Analysis of cooperative research and development networks on Japanese patents

To sustain economic growth, countries have to manage systems in order to create technological innovation. To meet this goal, they are developing policies that organically connect companies, national laboratories, and universities into innovation networks. However, the whole structures of these connections have been little investigated because of the difficulty of obtaining such data.We use Japanese patent data and create a network of jointly applying organizations. This network can be considered as one representation of an innovation network because patents are seeds of innovation and joint applications are strong evidence of connections between organizations. We investigated the structure of the network, especially whether or not the degree distribution follows a power law. After that, we also propose a model that generates the actual network, not only degree distribution, but also link distance distribution.