{"slug": "bertilda-explainable-topic-lifecycle-tracking-with-split-merge-detection-via-and", "title": "BERTilda: Explainable Topic Lifecycle Tracking with Split/Merge Detection via Similarity-and-Flow Temporal Graphs", "summary": "Researchers introduced BERTilda, an explainable framework that tracks topic lifecycles in longitudinal text streams by detecting splits, merges, continuations, and disappearances using similarity-and-flow temporal graphs. Evaluated on political corpora including U.S. congressional tweets and historical speech datasets, BERTilda achieved majority agreement rates up to 87% on a gold-standard subset annotated by three independent annotators, outperforming similarity-only and forward-only baselines in disappearance detection.", "body_md": "arXiv:2608.18101v1 Announce Type: new\nAbstract: Longitudinal text streams exhibit topic birth and death, but also discrete structural reorganizations in which themes split into subtopics or merge into broader narratives. Many dynamic topic models emphasize smooth drift, while snapshot topic models (fit independently per time window) leave temporal correspondence underspecified. We present BERTilda, an explainable framework that discovers topics independently in each window (using an embedding-based topic model) and then constructs a temporal topic graph linking topics across adjacent windows. Links are supported by two complementary signals: (i) semantic similarity between topic representations and (ii) a bidirectional coverage signal that estimates document outflow (where a topic goes) and inflow (where a topic comes from) via cross-window tweet-to-topic attribution. Graph-based rules label continuations, splits, merges, disappearances, and unclear transitions. We evaluate BERTilda on political corpora, including U.S. congressional tweets and historical speech datasets, report topic-quality and temporal-stability diagnostics, and validate lifecycle labels on a gold-standard subset annotated by three independent annotators. On the annotated subset, BERTilda reaches majority agreement rates up to 87% and attains the highest macro-average agreement across the compared methods, with particularly strong disappearance detection relative to similarity-only and forward-only baselines.", "url": "https://wpnews.pro/news/bertilda-explainable-topic-lifecycle-tracking-with-split-merge-detection-via-and", "canonical_source": "https://arxiv.org/abs/2608.18101", "published_at": "2026-08-20 04:00:00+00:00", "updated_at": "2026-08-20 04:13:01.870472+00:00", "lang": "en", "topics": ["natural-language-processing", "machine-learning"], "entities": ["BERTilda", "arXiv"], "alternates": {"html": "https://wpnews.pro/news/bertilda-explainable-topic-lifecycle-tracking-with-split-merge-detection-via-and", "markdown": "https://wpnews.pro/news/bertilda-explainable-topic-lifecycle-tracking-with-split-merge-detection-via-and.md", "text": "https://wpnews.pro/news/bertilda-explainable-topic-lifecycle-tracking-with-split-merge-detection-via-and.txt", "jsonld": "https://wpnews.pro/news/bertilda-explainable-topic-lifecycle-tracking-with-split-merge-detection-via-and.jsonld"}}