<?xml version="1.0" encoding="UTF-8"?><rss version="2.0"><channel><title>Ben Chen</title><description>Technical notes on retrieval, ranking, and learning systems.</description><link>https://benchen.dev/</link><item><title>HOBIT Retrieval Training</title><link>https://benchen.dev/blog/hobit-retrieval-training/</link><guid isPermaLink="true">https://benchen.dev/blog/hobit-retrieval-training/</guid><description>A compact note on training retrievers against the failures their own index exposes.</description><pubDate>Fri, 17 Jul 2026 00:00:00 GMT</pubDate><category>retrieval</category><category>ranking</category><category>training</category></item><item><title>PageRank at Web Scale</title><link>https://benchen.dev/blog/pagerank-at-web-scale/</link><guid isPermaLink="true">https://benchen.dev/blog/pagerank-at-web-scale/</guid><description>A short refresher on random surfers, sparse matrices, and the operational shape of PageRank.</description><pubDate>Thu, 16 Jul 2026 00:00:00 GMT</pubDate><category>pagerank</category><category>graphs</category><category>ranking</category></item><item><title>PPO Entropy Collapse</title><link>https://benchen.dev/blog/ppo-entropy-collapse/</link><guid isPermaLink="true">https://benchen.dev/blog/ppo-entropy-collapse/</guid><description>Why clipped policy updates can still lose exploration pressure, and what to watch during training.</description><pubDate>Wed, 15 Jul 2026 00:00:00 GMT</pubDate><category>ppo</category><category>reinforcement-learning</category><category>optimization</category></item></channel></rss>