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Department Events & Announcements

Events

• Oct

  8

  CS Seminar: Synthesizing Fine-grained State Checks for Curriculum Fuzzing (Kexin Pei)

  Department of Computer Science (CS)

  12:00 PM 3514, Mudd Hall ( formerly Seeley G. Mudd Library)

  EVENT DETAILS

  Wednesday / CS Seminar
  October 8th / 12:00 PM
  Hybrid / Mudd 3514

  Speaker
  Kexin Pei, University ofChicago

  Talk Title
  Synthesizing Fine-grained State Checks for Curriculum Fuzzing

  Abstract

  "Fuzzing enables many security applications, such as detecting vulnerabilities, confirming vulnerabilities by generating exploits, debugging system crashes and performance issues, and validating patches. While fuzzing essentially features a brute-force search, most research focuses on code reasoning to develop additional feedback that makes the search more efficient. For example, a typical feedback is code coverage, which serves as a proxy to measure progress towards reaching potential bugs, while being very easy to analyze and collect. However, such guidance is sometimes too sparse or indirect to reliably measure progress, especially when a long chain of implicit preconditions guards the specific bug. In contrast, more sophisticated feedbacks are often tailored for specific bug types and thus might not generalize to diverse bug types and programs.

  In this talk, I'll introduce our recent effort in building a code agent to reason about semantically meaningful progress-capturing predicates as fine-grained, curriculum feedback to improve fuzzing efficiency. These predicates, inserted as source-level instrumentation into the program, provide semantically meaningful checkpoints that both prune unpromising executions and reward incremental progress. By shifting the LLM’s role from end-to-end input-level generation to local predicate synthesis, we reduce the long-range reasoning burden on the model, while enabling verifiable predicate synthesis via symbolic execution. We show that our system, Locus, substantially improves the efficiency of eight state-of-the-art fuzzers, achieving up to 41.6× speedup in reaching target sites and discovering new previously unknown bugs. We also demonstrate that the same philosophy can facilitate the synthesis of performance-stressing predicates, enabling efficient performance testing."

  Biography
  Kexin Pei is a Neubauer Family Assistant Professor at the Department of Computer Science, The University of Chicago. He received my PhD at Department of Computer Science, Columbia University. He is broadly interested in Security, Software Engineering, and Machine Learning, focusing on developing data-driven program analysis to improve the security and reliability of both traditional and AI-based software systems. He gets most excited about developing machine learning models that can reason about program structure and behavior to precisely and efficiently analyze, detect, and fix software bugs and vulnerabilities.

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  TIME Wednesday, October 8, 2025 at 12:00 PM - 1:00 PM

  LOCATION 3514, Mudd Hall ( formerly Seeley G. Mudd Library)    map it

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  CONTACT Wynante R Charles    wynante.charles@northwestern.edu EMAIL

  CALENDAR Department of Computer Science (CS)

• Aug

  20

  Nathaniel Hejduk Qualifying Exam Presentation August 20: Navigating Mixed-Typed Migration with Profilers

  Department of Computer Science (CS)

  1:00 PM Mudd 3514, Mudd Hall ( formerly Seeley G. Mudd Library)

  EVENT DETAILS

  The component-by-component migration of a program from untyped to typed can trigger unintended performance degradations. When such a degradation occurs, typing well-chosen components can lessen the cost of type enforcement, while typing poorly chosen components can exacerbate it. In this talk, I examine whether off-the-shelf profiling tools deliver information that helps programmers navigate these migration choices effectively in Typed Racket.

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  TIME Thursday, August 20, 2026 at 1:00 PM - 4:00 PM

  LOCATION Mudd 3514, Mudd Hall ( formerly Seeley G. Mudd Library)    map it

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  CONTACT Jensen Smith    jensen.smith@northwestern.edu EMAIL

  CALENDAR Department of Computer Science (CS)

• Sep

  14

  Welcome & Breakfast for New McCormick PhD Students

  McCormick School of Engineering and Applied Science

  9:00 AM LR2, Technological Institute

  EVENT DETAILS

  Enjoy a welcome from Dean Christopher A. Schuh and other McCormick leaders, and receive a Northwestern Engineering T-shirt. A free breakfast on the Tech East Plaza will follow.

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  TIME Monday, September 14, 2026 at 9:00 AM - 10:30 AM

  LOCATION LR2, Technological Institute    map it

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  CONTACT Andi Joppie    andi.joppie@northwestern.edu EMAIL

  CALENDAR McCormick School of Engineering and Applied Science

• Sep

  22

  Welcome & Luncheon for New Full-time Graduate Students

  McCormick School of Engineering and Applied Science

  11:00 AM Ryan Family Auditorium, Technological Institute

  EVENT DETAILS

  Enjoy a welcome from Dean Christopher A. Schuh and other McCormick leaders, and receive a Northwestern Engineering T-shirt. A free lunch on the Tech East Plaza will follow.

