Publications
Our teams aspire to make discoveries that impact everyone, and core to our approach is sharing our research and tools to fuel progress in the field.
Our teams aspire to make discoveries that impact everyone, and core to our approach is sharing our research and tools to fuel progress in the field.
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1 - 15 of 11092 publications
CrossCheck: Input Validation for WAN Control Systems
Rishabh Iyer
Isaac Keslassy
Sylvia Ratnasamy
Networked Systems Design and Implementation (NSDI) (2026) (to appear)
Preview abstract
We present CrossCheck, a system that validates inputs to the Software-Defined Networking (SDN) controller in a Wide Area Network (WAN). By detecting incorrect inputs—often stemming from bugs in the SDN control infrastructure—CrossCheck alerts operators before they trigger network outages.
Our analysis at a large-scale WAN operator identifies invalid inputs as a leading cause of major outages, and we show how CrossCheck would have prevented those incidents. We deployed CrossCheck as a shadow validation system for four weeks in a production WAN, during which it accurately detected the single incident of invalid inputs that occurred while sustaining a 0% false positive rate under normal operation, hence imposing little additional burden on operators. In addition, we show through simulation that CrossCheck reliably detects a wide range of invalid inputs (e.g., detecting demand perturbations as small as 5% with 100% accuracy) and maintains a near-zero false positive rate for realistic levels of noisy, missing, or buggy telemetry data (e.g., sustaining zero false positives with up to 30% of corrupted telemetry data).
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AI coding assistants are rapidly becoming integral to modern software development. A key challenge in this space is the continual need to migrate and modernize codebases in response to evolving software ecosystems. Traditionally, such migrations have relied on rule-based systems and human intervention. With the advent of powerful large language models (LLMs), AI-driven agentic frameworks offer a promising alternative—but their effectiveness remains underexplored. In this paper, we introduce FreshBrew, a novel benchmark for evaluating AI-based agentic frameworks on project-level Java migrations. We benchmark several such frameworks, powered by state-of-the-art LLMs, and compare their performance against established rule-based tools. Our evaluation of AI agents on this benchmark of 228 repositories shows that the top-performing model, Gemini 2.5 Flash, can successfully migrate 56.5% of projects to JDK 17. Our empirical analysis reveals novel insights into the critical strengths and limitations of current agentic approaches, offering actionable insights into their real-world applicability. By releasing FreshBrew publicly upon acceptance, we aim to facilitate rigorous, reproducible evaluation and catalyze progress in AI-driven codebase modernization.
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`It’s still abuse’: Community attitudes and perceptions on AI-generated image-based sexual abuse
Nicola Henry
Gemma Beard
Lisa Given
Information, Communication, & Society (2026)
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There are growing concerns about AI-generated image-based sexual abuse (AI-IBSA), also known as nonconsensual sexualized ′deepfakes.′ Empirical research on AI-IBSA, however, remains very limited. This study surveyed 7231 respondents across Australia, the United Kingdom, and the United States to investigate community attitudes and perceptions on AI-IBSA. Through a vignette study, we explored the relationship between public familiarity with AI-IBSA, normative concerns about consent, and context-dependent judgments that vary based on the target's identity relational status, and how the content was used. Our findings reveal strong condemnation of AI-IBSA, yet respondents demonstrated low familiarity with the technology and their views varied depending on particular contexts. AI-IBSA targeting intimate partners was viewed as more unacceptable than targeting celebrities, and content created solely for personal use was seen as less unacceptable than content intended for distribution. The study highlights the need for approaches that go beyond technical fixes and punitive measures, advocating for a multifaceted response that integrates ethical data governance, digital sexual literacy, and restorative justice approaches.
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Who Controls the Curriculum for AI? The Limits of Participatory Design for Educational AI
Michael Madaio
Learning Under Algorithmic Conditions, University of Minnesota Press (2026)
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Participatory design is a long-standing effort to shift control over technology design from technologists to users and communities impacted by technologies. For educational AI, this means involving students, families, teachers, and other stakeholders in shaping the design of AI systems. While promising, in this article, I situate the recent calls for participatory design of educational AI systems within a different historical tradition—that of contests over local control of educational curricula. I argue that approaches that attempt to steer the design and development of educational AI through participatory methods may inadvertently reproduce the history of political contestation of educational curricula, in ways that may privilege the most powerful communities, rather than those inequitably impacted. What might it look like to treat participatory AI design as a site for political contestation? How might these approaches avoid reproducing the same majoritarian tendencies that led to educational inequities in the first place?
