Insights23 min read
The Missing Layer: A Structural Gap in the AI Infrastructure Stack
by Jaepil Jeong | April 10, 2026
Between models and hardware lies an invisible structural gap β a data layer that should exist but doesn't. We examine why the current AI infrastructure stack is fragmented, why this is a structural problem rather than a transitional one, and what conditions a proper solution must satisfy. We then present UQA and the Cognica engine as one concrete response to these conditions.
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Research7 min read
Vector Scores Are Not Probabilities: Likelihood Ratio Calibration for Hybrid Search
by Jaepil Jeong | March 25, 2026
A cosine similarity of 0.85 tells you an angle, not a probability. We show how to transform vector similarity scores into calibrated relevance probabilities using distributional statistics that ANN indexes already compute β completing the probabilistic unification of text and vector retrieval.
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Tech15 min read
Building a Probabilistic Search Engine: Bayesian BM25 and Hybrid Search
by Jaepil Jeong | February 1, 2026
Modern search systems struggle to combine lexical matching with semantic understanding. We explore how we built a probabilistic ranking framework in Cognica Database that transforms BM25 scores into calibrated probabilities, enabling principled fusion of text and vector search results.
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Insights4 min read
An AI Database That Works Identically On-Device
by Tim Yang | December 23, 2025
We examine the database architecture changes required by on-device AI. Just as SQLite was the answer for on-device computing, on-device AI requires a new database that integrates transactions, analytics, full-text search, and vector search. We explain why Cognica works identically on-device and on servers.
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Insights5 min read
Structural Limitations of Legal Case Search and the Need for Single DB with Vector Search
by Tim Yang | December 9, 2025
This article provides a technical analysis of why legal case search is challenging in the legal services market. We examine the structural characteristics of legal case data and the limitations of existing distributed architectures (RDB + ElasticSearch + Vector DB), and explain why integrated search based on a single database is necessary.
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Insights3 min read
Distributed Databases: A Structural Constraint in the AI Era
by Tim Yang | November 17, 2025
Exploring how function-based distributed database architectures become structural constraints in the AI era. We examine the limitations and complexity of traditional approaches combining OLTP, OLAP, FTS, and Vector DB, and introduce Cognica's unified database as a technical turning point.
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Insights6 min read
Why a Single Database?
by Tim Yang | November 11, 2025
Moving beyond the complexity and limitations of the era of specialized databases, we explore why a unified database is now essential. Discover the value of Cognica's integrated database that provides OLTP, OLAP, cache, FTS, and vector search in a single engine, and the future direction of databases in the AI era.
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Engineering8 min read
Why NOT Operations are Difficult in Vector Search
by Jaepil Jeong | February 3, 2025
We discuss why NOT operations are difficult in vector search.
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Engineering14 min read
Why Did We Store Two-Dimensional Vectors for Vector Search?
by Cognica Team | July 17, 2024
Explains the limitations and characteristics of vector embeddings and covers the improvements made to store them.
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Engineering13 min read
Searching Case Law Data with Natural Language
by Cognica Team | July 4, 2024
Explains how to build a natural language search service by applying vector search to a case law search demo using FTS.
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