Figure 6.
The network diagram illustrates a filtered co-occurrence network of top railway technology keywords. Nodes represent keywords and are sized by degree centrality, while connecting lines represent co-occurrence frequency. Signal appears as a central node with strong connections to Speed, Sensor, Control, and Device, indicating frequent co-occurrence. Speed and Device also show high centrality and thick connecting links with Sensor and Control. Peripheral keywords include Track, Circuit, Brake, Electrical, and Manufacturing, each connected with fewer and thinner links. A legend indicates keyword categories labelled Active, Hot, and Other, degree centrality values ranging from 14 to 16, and co-occurrence strengths from 0.7 to 1.0.Visualization of the filtered social network of technology keywords