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For many practical applications of quantum computing, the slowest and most costly steps involve coherently accessing classical data. We help address this challenge by applying mass production techniques, which can sometimes allow us to perform operations many times in parallel for a cost that is comparable to a single execution[1-3]. We combine existing mass-production results with modern approaches for loading classical data using ``quantum read-only memory.'' We show that quantum mass production techniques offer no benefit when we consider a cost model that focuses purely on the number of non-Clifford gates. However, analyzing the constant factors in a more nuanced cost model, we find that it may be possible to obtain a reduction in cost of an order or magnitude or more for a variety reasonably-sized fault-tolerant quantum algorithms. We present several applications of quantum mass-production techniques beyond naive parallelization, including a strategy for reducing the cost of serial calls to the same data loading step.
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How many T gates are needed to approximate an arbitrary n-qubit quantum state to within
a given precision ϵ? Improving prior work of Low, Kliuchnikov and Schaeffer, we show that the
optimal asymptotic scaling is Θ(sqrt{2^n log(1/ε)} + log(1/ε)) if we allow an unlimited number of ancilla qubits. We also show that this is the optimal T-count for implementing an arbitrary
diagonal n-qubit unitary to within error ϵ. We describe an application to batched synthesis of
single-qubit unitaries: we can approximate a tensor product of m = O(log log(1/ϵ)) arbitrary
single-qubit unitaries to within error ϵ with the same asymptotic T-count as is required to
approximate just one single-qubit unitary.
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ALF: Advertiser Large Foundation Model for Multi-Modal Advertiser Understanding
Sunny Rajagopalan
Alireza Golestaneh
Shubhra Chandra
Min Zhou
Jonathan Vronsky
Songbai Yan
2026
Preview abstract
We present ALF (Advertiser Large Foundation model), a multi-modal transformer architecture for understanding advertiser behavior and intent across text, image, video and structured data modalities. Through contrastive learning and multi-task optimization, ALF creates unified advertiser representations that capture both content and behavioral patterns. Our model achieves state-of-the-art performance on critical tasks including fraud detection, policy violation identification, and advertiser similarity matching. In production deployment, ALF reduces false positives by 90\% while maintaining 99.8\% precision on abuse detection tasks. The architecture's effectiveness stems from its novel combination of multi-modal transformations, intersample attention mechanism, spectrally normalized projections, and calibrated probabilistic outputs.
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Semantic data models express high-level business concepts and metrics, capturing the business logic needed to query a database correctly. Most data modeling solutions are built as layers above SQL query engines, with bespoke query languages or APIs. The layered approach means that semantic models can’t be used directly in SQL queries. This paper focuses on an open problem in this space – can we define semantic models in SQL, and make them naturally queryable in SQL?
In parallel, graph query is becoming increasingly popular, including in SQL. SQL/PGQ extends SQL with an embedded subset of the GQL graph query language, adding property graph views and making graph traversal queries easy.
We explore a surprising connection: semantic data models are graphs, and defining graphs is a data modeling problem. In both domains, users start by defining a graph model, and need query language support to easily traverse edges in the graph, which means doing joins in the underlying data.
We propose some useful SQL extensions that make it easier to use higher-level data model abstractions in queries. Users can define a “semantic data graph” view of their data, encapsulating the complex business logic required to query the underlying tables correctly. Then they can query that semantic graph model easily with SQL.
Our SQL extensions are useful independently, simplifying many queries – particularly, queries with joins. We make declared foreign key relationships usable for joins at query time – a feature that seems obvious but is notably missing in standard SQL.
In combination, these extensions provide a practical approach to extend SQL incrementally, bringing semantic modeling and graph query together with the relational model and SQL.
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A Computer Vision Problem in Flatland
Erin Connelly
Annalisa Crannell
Timothy Duff
Rekha R. Thomas
SIAM Journal on Applied Algebra and Geometry, 10 (2026), pp. 14-45
Preview abstract
When is it possible to project two sets of labeled points of equal cardinality lying in a pair of projective planes to the same image on a projective line? We give a complete answer to this question, obtaining the following results. We first show that such a pair of projections exist if and only if the two point sets are themselves images of a common point set in projective space. Moreover, we find that for generic pairs of point sets, a common projection exists if and only if their cardinality is at most seven. In these cases, we give an explicit description of the loci of projection centers that enable a common image.
