China's forest cover has been increasing in the past three decades, which is in sharp contrast to rapid declines in other natural resources. Understanding the mechanisms of forest recovery and their effects is essential for sustaining forests in China and elsewhere. Some studies suggest that...

In this paper, the relationship between the in-degree and out-degree of World-Wide Web is studies. At each time step, a new node with out-degree kout is added, where kout obeys the power-law distribution and its mean value is m. The analytical and simulation results suggest that the exponent of...

China's forest cover has been increasing in the past three decades, which is in sharp contrast to rapid declines in other natural resources. Understanding the mechanisms of forest recovery and their effects is essential for sustaining forests in China and elsewhere. Some studies suggest that...

In this paper, we introduce a modified collaborative filtering (MCF) algorithm, which has remarkably higher accuracy than the standard collaborative filtering. In the MCF, instead of the cosine similarity index, the user–user correlations are obtained by a diffusion process. Furthermore, by...

In this Brief Report, we propose an index of user similarity, namely, the transferring similarity, which involves all high-order similarities between users. Accordingly, we design a modified collaborative filtering algorithm, which provides remarkably higher accurate predictions than the...

In this paper, we propose a spreading activation approach for collaborative filtering (SACF). By using the opinion spreading process, the similarity between any users can be obtained. The algorithm has remarkably higher accuracy than the standard collaborative filtering using the Pearson...