## 2 Materials and Methods
### Data Collection and Processing
#### 2.1.1 Standard Collection and Terminology Extraction  
Standards are established norms and guidelines defining technical specifications and procedures. Countries and regions typically maintain their own standardization bodies tasked with the creation, publication, and oversight of these standards. Nationally, entities like the Standardization Administration of China and the American National Standards Institute play pivotal roles. Regionally, organizations such as the European Committee for Standardization and the Asia-Pacific Economic Cooperation's Subcommittee on Standards and Conformance are crucial. Internationally, major standardization bodies such as the International Organization for Standardization (ISO) [31], the International Telecommunication Union (ITU) [32], and the International Electrotechnical Commission (IEC) [33] contribute to global standards across various sectors.  
In China, the standards framework comprises national, industry, local, enterprise, and group standards. The National Standard Information Public Service Platform is a commonly used platform for these standards. Standard terminology refers to uniform terms and definitions used within specific fields or in the standards documents. Standards have well-defined and clear constitutive elements, with core technical components being highly specialized, complex, and filled with numerous proprietary terms and professional terminology specific to the gas industry.  
The standardized terms within these documents often include multiple nested terms with blurred boundaries. Due to copyright regulations, acquiring the full text of these standards is challenging. During the acquisition of standard data, some documents were purchased from standard platforms, some were obtained from a gas company, and others were from the official website of the Ministry of Housing and Urban-Rural Development of the People's Republic of China. Ultimately, 589 standard documents related to gas pipeline networks were collected. Table 2 presents examples of relevant Chinese standards for gas pipeline networks. These terms are usually presented in dedicated sections of the standards documents, including both the terms and their detailed explanations. Given the structured nature of these documents, iconic markers, such as section beginnings and endings, are used as reference points. We used Python tools to extract paragraphs containing standard terminology. After screening and deduplication, we re  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Acronym** & **Description** & **Owner** & **Link** \\ \hline PHMSA & Data about federally regulated and state-regulated natural gas pipelines, hazardous liquid pipelines, and liquefied natural gas (LNG) plants & Department of Transportation Pipeline and Hazardous Materials Safety Administration & [[https://www.phmsa.dot.gov/](https://www.phmsa.dot.gov/)]([https://www.phmsa.dot.gov/](https://www.phmsa.dot.gov/)) (accessed on 20 May 2024) \\ \hline eMARS & Reports of chemical accidents and near misses & MAHB (the Major Accident Hazards Bureau) & [[https://emars.jrc.ec.europa.eu/en/emars/content](https://emars.jrc.ec.europa.eu/en/emars/content)]([https://emars.jrc.ec.europa.eu/en/emars/content](https://emars.jrc.ec.europa.eu/en/emars/content))(accessed on 17 February 2024) \\ \hline OSHA & Accident investigation information is provided, including textual descriptions of the accident and details regarding the injuries and fatalities which occurred & OSHA (Occupational Safety and Health Administration) & [[https://www.osha.gov/severeinjury](https://www.osha.gov/severeinjury)]([https://www.osha.gov/severeinjury](https://www.osha.gov/severeinjury)) (accessed on 17 May 2024) \\ \hline \hline \end{tabular}
\end{table}
Table 1: Summary of gas pipeline network database resources.  
tained only the terms relevant to standard terminology, storing them in TXT format as a standard terminology lexicon.