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Consideration on CMAS arriving as discrete particles
Eric H. Jordan
Stephen Jordan
Hiram Diaz
Byung-gun Jun
(2025)
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Turbine contaminants known as CMAS mostly arrive as individual particles in a range of mineral compositions to turbine hot sections where they are deposited and within a small area can be treated as arriving at random locations as splats. By the time the particles reach the hot section the particle size maximum is believed to be 10 microns. Using a simplified heat transfer analysis suggests the arriving temperature will be the turbine inlet temperature. Using AFRL03 as a representative set of possible minerals, for most turbine inlet temperatures a mixture of melted and un-melted particles will arrive. There are 31 combinations of the 5 minerals of AFRL03 presenting a wide range of melting points experimentally investigated in this paper. As expected, combinations generally melt at lower temperatures than the highest melting mineral in each combination. The progression of conditions starting with the arrival of isolated individual minerals is modeled using monte carlo simulations and known materials from percolation theory. This allows understanding of the development of coverage fraction and potential for mineral mixing important to melt behavior as a function of normalized CMAS dose. Using the normalized CMAS dose it is also possible to comment on the likely relative fraction of coating life during which less than fully homogenized CMAS dominates behavior. It is noteworthy that 4 out of 5 minerals and 4 mineral combinations lack either calcium or silicon or both and also melt below 1300°C. Interaction in the early deposition stage involves non CMAS like chemistries.
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Score-based Causal Representation Learning: Linear and General Transformations
Abhishek Kumar
Emre Acarturk
Ali Tajer
Burak Varici
(JMLR) Journal of Machine Learning Research 2025 (2025)
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This paper addresses intervention-based causal representation learning (CRL) under a general nonparametric latent causal model and an unknown transformation that maps the latent variables to the observed variables. Linear and general transformations are investigated. The paper addresses both the identifiability and achievability aspects. Identifiability refers to determining algorithm-agnostic conditions that ensure the recovery of the true latent causal variables and the underlying latent causal graph. Achievability refers to the algorithmic aspects and addresses designing algorithms that achieve identifiability guarantees. By drawing novel connections between score functions (i.e., the gradients of the logarithm of density functions) and CRL, this paper designs a score-based class of algorithms that ensures both identifiability and achievability. First, the paper focuses on linear transformations and shows that one stochastic hard intervention per node suffices to guarantee identifiability. It also provides partial identifiability guarantees for soft interventions, including identifiability up to mixing with parents for general causal models and perfect recovery of the latent graph for sufficiently nonlinear causal models. Secondly, it focuses on general transformations and demonstrates that two stochastic hard interventions per node are sufficient for identifiability. This is achieved by defining a differentiable loss function whose global optima ensure identifiability for general CRL. Notably, one does not need to know which pair of interventional environments has the same node intervened. Finally, the theoretical results are empirically validated via experiments on structured synthetic data and image data.
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Life at the Boundary of Chemical Kinetics and Program Execution
Thomas Fischbacher
Physical Review E (2025)
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Abstract
This work introduces a generic quantitative framework for studying
processes that involve interactions of polymer sequences. Possible
applications range from quantitative studies of the reaction kinetics
of polymerization processes to explorations of the behavior of
chemical implementations of computational - including basic life-like
- processes. This way, we establish a bridge between thermodynamic and
computational aspects of systems that are defined in terms of sequence
interactions. As a by-product of these investigations, we clarify some
common confusion around the notion of ``autocatalysis''.
Using a Markov process model of polymer sequence composition and
dynamical evolution of the Markov process's parameters via an ODE that
arises when taking the double ``chemical'' many-particle limit as well
as ``rarefied interactions'' limit, this approach enables - for example
- accurate quantitative explorations of entropy generation in systems
where computation is driven by relaxation to thermodynamic equilibrium.
