Due to the large-scale and multiscale natures of social media data, sparse representation (SR) learning methods are widely followed. However, there are three problems associated with the existing SR methods: 1) they neglect the fact that the semantic features of data may change during iterative learning, which leads to weak semantic learning; 2) they often assume that the data are linearly separable, while the data might be nonlinear in many real-world applications; and 3) they cannot ensure the low-rank and discriminative properties of the data at the same time and might neglect the global properties of the data, leading to suboptimal solutions. To solve these problems, we propose a novel method, named kernel-based SR learning with global and local low-rank label (KSR-GL3) constraint, which strengthens the semantic information and ensures the semantic features invariant during learning. First, we map the data into a high-dimensional feature space to learn the linear representation of samples. Second, global and local low-rank label (GL3) constraint is used to ensure the semantic invariance, low-rankness, and discrimination of features during learning. Third, an$\ell _{2,1}$is imposed to explore the sparseness of the subspace. Mathematical analyses show that GL3 can retain the intrinsic properties of data during learning. By combining the above three components, a generalized power iteration (GPI) approach is applied to build the model and deal with the tricky optimization problem. By KSR-GL 3, a sparse, low-rank, and discriminative subspace is produced from the high-dimensional and orthogonal representation of the data under the guidance of semantics, while the intrinsic properties of data are preserved. Extensive experiments on six datasets compared with five advanced algorithms demonstrate its promising prospects.

To accurately retrieve similar objects from different domains, domain adaptive retrieval method is applied to cope with the domain shift problem in information retrieval. However, existing methods still have two problems: a) they fail to filter out low-confidence samples, leading to error accumulation; and b) they ignore the negative effect of domain discrepancy. To address these two issues, we propose an efficient method called Dynamic Confidence Sampling and Label Semantic Guidance Learning (DCS-LSG). First, Dynamic Confidence Sampling (DCS) is employed to dynamically select high-confidence samples from the target domain so as to improve the effectiveness of learning. Second, Label Semantic Guidance (LSG) learning is presented to enhance the label semantics of features during domain adaptive retrieval. In addition, we introduce a Dual-Projection Relaxation (DPR) strategy to learn more effective features on two specific projection spaces. At last, a two-step hashing strategy is used to generate high-quality hash codes. Experiments on multiple cross-domain retrieval datasets demonstrate that the proposed DCS-LSG can achieve a significant performance improvement.

Cancer diseases are caused by combination of genetic, environmental, and lifestyle factors. Therefore, it is difficult for health organization to treat this disease. This study focuses on identifying the landscape of Cancer research by using bibliometric methods and social network analysis methods based on a number of research articles related to Cancer retrieved from PubMed. To deeply understand the landscape of research on this disease, we adopt productivity analysis which consists of author, university/institution, country and frequent MeSH terms analysis. We specifically perform the concept graph-based network analysis by applying four centrality measures and analyzing co-occurrence of MeSH terms. In the end, we propose a method to predict the Rising Star that may be the active researcher in the field of Cancer disease in the next few years. With this method, we can possibly find more academic cooperation via academic social networks. The encouraging results show that our work is highly feasible.

Social networks are very dynamic objects, since new edges and vertices are added to the graph over the time. Link prediction is an important task in social network analysis and is useful in many application domains. In the recent years, there is significant interest in methods that represent the social network in the form of a graph and leverage topological and semantic measures of similarity between two nodes to make predictions. In this article, we propose a hybrid approach utilizing time-varied weight information of links. We focus on the problem of link prediction particularly in the context of evolving co-authorship. Experiments have shown that the link prediction algorithm based on time-varied weight can reach better result.