Extractive Summarization and Dialogue Act Modeling on Email Threads: An Integrated Probabilistic Approach
Summary
The paper tests whether recognizing dialogue acts in email threads helps identify the sentences that belong in an extractive summary, a link that earlier work largely ignored. The authors build a supervised sequential model, a DCRF, that predicts summary membership and dialogue act labels together rather than in separate stages. To capture thread structure, they convert each conversation into a fragment quotation graph, following Carenini et al. Each path through the graph becomes one training sequence. Sentences that appear on several paths receive their final label by majority vote. Features include sentence length, relative position, overlap with the thread title and subject, question marks, CC, participation dominance and a simplified ClueWordScore. For dialogue acts, the model also uses abstracted word and POS n-grams. On the BC3 corpus, the joint model clearly beats separate CRF and SVM baselines at selecting summary sentences, and its dialogue act accuracy stays at the same level. This suggests that modeling conversational function jointly is a practical way to improve email summarization.
Key points
- Data and evaluation. Experiments use the BC3 email corpus (about 1300 sentences). Results are averaged over five runs of 10-fold cross-validation, and significance is checked with a paired t-test.
- Summarization results. The DCRF reaches an F-measure of 0.485, against 0.428 for the CRF and 0.397 for the SVM. The gain comes mainly from higher recall (0.457).
- Combined task. Here a sentence counts as correct only if both its summary label and its dialogue act are right. On this measure the DCRF scores F' = 0.352, against 0.324 for the CRF and 0.292 for the SVM, and the differences are significant.
- Dialogue act results. Micro accuracy is nearly identical across models (DCRF 0.785, CRF 0.779, SVM 0.775). The two sequential models clearly beat the SVM on macro accuracy, but the DCRF's advantage over the CRF is not significant.
- Rare acts. The R, Su and M acts have only 68, 73 and 97 examples, and all models classify them poorly. The authors attribute this to n-gram sparsity. Q is easy to detect because its features, such as "?", are distinctive.
Cited by
Cite
@inproceedings{oya2014extractive,
title = {{Extractive Summarization and Dialogue Act Modeling on Email Threads: An Integrated Probabilistic Approach}},
author = {Oya, Tatsuro and Carenini, Giuseppe},
booktitle = {Proceedings of the 15th Annual Meeting of the Special Interest Group on Discourse and Dialogue (SIGDIAL)},
year = {2014},
doi = {10.3115/v1/w14-4318},
url = {https://doi.org/10.3115/v1/w14-4318}
}References
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