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Ali Modarressi

12 accepted papers

2026

Steering MoE LLMs via Expert (De)Activation

ICLR 2026poster

Mixture-of-Experts (MoE) in Large Language Models (LLMs) routes each token through a subset of specialized Feed-Forward Networks (FFN), known as experts. We present SteerMoE, a framework to steer MoE models by detecting and controlling behavior-associated experts. We detect key experts by comparing…

Cited by 0SourcecodeScholar
2026

With Argus Eyes: Assessing Retrieval Gaps via Uncertainty Scoring to Detect and Remedy Retrieval Blind Spots

ICML 2026poster

Reliable retrieval-augmented generation (RAG) systems depend fundamentally on the retriever’s ability to find relevant information. We show that neural retrievers used in RAG systems have blind spots, which we define as the failure to retrieve entities that are relevant to the query, but have low si…

Cited by 0SourceScholar
2025

Collapse of Dense Retrievers: Short, Early, and Literal Biases Outranking Factual Evidence

ACL 2025long

Dense retrieval models are commonly used in Information Retrieval (IR) applications, such as Retrieval-Augmented Generation (RAG). Since they often serve as the first step in these systems, their robustness is critical to avoid downstream failures. In this work, we repurpose a relation extraction da…

Cited by 0SourcePDFScholar
2025

ImpliRet: Benchmarking the Implicit Fact Retrieval Challenge

EMNLP 2025

Retrieval systems are central to many NLP pipelines, but often rely on surface-level cues such as keyword overlap and lexical semantic similarity. To evaluate retrieval beyond these shallow signals, recent benchmarks introduce reasoning-heavy queries; however, they primarily shift the burden to quer

2025

MEXA: Multilingual Evaluation of English-Centric LLMs via Cross-Lingual Alignment

ACL 2025finding

English-centric large language models (LLMs) often show strong multilingual capabilities. However, their multilingual performance remains unclear and is under-evaluated for many other languages. Most benchmarks for multilinguality focus on classic NLP tasks or cover a minimal number of languages. We…

2025

NoLiMa: Long-Context Evaluation Beyond Literal Matching

ICML 2025poster

Recent large language models (LLMs) support long contexts ranging from 128K to 1M tokens. A popular method for evaluating these capabilities is the needle-in-a-haystack (NIAH) test, which involves retrieving a "needle" (relevant information) from a "haystack" (long irrelevant context). Extensions of…

2025

Time Course MechInterp: Analyzing the Evolution of Components and Knowledge in Large Language Models

ACL 2025finding

Understanding how large language models (LLMs) acquire and store factual knowledge is crucial for enhancing their interpretability, reliability, and efficiency. In this work, we analyze the evolution of factual knowledge representation in the OLMo-7B model by tracking the roles of its Attention Head…

2024

Consistent Document-level Relation Extraction via Counterfactuals

EMNLP 2024finding

Many datasets have been developed to train and evaluate document-level relation extraction (RE) models. Most of these are constructed using real-world data. It has been shown that RE models trained on real-world data suffer from factual biases. To evaluate and address this issue, we present CovEReD,…

2023

DecompX: Explaining Transformers Decisions by Propagating Token Decomposition

ACL 2023long

An emerging solution for explaining Transformer-based models is to use vector-based analysis on how the representations are formed. However, providing a faithful vector-based explanation for a multi-layer model could be challenging in three aspects: (1) Incorporating all components into the analysis…

2022

AdapLeR: Speeding up Inference by Adaptive Length Reduction

ACL 2022long

Pre-trained language models have shown stellar performance in various downstream tasks. But, this usually comes at the cost of high latency and computation, hindering their usage in resource-limited settings. In this work, we propose a novel approach for reducing the computational cost of BERT with…

2022

GlobEnc: Quantifying Global Token Attribution by Incorporating the Whole Encoder Layer in Transformers

NAACL 2022long

There has been a growing interest in interpreting the underlying dynamics of Transformers. While self-attention patterns were initially deemed as the primary option, recent studies have shown that integrating other components can yield more accurate explanations. This paper introduces a novel token…

2021

Exploring the Role of BERT Token Representations to Explain Sentence Probing Results

EMNLP 2021main

Several studies have been carried out on revealing linguistic features captured by BERT. This is usually achieved by training a diagnostic classifier on the representations obtained from different layers of BERT. The subsequent classification accuracy is then interpreted as the ability of the model…