Research

I am a Postdoctoral Research Fellow in Data Science at the University of Exeter. My primary areas of interest include network science, human mobility patterns, and computational social science. My research focuses on quantifying, understanding, and exploiting spatiotemporal structure in complex systems, ranging from social networks to technological ones.

I completed my PhD in the School of Computer Science & InformaticsCardiff University.  My supervisors were Roger Whitaker and Stuart Allen. During this time my research was funded by the SOCIALNETS project, the RECOGNITION project, and the Cardiff School of Computer Science & Informatics (CS&I).

My thesis, titled "Periodic patterns in human mobility", explores the prevalence of routine in human mobility and introduces techniques for automatically extracting periodic patterns in visits (person-at-place events) and encounters (person-meets-person events). These techniques borrow in part from the concept of neural synchrony in the field of computational neuroscience. Furthermore, the thesis investigates the existence of broader-scale periodic encounter behaviour, extending the conventional definition of community into the temporal and periodic domain. Through the use of empirical mobility datasets collected from urban transport systems, location-based networks (specifically, Foursquare), mobile phone use, and WLAN networks, the thesis explores periodicity and routine in real-world human behaviour.

Previously, I was part of the Cardiff Distributed and Scientific Computing research group and co-founder and seminar coordinator of the Mobile and Social Computing (MobiSoc) research forum. I have also been a member of the Networked Systems and Data Science Lab at the University of Birmingham and visiting member of the Geospatial Analytics and Computing group at UCL Geography.

PhD Thesis

Periodic patterns in human mobility
M.J. Williams, Cardiff University, 2013.
Examiners:
David Hales (The Open University, UK & EPFL, Switzerland)
Cecilia Mascolo (University of Cambridge, UK)
[E-Print on ORCA]

Preprints and Articles In Submission

Peer-Reviewed Journal Articles

There and Back Again: Detecting Regularity in Human Encounter Communities
M.J. Williams, R.M. Whitaker, S.M. Allen. 2016
In IEEE Transactions on Mobile Computing, 2016. [DOI: 10.1109/TMC.2016.2599169]

Spatio-Temporal Networks: Reachability, Centrality, and Robustness
M.J. Williams, M. Musolesi
In Royal Society Open Science, 3, 160196, 2016. [DOI: 10.1098/rsos.160196]
[arXiv Preprint arXiv:1506.00627 ] [NetSci 2015 Slides]

Decentralised detection of periodic encounter communities in opportunistic networks
M.J. Williams, R.M. Whitaker, S.M. Allen
In Ad Hoc Networks, vol. 10, iss. 8, pp. 1544-1556, 2012. DOI: 10.1016/j.adhoc.2011.07.008.
[Preprint PDF 1MB]

Book Chapters

Mining Foursquare as a platform for computational social science
M.J. Williams, M.J. Chorley
In The SAGE Handbook of Social Media Research Methods (editors: L. Sloan, A. Quan-Haase), 2016 (To Appear).

Peer-Reviewed Conference and Workshop Papers

Pub crawling at scale: Tapping Untappd to explore social drinking
M.J. Chorley, L. Rossi, G. Tyson, M.J. Williams   [alpha order]
In Proc. 2016 AAAI International Conference on Web and Social Media (ICWSM), May 2016.
[PDF Postprint 1MB] [Proc. AAAI]

Measuring urban social diversity using interconnected geo-social networks
D. Hristova, M.J. Williams, M. Musolesi, P. Panzarasa, C. Mascolo
In Proc. International World Wide Web Conference (WWW), April 2016. DOI: 10.1145/2872427.2883065

Different news for different views: Political news-sharing communities on social media through the UK General Election in 2015
M.J. Williams, I. Ciorianu, H.T.P. Williams
In Proc. International Workshop on News and Public Opinion (NECO), May 2016.
[Proc. AAAI] [Slides SpeakerDeck]

Privacy and the city: User identification and location semantics in location-based social networks
L. Rossi, M.J. Williams, C. Stich, M. Musolesi
In Proc. 2015 AAAI International Conference on Web and Social Media (ICWSM), May 2015.
[Preprint on arXiv] [Proc. AAAI]

