Information Security

🎭 Improv Utrecht Presents a Show Like No Other! 🎭 The advanced graduates of the course "On Stage!" of trainer Rutger Holmes will take the stage at Theaterhuis De Berenkuil to showcase their skills in a very fun and interactive show. Expect improv games, improvised singing and beautiful meaningful scenes. 💡 What is Improv? Improv is live, unscripted theatre where anything can happen! The performers create characters, scenes, and entire stories from scratch, all based on audience suggestions and their quick-thinking creativity. It’s spontaneous, electric, and completely unique—no two shows are ever the same! 🎟 Tickets Now Available! Don't miss this one-night-only spectacle of storytelling and laughter. Secure your tickets online before they’re gone! Book your ticket at [improv-utrecht.weticket.io](http://improv-utrecht.weticket.com/) : €14 plus €0,7 service fee Before and after the show we have a very nice bar to meet & greet people. 📅 When? Friday 24 April 20:00h. Bar open 19:15 📍 Where? Theaterhuis De Berenkuil, Biltstraat 166 Join us for a night of creativity, comedy, and community—we can’t wait to see you there! Find out more about Improv Utrecht, our other shows and courses at [www.improvutrecht.nl](http://www.improvutrecht.nl/)

This session focuses on **Sparse and Ranking in Modern Retrieval**, featuring two speakers: **Simon Lupart** from University of Amsterdam and **Chuan Meng** from University of Edinburgh. **Location:** Science Park 904, Room C3.161 **Date**: Friday, April 24 **Time**: 16:00-17:00 **Zoom** **link**: [https://uva-live.zoom.us/j/65011610507](https://uva-live.zoom.us/j/65011610507) Details below: **Speaker #1**: **Simon Lupart** from University of Amsterdam **Title:** On the Challenges and Opportunities of Learned Sparse Retrieval for Code **Abstract:** Retrieval over large codebases is a key component of modern LLM-based software engineering systems. Existing approaches predominantly rely on dense embedding models, while learned sparse retrieval (LSR) remains largely unexplored for code. However, applying sparse retrieval to code is challenging due to subword fragmentation, semantic gaps between natural-language queries and code, diversity of programming languages and sub-tasks, and the length of code documents, which can harm sparsity and latency. We introduce SPLADE-Code, the first large-scale family of learned sparse retrieval models specialized for code retrieval (600M-8B parameters). Despite a lightweight one-stage training pipeline, SPLADE-Code achieves state-of-the-art performance among retrievers under 1B parameters (75.4 on MTEB Code) and competitive results at larger scales (79.0 with 8B). We show that learned expansion tokens are critical to bridge lexical and semantic matching, and provide a latency analysis showing that LSR enables sub-millisecond retrieval on a 1M-passage collection with little effectiveness loss. **Bio**: Simon is a third year PhD student at the University of Amsterdam, working on Information Retrieval and LLMs. He has graduated from a computer science engineering school in France, made an Erasmus exchange in London, during his master, at the imperial college london, and worked in the industry for 2 years at naver labs europe. Now he will present his latest work from an internship at naver labs europe. **Speaker #2:** Chuan Meng from University of Edinburgh **Title**: Revisiting Text Ranking in Deep Research **Abstract**: Deep research has emerged as an important task that aims to address hard queries through extensive open-web exploration. To tackle it, most prior work equips large language model (LLM)-based agents with opaque web search APIs, enabling agents to iteratively issue search queries, retrieve external evidence, and reason over it. Despite search's essential role in deep research, black-box web search APIs hinder systematic analysis of search components, leaving the behaviour of established text ranking methods in deep research largely unexplored. In this talk, we revisit key findings and best practices for text ranking methods in the deep research setting. In particular, we examine their effectiveness from three perspectives: (i) retrieval units (documents vs. passages), (ii) pipeline configurations (different retrievers, re-rankers, and re-ranking depths), and (iii) query characteristics (the mismatch between agent-issued queries and the training queries of text rankers). We perform experiments on BrowseComp-Plus, a recent deep research dataset with a fixed document corpus, evaluating a broad spectrum of text ranking methods across diverse setups. We find that agent-issued queries typically follow web-search-style syntax (e.g., quoted exact matches), favouring lexical, learned sparse, and multi-vector retrievers. Passage-level units are more efficient under limited context windows, and avoid the difficulties of document length normalisation in lexical retrieval. Re-ranking consistently improves performance, with deeper re-ranking depths amplifying gains. Translating agent-issued queries into natural-language questions significantly bridges the query mismatch and improves effectiveness. Related paper: [https://arxiv.org/pdf/2602.21456](https://arxiv.org/pdf/2602.21456) **Bio**: Chuan Meng is a postdoc at the University of Edinburgh, working with Dr. Jeff Dalton. He received his PhD from the University of Amsterdam in June 2025, supervised by Prof. Maarten de Rijke and Dr. Mohammad Aliannejadi. He was formerly an Applied Scientist Intern at Amazon. His research focuses on agentic information retrieval (IR) and deep research. He has published 25+ papers in top-tier venues such as SIGIR, ACL, EMNLP, NAACL, CIKM, AAAI, ECIR, and TOIS, with 650+ citations on Google Scholar and an h-index of 16. He has co-organised tutorials and workshops at SIGIR 2025, WSDM 2025, ECIR 2024–2026, SIGIR-AP 2024. **Counter:** SEA Talks #303 and #304.

