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Anastasios Nikolas Angelopoulos
Arena.ai
2,728 posts
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Anastasios Nikolas Angelopoulos
Arena.ai
@ml_angelopoulos
Measuring intelligence @arena. Statistics, model evaluation. Formerly @Berkeley_EECS, @StanfordEng, student researcher @GoogleDeepMind.
angelopoulos.ai
Joined September 2019
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  • Pinned
    user avatar
    Anastasios Nikolas Angelopoulos
    Arena.ai
    @ml_angelopoulos
    Jun 29
    Arena has crossed $100M in annualized revenue run rate, eight months after launching our evaluation product. With our recent release of Agent Mode, millions of users on Arena are doing real work with agents, from coding to document analysis, in long-running, multi-turn sessions
    137K
  • user avatar
    Anastasios Nikolas Angelopoulos
    Arena.ai
    @ml_angelopoulos
    Sep 7, 2022
    📢Huge update to Gentle Introduction to Conformal Prediction📢 arxiv.org/abs/2107.07511 Notebooks for EVERY example, easy-2-run WITHOUT model/data download. Open+run in Colab!✅ New repo here: github.com/aangelopoulos/… New sections on time-series and risk control!✅ More in 🧵
    Updated table of contents to Gentle Introduction, including conformal risk control, conformal under distribution drift, 5 worked examples of conformal prediction, and full conformal prediction.
  • user avatar
    Anastasios Nikolas Angelopoulos
    Arena.ai
    @ml_angelopoulos
    Nov 19, 2024
    🚨 New Textbook on Conformal Prediction 🚨 arxiv.org/abs/2411.11824 “The goal of this book is to teach the reader about the fundamental technical arguments that arise when researching conformal prediction and related questions in distribution-free inference. Many of these
    61K
  • user avatar
    Anastasios Nikolas Angelopoulos
    Arena.ai
    @ml_angelopoulos
    Jan 25, 2023
    📯Prediction-Powered Inference📯 arxiv.org/abs/2301.09633 With the rise of AlphaFold etc., people are using ML predictions to replace costly experimental data. But predictions aren't perfect; can we still use them for rigorous downstream inferences? The answer: yes. A 🧵
    Left: A picture of a phosphorylated protein. Middle-Right: confidence intervals. The prediction-powered confidence interval is correct, while the imputed one is too small and the classical one is too big.
    203K
  • user avatar
    Anastasios Nikolas Angelopoulos
    Arena.ai
    @ml_angelopoulos
    Nov 9, 2023
    Prediction-powered inference was published today as a research article in Science! @ScienceMagazine science.org/doi/full/10.11… Check it out - and if ur interested in collaborating, learning about PPI, or ML for science more broadly, plz reach out! Also see Berkeley News
    user avatar
    Anastasios Nikolas Angelopoulos
    Arena.ai
    @ml_angelopoulos
    Jan 25, 2023
    📯Prediction-Powered Inference📯 arxiv.org/abs/2301.09633 With the rise of AlphaFold etc., people are using ML predictions to replace costly experimental data. But predictions aren't perfect; can we still use them for rigorous downstream inferences? The answer: yes. A 🧵
    Left: A picture of a phosphorylated protein. Middle-Right: confidence intervals. The prediction-powered confidence interval is correct, while the imputed one is too small and the classical one is too big.
    102K
  • user avatar
    Anastasios Nikolas Angelopoulos
    Arena.ai
    @ml_angelopoulos
    Sep 20, 2025
    xAI’s Grok 4 fast is the #1 small model in LMArena. Grok’s ascent to the top of the Arena:  – Grok 2 (August 2024): debuted at #3 on the overall leaderboard  – Grok 3 (March 2025): debuted at #1 on the overall leaderboard  – Grok 4 fast (Sept 2025) → #1 in search and the #1
    user avatar
    Arena.ai
    @arena
    Sep 19, 2025
    🚨 Leaderboard Disrupted! Grok-4-fast by @xai has arrived in the Arena, and it’s shaking things up! ⚡️ 🏆 #1 on the Search Leaderboard Tested under the codename “menlo,” Grok-4-fast-search just rocketed to the top spot with the community. 💠 Tied for #8 on the Text Leaderboard
    28K
  • user avatar
    Anastasios Nikolas Angelopoulos
    Arena.ai
    @ml_angelopoulos
    Aug 1, 2023
    🤖Conformal PID Control for Time-Series Prediction🕹 📝w/Candès & Tibshirani! arxiv.org/abs/2307.16895 Is conformal prediction out of control🤪? Yes! CP can be thought of as PID control, giving stronger guarantees+algorithms that predict distribution shifts as they happen! A🧵
    41K
  • user avatar
    Anastasios Nikolas Angelopoulos
    Arena.ai
    @ml_angelopoulos
    Nov 9, 2025
    Have you ever considered that the model made by @MistralAI (a French company) might somehow be better for French users? This is why it's important to have independent scientific benchmarks from real-world usage... sometimes reality can surprise you and defy intuition.
