activity
20182021
collaborators

6 papers

cs.IR2021

Trust your neighbors: A comprehensive survey of neighborhood-based methods for recommender systems

Athanasios N. Nikolakopoulos, Xia Ning, Christian Desrosiers +1

Collaborative recommendation approaches based on nearest-neighbors are still highly popular today due to their simplicity, their efficiency, and their ability to produce accurate a…

math.NA2020

Projection techniques to update the truncated SVD of evolving matrices

Vassilis Kalantzis, Georgios Kollias, Shashanka Ubaru +3

This paper considers the problem of updating the rank-k truncated Singular Value Decomposition (SVD) of matrices subject to the addition of new rows and/or columns over time. Such…

cs.SI2020

Random Surfing Revisited: Generalizing PageRank's Teleportation Model

Athanasios N. Nikolakopoulos

We revisit the Random Surfer model, focusing on its--often overlooked--Teleportation component, and we introduce NCDawareRank; a novel ranking framework designed to exploit network…

cs.IR2019

Boosting Item-based Collaborative Filtering via Nearly Uncoupled Random Walks

Athanasios N. Nikolakopoulos, George Karypis

Item-based models are among the most popular collaborative filtering approaches for building recommender systems. Random walks can provide a powerful tool for harvesting the rich n…

math.OC2018

Fast Decentralized Optimization over Networks

Meng Ma, Athanasios N. Nikolakopoulos, Georgios B. Giannakis

The present work introduces the hybrid consensus alternating direction method of multipliers (H-CADMM), a novel framework for optimization over networks which unifies existing dist…

stat.ML2018

Adaptive Diffusions for Scalable Learning over Graphs

Dimitris Berberidis, Athanasios N. Nikolakopoulos, Georgios B. Giannakis

Diffusion-based classifiers such as those relying on the Personalized PageRank and the Heat kernel, enjoy remarkable classification accuracy at modest computational requirements. T…