With warm & good weather on the horizon again, it's time again to get more picnic-y & outdoors-y 🌄 For this new season, let's revisit the old picnic gathering formula, but add into the night vibe & spicy dance theme (in this case tango, because other dances are oversaturated with events 😊) The premise: A picnic gathering starting from 19:00 & ending 23:00 sharp Since it's evening vibes, BYO food/drinks/games still applies but think time appropriate (don't go big on alcohol though!) Dancing aspect, music starts 20:00 & ends 23:00 sharp! Exact location in Griftpark: To be concluded, but assume close to where the meetup event location currently is set at Additional notes for the tango aspect: * you're very much welcome to join in & dance, even with no experience. I can show you a thing or two so you can get a taste & give it a go 😊 Depending on how many, either via a quick group tryout or I help you out individually * The tango aspect of the event is through the Utrecht Tango Cafe Milonga community (also organized by Constantinos) More info --> https://www.utrechtcafemilonga.com If you have any further questions, feel free to message the host Depending on the time & weather, and whether people are up for it, follow-up drinks can always follow later that day. To those interested, I hope to see you there! 😄

**Join us for Spring Drinks for Expats & Locals!** Celebrate the arrival of spring with fresh connections and great company! 🌿 We’re excited to invite you to Spring Drinks for Expats & Locals. This evening is all about enjoying the season of renewal with meaningful conversations, laughter, and a welcoming international crowd. **What to expect** * A lively and inclusive atmosphere to enjoy good company. * Conversations with a diverse mix of locals and internationals. * A laid-back evening of cultural exchange, friendships, and fun. **Who should join** * **Expats** looking to expand their social circle and make new friends. * **Locals** eager to share their culture and connect with an international crowd. * **Anyone** looking for a relaxed, social evening filled with great energy and good vibes. Don't miss out - **RSVP now** and join us for an unforgettable evening! Join the WhatsApp group: brand.page/expatslocalswhatsapp Follow us on Instagram: instagram.com/expats.locals Become a Welcomer: https://www.expatslocals.com/become-a-welcomer

Welcome to the first Cocktail & Mocktail Crawl: Pre King's Day Weekend Edition! **🍊🍹** After a successful first Cafe Crawl and with a second one just around the corner, it's time to introduce something new. This is the Cocktail & Mocktail Crawl. We're kicking off the King's Day weekend the right way, with good drinks, great company, and a little orange. Wear or bring something orange to get into the King's Day spirit! We meet at the Neude and from there we visit two great bars with a delicious cocktail & mocktail menu. At both stops you'll be put in small groups of 4 to 6 people, so there's nice space to connect and have good conversations. ⚠️ Not sure if you can make it? Please free up your spot for someone else.

**This might be the girls night you didn’t know you needed.** Many women are living in constant “on” mode- always busy, always giving. And somewhere along the way, we forget how good it feels to simply *be together*. This is your invitation to a real **girls night out**. Every 3 weeks we come together to relax, laugh, connect and support each other — without pressure, without fixing, without performance. **When women gather in a safe and supportive space, something powerful happens.** We uplift each other through shared laughter, honest conversations, and non-judgement presence. Being around other women who get it can make everything feel a little lighter and brighter. It helps us feel less alone, more supported, emotionally stronger - sometimes simply by being in the same room together. Sometimes we talk. Sometimes we listen, Sometimes we laugh - and even sing - until our bellies hurt. You’re free to share what’s on your mind, or simply enjoy the energy of being around other women who get it. There’s no agenda. No judgement. Just genuine connection, joy, and friendships that feel *easy and real.* And often, there’s that quiet thought: *“oh wow, I didn’t know I needed this.”* All I ask is that you come exactly as you are — tired, joyful, quiet, loud, curious, or unsure. Everything is welcome. We meet every 3 weeks - The upcoming months it will only be in Utrecht. later on we will switch between Utrecht, Amsterdam and Leiden - because connection grows when we keep showing up for each other — not perfectly, just honestly. ✨ Come as you are. ✨ Leave feeling lighter, more connected, and a little more yourself.

