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PRISM and the Art of Not Losing Meaning

Catalogs are messy. A shopper clicks a lipstick because it is on discount, ignores a better product because the thumbnail is dull, buys a cable for someone else, and later returns to search for something completely unrelated. A recommender system sees all of this as signal. Some of it is useful. Some of it is noise wearing a very confident jacket. ...

January 26, 2026 · 16 min · Zelina
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Don’t Just Fuse It — Align It: When Multimodal Recommendation Grows a Spine

A product page has a photo. A description. A category. A few user clicks. Maybe a rating, if the platform is lucky. The ordinary recommender-system reflex is to pour all of that into the model and call it “multimodal.” Image embedding here, text embedding there, concatenate, pool, sum, ship. Then, when performance disappoints, add another feature extractor, another graph layer, another auxiliary objective, and hope the leaderboard blushes. ...

January 20, 2026 · 19 min · Zelina
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No Prompt Left Behind: How Shopee’s CompassMax Reinvents RL for Giant MoE Models

Rollouts are expensive little creatures. They consume GPU time, produce long reasoning traces, wait for reward computation, and then—if the reward signal is flat—contribute exactly nothing to learning. The GPU was busy. The training dashboard looked serious. The model learned no usable distinction. Very productive, in the same way a meeting with twelve people and no decision is productive. ...

December 9, 2025 · 18 min · Zelina
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The Joy of Many Minds: How JoyAgents-R1 Unleashes the Power of Multi-LLM Reinforcement Learning

TL;DR for operators A naming note before the machinery starts: the existing Cognaptus title says JoyAgents-R1, but the arXiv paper itself names the benchmark HiMA-Ecom and the training method HiMA-R1. This revision uses the paper’s terminology, because accuracy is not decorative trim. The paper is useful for operators because it does not simply say “use more agents.” That slogan is old, cheap, and usually followed by a demo in which three chatbots politely agree with one another until the invoice arrives. The real contribution is more specific: the authors build a hierarchical e-commerce assistant benchmark, then train the master agent and specialised sub-agents jointly with reinforcement learning instead of optimising them as isolated prompt puppets.1 ...

June 25, 2025 · 17 min · Zelina