About me

I am currently pursuing my PhD in the department of Computer Science at the University of Illinois at Chicago (UIC). My primary research interest is in applying machine learning and data mining techniques to practical problems, particularly network and spatial applications. I have a BS in CS from Cornell University, and a MS in CS from DePaul University. I also love photography http://www.flickr.com/photos/cornellfool/.

I am an IGERT Fellow in UIC's Computational Transportation Science program, a new field that combines the cutting-edge of several fields in a multi-disciplinary effort to improve surface transportation systems. My PhD advisors are Peter Nelson (Computer Science) and Abolfazl (Kouros) Mohammadian (Civil and Materials Engineering). These problems include everything from real-time route planning based on traffic congestion patterns to multi-modal commuting options integrating live public transit location information.

My dissertation research involves algorithms and techniques for transfer learning of individual travel behavior across different geographies. The focus of this research will be leveraging transferrable aspects of travel behavior and patterns to reduce learning time, while also creating a richer model of the individual traveler. This research effort will identify algorithms and techniques needed to address the problem of learning and predicting the activity needs of an individual for anticipating their associated travel demands. The goal of this work is to enable intelligent travel applications by providing insight into an individual’s future travel plans and scheduling preferences. A major component of this effort is to provide this insight without compromising user privacy.

During my masters research with Dr. Bamshad Mobasher at DePaul University, we examined techniques for securing recommender systems. This project focuses on identifying weaknesses of existing recommendation algorithms, exploring more robust recommendation techniques, and limiting the impact of attacks on these systems.

Publications (BibTeX)

»	Mining Sequential Association Rules for Traveler Context Prediction Chad A. Williams, Abolfazl (Kouros) Mohammadian, Peter C. Nelson, and Sean T. Doherty To appear at The First International Workshop on Computational Transportation Science (IWCTS’08) Held at The International Conference on Mobile and Ubiquitous Systems: Networks and Services (MOBIQUITOUS 2008), Dublin, Ireland, July 2008
»	Defending Recommender Systems: Detection of Profile Injection Attacks Chad A. Williams, Bamshad Mobasher, and Robin Burke Journal of Service Oriented Computing and Applications, Vol. 1, No. 3, pp. 157-170, November 2007 [PDF]
»	Towards Trustworthy Recommender Systems: An Analysis of Attack Models and Algorithm Robustness Bamshad Mobasher, Robin Burke, Runa Bhaumik, and Chad Williams ACM Transactions on Internet Technology, Vol. 7, No. 4, pp. 23-60, October 2007 [PDF]
»	Classification Features for Attack Detection in Collaborative Recommender Systems Robin Burke, Bamshad Mobasher, Chad Williams, and Runa Bhaumik Proceedings of the ACM SIGKDD Conference on Knowledge Discovery and Data Mining (KDD'06) Philadelphia, Pennsylvania, August 2006 [PDF]
»	The Impact of Attack Profile Classification on the Robustness of Collaborative Recommendation Chad Williams, Runa Bhaumik, Robin Burke, and Bamshad Mobasher Proceedings of the 2006 WebKDD Workshop Held at KDD'2006, Philadelphia, Pennsylvania, August 2006 [PDF]
»	Detection of Obfuscated Attacks in Collaborative Recommender Systems Chad Williams, Bamshad Mobasher, Robin Burke, Jeff Sandvig, and Runa Bhaumik Proceedings of the ECAI’06 Workshop on Recommender Systems Held at the 17th European Conference on Artificial Intelligence (ECAI'06), Riva del Garda, Italy, August, 2006 [PDF]
»	Securing Collaborative Filtering Against Malicious Attacks Through Anomaly Detection Runa Bhaumik, Chad Williams, Bamshad Mobasher, and Robin Burke Proceedings of the 4th Workshop on Intelligent Techniques for Web Personalization (ITWP'06) Held at AAAI 2006, Boston, Massachusetts, July 2006. [PDF]
»	Analysis and Detection of Segment-Focused Attacks Against Collaborative Recommendation Bamshad Mobasher, Robin Burke, Chad Williams, and Runa Bhaumik Advances in Web Mining and Web Usage Analysis Olfa Nasraoui, Osmar R. Zaïane, Myra Spiliopoulou, Bamshad Mobasher, Brij Masand, and Philip S. Yu (eds.). Lecture Notes in Computer Science (Vol. 4198), Springer, 2006. [PDF]
»	Detecting Profile Injection Attacks in Collaborative Recommender Systems Robin Burke, Bamshad Mobasher, Chad Williams, and Runa Bhaumik Proceedings of the 8th IEEE Conference on E-Commerce Technology (CEC' 06) San Francisco, California, June 2006 [PDF] * Winner of best paper award
»	Evaluation of Profile Injection Attacks In Collaborative Recommender Systems Chad Williams, Runa Bhaumik, Jeff Sandvig, Bamshad Mobasher, and Robin Burke DePaul CTI Research Symposium / Midwest Software Engineering Conference (CTIRS/MSEC 2006) Chicago, Illinois, April 2006 [PDF] * Winner of best paper award
»	Segment-Based Injection Attacks against Collaborative Recommender Systems Robin Burke, Bamshad Mobasher, Runa Bhaumik, and Chad Williams Proceedings of the International Conference on Data Mining (ICDM 2005) Houston, Texas, November 2005 [PDF]
»	Collaborative Recommendation Vulnerability To Focused Bias Injection Attacks Robin Burke, Bamshad Mobasher, Runa Bhaumik, and Chad Williams Proceedings of the Workshop on Privacy and Security Aspects of Data Mining Held at ICDM'05, Houston, Texas, November 2005 [PDF]
»	Genetically Evolving Optimal Neural Networks Chad Williams Neural Networks and Expert Systems, The Institute of Chartered Financial Analysts of India (ICFAI), (to appear) [PDF]

Technical Reports

Mining Sequential Association Rules For Traveler Context Prediction
Chad A. Williams, Abolfazl Mohammadian, Peter C. Nelson, Sean T. Doherty

Department of Computer Science Technical Report No. 2007.08.01-001, University of Illinois at Chicago, 2007. [PDF]

Profile Injection Attack Detection for Securing Collaborative Recommender Systems
Chad Williams (Advisor: Bamshad Mobasher)

Masters Thesis, Department of Computer Science Technical Report No. 06-014, DePaul University, 2006. [PDF]