## 5 Discussion  
We propose a link-based approach to input-output analysis that reveals structurally important industries overlooked by traditional centrality metrics. Our findings demonstrate that even industries with low centrality can play critical roles in resource and information flows, offering new insights into industrial structure and strategic policy planning.  
We examined Korea's industrial network from two perspectives: centrality analysis and link-based analysis. Through this, we identified that the transportation and logistics industry plays a central role in the industrial ecosystem through its essential linkage with resource-based industries. This approach highlights the diversity of network analysis and offers a crucial foundation for enhancing its policy applicability.  
The node centrality index represents the influence of each industry (node) in the overall network. Among them, livestock products recorded the highest weighted degree centrality at 295,858,834. This means that the livestock products industry plays a key role as a connection link in the network. However, using only the node centrality index makes it difficult to fully capture the complexity and structural characteristics of the transportation and logistics industry within the industrial network.  
The link-based network analysis of the transportation and logistics industry revealed that the shortest distance was between the coal and petroleum products industry and the coal, crude oil, and natural gas industries. This suggests that resource-based industries are  
Figure 4: Distribution of node centrality metrics by industry.  
primary industries playing an essential role in the transportation and logistics industry. Also, we derived shortest-path distances to define the transportation and logistics industry ecosystem through potential nodes. Accordingly, the related industries were classified into primary, secondary, and tertiary industries, and a new transportation and logistics industry ecosystem was defined through this process. In particular, we rediscovered an industry that had been overlooked by traditional centrality indicators and provided new insights into network research by demonstrating the importance of link-based analytics. For example, even though the electrical equipment industry shows low centrality across the overall network, it has been classified as a major industry according to link-based analysis. As a result, the electrical equipment industry has been identified as a link between key resource flows in the transportation and logistics industry ecosystem. This can facilitate the efficient flow of information and resources across the entire network, despite the low direct-connection strength.  
These results could contribute to a re-evaluation of the strategic importance of the transportation and logistics industry network and the role of its related industries. The top 10 shortest paths presented in Table 4 help explain that the transportation and logistics industry acts as an important connection link in production and supply networks. As stated above, link-based analysis uncovers the potential industries that may be overlooked in traditional centrality indices, and these industries serve as crucial pathways that other industries must pass through within the network.