    user avatar
    Lisan al Gaib
    @scaling01
    Nov 8, 2025
    The french government created an LLM leaderboard akin to lmarena, but rigged it so that Mistral Medium 3.1 would be at the top Mistral 3.1 Medium > Claude 4.5 Sonnet or Gemma3-4B and a bunch of Mistral models > GPT-5 ??????????????????? LMAO
    58K
  • user avatar
    Anastasios Nikolas Angelopoulos
    Arena.ai
    @ml_angelopoulos
    Oct 26, 2025
    It's Zareen's, man! And yes, we love it
    user avatar
    SemiAnalysis
    @SemiAnalysis_
    Oct 26, 2025
    Zareen is one of the go to places for many SF Bay Area AI researchers to get a quick bite. Most of the food is very good and was even on the Michelin guide in 2020. AI researchers not experienced with the Indian cuisine will commonly order their chicken tikka masala with garlic
    69K
  • user avatar
    Anastasios Nikolas Angelopoulos
    Arena.ai
    @ml_angelopoulos
    Mar 1, 2022
    This is a huge moment for conformal prediction. @sirbayes has included a section of his ML book on conformal prediction, based on our Gentle Introduction (w/@stats_stephen + including some of our figures). This is becoming mainstream. The whole community should be proud.
    user avatar
    Kevin Patrick Murphy
    @sirbayes
    Feb 28, 2022
    I am delighted to announce that a draft of my latest book, “Probabilistic Machine Learning: Advanced Topics”, is now available online at probml.ai. It covers #DeepGenerativeModels, #BayesianInference, #Causality, #ReinforcementLearning, #DistributionShift, etc.
  • user avatar
    Anastasios Nikolas Angelopoulos
    Arena.ai
    @ml_angelopoulos
    Jul 13, 2023
    🥹🥹🥹 thank u ☺️
    16K
  • user avatar
    Anastasios Nikolas Angelopoulos
    Arena.ai
    @ml_angelopoulos
    Aug 26, 2025
    Here's a summary of today's big news: unpeeling the story of a tiny banana. 🤏 🍌 Gemini-2.5-Flash-Image-Preview by @GoogleDeepMind is an image editing model that has taken the world by storm. It allows conditioning on both text and images, so it can follow textual instructions
    17K
  • user avatar
    Anastasios Nikolas Angelopoulos
    Arena.ai
    @ml_angelopoulos
    Aug 7, 2025
    Millions of people have used GPT-5 under the codename summit on LMArena over the past couple weeks 🏔️ The people have spoken: GPT-5 is #1 on EVERYTHING in LMArena. 🧮 Math 💻 Coding 🖋️ Creative writing Check out an example of its multifaceted intelligence in the 🧵
    user avatar
    Arena.ai
    @arena
    Aug 7, 2025
    GPT-5 is here - and it’s #1 across the board. 🥇#1 in Text, WebDev, and Vision Arena 🥇#1 in Hard Prompts, Coding, Math, Creativity, Long Queries, and more Tested under the codename “summit”, GPT-5 now holds the highest Arena score to date. Huge congrats to @OpenAI on this
    73K
  • user avatar
    Anastasios Nikolas Angelopoulos
    Arena.ai
    @ml_angelopoulos
    Mar 31, 2021
    We built an eye tracker using an event-based camera that operates at 10KHz and above in a low-power and small form-factor. It has accuracy of 0.5deg in central FOV. See the oral tomorrow at #IEEEVR21, journal paper in TVCG, and website: computationalimaging.org/publications/e… #vr #ar #ai 🧵1/n
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