The computational framework internally utilizes the Scheme programming
language's intrinsic continuation mechanisms to provide nondeterministic
evaluation primitives that allow the user to specify example systems in
straight purely functional code, making exploration of all possible
relevant sequence composition constellations - which would be otherwise
tedious to write code for - automatic and hidden from the user.
As the original motivation for this work came from investigations into
emergent program evolution that arises in computational substrates of
the form discussed in recent work on ``Computational Life''
\cite{alakuijala2024computational}, a major focus of attention is on
giving a deeper explanation of key requirements for the possible
emergence of self-replicators especially in settings whose behavior is
governed by real world physics rather than ad-hoc rules that may be
difficult to implement in a physical system. A collection of fully
worked out examples elucidate how this modeling approach is
quantitatively related to Metropolis Monte Carlo based simulations as
well as exact or approximate analytic approaches, and how it can be
utilized to study a broad range of different systems. These examples
can also serve as starting points for further explorations.
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Bridging Sign and Spoken Languages: Pseudo GlossGeneration for Sign Language Translation
Trevor Cohn
Jianyuan Guo
Advances in Neural Information Processing Systems (NeurIPS) (2025)
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Sign Language Translation (SLT) aims to map sign language videos to spoken language text. A common approach leverages gloss annotations as an intermediate representation, decomposing SLT into two sub-tasks: video-to-gloss recognition and gloss-to-text translation. While effective, this paradigm relies on expert-annotated gloss labels, which are costly and increasingly unavailable in many datasets, limiting scalability.
To address this challenge, we propose a gloss-free pseudo gloss generation framework that eliminates the need for human-annotated glosses while preserving the structured intermediate representation. Specifically, we prompt a Large Language Model (LLM) with example text-gloss pairs to extract potential sign-related gloss words from the text by leveraging its in-context learning capability.
To mitigate the inherent misalignment between generated pseudo glosses and sign sequences in the video, we further refine their order by formulating the alignment as a weakly supervised learning problem.
With the reordered pseudo-glosses, additional alignment losses such as CTC can be incorporated to enhance supervision. We train our SLT model—comprising a vision encoder and a translator—under a three-stage pipeline, effectively bridging the gap between sign and spoken language.
Despite its simplicity, our approach outperforms previous state-of-the-art gloss-free frameworks across three SLT benchmarks and achieves competitive results with gloss-based methods.
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Permission Rationales in the Web Ecosystem: An Exploration of Rationale Text and Design Patterns
Yusra Elbitar
Soheil Khodayari
Marian Harbach
Gianluca De Stefano
Balazs Engedy
Giancarlo Pellegrino
Sven Bugiel
CHI 2025, ACM
Preview abstract
Modern web applications rely on features like camera and geolocation for personalized experiences, requiring user permission via browser prompts. To explain these requests, applications provide rationales—contextual information on why permissions are needed. Despite their importance, little is known about how rationales appear on the web or their influence on user decisions.
This paper presents the first large-scale study of how the web ecosystem handles permission rationales, covering three areas: (i) identifying webpages that use permissions, (ii) detecting and classifying permission rationales, and (iii) analyzing their attributes to understand their impact on user decisions. We examined over 770K webpages from Chrome telemetry, finding 3.6K unique rationale texts and 749 rationale UIs across 85K pages. We extracted key rationale attributes and assessed their effect on user behavior by cross-referencing them with Chrome telemetry data. Our findings reveal nine key insights, providing the first evidence of how different rationales affect user decisions.
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Automated Quantum Chemistry Code Generation with the $p^\daggerq$ Package
Lauren Koulias
Marcus Liebenthal
Run R. Li
Albert Eugene DePrince III
J. Phys. Chem. A 2025, 129, 29, 6679–6693 (2025)
Preview abstract
We present the most recent version of the \pq package, which is a Python library for generating equations and computer code for many-body quantum chemistry methods. Originally developed for prototyping single-reference electronic structure methods such as standard coupled-cluster (CC) and equation-of-motion (EOM) CC theory, the functionality in \pq has expanded to include boson operators, coupled fermion-boson operators, unitary cluster operators, non-particle-conserving EOM operators, spin tracing, multiple single-particle subspaces, and more. Additional developments allow for the generation of C++ and Python code that maximizes memory efficiency via careful analysis of contraction order and the reuse of intermediate tensor containers and minimizes floating-point operations by both contraction order and fusing like terms.
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