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.

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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 11433 publications
Preview abstract Recent reports have highlighted how mobile apps share user location data with third parties, risking user privacy and platform trust. Although location data is highly sensitive, when users grant apps location access, they may not know the full extent to which it is used. We study how requiring Android apps to show a reason for location access could impact developers, users, and the platform. We surveyed 323 Android app developers and found most supported such a requirement. The majority said it would have a positive impact on user privacy, trust for apps, and trust for Android, where impact on user trust for Android correlated most strongly with support. Many developers also said the intervention would increase the number of users granting location access. Yet their open-ended comments also revealed consistent concerns, such as apps providing dishonest reasons and platform verification. To study the impact on user behavior, we conducted a randomized controlled experiment with 2579 US Android users. We tested how users' decisions to grant location access were impacted by app type, whether reasons were included in the requests, and the content of the reasons, including monetization. We did not find the reasons impacted users' decisions; decisions were instead driven by app type and demographics. Yet we did find the reasons could have a positive impact on user perception for the platform when the reasons did not include using data for ads. Our findings provide insights into developers' willingness to implement privacy-enhancing changes, and expose limits to improving user privacy by simply adding information to user interfaces. View details
Preview abstract The emergence of Agentic AI—autonomous systems capable of reasoning, decision-making, and multi-step execution—represents a paradigm shift in enterprise technology. Moving beyond simple generative tasks, these agents offer the potential to solve long-standing industry pain points, with over 90% of enterprises planning integration within the next three years. However, the transition from successful proof-of-concept (PoC) to a resilient, production-grade system presents significant hurdles. This article categorizes these challenges into three primary domains: Technical and Engineering Hurdles: Issues such as "entangled workflows" that complicate debugging, the struggle to maintain output quality and mitigate hallucinations, and the unpredictability caused by shifting underlying models or data sources. People, Process, and Ecosystem Hurdles: The high operational costs and unclear ROI of large models, the necessity of a new "Agent Ops" skillset, the complexity of integrating agents with disparate enterprise systems, and a rapidly evolving regulatory landscape. The Pace of Change and Security risks: The technical debt incurred by shifting software frameworks and the expanded attack surface created by autonomous agents. The article concludes that successful deployment requires a shift from informal "vibe-testing" to rigorous engineering discipline. By adopting code-first frameworks, establishing robust evaluation metrics (KPIs), and prioritizing functional deployment over theoretical optimization, organizations can effectively manage the lifecycle of Agentic AI and realize its transformative business value. View details
Platform Competition in the Autobidding World
Ariel Schvartzman
Andres Perlroth
Mingfei Zhao
Proceedings of the ACM Web Conference 2026, Association for Computing Machinery, New York, NY, USA, 87–98
Preview abstract We study the problem of auction design for advertising platforms that face strategic advertisers who are bidding across platforms. Each advertiser's goal is to maximize their total value or conversions while satisfying some constraint(s) across all the platforms they participates in. In this paper, we focus on advertisers with return-over-investment (henceforth, ROI) constraints, i.e. each advertiser is trying to maximize value while making sure that their ROI across all platforms is no less than some target value. An advertiser interacts with the platforms through autobidders -- for each platform, the advertiser strategically chooses a target ROI to report to the platform's autobidder, which in turn uses a uniform bid multiplier to bid on the advertiser's behalf on the queries owned by the given platform. Our main result is an auction comparator theorem that can be used to choose between different auction mechanisms by a revenue-maximizing platform operating in a competitive environment. Analogous to the Linkage Principle for interdependent values, our comparator demonstrates that, for a broad class of advertiser valuations, second-price auctions may sometimes generate higher revenue than first-price auctions. This contrasts sharply with the single-platform setting, where first-price auctions are optimal for both revenue and welfare. Our findings highlight the critical importance of considering inter-platform competition when designing optimal auctions. View details
