Three months building a neural search and recommendation system over roughly 600,000
documents in OpenSearch. Covers why ANN covers only ~10% of your index, why filters
must go inside the ANN clause, the silent recall collapse from omitting
pagination_depth, the HNSW parameter ceiling chain, the copy_to lexical recall
pattern, and how to tell an ML-layer 429 from a proxy 502.
Building a knowledge graph over Nigeria's NHMIS data for all 44 Kano LGAs, with an
AI agent on top. Covers the dual-grain graph model, idempotent DHIS2 ingestion,
why six Cypher templates beat one text2cypher tool, and the traversal that tells a
real decline in service delivery apart from a facility that stopped filing returns.
A full technical walkthrough of the NODES 2026 talk: bipartite knowledge graph
design, FastRP embeddings, graph-aware hard negative sampling via constrained
random walks, stratified resampling to correct power-law skew, Random Forest on
element-wise embedding products (OOB AUPRC 97.3%), and Platt re-calibration from
50% sampled prior to 5.5% population prior.