Affiner les résultats

Type de document

Collection spécifique

Langue

Université de Fribourg

Similarity-based classification in partially labeled networks

Zhang, Qian-Ming ; Shang, Ming-Sheng ; Lü, Linyuan

In: International Journal of Modern Physics C, 2010, vol. 21, no. 6, p. 813-824

Two main difficulties in the problem of classification in partially labeled networks are the sparsity of the known labeled nodes and inconsistency of label information. To address these two difficulties, we propose a similarity-based method, where the basic assumption is that two nodes are more likely to be categorized into the same class if they are more similar. In this paper, we introduce ten...

Université de Fribourg

Empirical comparison of local structural similarity indices for collaborative-filtering-based recommender systems

Zhang, Qian-Ming ; Shang, Ming-Sheng ; Zeng, Wei ; Chen, Yong ; Lü, Linyuan

In: Physics Procedia, 2010, vol. 3, no. 5, p. 1887-1896

Collaborative filtering is one of the most successful recommendation techniques, which can effectively predict the possible future likes of users based on their past preferences. The key problem of this method is how to define the similarity between users. A standard approach is using the correlation between the ratings that two users give to a set of objects, such as Cosine index and Pearson...

Université de Fribourg

Empirical analysis of web-based user-object bipartite networks

Shang, Ming-Sheng ; Lü, Linyuan ; Zhang, Yi-Cheng ; Zhou, Tao

In: Europhysics Letters, 2010, vol. 90, no. 4, p. 48006

Understanding the structure and evolution of web-based user-object networks is a significant task since they play a crucial role in e-commerce nowadays. This letter reports the empirical analysis on two large-scale web sites, audioscrobbler.com (http://audioscrobbler.com/) and del.icio.us (http://del.icio.us/), where users are connected with music groups and bookmarks, respectively. The degree...

Université de Fribourg

Link prediction based on local random walk

Liu, Weiping ; Lü, Linyuan

In: Europhysics Letters, 2010, vol. 89, no. 5, p. 58007

The problem of missing link prediction in complex networks has attracted much attention recently. Two difficulties in link prediction are the sparsity and huge size of the target networks. Therefore, to design an efficient and effective method is of both theoretical interest and practical significance. In this letter, we proposed a method based on local random walk, which can give competitively...

Université de Fribourg

Link prediction in weighted networks: The role of weak ties

Lü, Linyuan ; Zhou, Tao

In: EPL Europhysics Letters, 2010, vol. 89, no. 1, p. 18001

Plenty of algorithms for link prediction have been proposed and were applied to various real networks. Among these algorithms, the weights of links are rarely taken into account. In this letter, we use local similarity indices to estimate the likelihood of the existence of links in weighted networks, including Common Neighbor, Adamic-Adar Index, Resource Allocation Index, and their weighted...

Université de Fribourg

Relevance is more significant than correlation: Information filtering on sparse data

Shang, Ming-Sheng ; Lü, Linyuan ; Zeng, Wei ; Zhang, Yi-Cheng ; Zhou, Tao

In: Europhysics Letters, 2009, vol. 88, no. 6, p. 68008

In some recommender systems where users can vote objects by ratings, the similarity between users can be quantified by a benchmark index, namely the Pearson correlation coefficient, which reflects the rating correlations. Another alternative way is to calculate the similarity based solely on the relevance information, namely whether a user has voted an object. The former one uses more information...

Université de Fribourg

Similarity index based on local paths for link prediction of complex networks

Lü, Linyuan ; Jin, Ci-Hang ; Zhou, Tao

In: Physical Review E, 2009, vol. 80, no. 4, p. 046122

Predictions of missing links of incomplete networks, such as protein-protein interaction networks or very likely but not yet existent links in evolutionary networks like friendship networks in web society, can be considered as a guideline for further experiments or valuable information for web users. In this paper, we present a local path index to estimate the likelihood of the existence of a...

Université de Fribourg

The role of a matchmaker in buyer-vendor interactions

Lü, Linyuan ; Medo, Matúš ; Zhang, Yi-Cheng

In: The European Physical Journal B, 2009, vol. 71, no. 4, p. 565-571

We consider a simple market where a vendor offers multiple variants of a certain product and preferences of both the vendor and potential buyers are heterogeneous and possibly even antagonistic. Optimization of the joint benefit of the vendor and the buyers turns the toy market into a combinatorial matching problem. We compare the optimal solutions found with and without a matchmaker, examine...

Université de Fribourg

Predicting missing links via local information

Zhou, Tao ; Lü, Linyuan ; Zhang, Yi-Cheng

In: The European Physical Journal B, 2009, vol. 71, no. 4, p. 623-630

Missing link prediction in networks is of both theoretical interest and practical significance in modern science. In this paper, we empirically investigate a simple framework of link prediction on the basis of node similarity. We compare nine well- known local similarity measures on six real networks. The results indicate that the simplest measure, namely Common Neighbours, has the best...

Université de Fribourg

Empirical analysis on a keyword-based semantic system

Zhang, Zi-Ke ; Lü, Linyuan ; Liu, Jian-Guo ; Zhou, Tao

In: The European Physical Journal B, 2008, vol. 66, no. 4, p. 557-561

Keywords in scientific articles have found their significance in information filtering and classification. In this article, we empirically investigated statistical characteristics and evolutionary properties of keywords in a very famous journal, namely Proceedings of the National Academy of Science of the United States of America (PNAS), including frequency distribution, temporal scaling...