Measuring individual regularity in human visiting patterns
M.J. Williams, R.M. Whitaker, S.M. Allen
In Proc. 2012 ASE/IEEE International Conference on Social Computing (SocialCom), Sept 2012. DOI: 10.1109/SocialCom-PASSAT.2012.93.
[Slides PDF 2MB] [Slides SpeakerDeck] [Paper PDF 1MB]

You are where you eat: Foursquare checkins as indicators of human mobility and behaviour
G. Colombo, M.J. Chorley, M.J. Williams, S.M. Allen, R.M. Whitaker
In Proc. International Workshop on the Impact of Human Mobility in Pervasive Systems and Applications (PerMoby) (held in conjunction with PerCom 2012), Mar 2012. DOI: 10.1109/PerComW.2012.6197483.
[Slides PDF 4MB] [Slides SpeakerDeck] [Paper PDF 1MB]

Checking out checking in: Observations on Foursquare usage patterns
M.J. Chorley, G. Colombo, M.J. Williams, S.M. Allen, R.M. Whitaker
In Proc. International Workshop on Finding Patterns of Human Behaviors in Network and Mobility Data (NEMO) (held in conjunction with ECML-PKDD2011), Sept 2011.
[Slides PDF 5MB] [Slides SpeakerDeck] [Preprint PDF 5MB]

Community Service

Reviewer – Journals

IEEE Transactions on Mobile Computing
IEEE Transactions on Big Data

Program Committee Member

ICWSM – 10th International AAAI Conference on Weblogs and Social Media, 2016.
UIC – 12th IEEE Conference on Ubiquitous Intelligence and Computing, 2015.
ICWSM – 9th International AAAI Conference on Weblogs and Social Media, 2015.

Reviewer – Conferences and Workshops

WebSci – ACM Conference on Web Science, 2015.
CHI, Works-In-Progress track – SIGCHI Conference on Human Factors in Computing Systems (CHI), 2015.
Mobiquitous – 11th International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services, 2014.
CSAR – Workshop on Collective Social Awareness and Relevance at the 3rd International Conference on Social Computing and its Applications (SCA), 2013.
HICSS – 43rd Hawaii International Conference on System Sciences, 2010.

Research Talks and Posters

NetSci 2015 Talk
Measuring the robustness of real-world spatio-temporal networks
June 2015. Research talk. International School and Conference on Network Science (NetSci), in Zaragoza, Spain.
[Slides SpeakerDeck]

VLunch (Cardiff CS&I Vision Group) Seminar Talk
Periodic patterns in human mobility
Oct 2013. Research talk.
[Slides PDF 7MB] [Slides SpeakerDeck]

Cardiff University Distinguished Lectures in Social Computing Poster Session
Measuring regularity in the visiting patterns of Foursquare users
Dec 2011.  Poster presentation.
[Poster PDF 4MB]

Cardiff School of Computer Science & Informatics Research Retreat 2011
Periodic patterns in human encounters
May 2011. Research talk. Ignite format. Award: school prize for best third-year research presentation.
[Slides PDF 7MB] [Slides SpeakerDeck]

Cardiff School of Computer Science & Informatics Poster Day 2011
Decentralised periodic encounter community detection
Jan 2011. Poster presentation. Award: student prize for best third-year research poster.
[Poster PDF 4MB]

VLunch (Cardiff CS&I Vision Group) Seminar Talk
Decentralised periodic encounter community detection
May 2010. Research talk.
[Slides PDF 2MB] [Slides SpeakerDeck]

Cardiff School of Computer Science & Informatics Research Retreat 2010
Decentralised periodic encounter community detection
May 2010. Research talk. Award: school prize for best second-year research presentation.

Cardiff School of Computer Science & Informatics Poster Day 2010
Decentralised periodic encounter community detection
Jan 2010. Poster presentation. Awards: school and student prizes for best second-year research poster.
[Poster PDF 3MB]

Cardiff School of Computer Science & Informatics Research Retreat 2009
Contact prediction for content sharing in human mobile peer-to-peer networks
May 2009. Research talk. Award: school prize for best first-year research presentation.

Cardiff School of Computer Science & Informatics Poster Day 2009
Predicting future contacts in mobile peer-to-peer networks
Jan 2009. Poster presentation. Awards: school and student prizes for best first-year research poster.
[Poster PDF 4MB]