this is the data used in my article "research front detection and topic evolution based on topological structure and PageRank algorithm". The data include the scientific documents in Dataset I (D1.txt), the scientific documents
in Dataset II (D2.txt), the scientific documents in Dataset I without isolated
document (D3.txt), and the scientific documents in Dataset II without isolated
document (D4.txt), the unique number of scientific documents (D5.txt), the similarity
between scientific documents for document clustering (D6.txt), and the
similarity between clusters for topic evolution (D7.txt)
