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Karthik Narasimhan

28 accepted papers

2026

$\tau$-Knowledge: Evaluating Conversational Agents over Unstructured Knowledge

ICML 2026poster

Conversational agents are increasingly deployed in knowledge-intensive settings, where correct behavior depends on acquiring and applying domain-specific knowledge from large, proprietary, and unstructured corpora during live interactions with users. Yet most existing benchmarks evaluate retrieval o…

Cited by 0SourceScholar
2026

$\tau$-Voice: Benchmarking Full-Duplex Voice Agents on Real-World Domains

ICML 2026poster

Full-duplex voice agents—systems that listen and speak simultaneously—are rapidly moving from research to production. However, existing evaluations address conversational dynamics and task completion in isolation. We introduce $\tau$-voice, a benchmark for evaluating voice agents on grounded tasks w…

Cited by 9SourceScholar
2026

$\tau^2$-Bench: Evaluating Conversational Agents in a Dual-Control Environment

ICML 2026oral

Existing benchmarks for conversational AI agents simulate *single-control* environments, where only the AI agent can use tools to interact with the world, while the user remains a passive information provider. This differs from real-world scenarios like technical support, where users need to activel…

Cited by 0SourceScholar
2026

Retaining by Doing: The Role of On-Policy Data in Mitigating Forgetting

ICML 2026poster

Adapting language models (LMs) to new tasks via post-training carries the risk of degrading existing capabilities -- a phenomenon classically known as catastrophic forgetting. In this paper, toward identifying guidelines for mitigating this phenomenon, we systematically compare the forgetting patter…

Cited by 0SourceScholar
2025

LoRA Soups: Merging LoRAs for Practical Skill Composition Tasks

COLING 2025industry

Low-Rank Adaptation (LoRA) is a popular technique for parameter-efficient fine-tuning of Large Language Models (LLMs). We study how different LoRA modules can be merged to achieve skill composition—testing the performance of the merged model on a target task that involves combining multiple skills,…

2024

InstructEval: Systematic Evaluation of Instruction Selection Methods

NAACL 2024findings

In-context learning (ICL) performs tasks by prompting a large language model (LLM) using an instruction and a small set of annotated examples called demonstrations. Recent work has shown that precise details of the inputs used in the ICL prompt significantly impact performance, which has incentivize…

2024

QualEval: Qualitative Evaluation for Model Improvement

NAACL 2024long

Quantitative evaluation metrics have been pivotal in gauging the advancements of AI systems like large language models (LLMs).However, due to the intricate nature of real-world tasks, a single scalar to quantify and compare performance trivializes the fine-grained nuances of model behavior. Addition…

Cited by 3SourcePDFScholar
2024

Referral Augmentation for Zero-Shot Information Retrieval

ACL 2024findings

We propose Referral-Augmented Retrieval (RAR), a simple technique that concatenates document indices with referrals: text from other documents that cite or link to the given document. We find that RAR provides significant performance gains for tasks across paper retrieval, entity retrieval, and open…

2023

PruMUX: Augmenting Data Multiplexing with Model Compression

ACL 2023findings

As language models increase in size by the day, methods for efficient inference are critical to leveraging their capabilities for various applications. Prior work has investigated techniques like model pruning, knowledge distillation, and data multiplexing to increase model throughput without sacrif…

2022

CARETS: A Consistency And Robustness Evaluative Test Suite for VQA

ACL 2022long

We introduce CARETS, a systematic test suite to measure consistency and robustness of modern VQA models through a series of six fine-grained capability tests. In contrast to existing VQA test sets, CARETS features balanced question generation to create pairs of instances to test models, with each pa…

2022

When is BERT Multilingual? Isolating Crucial Ingredients for Cross-lingual Transfer

NAACL 2022long

While recent work on multilingual language models has demonstrated their capacity for cross-lingual zero-shot transfer on downstream tasks, there is a lack of consensus in the community as to what shared properties between languages enable such transfer. Analyses involving pairs of natural languages…

2021

Accelerating Safe Reinforcement Learning with Constraint-mismatched Baseline Policies

ICML 2021spotlight

We consider the problem of reinforcement learning when provided with (1) a baseline control policy and (2) a set of constraints that the learner must satisfy. The baseline policy can arise from demonstration data or a teacher agent and may provide useful cues for learning, but it might also be sub-o…

Cited by 26SourcePDFScholar
2021

Grounding Language to Entities and Dynamics for Generalization in Reinforcement Learning

