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SARAH RAJTMAJER (PI)

Sarah Rajtmajer is an associate professor in the College of Information Sciences and Technology and research associate in the Rock Ethics Institute at Penn State. Her research integrates machine learning, AI and hybrid human-AI systems to understand how information encodes values like accuracy, objectivity, and privacy, and the trade-offs involved in managing healthy information ecosystems.

Before joining the Penn State faculty, she served as a consultant to the Defense and Intelligence communities on scientific programs for national security, with specific focus on initiatives in big data and computational social science. Prior to her work in consulting, Dr. Rajtmajer was an Intelligence Community Postdoctoral Research Fellow at the Applied Research Laboratory and a Postdoctoral Scholar in the Department of Mathematics at Penn State. Dr. Rajtmajer has a PhD in Mathematics from the University of Zagreb, Croatia, and a BA in Mathematics from Columbia University.

 

SAI DILEEP KONERU (PhD student) Sai is a fifth year PhD student in the College of Information Sciences and Technology at Penn State. Prior to joining the College, Sai was a Masters students in the Department of Industrial Engineering. Sai's work is in NLP, developing novel methods to combine text and underlying network structure to understand scholarly output. **update! Sai defended his PhD Dissertation in Feb 2026! Sai is now a scientist at PNNL. 

 

XINYU WANG (PhD student) Xinyu (Ginny) is a fifth year PhD student in the College of Information Sciences and Technology at Penn State and recipient of the College's prestigious University Graduate Fellowship. She holds a Masters of Engineering from University of California at Berkeley and a Bachelors in Industrial Engineering from University of Illinois at Urbana-Champaign. Ginny's work uses machine learning to understand the role of narrative in misinformation. **update! Ginny defended her PhD Dissertation in April 2026! Ginny is now a data scientist at Meta.

 

TATIANA CHAKRAVORTI (PhD student) Tatiana is a fifth year PhD student in the College of Information Sciences and Technology at Penn State. She holds Bachelor, Masters and Doctoral degrees in Electronics and Engineering Communication. Tatiana has prior work on machine learning applications for smart technologies and previously worked as an assistant professor at KL University in India. At Penn State, Tatiana is working on hybrid human-AI systems to evaluate information integrity. **update! Tatiana defended her PhD Dissertation in May 2026! Tatiana is starting a postdoc at the University of Alabama.

 

YINGFAN ZHOU (PhD student) Yingfan is a fourth year PhD student in the College of Information Sciences and Technology at Penn State. She holds a Masters of Information Science from University of Pittsburgh. Yingfan’s work constructs and applies computational methods to explore toxicity in online communities.

 

JIAYI LI (PhD student) Jiayi is a third year PhD student. Jiayi has a Bachelor degree from Penn State's College of IST. She is interested in machine learning and NLP. She is currently using these methods to study user privacy in online social networks.

 

QIAN MA (PhD student) Qian is a second year PhD student in the College of IST. ​ Qian holds a Master’s degree in Information Assurance from the University of Delaware. His research focuses on privacy preservation in AI-driven systems and social networking platforms. Master’s degree in Information Assurance from the University of Delaware. His research focuses on privacy preservation in AI-driven systems and social networking platforms. Before starting his PhD, Qian worked in the mobile internet industry for over ten years.

 

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DEAVON PODUSZLO (Masters student)

SNEHA ARYA (Undergraduate student)

EMMA ROSE CARPENETTI (Undergraduate student; Schreyer Honors College)

ZACK RANJAN (Undergraduate student)

CARISSA YU (Undergraduate student; Schreyer Honors College)

  1. A. Squicciarini, S. Rajtmajer, N. Zannone. Multi-Party Access Control: Requirements, State of the Art and Open Challenges. Symposium on Access Control Models and Technologies (SACMAT). June 2018.

  2. N. Gilbert, R. Bernier, V. Calhoun, E. Brenner, E. Grossner, S. Rajtmajer and F. Hillary. Diminished Neural Network Dynamics after Moderate and Severe Traumatic Brain Injury. PLoS One, June 2018. 

  3. J. Semonsen, C. Griffin, A. Squicciarini, S. Rajtmajer. Opinion Dynamics in the Presence of Increasing Agreement Pressure. IEEE Transactions on Cybernetics. February 2018. 

  4. S. Rajtmajer, A. Squicciarini, J. Such, J. Semonsen, and A. Belmonte. An Ultimatum Game Model for the Evolution of Privacy in Jointly Managed Content. Conference on Decision and Game Theory for Security (GAMESEC), October 2017.

  5. C. Qiu, A. Squicciarini, S. Rajtmajer and J. Caverlee. Dynamic Contract Design for Heterogeneous Workers in Crowdsourcing for Quality Control. International Conference on Digital Society (IEEE ICDS), July 2017.

  6. A. Squicciarini, S. Rajtmajer and C. Griffin. Positive and Negative Behavioral Analysis in Social Networks. WIRE Data Mining and Knowledge Discovery, May 2017.

