## 2 Literature Review  
### Traditional Construction Information Classification System  
The construction information classification system originated in the United States in 1920 with the American Institute of Architects (AIA); it initially classified building materials and later expanded to include building types. In 1963, the Construction Specification Institute (CSI) introduced a standardized format for building specifications, which rapidly became the industry standard. Subsequently, in 1966, the AIA, CSI, and other stakeholders collaborated to develop this system into a unified framework for construction specifications, data filtering, and cost accounting, facilitating the organization and exchange of technical information across the construction industry [7]. These collaborative efforts led to the revision and renaming of the system as MASTER-FORMAT in 1978 [8]. In the United States, the classification system primarily focuses on cost management, specification organization, project management, and data consolidation [9; 10]. In 1945, the Ministry of Construction Library in the United Kingdom extracted only the construction elements from the International Decimal Classification, a general book classification method, and presented the Universal Decimal Classification extraction method. The British Standards Association officially announced this method in 1948 [11; 12]. In 1947, construction companies centered around the Swedish Institute of Architects collaborated to develop Samarbetkommitten for Byggadsfragor (SfB) [13], a system that classified a construction information classification system into three facets: functional elements, construction types, and materials. The concept behind SfB significantly influenced many subsequent classification systems, leading to the creation of various forms of classification system [14; 15]. The first classification system designed for computer processing, known as the Coordinated Building Communication System, was developed in 1963. It enabled the generation of computerized itemized statements for construction purposes. Later, in 1968, the Royal Institute of Architects in England introduced the Construction Index/Samarbetskommitten for Byggadsfragor (CI/SfB) classification system [16]. This system expanded the classification into five facets (facilities, parts, construction types, materials, and other) by applying an analytic-synthetic classification system [17]. Major construction companies in South Korea began adopting the CI/SfB system in the 1980s. The Technical Subcommittee TC59/SC13 of the International Organization for Standardization (ISO) has overseen construction information classification systems since 1988. However, individual countries have the flexibility to propose their own classification systems based on specific needs. In the United Kingdom, the NBS introduced UniClass2015 as an integrated classification system for the construction industry, whereas the CSI in the United States presented OmniClass [18]. These classification systems establish a standardized foundation for classifying construction information throughout the entire project lifecycle. Furthermore, they are actively being developed for the digital transformation of and integration with building information modeling (BIM) in the construction industry. Previous studies focused on classification methods for information related to completed buildings within the construction domain. Therefore, these methods have limited applicability to infrastructure facilities, which often exhibit atypical features, such as varied topography. Figure 2 presents an analysis of all the items in UniClass [19] and OmniClass [20], indicating that information elements directly associated with infrastructure construction represent 17% of OmniClass and 13% of UniClass. Uniclass also considers the infrastructure sector [21]. However, its utilization in infrastructure is low because it primarily focuses on buildings [22]. Omniclass makes similar assessments [23; 24; 25].