Posts
All the articles I've posted.
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Java Study #1 — First Java Run · Syntax Overview · OOP Basics (Classes · Encapsulation · Inheritance · Interfaces)
Starting Java study to fill in my lacking backend and production experience. In one day, I went from installing Java to covering the switch statement's -> arrow syntax, for-each, the need for double casting in integer division, the public class file rule, encapsulation with private + getter, the difference with and without static, the @Override annotation, and connecting interfaces with implements. Having Python / C++ experience, many concepts were already familiar.
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RAG Embedding Comparison — Measuring recall@k on My Blog Data (OpenAI vs bge-m3)
After establishing the ["feeling-based benchmarking → numeric benchmarking" principle](/en/posts/quant-study-00-pandas) in my quant retrospective, I actually quantified an embedding model comparison this time. I indexed 441 chunks from my blog posts with OpenAI text-embedding-3-small and bge-m3 respectively, then measured recall@3 with a test set of 20 question-answer source pairs. Overall: OpenAI 80% vs bge-m3 90%. bge-m3 hit 100% on hard-difficulty questions — the decisive factor was connecting to the source text by meaning even when words didn't overlap. On easy questions, the misses turned out to be caused by typos (cladue, underscores) — a twist showing the grading criteria itself was wrong.
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Eval Study #2 — The Pitfalls of Similarity-Based Evaluation, 5 Principles of Test Set Design, and a Misunderstanding About the Term 'Regression Test'
My second session studying Eval. I ran similarity-based evaluation (embedding cosine similarity) myself and got an unexpected result — both OpenAI's text-embedding-3-small and bge-m3 gave the highest score to the 'wrong answer.' This is because similarity captures topical/expressive closeness, not content correctness. Just a difference in markdown formatting can swing similarity scores significantly. In practice, combining similarity with LLM-as-Judge is the standard approach. Also covers 5 principles of test set design, plus a terminology correction: it's not a 'regression test,' it's improvement validation (A/B).
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Eval Study #1 — Ending 'Vibe Benchmarking' · Accuracy-based + First LLM-as-Judge Implementation
Eval Study #1 — Ending 'Vibe Benchmarking' · Accuracy-based + First LLM-as-Judge Implementation