Versioned Late Materialization for Ultra-Long Sequence Training in Recommendation Systems at Scale

This batch contains research on large-scale recommender/IR engineering and evaluation, with several items raising privacy and ML-security considerations. Notable items: a production-grade health-system semantic search that indexes 166M clinical notes (HIPAA governance claimed) using embeddings and a vector DB; GeoSearch which integrates web-scale reverse image search and web scraping; a "versioned late materialization" system that explicitly addresses Online-to-Offline (O2O) consistency and leakage prevention for ultra-long user interaction histories; and multiple generative/RAG and grounding/