# Deep Learning-Based Automatic Summarization of Chinese Maritime Judgment Documents
## 3 Construction of Domain-Specific Lexicon for Maritime Judgment Documents Via Feature Analysis
### Construction of the Maritime Judgment Lexicon  
A domain lexicon is a structured collection of domain-specific terminology and core concepts, providing a standardized lexical foundation for communication, research, and practical activities among professionals. In the task of automatic summarization for maritime judgment documents, constructing such a lexicon is critical for enhancing model performance. Firstly, the inherent lack of explicit word delimiters in Chinese text amplifies the difficulty of identifying term boundaries. Secondly, the jurisprudential specificity and maritime particularity of these documents demand a higher level of accuracy in generating legally precise terminology. Thus, constructing a maritime judgment lexicon significantly improves the model's ability to recognize domain-specific terms, ensuring that generated summaries accurately reflect the core legal logic of the original documents.  
This paper utilizes 10,153 maritime judgment documents publicly available on China Judgments Online ([[https://wenshu.court.gov.cn/](https://wenshu.court.gov.cn/)]([https://wenshu.court.gov.cn/](https://wenshu.court.gov.cn/)), accessed on 13 March 2023) as the data source, covering cases from 11 maritime courts, including those in Dalian, Tianjin, and Shanghai. The textual length distribution of the corpus is shown in Figure 2, where the horizontal axis represents the number of characters in the judgment documents, and the vertical axis denotes the number of documents with the corresponding character count. It shows that the corpus exhibits a pronounced long-text characteristic: the average document length is 3006 characters, with 18.77% (1906 documents) exceeding 5000 characters.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Ranking** & **Cause of Action** & **Number of Cases** \\ \hline
1 & Dispute over contract of freight forwarding by sea or by waters leading to the sea & 9002 \\
2 & Disputes over contract of seaman service & 6515 \\
3 & Disputes over contract of carriage of goods by sea or by waters leading to the sea & 5892 \\
4 & Disputes over liability for personal injury at sea or at waters leading to the sea & 2155 \\
5 & Admiralty and maritime disputes & 1935 \\
6 & Disputes over contract of supply of ship stores and spares & 1617 \\
7 & Disputes over contract of sale and purchase of ship & 1118 \\
8 & Disputes over contract of insurance by sea or by waters & 1107 \\
9 & Charter party disputes & 1073 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Top nine causes of action in maritime court cases during 2023–2024.  
To construct the maritime judgment lexicon, this paper first employs regular expressions to develop three predefined domain-specific rule patterns for extracting legal terms from the corpus: law and regulation identification rules, case type recognition rules, and international treaty detection rules. Second, non-domain-specific terms are subsequently filtered out by combining a stopword list with manual rules (e.g., frequency thresholds). Finally, candidate legal and regulatory terms are validated against the National Database of Law and Regulation of China ([[https://flk.npc.gov.cn/](https://flk.npc.gov.cn/)]([https://flk.npc.gov.cn/](https://flk.npc.gov.cn/)), accessed on 22 February 2024) to ensure the lexicon's accuracy and authority. Through this process, an initial maritime judgment lexicon with 636 core terms is developed. To enhance domain-specific coverage, specialized vocabulary related to judicial trial is selectively incorporated. The final maritime judgment lexicon consists of 3005 standardized entries.