ICML 2021spotlight

We investigate the use of natural language to drive the generalization of control policies and introduce the new multi-task environment Messenger with free-form text manuals describing the environment dynamics. Unlike previous work, Messenger does not assume prior knowledge connecting text and state…

2021

Improving Dialog Systems for Negotiation with Personality Modeling

ACL 2021long

In this paper, we explore the ability to model and infer personality types of opponents, predict their responses, and use this information to adapt a dialog agent’s high-level strategy in negotiation tasks. Inspired by the idea of incorporating a theory of mind (ToM) into machines, we introduce a pr…

2021

Learning Rewards From Linguistic Feedback

AAAI 2021technical

We explore unconstrained natural language feedback as a learning signal for artificial agents. Humans use rich and varied language to teach, yet most prior work on interactive learning from language assumes a particular form of input (e.g., commands). We propose a general framework which does not ma…

2021

Reading and Acting while Blindfolded: The Need for Semantics in Text Game Agents

NAACL 2021long

Text-based games simulate worlds and interact with players using natural language. Recent work has used them as a testbed for autonomous language-understanding agents, with the motivation being that understanding the meanings of words or semantics is a key component of how humans understand, reason,…

Cited by 28SourcePDFScholar
2021

Self-Attention Networks Can Process Bounded Hierarchical Languages

ACL 2021long

Despite their impressive performance in NLP, self-attention networks were recently proved to be limited for processing formal languages with hierarchical structure, such as Dyck-k, the language consisting of well-nested parentheses of k types. This suggested that natural language can be approximated…

2021

Universal Adversarial Attacks with Natural Triggers for Text Classification

NAACL 2021long

Recent work has demonstrated the vulnerability of modern text classifiers to universal adversarial attacks, which are input-agnostic sequences of words added to text processed by classifiers. Despite being successful, the word sequences produced in such attacks are often ungrammatical and can be eas…

2020

Calibration, Entropy Rates, and Memory in Language Models

ICML 2020poster

Building accurate language models that capture meaningful long-term dependencies is a core challenge in natural language processing. Towards this end, we present a calibration-based approach to measure long-term discrepancies between a generative sequence model and the true distribution, and use the…

Cited by 46SourcePDFScholar
2020

Evolving Graphical Planner: Contextual Global Planning for Vision-and-Language Navigation

NeurIPS 2020poster

The ability to perform effective planning is crucial for building an instruction-following agent. When navigating through a new environment, an agent is challenged with (1) connecting the natural language instructions with its progressively growing knowledge of the world; and (2) performing long-ran…

Cited by 95SourcePDFScholar
2020

Multimodal Graph Networks for Compositional Generalization in Visual Question Answering

NeurIPS 2020poster

Compositional generalization is a key challenge in grounding natural language to visual perception. While deep learning models have achieved great success in multimodal tasks like visual question answering, recent studies have shown that they fail to generalize to new inputs that are simply an unsee…

2020

Projection-Based Constrained Policy Optimization

ICLR 2020poster

We consider the problem of learning control policies that optimize a reward function while satisfying constraints due to considerations of safety, fairness, or other costs. We propose a new algorithm - Projection-Based Constrained Policy Optimization (PCPO), an iterative method for optimizing polici…

Cited by 307SourceScholar
2020

Towards Unique and Informative Captioning of Images

ECCV 2020poster

Despite considerable progress, state of the art image captioning models produce generic captions, leaving out important image details. Furthermore, these systems may even misrepresent the image in order to produce a simpler caption consisting of common concepts. In this paper, we first analyze both…

2019

A Generalized Algorithm for Multi-Objective Reinforcement Learning and Policy Adaptation

NeurIPS 2019poster

We introduce a new algorithm for multi-objective reinforcement learning (MORL) with linear preferences, with the goal of enabling few-shot adaptation to new tasks. In MORL, the aim is to learn policies over multiple competing objectives whose relative importance (preferences) is unknown to the agent…

2017

Constructing sub-word units for spoken term detection

ICASSP 2017accepted

Spoken term detection, especially of out-of-vocabulary (OOV) keywords, benefits from the use of sub-word systems. We experiment with different language-independent approaches to sub-word unit generation, generating both syllable-like and morpheme-like units, and demonstrate how the performance of sy…

Cited by 0SourceScholar
2015

JUMP-Means: Small-Variance Asymptotics for Markov Jump Processes

ICML 2015poster

Markov jump processes (MJPs) are used to model a wide range of phenomenon from disease progression to RNA path folding. However, existing methods suffer from a number of shortcomings: degenerate trajectories in the case of ML estimation of parametric models and poor inferential performance in the ca…

Cited by 11SourcePDFScholar