James Verbus
AI systems for
adversarial settings.
At LinkedIn, I worked on automation detection and AI-generated profile photos, and built the Spark/Scala isolation-forest library.
What I work on
Representative work
Sequence modeling
Deep learning for abusive activity sequences
Detecting low-volume scrapers from the order and timing of their requests.
Research
Finding AI-generated faces in the wild
Testing a face detector on GAN and diffusion models, including generators withheld from training.
Workshop
Reinforcement learning for orbital transfers
Training PPO policies for orbital transfers and comparing them with the Hohmann solution.
Open source anomaly detection
Open-source Spark/Scala isolation-forest library
How random partitions identify unusual account activity, and how to distribute training and scoring in Spark.
Career
Background
At LinkedIn, most recently as a Senior Staff Machine Learning Engineer, I built production detection systems for Trust. I created and open-sourced the Spark/Scala isolation-forest library and led AI productivity work for Trust engineering teams.
Before LinkedIn, I earned my Ph.D. in physics at Brown working on LUX, one of the world's most sensitive dark-matter detectors. The common thread is practical measurement: extracting weak signals from noisy data, checking uncertainty, and making systems useful when ground truth is incomplete.
Projects
Open Source
Isolation Forest
Distributed Isolation Forest and Extended Isolation Forest for Spark, with ONNX export for standard Isolation Forest models.
Research / Publications
2024
Finding AI-Generated Faces in the Wild
G.J. Aniano Porcile, J. Gindi, S. Mundra, J.R. Verbus, H. Farid
CVPR Workshop on Media Forensics
Paper ·
arXiv:2311.08577
2023
Exposing GAN-Generated Profile Photos from Compact Embeddings
S. Mundra, G.J. Aniano Porcile, S. Marvaniya, J.R. Verbus, H. Farid
CVPR Workshop on Media Forensics
Paper
2024
Deep Learning to Detect Abusive Sequences of User Activity in Online Network
J.R. Verbus, B. Wang
US Patent 11,936,682
Patent
Talks / Videos
2025
Brown AI Winter School 2025: Exploring LLMs and RAG
A 2.5 hour interactive workshop at the 2025 AI Winter School, hosted by the Center for the Fundamental Physics of the Universe at Brown University.
AI Winter School 2025, Center for the Fundamental Physics of the Universe at Brown University.
2024
SXSW 2024 Panel with DARPA: Real or Not - Defending Authenticity in a Digital World
A panel with DARPA on detecting synthetic media and assessing the authenticity of online content.
SXSW and DARPA.
DARPA recap
2019
Fighting Abuse @Scale: Preventing Abuse Using Unsupervised Learning
Using Isolation Forest to find unusual account behavior without labeled training examples.
@Scale Conference.
github.com/linkedin/isolation-forest ·
Original @Scale page
Contact
Questions or corrections? Email me.