James Han

Systems and infrastructure across the stack, from the manufacturing line to tooling for neural recordings from implants, and hardware-in-the-loop testing across firmware, BCI, and robot teams.

Search and retrieval behind Sidekick, AI Search, Queue Bot, and the Help Center: hybrid lexical and semantic fusion, learned ranking and reranking, term weighting, document features from click evidence, memory over past conversations, ML eval pipelines and LLM-as-a-judge experimentation.

Privacy engineering and machine learning in Firefox: tracker cost estimation under a per-request latency budget, learned representations of URLs, on-device inference so browsing data never leaves the machine, the new tab privacy widget and its multi-process telemetry, privacy shims for broken sites, and content sanitization.

Used by 30k+ students

Inverted index to ranked result, from a document on disk

Per-request cost estimation for blocked trackers, on-device ONNX

Training notes and race logs, Team Canada, 2027 Age-Group Worlds