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Luca Zappella

14 accepted papers

2026

DSO: Direct Steering Optimization for Bias Mitigation

CVPR 2026

Generative models are often deployed to make decisions on behalf of users, such as vision-language models (VLMs) identifying which person in a room is a doctor to help visually impaired individuals. Yet, VLM decisions are influenced by the perceived demographic attributes of people in the input, whi

Cited by 0SourceScholar
2026

FlashRNN: Unlocking Parallel Training of Nonlinear RNNs for Large Language Models

ICLR 2026oral

Recurrent Neural Networks (RNNs) laid the foundation for sequence modeling, but their intrinsic sequential nature restricts parallel computation, creating a fundamental barrier to scaling. This has led to the dominance of parallelizable architectures like Transformers and, more recently, State Space…

Cited by 0SourcecodeScholar
2026

GenCtrl -- A Formal Controllability Toolkit for Generative Models

ICLR 2026poster

As generative models become ubiquitous, there is a critical need for fine-grained control over the generation process. Yet, while controlled generation methods from prompting to fine-tuning proliferate, a fundamental question remains unanswered: are these models truly controllable in the first place…

Cited by 0SourceScholar
2025

Bias after Prompting: Persistent Discrimination in Large Language Models

EMNLP 2025

A dangerous assumption that can be made from prior work on the bias transfer hypothesis (BTH) is that biases do not transfer from pre-trained large language models (LLMs) to adapted models. We invalidate this assumption by studying the BTH in causal models under prompt adaptations, as prompting is a

Cited by 0SourcePDFScholar
2025

Controlling Language and Diffusion Models by Transporting Activations

ICLR 2025spotlight

The increasing capabilities of large generative models and their ever more widespread deployment have raised concerns about their reliability, safety, and potential misuse. To address these issues, recent works have proposed to control model generation by steering model activations in order to effec…

2025

Is Your Model Fairly Certain? Uncertainty-Aware Fairness Evaluation for LLMs

ICML 2025poster

The recent rapid adoption of large language models (LLMs) highlights the critical need for benchmarking their fairness. Conventional fairness metrics, which focus on discrete accuracy-based evaluations (i.e., prediction correctness), fail to capture the implicit impact of model uncertainty (e.g., hi…

2025

LinEAS: End-to-end Learning of Activation Steering with a Distributional Loss

NeurIPS 2025poster

The growing use of generative models in daily life calls for efficient mechanisms to control their generation, to e.g. produce safe content or provide users with tools to explore style changes. Ideally, such mechanisms should require low volume of unpaired data (\ie without explicit preference), and…

Cited by 0SourceScholar
2025

Revisiting Uncertainty Quantification Evaluation in Language Models: Spurious Interactions with Response Length Bias Results

ACL 2025short

Uncertainty Quantification (UQ) in Language Models (LMs) is key to improving their safety and reliability. Evaluations often use metrics like AUROC to assess how well UQ methods (e.g., negative sequence probabilities) correlate with task correctness functions (e.g., ROUGE-L). We show that mutual bia…

2025

Understanding Input Selectivity in Mamba: Impact on Approximation Power, Memorization, and Associative Recall Capacity

ICML 2025poster

State-Space Models (SSMs), and particularly Mamba, have recently emerged as a promising alternative to Transformers. Mamba introduces input selectivity to its SSM layer (S6) and incorporates convolution and gating into its block definition. While these modifications do improve Mamba's performance ov…

Cited by 0SourcePDFScholar
2024

Whispering Experts: Neural Interventions for Toxicity Mitigation in Language Models

ICML 2024poster

An important issue with Large Language Models (LLMs) is their undesired ability to generate toxic language. In this work, we show that the neurons responsible for toxicity can be determined by their power to discriminate toxic sentences, and that toxic language can be mitigated by reducing their act…

Cited by 7SourcePDFScholar
2023

DUET: 2D Structured and Approximately Equivariant Representations

ICML 2023poster

Multiview Self-Supervised Learning (MSSL) is based on learning invariances with respect to a set of input transformations. However, invariance partially or totally removes transformation-related information from the representations, which might harm performance for specific downstream tasks that req…

2023

DeepPCR: Parallelizing Sequential Operations in Neural Networks

NeurIPS 2023poster

Parallelization techniques have become ubiquitous for accelerating inference and training of deep neural networks. Despite this, several operations are still performed in a sequential manner. For instance, the forward and backward passes are executed layer-by-layer, and the output of diffusion model…

Cited by 1SourcePDFScholar
2023

The Role of Entropy and Reconstruction in Multi-View Self-Supervised Learning

ICML 2023poster

The mechanisms behind the success of multi-view self-supervised learning (MVSSL) are not yet fully understood. Contrastive MVSSL methods have been studied through the lens of InfoNCE, a lower bound of the Mutual Information (MI). However, the relation between other MVSSL methods and MI remains uncle…