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Andrew Lee

16 accepted papers

2026

Decomposing Query-Key Feature Interactions Using Contrastive Covariances

ICML 2026poster

Despite the central role of attention heads in Transformers, we lack tools to understand why a model attends to a particular token. To address this, we study the query-key (QK) space -- the bilinear joint embedding space between queries and keys. We present a contrastive covariance method to decompo…

Cited by 0SourceScholar
2026

Into the Rabbit Hull: From Task-Relevant Concepts in DINO to Minkowski Geometry

ICLR 2026poster

DINOv2 sees the world well enough to guide robots and segment images, but we still do not know what it sees. We conduct the first comprehensive analysis of DINOv2’s representational structure using overcomplete dictionary learning, extracting over 32,000 visual concepts in what constitutes the large…

Cited by 0SourceScholar
2026

Look, Focus, Act: Efficient and Robust Robot Learning Via Human Gaze and Foveated Vision Transformers

ICRA 2026poster

Human vision is a highly active process driven by gaze, which directs attention to task-relevant regions through foveation, dramatically reducing visual processing. In contrast, robot learning systems typically rely on passive, uniform processing of raw camera images. In this work, we explore how in…

2026

VITA: Vision-to-Action Flow Matching Policy

ICLR 2026poster

Conventional flow matching and diffusion-based policies sample through iterative denoising from standard noise distributions (e.g., Gaussian), and require conditioning modules to repeatedly incorporate visual information during the generative process, incurring substantial time and memory overhead.…

Cited by 0SourcecodeScholar
2025

Active Vision Might Be All You Need: Exploring Active Vision in Bimanual Robotic Manipulation

ICRA 2025

Imitation learning has demonstrated significant potential in performing high-precision manipulation tasks using visual feedback. However, it is common practice in imitation learning for cameras to be fixed in place, resulting in issues like occlusion and limited field of view. Furthermore, cameras a

Cited by 33SourcecodeScholar
2025

Eeyore: Realistic Depression Simulation via Expert-in-the-Loop Supervised and Preference Optimization

ACL 2025finding

Large Language Models (LLMs) have been previously explored for mental healthcare training and therapy client simulation, but they still fall short in authentically capturing diverse client traits and psychological conditions. We introduce Eeyore , an 8B model optimized for realistic depression simul…

2025

How Does DPO Reduce Toxicity? A Mechanistic Neuron-Level Analysis

EMNLP 2025

Safety fine-tuning algorithms reduce harmful outputs in language models, yet their mechanisms remain under-explored. Direct Preference Optimization (DPO) is a popular choice of algorithm, but prior explanations—attributing its effects solely to dampened toxic neurons in the MLP layers—are incomplete

Cited by 0SourcePDFScholar
2025

ICLR: In-Context Learning of Representations

ICLR 2025poster

Recent work demonstrates that structured patterns in pretraining data influence how representations of different concepts are organized in a large language model’s (LLM) internals, with such representations then driving downstream abilities. Given the open-ended nature of LLMs, e.g., their ability t…

Cited by 7SourcePDFScholar
2024

A Mechanistic Understanding of Alignment Algorithms: A Case Study on DPO and Toxicity

ICML 2024oral

While alignment algorithms are commonly used to tune pre-trained language models towards user preferences, we lack explanations for the underlying mechanisms in which models become ``aligned'', thus making it difficult to explain phenomena like jailbreaks. In this work we study a popular algorithm,…

2024

Emergence of Hidden Capabilities: Exploring Learning Dynamics in Concept Space

NeurIPS 2024spotlight

Modern generative models demonstrate impressive capabilities, likely stemming from an ability to identify and manipulate abstract concepts underlying their training data. However, fundamental questions remain: what determines the concepts a model learns, the order in which it learns them, and its ab…

2024

Finding Increasingly Large Extremal Graphs with AlphaZero and Tabu Search

IJCAI 2024poster

This work proposes a new learning-to-search benchmark and uses AI to discover new mathematical knowledge related to an open conjecture of Erdos (1975) in extremal graph theory. The problem is to find graphs with a given size (number of nodes) that maximize the number of edges without having 3- or 4-…

Cited by 7SourcePDFScholar
2024

Has It All Been Solved? Open NLP Research Questions Not Solved by Large Language Models

COLING 2024main

Recent progress in large language models (LLMs) has enabled the deployment of many generative NLP applications. At the same time, it has also led to a misleading public discourse that “it’s all been solved.” Not surprisingly, this has, in turn, made many NLP researchers – especially those at the beg…

Cited by 9SourcePDFScholar
2024

Towards Algorithmic Fidelity: Mental Health Representation across Demographics in Synthetic vs. Human-generated Data

COLING 2024main

Synthetic data generation has the potential to impact applications and domains with scarce data. However, before such data is used for sensitive tasks such as mental health, we need an understanding of how different demographics are represented in it. In our paper, we analyze the potential of produc…

2021

Mechanical Search on Shelves using Lateral Access X-RAY

IROS 2021poster

Finding an occluded object in a lateral access environment such as a shelf or cabinet is a problem that arises in many contexts such as warehouses, retail, healthcare, shipping, and homes. While this problem, known as mechanical search, is well-studied in overhead access environments, lateral access…

Cited by 32SourceScholar
2021

Micromodels for Efficient, Explainable, and Reusable Systems: A Case Study on Mental Health

EMNLP 2021finding

Many statistical models have high accuracy on test benchmarks, but are not explainable, struggle in low-resource scenarios, cannot be reused for multiple tasks, and cannot easily integrate domain expertise. These factors limit their use, particularly in settings such as mental health, where it is di…

2019

Segmenting Unknown 3D Objects from Real Depth Images using Mask R-CNN Trained on Synthetic Data

ICRA 2019poster

The ability to segment unknown objects in depth images has potential to enhance robot skills in grasping and object tracking. Recent computer vision research has demonstrated that Mask R-CNN can be trained to segment specific categories of objects in RGB images when massive hand-labeled datasets are…

Cited by 233SourcecodeScholar