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Deepak Ramachandran

18 accepted papers

2026

Multi-Objective Preference Optimization: Improving Human Alignment of Generative Models

ICML 2026poster

Post-training LLMs with RLHF and preference optimization methods (e.g., DPO, IPO) has greatly improved alignment, yet these approaches assume a single objective. In reality, humans express multiple, often conflicting objectives, such as helpfulness and harmlessness, with no natural scalarization. We…

Cited by 0SourceScholar
2025

Erasing More Than Intended? How Concept Erasure Degrades the Generation of Non-Target Concepts

ICCV 2025poster

Concept erasure techniques have recently gained significant attention for their potential to remove unwanted concepts from text-to-image models. While these methods often demonstrate promising results in controlled settings, their robustness in real-world applications and suitability for deployment…

Cited by 0SourcePDFScholar
2025

Focus-N-Fix: Region-Aware Fine-Tuning for Text-to-Image Generation

CVPR 2025highlight

Text-to-image (T2I) generation has made significant advances in recent years, but challenges still remain in the generation of perceptual artifacts, misalignment with complex prompts, and safety. The prevailing approach to address these issues involves collecting human feedback on generated images,…

Cited by 2SourcePDFScholar
2025

Preference Adaptive and Sequential Text-to-Image Generation

ICML 2025poster

We address the problem of interactive text-to-image (T2I) generation, designing a reinforcement learning (RL) agent which iteratively improves a set of generated images for a user through a sequence of prompt expansions. Using human raters, we create a novel dataset of sequential preferences, which…

Cited by 0SourcePDFScholar
2025

Robust LLM Alignment via Distributionally Robust Direct Preference Optimization

NeurIPS 2025poster

A major challenge in aligning large language models (LLMs) with human preferences is the issue of distribution shift. LLM alignment algorithms rely on static preference datasets, assuming that they accurately represent real-world user preferences. However, user preferences vary significantly across…

Cited by 0SourceScholar
2025

What Secrets Do Your Manifolds Hold? Understanding the Local Geometry of Generative Models

ICLR 2025poster

Deep Generative Models are frequently used to learn continuous representations of complex data distributions by training on a finite number of samples. For any generative model, including pre-trained foundation models with Diffusion or Transformer architectures, generation performance can significan…

2024

Demystifying Embedding Spaces using Large Language Models

ICLR 2024poster

Embeddings have become a pivotal means to represent complex, multi-faceted information about entities, concepts, and relationships in a condensed and useful format. Nevertheless, they often preclude direct interpretation. While downstream tasks make use of these compressed representations, meaningfu…

Cited by 18SourcePDFScholar
2024

Prompt Expansion for Adaptive Text-to-Image Generation

ACL 2024long

Text-to-image generation models are powerful but difficult to use. Users craft specific prompts to get better images, though the images can be repetitive. This paper proposes the Prompt Expansion framework that helps users generate high-quality, diverse images with less effort. The Prompt Expansion…

2024

Rich Human Feedback for Text-to-Image Generation

CVPR 2024poster

Recent Text-to-Image (T2I) generation models such as Stable Diffusion and Imagen have made significant progress in generating high-resolution images based on text descriptions. However many generated images still suffer from issues such as artifacts/implausibility misalignment with text descriptions…

2024

TaskLAMA: Probing the Complex Task Understanding of Language Models

AAAI 2024technical

Structured Complex Task Decomposition (SCTD) is the problem of breaking down a complex real-world task (such as planning a wedding) into a directed acyclic graph over individual steps that contribute to achieving the task, with edges specifying temporal dependencies between steps. SCTD is an i…

Cited by 8SourcePDFScholar
2024

e-COP : Episodic Constrained Optimization of Policies

NeurIPS 2024poster

In this paper, we present the e-COP algorithm, the first policy optimization algorithm for constrained Reinforcement Learning (RL) in episodic (finite horizon) settings. Such formulations are applicable when there are separate sets of optimization criteria and constraints on a system's behavior. We…

Cited by 0SourcePDFScholar
2023

BoardgameQA: A Dataset for Natural Language Reasoning with Contradictory Information

NeurIPS 2023poster

Automated reasoning with unstructured natural text is a key requirement for many potential applications of NLP and for developing robust AI systems. Recently, Language Models (LMs) have demonstrated complex reasoning capacities even without any finetuning. However, existing evaluation for automated…

Cited by 39SourcePDFScholar
2023

KwikBucks: Correlation Clustering with Cheap-Weak and Expensive-Strong Signals

ICLR 2023poster

The unprecedented rate at which the sizes of machine learning (ML) models are growing necessitates novel approaches to enable efficient and scalable solutions. We contribute to this line of work by studying a novel version of the Budgeted Correlation Clustering problem (\bcc) where along with a limi…

Cited by 23SourcePDFScholar
2023

LAMBADA: Backward Chaining for Automated Reasoning in Natural Language

ACL 2023long

Remarkable progress has been made on automated reasoning with natural text, by using Large Language Models (LLMs) and methods such as Chain-of-Thought prompting and Selection-Inference. These techniques search for proofs in the forward direction from axioms to the conclusion, which suffers from a co…

Cited by 86SourcePDFScholar
2023

Pushing the Accuracy-Group Robustness Frontier with Introspective Self-play

ICLR 2023poster

Standard empirical risk minimization (ERM) training can produce deep neural network (DNN) models that are accurate on average but under-perform in under-represented population subgroups, especially when there are imbalanced group distributions in the long-tailed training data. Therefore, approaches…

Cited by 2SourcePDFScholar
2023

Using Domain Knowledge to Guide Dialog Structure Induction via Neural Probabilistic Soft Logic

ACL 2023long

Dialog Structure Induction (DSI) is the task of inferring the latent dialog structure (i.e., a set of dialog states and their temporal transitions) of a given goal-oriented dialog. It is a critical component for modern dialog system design and discourse analysis. Existing DSI approaches are often pu…

2022

FETA: A Benchmark for Few-Sample Task Transfer in Open-Domain Dialogue

EMNLP 2022main

Task transfer, transferring knowledge contained in related tasks, holds the promise of reducing the quantity of labeled data required to fine-tune language models. Dialogue understanding encompasses many diverse tasks, yet task transfer has not been thoroughly studied in conversational AI. This work…

2021

Which Linguist Invented the Lightbulb? Presupposition Verification for Question-Answering

ACL 2021long

Many Question-Answering (QA) datasets contain unanswerable questions, but their treatment in QA systems remains primitive. Our analysis of the Natural Questions (Kwiatkowski et al. 2019) dataset reveals that a substantial portion of unanswerable questions (~21%) can be explained based on the presenc…