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Santu Rana

28 accepted papers

2025

ALPACA AGAINST VICUNA: Using LLMs to Uncover Memorization of LLMs

NAACL 2025long

In this paper, we investigate the overlooked impact of instruction-tuning on memorization in large language models (LLMs), which has largely been studied in base, pre-trained models. We propose a black-box prompt optimization method where an attacker LLM agent uncovers higher levels of memorization…

2025

Reproducing Kernel Banach Space Models for Neural Networks with Application to Rademacher Complexity Analysis

NeurIPS 2025poster

This paper explores the use of Hermite transform based reproducing kernel Banach space methods to construct exact or un-approximated models of feedforward neural networks of arbitrary width, depth and topology, including ResNet and Transformers networks, assuming only a feedforward topology, finite…

Cited by 0SourceScholar
2024

EMOTE: An Explainable Architecture for Modelling the Other through Empathy

IJCAI 2024poster

Empathy allows us to assume others are like us and have goals analogous to our own. This can also at times be applied to multi-agent games - e.g. Agent 1's attraction to green balls is analogous to Agent 2's attraction to red balls. Drawing inspiration from empathy, we propose EMOTE, a simple and…

2023

Gradient Descent in Neural Networks as Sequential Learning in Reproducing Kernel Banach Space

ICML 2023poster

The study of Neural Tangent Kernels (NTKs) has provided much needed insight into convergence and generalization properties of neural networks in the over-parametrized (wide) limit by approximating the network using a first-order Taylor expansion with respect to its weights in the neighborhood of the…

Cited by 3SourcePDFScholar
2023

Multi-weather Image Restoration via Domain Translation

ICCV 2023poster

Weather degraded conditions such as rain, haze, snow, etc. may degrade the performance of most computer vision systems. Therefore, effective restoration of multi-weather degraded images is an essential prerequisite for successful functioning of such systems. The current multi-weather image restorati…

Cited by 31PDFcodeScholar
2022

Expected Improvement for Contextual Bandits

NeurIPS 2022accept

The expected improvement (EI) is a popular technique to handle the tradeoff between exploration and exploitation under uncertainty. This technique has been widely used in Bayesian optimization but it is not applicable for the contextual bandit problem which is a generalization of the standard bandit…

Cited by 0SourcePDFScholar
2022

Human-AI Collaborative Bayesian Optimisation

NeurIPS 2022accept

Abstract Human-AI collaboration looks at harnessing the complementary strengths of both humans and AI. We propose a new method for human-AI collaboration in Bayesian optimisation where the optimum is mainly pursued by the Bayesian optimisation algorithm following complex computation, whilst getting…

Cited by 20SourcePDFScholar
2022

Momentum Adversarial Distillation: Handling Large Distribution Shifts in Data-Free Knowledge Distillation

NeurIPS 2022accept

Data-free Knowledge Distillation (DFKD) has attracted attention recently thanks to its appealing capability of transferring knowledge from a teacher network to a student network without using training data. The main idea is to use a generator to synthesize data for training the student. As the gener…

Cited by 33SourcePDFScholar
2022

Regret Bounds for Expected Improvement Algorithms in Gaussian Process Bandit Optimization

AISTATS 2022poster

The expected improvement (EI) algorithm is one of the most popular strategies for optimization under uncertainty due to its simplicity and efficiency. Despite its popularity, the theoretical aspects of this algorithm have not been properly analyzed. In particular, whether in the noisy setting, the E…

Cited by 3SourcePDFScholar
2022

TRF: Learning Kernels with Tuned Random Features

AAAI 2022technical

Random Fourier features (RFF) are a popular set of tools for constructing low-dimensional approximations of translation-invariant kernels, allowing kernel methods to be scaled to big data. Apart from their computational advantages, by working in the spectral domain random Fourier features expose th…

Cited by 0SourcePDFScholar
2022

Towards Effective and Robust Neural Trojan Defenses via Input Filtering

ECCV 2022poster

"Trojan attacks on deep neural networks are both dangerous and surreptitious. Over the past few years, Trojan attacks have advanced from using only a single input-agnostic trigger and targeting only one class to using multiple, input-specific triggers and targeting multiple classes. However, Trojan…

Cited by 6SourcePDFScholar
2022

Video Restoration Framework and Its Meta-Adaptations to Data-Poor Conditions

ECCV 2022poster

"Restoration of weather degraded videos is a challenging problem due to diverse weather conditions e.g., rain, haze, snow, etc. Existing works handle video restoration for each weather using a different custom-designed architecture. This approach has many limitations. First, a custom-designed archit…

2021

A New Representation of Successor Features for Transfer across Dissimilar Environments

ICML 2021spotlight

Transfer in reinforcement learning is usually achieved through generalisation across tasks. Whilst many studies have investigated transferring knowledge when the reward function changes, they have assumed that the dynamics of the environments remain consistent. Many real-world RL problems require tr…