  Register Now

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  TIME Tuesday, September 22, 2026 at 11:00 AM - 12:30 PM

  LOCATION Ryan Family Auditorium, Technological Institute    map it

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  CONTACT Andi Joppie    andi.joppie@northwestern.edu EMAIL

  CALENDAR McCormick School of Engineering and Applied Science

• Sep

  24

  Bagel Thursday + Discussion

  Department of Computer Science (CS)

  9:00 AM 3514, Mudd Hall ( formerly Seeley G. Mudd Library)

  EVENT DETAILS

  tba

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  TIME Thursday, September 24, 2026 at 9:00 AM - 11:00 AM

  LOCATION 3514, Mudd Hall ( formerly Seeley G. Mudd Library)    map it

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  CONTACT Wynante R Charles    wynante.charles@northwestern.edu EMAIL

  CALENDAR Department of Computer Science (CS)

• Sep

  28

  CS Seminar

  Department of Computer Science (CS)

  12:00 PM 3514, Mudd Hall ( formerly Seeley G. Mudd Library)

  EVENT DETAILS

  Monday / CS Seminar
  September 28 / 12:00 PM
  Hybrid / Mudd 3514

  Speaker
  TBA

  Talk Title
  TBA

  Abstract
  TBA

  Biography
  TBA

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  TIME Monday, September 28, 2026 at 12:00 PM - 1:00 PM

  LOCATION 3514, Mudd Hall ( formerly Seeley G. Mudd Library)    map it

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  CONTACT Wynante R Charles    wynante.charles@northwestern.edu EMAIL

  CALENDAR Department of Computer Science (CS)

• Oct

  5

  CS Seminar: Formal Relational Equivalence for SQL, GenAI, and Beyond (Brian Suchy)

  Department of Computer Science (CS)

  12:00 PM 3514, Mudd Hall ( formerly Seeley G. Mudd Library)

  EVENT DETAILS

  Monday / CS Seminar
  October 5 / 12:00 PM
  Hybrid / Mudd 3514

  Speaker
  Brian Suchy, Software Engineer Google DeepMind

  Talk Title
  Formal Relational Equivalence for SQL, GenAI, and Beyond

  Abstract
  Verifying that complex query rewrites from database optimizers or AI-driven generators preserve exact bag semantics under three-valued logic is an NP-hard challenge. To address this, we present an MLIR-native compiler framework that formally reasons about relational algebra. By decoupling query semantics from specific execution engines and lowering queries into a unified Relational Algebra Intermediate Representation, our language-agnostic methodology definitively proves semantic equivalence across all possible database states.

  The core of the presentation will deep-dive into our multi-tiered proving architecture, which synthesizes several advanced academic methodologies. First, we utilize E-Graphs and Equality Saturation to rapidly explore the equivalence space and detect structural congruence between query abstract syntax trees using fast, algebraic rewrite rules. Second, we employ Semiring Arithmetic, treating relational algebra as expressions over K-relations to leverage algebraic simplification and canonical forms under semiring laws. Finally, we implement a First-Order Logic and SMT translation path, lowering Relational Algebra into Relational Calculus and then into First-Order Logic to evaluate constraints and domain-specific axioms using parallel solvers like Z3 and CVC5, which either formally proves equivalence or synthesizes concrete counter-examples.

  Finally, we will discuss the practical implications of combining these formal mathematical methods with modern compiler design. Attendees will leave with a comprehensive understanding of how bridging database theory, equality saturation, and SMT solving can create robust solutions for verifying query optimizers, enforcing semantic correctness, and validating automated SQL generation at scale.

  Biography
  Brian Suchy is a Software Engineer within Google DeepMind.
  In his time at Google he has worked on F1 Query (Google's internal SQL query engine), hardware development, and (of course) AI.
  Prior to joining Google, Brian received his PhD student at Northwestern University, advised by Peter Dinda, with a focus on hardware/software codesign and memory management.

  Research Interests: Artificial Intelligence, Query Processing and Formal Logic

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  TIME Monday, October 5, 2026 at 12:00 PM - 1:00 PM

  LOCATION 3514, Mudd Hall ( formerly Seeley G. Mudd Library)    map it

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  CONTACT Wynante R Charles    wynante.charles@northwestern.edu EMAIL

  CALENDAR Department of Computer Science (CS)

• Oct

  29

  Bagel Thursday + Discussion

  Department of Computer Science (CS)

  9:00 AM 3514, Mudd Hall ( formerly Seeley G. Mudd Library)

  EVENT DETAILS

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  TIME Thursday, October 29, 2026 at 9:00 AM - 11:00 AM

  LOCATION 3514, Mudd Hall ( formerly Seeley G. Mudd Library)    map it

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  CONTACT Wynante R Charles    wynante.charles@northwestern.edu EMAIL

  CALENDAR Department of Computer Science (CS)

• Nov

  19

  Bagel Thursday + Discussion

  Department of Computer Science (CS)

  9:00 AM 3514, Mudd Hall ( formerly Seeley G. Mudd Library)

  EVENT DETAILS

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  TIME Thursday, November 19, 2026 at 9:00 AM - 11:00 AM

  LOCATION 3514, Mudd Hall ( formerly Seeley G. Mudd Library)    map it

  ADD TO CALENDAR

  CONTACT Wynante R Charles    wynante.charles@northwestern.edu EMAIL

  CALENDAR Department of Computer Science (CS)