Preview abstract Systems for escalating interactions from automated agents to human agents can create inefficiencies, for example, by transferring unstructured transcripts. An intermediary system can employ a generative artificial intelligence synthesis engine to process the context of an automated interaction upon an escalation trigger. The engine may analyze the dialogue transcript, user metadata, and the automated agent's internal state to perform semantic abstraction, diagnose potential failure points, and infer a possible resolution. The system can then generate a structured briefing for the human agent, which could include a concise summary, a failure diagnosis, or a recommended next action presented as an interactive element. This process may facilitate a more efficient handoff and contribute to an improved escalation workflow by providing the human agent with synthesized, contextual information. View details
Preview abstract One of the most exciting developments in the time series space over the last few years has been the advances in probabilistic forecasting capabilities, both in terms of modeling approaches and available tools. Yet adoption of probabilistic forecasting methods has been slow amongst the wider forecasting community, and data science teams and business stakeholders are missing out on the opportunities provided by more accurate characterization of the uncertainty, including their correlations. In this presentation, we will point out that most established point forecasting approaches can be easily augmented to produce distributional forecasts, making it very hard to distinguish between the two types of approaches in practice. The gravitation towards using a single number as a forecast due to its explainability and operability makes the concrete benefits and ROI of upgrading to probabilistic forecasting approaches ambiguous at best, thus contributing to the challenges with adopting the newer probabilistic models. We will then argue for a reframing of the probabilistic vs. point forecasting distinction, not in terms of modeling approaches and pipeline configurations, but as a fundamental first principles based distinction based on the available data and the use case requirements. Probabilistic forecasting should not be seen as an add-on to point forecasting, nor as an opportunity for an incremental improvement on uncertainty bounds. It should be clear that certain applications mandate probabilistic forecasting because point forecasting, no matter how accurate, will lead to wrong decision making. This distinction should be analogous to how the distinction between regression and classification use cases is defined, or the distinction between clustering and dimensionality reduction use cases is defined. We will also discuss possible criteria for this first principles based distinction between point forecasting use cases and probabilistic use cases, and argue for why such a reframing might be beneficial for practitioners and business users. This article aims to initiate a discussion on making probabilistic forecasting as a principle that is more accessible to practitioners and non-technical stakeholders; that it is not an improvement to point forecasts: it is a critical must-have for many (or most) business forecasting use cases. View details
Preview abstract 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. View details
Preview abstract Steinke [Ste25] recently asked the following intriguing open question: Can we solve the differentially private selection problem with nearly-optimal error by only (adaptively) invoking Gaussian mechanism on low-sensitivity queries? In this short note, we resolve this question positively. In particular, for a candidate set Y, we achieve error guarantee of O ̃ (log |Y|), which is within a factor of (log log |Y|)^O(1) of the exponential mechanism [MT07]. This improves on Steinke’s mechanism which achieves an error of O(log^{3/2} |Y|). View details
Preview abstract Browser fingerprinting is the practice of tracking users across the Web by collecting attributes from their devices and combining them to create unique identifiers. This practice poses major privacy risks to users, and more than a decade of research has quantified fingerprinting risks due to various attributes, leading browser developers to implement many privacy-enhancing changes. Early work used Shannon entropy to quantify risks. However, Shannon entropy can grow with dataset size, limiting the ability to compare datasets and results. Researchers then introduced normalized entropy as a measure for comparing browser fingerprinting datasets of different sizes and numerous works followed using normalized entropy for this purpose. We identify and address a resulting problem in the fingerprinting literature. We show normalized entropy is ill-suited to compare datasets of different sizes — it decreases as dataset size increases. We show this both analytically and empirically, leveraging a recently published dataset of browser attributes commonly used for fingerprinting. Given the unmet need for a better fingerprinting risk measure, we define a minimal set of desired properties for such a measure: scale-invariance, monotonicity and estimability. We then propose to use Tsallis entropy as a more interpretable fingerprinting risk measure. We evaluate Shannon, normalized, and Tsallis entropy with respect to the properties, and prove that only Tsallis entropy satisfies all of them. View details
