposed in this work and those in the literature are the same as time evolves. Therefore, our proposed approach could potentially detect variations in the mobility patterns of the user with a lower computational cost. This allows to unveil shifts in the users mobility behavior without disclosing their sensible location data.

Meeting Name

2015 IEEE International Conference on Pervasive Computing and Communication Workshops, PerCom Workshops 2015 (2015: Mar. 23-27, St. Louis, MO)


Computer Science


This work was partially supported by the Spanish Ministries of Science and Innovation (through the CONSEQUENCE project, TEC2010-20572-C02-01/02) and of Economy and Competitiveness (through the EMRISCO project, TEC2013-47665-C4-4-R). The work of Das was partially supported by NSF grants IIS-1404673 and CNS-1404677.

Keywords and Phrases

Algorithms; Mobile devices; Random processes; Ubiquitous computing; Computational costs; Entropy estimator; Mobility behavior; Mobility datum; Mobility pattern; Movement history; Prediction algorithms; Third parties; Entropy

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Document Type

Article - Conference proceedings

Document Version


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© 2015 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Mar 2015