Publications (15)
No More Pesky Hyperparameters: Offline Hyperparameter Tuning for RL
Han Wang, Archit Sakhadeo, Adam White +7
The performance of reinforcement learning (RL) agents is sensitive to the choice of hyperparameters. In real-world settings like robotics or industrial control systems, however, te…
Private Protocols for U-Statistics in the Local Model and Beyond
James Bell, Aurélien Bellet, Adrià Gascón +1
In this paper, we study the problem of computing -statistics of degree , i.e., quantities that come in the form of averages over pairs of data points, in the local model of d…
Estimation methods for estimands using the treatment policy strategy; a simulation study based on the PIONEER 1 Trial
James Bell, Thomas Drury, Tobias Mütze +6
Estimands using the treatment policy strategy for addressing intercurrent events are common in Phase III clinical trials. One estimation approach for this strategy is retrieved dro…
Beyond COVID-19: Network science and sustainable exit strategies
James Bell, Ginestra Bianconi, David Butler +11
On May and , a two day workshop was held virtually, facilitated by the Beyond Center at ASU and Moogsoft Inc. The aim was to bring together leading scientists wi…
MPC-Friendly Commitments for Publicly Verifiable Covert Security
Nitin Agrawal, James Bell, Adrià Gascón +1
We address the problem of efficiently verifying a commitment in a two-party computation. This addresses the scenario where a party P1 commits to a value to be used in a subsequ…
Differentially Private Summation with Multi-Message Shuffling
Borja Balle, James Bell, Adria Gascon +1
In recent work, Cheu et al. (Eurocrypt 2019) proposed a protocol for -party real summation in the shuffle model of differential privacy with error and $Î(ε\sqr…
Improved Summation from Shuffling
Borja Balle, James Bell, Adria Gascon +1
A protocol by Ishai et al.\ (FOCS 2006) showing how to implement distributed -party summation from secure shuffling has regained relevance in the context of the recently propose…
TraceSecure: Towards Privacy Preserving Contact Tracing
James Bell, David Butler, Chris Hicks +1
Contact tracing is being widely employed to combat the spread of COVID-19. Many apps have been developed that allow for tracing to be done automatically based off location and inte…
Private Summation in the Multi-Message Shuffle Model
Borja Balle, James Bell, Adria Gascon +1
The shuffle model of differential privacy (Erlingsson et al. SODA 2019; Cheu et al. EUROCRYPT 2019) and its close relative encode-shuffle-analyze (Bittau et al. SOSP 2017) provide…
The Privacy Blanket of the Shuffle Model
Borja Balle, James Bell, Adria Gascon +1
This work studies differential privacy in the context of the recently proposed shuffle model. Unlike in the local model, where the server collecting privatized data from users can…
Differentially Private Health Tokens for Estimating COVID-19 Risk
David Butler, Chris Hicks, James Bell +2
In the fight against Covid-19, many governments and businesses are in the process of evaluating, trialling and even implementing so-called immunity passports. Also known as antibod…
Integrating Novelty Detection Capabilities with MSL Mastcam Operations to Enhance Data Analysis
Paul Horton, Hannah R. Kerner, Samantha Jacob +3
While innovations in scientific instrumentation have pushed the boundaries of Mars rover mission capabilities, the increase in data complexity has pressured Mars Science Laboratory…
The global economic impact of AI technologies in the fight against financial crime
James Bell
Is the rapid adoption of Artificial Intelligence a sign that creative destruction (a capitalist innovation process first theorised in 1942) is occurring? Although its theory sugges…
Amplification by Shuffling without Shuffling
Borja Balle, James Bell, Adrià Gascón
Motivated by recent developments in the shuffle model of differential privacy, we propose a new approximate shuffling functionality called Alternating Shuffle, and provide a protoc…
Time-Reversal of Coalescing Diffusive Flows and Weak Convergence of Localized Disturbance Flows
James Bell
We generalize the coalescing Brownian flow, aka the Brownian web, considered as a weak flow to allow varying drift and diffusivity in the constituent diffusion processes and call t…