Network-based landscape of research strengths of universities in Mainland China

Abstract

A landscape of a complex system presents a quantitative measure of its global state. The profile of research strength in mainland China is investigated in detail, by which we illustrate a complex network based framework to extract a landscape from detailed records. First, a measure analogous to the Jaccard similarity is proposed to calculate from the presided funds similarities between the top-ranked universities. The neighbor threshold method is employed to reconstruct the similarity network of the universities. Second, the network is divided into communities. In each community the node with the largest degree and the smallest average shortest path length is taken as the representative of the community, called central node. The node bridging each pair of communities is defined to be a boundary. The central nodes and boundaries cooperatively give us a picture of the research strength landscape. Third, the evolutionary behavior is monitored by the fission and fusion probability matrices, elements of which are the percentage of a community at present time that joins into every community at the next time, and the percentage of a community at next time that comes from every present community, respectively. The landscapes in three successive 4-year durations are identified. It was found that some types of universities, such as the medicine&pharmacy and the finance&economy, conserve in single communities in the more than ten years, respectively. The agriculture&forest universities tend to cluster into one community. Meanwhile the engineering type distributes in different communities and tends to mix with the comprehension type. This framework can be used straightforwardly to analyze temporal networks. It provides also a new network-based method for multivariate time series analysis.

Evolution of the Internet AS-level topology: From nodes and edges to components

“…The Jaccard similarity theory, known as intersection over union and the Jaccard similarity coefficient, is a statistic that is used to compare the similarity and diversity of sample objects. [26,27] Inspired by Jaccard's theory, to study the object's evolutionary behaviors on a time-series, we focus on the changes that the system undergoes during its evolution and the dynamic evolution mechanism of the Internet. This is different from the classic methods of studying the evolution of the Internet, which have mainly investigated the phenomena and behaviors of the Internet.…”