Preview abstract Automating AI research differs from general software engineering due to computationally expensive evaluation (e.g., model training) and opaque performance attribution. Current LLM-based agents struggle here, often generating monolithic scripts that ignore execution costs and causal factors. We introduce MARS (Modular Agent with Reflective Search), a framework optimized for autonomous AI research. MARS relies on three pillars: (1) Budget-Aware Planning via cost-constrained Monte Carlo Tree Search (MCTS) to explicitly balance performance with execution expense; (2) Modular Construction, employing a "Design-Decompose-Implement" pipeline to manage complex research repositories; and (3) Comparative Reflective Memory, which addresses credit assignment by analyzing solution differences to distill high-signal insights. MARS achieves state-of-the-art performance among open-source frameworks on MLE-Bench under comparable settings, maintaining competitiveness with the global leaderboard's top methods. Furthermore, the system exhibits qualitative "Aha!" moments, where 63% of all utilized lessons originate from cross-branch transfer, demonstrating that the agent effectively generalizes insights across search paths. View details
Preview abstract Generative AI (GenAI) is evolving from standalone tools to interconnected ecosystems that integrate chatbots, cloud platforms, and third-party services. While this ecosystem model enables personalization and extended services, it also introduces complex information flows and amplifies privacy risks. Existing solutions focus on system-level protections, offering little support for users to make meaningful privacy choices. To address this gap, we conducted two vignette-based survey studies with 486 participants and a followup interview study with 16 participants. We also explored users’ needs and preferences for privacy choice design across both GenAI personalization and data-sharing. Our results reveal paradoxical patterns: participants sometimes trusted third-party ecosystems more for personalization but perceived greater control in first-party ecosystems when data was shared externally. We discuss design implications for privacy choice interfaces that enhance transparency, control, and trust in GenAI ecosystems. View details
Preview abstract Some artificial intelligence provisioning models that function as tools for human users or rely on labor arbitrage can present challenges for organizations, such as managing personnel rather than task outcomes and introducing data security risks. An architecture is described for an outcome-based synthetic labor market in which autonomous computational agents can be compensated based on verified task completion. The framework can leverage trusted execution environments to create secure hardware enclaves for processing sensitive data, which can render the data cryptographically inaccessible to a host system or agent provider. This approach can facilitate a secure, transactional market for autonomous professional execution, which may enable a shift from managing labor resources to procuring verified outcomes from a pool of specialized agents. View details
A large language model for complex cardiology care
Jack W O’Sullivan
Khaled Saab
Daniel K. Amponsah
Evaline Cheng
Yong Cheng
Emily Chu
Yaanik Desai
Aly Elezaby
Muhammad Fazal
Tasmeen Hussain
Sneha S. Jain
Daniel Seung Kim
Roy Lan
Jiwen Li
Wilson Tang
Natalie Tapaskar
Victoria Parikh
Ryan Sandoval
Gabriela Spencer-Bonilla
Bryan Wu
Kavita Kulkarni
Philip Mansfield
Juro Gottweis
Joelle Barral
Ryutaro Tanno
Sara Mahdavi
Euan Ashley
Nature Medicine (2026)
Preview abstract The scarcity of subspecialist medical expertise poses a considerable challenge for healthcare delivery. This issue is particularly acute in cardiology, where timely, accurate management determines outcomes. We explored the potential of Articulate Medical Intelligence Explorer (AMIE), a large language model-based experimental medical artificial intelligence system, to augment clinical decision-making in this challenging context. We conducted a randomized controlled trial comparing large language model-assisted care with the usual care of complex patients suspected of having a genetic cardiomyopathy, and we curated a real-world dataset of complex cases from a subspecialist cardiology practice. Nine participating general cardiologists were provided with access to both clinical text reports and raw diagnostic data—including electrocardiograms, echocardiograms, cardiac magnetic resonance imaging scans and cardiopulmonary exercise testing—and were randomized to manage these cases, either with or without assistance from AMIE. We developed a ten-domain evaluation rubric used by three blinded subspecialists to evaluate the quality of triage, diagnosis and management. In our randomized controlled trial with