*Since the guided meditations for this event are in Dutch, this description is too.* Wil je je drukke week afsluiten en ontspannen aan het weekend beginnen? Dan ben je geheel vrijblijvend welkom bij de vrijdagavond meditatie van [Jewel Heart](https://www.jewelheart.nl/). Deze meditatieavond heeft een licht en open karakter. De meditaties bestaan uit drie delen. We beginnen met het gewaarworden van je lichamelijke sensaties. In een korter deel twee doen we een loopmeditatie en in deel drie is er een eenvoudige, geleide visualisatie meditatie. Het geheel wordt afgesloten met een gesprek onder het genot van een kop thee, voor wie daar zin in heeft. 📍[Jewel Heart, Hatertseveldweg 284, Nijmegen](https://maps.app.goo.gl/D4FzqLbkaqs2JNDG8). Loop de oprit op en dan is de ingang aan je rechterzijde 🕒Zaal open vanaf 19.30 uur, meditatie van 20.00 tot 21.00 Je bent van harte welkom! Aan deze activiteit kun je per keer meedoen. Er zijn geen verplichtingen. Op vrijwillige basis kun je op de avond zelf een donatie doen. Kijk ook naar onze -[Open activiteiten](https://www.jewelheart.nl/nl/open-activiteiten/) -[Cursussen](https://www.jewelheart.nl/nl/cursussen-overzicht/)

Maandelijkse, informele meetup voor mensen die actief zijn in **Bitcoin, crypto, investeren of de techwereld**. Geen presentaties of verkoop — gewoon goede gesprekken en echte connecties. \#\#\# Wat kun je verwachten? * Gesprekken over Bitcoin, crypto, investeren en tech * Delen van inzichten, ervaringen en strategieën * Praten over groei, fouten en lessen * Leren van elkaar, zonder druk of verwachtingen * Eventueel individueel handelen (op eigen verantwoordelijkheid) \#\#\# Voor wie? Deze meetup is bedoeld voor mensen die: * Interesse hebben in crypto, investeren of tech * Respectvol met anderen omgaan * Waarde hechten aan een veilige en vertrouwde omgeving \#\#\# Waarden Respect staat centraal. God en geloof worden gerespecteerd. Vloeken en onrespectvol gedrag worden niet geaccepteerd. Geen hypes — **gewoon echte gesprekken**.

Hi everyone! For those who want to enjoy nature, trips/excursions, and generally a more outdoors setting, let’s get together for a hiking excursion! The plan is to meet at Utrecht Central (and/or a train station that is closest to our hiking area), and then we begin our hiking route. For first-timers (or as a helpful reminder 😉), I recommend that you wear a comfy outfit & shoes and bring water & a snack or two. At some point during the excursion, we can do a break in-between to rest and eat/drink for a while. Depending on the time & weather, and whether people are up for it, there’s always the possibility of follow-up drinks later that day. More info about the route/location: https://www.komoot.com/smarttour/4265776?ref=atd The route is a 25km one, starting & finishing at Den Bosch Train station. To my knowledge, dogs are allowed, but double check beforehand More tips on finding the group along with helpful contact info with the host will follow in the comments the day before the meetup. To those interested, hope to see you there! 😄 In case of bad (NL) weather, the event might be moved to another day.

* We **start at 11:30** at Train Station Driebergen-Zeist (in front of: NS Stationshuiskamer https://maps.app.goo.gl/rxbgbhe877qTaoE2A * Length: \~16 km (4 - 5 hr hiking) * What to bring: lunch, water, snack. * For whom: As always, sporty folks that like to combine social event with being active in nature. **Getting there by Train:** * To Station: Driebergen-Zeist https://maps.app.goo.gl/1o211iUUR7ZzWZAq8 **Getting there by Car:** * P+R Driebergen-Zeist: Stationsweg 15B, Driebergen-Rijsenburg (payed) https://maps.app.goo.gl/Rzkus3PV1cXaiBV89 **Note:** * Please **pay a small fee (3 euro)** to help us cover the (increased) yearly Meetup contribution of 240 euro. We'll ask you to pay before the start of the hike (can be on the day itself). No refunds, but in the unlikely event that hike would be cancelled and you already paid, you don't need to pay for your next hike. Thank you so much! Use the **safe link** here: https://betaalverzoek.rabobank.nl/betaalverzoek/?id=cqlYWv_MTpSjp2VkROXWhA * Keep in mind that the hike can be canceled when the weather is very bad (**always check the event before you go**). * If you RSVP 'yes' we expect you to show-up. Please do not cancel less than 24 hours before the hike. **No-shows** will lead to your removal from the group. Thanks for the understanding. * By signing up for this event, you agree to release the organizers from any responsibility and liability in all claims. As the participation is strictly voluntary and you freely choose to join, it is the responsibility of individuals participating to ensure that they are fit enough and have adequate coverage to protect themselves.

