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Ziwei Ji

24 accepted papers

2025

Calibrating Verbal Uncertainty as a Linear Feature to Reduce Hallucinations

EMNLP 2025

LLMs often adopt an assertive language style also when making false claims. Such ”overconfident hallucinations” mislead users and erode trust. Achieving the ability to express in language the actual degree of uncertainty around a claim is therefore of great importance. We find that ”verbal uncertain

Cited by 0SourcePDFScholar
2025

HalluLens: LLM Hallucination Benchmark

ACL 2025long

Large language models (LLMs) often generate responses that deviate from user input or training data, a phenomenon known as “hallucination.” These hallucinations undermine user trust and hinder the adoption of generative AI systems. Addressing hallucinations is important for the advancement of LLMs.…

2025

High-Dimension Human Value Representation in Large Language Models

NAACL 2025long

The widespread application of Large Language Models (LLMs) across various tasks and fields has necessitated the alignment of these models with human values and preferences. Given various approaches of human value alignment, such as Reinforcement Learning with Human Feedback (RLHF), constitutional le…

2025

Mixture-of-Recursions: Learning Dynamic Recursive Depths for Adaptive Token-Level Computation

NeurIPS 2025poster

Scaling language models unlocks impressive capabilities, but the accompanying computational and memory demands make both training and deployment expensive. Existing efficiency efforts typically target either parameter sharing or adaptive computation, leaving open the question of how to attain both s…

Cited by 0SourceScholar
2025

Relaxed Recursive Transformers: Effective Parameter Sharing with Layer-wise LoRA

ICLR 2025poster

Large language models (LLMs) are expensive to deploy. Parameter sharing offers a possible path towards reducing their size and cost, but its effectiveness in modern LLMs remains fairly limited. In this work, we revisit "layer tying" as form of parameter sharing in Transformers, and introduce novel m…

Cited by 5SourcePDFScholar
2024

ANAH-v2: Scaling Analytical Hallucination Annotation of Large Language Models

NeurIPS 2024poster

Large language models (LLMs) exhibit hallucinations in long-form question-answering tasks across various domains and wide applications. Current hallucination detection and mitigation datasets are limited in domain and size, which struggle to scale due to prohibitive labor costs and insufficient reli…

2024

ANAH: Analytical Annotation of Hallucinations in Large Language Models

ACL 2024long

Reducing the ‘hallucination' problem of Large Language Models (LLMs) is crucial for their wide applications. A comprehensive and fine-grained measurement of the hallucination is the first key step for the governance of this issue but is under-explored in the community.Thus, we present ANAH, a biling…

2024

Think before you speak: Training Language Models With Pause Tokens

ICLR 2024poster

Language models generate responses by producing a series of tokens in immediate succession: the $(K+1)^{\rm th}$ token is an outcome of manipulating $K$ hidden vectors per layer, one vector per preceding token. What if instead we were to let the model manipulate say, $K+10$ hidden vectors, before it…

Cited by 76SourcePDFScholar
2023

Contrastive Learning for Inference in Dialogue

EMNLP 2023long main

Inference, especially those derived from inductive processes, is a crucial component in our conversation to complement the information implicitly or explicitly conveyed by a speaker. While recent large language models show remarkable advances in inference tasks, their performance in inductive reaso…

Cited by 0SourcecodeScholar
2023

Diverse and Faithful Knowledge-Grounded Dialogue Generation via Sequential Posterior Inference

ICML 2023poster

The capability to generate responses with diversity and faithfulness using factual knowledge is paramount for creating a human-like, trustworthy dialogue system. Common strategies either adopt a two-step paradigm, which optimizes knowledge selection and response generation separately, and may overlo…

2023

NusaCrowd: Open Source Initiative for Indonesian NLP Resources

ACL 2023findings

We present NusaCrowd, a collaborative initiative to collect and unify existing resources for Indonesian languages, including opening access to previously non-public resources. Through this initiative, we have brought together 137 datasets and 118 standardized data loaders. The quality of the dataset…

2023

RHO: Reducing Hallucination in Open-domain Dialogues with Knowledge Grounding

ACL 2023findings

Dialogue systems can leverage large pre-trained language models and knowledge to generate fluent and informative responses. However, these models are still prone to produce hallucinated responses not supported by the input source, which greatly hinders their application. The heterogeneity between ex…

2023

Towards Mitigating LLM Hallucination via Self Reflection

EMNLP 2023long findings

Large language models (LLMs) have shown promise for generative and knowledge-intensive tasks including question-answering (QA) tasks. However, the practical deployment still faces challenges, notably the issue of "hallucination", where models generate plausible-sounding but unfaithful or nonsensical…

Cited by 0SourceScholar
2022

Actor-critic is implicitly biased towards high entropy optimal policies

ICLR 2022poster

We show that the simplest actor-critic method — a linear softmax policy updated with TD through interaction with a linear MDP, but featuring no explicit regularization or exploration — does not merely find an optimal policy, but moreover prefers high entropy optimal policies. To demonstrate the stre…

Cited by 18SourcePDFScholar
2022

Agnostic Learnability of Halfspaces via Logistic Loss

ICML 2022oral

We investigate approximation guarantees provided by logistic regression for the fundamental problem of agnostic learning of homogeneous halfspaces. Previously, for a certain broad class of “well-behaved” distributions on the examples, Diakonikolas et al. (2020) proved an tilde{Omega}(OPT) lower boun…

Cited by 7SourcePDFScholar
2022

Reproducibility in Optimization: Theoretical Framework and Limits

NeurIPS 2022accept

We initiate a formal study of reproducibility in optimization. We define a quantitative measure of reproducibility of optimization procedures in the face of noisy or error-prone operations such as inexact or stochastic gradient computations or inexact initialization. We then analyze several convex o…

Cited by 25SourcePDFScholar
2021

CrossNER: Evaluating Cross-Domain Named Entity Recognition

AAAI 2021technical

Cross-domain named entity recognition (NER) models are able to cope with the scarcity issue of NER samples in target domains. However, most of the existing NER benchmarks lack domain-specialized entity types or do not focus on a certain domain, leading to a less effective cross-domain evaluation. To…

2020

Polylogarithmic width suffices for gradient descent to achieve arbitrarily small test error with shallow ReLU networks

ICLR 2020poster

Recent theoretical work has guaranteed that overparameterized networks trained by gradient descent achieve arbitrarily low training error, and sometimes even low test error. The required width, however, is always polynomial in at least one of the sample size $n$, the (inverse) target error $1/\epsil…

Cited by 223SourceScholar