retrospective patient data, subspecialists favored large language model-assisted responses overall, and for the management plan and diagnostic testing domains, with the remaining domains considered a tie. Overall, subspecialists preferred AMIE-assisted cardiology assessments 46.7% of the time, compared with 32.7% for cardiologists alone (P = 0.02), with 20.6% rated as a tie. Subspecialists also quantified errors, extra and missing content, reasoning and potential bias. Cardiologists alone had more clinically significant errors (24.3% versus 13.1%, P = 0.033) and more missing content (37.4% versus 17.8%, P = 0.0021) than cardiologists assisted by AMIE. Lastly, cardiologists who used AMIE reported that AMIE helped their assessment more than half the time (57.0%) and saved time in 50.5% of cases. View details
Global monitoring of methane point sources using deep learning on hyperspectral radiance measurements from EMIT
Michelangelo Conserva
Alex Wilson
Anna Michalak
Phil Brodrick
Andrew Thorpe
Proceedings of the National Academy of Sciences (2026)
Preview abstract Anthropogenic methane (CH4) point sources are critical drivers of near-term climate forcing, safety hazards, and system inefficiencies. Global tracking with imaging spectroscopy is just becoming feasible, but still largely relies on manual tracking. Here we present the Methane Analysis and Plume Localization with EMIT (MAPL-EMIT) model, an end-to-end vision transformer framework that advances the state of the practice by directly utilizing the complete radiance spectrum from the Earth Surface Mineral Dust Source Investigation (EMIT) instrument to jointly retrieve methane enhancements across all pixels within a scene. This approach joins spectral information content - where the methane signature resides - with essential spatial context to significantly lower detection limits. MAPL-EMIT simultaneously supports quantification, plume delineation, and source localization, even for multiple overlapping plumes. The model was trained on 3.6 million physics-based synthetic plumes injected into global EMIT radiance data. Evaluation against synthetic observations confirms the model’s ability to identify plumes with high recall and precision and to capture weaker plumes relative to existing matched-filter approaches. On real-world benchmarks, MAPL-EMIT captures 79% of known hand-annotated NASA L2B plume complexes across a test set of 1084 EMIT granules, while identifying twice as many plausible plumes than identified by human analysts. Further validation against coincident airborne data, top-emitting landfills, and controlled release experiments confirms the models efficacy at identifying previously uncaptured sources. By incorporating model-generated metrics such as spectral fit scores and estimated noise levels, the framework can further limit false-positive rates. Overall, MAPL-EMIT enables high-throughput implementation on the full EMIT data catalog, shifting methane monitoring from labor-intensive workflows to a rapid, scalable paradigm for facility-level accountability. View details
Preview abstract In this paper we introduce \emph{OPO-CMDP}, the first policy optimization algorithm for stochastic Contextual Markov Decision Process (CMDPs) under general offline function approximation. We establish a high probability regret bound of $\widetilde{O}\left(H^4\sqrt{T|S||A|\log(|\mathcal{F}||\mathcal{P}|)}\right),$ where $S$ and $A$ denote the state and action spaces, $H$ the horizon length, $T$ the number of episodes, and $\mathcal{F}, \mathcal{P}$ the function classes used to approximate the losses and dynamics, respectively. This result improves the dependence on $|S|$ and $|A|$ compared to the previously known state-of-the-art bound of \citet*{DBLP:conf/nips/QianHS24}. Our analysis introduces sophisticated confidence bounds for stochastic policies that eliminate restrictive assumptions required in prior work. Our results demonstrate that simple policy optimization over optimistic model approximations can achieve better, near-optimal regret bound for CMDPs. View details
Preview abstract Using generative artificial intelligence with sensitive data may present challenges, as transmitting personally identifiable information or protected health information to third-party providers can introduce security risks, and some data masking techniques can reduce reasoning capabilities. A described system uses a proxy, masking layer that can intercept data within an enterprise's secure perimeter. This layer can substitute sensitive strings with persistent, structured semantic tokens that may be enriched with non-sensitive metadata hints to help preserve context. An external artificial intelligence can perform reasoning on this abstracted data, and its tokenized response can be re-hydrated into readable text on a client device (e.g., a smartphone, computer, or wearable device). This approach may allow third-party models to reason on proprietary information without direct access to the underlying plaintext data, which can assist organizations in managing data sovereignty while maintaining functional utility. View details
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