I am a Research Scientist at Pacific Northwest National Laboratory (PNNL). I received my Ph.D. in Computer Science and Engineering from University of South Florida.

Current Interests Foundation Models (Language + Multimodal), Geometric Deep Learning (Dynamic Graphs), Privacy and Security

Contact

sameera1 [at] usf [dot] edu

Projects

Mega-AI: Foundation Models for Science and Security September 2021 to Present

We develop massive-scale, self-supervised, multimodal foundation models of scientific knowledge capable of general-purpose inferences to enable reasoning with existing knowledge and discovery of new knowledge across science and security domains.
Deep Learning Models (Graph Neural Networks) for Dynamic Heteregeneous Graphs September 2021 to Present
  • EXPERT: Global-Scale Cross-Lingual Proliferation Expertise Identification and Global Expertise Forecasting (National Nuclear Security Administration)
  • PANDA: AI-Driven Predictive Analytics to Enhance Nuclear Proliferation Detection in Urban Environments (National Nuclear Security Administration)
Modeling Information Diffusion Processes with Deep Learning Algorithms (DARPA SocialSim) January 2018 to September 2021

The objective of this work is to develop technologies for high-fidelity simulation of online social behavior (the spread and evolution of online information) while rigorously testing and measuring simulation accuracy
Structural Anonymization Techniques for Large, Labeled, and Dynamic Social Graphs January 2017 to December 2019

The objective of this work is to provide big data owners with tools to safely share their social networks data with the research community. The project aims to approach graph anonymization via two techniques for graph generation: dK-series techniques, introduced in the context of internet network generation, and Exponential Random Graph Model-based approaches (ERGM). My contribution is related to privacy/ utility measures, and how such graph annonymization techniques could apply on evolving graphs.

Recent Publications (Google Scholar)

[1]
Sameera Horawalavithana,Ellyn Ayton, Shivam Sharma, Scott Howland, Megha Subramanian, Scott Vasquez, Robin Cosbey, Maria Glenski, Svitlana Volkova Foundation Models of Scientific Knowledge for Chemistry: Opportunities, Challenges and Lessons Learned BigScience #5, Challenges & Perspectives in Creating Large Language Models, 60th Annual Meeting of the Association for Computational Linguistics (ACL), Dublin, Ireland, 2022
[2]
Sameera Horawalavithana,Ellyn Ayton, Anastasiya Usenko, Robin Cosbey, Shivam Sharma, Jasmine Eshun, Maria Glenski, Svitlana Volkova EXPERT: Public Benchmarks for Dynamic Heterogeneous Academic Graphs Graph Learning Benchmark, The Web Conference, 2022
[3]
Sameera Horawalavithana, Nazim Choudhury, John Skvoretz, and Adriana Iamnitchi. Online Discussion Threads as Conversation Pools: Predicting the Growth of Discussion Threads on Reddit Computational and Mathematical Organization Theory (CMOT), 2021
[4]
Sameera Horawalavithana, Kin NG and Adriana Iamnitchi. Drivers of Polarized Discussions on Twitter during Venezuela Political Crisis, 13th ACM Web Science Conference (WebSci), Southampton, UK, 2021
[5]
Sameera Horawalavithana,Ravindu De Silva, Mohamed Nabeel, Charitha Elvitigala, Primal Wijesekara, and Adriana Iamnitchi. Malicious and Low Credibility URLs on Twitter during the AstraZeneca COVID-19 Vaccine Development, International Conference on Social Computing, Behavioral-Cultural Modeling, & Prediction and Behavior Representation in Modeling and Simulation (SBP-BRiMS), Washington DC, USA, 2021 Best Paper (COVID Track)
[6]
Sameera Horawalavithana, Kin NG and Adriana Iamnitchi. Twitter is the Megaphone of Cross-Platform Messaging on the White Helmets, International Conference on Social Computing, Behavioral-Cultural Modeling, & Prediction and Behavior Representation in Modeling and Simulation (SBP-BRiMS), Washington DC, USA, 2020
[7]
Sameera Horawalavithana, Juan Arroyo Flores, John Skvoretz, and Adriana Iamnitchi. Behind the Mask: Understanding the Structural Forces That Make Social Graphs Vulnerable to Deanonymization, IEEE Transactions on Computational Social Systems (2019)
[8]
Sameera Horawalavithana, Abhishek Bhattacharjee, Renhao Liu, Nazim Choudhury, Lawrence O. Hall and Adriana Iamnitchi. Mentions of Security Vulnerabilities on Reddit, Twitter and GitHub, IEEE/WIC/ACM International Conference on Web Intelligence, Thessaloniki, Greece, October, 2019

Technical Reports

[1]
Sameera Horawalavithana Data-driven Studies on Social Networks: Privacy and Simulation Ph.D. Dissertation, Department of Computer Science and Engineering, University of South Florida, June 2021 (Nomination for Outstanding Thesis and Dissertation)
[2]
Cloud based publish/subscribe model for Top-k matching over continuous data-streams (Best Undergraduate Thesis)
[3]
"What Draws Your Attention?": Analyzing the Impact of Duplicate Hoaxes coursework project, Social Media Mining, December, 2018
[4]
Distributed Software Transactional Memory Literature review, January 2014.
[5]
On the Design of an Efficient Hardware Accelerator for Large Scale Graph Analytics Literature review, December 2016.
[6]
Temporal Patterns of Motifs courework project, Social Network Analysis, May 2017.
[7]
Estimating Measurement Probability Distributions with Mixture Density Networks courework project, Deep Learning, May 2018.
[8]
Object state recognition for learning manipulation tasks in robotics courework project, Deep Learning, May 2018.
[9]
Some cool security exploits developments, System Security, Dec 2017 smash-stack, heap-spray, heap-spray-repo and vold-daemon
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