Cited by 23SourcePDFScholar
2021

Bayesian Optimistic Optimisation with Exponentially Decaying Regret

ICML 2021spotlight

Bayesian optimisation (BO) is a well known algorithm for finding the global optimum of expensive, black-box functions. The current practical BO algorithms have regret bounds ranging from $\mathcal{O}(\frac{logN}{\sqrt{N}})$ to $\mathcal O(e^{-\sqrt{N}})$, where $N$ is the number of evaluations. This…

Cited by 0SourcePDFScholar
2021

High Dimensional Level Set Estimation with Bayesian Neural Network

AAAI 2021technical

Level Set Estimation (LSE) is an important problem with applications in various fields such as material design, biotechnology, machine operational testing, etc. Existing techniques suffer from the scalability issue, that is, these methods do not work well with high dimensional inputs. This paper pro…

2021

Kernel Functional Optimisation

NeurIPS 2021poster

Traditional methods for kernel selection rely on parametric kernel functions or a combination thereof and although the kernel hyperparameters are tuned, these methods often provide sub-optimal results due to the limitations induced by the parametric forms. In this paper, we propose a novel formulati…

2020

Accelerated Bayesian Optimisation through Weight-Prior Tuning

AISTATS 2020poster

Bayesian optimization (BO) is a widely-used method for optimizing expensive (to evaluate) problems. At the core of most BO methods is the modeling of the objective function using a Gaussian Process (GP) whose covariance is selected from a set of standard covariance functions. From a weight-space v…

2020

DeepCoDA: personalized interpretability for compositional health data

ICML 2020poster

Abstract Interpretability allows the domain-expert to directly evaluate the model’s relevance and reliability, a practice that offers assurance and builds trust. In the healthcare setting, interpretable models should implicate relevant biological mechanisms independent of technical factors like data…

2020

Distributionally Robust Bayesian Quadrature Optimization

AISTATS 2020poster

Bayesian quadrature optimization (BQO) maximizes the expectation of an expensive black-box integrand taken over a known probability distribution. In this work, we study BQO under distributional uncertainty in which the underlying probability distribution is unknown except for a limited set of its i.…

2020

Randomised Gaussian Process Upper Confidence Bound for Bayesian Optimisation

IJCAI 2020poster

In order to improve the performance of Bayesian optimisation, we develop a modified Gaussian process upper confidence bound (GP-UCB) acquisition function. This is done by sampling the exploration-exploitation trade-off parameter from a distribution. We prove that this allows the expected trade-off p…

2020

Sub-linear Regret Bounds for Bayesian Optimisation in Unknown Search Spaces

NeurIPS 2020poster

Bayesian optimisation is a popular method for efficient optimisation of expensive black-box functions. Traditionally, BO assumes that the search space is known. However, in many problems, this assumption does not hold. To this end, we propose a novel BO algorithm which expands (and shifts) the searc…

2019

Bayesian Optimization with Unknown Search Space

NeurIPS 2019poster

Applying Bayesian optimization in problems wherein the search space is unknown is challenging. To address this problem, we propose a systematic volume expansion strategy for the Bayesian optimization. We devise a strategy to guarantee that in iterative expansions of the search space, our method can…

2019

Multi-objective Bayesian optimisation with preferences over objectives

NeurIPS 2019poster

We present a multi-objective Bayesian optimisation algorithm that allows the user to express preference-order constraints on the objectives of the type objective A is more important than objective B. These preferences are defined based on the stability of the obtained solutions with respect to pref…

Cited by 76SourcePDFScholar
2018

Algorithmic Assurance: An Active Approach to Algorithmic Testing using Bayesian Optimisation

NeurIPS 2018poster

We introduce algorithmic assurance, the problem of testing whether machine learning algorithms are conforming to their intended design goal. We address this problem by proposing an efficient framework for algorithmic testing. To provide assurance, we need to efficiently discover scenarios where an a…

2018

Exploiting Strategy-Space Diversity for Batch Bayesian Optimization

AISTATS 2018poster

This paper proposes a novel approach to batch Bayesian optimisation using a multi-objective optimisation framework with exploitation and exploration forming two objectives. The key advantage of this approach is that it uses a suite of strategies to balance exploration and exploitation and thus can e…

Cited by 0SourcePDFScholar
2017

High Dimensional Bayesian Optimization with Elastic Gaussian Process

ICML 2017poster

Bayesian optimization is an efficient way to optimize expensive black-box functions such as designing a new product with highest quality or hyperparameter tuning of a machine learning algorithm. However, it has a serious limitation when the parameter space is high-dimensional as Bayesian optimizatio…

Cited by 142SourcePDFScholar
2017

Process-constrained batch Bayesian optimisation

NeurIPS 2017spotlight

Abstract Prevailing batch Bayesian optimisation methods allow all control variables to be freely altered at each iteration. Real-world experiments, however, often have physical limitations making it time-consuming to alter all settings for each recommendation in a batch. This gives rise to a unique…

Cited by 18SourcePDFScholar
2017

Regret Bounds for Transfer Learning in Bayesian Optimisation

AISTATS 2017poster

This paper studies the regret bound of two transfer learning algorithms in Bayesian optimisation. The first algorithm models any difference between the source and target functions as a noise process. The second algorithm proposes a new way to model the difference between the source and target as a G…

Cited by 44SourcePDFScholar