Refine my results

Language

Consortium of Swiss Academic Libraries

Cooperative dynamics of loyal customers in queueing networks

Gallay, Olivier ; Hongler, Max-Olivier

In: Journal of Systems Science and Systems Engineering, 2008, vol. 17, no. 2, p. 241-254

Université de Fribourg

Degree correlation of bipartite network on personalized recommendation

Liu, Jian-Guo ; Zhou, Tao ; Zhang, Yi-Cheng ; Guo, Qiang

In: International Journal of Modern Physics C, 2010, vol. 21, no. 1, p. 137-147

In this paper, the statistical property, namely degree correlation between users and objects, is taken into account and be embedded into the similarity index of collaborative filtering (CF) algorithm to improve the algorithmic performance. The numerical simulation on a benchmark data set shows that the algorithmic accuracy of the presented algorithm, measured by the average ranking score, is...

Université de Fribourg

Adaptive model for recommendation of news

Medo, Matúš ; Zhang, Yi-Cheng ; Zhou, Tao

In: Europhysics Letters, 2009, vol. 88, no. 3, p. 38005

Most news recommender systems try to identify users' interests and news' attributes and use them to obtain recommendations. Here we propose an adaptive model which combines similarities in users' rating patterns with epidemic-like spreading of news on an evolving network. We study the model by computer agent-based simulations, measure its performance and discuss its robustness against bias and...

Université de Fribourg

Accurate and diverse recommendations via eliminating redundant correlations

Zhou, Tao ; Su, Ri-Qi ; Liu, Run-Ran ; Jiang, Luo-Luo ; Wang, Bing-Hong ; Zhang, Yi-Cheng

In: New Journal of Physics, 2009, vol. 11, p. 123008

In this paper, based on a weighted projection of a bipartite user-object network, we introduce a personalized recommendation algorithm, called network-based inference (NBI), which has higher accuracy than the classical algorithm, namely collaborative filtering. In NBI, the correlation resulting from a specific attribute may be repeatedly counted in the cumulative recommendations from different...

Université de Fribourg

Collaborative filtering based on multi-channel diffusion

Shang, Ming-Sheng ; Jin, Ci-Hang ; Zhou, Tao ; Zhang, Yi-Cheng

In: Physica A: Statistical Mechanics and its Applications, 2009, vol. 388, no. 23, p. 4867-4871

In this paper, by applying a diffusion process, we propose a new index to quantify the similarity between two users in a user–object bipartite graph. To deal with the discrete ratings on objects, we use a multi-channel representation where each object is mapped to several channels with the number of channels being equal to the number of different ratings. Each channel represents a certain...

Université de Fribourg

Accelerating consensus of self-driven swarm via adaptive speed

Zhang, Jue ; Zhao, Yang ; Tian, Baomei ; Peng, Liqian ; Zhang, Hai-Tao ; Wang, Bing-Hong ; Zhou, Tao

In: Physica A: Statistical Mechanics and its Applications, 2009, vol. 3888, no. 7, p. 1237-1242

In recent years, the well-developed Vicsek model has attracted more and more attention. Unfortunately, in-depth research on its convergence speed is not yet completed. In this paper, we investigate some key factors governing the convergence speed of the Vicsek model with the assistance of extensive numerical simulations. A significant phenomenon surfaces that the convergence time scales obeys a...

Université de Fribourg

Consensus of self-driven agents with avoidance of collisions

Peng, Liqian ; Zhao, Yang ; Tian, Baomei ; Zhang, Jue ; Wang, Bing-Hong ; Zhang, Hai-Tao ; Zhou, Tao

In: Physical Review E, 2009, vol. 79, no. 2, p. 026113

In recent years, many efforts have been addressed on collision avoidance of collectively moving agents. In this paper, we propose a modified version of the Vicsek model with adaptive speed, which can guarantee the absence of collisions. However, this strategy leads to an aggregated state with slowly moving agents. We therefore further add a certain repulsion, which results in both faster...

Université de Fribourg

Collective behavior coordination with predictive mechanisms

Zhang, Hai-Tao ; Chen, Michael ZhiQiang ; Stan, Guy-Bart ; Zhou, Tao ; Maciejowski, Jan M.

In: IEEE Circuits and Systems Magazine, 2008, vol. 6, no. 3, p. 67 - 85

In natural flocks/swarms, it is very appealing that low-level individual intelligence and communication can yield advanced coordinated collective behaviors such as congregation, synchronization and migration. In the past few years, the discovery of collective flocking behaviors has stimulated much interest in the study of the underlying organizing principles of abundant natural groups, which has...