  7. J. Semonsen, C. Griffin, A. Squicciarini, and S. Rajtmajer. Consensus on Social Graphs under Increasing Peer Pressure (Extended Abstract). International Conference on Autonomous Agents and Multiagent Systems (AAMAS), May 2017.

  8. H. Zhong, H. Li, A. Squicciarini, S. Rajtmajer, C. Griffin, D. Miller and C. Caragea. Content- Driven Detection of Cyberbullying on the Instagram Social Network. International Conference on Artificial Intelligence (IJCAI), July 2016.

  9. C. Liao, A. Squicciarini, C. Griffin and S. Rajtmajer. A Hybrid Epidemic Model for Deindividuation and Antinormative Behavior in Online Social Networks. Social Network Analysis and Mining (SNAM), January 2016.

  10. C. Griffin, S. Rajtmajer, and A. Squicciarini.  A Model of Paradoxical Privacy Behavior (Invited paper). International Conference on Collaboration and Internet Computing (IEEE CIC), October 2016.

  11. A. Tyagi, A. Squicciarini, S. Rajtmajer, C. Griffin. An In-Depth Study of Peer Influence on Collective Decision Making for Multi-party Access Control (Invited Paper). International Conference on Information Reuse and Integration (IEEE ICI), July 2016.

  12. S. Rajtmajer, C. Griffin and A. Squicciarini. Constrained Social-Energy Minimization for Multi- Party Sharing in Online Social Networks. International Conference on Autonomous and Multiagent Systems (AAMAS), Singapore, May 2016.

  13. S. Rajtmajer, C. Griffin and A. Squicciarini. Determining a Discrete Set of Site-Constrained Privacy Options for Users in Social Networks through Stackelberg Games. Conference on Decision and Game Theory for Security (GAMESEC), London, UK, November 2015.

  14. C. Liao, A. Squicciarini, C. Griffin and S. Rajtmajer. A Hybrid Epidemic Model for the Spread of Abusive Content in Online Social Sites. In Proc. 2015 IEEE/ACM International Conference on Advances in Social Networks Analysis and Mining (ASONAM), August 2015. 

  15. A. Squicciarini, S. Rajtmajer, Y. Liu and C. Griffin. Identification and Characterization of Cyberbullying Dynamics in an Online Social Network. In Proc. 2015 IEEE/ACM International Conference on Advances in Social Networks Analysis and Mining (ASONAM), August 2015. 

  16. S. Rajtmajer, C. Griffin, D. Mikesell and A. Squicciarini. An Evolutionary Game Model for the Spread of Non-Cooperative Behavior in Online Social Networks. In Proc. 30th ACM Symposium on Applied Computing, April 2015.

  17. S. Rajtmajer, A. Roy, R. Albert, P. Molenaar and F. Hillary. A Voxelwise Approach to Determine Consensus Regions-of-Interest for the Study of Brain Network Plasticity. Frontiers in Neuroanatomy, July 2015. 

  18. F. Hillary, N. Castellanos, R. Bajo and S. Rajtmajer. Hyperconnectivity as a Common Neural Response to Neurological Disorder. Neuropsychology, January 2015.

  19. U. Venkatesan, S. Rajtmajer and F. Hillary. Connectivity modeling and neuroplasticity after trauma. In Plasticity of Cognition in Neurologic Disorders. Oxford University Press, January 2015.

  20. F. Hillary, S. Rajtmajer, C. Roman, J. Medaglia, J. Slocomb, D. Good and G. Wylie. The Rich Get Richer: Brain Injury Elicits Hyperconnectivity in Core Subnetworks. PLoS One, August 2014. 

  21. C. Griffin, A. Squicciarini, S. Rajtmajer, M. Tentilucci and S. Lin. Site-Constrained Privacy Options for Users in Social Networks through Stackelberg Games. In Proc. Sixth ASE International Conference on Social Computing, May 2014.

  22. D. Bein, B. Madan, S. Phoha, S. Rajtmajer and A. Rish. Dynamic Data-Driven Sensor Network Adaptation

  23. for Border Control. In Proc. SPIE Defense, Security and Sensing, April 2013.

  24. S. Rajtmajer, B. Smith and S. Phoha. Non-Negative Sparse Autoencoder Neural Networks for the Detection of Overlapping, Hierarchical Communities in Networked Datasets. Chaos, December 2012. 

  25. S. Rajtmajer and D. Vukicevic. A Note on the Estrada Communicability Algorithm for Community Structure Detection in Complex Networks. Applied Mathematics and Computation, December 2010. 

  26. D. Vukicevic, S. Rajtmajer and N. Trinajstic. Trees with Maximal Second Zagreb Index and Prescribed Number of Vertices of Given Degree. MATCH Communications in Mathematical and Computer Chemistry, January 2008. 

  27. D. Vukicevic, J. Sedlar and S. Rajtmajer. A Graph-Theoretical Method for the Partial Ordering of Alkanes. Croatica Chemica Acta 80: 169-179, February 2007. 

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