Tianwei Xu

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The SIFT (Scale Invariant Feature Transform) is a computer vision algorithm that is used to detect and describe the local image features. The SIFT features are robust to changes in illumination, noise, and minor changes in viewpoint. The SIFT features have been used object recognition, image retrieval and matching, and so on.. The research of SIFT(More)
—As a powerful tool, ontology has been widely applied in social science, medicine science and computer science. In computer networks, especially, ontology is used for search extension, thus boost the quality of information retrieval. Ontology concept similarity calculation is an essential problem in these applications. A new method to get similarity between(More)
A graph G is called a fractional (g, f, n)-critical graph if any n vertices are removed from G, then the resulting graph admits a fractional (g, f)-factor. In this paper, we determine the new toughness condition for fractional (g, f, n)-critical graphs. It is proved that G is fractional (g, f, n)-critical if t(G) ≥ b 2 −1+bn a. This bound is sharp in some(More)
Pastoralists on the Tibetan alpine rangeland suffered great economic loss in cold season, due to serious live-weight loss of domestic livestock under traditional grazing management. This study aimed to evaluate the effect of dietary types (crude protein levels) on feed intakes, growth performance and economic returns of local Tibetan sheep and yaks during(More)
As an important data structure model, ontology has become one of the core contents in information science. Multi-dividing ontology algorithm combines the advantages of graph structure and learning algorithms proved to have high efficiency. In this paper, in terms of multi-dividing proper loss functions, we propose new multi-dividing ontology learning(More)
—In this paper, we determine the lower bound for the general sum connectivity index of molecular graphs with () G   2. The extremal molecular structure to reach the lower bound is also presented. Furthermore, we consider the lower bound and extremal molecular graph for triangle-free chemical structures. graph, general sum connectivity index, triangle-free(More)