Yizhou Jin

Author directory

2026

Knowledge editing for large language models typically treats a fact update as a replacement in which a new object overwrites the old. Many real-world facts, however, evolve through sequences: the same subject–relation pair maps to different objects across disjoint intervals, each correct within its validity window. Existing temporal-editing benchmarks probe latest-value or explicit-time recall, so they cannot determine whether an edited model retains a coherent timeline. We introduce TKE-Bench, a diagnostic benchmark that operationalizes temporal accessibility along three reasoning-oriented axes with paraphrased variants. On TKE-Bench, all evaluated editing baselines collapse on chronologically structured queries, revealing catastrophic temporal interference (CTI). We trace CTI to a geometric property implicit in locate-and-edit methods: mid-layer subject-token keys are nearly collinear across time slices of the same subject, so stacked updates write along one direction and the latest edit overwrites every earlier value. Building on this, we propose ChronoExpert, a temporal mixture-of-experts that stores each time slice in an independent lightweight expert and activates only the matching one at inference, leaving the base model otherwise untouched. Across multiple LLM backbones, ChronoExpert consistently outperforms the strongest editing baselines and stays robust as chains grow longer.
Automatic fact verification (FV) predicts the veracity of a claim against retrieved evidence, yet modern verifiers often behave as shortcut-driven verifiers, predicting from surface regularities in the claim rather than the factual content of the evidence. Existing debiasing methods over-correct this by uniformly enforcing evidence reliance on every sample, thereby suppressing the valid information already carried by the claim itself. We propose Evidence-Grounded Remixing for Fact Verification (EGR-FV), which estimates a per-sample evidence necessity score by contrasting claim-with-evidence and claim-only predictions, and uses it to remix training batches so that debiasing is adapted to each sample’s actual reliance on evidence. On FEVER, PolitiHop, and HOVER together with their symmetric counterparts, EGR-FV achieves state-of-the-art accuracy and robustness, validating the effectiveness of EGR-FV.
Retrieval-augmented generation (RAG) improves factual question answering by grounding LLMs in external evidence, but it becomes brittle when retrieved context conflicts with the parametric memory of the model. Existing training-free methods often address this problem by globally comparing two knowledge sources or structurally aligning them, yet they still struggle with three coupled failure axes: question complexity, long misleading evidence, and off-target parametric recall. We first quantitatively analyze the individual and joint effects of these three axes, showing that their interaction makes knowledge conflict resolution harder than any single axis alone. Motivated by this finding, we propose TRIAD, a training-free framework for knowledge conflict resolution in RAG. TRIAD decomposes a question into minimal subquestions, performs subquestion-level evidence calibration to retain concise and sufficient evidence, and uses indirect clues from calibrated evidence to guide parametric knowledge elicitation. Across three benchmarks and six LLMs, TRIAD achieves state-of-the-art performance and is the only method that surpasses a setting with additional retrieval in most cases. Additional experiments further demonstrate its generalization and worst-case robustness.