Was always curious about Lockpicking? Join our social Lockpicking fun event - a casual, beginner-friendly drop-in workshop at [Boefzak](https://www.instagram.com/boefzakamsterdam/)! Learn a new skillset, get to know how a common lock works, and remember to always wield new skills ethically! A wide variety of locks and lock-picking tools will be waiting for you. But opening locks could be much more interesting, when you can get some **l00t**! Test your skills on dozens of **treasure boxes** filled with l00t and rewards. What’s inside? There’s only one way to find out. **No experience needed**. Lockpicks and tools you will get during the event. Just bring a good mood and enjoy the challenge. **[!]IMPORTANT[!]** Due to platform sign-up limitations, if no places are left, use this [https://luma.com/sprgzcbp](https://luma.com/sprgzcbp) to register.

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This is a public event. https://www.nesko.nl Please WhatsApp your meetup organisor for your confirmation!

Couldn't make Knowledge? Or want to debrief with fellow attendees? Join us for a Knowledge '26 recap, insights sharing, a couple rounds of golf, and fun at Topgolf. As always, drinks and food will be provided. More details to come — mark your calendar, RSVP, and save your spot today!

Want to be a speaker? submit your talk to our Call for Presenters!!! https://sessionize.com/cbus-hug-2026/

It feels like we just saw each other 🤷. Join members of the local design and UX community for our monthly breakfast. For May we’re stopping in for Rooh’s popup breakfast/cafe concept. You know someone is getting the lobster yuzu croissant, and that’s not even the prettiest thing on the menu!.

**Improving Office in Franklinton** Physical location: Improving Office 330 Rush Alley Suite #150 Columbus, OH 43215 Schedule: 6:00 p.m.: Socialize, eat, and drink. Improving will be providing pizza and beverages. 6:30 to 8:00 pm. Main meeting and presentation(s). Topic: This month Chris Pazsint will be talking about Agentic Coding. How does one use CLI Based Agents, and Agentic IDEs such as Cursor, Kiro, Antigravity? How to include agentic coding plugins for IDEs you already love such as Visual Studio Code. We meet on the last Monday of each Month. Presentations are given by members and friends of this group. If you would like to do a presentation (small or large) on a python topic, please contact Central OH Python at centralohpython@gmail.com

Join us for an engaging panel discussion on **AI Agentic Coding** and how autonomous AI systems are transforming the way software is built. Experts in AI, software engineering, and developer tools will share insights on how agentic AI—systems that can plan, reason, and execute coding tasks—is reshaping modern development workflows. The discussion will cover topics such as AI-assisted development, productivity gains, challenges around reliability and governance, and what the future of software engineering may look like with AI agents as collaborators. Whether you’re a developer, tech leader, or AI enthusiast, this session is a great opportunity to learn, ask questions, and explore how agentic AI is redefining coding

Join other experienced and aspiring agile coaches and professionals to: * develop and practice your coaching skills in a peer-to-peer environment * share current successes and challenges in your work environment and get support from each other * learn from each other, build better relationships and experiment with new ideas ***NOTE:*** Pre-registration is required for this event. **Please arrive 10 minutes early** to check in at the security desk.

**Latest Dojo Location!** **Knotty Pine Brewing** 1765 W 3rd Ave, Columbus, OH 43212 We're going to try a new dojo location for a few weeks and see how it works Dojos are informal Python group study sessions where everyone interested in Python gathers to learn about Python, help others with Python, or just hang out. Everyone is welcome from Python beginners to experts. Bringing a laptop is encouraged (we'll have extension cords and power strips). If there's something you want to learn leave a comment on this invite so we can plan ahead. We're looking for speakers for our Monthly Meetups! Fill out the form if you are interested in presenting to the Python Community. https://forms.gle/ehSfUAC2WgR34Crq9